Bio-based polyesters from cyclic monomers derived from carbohydrates

Bio-based polyes e s om cyclic monome s de i ed om ca bohyd a es Ph.D. Thesis p esen ed by C is ina La illa Aguila Di ec ed by P o . Sebas ián Muñoz Gue a Ba celona, Sep embe 2013 Tesi p esen ada pe ob eni el í ol de Doc o pe la Uni e si a Poli ècnica de Ca alunya Doc o a en Políme s i Biopolíme s Depa amen d’Enginye ia Química Escola Tècnica Supe io d’Enginye ia Indus ial de Ba celona Uni e si a Poli ècnica de Ca alunya i Abs ac Polyes e s a e ex emely e sa ile polyme s which can be used in a wide a ie y o applica ions anging om high pe o mance ma e ials o ecyclable and deg adable polyme s. The p epa a ion o polyes e s om enewable eeds ock is cu en ly ecei ing inc easing a en ion in bo h indus ial and academic esea ch. This Thesis is speci ically add essed o he de elopmen o alipha ic and a oma ic polyes e s wi h enhanced p ope ies made om ca bohyd a e-based cyclic ace alized monome s, i.e. a bicyclic ace alized alda ic acid de i ed om D-galac ose, bicyclic ace alized aldi ols de i ed om D-galac ose and D-mannose, and a cyclic ace alized aldi ol de i ed om L- a a ic acid. The no el alipha ic polyes e s de i ed om bicyclic ace alized galac a ic acid and D-manni ol, which a e biodeg adable ma e ials, a e dis inguished by p esen ing an enhanced igidi y compa ed o he alipha ic polyes e s commonly used so a , which in a iably in luences hei whole he mal and mechanical beha io . Bicyclic ace alized ca bohyd a e-based compounds a e also used as comonome s in he p epa a ion o andom poly(alkylene e eph hala e) copolyes e s by mel polycondensa ion (MP). Since linea α,ω-alkanediols wi h a ying leng h a e employed, and he copolyme iza ions wi h bicyclic monome s a e ca ied ou o a wide ange o composi ions, a de ailed s uc u e-p ope ies s udy is desc ibed. The e ec o he p esence o he ca bohyd a e-based comonome on he mal and mechanical p ope ies o he polyes e is la gely dependan on which uni , he diol o he diacid, is eplaced. The inco po a ion o ace alized aldi ols inc eases he he mal s abili y, he glass- ansi ion empe a u e and he mechanical modulus. On he con a y, hese pa ame e s a e diminished when he e eph hala e uni s a e eplaced by bicyclic ace alized galac a ic acid. Also he hyd oly ic and enzyma ic deg adabili y depends on he uni s in oduced in o he polyes e backbone. The inco po a ion o cyclic ace alized ca bohyd a e-based aldi ols in o he amo phous phase o poly(bu ylene e eph hala e) by he solid-s a e modi ica ion (SSM) echnique is epo ed, which leads o inc eases in glass- ansi ion empe a u e. The esul ing SSM-p epa ed copolyes e s ha e a unique block-like chemical mic os uc u e ha endows hem wi h supe io he mal p ope ies when compa ed o hei andom coun e pa s ob ained by MP. ii Gi en he s uc u al p oximi y be ween isoso bide and bicyclic ace alized aldi ols, as well as hei common po en ial use as polycondensa ion monome s, a compa a i e e alua ion o hei sui abili y o he syn hesis o a oma ic polyes e s is ca ied ou in his Thesis. The g ea e acili y o bicyclic ace alized aldi ols compa ed o isoso bide o eac unde he condi ions employed is highligh ed. Also he in luence o he symme y and s i ness o he bicyclic s uc u e on he he mal beha io o he copolyes e s is discussed. Key wo ds: polyes e , ca bohyd a es, bio-based, cyclic ace alized monome s, D-galac ose, D-mannose, L- a a ic acid, andom copolyes e s, block-like copolyes e s iii Resumen Los poliés e es son políme os ex emadamen e e sá iles que se usan en una amplia a iedad de aplicaciones, desde ma e iales de al as p es aciones a políme os eciclables o deg adables. La p epa ación de poliés e es a pa i de uen es eno ables gene a cada ez más in e és, an o en la indus ia como en el mundo académico. En es a Tesis se emplean uen es na u ales pa a desa olla nue os poliés e es ali á icos y a omá icos con p opiedades mejo adas, a pa i de monóme os cíclicos de i ados de ca bohid a os, i.e. un ácido aldá ico ace alizado bicíclico de i ado de D-galac osa, aldi oles ace alizados bicíclicos de i ados de D-galac osa y D-manosa, y un aldi ol ace alizado cíclico de i ado de ácido L- a á ico. Los nue os poliés e es ali á icos de i ados de ácido galac á ico y D-manni ol ace alizado bicíclico, que son ma e iales biodeg adables, des acan po p esen a una igidez mejo ada espec o a los poliés e es ali á icos comúnmen e usados has a aho a, hecho que in luencia in a iablemen e sus p opiedades é micas y mecánicas. También se epo a el uso de monóme os bicíclicos ace alizados de i ados de ca bohid a os pa a la p epa ación de copoliés e es poli(alquilen e e ala o)s con mic oes uc u a al aza , median e policondensación en undido (MP). Se emplean α,ω- alcanodioles lineales con di e en es longi udes, y las copolime izaciones con monóme os bicíclicos se lle an a cabo en un amplio ango de composiciones, lo que pe mi e desa olla un es udio es uc u a-p opiedades de allado. El e ec o de la unidad eno able en las p opiedades é micas y mecánicas del poliés e depende de qué unidad no eno able, diol o diácido, eemplaza. La inco po ación de aldi oles ace alizados aumen a la es abilidad é mica, la empe a u a de ansición í ea y el módulo elás ico. Po con a, es os pa áme os disminuyen cuando las unidades e e álicas se eemplazan po ácido galac á ico ace alizado bicíclico. Las unidades eno ables in oducidas a ec an ambién a la deg adabilidad hid olí ica y enzimá ica de los poliés e es. Median e la écnica de modi icación en es ado sólido (SSM), se inco po an aldi oles cíclicos ace alizados a la ase amo a del poli(bu ilen e e ala o), lo cual conlle a a un aumen o de su empe a u a de ansición í ea. Los copoliés e es esul an es p esen an una mic oes uc u a en bloques, que los do a de p opiedades é micas supe io es espec o a los copoliés e es análogos con mic oes uc u a al aza p epa ados median e MP. i En es a Tesis ambién se compa an las ca ac e ís icas y p opiedades del monóme o isoso bide y los aldi oles ace alizados bicíclicos pa a la sín esis de poliés e es a omá icos, debido a su p oximidad es uc u al, así como a su uso po encial como monóme os en policondensaciones. Se des aca la mayo acilidad de eacción en las condiciones empleadas de los aldi oles ace alizados bicíclicos compa ados con isoso bide. También se es udia la in luencia de la sime ía y igidez de la es uc u a bicíclica en las p opiedades é micas de los copoliés e es. Palab as cla e: poliés e , ca bohid a os, uen es na u ales, monóme os cíclicos ace alizados, D-galac osa, D-manosa, ácido L- a á ico, copoliés e es al aza , copoliés e es en bloque Resum Els poliès e s són políme s ex emadamen e sà ils que s’usen en una àmplia a ie a d’aplicacions, des de ma e ials d’al es p es acions a políme s eciclables o deg adables. La p epa ació de poliès e s a pa i de on s eno ables gene a cada egada més in e ès, an a la indús ia com al món acadèmic. En aques a Tesi s’u ili zen on s na u als pe desen olupa nous poliès e s ali à ics i a omà ics amb p opie a s millo ades, a pa i de monòme s cíclics de i a s de ca bohid a s, i.e. un àcid aldà ic ace ali za bicíclic de i a de D-galac osa, aldi ols ace ali za s bicíclics de i a s de D- galac osa i D-manosa, i un aldi ol ace ali za cíclic de i a d’àcid L- a à ic. Els nous poliès e s ali à ics de i a s d’àcid galac à ic i D-manni ol ace ali za bicíclic, que són ma e ials biodeg adables, des aquen pe p esen a una igidesa millo ada espec e als poliès e s ali à ics comunamen usa s ins al dia d’a ui, e que in luencia in a iablemen les se es p opie a s è miques i mecàniques. També es epo a l’ús de monòme s bicíclics ace ali za s de i a s de ca bohid a s pe a la p epa ació de copoliès e s poli(alquilen e e ala )s amb mic oes uc u a a l’a za , mi jançan policondensació en es a os (MP). S’u ili zen α,ω- alcanodiols lineals de di e en s longi uds, i les polime i zacions amb monòme s bicíclics es duen a e me en un ampli ang de composicions, e s que pe me en desen olupa un es udi es uc u a-p opie a s de alla . L’e ec e de la uni a eno able en les p opie a s è miques i mecàniques del poliès e depèn de quina uni a no eno able, diol o diàcid, subs i ueix. La inco po ació d’aldi ols ace ali za s augmen a l’es abili a è mica, la empe a u a de ansició í ia i el mòdul elàs ic. D’al a banda, aques s pa àme es disminueixen quan les uni a s e e àliques es subs i ueixen pe àcid galac à ic ace ali za bicíclic. Les uni a s eno ables in oduïdes a ec en ambé la deg adabili a hid olí ica i enzimà ica dels poliès e s. Mi jançan la ècnica de modi icació en es a sòlid (SSM), s’inco po en aldi ols cíclics ace ali za s a la ase amo a del poli(bu ilen e e ala ), e que augmen a la se a empe a u a de ansició í ia. Els copoliès e s esul an s p esen en una mic oes uc u a en blocs, que els p opo ciona unes p opie a s è miques supe io s espec e als copoliès e s anàlegs amb mic oes uc u a a l’a za p epa a s mi jançan MP. En aques a Tesi ambé es compa en les ca ac e ís iques i p opie a s del monòme isoso bide i els aldi ols ace ali za s bicíclics pe a la sín esi de poliès e s i a omà ics, degu a la se a p oximi a es uc u al, així com el seu ús po encial com a monòme s en policondensacions. Es des aca la majo acili a de eacció en les condicions es udiades dels aldi ols ace ali za s, i ambé s’a alua la in luència de la sime ia i la igidesa de l’es uc u a bicíclica en les p opie a s è miques dels copoliès e s. Pa aules clau: poliès e , ca bohid a s, on s na u als, monòme s cíclics ace ali za s, D-galac osa, D-manosa, àcid L- a à ic, copoliès e s a l’a za , copoliès e s en bloc ii Table o Con en s Chap e 1. Aim and ou line o his Thesis 1 Chap e 2. Polyes e s: T adi ional p oduc s and p esen bio-based endencies 13 2.1. In oduc ion 14 2.2. Types and applica ions o he moplas ic polyes e s 16 2.2.1. Alipha ic polyes e s 16 2.2.2. A oma ic polyes e s 18 2.2.3. Alipha ic-a oma ic copolyes e s 20 2.2.4. Fully a oma ic polyes e s 21 2.2.5. The moplas ic elas ome s 22 2.3. Syn he ic me hods 23 2.3.1. Mel polyme iza ion 23 2.3.2. Solid-s a e polyme iza ion 25 2.3.3. Solu ion polyme iza ion om diacyl dichlo ides 27 2.3.4. Ring-opening polyme iza ion 27 2.3.5. Enzyma ic polyme iza ion 28 2.4. Bio-based polyes e s 29 2.4.1. Polyes e s pa ially o o ally p oduced by bac e ia 29 2.4.1.1. Polylac ic acid (PLA) 29 2.4.1.2. Polyhyd ohyalkanoa es (PHAs) 30 2.4.2. Al e na i e ou es om enewable sou ces o con en ional monome s 31 2.4.3. Polyes e s om ca bohyd a e-de i ed monome s wi h modi ied p ope ies 33 2.4.3.1. Unp o ec ed aldi ols and alda ic acids 33 2.4.3.2. Acyclic O-p o ec ed aldi ols and alda ic acids 34 2.4.3.3. 2,5-Fu andica boxylic acid (FDCA) 36 2.4.3.4. Dianhyd ohexi ols and de i a i es 38 2.4.3.5. Cyclic ace alized aldi ols, aldonic and alda ic acids 47 2.5. Re e ences 49 xi Glossa y a Ma k-Houwink pa ame e Ad Dime hyl adipa e A 2,3,4-T i-O-me hyl-L-a abini ol A H A oma ic p o on A -OMe 2,3,4-T i-O-me hyl-L-a abini ol asym s Asymme ic s e ching ib a ion ATR A enua ed o al e lec ance B 1,4-Bu ylene uni s BISHET Bis-(2-hyd oxye hyl) e eph hala e bs B oad single COSY 2D 1H-1H Homonuclea NMR spec a d Double DBTO Dibu yl in oxide dd Double o double s DFT Densi y unc ional heo y dhkl B agg spacings DMF N,N-Dime hyl o mamide DMSO Dime hyl sul oxide DMT Dime hyl e eph hala e DSC Di e en ial scanning calo ime y Ð Polydispe si y δ Chemical shi (ppm) ΔHc C ys alliza ion en halpy ΔHcc Cold c ys alliza ion en halpy ΔHm Mel ing en halpy ΔHmº Mel ing en halpy o a 100% c ys alline polyme ΔT ‘Unde cooling’ alues equi ed o c ys alliza ion (ΔT= Tm-Tc) E Elas ic modulus E 1,2-E hylene uni s ε Elonga ion a b eak Endo Seconda y hyd oxyl g oups (1,4:3,6-dianhyd ohexi ols) o me hylol g oups (bicyclic ace alized aldi ols) o ien ed inside he bicyclic s uc u e EG E hylene glycol E OH E hanol E 2O Die hyl e he Exo Seconda y hyd oxyl g oups (1,4:3,6-dianhyd ohexi ols) o me hylol g oups (bicyclic ace alized aldi ols) o ien ed ou side he bicyclic s uc u e F Fu u al FA Fu u yl alcohol FDCA 2,5-Fu andica boxylic acid FTIR Fou ie ans o m in a ed spec oscopy x Galx Ace alized bicyclic non- used 2,3:4,5-di-O-me hylene s uc u e wi h D- galac o con igu a ion GPC Gel pe mea ion ch oma og aphy HETCOR 2D 13C-1H He e onuclea shi co ela ion NMR spec a HFIP 1,1,1,3,3,3-Hexa luo oisop opanol HMF Hyd oxyme hyl u aldehyde HMW High molecula weigh HPLC High pe o mance liquid ch oma og aphy [η] In insic iscosi y ICI Impe ial Chemical Indus ies IIDCA 1-Ca bon ex ended isoidide de i a i e wi h dica boxylic unc ionali y (chain ex ension a C2 and C5 o he isohexide skele on), namely isoidide dica boxylic acid IIDML 1-Ca bon ex ended isoidide de i a i e wi h wo p ima y hyd oxyl g oups (chain ex ension a C2 and C5 o he isohexide skele on), namely isoidide hyd oxyme hylene diol IR In a ed spec oscopy Is Isoso bide; 1,4:3,6-dianhyd o-D-gluci ol Isoidide 1,4:3,6-Dianhyd o-L-idi ol Isomannide 1,4:3,6-Dianhyd o-D-manni ol Isoso bide 1,4:3,6-Dianhyd o-D-gluci ol J Coupling cons an k A ami kine ic cons an K Ma k-Houwink cons an LA Lac ic acid LC Liquid c ys alline LDH Lac a e deshyd ogenase Li . Li e a u e LMW Low molecula weigh LNP Liquid ni ogen pump m In NMR spec a, mul iple peak; in WAXD measu emen s, medium in ensi y MAF Mobile amo phous ac ion Manx Ace alized bicyclic used 2,4:3,5-di-O-me hylene s uc u e wi h D-manno con igu a ion Mn Numbe -a e age molecula weigh Mp Peak molecula weigh m.p. Mel ing poin MP Mel polycondensa ion MPPBxThxyT Random copolyes e s poly(bu ylene e eph hala e-co- 2,3-di-O- me hylene-L- h ei ol e eph hala e)s, p epa ed by mel polycondensa ion M Viscosime ic molecula weigh Mw Weigh -a e age molecula weigh N Rela i e mola amoun o he dyads as ob ained om 13C NMR x i n In iso he mal c ys alliza ion s udies, A ami exponen ; in chemical mic os uc u e analysis by 13C NMR, numbe a e age sequence leng hs NaTFA-HFIP 0.05 M sodium i luo oace a e-hexa luo oisop opanol n.d. No de e mined NMP N-Me hyl-2-py olidone NMR Nuclea magne ic esonance NOE Nuclea O e hause e ec NOESY Nuclea O e hause e ec spec oscopy PBF Poly(bu ylene 2,5- u andica boxyla e) PBGalx Poly(bu ylene 2,3:4,5-di-O-me hylene-galac a a e) PBS Poly(bu ylene succina e) PBT Poly(bu ylene e eph hala e) PBTxGalxy Random copolyes e s poly(bu ylene e eph hala e-co- bu ylene 2,3:4,5- di-O-me hylene-galac a a e)s, p epa ed by mel polycondensa ion PBxGalxyT Random copolyes e s poly(bu ylene e eph hala e-co- 2,3:4,5-di-O- me hylene-galac i ol e eph hala e)s, p epa ed by mel polycondensa ion PBxIsyT Random copolyes e s poly(bu ylene e eph hala e-co- isoso bide e eph hala e)s, p epa ed by mel polycondensa ion PBxManxyS Random copolyes e s poly(bu ylene succcina e-co-2,4:3,5-di-O- me hylene-D-manni ol succina e)s, p epa ed by mel polycondensa ion PBxManxyT Random copolyes e s poly(bu ylene e eph hala e-co- 2,4:3,5-di-O- me hylene-D-manni ol e eph hala e)s, p epa ed by mel polycondensa ion PCL Poly(ε-cap olac one) PDGalx Poly(dodecame hylene 2,3:4,5-di-O-me hylene-galac a a e) PDT Poly(dodecame hylene e eph hala e) PDTxGalxy Random copolyes e s poly(dodecame hylene e eph hala e-co- dodecame hylene 2,3:4,5-di-O-me hylene-galac a a e)s, p epa ed by mel polycondensa ion PEF Poly(e hylene 2,5- u andica boxyla e) PEI Poly(e hylene isoph hala e) PE-nAd Poly(alkylene adipa e)s, he n being he numbe o me hylenes PE-nAdxGalxy Random copolyes e s poly(alkylene adipa e-co- alkylene 2,3:4,5-di-O- me hylene-galac a a e)s, he n being he numbe o me hylenes, p epa ed by mel polycondensa ion PE-nGalx Poly(alkylene 2,3:4,5-di-O-me hylene-galac a a e)s, he n being he numbe o me hylenes PET Poly(e hylene e eph hala e) PExManxyT Random copolyes e s poly(e hylene e eph hala e-co- 2,4:3,5-di-O- me hylene-D-manni ol e eph hala e)s, p epa ed by mel polycondensa ion PGA Poly(glycolic acid) PGalxT Poly(2,3:4,5-di-O-me hylene-galac i ol e eph hala e) x ii PHAs Polyhyd oxyalkanoa es PHB Poly(3-hyd oxybu y a e) PHF Poly(hexame hylene 2,5- u andica boxyla e) PHGalx Poly(hexame hylene 2,3:4,5-di-O-me hylene-galac a a e) PHH Poly(3-hyd oxyhexanoa e) PHT Poly(hexame hylene e eph hala e) PHTxGalxy Random copolyes e s poly(hexame hylene e eph hala e-co- hexame hylene 2,3:4,5-di-O-me hylene-galac a a e)s, p epa ed by mel polycondensa ion PHV Poly(3-hyd oxy ale a e) PIsT Poly(isoso bide e eph hala e) PLA Polylac ic acid PLLA Iso ac ic poly(L-lac ic acid) PManxS Poly(2,4:3,5-di-O-me hylene-D-manni ol succina e) PManxT Poly(2,4:3,5-di-O-me hylene-D-manni ol e eph hala e) PMMA Poly(me hyl me hac yla e) POF Poly(oc ame hylene 2,5- u andica boxyla e) Poly(HB-co-HH) Copolyes e poly(3-hyd oxybu y a e-co- 3-hyd oxyhexanoa e) Poly(HB-co-HV) Copolyes e poly(3-hyd oxybu y a e-co- 3-hyd oxy ale a e) POM Pola izing op ical mic oscopy PPF Poly(p opylene 2,5- u andica boxyla e) PTA Pu i ied e eph halic acid PThxT Poly(2,3-di-O-me hylene-L- h ei ol e eph hala e) PTT Poly( ime hylene e eph hala e) py Py idine θ Con ac angle in deg ees (º) R Randomness index o copolyes e s s a is ically calcula ed on he basis o he 13C NMR analysis RAF Rigid amo phous ac ion Rc Randomness index o he amo phous ac ion o copolyes e s ock Rocking ib a ion ROP Ring-opening polyme iza ion s In NMR spec a, single peak; in WAXD measu emen s, s ong in ensi y S Suga -based uni s σ Tensile s eng h SA Succinic acid SEC Size-exclusion ch oma og aphy SEM Scanning elec on mic oscopy SSM Solid-s a e modi ica ion SSMPBxGalxyT Block-like copolyes e s poly(bu ylene e eph hala e-co- 2,3:4,5-di-O- me hylene-galac i ol e eph hala e)s, p epa ed by solid-s a e modi ica ion o PBT x iii SSMPBxManxyT Block-like copolyes e s poly(bu ylene e eph hala e-co- 2,4:3,5-di-O- me hylene-D-manni ol e eph hala e)s, p epa ed by solid-s a e modi ica ion o PBT SSMPBxThxyT Block-like copolyes e s poly(bu ylene e eph hala e-co- 2,3-di-O- me hylene-L- h ei ol e eph hala e)s, p epa ed by solid-s a e modi ica ion o PBT SSP Solid-s a e polycondensa ion s S e ching ib a ion Sym s Symme ic s e ching ib a ion T iple peak T Te eph hala e uni s 0 Onse c ys alliza ion ime 1/2 Hal -c ys alliza ion ime ºT5% In TGA, empe a u e a which 5% weigh loss was obse ed TBT Ti anium (IV) e abu oxide Tc C ys alliza ion empe a u e Tcc Cold c ys alliza ion empe a u e Td o maxTd In TGA, empe a u e o maximum deg ada ion a e TFA T i luo oace ic acid TFA-d Deu e a ed i luo oace ic acid Tg Glass- ansi ion empe a u e TGA The mog a ime y THF Te ahyd o u an Th-OMe 2,3-Di-O-me hyl-L- h ei ol Thx Ace alized cyclic 2,3-di-O-me hylene s uc u e wi h L- a a ic acid con igu a ion Tm Mel ing empe a u e TMS Te ame hylsilane TPEs The moplas ic elas ome s SSM SSM eac ion ime U One uni (U) was de ined as ha amoun o enzyme which ca alyzed he elease o a y acid om iglyce ides a he a e o 1 µmol·min-1.  Wa enumbe (cm-1) w In WAXD measu emen s, weak in ensi y W In TGA, emaining weigh a 600 ºC WAXD Wide angle X- ay di ac ion X Mola composi ion de e mined by 1H NMR Xc C ys allini y index Xy 2,3,4-T i-O-me hylxyli ol Xy-OBn 2,3,4-T i-O-benzylxyli ol XRD X-Ray di ac ion 1 CHAPTER 1 AIM AND OUTLINE OF THIS THESIS In oduc ion The de elopmen o bio-based polyme s is nowadays a ac ing a g ea deal o in e es , due o he high p ice and u u e deple ion o ossil uel s ocks, oge he wi h conce ns ega ding en i onmen al sus ainabili y. Howe e , his app oach is no new; bio- based polyme s ha e a his o y o mo e han a cen u y, much longe han pe ochemical polyme s. In he 19 h cen u y, na u al aw ma e ials such as casein, shellac, gum, na u al ubbe , and cellulose we e chemically modi ied o con e hem in o use ul polyme s wi h new p ope ies. An impo an objec i e was o con e he in usible and equen ly insoluble na u al s ocks in o ma e ials capable o being p ocessed. The i s ho n-like plas ic ma e ial was galali h, p oduced by eac ing casein om milk wi h o maldehyde o o m a s i he mose esin esembling s one. Al hough he biodeg adable and wa e - soluble galali h was no moldable, shee s could be p oduced, hus enabling dyeing and machining. The la ex o B azilian ubbe ees was collec ed, coagula ed, d ied, and ulcanized wi h sul u o p oduce indus ial ubbe o making i es. When he highly lammable and explosi e ni ocellulose, ob ained by ni a ion o cellulose and used as smokeless gunpowde , was plas icized wi h campho , i was ende ed he moplas ic. Bio- based ni ocellulose, ma ke ed as Pa kesine and Cellulloid, was a he haza dous owing o i s explosi e cha ac e . Ne e heless, moldable ni ocellulose became a success ul subs i u e o i o y and was used o making billia d balls, hus sa ing he li es o housands o elephan s. Pho og aphic ilms we e possible a hose imes hanks o he use o ni ocellulose as suppo ing ilm o he sil e ni a e emulsion, al hough hey ep esen ed a se e e i e and sa e y haza d o cinemas. Since hen, nume ous new compounds de i ed om enewable esou ces ha e been de eloped. One example is e hylene which was syn hesized by he dehyd a ion o bio-based e hanol in he 1940s. Also in ha ime he p o ein casein was used o pain s and glues and la e on, in o mula ion wi h o maldehyde, as plas ic used o p oduc s like bu ons, kni es and le e opene s. Soy p o ein was eac ed wi h o maldehyde and co- condensed wi h phenol and u ea; hese soy plas ics we e used o p oduce se e al Chap e 1 2 au omo i e pa s such as s ee ing wheels, glo e-box doo s and in e io im. Shellac was p oduced by ex ac ion o he na u al polyme exc e ed by he shell louse, and was used o pain s and a nish nex o small solid a icles. Also egene a ed cellulose, e.g. in he o m o cellophane ilm o man-made cellulose ibe s, was de eloped in hose imes and has been used in a wide ange o applica ions, such as appa el, ood (e.g. o sausages) and non-plas ics (e.g. a nishes). Howe e , many o he in en ions in he 1930s and 1940s s ayed in labo a o y and we e ne e used o comme cial p oduc ion. The main eason was he la ge-scale indus ial use o pe ochemical eeds ock o manu ac u e a g ea a ie y o syn he ic polyme s since 1950s. Exploi a ion o oil and gas as ossil aw ma e ials o he chemical indus y and polyme p oduc ion g ea ly imp o ed cos - e ec i eness and simpli ied manu ac u ing o mac omolecula ma e ials. The a ac i e combina ion o low cos wi h acile p ocessing ep esen ed he key ea u e o pe ochemical polyme s. Also some bio-based p oduc s, such as man-made cellulose ibe s, con inued being p oduced bu hei p oduc ion did no g ow a he a e o he newly eme ging pe ochemical p oduc s. On he o he hand, s a ch de i a i es used as pape and ex ile auxilia ies had a long pe iod o g ow h and a e s ill used nowadays. The oil p ice shocks o he 1970s led o enewed in e es in o he possibili ies o e ed by non-pe ochemical eeds ock. Howe e , some ime a e he in e es in pe ochemical polyme s con inued g owing. D i en by conce ns abou apidly inc easing amoun s o was e, in he 1990s new ecycling echnologies enabled e ec i e euse o polyme p oduc s ha had comple ed hei i s li ecycle. Bio-based polyme s ha e expe ienced a enaissance in he las ew decades. Many new polyme s om bio-based eeds ock ha e been de eloped, e.g. polylac ic acid (PLA) om ca bohyd a es. Today, public conce ns abou en i onmen , clima e change and limi ed ossil uel esou ces ha e become mo e impo an d i e s. The u iliza ion o ossil uels in he manu ac u e o plas ics accoun s oday o abou 7% o wo ldwide oil and gas. I is an icipa ed ha his esou ce will be deple ed in he coming decades; u he mo e, he p ice o oil has inc eased apidly in ecen yea s, and i is subjec o unp edic able socio-poli ical in luences. While he use o ossil ese es o anspo a ion and hea ing is ce ainly he mos se ious conce n, he chemical indus y will also be aced wi h he p oblema ic issue associa ed o he use o an essen ially non- enewable eeds ock o he majo i y o hei p oduc s. Polyme s based on enewable esou ces a e e y a ac i e, no only o coming om na u al eeds ock, bu also o he bene i s hey p o ide om was e ea men poin o iew. In ac , many o he p oduc s de i ed om Aim and ou line o his Thesis 3 enewable esou ces can be deg aded in he p esence o mic oo ganisms, he e o e being able o ba le agains he p oblem o inc easing amoun s o was e and limi ed land ill capaci y. In addi ion, polyme s de i ed om na u al sou ces no only p o ide impo an en i onmen al bene i s, bu in some cases a e also biocompa ible ma e ials, p ope y essen ial o i s applica ion in biomedicine. Figu e 1.1. Raw ma e ials used by he chemical indus y in hys o ical pe spec i e. Renewable eeds ock (a); coal (b); oil and gas (c). Sou ce: Lich en hale , F.W. Ca bohyd a es as O ganic Raw Ma e ials. Ullmann’s Encyclopedia o Indus ial Chemis y, 2010. Ca bohyd a es a e he mos abundan na u al o ganic compounds in plan s, o igina ed as p oduc o pho osyn hesis, an endo he mic eac ion educing ca bon dioxide which equi es he ene gy o he ligh and he pigmen chlo ophyll. Ca bohyd a es a e an impo an sou ce o me abolic ene gy, bo h o humans and animals. Na u e p oduces annually abou 140·109 ons o ca bohyd a es om ca bon dioxide and wa e , making hese compounds he mos abundan o ganic ma e ial on ea h. Humani y only uses 4% o his huge amoun o ood and non- ood pu poses. They can be looked he e o e as an ex ao dina y sou ce o chemicals capable o p o iding a wide di e si y o building blocks o polycondensa ion polyme s. Thus, he de elopmen o ca bohyd a e-based polyme s has he po en ial o educe he amoun o pe oleum consumed in he chemical indus y and also o open new high- alue-added ma ke s o ag icul u e. Howe e , he e a e only a ew examples o ca bohyd a e-de i ed plas ics comme cially a ailable, which is mos ly due o he s ill high cos o hese ma e ials compa ed o pe oleum-based coun e pa s. Ano he se e e limi a ion in he use o ca bohyd a es as a sou ce o monome s o he syn hesis o linea polycondensa es is hei inhe en mul i unc ionali y; ce ain p e ious Chap e 1 4 ea men s a e usually equi ed o a oid he o ma ion o highly c oss-linked polyme s. The mos commonly used s a egy is blocking he exceeding unc ional chemical g oups wi h s able p o ec ing g oups, and hus e aining only wo eac i e unc ional g oups o ca y ou linea polycondensa ion. P o ec ion o he exceeding hyd oxyl g oups as me hoxy e he s has led o ob aining hyd ophilic linea polyes e s, which in some cases we e also biodeg adable. Howe e , gi en he lexibili y o he acyclic molecula s uc u e o hese ca bohyd a e-based monome s, he esul ing polyes e s ha e a glass- ansi ion empe a u e, mechanical s eng h and s i ness gene ally es ic ed. Isoso bide, along wi h hei wo less accessible 1,4:3,6-dianhyd ohexi ol s e eoisome s isomannide and isoidide, a e cu en ly d awing a g ea in e es in he polyme science ield as bio-based monome s able o p o ide enhanced s i ness in o he polyme chain hey a e inco po a ed. These h ee isohexides a e composed o wo used e ahyd o u an ings, wi h wo seconda y hyd oxyl g oups emaining ee o eac ion. Because o hei used bicyclic s uc u e, 1,4:3,6-dianhyd ohexi ols a e able o inc ease he glass- ansi ion empe a u e o common alipha ic and a oma ic polyes e s. Ne e heless, he main sho coming o isoso bide and i s isome s is he limi ed eac i i y o hei seconda y hyd oxyl g oups; in ac , his ea u e se iously hampe s he polycondensa ion eac ion in he mel , so polyes e s om 1,4:3,6-diahyd ohexi ols ob ained by his me hod display a he limi ed molecula weigh s. Aim and scope o his Thesis In his Thesis, he po en ial use o cyclic ca bohyd a e-based monome s o p epa e polyes e s is highligh ed. Polyes e s a e ex emely e sa ile polyme s which can be used in a wide a ie y o applica ions anging om high pe o mance ma e ials o ecyclable and deg adable polyme s. The p epa a ion o polyes e s om enewable eeds ock is cu en ly ecei ing inc easing a en ion in he indus y and academia. Fo ins ance, bio-based succinic acid o alipha ic polyes e p epa a ion is indus ially p oduced nowadays by anae obic e men a ion using a ious ypes o mic oo ganisms and na u al subs a es. Also he bicyclic diol monome isoso bide, which is p epa ed by dehyd a ion o D-glucose coming om ce eal s a ch, is al eady a ailable a indus ial scale oday. This Thesis is speci ically add essed o he de elopmen o alipha ic and a oma ic polyes e s wi h enhanced p ope ies made om ca bohyd a e-based cyclic Aim and ou line o his Thesis 5 ace alized monome s. The main ad an age o cyclic ace alized diols compa ed o 1,4:3,6- diahyd ohexi ols is ha in he o me case, he wo hyd oxyl g oups ee o eac ion a e p ima y and hus display enhanced eac i i y compa ed o hose o 1,4:3,6- diahyd ohexi ols. The aim o he Thesis is o p epa e, cha ac e ize and e alua e he basic p ope ies o linea alipha ic and a oma ic polyes e s made om cyclic ace alized monome s de i ed om ca bohyd a es, namely a bicyclic ace alized alda ic acid de i ed om D-galac ose, bicyclic ace alized aldi ols de i ed om D-galac ose and D-mannose, and a cyclic ace alized aldi ol de i ed om L- a a ic acid. An alda ic acid is an aldose de i a i e which has bo h he p ima y hyd oxyl and he ca bonyl g oups oxidized o ca boxylic g oups. Alda ic acids a e use ul o ob ain linea polyes e s by eac ion wi h diols p o ided ha all he seconda y hyd oxyl g oups a e duly p o ec ed. In his wo k, he seconda y hyd oxyl g oups a e p o ec ed as me hylene ace als, leading o ca bohyd a e-based diacids wi h a cyclic s uc u e. An aldi ol is an aldose de i a i e which has he ca bonyl g oup educed o hyd oxyl g oup. The p o ec ion o he seconda y hyd oxyl g oups, lea ing he wo p ima y hyd oxyl g oups ee o eac ion, makes aldi ols usable as monome s o he p oduc ion o linea polyes e s by eac ion wi h dica boxylic acids. In his wo k, he seconda y hyd oxyl g oups a e p o ec ed as me hylene ace als, leading o ca bohyd a e-based diols wi h a cyclic s uc u e. The syn he ic p ocedu es ollowed o he p epa a ion o he ou ca bohyd a e- based monome s used in his Thesis a e depic ed in Schemes 1.1, 1.2 and 1.3, summa ized below and u he de ailed in Annex A. Scheme 1.1. Syn hesis o dime hyl 2,3:4,5-di-O-me hylene-galac a a e and 2,3:4,5-di-O-me hylene- galac i ol om D-galac ose. Chap e 1 12 13 CHAPTER 2 POLYESTERS: TRADITIONAL PRODUCTS AND PRESENT BIO-BASED TENDENCIES Summa y: Polyes e is he gene al name gi en o a amily o polyme s which con ain he es e g oup in hei cons i u ional epea ing uni . Since he pionee ing expe imen s o Ca o he s in he 1930s, polyes e s ha e ound ex ensi e use in a wide ange o applica ions, including enginee ing plas ics, high pe o mance ma e ials, and ecyclable and deg adable polyme s, due o he eno mous a ie y o s uc u es and p ope ies which cons i u e he polyes e amily. This in oduc o y chap e e iews some aspec s o polyes e s, such as hei main ypes and applica ions as well as hei syn he ic me hods. I also desc ibes he p esen bio-based endencies ega ding polyes e p epa a ion. Al e na i e ou es om na u al eeds ock o p oduce monome s which a e con en ionally ob ained om pe ochemical sou ces a e desc ibed; his app oach en ails no di e ences in e ms o ma e ial p ope ies be ween bio-based polyes e s and hei pe ochemical coun e pa s since hey sha e he same chemical s uc u e. Finally, he use so a o ca bohyd a e-de i ed monome s o p oduce polyes e s wi h modi ied p ope ies is e iewed; his includes acyclic monome s as well as cyclic monome s such as 2,5- u andica boxylic acid and 1,4:3,6-dianhyd ohexi ols. Chap e 2 14 2.1. In oduc ion Polyes e s a e polyme s in which he main chain is composed o alipha ic o a oma ic moie ies R1 and R2 linked oge he by es e g oups (Scheme 2.1). Scheme 2.1. Gene al o mula o polyes e s. The polyes e amily is ex emely la ge and, depending on he na u e o R1 and R2, exhibi s an eno mous a ie y o s uc u es, p ope ies and he e o e, applica ions. I has been known since he ea ly 19 h cen u y ha hea ing ca boxylic polyacids wi h glyce ol esul ed in esinous compounds. In he 1910-1920s, he Gene al Elec ic Company led ex ensi e esea ch on he chemis y o ph halic anhyd ide-glyce ol eac ion and de eloped he echnology o alkyd esins (glyp al esins), which a e essen ially polyes e s o ph halic anhyd ide, glyce ol, and monoca boxylic unsa u a ed a y acids. These esins a e s ill used in coa ings, a nishes and pain s. Howe e , he mode n his o y o polyes e s began when Ca o he s pe o med expe imen al s udies on eac ions be ween alipha ic diacids and diols and es ablished he ela ionships be ween deg ee o polyme iza ion, con e sion, unc ionali y and gel poin , ha is, he base ela ionships o s ep-g ow h polyme iza ion (Ca o he s, 1929, 1931 and 1936; Ca o he s and A in, 1929; Ca o he s and Do ough, 1930; Ca o he s e al., 1932). Howe e , hese polyes e s had low mel ing poin and we e sensi i e o hyd olysis, and he e o e hey could no compe e wi h alipha ic polyamides (nylons), also disco e ed in he 1930s by Ca o he s a he DuPon Company. To inc ease he polyes e mel ing poin and o app oach he he momecanical p ope ies ob ained by nylons, i was necessa y o s i en he polyes e chain by using igid a oma ic monome s ins ead o lexible alipha ic ones. In he ea ly 1940s, high mel ing poin ibe - o ming polyes e s om e eph halic acid and alipha ic diols we e syn hesized by Whin ield in he labo a o ies o he Calico P in e s Associa ion in he Uni ed Kingdom. A e Wo ld Wa II he pa en igh s on hese a oma ic polyes e s we e sha ed be ween Impe ial Chemical Indus ies (ICI) and DuPon , and se e al membe s o his amily became, and a e s ill oday, majo comme cial polyme s (Whin ield and Dickson, 1946). Poly(e hylene e eph hala e) (PET) is now one o he mos p oduced Polyes e s: T adi ional p oduc s and p esen bio-based endencies 15 polyme s, p ima ily o ex ile and packaging applica ions. Poly(bu ylene e eph hala e) (PBT) inds uses as solid-s a e molding esin. Poly( ime hylene e eph hala e) (PTT), al hough was desc ibed in Whin ield’s o iginal pa en , is a newcome in he comme cial polyes e amily and has ound i s i s applica ions in he ex ile indus y. A new ype o he mose ing esin, based on unsa u a ed polyes e s, was de eloped a he end o he 1930s (Ellis, 1937). Unsa u a ed polyes e s we e syn hesized by eac ing mix u es o sa u a ed and unsa u a ed diacids o anhyd ides wi h alipha ic diols. The he mose ing esin was ob ained by dissol ing hese polyes e s in an unsa u a ed monome , such as s y ene, capable o unde going ee- adical copolyme iza ion wi h he unsa u a ions in polyes e chains. The liquid esin was ans o med in o a igid and insoluble c oss-linked polyme ne wo k a e adical polyme iza ion in he p esence o hea o ca alys s. Unsa u a ed polyes e esins ound hei i s applica ions in combina ion wi h glass ibe s o p o ec i e ada domes du ing Wo ld Wa II, and a e now one o he mos impo an ma ix esins o glass- ibe - ein o ced composi e ma e ials (F ade and Tessie , 2003). In he la e 1950s and he 1960s, low-molecula weigh (Mn= 1,000-3,000 g·mol-1) hyd oxyl-ended alipha ic polyes e s we e used as mac omonome s in he syn hesis o polyu e hane elas ome s and lexible oams by eac ion wi h diisocyana es. Al hough alipha ic polyes e s we e he i s s ep-g ow h polyme s ully cha ac e ized, hey did no ind comme cial applica ions un il hen. In he 1970s, polyes e e he block copolyme s we e comme cialized by Dupon unde he adename Hy el; hese copolyme s exhibi ed he cha ac e is ics o he moplas ic elas ome s (Holden e al., 1996). Du ing his pe iod a en ion was also ocused on high-pe o mance ully a oma ic polyes e s; he comme cial in oduc ion o he i s one, he amo phous poly(bisphenol-A isoph hala e- e eph hala e) (Union Ca bide’s A del), ook place in he mid 1970s (Dean e al., 1989). Despi e hei high cos , liquid c ys alline he mo opic polyes e s, such as poly(6-hyd oxy-2-naph hoic acid-co-4-hyd oxybenzoic acid) (Ticona’s Vec a), desc ibed a he end o he 1970s (Calundann, 1977), ound and s ill ha e a numbe o applica ions in high- echnology ma ke s. In he 1990s, en i onmen al conce ns began o be gaining g ound (Lich en hale , 2010). The e sa ili y o he es e linkage, able o unde go hyd olysis in some condi ions, makes polyes e s he polyme s o choice o ul ill he inc easing demand o ecyclable and biodeg adable polyme s (Albe sson and Va ma, 2003). This has esul ed in a enewed in e es in alipha ic polyes e s, such as poly(lac ones), poly(lac ides) o Chap e 2 16 copolyes e s con aining alipha ic moie ies. PET p oduc ion is also s ongly d i en by he demand o ecyclable polyme s. 2.2. Types and applica ions o he moplas ic polyes e s Polyes e s a e one o he mos e sa ile classes o polyme s e e p oduced, co e ing a wide ange o p ope ies and applica ions. As desc ibed abo e, polyes e polyols a e used in he syn hesis o polyu e hane elas ome s and lexible oams by eac ion wi h diisocyana es; hey a e also used o o he applica ions such as coa ings, pain s, sealan s and adhesi es. Unsa u a ed polyes e s ha e ound ex ensi e use o yield he mose ing polyes e esins wi h a wide ange o p ope ies, and can be also ein o ced wi h glass ibe s o illed wi h la ge amoun s o low-cos ille s. Fu he mo e, he moplas ic polyes e s a e used as ibe s, enginee ing he moplas ics and high-pe o mance polyme s. The main p ope ies and applica ions o he moplas ic polyes e s which ha e a close ela ion wi h his Thesis a e discussed below. 2.2.1. Alipha ic polyes e s The es e linkage can be easily clea ed by hyd olysis unde alkaline, acid, o enzyma ic ca alysis. This ea u e makes alipha ic polyes e s e y a ac i e o hose applica ions which equi e deg ada ion o he polyme s, i.e. biomedical de ices and en i onmen ally deg adable polyes e s. Poly(lac ic acid) (PLA) is an alipha ic polyes e whose monome is p oduced om ca bohyd a es and is deg aded by mic oo ganisms o gene a e ul ima ely CO2 and H2O. This polyme can be he e o e conside ed ully en i onmen ally- iendly and i is an excellen ep esen a i e o wha is oday so-called a g een polyme (Scheme 2.2). PLA has ound use in medical applica ions and i is ecei ing in e es as a ma e ial sui able o eplacing con en ional commodi y plas ics in a wide di e si y o applica ions (Tokiwa and Ja e a , 2004). Polyes e s: T adi ional p oduc s and p esen bio-based endencies 17 Scheme 2.2. Cycle o poly(lac ic acid). Bio eso bable implan s, o ins ance o hopedic ixa ions o su u es, a e de ices designed o slowly deg ade in he body a e implan a ion, so ha a second su gical in e en ion is no equi ed o implan emo al a e healing. Polyes e s and copolyes e s o lac ic acid and glycolic acid ha e been used as bio eso bable su u es since he 1960s. These polyes e s gi e no oxic o in lamma o y esponse, can be s e ilized, and a e slowly and comple ely hyd olyzed in o na u al me abolic by-p oduc s ha a e elimina ed by he body. O he alipha ic polyes e s such as poly(ε-cap olac one), poly(dioxanone) and poly( ime hylene ca bona e) ha e also been used o his applica ion (Middle on and Tip on, 2000). Bio eso bable polyme s can be p ocessed by con en ional me hods such as injec ion-molding, comp ession-molding and ex usion, and s e iliza ion is achie ed by i adia ion o by exposu e o e hylene oxide. They a e used in wound closu e (su u es, s aples), os eosyn he ic ma e ials (pins, sc ews, ods, bone pla es), ca dio ascula su ge y (s en s, g a s), and in es inal su ge y (anas omosis ings) (Ikada and Tsuji, 2000). They also ind applica ion as ma ix ma e ials o implan ed d ug elease de ices o d ug-con aining mic osphe es o mic ocapsules (A shady, 1991). The use o en i onmen ally biodeg adable ha mless polyme s, which disappea a e a ew weeks o mon hs in soil, is an elegan way o dealing wi h solid was e disposal p oblem. Poly(ε-cap olac one) has been p oposed as a soil-deg aded con aine ma e ial, wi h applica ions o g owing and ansplan ing ees as a hin-walled ee sedling con aine (Ragha an, 1995). In addi ion, i s blends wi h s a ch and de i a i es ha e been Chap e 2 18 used in shopping bags (Da wis e al., 1998). Du ing he las ew yea s, a numbe o companies ha e pu biodeg adable polyme s on he ma ke ; almos all hese polyme s a e polyes e s o copolyes e s. Fo ins ance, copolyes e s o poly(bu ylene succina e), poly(bu ylene adipa e) and poly(e hylene succina e) ha e been comme cialized unde he ade ma k o Bionolle. The po en ial applica ions o alipha ic polyes e s in injec ion- molded a icles (cu le y, b ushes), ubula ilms (compos ing bags, shopping bags), lexible packaging, ood ay, cosme ic bo les and be e age bo les ha e been p oposed, al hough o some o hese applica ions he pe o mance o he exis ing g ades should be imp o ed. The chemical s uc u es o some commonly used alipha ic polyes e s a e depic ed in Scheme 2.3. Scheme 2.3. Chemical s uc u e o some common alipha ic polyes e s. 2.2.2. A oma ic polyes e s In e ms o olume and economic impo ance, he moplas ic polyes e s a e domina ed by poly(e hylene e eph hala e) (PET); his polyes e accoun s o 8% o he global polyme p oduc ion (Rappapo , 2010). The chemical s uc u e o PET, oge he wi h o he a oma ic polyes e s, is depic ed in Scheme 2.4. PET has expe ienced an eno mous de elopmen in ibe s and molding esins, and has ound ex ensi e use in ood packaging and bo le ma ke s o glass eplacemen , whe e i s capabili y o being ecycled is a supplemen a y o ce d i ing PET consump ion. Fibe s a e he la ges end use o PET; he wo ld p oduc ion o PET ibe s su passed ha o nylon ibe s in he beginning o he 1970s and has eached a le el close o ha o co on (Al un and Ulcay, 2004). The g ow h o PET ibe s p oduc ion has been caused by i s low p oduc ion cos s and hei abili y o be blended wi h na u al ibe s such as co on. PET esins, which Polyes e s: T adi ional p oduc s and p esen bio-based endencies 19 cons i u e he second la ges applica ion o PET, a e mainly used o he packaging ield, in ehea s e ch blow-molded bo les o ca bona ed and non-ca bona ed so d inks and wa e , and in ood and cosme ics con aine s. PET esins a e also used in shee he mo o ming applica ions, and as glass- ibe ein o ced esin o injec ion-molding applica ions. Due o a slow c ys alliza ion a e in he uno ien ed s a e bu apid c ys alliza ion upon o ien a ion, PET is e y sui able o he biaxial ilm o ien a ion p ocess. In his p ocess he amo phous ilm ob ained a e ex usion and quenching is successi ely d awn in wo o hogonal di ec ions, leading o s ess-induced c ys alliza ion wi h biaxial o ien a ion o polyme chains in he ilm plane. The esul ing anspa en ilm has app oxima ely 50% c ys allini y and exhibi s excellen he mal, mechanical and elec ical p ope ies (F ade and Tessie , 2003). PET ilm is he base ilm o some pho og aphic ilms and magne ic apes; i is also used as dielec ic ilm in capaci o s. Scheme 2.4. Chemical s uc u e o some common a oma ic polyes e s. Poly(bu ylene e eph hala e) (PBT) is mainly used as glass- ibe ein o ced enginee ing he moplas ic, al hough PBT ibe s can also be made. PBT c ys allizes much mo e apidly han PET and does no equi e nuclea ing agen s o ex usion and injec ion molding applica ions; PBT c ys allizes apidly in mold a oom empe a u e. Mo eo e , due o a lowe mel ing poin han PET, i can be molded a compa a i ely lowe empe a u e (Gallucci and Pa el, 2004). This pe mi s as p ocessing and apid p oduc ion cycles. Howe e , la ge olumes and lowe p ices make PET a se ious PBT compe i o o esin applica ions. Poly( ime hylene e eph hala e) (PTT) was al eady men ioned in Whin ield’s o iginal pa en ha desc ibed PET and PBT (Whin ield and Dickson, 1946). Howe e , no economically iable ou e o 1,3-p opanediol monome was a ailable un il he 1990s when Shell de eloped a ou e based on e hylene oxide hyd o o myla ion (D en , 1992) and Degussa a ou e based on ac olein hyd a ion/hyd ogena ion (B ei kop , 1991). PTT ibe s p esen a combina ion o p ope ies, including esilience, so ness o ouch and Chap e 2 20 dyeabili y which makes hem e y a ac i e o he ab ic, ca pe and appa el ma ke s. PTT is in ended o compe e o ilm and enginee ing he moplas ic applica ions wi h PET, PBT and polyamides. 2.2.3. Alipha ic-a oma ic copolyes e s Alipha ic polyes e s can be deg aded unde ela i ely mild condi ions, and a e biodeg adable p oduc s. Howe e , hei he mal and mechanical p ope ies a e o en limi ed and exclude hese ma e ials om many applica ions. On he con a y, a oma ic polyes e s a e dis inguished by displaying an excellen pa e n o physical p ope ies; ne e heless, hey a e s ongly esis an o hyd olysis as well as o bac e ial and ungal a ack, and usually emain unal e ed in he en i onmen . T ying o combine bo h he excellen ma e ial p ope ies o a oma ic polyes e s and he po en ial biodeg adabili y o he alipha ic ones, a la ge numbe o alipha ic-a oma ic copolyes e s ha e been de eloped du ing he las decades, and some p oduc s ha e been ecen ly comme cialized on a scale o a ew housand ons pe yea (Mülle , 2005). A a ie y o andom copolyes e s made om a mix u e o e eph halic acid and se e al alipha ic diacids wi h di e en diols ha e been p epa ed by mel polycondensa ion (Wi e al., 1994, 1996 and 1997; A ani and B isse, 1999; Naga a e al., 2000; Ki and Pa k, 2001). In he ange be ween 40 and 50 mol% o e eph halic acid ( e e ed o he acid componen s), andom copolyes e s combine su icien biodeg adabili y wi h adequa e echnical p ope ies (Mülle , 2005). Fu he mo e, eac i e blending o homopolyme s is ano he me hod o p oduce alipha ic-a oma ic copolyes e s wi h in e media e p ope ies. A oma ic homopolyes e s such as PET and PBT ha e been eac ed by his echnique wi h alipha ic homopolyes e s like poly(bu ylene succina e), poly(bu ylene adipa e), poly(ε-cap olac one), poly(lac ic acid) and poly(glycolic acid) (Tokiwa and Suzuki, 1981; Chiellini e al., 1996; Iwamo o and Towika, 1994; Kim and Pa k, 1999; Kin e al., 2003). The alipha ic-a oma ic copolyes e s ob ained by hea ing he homopolyes e s in he mol en s a e ha e a blocky chemical mic os uc u e. Se e al alipha ic-a oma ic copolyes e s a e nowadays comme cialized by di e en companies. Eco lex, p oduced by BASF (Wa zelhan e al., 1996a and 1996b), and Eas a Bio, p oduced by Eas man (Oh a e al., 1995), a e copolyes e s om Polyes e s: T adi ional p oduc s and p esen bio-based endencies 21 e eph halic acid, adipic acid and 1,4-bu anediol. These ma e ials a e sui able o biowas e bags and ilms o ho icul u e, ag icul u e, ood packaging and household applica ions. Biomax (DuPon ) is, acco ding o he p oduce , a s anda d PET wi h addi ion o special monome s o allow deg ada ion o ake place, wi h applica ions in pape coa ings, disposable cu le y, he mo o mable cups and ays, and ilms (Gallaghe e al., 1992a, 1992b and 1995). I e Chemicals p oduces alipha ic-a oma ic copolyes e s made om e eph halic acid, adipic acid, succinic acid, e hylene glycol and/o 1,4-bu anediol, wi h applica ions such as ag icul u al ilms and plas ic bags (Chung e al., 2000, 2001a and 2001b). 2.2.4. Fully a oma ic polyes e s This class comp ises amo phous high-Tg copolyes e s, known as amo phous polya yla es, and semic ys alline polyes e s ha o en exhibi aniso opic liquid c ys alline mel s. Copolyes e s o bisphenol A and iso- and e eph halic acid (Scheme 2.5) a e amo phous enginee ing he moplas ics wi h excellen hea and ul a iole ligh esis ance (Dean e al., 1989). Thei amo phous mo phology impa s on hem p ope ies o anspa ency and dimensional s abili y (Mahajan e al., 1996). Amo phous polya yla es ind applica ions o injec ion-molded pa s in au omo i e, elec onics, sa e y and building equipmen ; o example, headligh housings, i e helme s, ace shields, and anspa en ex e io pa s such as sola ene gy componen s and glazing. Scheme 2.5. Chemical s uc u e o andom copolyes e s o bisphenol A and iso- and e eph halic acid. Liquid c ys alline (LC) polyes e s a e made om igid pa a-o ien ed monome s such as 4-hyd oxybenzoic acid, hyd oquinone, e eph halic acid, o 2,6-hyd oxynaph hoic acid (Calundann, 1977). They exhibi a LC mesophase in he mol en s a e, usually a nema ic one; due o high s i ness, polyme chains end o line up pa allel o each o he , ins ead o o ming andom coils and iso opic mel s. This s uc u e is e ained in he Chap e 2 28 2.3.5. Enzyma ic polyme iza ion Polyes e s can be also ob ained by enzyme-ca alyzed polyme iza ion. Enzymes a e p o eins which exhibi a high ca aly ic e iciency and speci ici y o a gi en chemical eac ion. Lipases and es e ases belong o a class o enzymes e e ed o as hyd olyases which speci ically ca alyze he in i o hyd olysis o es e s. These enzymes, mainly lipases, we e also ound o ca alyze a numbe o in i o es e i ica ion and polyes e i ica ion eac ions in o ganic medium (Kobayashi, 1999). Enzyme-ca alyzed polyes e i ica ions a e ca ied ou a 20-80 ºC in solu ion o in he bulk using ee o immobilized enzymes, which a e usually emo ed om eac ion medium a he end o he eac ion. Sol en hyd ophobici y plays an impo an ole in enzyma ic ac i i y, pa icula y o lipases which no mally ac a oil-wa e in e aces in li ing cells (B ady e al., 1990). The bes eac i i y is usually ound o hyd ophobic sol en s such as hexane, oluene, diisop opyle he o diphenyle he . Hyd ophilic pola sol en s such as DMSO o me hanol lead o signi ican modi ica ions in enzyme con o ma ion and he e o e o a d ama ic dec ease in enzyme ac i i y (Lalo e al. 1996). Polyes e s ha e been ob ained in o ganic medium by polyes e i ica ion o hyd oxy acids (Shuai e al., 1999), hyd oxy es e s (Gu man e al., 1997), s oichiome ic mix u es o diols and diacids (Binns e al., 1998 and 1999), diols and dies e s (Mezoul e al., 1995 and 1996; Be kane e al., 1997) and cyclic anhyd ides (Kobayashi and Uyama, 1993). Since lipases also ca alyze he e e se eac ion (i.e. hyd olysis o alcoholysis o polyes e ), lipase-ca alyzed polyes e i ica ions can be ega ded as equilib ium polycondensa ions. Va ious me hods ha e been employed o emo e he eac ion by-p oduc , wa e o alcohol, in o de o displace he equilib ium owa d he o ma ion o polyes e : addi ion o molecula sie es, Dean-S a k dis illa ion o oluene-wa e azeo ope, o bubbling ine gas in eac ion medium. In he case o eac ions ca ied ou wi hou sol en , acuum can be applied o dis ill o he by- p oduc , i.e. wa e o alcohol. The use o inyl es e s is a con enien way o displace es e i ica ion equilib ium, since he heo e ical by-p oduc , inyl alcohol, au ome izes in o ace aldehyde, which canno pa icipa e in he e e se eac ion (Uyama e al., 1999). Ac i a ed es e s such as 2,2,2- i uo oe hyl, 2-chlo oe hyl and 2,2,2- ichlo oe hyl es e s ha e been epo ed o yield high-molecula weigh polyes e s (Linko e al., 1995; Wang e al., 1996). The enzyma ic syn hesis o polyes e s is mainly used o he p epa a ion o soluble o low-mel ing poin polyes e s, mainly alipha ic ones. Al hough he syn hesis o some a oma ic polyes e s o isoph halic acid has also been epo ed, lipases exhibi a e y low ca aly ic ac i i y o igid a oma ic monome s such as e ep hala es o diphenols (Wu e al., 1998; Rodney e al., 1999). Polyes e s: T adi ional p oduc s and p esen bio-based endencies 29 2.4. Bio-based polyes e s 2.4.1. Polyes e s pa ially o o ally p oduced by bac e ia 2.4.1.1. Polylac ic acid (PLA) Polylac ic acid (PLA) is an alipha ic polyes e used in biomedical applica ions such as su u es, s en s, den al implan s, ascula g a s, bone sc ews and pins (Albe sson and Va ma, 2003). I has also been in es iga ed as a ec o o d ug deli e y, o example in he long- e m deli e y o an imic obial d ugs, con acep i es and p os a e cance ea men s, and as a sca old ma e ial o suppo cell and issue g ow h (Williams, 2007). Mo eo e i is also used o ood packaging and bo le packaging o milk, wa e and juices. Fo he PLA indus y, lac ic acid (LA) wi h high op ical pu i y o o e 98-99% o L-LA is equi ed; D-LA is no desi able o ood, d ink and biomedical applica ions due o he me abolic p oblems ha D-LA may cause. The chemical s uc u es o L-LA and D-LA a e depic ed in Scheme 2.8. Iso ac ic poly(L-lac ic acid) (PLLA) is a semic ys alline polyme wi h a glass- ansi ion empe a u e nea 60 ºC and a mel ing empe a u e nea 180 ºC (Tang e al., 2004). Scheme 2.8. Chemical s uc u e o L- and D-lac ic acid. Lac ic acid can be p oduced ia ei he chemical syn hesis o mic obial e men a ion. Howe e , he chemical p ocesses p oduce a acemic (50:50) mix u e o D- LA and L-LA (D,L-LA). Glucose is ans o med o py u ic acid h ough he glycolysis pa hway. Many bac e ia con ain an enzyme called lac a e deshyd ogenase (LDH) which con e s py u ic acid o lac ic acid. Depending on he bac e ial species and i s LDH speci ici y, he lac ic acid e men a ion p ocess can p oduce e y pu e D-LA o L-LA o a mix u e o hem. Molecula biology ools ha e been employed o dele e he D-LDH genes o enhance he op ical pu i y o i s L-LA syn hesis (Jem e al., 2010). Unde high empe a u e (> 100 ºC), D-LA o L-LA may be con e ed o each o he h ough a acemiza ion p ocess, which e en ually esul s in a acemic mix u e wi h in e io op ical Chap e 2 30 p ope ies (Benninga, 1990). The e o e, p ocessing a ele a ed empe a u e should be a oided. Polyme iza ion o lac ic acid can be conduc ed ei he by di ec polycondensa ion o LA, o by a ing-opening polyme iza ion o he lac ide, a cyclic dime o LA. The di ec polycondensa ion p ocess dehyd a es LA o o m oligome s which a e u he polyme ized o PLA unde simul aneous dehyd a ion o a oid he deg ada ion o polyme in he p esence o mois u e. Remo al o wa e gene a ed by he LA condensa ion is usually e y di icul du ing he inal s age o polyme iza ion as he di usion o mois u e in a highly iscous polyme ic mel is e y slow. The esidual wa e apped will educe PLA molecula weigh s. The di ec polyme iza ion p ocess is epo ed o be used only by Tonji and Mi sui Chemicals companies (Chen and Pa el, 2012). Mos indus ial PLA p oduc ion p ocesses employ he con e sion o lac ides o PLA ia a ing-opening polyme iza ion (ROP) ca alyzed by o ganome allic ca alys s (Du e al., 2007 and Pang e al., 2008). Du ing he p ocess, LA is dehyd a ed and condensed in o i s oligome s a high empe a u e unde acuum o emo e mois u e. Subsequen ly lac ide is ob ained om ca aly ic depolyme iza ion o hese sho polylac ic acid chains unde educed p essu e. Residual LA is emo ed om lac ide ia dis illa ion o c ys alliza ion. The pu i ied lac ide is polyme ized in o PLA a empe a u es abo e he mel ing poin o lac ide and below he deg ada ion empe a u es o PLA. 2.4.1.2. Polyhyd oxyalkanoa es (PHAs) Whe eas PLA p oduc ion is a wo-s age p ocess ( e men a ion o monome ollowed by a con en ional polyme iza ion s ep), polyhyd oxyalkanoa es (PHAs) a e he only bioplas ics comple ely syn hesized by mic oo ganisms. PHA can be syn hesized by o e 30% o soil inhabi ing bac e ia (Chen and Pa el, 2012). Scheme 2.9. Chemical s uc u e o polyhyd oxyalkanoa es. Polyes e s: T adi ional p oduc s and p esen bio-based endencies 31 The gene ic chemical s uc u e o PHAs is depic ed in Scheme 2.9, whe e x is 1 o all comme cially ele an polyme s and R can be ei he hyd ogen o hyd oca bon chains. Poly(3-hyd oxybu y a e) (PHB), wi h R=me hyl, poly(3-hyd oxy ale a e) (PHV), wi h R=e hyl, and poly(3-hyd oxyhexanoa e) (PHH), wi h R=p opyl, a e some o he mos widely known PHAs. The bac e ia can be ed a ange o di e en ca bon sou ces; o ins ance, E. coli ed wi h a ange o oils p oduces di e en composi ions o poly(HB-co- HH), whe eas R. eu opha ed wi h a combina ion o glucose and p opiona e p oduces poly(HB-co-HV). Homopolyme s, andom copolyme s and block copolyme s o PHAs can be p oduced depending on he bac e ial species and g ow h condi ions (Gao, 2011). PHAs wi h Tg anging om -50 o 4 ºC, and Tm be ween 60 and 170 ºC ha e been de eloped. Such di e si y has allowed he de elopmen o a ange o applica ions including en i onmen ally iendly biodeg adable plas ics o packaging pu poses, ibe s, biodeg adable and biocompa ible implan s and con olled d ug elease ca ie s (Wu e al., 2000). 2.4.2. Al e na i e ou es om enewable sou ces o con en ional monome s In his sec ion, al e na i e ou es om enewable sou ces o p oduce monome s which a e cu en ly ob ained om pe ochemical eeds ock a e desc ibed. The use o hese bio-based monome s does no en ail di e ences in e ms o ma e ial p ope ies be ween pa ially bio-based polyes e s and hei pe ochemical coun e pa s, since hey ha e exac ly he same chemical s uc u e. Succinic acid. Bio-based succinic acid may be p oduced by anae obic e men a ion using a ious ypes o mic oo ganisms. Fo example, succinic acid can be p oduced om glucose by he umen o ganism Ac inobacillus succinogenes; and can also be p oduced by Ana obiospi illum succinip oducens using glucose o e en lac ose, suc ose, mal ose o uc ose as ca bon sou ces (Ryu e al., 1999; Lee e al., 2003). Feeds ocks including co n s a ch, co n s eep liquo , whey, cane molasses, glyce ol, lignocelluloses, ce eals, and s aw hyd olases could be u ilized o succinic acid p oduc ion (Xu and Guo, 2010). The F ench s a ch and s a ch de i a i e p oduce Roque e and he Du ch chemical company DSM ha e buil a demons a ion plan in F ance o p oduc ion o se e al hund ed ons o succinic acid pe yea om s a ch using e men a ion echnology. Also BASF and he Du ch company Pu ac a e join ly pu suing succinic acid p oduc ion. Chap e 2 32 Mi subishi Japan has also a emp ed o indus ialize succinic acid mic obial p oduc ion (Chen and Pa el, 2012). Adipic acid. The bio-based adipic acid is s ill in i s nascen s a e and i is no comme cially a ailable nowadays. Howe e , companies as Ve dezyne and Renno ia a e de eloping bio-based ou es o p oduce adipic acid. The bio-based p ocess ca ied ou by Ve dezyne uses gene ically modi ied enzymes o e men glucose o adipic acid. On he o he hand, Renno ia uses ai oxida ion o con e glucose o gluca ic acid, ollowed by hyd odeoxygena ion o con e gluca ic acid o adipic acid (IHS Chemical P ocess Economics P og am, 2012). Te eph halic acid. Te eph halic acid has been epo ed as po en ially being made om bio-based p-xylene p oduced by depolyme iza ion o lignin (Bozell e al., 2007). Recen ly, he p oduc ion o e eph halic acid om limonene has been pa en ed. In his case bio- based e eph halic acid is p oduced by he hyd ogena ion o limonene o p-cymene using zeoli es and he subsequen oxida ion o his compound (Be i e al., 2010). This echnology needs, howe e , u he de elopmen and does no o e an economically iable p oduc ion ou e o he sho o mid e m, mainly due o he di icul accessibili y o limonene. E hylene glycol. Mic obial e hanol o applica ion as bio uel is being p oduced a he mul imillion on scale, om s a ch and om suga . Bioe hanol can be ca aly ically dehyd a ed o e hylene wi h ac i a ed clay, phospho ic acid, sul u ic acid, ac i a ed alumina, me al oxides and zeoli es as ca alys s (Huang e al., 2008). Using bio-based e hylene, bio-based e hylene glycol can be p oduced ia he con en ional ou e o di ec oxida ion o e hylene oxide ollowed by he mal hyd olysis (Rebsda and Maye , 2000). The la ge be e age company Coca-Cola Co. in oduced in 2009 he Plan Bo le as he i s ecyclable PET bo le using up o 30% bio-based monome s; bio-based e hylene glycol and ecycled PET a e employed in PET p oduc ion. PepsiCo de eloped he i s 100% bio-based bo le in 2011 (PepsiCo, 2011). I has also been announced a new gene a ion o 100% bio-based Plan Bo le om Coca-Cola Co. (Coca-Cola Co., 2011). 1,3-P opanediol. The p oduc ion o bio-based 1,3-p opanediol has been de eloped and comme cialized by he join en u e DuPon Ta e & Lyle LLC, wi h an annual capaci y o 45,000 ons. Bio-based 1,3-p opanediol is p oduced ia he e men a ion o glucose. The e is a e men a ion pa hway in na u e which consis s o wo s eps: na u ally occu ing yeas s i s e men glucose o glyce ol and hen mic obes e men glyce ol o 1,3- Polyes e s: T adi ional p oduc s and p esen bio-based endencies 33 p opanediol. In he pa en ed indus ial biop ocess, glucose de i ed om we -milled co n is me abolized by gene ically enginee ed mic oo ganism E. coli; his mic oo ganism con e s glucose o 1,3-p opanediol in a single s ep (DuPon , 2013). 1,4-Bu anediol. Genoma ica Inc. de eloped a suc ose-based p ocess o he manu ac u e o 1,4-bu anediol by an enginee ed mic oo ganism (Chen and Pa el, 2012). On he o he hand, 1,4-bu anediol can also be p oduced om bio-based succinic acid in ol ing h ee s eps: co n-de i ed glucose is e men ed o succinic acid, succinic acid is hen pu i ied by elec odialysis and i is inally educed ca aly ically o 1,4-bu anediol. Recen ly, an aqueous-phase hyd ogena ion o biomass-based succinic acid o 1,4- bu anediol o e suppo ed bime allic ca alys s was epo ed (Minh e al., 2010). Howe e , mos 1,4-bu anediol is s ill p oduced om chemical p ocesses. 1,10-Decanediol. By eac ing cas o oil wi h NaOH o KOH a ele a ed empe a u es and in he p esence o ca alys s, sebacic acid and 2-oc anol a e o med p e e ably. Then sebacic acid can be con e ed o 1,10-decanediol ia hyd ogena ion. Thus, 1,10- decanediol has been epo ed as a po en ial bio-based de i a i e o he cas o oil (Mu lu and Meie , 2010). 2.4.3. Polyes e s om ca bohyd a e-de i ed monome s wi h modi ied p ope ies 2.4.3.1. Unp o ec ed aldi ols and alda ic acids Linea polycondensa ion o monome s de i ed om ca bohyd a es is no s aigh o wa d. Ca bohyd a e-based compounds usually possess an excess o unc ional g oups ha upon polycondensa ion would lead o undesi able c oss-linking eac ions unless special p ecau ions a e aken. Ne e heless, some linea polycondensa es ha e been syn hesized using suga -de i ed monome s bea ing ee hyd oxyl g oups by a solu ion polycondensa ion app oach (Kiely e al., 1994 and 2000). Lipases ha e been epo ed o p o ide egioselec i i y du ing es e i ica ion eac ions o aldi ols a mild empe a u es. In 2000, he i s example o an aldi ol used as monome in enzyme-ca alyzed polyme iza ion was desc ibed; D-gluci ol was polyme ized h ough i s posi ions C-1 and C-6 wi h di inyl sebaca e in CH3CN (Uyama e al., 2000). The p epa a ion o polyes e s om 1,8-oc anediol, adipic acid and se e al unp o ec ed aldi ols, such as e y h i ol, xyli ol, ibi ol, D-manni ol, D-gluci ol and galac i ol, has also Chap e 2 34 been epo ed. Polyme iza ions we e ca ied ou unde acuum, using he immobilized Lipase B om Candida an a c ica (No ozyme 435) as ca alys (Hu e al., 2006). 2.4.3.2. Acyclic O-p o ec ed aldi ols and alda ic acids Al hough some syn heses leading o linea polyes e s ha e been ealized using suga -de i ed monome s wi h ee hyd oxyl g oups (see abo e), mos o hem a e ca ied ou wi h de i a i es in which he seconda y hyd oxyl g oups ha e been app op ia ely blocked (Scheme 2.10). Scheme 2.10. Modi ica ion o ca bohyd a es leading o O-p o ec ed aldi ols and alda ic acids. The pionee ing wo k o D ew and Hawo h in he 1920s desc ibed he polycondensa ion o 2,3,4- i-O-me hyl-L-a abinonic acid o gi e an oligome ic ma e ial no comple ely cha ac e ized (D ew and Hawo h, 1927). Also in he ield o alipha ic polyes e s om acyclic O-p o ec ed ca bohyd a e-based monome s, se e al poly(alkylene dica boxyla es) ha e been ecen ly ob ained by polycondensa ion eac ion o he aldi ols 2,3,4- i-O-me hyl-L-a abini ol and 2,3,4- i-O-me hyl-xyli ol, and alda ic acids 2,3,4- i-O-me hyl-L-a abina ic acid and 2,3,4- i-O-me hyl-xyla ic acid (Ga cía- Ma ín e al., 2006). The chemical s uc u es o hese O-p o ec ed ca bohyd a e-based monome s a e depic ed in Scheme 2.11. 1,4-Bu anediol and adipic acid we e also used as comonome s. Polyes e s: T adi ional p oduc s and p esen bio-based endencies 35 Scheme 2.11. Chemical s uc u e o some monome s de i ed om L-a abinose and D-xylose. The syn hesis o a oma ic polyes e s, speci ically o poly(ph hala e)s, using ca bohyd a e-based acyclic O-p o ec ed monome s has also been explo ed. Thus poly(e hylene e eph hala e) (PET), poly(e hylene isoph hala e) (PEI) and poly(bu ylene e eph hala e) (PBT) ha e been chemically modi ied by inse ion o di e en O-me hyl aldi ols (Galbis and Ga cía-Ma ín, 2008 and 2010). Fi s ly, a se ies o PET copolyes e s con aining 2,3-di-O-me hyl-L- h ei ol we e p epa ed and duly cha ac e ized (Kin e al., 2001). La e PET and PEI analogues wi h o al eplacemen o he e hylene glycol uni s by 2,3,4,5- e a-O-me hyl-hexi ols ha ing ei he D-manno o galac o con igu a ions we e syn hesized (Zamo a e al., 2005a). Polyes e s analogous o PET, PEI and PBT ha e also been p epa ed by using 2,3,4- i-O-me hyl-L-a abini ol and 2,3,4- i-O-me hyl-xyli ol (Zamo a e al., 2005b; Alla e al., 2006). The 2,3,4- i-O-benzyl e he s o L-a abini ol and xyli ol we e also used o syn hesize polyes e s analogous o PET and PBT (Zamo a e al., 2008). Bu ylene copolyes e s based on O-me hyl alda ic acids as L-a abina ic and galac a ic acids, and e eph halic acid we e also p epa ed and cha ac e ized (Zamo a e al., 2009). The chemical s uc u es o some o hese O-p o ec ed ca bohyd a e-based monome s a e depic ed in Scheme 2.12. Scheme 2.12. Chemical s uc u e o some monome s de i ed om D-galac ose and D-mannose. Chap e 2 36 The hyd oly ic deg ada ion o a se ies o homo- and copolyes e s analogous o PET and PEI based on O-me hyl p o ec ed L-a abini ol, xyli ol, D-manni ol and galac i ol was ela i ely as a empe a u es 10 ºC abo e hei espec i e Tg. The hyd olysis o copolyes e s ook place p e e en ially by clea age o he es e g oups o he suga uni s (Zamo a e al., 2006). The hyd oly ic deg ada ion o PBT copolyes e s con aining up o 50% o O-me hyl p o ec ed pen i ols de i ed om L-a abinose and D-xylose was also s udied (Alla e al., 2006). I was shown ha hese copolyes e s we e much mo e sensi i e o hyd olysis han was PBT. 2.4.3.3. 2,5-Fu andica boxylic acid (FDCA) The esea ch s a egy ela ed o u an polyme s elies on he use o wo u an de i a i es, i.e. u u al (F) and hyd oxyme hyl u aldehyde (HMF), as s a ing building blocks om which wo se s o monome s can be syn hesized: hose con aining double bonds sui able o chain polyme iza ions and copolyme iza ions, and hose wi h ca boxyl o hyd oxyl unc ionali ies associa ed wi h s ep-g ow h mechanisms (Gandini and Belgacem, 1997; Gandini, 2010 and 2011). Fu u al (F) is p oduced as an indus ial commodi y, wi h a yea ly p oduc ion close o 300,000 ons. I s p ecu so s a e pen oses p esen in co n, ice, suga and co on, among o he s. Fu u al p oduc ion is based on he acid ca alyzed hyd oly ic depolyme iza ion o C5 hemicelluloses, pa icula y xylanes. Mos o he u u al is oday con e ed in o u u yl alcohol (FA), which is ex ensi ely employed as a p ecu so o a a ie y o esins o se e al applica ions. The second u an de i a i e which can be p epa ed om he app op ia e C6 polysaccha ides is hyd oxyme hyl u aldehyde (HMF). The chemical s uc u es o hese u an-based p oduc s a e depic ed in Scheme 2.13. The acid-ca alyzed dehyd a ion o uc ose o HMF can be pe omed in high-boiling pola sol en s, in supe c i ical ace one and wa e , o by addi ion o phase modi ie s (Mo eau e al., 2004; Román-Leshko e al., 2006; Zhao e al., 2007). Polyes e s: T adi ional p oduc s and p esen bio-based endencies 37 Scheme 2.13. Chemical s uc u e o u u al (F), u u yl alcohol (FA), hyd oxyme hyl u aldehyde (HMF) and 2,5- u andica boxylic acid (FDCA). Especially 2,5- u andica boxylic acid (FDCA), as a HMF de i a i e, has gained pa icula a en ion as a sui able monome o s ep-g ow h polyme iza ion. Moo e and Kelly ini ially explo ed he scope and limi a ions o FDCA in polycondensa ion eac ions and syn hesized a se ies o polyes e s based on FDCA and se e al diols (Moo e and Kelly, 1978 and 1979). Howe e , due o he limi ed a ailabili y o high-pu i y FDCA, he esea ch in e es in his ield declined in he ollowing yea s. Recen de elopmen s in he ca aly ic ou es owa d high-pu i y FDCA allowed he p epa a ion o la ge amoun s o his compound, and led o a signi ican inc ease in he amoun o esea ch ca ied ou owa ds FDCA polycondensa es. The use o his compound o ob ain bio-based polyes e s has been ex ensi ely s udied in he las yea s (Gandini e al., 2009a and 2009b; Jiang e al., 2011; Wu e al., 2012a; Gubbels e al., 2013b). The gene al chemical s uc u e o he u an-based polyes e s ob ained upon polycondensa ion o FDCA wi h linea alipha ic diols is depic ed in Scheme 2.14, and he he mal p ope ies o his amily o compounds a e shown in Table 2.1. Scheme 2.14. Chemical s uc u e o u an-based polyes e s ob ained upon polycondensa ion o FDCA wi h linea alipha ic diols. FDCA was used in conjunc ion wi h e hylene glycol o syn hesize poly(e hylene 2,5- u andica boxyla e) (PEF), i.e. he u an analog o PET. The eplacemen o he e eph hala e ing by he u an coun e pa led o a dec ease in mel ing empe a u e compa ed o PET, whe eas main ained i s glass- ansi ion empe a u e (Gomes e al., Chap e 2 44 S o beck and Ballau pe o med polycondensa ion o e eph haloyl chlo ide wi h isoso bide and e hylene glycol. In insic iscosi ies o up o 0.46 dL·g-1 we e ob ained. They s udied he en i e ange o diol p opo ions, and ound ha isoso bide-based PET copolyes e s we e amo phous abo e 20 mol% o isoso bide (S o beck and Ballau , 1996). The classical indus ial mel polycondensa ion om e eph halic acid o dime hyl e ep hala e we e co e ed by pa en (Cha bonneau e al., 1999). The con en o isoso bide in he eed was no o ally inco po a ed in o he polyes e chains; signi ican amoun s o isoso bide we e los by dis illa ion du ing he es e i ica ion o du ing he anses e i ica ion s ep. Fenouillo e al. pe o med also s udies on mel polycondensa ion o such copolyes e s o quan i y he ac ual p opo ion o isoso bide inse ed in o he polyes e chains, and ound ha abou 25% o isoso bide was los (Fenouillo e al., 2010). K icheldo e al. s udied polycondensa ion o 1,4-bu anediol wi h isoso bide and ei he dime hyl e ep hala e in bulk using TBT as ca alys , o e eph haloyl chlo ide in solu ion using py idine as ca alys and HCl accep o (K icheldo e al., 2007). Copolyes e s wi h e y low molecula weigh s, i.e. inhe en iscosi ies be ween 0.08 and 0.37 dL·g-1, we e ob ained by anses e i ica ion in he mel . Howe e highe inhe en iscosi ies, wi h alues o up o 0.74 dL·g-1, could be a ained by using polycondensa ion in solu ion wi h e ep haloyl chlo ide. Isoso bide-based PBT copolyes e s we e ound o be amo phous o isoso bide con en s abo e 32 mol%. The indus ial applica ions o copolyes e s con aining low o mode a e p opo ions o isoso bide a e ha o classical o PET o PBT aking ad an age o he inc eased glass- ansi ion empe a u e. Nume ous pa en s desc ibed isoso bide-based PET and PBT copolyes e s; some o hem claimed he me hod o polyme iza ion while se e al claimed speci ic polyes e applica ions. Fo ins ance, he addi ion o isoso bide in o PET o p oduce bo les able o esis ho - ill p ocess (Cha bonneau and Johnson, 1999) and he mo o mable shee s whe e a low a e o c ys alliza ion is equi ed (Khana ian e al., 2000) ha e been pa en ed. Also ibe s, ilms and polyme blends we e ci ed (Khana ian e al., 2002). Fu he mo e, he inco po a ion o isoso bide by anses e i ying poly(e hylene e eph hala e) wi h poly(isoso bide e eph hala e) oligome s in bulk a 285 ºC was also pa en ed (Adelman e al., 2003). In his way hey could inco po a e 24 mol% o isoso bide ela i e o he o al diol con en , and he polyme ob ained was amo phous wi h Tg= 139 ºC and an inhe en iscosi y o 0.57 dL·g-1. In his case he aim was no o compe e wi h PET bu a he wi h polyca bona e (PC) o Polyes e s: T adi ional p oduc s and p esen bio-based endencies 45 poly(me hyl me hac yla e) (PMMA). A his poin i should be s a ed ha all a oma ic copolyes e s con aining isoso bide a e yellowish, an impo an law o ce ain applica ions. The sensi i i y o isoso bide o he mooxida ion a he high empe a u es needed o polyme ize polyes e s is he cause o yellowing. The e o s o sol ing his p oblem we e highligh ed in a ecen pa en om Cha bonneau on poly(e hylene-co- isoso bide e ep hala e); he syn he ic ou es ci ed we e he ypical PTA o DMT syn hesis bu wi h he obse a ion ha oxygen should absolu ely be a oided in he eac i e medium. Mo eo e , wo an ioxidan s we e added jus be o e polycondensa ion: he p ima y one was a hinde ed phenol and he seconda y one was a i alen phospho ous compound (Cha bonneau, 2006). Recen ly, Sablong e al. s udied he inco po a ion o isoso bide in o PBT by solid-s a e modi ica ion (SSM). Expe imen s using SSM o he di ec inco po a ion o isoso bide in o PBT we e unsuccess ul; isoso bide could no be inco po a ed unde such condi ions, due o he ela i ely low eac i i y o i s wo seconda y hyd oxyl. The syn hesis o a mac odiol bea ing wo p ima y hyd oxyl g oups, om isoso bide, e ep haloyl chlo ide and 1,4-bu anediol was necessa y o inco po a e isoso bide in o he PBT chain. Ve y high molecula weigh s (Mn= 80,000-140,000 g·mol-1) could be a ained by using his echnique (Sablong e al., 2008). Isoso bide and isoidide ha e also been polyme ized wi h he dichlo ide de i a i e o 2,5- u andica boxylic acid in solu ion. Amo phous polyes e s wi h high glass- ansi ion empe a u es, i.e. 180 ºC o poly(isoso bide 2,5- u andica boxyla e) (Mn= 13,700 g·mol-1) and 140 ºC o poly(isoidide 2,5- u andica boxyla e) (Mn= 5,700 g·mol-1), we e ob ained (Gomes e al., 2011). The low eac i i y o he seconda y hyd oxyl g oups o he 1,4:3,6- dianhyd ohexi ols explains why he syn hesis o mo e eac i e de i a i es such as amines (Thiem and Lüde s, 1986; Bachmann e al., 1998; Jasinska e al., 2011) o isocyana es (P e e e al., 2011a and 2011b), has been conside ed. Rega ding polyes e syn hesis om isohexide-de i ed monome s wi h enhanced eac i i y, ano he s a egy is based on chain ex ension a C2 and C5 o he isohexide skele on. Ve y ecen ly he syn hesis o a 1-ca bon ex ended isohexide de i a i e wi h dica boxylic unc ionali y, namely isoidide dica boxylic acid (IIDCA), and a 1-ca bon ex ended diol wi h p ima y hyd oxyl g oups, namely isoidide hyd oxyme hylene diol (IIDML), has been epo ed (Wu e al., 2011). Thei chemical s uc u es a e depic ed in Scheme 2.19. Chap e 2 46 Scheme 2.19. Chemical s uc u e o he 1-ca bon ex ended isohexide de i a i es IIDCA and IIDML. The main p ope ies o polyes e s based on hese 1-ca bon ex ended isohexide de i a i es a e p esen ed in Table 2.3. Alipha ic polyes e s wi h Mw in he 13,000-34,000 g·mol-1 ange we e ob ained by mel polycondensa ion om he dime hyl es e o IIDCA and alipha ic diols wi h 2 o 12 me hylene g oups (Wu e al., 2012b). These alipha ic polyes e s we e semic ys alline, wi h Tm alues in he 40-125 ºC ange. The glass- ansi ion empe a u es we e be ween -33 ºC and 18 ºC. The syn hesis o a se ies o ully isohexide-based polyes e s has been ecen ly epo ed (Wu e al., 2013). The combina ion o he dime hyl es e o he IIDCA wi h isoso bide, isomannide o isoidide esul ed in semic ys alline low molecula weigh polyes e s (Mw= 1,700-3,600 g·mol-1) wi h Tm in he 80-170 ºC ange. Tg alues we e 73, 30 and 85 ºC o polyes e s ob ained om he dime hyl es e o IIDCA and isoso bide, isomannide o isoidide, espec i ely. Also a ully isohexide-based polyes e om he dime hyl es e o IIDCA and he ex ended diol IIDML was p epa ed using he same mel polycondensa ion condi ions. An inc ease in he eac i i y o he ex ended diol bea ing wo p ima y hyd oxyl g oups wi h espec o he seconda y hyd oxyl g oups o isoidide was epo ed; he Mw o his IIDCA-IIDML polyes e being 10,400 g·mol-1. This polyes e was semic ys alline and i s glass- ansi ion empe a u e was 48 ºC (Wu e al., 2013). Howe e he 1-ca bon ex ension esul ed in a signi ican dec ease in Tg o he esul ing polyes e s compa ed o inco po a ion o he pa en isohexide; he IIDCA-isoidide polyes e showed a Tg alue o 85 ºC depi e ha ing lowe molecula weigh . When compa ed o he polyes e om e eph halic acid and isoidide, he analogous polyes e con aining he ex ended isodide diol IIDML also showed a d ama ic d op in Tg o app ox. 100 ºC (209 ºC s. 105 ºC) (Wu, 2012; an Es, 2013). Polyes e s: T adi ional p oduc s and p esen bio-based endencies 47 Table 2.3. The mal p ope ies and molecula weigh s o polyes e s om monome s based on chain ex ension a C2 and C5 o he isohexide skele on. The mal p ope ies Molecula weigh s Diol Diacid Tg (ºC) Tm (ºC) Mn (g·mol-1) Mw (g·mol-1) Re . e hylene glycol IIDCA 18 125 6,100 13,100 Wu e al., 2012b 1,4-bu anediol IIDCA 0 47/62a 14,100 34,100 Wu e al., 2012b 1,6-hexanediol IIDCA -20 54 10,200 22,800 Wu e al., 2012b 1,8-oc anediol IIDCA -30 43/51/55a 10,000 17,100 Wu e al., 2012b 1,10-decanediol IIDCA -33 43/54a 11,800 24,600 Wu e al., 2012b 1,12- dodecanediol IIDCA -30 57/64a 8,800 18,000 Wu e al., 2012b isoso bide IIDCA 73 125/168a 2,600 3,300 Wu e al., 2013 isomannide IIDCA 30 89 1,200 1,700 Wu e al., 2013 isoidide IIDCA 85 109/143a 2,500 3,600 Wu e al., 2013 IIDML IIDCA 48 118/150a 5,400 10,400 Wu e al., 2013 IIDML e eph halic 105 268/277/ 296a 7,700 17,700 Wu, 2012 a Mul iple mel ing peak. 2.4.3.5. Cyclic ace alized aldi ols, aldonic and alda ic acids The use o cyclic ace alized aldi ols, aldonic and alda ic acid de i a i es as building blocks o he syn hesis o polycondensa es is no new, bu e y ew cases ha e been epo ed so a :  The syn hesis and c ys al s uc u e o linea polyamides om 2,3-di-O-me hylene-L- a a ic acid and se e al diamines ha e been desc ibed (Rod íguez-Galán e al., 1992; I iba en e al., 2000), and hei biodeg adabili y has been es ed (Kimu a e Chap e 2 48 al., 1999). The inco po a ion o he dime hyl es e de i a i e in o polyes e s has been ecen ly epo ed (Japu e al., 2013a).  Low molecula weigh polyes e s made om 2,3-di-O-isop opylidene-L- a a ic acid and linea alkanediols and om 2,3-di-O-isop opylidene-L- h ei ol and alipha ic diacids ha e been epo ed (Dhamaniya and Jacob, 2010 and 2012).  Polyu e hanes ha e been syn hesized om 2,3-di-O-isop opylidene-L- h ei ol and om 2,3-di-O-me hylene-L- h ei ol (Ma ín and Muñoz-Gue a, 2008).  In he 1950s, Mehl e e and Mellies epo ed on he polyme iza ion o 2,4:3,5-di-O- me hylene-D-gluconic acid in an a emp o benzoyla e his compound wi h an equi alen amoun o benzoyl chlo ide o benzoic anhyd ide in py idine solu ion (Mehl e e and Mellies, 1955).  Polyu e hanes om 1-amino-1-deoxy-2,3:4,5-di-O-isop opylidene-D-galac i ol ha e been p epa ed (Gómez and Va ela, 2009).  2,4:3,5-di-O-me hylene-D-gluci ol has been used as monome o he p epa a ion o polyu e hanes (Ma ín and Muñoz-Gue a, 2009), and i s inco po a ion in o polyes e s is cu en ly being s udied in ano he PhD hesis in ou esea ch g oup (Japu e al., 2012 and 2013b). The chemical s uc u e o hese cyclic ace alized aldi ols, aldonic and alda ic acids a e depic ed in Scheme 2.20. Scheme 2.20. Chemical s uc u e o cyclic ace alized aldi ols, aldonic and alda ic acids being s udied so a . 2,3-di-O-me hylene-L- h ei ol 2,3-di-O-me hylene-L- a a ic acid 2,3-di-O-isop opylidene-L- a a ic acid 2,3-di-O-isop opylidene-L- h ei ol HO O O O O OH 2,4:3,5-di-O-me hylene-D-gluci ol HO O O O O NH2 1-amino-1-deoxy- 2,3:4,5-di-O-isop opylidene-D-galac i ol HO O OH O HO O OH O O O HO O OH O HO O OH O O O HO O O O O OH 2,4:3,5-di-O-me hylene-D-gluconic acid O Polyes e s: T adi ional p oduc s and p esen bio-based endencies 49 2.5. Re e ences Adelman, D.J.; Cha bonneau, L.F.; Ung, S. US Pa en 6656577 ( o E.I. du Pon de Nemou s and Co.), 2003. Albe sson, A.-C.; Va ma, I.K. Biomac omolecules 2003, 4, 1466-1486. Alla, A.; Hakkou, K.; Zamo a, F.; Ma ínez de Ila duya, A.; Galbis, J.A.; Muñoz-Gue a, S. Mac omolecules 2006, 39, 1410-1416. Al un, S.; Ulcay, Y. J. Polym. 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Jem, K.J.; an de Pol, J.F.; de Vos, S. Plas ics om Bac e ia, Na u al Func ions and Applica ions; Sp inge : Heidelbe g, 2010, pp. 323-346. Jiang, M.; Liu, Q.; Zhang, Q.; Ye, C.; Zhou, G. J. Polym. Sci., Polym. Chem. 2011, 50, 1026-1036. Kampou is, E.; Papaspy ides, C. Polyme 1985, 26, 413-417. Khana ian, G.; Cha bonneau, L.F.; Johnson, R.E.; Wi ele , H.B.; Lee, R.G.; Sando , R.B. US Pa en 6025061 ( o HNA Holdings, Inc.), 2000. Khana ian, G.; Cha bonneau, L.F.; Wi ele , H.B. US Pa en 6359070 ( o E.I. Du Pon de Nemou s and Co.), 2002. Ki, H.C.; Pa k, O.O. Polyme 2001, 42, 1849-1861. Kiely, D.E.; Chen, L.; Lin, T.-H. J. Am. Chem. Soc. 1994, 116, 571-578. Kiely, D.E.; Chen, L.; Lin, T.-H. J. Polym. Sci., Polym. Chem. 2000, 38, 594-603. Kim, Y.J.; Pa k, O.O. J. Appl. Polym. Sci. 1999, 72, 945-951. Kimu a, H.; Yoshina i, T.; Takeishi, M. Polym. J. 1999, 31, 388-392. Chap e 3 60 Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 61 3.1. Aim and scope o his Chap e D i en by inc easing conce ns on sus ainable de elopmen and minimizing he impac o ma e ials on he en i onmen , biodeg adable polyme s ha e a ac ed a g ea deal o in e es in he las decades. Among syn he ic biodeg adable polyme s, alipha ic polyes e s a e he mos widely s udied and la gely used. Alipha ic polyes e s such as poly(bu ylene succina e) (PBS), poly(L-lac ic acid) (PLA), poly(ε-cap olac one) (PCL) and poly(3-hyd oxy bu y a e) (PHB) ha e ound in ensi e use in a b oad a ie y o medical applica ions such as bio eso bable su gical su u es, p os hesis, den al implan s, bone sc ew and pla es o empo a y in e nal ac u e ixa ion, and con olled d ug deli e y sys ems. Alipha ic polyes e s a e also ecei ing a en ion as ma e ials sui able o eplacing con en ional commodi y plas ics in injec ion-molded a icles (cu le y, b ushes), ubula ilms (compos ing bags, shopping bags), packaging and ood ay. Howe e , mos o hem ha e a glass- ansi ion empe a u e (Tg) no high enough o i s use in hose applica ions whe e s i ness and he mal esis ance a e p io i y equisi es. In his ega d, a ious app oaches such as blending and copolyme iza ion wi h a oma ic polyes e s as poly(bu ylene e eph hala e) (PBT) and poly(e hylene e eph hala e) (PET) ha e been explo ed. The in e es o cyclic monome s a ises om hei capaci y o adding s i ness o he polyme chain wi h he subsequen inc ease in Tg; he disad an age o using a oma ic uni s o such pu pose is ha hey a e o igina ed om ossil eeds ocks and a e eluc an o biodeg ada ion. The use o ca bohyd a e-based monome s wi h a cyclic s uc u e cons i u es a sca cely explo ed app oach o he p epa a ion o enewable alipha ic polyes e s wi h imp o ed physical p ope ies, especially hose ela ed o polyme chain s i ness. Mo eo e , ca bohyd a e-de i ed polycondensa es ypically display enhanced hyd ophylici y, lowe oxici y and highe suscep ibili y o hyd oly ic deg ada ion and biodeg ada ion han hose coming om pe ochemical eeds ocks. 1,4:3,6-Dianhyd o-D-gluci ol, known as isoso bide, along wi h hei wo less accessible s e eoisome s isomannide and isoidide, a e cu en ly d awing an eno mous in e es in he polyme science ield as bio-based monome s able o p o ide enhanced s i ness in o he polyme chain hey a e inco po a ed. Ne e heless, he main sho coming o isoso bide and i s isome s is he limi ed eac i i y o hei seconda y hyd oxyl g oups; in ac , his ea u e se iously hampe s he polycondensa ion eac ion in he mel , so alipha ic polyes e s om 1,4:3,6-dianhyd ohexi ols and alipha ic dica boxylic Chap e 3 62 acids o dica boxylic es e s ob ained by his me hod display a he limi ed molecula weigh s. Highe molecula weigh s a e achie able ia polycondensa ion wi h alipha ic dica boxylic chlo ides, bu his me hod is no app op ia e o indus ial applica ion. In his Chap e , alipha ic polyes e s om bicyclic ace alized ca bohyd a e-based monome s will be ob ained by polycondensa ion in he mel and in he o al absence o sol en s, o imi a e as a as possible he condi ions usually applied in he indus y. The cha ac e iza ion o he new polyes e s, he e alua ion o hei he mal and mechanical p ope ies and hei deg adabili y and biodeg adabili y will be epo ed. Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 63 3.2. Ca bohyd a e-based polyes e s made om bicyclic ace alized galac a ic acid Summa y: The dime hyl es e o 2,3:4,5-di-O-me hylene-galac a ic acid (Galx) was made o eac in he mel wi h 1,n-alkanediols HO(CH2)nOH con aining e en numbe s o me hylenes (n om 6 o 12) o p oduce linea polycyclic polyes e s. Two se s o poly(alkylene 2,3:4,5-di-O-me hylene-galac a a e) polyes e s (PE-nGalx) wi h weigh - a e age molecula weigh s in he  5,000-10,000 and  35,000-45,000 g·mol-1 anges we e ob ained using TBT and DBTO ca alys s, espec i ely. Fo compa a i e pu poses a se o poly(alkylene adipa e) polyes e s (PE-nAd) was also syn hesized wi h molecula weigh s in he highe ange using a simila p ocedu e. The he mal s abili y o PE-nGalx was g ea e han ha o PE-nAd al hough i no ably decayed as molecula weigh dec eased. The eplacemen o Ad by Galx in he polyes e s caused inc eases in Tg o up o 70 ºC, and almos doubled he ensile mechanical pa ame e s. All PE-nGalx we e semic ys alline bu only hose made om 1,12-dodecanediol we e able o c ys allize om he mel wi h a c ys alliza ion a e ha diminished as he molecula weigh inc eased. In gene al, he galac a a e con aining polyes e s displayed highe solubili y and we abili y han polyadipa es, hey hyd olyzed as e and exhibi ed compa able sensi i i y o he ac ion o lipases. Publica ion de i ed om his wo k: La illa, C.; Alla, A.; Ma ínez de Ila duya, A.; Beni o, E.; Ga cía-Ma ín, M.G.; Galbis, J.A.; Muñoz-Gue a, S. Biomac omolecules 2011, 12, 2642-2652. Chap e 3 64 3.2.1. In oduc ion The de elopmen o bio-based polyme s oday is d awing an eno mous amoun o in e es o hei po en ial o educe he u iliza ion o pe ochemicals and o inc ease he added- alue o ag icul u e p oduc s and was es (Wool and Sun, 2005). Among he enewable na u ally-occu ing sou ces, ca bohyd a es s and ou in a p i ileged posi ion due o hei huge abundance and because hey a e inexhaus ible and eadily a ailable. A good asso men o monome s based on ca bohyd a es has been ecen ly explo ed o making di e en classes o polyme s (Wang e al., 2002; Bou e al., 1996; K icheldo , 1997; Galbis and Ga cía-Ma ín, 2008). The hyd oxyl and ca boxylic ich unc ionali y o hese compounds makes hem mos ly app op ia e o polycondensa ion in spi e o he ac ha ce ain chemical handling o g oup p o ec ion will be equi ed i linea polyme s a e sea ched. Ca bohyd a e-based polycondensa es may be p o ided wi h a g ea di e si y o chemical s uc u es and unusual p ope ies; hey ypically display enhanced hyd ophilici y, less oxici y, and highe suscep ibili y o biodeg ada ion han pe ochemical-based polycondensa es, o e ing he e o e a wide possibili y o applica ions in ood packaging and medical de ices (Ga cía-Ma ín e al., 2005; Haide and Williams, 2008). Among he wide di e si y o suga -de i ed monome s ha ha e been ecen ly explo ed, 1,4:3,6-dianhyd ohexi ols ha e d awn pa icula a en ion o he syn hesis o linea polycondensa es (Fenouillo e al., 2010; Galbis and Ga cía-Ma ín, 2010). In hese hexi ols, he ou exceeding hyd oxyl g oups a e blocked by in amolecula e he i ica ion leading o a bicyclic s uc u e wi h he seconda y 2- and 5-hyd oxyl g oups s anding ee o eac ion. The in e es o monome s ha ing a cyclic s uc u e a ises om hei capaci y o adding s i ness o he polyme chain wi h he subsequen inc easing in he Tg. 1,4:3,6- Dianhyd o-D-gluci ol known as isoso bide (Is) is he only dianhyd ohexi ol indus ially a ailable oday because i can be p oduced om ce eal s a ch h ough an economically accep able p ocess. I is composed o wo cis- used nea ly plana e ahyd o u an ings wi h a dihed al angle o 120º and he 2- and 5-hyd oxyl g oups in endo and exo posi ions, espec i ely (Scheme 3.1). Isoso bide has been ex ensi ely in es iga ed in he las decades as a con enien building block o di e se polycondensa es (Cha i e al., 2006; Caou ha e al., 2007; Sablong e al., 2008; Noo do e e al., 2008; Ma ín and Muñoz- Gue a, 2009). In his line, special a en ion is gi en o a oma ic polyes e s and copolyes e s (Thiem and Lüde s, 1984; S o beck e al., 1993, Quin ana e al., 2011), in Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 65 which Is has p o en o eplace success ully pe ochemical diols wi hou de imen , o e en wi h imp o emen , o hei p ope ies. Scheme 3.1. Chemical s uc u es o 1,4:3,6-dianhyd oso bi ol (isoso bide, Is) and dime hyl 2,3:4,5- di-O-me hylene galac a a e (Galx). In his wo k we p esen a new bicyclic ca bohyd a e-based monome use ul o he p epa a ion o linea polycondensa es, speci ically o he syn hesis o alipha ic polyes e s. Dime hyl 2,3:4,5-di-O-me hylene-galac a a e (Scheme 3.1), abb e ia ed as Galx, is he dime hyl es e o galac a ic acid wi h he hyd oxyl g oups ace alized wi h o maldehyde. This compound is eadily syn hesized in one s ep om comme cially a ailable mucic acid (galac a ic acid) which in u n is p oduced om na u ally-occu ing D- galac ose o D-galac ose-con aining compounds by oxida ion wi h ni ic acid (Bu le e al., 1958). Con a y o isoso bide, Galx is cen osymme ic and he e o e does no gene a e egici y in he g owing polyme chain, and i s wo ca boxyl g oups display he same eac i i y because hey a e spa ially undis inguishable. The use o ace alized alda ic acid de i a i es as building blocks o he syn hesis o polycondensa es is no new, bu mos o he cases epo ed so a e e o polyamides and polyes e s de i ed om ace alized a a ic acid, which con ain a dioxolane ing o ming pa o he polyme backbone. Thus, Muñoz-Gue a e al. ha e desc ibed he syn hesis and c ys al s uc u e o linea polyamides om di-O-me hylene L- a a ic acid and se e al diamines (Rod íguez-Galán e al., 1992; I iba en e al., 2000), and Kimu a e al. s udied hei biodeg adabili y (Kimu a e al., 1999). Mo e ecen ly, low molecula weigh polyes e s made om di-O-isop opylidene L- a a ic acid and alkanediols ha e been epo ed (Dhamaniya and Jacob, 2010). To ou knowledge, bicyclic ace alized alda ic acid de i a i es ha e no been explo ed o he syn hesis o polycondensa es o da e. I should be men ioned howe e ha 1-deoxy-1-isocyana e-2,3:4,5-di-O- isop opylidene-D-galac i ol has been syn hesized and used as monome o he p epa a ion o [n]-polyu e hanes (Gómez and Va ela, 2009). Chap e 3 66 3.2.2. Expe imen al sec ion 3.2.2.1. Ma e ials Dime hyl 2,3:4,5-di-O-me hylene-galac a a e was syn hesized ollowing he p ocedu e epo ed by S acey e al. (Bu le e al., 1958). The eagen s 1,6-hexanediol (97%), 1,8-oc anediol (98%), 1,10-decanediol (98%), 1,12-dodecanediol (99%), dime hyl adipa e (> 99%), and he ca alys s i anium (IV) e abu oxide (TBT, 98%) and dibu yl in oxide (DBTO, 98%) we e pu chased om Sigma-Ald ich. Sol en s used o pu i ica ion and cha ac e iza ion, as chlo o o m, me hanol and die hyl e he , and sol en s used in he solubili y essays, we e pu chased om Pan eac and we e all o ei he echnical o high- pu i y g ade. The enzymes used in biodeg ada ion expe imen s, lipase om po cine panc eas (ac i i y 15-35 U·mg-1, pH 8.0, 37 ºC) and Amano lipase om Pseudomonas luo escens (ac i i y ≥ 20 U·mg-1, pH 8.0, 55 ºC) we e also pu chased om Sigma- Ald ich. One uni (U) was de ined as ha amoun o enzyme which ca alyzed he elease o a y acid om iglyce ides a he a e o 1 µmol·min-1. All he eagen s and sol en s we e used as ecei ed wi hou u he pu i ica ion. 3.2.2.2. Gene al me hods 1H and 13C NMR spec a we e eco ded on a B uke AMX-300 spec ome e a 25.0 ºC ope a ing a 300.1 and 75.5 MHz, espec i ely. Polyes e s and wa e deg ada ion p oduc s we e dissol ed in deu e a ed chlo o o m o deu e a ed wa e , and spec a we e in e nally e e enced o e ame hylsilane (TMS) o he sodium sal o 3-( ime hylsilyl)- p opanesul onic acid. Abou 10 and 50 mg o sample dissol ed in 1 mL o sol en we e used o 1H and 13C NMR, espec i ely. A o al o 64 scans we e acqui ed o 1H and 1000-10000 o 13C, wi h 32 and 64-K da a poin s as well as elaxa ion delays o 1 and 2 s, espec i ely. Elemen al analyses we e de e mined in he Mic oanalysis Labo a o ies o he CSIC, Ba celona, Spain. FTIR measu emen s we e ca ied ou in a Jasco 4100 FTIR spec opho ome e , coupled wi h an ATR accesso y Specac MKII, wi h a single e lec ion Golden Ga e diamond, ZnSe lenses and a high s abili y empe a u e d i e Wes 6100+. The abso bance o he sample was eco ded in he ange o 4000-550 cm-1 accumula ing 32 scans o each un. In insic iscosi ies o polyes e s dissol ed in chlo o o m we e measu ed in an An on Paa AMVn Au oma ed Mic o Viscosime e a 25.00±0.01 ºC, using he VisioLab o AMVn so wa e. Gel pe mea ion ch oma og ams we e acqui ed a 35.0 ºC wi h a Wa e s equipmen p o ided wi h a e ac ion-index de ec o . The samples we e ch oma og aphed wi h 0.05 M sodium i luo oace a e-hexa luo oisop opanol Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 67 (NaTFA-HFIP) using a polys y ene-di inylbenzene packed linea column wi h a low a e o 0.5 mL·min-1. Ch oma og ams we e calib a ed agains poly(me hyl me hac yla e) (PMMA) monodispe se s anda ds. The he mal beha io o polyes e s was examined by DSC using a Pe kin Elme DSC Py is 1. DSC da a we e ob ained om 3 o 5 mg samples a hea ing/cooling a es o 10 ºC·min-1 unde a ni ogen low o 20 mL·min-1. Indium and zinc we e used as s anda ds o empe a u e and en halpy calib a ion. The glass- ansi ion empe a u es we e de e mined a a hea ing a e o 20 ºC·min-1 om apidly mel -quenched polyme samples. The ea men o he samples o iso he mal c ys alliza ion expe imen s was he ollowing: he he mal his o y was emo ed by hea ing he sample up o 150 ºC and le a his empe a u e o 5 min, and hen i was cooled a 20 ºC·min-1 o he selec ed c ys alliza ion empe a u e, whe e i was le o c ys allize un il sa u a ion. Iso he mal c ys alliza ion unde he same condi ions was also ca ied ou in an Olympus BX51 Pola izing Op ical Mic oscope coupled o a THMS LINKAM hea ing pla e and a cooling sys em LNP (Liquid Ni ogen Pump). The mog a ime ic analyses we e pe o med unde a ni ogen low o 20 mL·min-1 a a hea ing a e o 10 ºC·min-1, wi hin a empe a u e ange o 30 o 600 ºC, using a Pe kin Elme TGA 6 equipmen . Sample weigh s o abou 10-15 mg we e used in hese expe imen s. Films o mechanical es ing and con ac angle measu emen s we e p epa ed wi h a hickness o ~200 µm by cas ing om a chlo o o m solu ion a a concen a ion o 100 g·L-1. Fo e alua ing mechanical p ope ies, he ilms we e cu in o s ips wi h a wid h o 3 mm, while he dis ance be ween es ing ma ks was 10 mm. The ensile s eng h, elonga ion a b eak and Young’s modulus we e measu ed a a s e ching a e o 30 mm·min-1 on a Zwick 2.5/TN1S es ing machine coupled wi h a comp esso Dalbe DR 150, a 23 ºC. Con ac angles be ween liquid and polyes e ilm su aces we e measu ed by means o a K üss DSA 100 con ac angle measu ing sys em. Angle alues we e egis e ed a e 3 min o d opping 15 µL o ei he wa e o e hylene glycol on o he polyes e su ace a 23 ºC. Scanning elec on mic oscopy (SEM) images we e aken wi h a ield-emission JEOL JSM-7001F ins umen (JEOL, Japan) om uncoa ed samples. 3.2.2.3. Polyme syn hesis Syn hesis o poly(alkylene 2,3:4,5-di-O-me hylene galac a a e)s (PE-nGalx). PE- nGalx polyes e s we e ob ained om an alipha ic α,ω-diol (1,6-hexanediol, 1,8- oc anediol, 1,10-decanediol o 1,12-dodecanediol) and dime hyl 2,3:4,5-di-O-me hylene- galac a a e. Chap e 3 68 P ocedu e A. A mix u e o dime hyl 2,3:4,5-di-O-me hylene-galac a a e and he co esponding diol a a mola a io o 1/1 was p epa ed in a ound-bo om lask, and se e al cycles o a gon and acuum we e applied. The empe a u e was aised o 135 ºC o 30 min wi h s i ing un il homogeniza ion o he mix u e, and hen TBT ca alys (0.5% mol espec o monome s) was added. T anses e i ica ion eac ions we e ca ied ou unde a gon a hea ing a 140 ºC o 4 h ollowed by wo pe iods o 1 h a 150 and 160 ºC, espec i ely. Polycondensa ion eac ions we e pe o med o 2 h a 175 ºC unde acuum (0.6-1.3 mba ). The polyme ized mix u e was hen dissol ed in dichlo ome hane, and he solu ion was pou ed d opwise in o die hyl e he while s i ing. The p ecipi a ed solid was il e ed, washed wi h die hyl e he , and d ied unde acuum. P ocedu e B. The eac ion was pe o med in a h ee-necked, cylind ical-bo om lask equipped wi h a mechanical s i e , a ni ogen inle and a acuum dis illa ion ou le . A 1/1 mola a io o he diol o dime hyl 2,3:4,5-di-O-me hylene-galac a a e and dibu yl in oxide (DBTO) as ca alys (0.4% mol espec o monome s) we e used. The appa a us was en ed wi h ni ogen se e al imes a oom empe a u e o emo e he ai and a oid oxida ion du ing he polyme iza ion. T anses e i ica ion eac ions we e ca ied ou unde a low ni ogen low o a pe iod o 3 h a 140 ºC. Polycondensa ion eac ions we e le o p oceed o 5 h a 140 ºC, unde a 0.03-0.06 mba acuum. Then, he eac ion mix u e was cooled o oom empe a u e, and he a mosphe ic p essu e was eco e ed wi h ni ogen o p e en deg ada ion. Polyme s ob ained we e dissol ed in chlo o o m and p ecipi a ed in excess o me hanol o emo e un eac ed monome s and emaining oligome s. Finally, he polyme was collec ed by il a ion, ex ensi ely washed wi h me hanol and die hyl e he , and d ied unde acuum. PE-6Galx. IR ( ilm),  (cm-1): 1734 (C=O s ), 1260 (C-O asym s , es e ), 1165 (C-O sym s , es e ), 1093 (C-O asym s , ace al), 799 (C-O sym s , ace al), 724 (CH2 ock). 1H NMR (300.1 MHz, CDCl3), δ (ppm): 5.25 and 5.08 (2 s, 4H, 2CH2), 4.61 (m, 2H, 2CH), 4.27 (m, 2H, 2CH), 4.20 ( , 4H, 2CH2), 1.70 (m, 4H, 2CH2), 1.40 (m, 4H, 2CH2). 13C (75.5 MHz, CDCl3), δ (ppm): 170.3 (CO), 96.8, 79.0, 75.3, 65.6, 28.4, 25.4. Anal. Calcd o C14H20O8· 0.25 H2O: C, 52.40; H, 6.37. Found: C, 52.08; H, 6.44. PE-8Galx. IR ( ilm),  (cm-1): 1733 (C=O s ), 1259 (C-O asym s , es e ), 1167 (C-O sym s , es e ), 1092 (C-O asym s , ace al), 796 (C-O sym s , ace al), 719 (CH2 ock). 1H NMR (300.1 MHz, CDCl3), δ (ppm): 5.26 and 5.08 (2s, 4H, 2CH2), 4.61 (m, 2H, 2CH), 4.28 (m, 2H, 2CH), 4.20 ( , 4H, 2CH2), 1.68 (m, 4H, 2 CH2), 1.34 (m, 8H, 4CH2). 13C (75.5 MHz, Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 69 CDCl3), δ (ppm): 170.3 (CO), 96.8, 79.0, 75.2, 65.8, 29.0, 28.5, 25.7. Anal. Calcd o C16H24O8·0.25 H2O: C, 55.09; H, 7.08. Found: C, 55.08; H, 7.02. PE-10Galx. IR ( ilm),  (cm-1): 1734 (C=O s ), 1259 (C-O asym s , es e ), 1168 (C-O s sym, es e ), 1093 (C-O asym s , ace al), 797 (C-O sym s , ace al), 719 (CH2 ock). 1H NMR (300.1 MHz, CDCl3), δ (ppm): 5.25 and 5.07 (2s, 4H, 2CH2), 4.60 (m, 2H, 2CH), 4.28 (m, 2H, 2CH), 4.19 ( , 4H, 2CH2), 1.67 (m, 4H, 2CH2), 1.30 (m, 12H, 6CH2). 13C (75.5 MHz, CDCl3), δ (ppm): 170.3 (CO), 96.8, 79.0, 75.2, 65.9, 29.4, 29.1, 28.5, 25.7. Anal. Calcd o C18H28O8·0.25 H2O: C, 58.05; H, 7.58. Found: C, 57.47; H, 7.47. PE-12Galx. IR ( ilm),  (cm-1): 1734 (C=O s ), 1259 (C-O asym s , es e ), 1168 (C-O sym s , es e ), 1095 (C-O asym s , ace al), 801 (C-O sym s , ace al), 719 (CH2 ock). 1H NMR (300.1 MHz, CDCl3), δ (ppm): 5.25 and 5.07 (2s, 4H, 2CH2), 4.60 (m, 2H, 2CH), 4.28 (m, 2H, 2CH), 4.19 ( , 4H, 2CH2), 1.67 (m, 4H, 2CH2), 1.27 (m, 16H, 8CH2). 13C (75.5 MHz, CDCl3), δ (ppm): 170.3 (CO), 96.8, 79.0, 75.1, 65.9, 29.5, 29.4, 29.2, 28.5, 25.8. Anal. Calcd o C20H32O8·0.25 H2O: C, 59.32; H, 8.09. Found: C, 58.60; H, 8.07. Syn hesis o poly(alkylene adipa e)s (PE-nAd). Dime hyl adipa e and he co esponding alipha ic α,ω-diol (1,6-hexanediol, 1,8-oc anediol, 1,10-decanediol o 1,12- dodecanediol) we e in oduced in a h ee-necked, cylind ical-bo om lask equipped wi h a mechanical s i e , a ni ogen inle and a acuum dis illa ion ou le . A mola excess o 16, 11, 3 and 2% o diol was used o 1,6-hexanediol, 1,8-oc anediol, 1,10-decanediol and 1,12-dodecanediol, espec i ely. The appa a us was en ed wi h ni ogen se e al imes a oom empe a u e, hea ed a 180 ºC unde s i ing un il homogeneiza ion o he mix u e, and hen i anium (IV) bu oxide (TBT) ca alys (0.5% mol espec o dime hyl adipa e) was added. T anses e i ica ion eac ions we e ca ied ou unde a low ni ogen low o a pe iod o 3 h a 180 ºC. The empe a u e was hen inc eased o 200 ºC, and polycondensa ion eac ions we e pe o med a his empe a u e o 3 h, unde a 0.03-0.06 mba acuum. A e ha , he eac ion mix u e was cooled o oom empe a u e, and a mosphe ic p essu e was eco e ed wi h ni ogen o p e en deg ada ion. The solid mass was dissol ed in chlo o o m, and he polyme was p ecipi a ed wi h me hanol, collec ed by il a ion, ex ensi ely washed wi h me hanol and die hyl e he , and d ied unde acuum. PE-6Ad. IR ( ilm),  (cm-1): 1724 (C=O s ), 1256 (C-O asym s , es e ), 1162 (C-O s sym es e ), 733 and 725 (CH2 ock). 1H NMR (300.1 MHz, CDCl3), δ (ppm): 4.06 ( , 4H, 2CH2), 2.32 ( , 4H, 2 CH2), 1.64 (m, 8H, 4CH2), 1.38 (m, 4H, 2CH2). 13C (75.5 MHz, CDCl3), δ Chap e 3 76 he e is a clea indica ion ha he esis ance o hea o PE-nGalx inc eases wi h molecula weigh , and ha he he mal s abili y o hese polyes e s is 20-30 ºC highe han ha o PE-nAd ha ing simila n and molecula weigh alues. The aluable conclusion d awn om his he mog a ime ic s udy is ha he inse ion o Galx uni s in alipha ic polyes e s ins ead o educing hei he mal s abili y con ibu es o a signi ican inc ease in hei decomposi ion empe a u es. Figu e 3.2. TGA aces o PE-nGalx (HMW) and PE-nAd. Linea alipha ic polyes e s wi hou subs i uen s a e cha ac e ized by displaying low glass- ansi ion empe a u es. Ou DSC Tg measu emen s o PE-nAd polyes e s (Table 3.2) con i m indeed such gene al obse a ion; hese polyes e s a e so lexible and end o c ys allize so as ha Tg could be only de e mined o he ela i ely less lexible PE-6Ad which displayed a alue as low as -61 ºC. The eplacemen o he adipa e uni by he Galx uni in PE-nAd inc eased Tg o PE-6Ad by almos 70 ºC and ende s alues o he HMW se ies o PE-nGalx comp ised in he -17 o 6 ºC ange. I is well-known ha he inco po a ion o igid s uc u es such as a oma ic o alipha ic cyclic uni s in a polyes e chain gi es ise o a d ama ic inc ease in Tg (B and up e al., 1999). Polyes e s wi h Mn in he 10,000-23,000 g·mol-1 ange made om isoso bide and alipha ic dica boxylic acids wi h leng hs simila o he alkanediols used in his wo k a e epo ed o ha e Tg be ween -10 and 10 ºC (B aun and Be gmann, 1992), which a e pe ec ly compa able o hose displayed by HMW PE-nGalx. I seems he e o e ha Galx exe s a simila e ec as Is on Tg, which is a he s iking because a highe s i ness should be expec ed o he almos plana used i e-membe ed e ahyd o u ane ings han o he pucke ed and con o ma ionally in e con e ible 5,5’-bis(1,3-dioxolane) s uc u e. Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 77 Table 3.2. The mal and mechanical p ope ies o PE-nGalx and PE-nAd polyes e s. Polyes e TGA DSC Tensile es Fi s hea inge Coolinge Second hea inge ºT5%a Tdb W c Tgd Tm ΔHm Xcg Tc ΔHc Tc ΔHc Tm ΔHm Xcg E   (ºC) (ºC) (%) (ºC) (ºC) (J·g-1) (ºC) (J·g-1) (ºC) (J·g-1) (ºC) (J·g-1) (MPa) (MPa) (%) LMW PE-6Galx 280 356 18 -4 61/73 34.8 - - - - - - - n.d. n.d. n.d. PE-8Galx 315 385 13 -17 52/66/74 44.3 - - - - - - - n.d. n.d. n.d. PE-10Galx 294 375 12 -22 57/75 48.5 - - 31 30.4 78 31.8 - n.d. n.d. n.d. PE-12Galx 276 369 10 -19 77 42.7 46 28.6 - - 79 28.2 - n.d. n.d. n.d. HMW PE-6Galx 325 398 13 6 51/70/73 15.7 - - - - - - - 154 13 55 PE-8Galx 320 392 15 -8 52/69/73 24.5 - - - - - - - 157 12 50 PE-10Galx 323 387 16 -13 53/77/81 25.0 - - 40 20.1 81 20.2 - 151 13 60 PE-12Galx 327 387 13 -17 86 28.9 35 26.3 - - 86 26.9 - 153 13 60 PE-6Ad 300 367 1 -61 56 100.5 0.60 40 69.8 - - 57 73.1 0.44 100 7 201 PE-8Ad 297 372 2 n.d. 67 108.4 0.68 46 84.6 - - 68 85.3 0.53 88 8 210 PE-10Ad 305 363 1 n.d. 73 109.2 0.70 58 99.2 - - 74 99.7 0.64 95 7 203 PE-12Ad 311 375 1 n.d. 75 118.8 0.71 63 102.5 - - 75 109.1 0.65 87 6 215 aTempe a u e a which 5 % weigh loss was obse ed. bTempe a u e o maximum deg ada ion a e. cRemaining weigh a 600 ºC. dGlass- ansi ion empe a u e aken as he in lec ion poin o he hea ing DSC aces o mel -quenched samples eco ded a 20 ºC·min-1. eMel ing (Tm) and c ys alliza ion (Tc) empe a u es, and mel ing (ΔHm) and c ys alliza ion (ΔHc) en halpies measu ed by DSC a hea ing/cooling a es o 10 ºC·min-1. Mul iple mel ing peak. g C ys allini y index based on 100 % c ys alline polyes e : ΔHmº PE-6Ad = 38.1 KJ·mol-1; ΔHmºPE-8Ad = 41.0 KJ·mol-1; ΔHmºPE-10Ad = 44.0 KJ·mol-1; ΔHmºPE-12Ad = 52.0 KJ·mol-1 (Maglio e al., 1979). Chap e 3 78 I seems ha he ela i ely elonga ed shape o Galx will allow a close packing o he polyme chains, which implies less ee olume and acco dingly a highe Tg. Wi h ega d o he in luence o he cons i u ion o PE-nGalx on Tg, he e ec s obse ed we e hose acco ding o expec a ions; Tg o he LMW se we e a ound 10 ºC lowe han o HMW se , and wi hin each se , i dec eased almos s eadily wi h inc easing alues o n. The mel ing-c ys alliza ion beha io o he polyes e s was cha ac e ized by DSC and he collec ed da a a e ga he ed in Table 3.2. PE-nAd polyes e s a e highly c ys alline polyme s displaying mel ing empe a u es be ween 56 and 75 ºC and mel ing en halpies g ea e han 100 J·g-1 which co espond o c ys allini y indexes o 0.6-0.7, bo h pa ame e s inc easing s eadily wi h he alue o n. These unsubs i u ed polyes e s c ys allized e y as when cooled om he mel wi h a eco e y o abou 70-90% o hei ini ial c ys allini y and almos exac eplica ion o hei mel ing empe a u es. PE-nGalx a e also c ys alline bu hey show ema kable di e ences compa ed o PE-nAd ha e idence he de imen al in luence exe ed by he diace alized galac a a e esidue on c ys allini y and c ys allizabili y. The hea ing DSC aces o PE-nGalx (HMW) a e depic ed in Figu e 3.3. Those ob ained om samples coming di ec ly om syn hesis displayed wide endo he ms consis ing o se e al mel ing peaks indica i e o a de ec i e c ys alliza ion o he polyes e . T aces wi h simila p o iles we e ob ained om PE-nGalx (LMW), which a e no shown he e bu can be inspec ed on Annex B. Annealing o p is ine samples o PE- nGalx (HMW) a empe a u es be ween 60 and 75 ºC o 12 h homogenized he c ys alline mo phology; in ac , mel ing o he annealed polyme ook place sha ply and a high empe a u es, as co esponds o a single popula ion o c ys alli es o well-de ini e size. Tm o PE-nGalx (measu ed on annealed samples) a e wi hin he 70-85 ºC ange, which is no a om he PE-nAd mel ing empe a u e ange, wi h alues inc easing egula ly wi h he alue o n. Whe eas nei he molecula weigh no cons i u ion seem o no ably a ec mel ing empe a u es, hei in luence on mel ing en halpy appea s o be e y ema kable. As can be seen in Table 3.2,  Hm o PE-nGalx (HMW) polyme s a e se e al imes smalle han hose o PE-nAd and app oxima ely he hal o he alues obse ed o PE-nGalx (LMW). Las ly, jus o no e ha , wi h ega d o polyes e s made om isoso bide epo ed in he li e a u e (Okada e al., 2000), mel ing o PE-nGalx akes place a highe empe a u es bu wi h simila associa ed en halpies. Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 79 Figu e 3.3. DSC mel ing aces o samples o PE-nGalx (HMW) coming di ec ly om syn hesis (le ) and annealed ( igh ) a (a) 75 ºC o 12 h, (b) 70 ºC o 12 h, (c) 65 ºC o 12 h and (d) 60 ºC o 12 h. A di e ence wi h PE-nAd, PE-nGalx a e in gene al unable o c ys allize om he mel . In ac , only PE-12Galx, bo h LMW and HMW, which is he highes lexible PE- nGalx, showed exo he mal c ys alliza ion peaks a he cooling DSC aces; he c ys allized polyme s display simila Tm bu signi ican ly lowe  Hm han hei espec i e p is ine samples. Gi en he ex eme ele ance o his p ope y ega ding polyme p ocessing, he iso he mal c ys alliza ion o LMW and HMW PE-12Galx was kine ically analyzed a di e en empe a u es by using he A ami app oach o app aise quan i a i ely he e ec o molecula weigh on c ys allizabili y. The ela i e c ys allini y s. ime plo as well as he double loga i hmic plo o bo h low and high molecula weigh PE- 12Galx a e compa ed in Figu e 3.4, and kine ics da a ex ac ed om hese esul s a e ga he ed in Table 3.3. The conclusions ha may be d awn om he kine ics s udy a e acco ding o expec a ions. LMW PE-12Galx c ys allized much as e han HMW PE- Table 3.3. Iso he mal c ys alliza ion da a o LMW and HMW PE-12Galx. Tc 0 1/2 n -logk Tm Polyes e (ºC) (min) (min) (ºC) PE-12Galx (LMW) 50 0.28 2.08 2.28 0.75 78.2 55 0.38 3.16 2.51 1.27 78.5 60 0.41 5.16 2.96 2.14 79.2 PE-12Galx (HMW) 50 0.35 2.36 2.80 1.04 81.9 55 0.40 3.74 2.92 1.76 82.5 60 0.45 8.66 2.99 2.90 83.1 Chap e 3 80 12Galx, and in bo h cases c ys alliza ion a e diminished as empe a u e inc eased e ealing ha wi hin he s udied empe a u e ange, he p ocess is domina ed by nuclea ing e ec s. Fu he mo e, he in luence o empe a u e on c ys alliza ion a e is mo e p onounced in he case o high molecula weigh PE-12Galx. Figu e 3.4. Iso he mal c ys alliza ion o PE-12Galx a he indica ed empe a u es. a) Rela i e c ys allini y s. ime plo o PE-12Galx (LMW). b) Log-log plo o PE-12Galx (LMW). c) Rela i e c ys allini y s. ime plo o PE-12Galx (HMW). d) Log-log plo o PE-12Galx (HMW). A p elimina y e alua ion o he mechanical beha io o PE-nGalx (HMW) compa ed o PE-nAd was made by ensile es ing a oom empe a u e. The ob ained s ess-s ain cu es a e depic ed in Figu e 3.5, and he mechanical pa ame e s ex ac ed om hem a e lis ed in Table 3.2. The elas ic modulus alues o PE-nGalx oscilla e in he 150-160 MPa ange, whe eas PE-nAd ha e moduli in he 85-100 MPa ange. Tensile s eng hs each alues o 12-13 MPa and 6-8 MPa o PE-nGalx and PE-nAd, espec i ely, whe eas elonga ions a b eak a e a ound 50 and 200%. The highe igidi y and lowe duc ili y obse ed o PE-nGalx seem o be he logical consequence o he highe Tg displayed by hese polyes e s compa ed o PE-nAd, which doub less is due o he p esence o he bicyclic ace al s uc u e in he polyme chain. Howe e , no co ela ion be ween he mechanical pa ame e s and he leng h o polyme hylene segmen becomes Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 81 appa en , he small obse ed di e ences alling wi hin he accep able expe imen al e o limi . Figu e 3.5. S ess-s ain cu es o PE-nGalx (HMW) and PE-nAd. 3.2.3.3. Hyd oly ic deg ada ion and biodeg ada ion I is well-known ha polycondensa es o syn he ic o igin a e esis an o hyd olysis o e en appa en ly ine o long ime in e als when incuba ed unde physiological condi ions. I has been epea edly shown ha he inco po a ion o suga esidues in polyes e s, polyamides o polyu e hanes enhances he suscep ibili y o he polyme o hyd olysis (Ruiz-Donai e e al., 1995; Zamo a e al., 2006; De Paz e al., 2007). Bo h alipha ic and a oma ic polyes e s con aining isoso bide we e epo ed o be hyd olyzed a highe a es han hei unsubs i u ed analogous when incuba ed unde simila condi ions. Okada e al. ocused on he biodeg adabili y o polyes e s made om alipha ic dica boxylic acids and 1,4:3,6 dianhyd ohexi ols (Okada e al., 1996, 1997 and 1999), and concluded ha all o hem we e biodeg aded o an ex en ha la gely depended on he con igu a ion o he anhyd oaldi ol. To e alua e he e ec o Galx on he hyd olysis o alipha ic polyes e s, a compa a i e s udy using PE-8Ad and PE-8Galx was ca ied ou in his wo k. Samples o he wo polyme s we e incuba ed in aqueous bu e s a pH 2.0, 7.4 and 10.5 a oom empe a u e o wo mon hs, and he e olu ion o he deg ada ion p ocess was ollowed by measu ing he weigh loss and he molecula weigh o he esidual polyme . The esul s o his compa a i e s udy a e p esen ed in Figu e 3.6. The p o iles ob ained o PE-8Ad indica e ha he e is no loss o mass and ha he dec ease in molecula weigh is p ac ically negligible a any pH. On he con a y, PE- 8Galx showed an app eciable weigh loss ha was minimum (4%) a pH 7.4 and Chap e 3 82 maximum (~15%) a pH 2.0, as well as a signi ican dec easing o bo h Mw and Mn, whe eas polydispe si y emained almos cons an . Figu e 3.6. a) Remaining weigh s. hyd oly ic deg ada ion ime o PE-8Galx (HMW) and PE-8Ad a pH 2.0, 7.4 and 10.5. (b) Changes in Mw and Mn (solid symbols) and polydispe si y index (emp y symbols) s. incuba ion ime o PE-8Galx. (c) Changes in Mw and Mn (solid symbols) and polydispe si y index (emp y symbols) s. incuba ion ime o PE-8Ad. Figu e 3.7. Deg ada ion o PE-8Galx (HMW) and PE-8Ad in he p esence o lipases om Pseudomonas luo escens and po cine panc eas, and wi hou lipase. (a) Remaining weigh s. deg ada ion ime. (b) Changes in Mw and Mn (solid symbols) and polydispe si y index (emp y symbols) s. incuba ion ime o PE-8Galx. (c) Changes in Mw and Mn (solid symbols) and polydispe si y index (emp y symbols) s. incuba ion ime o PE-8Ad. Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 83 A simila s udy was hen pe o med wi h PE-8Ad and PE-8Galx bu adding ei he P. luo escens o po cine panc eas lipases o he incuba ion medium a pH 7.4, and esul s ob ained o e an incuba ion pe iod o h ee weeks a 37 ºC a e p esen ed in Figu e 3.7. In he p esence o lipases, bo h PE-8Ad and PE-8Galx showed app eciable g ea e weigh losses and molecula weigh educ ions han in he absence o enzymes indica ing ha he hyd olysis o bo h polyes e s was speeded by lipases. The ac i i y o he wo lipases was no no ewo hy di e en as nei he was he sensi i i y o he wo polyme s o he enzyma ic ac ion; in ac , a compa ison o he plo s in Figu e 3.7 clea ly e eals ha he g ea e deg ee o biodeg ada ion appa en ly obse ed o PE-8Galx is he only consequence o i s lowe in insic s abili y agains hyd olysis. The changes aking place in he mic omo phology o PE-8Ad and PE-8Galx due o he deg ada ion p ocess we e e ealed by SEM analysis as i is illus a ed in Figu e 3.8. The su ace o a esh ac u ed p is ine sample o PE-8Ad exhibi ed a sphe uli ic ex u e, which became mo e i id a e incuba ion in wa e a pH 2.0, p obably due o he emo al o some in a- and in e sphe uli ic amo phous ma e ial. Upon incuba ion in he p esence o po cine panc eas lipase, he su ace became smoo he and de eloped some small c acks, indica ing ha a ce ain deg ada ion in bulk happened. The esul s ob ained in he pa allel analysis ca ied ou on PE-8Galx we e clea ly di e en . In his case, he ini ial su ace did no display any ea u e o c ys alline mo phology, and a e incuba ion in acidic wa e , plen y o holes and g oo es appea ed delinea ing wha seems o be a ex u e made o ela i ely small impinging sphe uli es. In he p esence o lipase, la ge c acks causing he o al ac u e o he ma e ial became appa en . The SEM pic u es suppo he conclusion ha PE-8Galx becomes mo e se e ely deg aded han PE-8Ad, bo h in he p esence and in he absence o lipases, and ha he deg ada ion p ocess does no ollow he same mechanism in each case. Chap e 3 84 Figu e 3.8. SEM mic og aphs o PE-8Ad ( op) and PE-8Galx (HMW) (bo om). (a, a’) Ini ial sample. (b, b’) A e incuba ion a pH=2.0 o 56 days. (c, c`) A e incuba ion in he p esence o lipase om po cine panc eas a pH=7.4 o 21 days. Figu e 3.9. Compa ed 1H NMR spec a o PE-8Galx (HMW) a e incuba ion a pH=2.0 o 56 days ( op) and ini ial sample (bo om). The a ow indica es he signal a ising om -CH2OH end g oups ha appea upon hyd olysis o he main chain es e g oup. Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 85 Figu e 3.10. 1H NMR spec a in D2O o he p oduc esul ing a e incuba ion o dime hyl 2,3:4,5-di- O-me hylene galac a a e a pH 2.0 o h ee mon hs a oom empe a u e ( op) and o ini ial sample in CDCl3 (bo om). Finally, a NMR s udy was made o explo e how he polyes e chain is deg aded a he molecula le el. The changes aking place in he 1H NMR spec um o a sample o PE-8Galx upon incuba ion in aqueous bu e a pH 2.0 a e shown in Figu e 3.9. All he signals p esen in he o iginal spec um emained unal e ed a e deg ada ion, and he only changes obse ed a e incuba ion was he appea ing o a small signal co esponding o hyd oxyme yl g oup a 3.6 ppm. 1NMR spec a o PE-8Galx samples incuba ed a pH 7.4 and 10.5 a o ded simila esul s, indica ing ha deg ada ion p oceeded by spli ing o he ela i ely weak es e g oup wi hou modi ica ion o he polyme chain s uc u e. The esul is a he s iking since he ace al g oup is known o be sensi i e o acidic condi ions (Smi h and Ma ch, 2007) and he opening o he dioxolane ings should ha e he e o e been expec ed o happen in some ex en . To check he s abili y o he diace al s uc u e, dime hyl 2,3:4,5-di-O-me hylene-galac a a e was incuba ed a oom empe a u e in aqueous bu e a pH 2.0, 7.4 and 10.5. The ini ial powde ed nonsoluble sample dissol ed as deg ada ion p oceeded, and he NMR analysis o he solu ion a e h ee mon hs e ealed ha hyd olysis o he es e g oups had happened almos quan i a i ely a bo h pH 2.0 and 10.5, whe eas a pH 7.4 abou 5% o he ini ial dies e was s ill emaining. Wha was eally ema kable is ha he ace al g oup s ayed in ac a e he ea men wi h wha e e we e he incuba ion condi ions. The Chap e 3 92 3.3.2. Expe imen al sec ion 3.3.2.1. Ma e ials Dime hyl 2,3:4,5-di-O-me hylene-galac a a e was syn hesized ollowing he p ocedu e epo ed by S acey e al. (Bu le e al., 1958). The eagen s 1,12-dodecanediol (99%), 1,6-hexanediol (97%) and dime hyl adipa e (> 99%), and he ca alys dibu yl in oxide (DBTO, 98%) we e pu chased om Sigma-Ald ich. Sol en s used o pu i ica ion and cha ac e iza ion, as chlo o o m and me hanol, as well as sol en s used in he solubili y essays, we e pu chased om Pan eac and hey all we e o ei he echnical o high-pu i y g ade. All he eagen s and sol en s we e used as ecei ed wi hou u he pu i ica ion. 3.3.2.2. Gene al me hods 1H and 13C NMR spec a we e eco ded on a B uke AMX-300 spec ome e a 25.0 ºC ope a ing a 300.1 and 75.5 MHz, espec i ely. Polyes e s we e dissol ed in deu e a ed chlo o o m o in deu e a ed benzene, and spec a we e in e nally e e enced o e ame hylsilane (TMS). Abou 10 and 50 mg o sample dissol ed in 1 mL o sol en we e used o 1H and 13C NMR, espec i ely. Six y- ou scans we e acqui ed o 1H and 1,000-10,000 o 13C wi h 32 and 64-K da a poin s as well as elaxa ion delays o 1 and 2 s, espec i ely. FTIR measu emen s we e ca ied ou in a Jasco 4100 FTIR spec opho ome e , coupled wi h an ATR accesso y Specac MKII, wi h a single e lec ion Golden Ga e diamond, ZnSe lenses and a high s abili y empe a u e d i e Wes 6100+. The abso bance o he sample was eco ded in he ange o 4000-550 cm-1 accumula ing 32 scans o each un. In insic iscosi ies o polyes e s dissol ed in chlo o o m we e measu ed in an An on Paa AMVn Au oma ed Mic o Viscosime e a 25.00±0.01 ºC, using he VisioLab o AMVn so wa e. Gel pe mea ion ch oma og ams we e acqui ed a 35.0 ºC wi h a Wa e s equipmen p o ided wi h a e ac ion-index de ec o . The samples we e ch oma og aphed wi h 0.05 M sodium i luo oace a e-hexa luo oisop opanol (NaTFA-HFIP) using a polys y ene-di inylbenzene packed linea column wi h a low a e o 0.5 mL·min-1. Ch oma og ams we e calib a ed agains poly(me hyl me hac yla e) (PMMA) monodispe se s anda ds. The he mal beha io o polyes e s was examined by DSC using a Pe kin Elme DSC Py is 1. DSC da a we e ob ained om 3 o 5 mg samples a hea ing/cooling a es o 10 ºC·min-1 unde a ni ogen low o 20 mL·min-1. Indium and zinc we e used as s anda ds o empe a u e and en halpy calib a ion. The glass- Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 93 ansi ion empe a u es we e de e mined a a hea ing a e o 20 ºC·min-1 om apidly mel -quenched polyme samples. The ea men o he samples o iso he mal c ys alliza ion expe imen s was he ollowing: he he mal his o y was emo ed by hea ing he sample up o 150 ºC and le a his empe a u e o 5 min, and hen i was cooled a 20 ºC·min-1 o he selec ed c ys alliza ion empe a u e, whe e i was le o c ys allize un il sa u a ion. Fo mo phological s udy, iso he mal c ys alliza ions unde he same condi ions we e ca ied ou in an Olympus BX51 Pola izing Op ical Mic oscope coupled o a THMS LINKAM hea ing pla e and a cooling sys em LNP (Liquid Ni ogen Pump). The mog a ime ic analyses we e pe o med unde a ni ogen low o 20 mL·min-1 a a hea ing a e o 10 ºC·min-1, wi hin a empe a u e ange o 30 o 600 ºC, using a Pe kin Elme TGA 6 equipmen . Sample weigh s o abou 10-15 mg we e used in hese expe imen s. Films o mechanical es ing measu emen s we e p epa ed wi h a hickness o ~200 µm by cas ing om chlo o o m solu ion a a polyme concen a ion o 100 g·L-1; he ilms we e hen cu in o s ips wi h a wid h o 3 mm while he dis ance be ween es ing ma ks was 10 mm. The ensile s eng h, elonga ion a b eak and Young’s modulus we e measu ed a a s e ching a e o 30 mm·min-1 on a Zwick 2.5/TN1S es ing machine coupled wi h a comp esso Dalbe DR 150, a 23 ºC. Powde X- ay di ac ion pa e ns we e eco ded on he INEL CPS-120 di ac ome e in Debye-Sche e con igu a ion using he Cu-Kα adia ion o wa eleng h 0.1542 nm om powde ed samples coming di ec ly om syn hesis. Wide-angle X- ay sca e ing o aniso opic samples was pe o med in he synch o on beamline A2 a HASYLAB, Hambu g, Ge many. Sca e ing pa e ns we e collec ed by a wo-dimensional posi ion sensi i e ma ccd 165 de ec o . Se ies o sca e ing pa e ns we e eco ded a 30 s cycle imes including 20 s o exposu e. 3.3.2.3. Polyme syn hesis The homopolyes e s PE-12Galx, PE-12Ad, PE-6Galx and PE-6Ad we e syn hesized ollowing he p ocedu e ecen ly epo ed by La illa e al. (La illa e al., 2011 -Subchap e 3.2-). PE-nAdxGalxy copolyes e s we e ob ained om he chosen alipha ic α,ω-diol (ei he 1,6-hexanediol o 1,12-dodecanediol) and a mix u e o dime hyl 2,3:4,5- di-O-me hylene-galac a a e and dime hyl adipa e wi h he selec ed composi ion. The eac ion was pe o med in a h ee-necked, cylind ical-bo om lask equipped wi h a mechanical s i e , a ni ogen inle and a acuum dis illa ion ou le . A 5% mola excess o diol o he dies e mix u e, and dibu yl in oxide (DBTO) as ca alys (0.8% w/w espec o monome s) we e used. The appa a us was en ed wi h ni ogen se e al imes a oom Chap e 3 94 empe a u e in o de o emo e he ai and a oid oxida ion du ing he polyme iza ion. The anses e i ica ion eac ion was ca ied ou unde a low ni ogen low a 140 ºC o 3 h. The polycondensa ion eac ion was le o p oceed a 140 ºC o 5 h, unde a 0.03-0.06 mba acuum. Then, he eac ion mix u e was cooled o oom empe a u e, and he a mosphe ic p essu e was eco e ed wi h ni ogen o p e en deg ada ion. The esul ing polyme s we e dissol ed in chlo o o m and p ecipi a ed in excess o me hanol in o de o emo e un eac ed monome s and o med oligome s. Finally, he polyme was collec ed by il a ion, ex ensi ely washed wi h me hanol, and d ied unde acuum. PE-12AdxGalxy. IR ( ilm),  (cm-1): 1730 (C=O s ), 1260 (C-O asym s , es e ), 1160 (C-O sym s , es e ), 1095 (C-O asym s , ace al), 800 (C-O sym s , ace al), 730 and 720 (CH2 ock). 1H NMR (300.1 MHz, CDCl3), δ (ppm): 5.25 and 5.05 (2s, Galx, 2CH2), 4.60 (m, Galx, 2CH), 4.28 (m, Galx, 2CH), 4.19 ( , Galx, 2CH2), 4.06 ( , Ad, 2CH2), 2.32 ( , Ad, 2CH2), 1.65 (m, Ad, Galx, 6CH2), 1.28 (m, Ad, Galx, 16CH2). 13C NMR (75.5 MHz, C6D6), δ (ppm): 172.6 (CO), 170.3 (CO), 97.1, 79.9, 76.3, 65.6, 64.3, 34.1, 29.9, 29.8, 29.6, 29.5, 29.2, 28.9, 26.4, 26.1, 24.9. PE-6AdxGalxy. IR ( ilm),  (cm-1): 1730 (C=O s ), 1260 (C-O asym s , es e ), 1160 (C-O sym s , es e ), 1095 (C-O asym s , ace al), 800 (C-O sym s , ace al), 730 and 720 (CH2 ock). 1H NMR (300.1 MHz, CDCl3), δ (ppm): 5.25 and 5.05 (2s, Galx, 2CH2), 4.60 (m, Galx, 2CH), 4.28 (m, Galx, 2CH), 4.20 ( , Galx, 2CH2), 4.06 ( , Ad, 2CH2), 2.32 ( , Ad, 2CH2), 1.65 (m, Ad, Galx, 6CH2), 1.39 (m, Ad, Galx, 4CH2). 13C NMR (75.5 MHz, CDCl3), δ (ppm): 173.4 (CO), 170.3 (CO), 96.8, 79.0, 75.3, 65.6, 64.3, 33.9, 28.5, 28.4, 25.5, 25.4, 24.4. 3.3.3. Resul s and discussion 3.3.3.1. Syn hesis and chemical s uc u e The syn hesis o PE-12AdxGalxy and PE-6AdxGalxy copolyes e s was ca ied ou by eac ing mix u es o dime hyl adipa e and Galx in he selec ed p opo ions, wi h 1,12- dodecanediol o 1,6-hexanediol espec i ely, as depic ed in Scheme 3.4. Polycondensa ion condi ions we e simila o hose p e iously applied by us in he syn hesis o PE-nAd and PE-nGalx homopolyes e se ies, which included he wo pai s o pa en homopolyes e s (PE-12Ad/PE12Galx and PE-6Ad/PE-6Galx) used in his wo k as Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 95 e e ences. Thus, eac ions we e pe o med in he mel and in he o al absence o sol en s, and unde a p og essi ely diminishing eac ion p essu e in o de o acili a e he eleasing o ola ile by-p oduc s. As be o e, he ca alys DBTO was used ins ead o he mo e amilia TBT, which allowed o keep he empe a u e a 140 ºC along he whole polycondensa ion p ocess minimizing he decomposi ion o he mally sensi i e suga compounds. By hese means, copolyes e s could be p epa ed as whi e powde s wi h accep able molecula weigh s in yields close o 90%. The syn hesis esul s ob ained o he wo copolyes e se ies a e ga he ed in Table 3.4 oge he wi h da a p e iously epo ed o hei co esponding pa en homopolyes e s. Scheme 3.4. Polyme iza ion eac ions leading o PE-nAdxGalxy copolyes e s. The in insic iscosi ies o he copolyes e s oscilla e be ween 0.5 and 0.8 dL·g-1, wi h he lowe alues being gene ally obse ed o he PE-6 se ies. The GPC analysis a o ded Mn alues comp ised in he ~14,000-16,000 g·mol-1 ange wi h polydispe si ies be ween 2 and 3. In addi ion o GPC, he Mn o he polyes e s was es ima ed by 1H NMR (end-g oup analysis) and a e y good ag eemen was ound be ween alues p o ided by he wo echniques. The chemical cons i u ion and composi ion o he esul ing polycondensa es we e asce ained by in a ed and 1H NMR spec oscopies. In a ed spec a we e e y simila o he wo se ies showing he ypical ca boxyla e (~1730, ~1260 and ~1170 cm-1) and cyclic ace al (~1095 and ~800 cm-1) s e ching abso p ions as well as he me hylene s e ching (3000-2850 cm-1), bending (~1470 cm-1) and ocking (~730-720 cm-1) bands wi h in ensi ies acco ding o composi ions. Chap e 3 96 Table 3.4. Molecula weigh s and composi ions o PE-12AdxGalxy and PE-6AdxGalxy copolyes e s. Copolyes e Molecula weigh Mola composi ion Solubili ye Feed Copolyes e d Yield (%) [η]a Mnb Mnc Mwc Ðc XAd XGalx XAd XGalx H2O E OH E 2O DMSO NMP DMF THF CHCl3 HFIP TFA PE-12Ad 91 0.66 16,000 16,900 38,000 2.2 100 0 100 0 - - - + + PE-12Ad90Galx10 90 0.73 15,200 14,200 37,000 2.6 90 10 89.6 10.4 - - - + + PE-12Ad70Galx30 88 0.76 16,900 16,300 45,600 2.8 70 30 68.2 31.8 - - + + + PE-12Ad50Galx50 89 0.68 15,500 14,300 38,700 2.7 50 50 48.6 51.4 - - + + + PE-12Ad30Galx70 89 0.72 16,300 15,500 42,000 2.7 30 70 28.2 71.8 - - + + + PE-12Ad10Galx90 90 0.69 15,800 14,500 37,800 2.6 10 90 9.6 90.4 - - + + + PE-12Galx 91 0.81 20,400 16,400 41,200 2.5 0 100 0 100 - - + + + PE-6Ad 92 0.68 23,800 21,700 42,200 1.9 100 0 100 0 - - - + + PE-6Ad90Galx10 90 0.80 18,600 16,200 45,300 2.8 90 10 89.0 11.0 - - - + + PE-6Ad70Galx30 88 0.67 17,900 15,100 39,400 2.6 70 30 68.2 31.8 - - + + + PE-6Ad50Galx50 89 0.52 16,500 15,400 35,000 2.3 50 50 48.3 51.7 - - + + + PE-6Ad30Galx70 88 0.53 16,900 16,000 36,200 2.3 30 70 28.1 71.9 - - + + + PE-6Ad10Galx90 91 0.62 17,200 15,300 38,100 2.5 10 90 11.7 88.3 - - + + + PE-6Galx 90 0.51 16,800 15,100 34,700 2.3 0 100 0 100 - - + + + aIn insic iscosi y in dL·g-1 measu ed in chlo o o m a 25 ºC. b Numbe -a e age molecula weigh in g·mol-1 de e mined by 1H NMR end g oup analysis. c Numbe and weigh -a e age molecula weigh s in g·mol-1 and dispe si ies measu ed by GPC in HFIP agains PMMA s anda ds.d Mola composi ion de e mined by in eg a ion o he 1H NMR spec a.e (-) Insoluble, (+) soluble. Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 97 The 1H NMR spec a co obo a ed he chemical s uc u e o he copolyes e s wi h all signals being co ec ly assigned o he di e en p o ons con ained in hei epea ing uni s (Figu e 3.11). No signi ican aces o o he signals indica i e o impu i ies we e de ec ed in hese spec a. Fu he mo e, in eg a ion o he p o on signals a ising om Ad and Galx uni s led o quan i y he composi ion o he copolyes e s in such uni s. Da a p o ided by his analysis a e gi en in Table 3.4, whe e i can be seen ha he copolyes e s composi ions a e essen ially simila o hose o hei espec i e eeds. A close compa ison o he composi ion alues e eals howe e , ha he con en o he copolyme s in adipic uni s is sligh ly lowe han in hei co esponding eed in mos cases. Such p e e en ial inco po a ion o he Galx uni s may be a ibu ed o sligh losses o he ela i ely ola ile dime hyl adipa e aking place du ing polycondensa ion. Figu e 3.11. Compa ed 1H NMR spec a o PE-12AdxGalxy and PE-6AdxGalxy copolyes e s. The mic os uc u e o PE-12AdxGalxy copolyes e s was de e mined by 13C NMR analysis and he spec um egis e ed om PE-12Ad50Galx50 is shown in Figu e 3.12 o illus a ion. The signals o all he magne ically di e en ca bons con ained in he epea ing uni s o he copolyes e s appea well esol ed in he 13C NMR spec a and in pa icula hose a ising om he me hylene ca bons o he diol, which come ou o be sensi i e o sequence e ec s a he dyad le el. As shown in Figu e 3.13 o he case o he PE- 12AdxGalxy, se ies, each esonance o he wo δ-me hylene ca bons appea s spli so ha ou peaks a e seen in he 29.4-29.7 ppm chemical shi in e al co esponding o he h ee ypes o dyads (AdAd, AdGalx and GalxAd, GalxGalx) ha a e easible along he copolyes e chain. The dyad con en s we e de e mined by a ea in eg a ion p o ided ha Chap e 3 98 elaxa ion imes o he in ol ed ca bon a oms a e compa able. The plo o he con en in each ype o dyad as a unc ion o he copolyes e s composi ion e eals ha he mic os uc u e o he copolyes e s is clea ly s a is ical and andomness was calcula ed o be qui e nea uni y in all cases. The s a is ical alues ob ained om his mic os uc u e analysis a e gi en in Table 3.5. Simila expe imen al esul s (no shown) we e ob ained in he analysis o he PE-6AdxGalxy so he same conclusions ega ding mic os uc u e we e d awn o his se ies. Figu e 3.12. 13C NMR spec um o PE-12Ad50Galx50 copolyes e . Figu e 3.13. 13C NMR signals used o he mic os uc u e analysis o PE-12AdxGalxy copolyes e s (le ) wi h indica ion o he dyads o which hey a e assigned ( igh ). Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 99 Table 3.5. Mic os uc u e analysis o PE-12AdxGalxy copolyes e s. Copolyes e Dyads (mol %) Numbe A e age Sequence Leng hs Randomness AA AG/GA GG nAd nGalx R PE-12Ad90Galx10 81.17 17.34 1.50 10.36 1.17 0.95 PE-12Ad70Galx30 48.15 39.98 11.87 3.41 1.59 0.92 PE-12Ad50Galx50 22.71 51.43 25.86 1.88 2.01 1.03 PE-12Ad30Galx70 9.97 37.06 52.97 1.54 3.85 0.91 PE-12Ad10Galx90 2.30 15.28 82.42 1.30 11.79 0.85 3.3.3.2. The mal p ope ies The he mal beha io o bo h PE-12AdxGalxy and PE-6AdxGalxy copolyes e s has been sys ema ically s udied by TGA and DSC aking as e e ence hei pa en homopolyes e s con aining exclusi ely adipa e o 2,3:4,5-di-O-me hylene galac a a e uni s. Fi s ly, he he mal s abili y was e alua ed by TGA unde an ine a mosphe e. The weigh loss s. empe a u e plo s egis e ed o he wo se ies a e shown in Figu e 3.14 e idencing he simili ude o beha io among he membe s o each se ies. As i is illus a ed in Figu e 3.15 o he speci ic cases o PE-12Ad70Galx30 and PE-12Ad10Galx90, he he mal decomposi ion happens h ough wo o h ee s eps depending on he copolyes e composi ion. In all cases he main s ep akes place wi h a maximum a e Td loca ed in he 350-400 ºC empe a u e ange wi h alues oughly inc easing wi h he con en in Galx uni s, and in ol ing weigh losses up o 90% o he ini ial weigh . A second decomposi ion s ep aking place a empe a u es a ound 450 ºC and in ol ing weigh losses o 30% as maximum is in a iably accompanying he main peak. The copolyes e s highly en iched in Galx uni s as well as Galx homopolyes e s s ill show a hi d decomposi ion s ep nea below 350 ºC wi h weigh losses less han 15%. The concluding ema k ha can be d awn om he TGA analysis is ha in gene al he eplacemen o adipa e by Galx uni s inc eases he he mal s abili y o he polyes e s in he wo se ies. Such a end is no applicable howe e o copolyes e s wi h e y high con en s in suga uni s ( 90%), which s a o decompose a empe a u es below 350 ºC, appa en ly due o he p esence o long sequences o Galx uni s. Chap e 3 100 Figu e 3.14. TGA aces o PE-12AdxGalxy (a) and PE-6AdxGalxy (b) copolyes e s. Figu e 3.15. TGA aces (solid lines) and de i a i e cu es (dashed lines) o PE-12Ad70Galx30 and PE-12Ad10Galx90 copolyes e s. Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 101 The DSC analysis e ealed signi ican changes in he mel ing and glass- ansi ions o PE-12Ad and PE-6Ad polyes e s upon he inco po a ion o cyclic ace alized galac a ic uni s. Glass- ansi ion and mel ing empe a u es, and mel ing en halpies measu ed in he DSC analysis o bo h p is ine samples and samples c ys allized om he mel a e gi en in Table 3.6. A ema kable ea u e o Galx homopolyes e s is ha hey ha e conside ably highe Tg han hei analogues made o Ad. Acco dingly, he Tg o he copolyes e s wi hin each se ies inc eases s eadily wi h he con en in Galx uni s wi h minimum and maximum alues co esponding o hei espec i e e e ence homopolyes e s (Figu e 3.16). The end obse ed o Tg wi h he copolyes e composi ion is in ull ag eemen wi h wha should be expec ed om he s i ness/bulkiness o he bicyclic suga uni compa ed o he ela i e lexible/slende e ame hylene segmen o he adipic acid, once i is p o ided ha he mic os uc u e o he copolyes e s is s a is ical. Figu e 3.16. Glass- ansi ion empe a u e (a) and mel ing empe a u e (b) s. composi ion plo s o PE-12AdxGalxy and PE-6AdxGalxy. Chap e 3 108 3.3.3.3. C ys al s uc u e I is known ha he inse ion o suga uni s bea ing side g oups in linea polyamides and polyes e s c ea e bulky he e ogenei ies in he polyme hinde ing he close chain packing equi ed o c ys alliza ion. The beha io usually obse ed is ha bo h alipha ic and a oma ic andom copolyes e s wi h mino amoun s o suga uni s, i.e. below ~30%, a e able o c ys allize e aining he c ys al s uc u e o he pa en homopolyes e wi h ejec ion o he suga uni s om he c ys alline phase. Whe eas homopolyes e s en i ely made o suga uni s a e able o c ys allize adop ing speci ic c ys al s uc u es, he copolyes e s en iched in suga uni s a e usually amo phous (Zamo a e al., 2005; Alla e al., 2006 and 2008). DSC has shown ha bo h PE- 12AdxGalxy and PE-6AdxGalxy copolyes e s a e c ys alline o he whole ange o composi ions which is a a he unusual beha io . The X- ay di ac ion analysis co obo a ed he DSC esul s since, as i is shown in Figu e 3.22, disc e e sca e ing p o iles indica i e o semic ys alline ma e ial we e eco ded o he whole se ies. The B agg spacings and c ys allini y indexes measu ed on such p o iles a e compa ed in Table 3.8. I is seen ha homopolyme PE-12Ad and he copolyme s PE-12Ad90Galx10 and PE-12Ad70Galx30 display he same di ac ion pa e n which is dis inguished by he p esence o wo p ominen e lec ions a 4.2 and 3.7 Å. Such a pa e n is cha ac e is ic o poly(alkylene dica boxyla e) polyes e s which a e known o c ys allize usually in an o ho hombic o monoclinic la ice wi h chains adop ing a quasi all- ans con o ma ion (A melin e al., 2001). Acco dingly, he wo obse ed e lec ions should be ela ed wi h he side-by-side packing o he chains and indexed he e o e as hk0, and he absence o highe spacing e lec ions, which would a ise om planes wi h l  0, may be in e p e ed as he esul o he balancing shi o he chains along he c di ec ion o he s uc u e. A di e en pa e n con aining h ee sha p e lec ions a 4.0, 4.3 and 4.6 Å along wi h ano he b oad one a 17-18 Å was eco ded o PE-12AdxGalxy copolyes e s wi h 50% o mo e o Galx uni s as well as o he homopolyes e PE-12Galx. I is clea ha a new c ys al s uc u e is adop ed when he con en in Galx uni s becomes he majo i y. The X- ay di ac ion pa e n shown in Figu e 3.22, which is illus a i e o he whole se , was eco ded om a ibe o PE-12Ad10Galx90 ob ained by s e ching om he mel . The e lec ions a 4.0 and 4.6 Å a e equa o ially placed and in e p e ed he e o e o a ise om hk0 plane whe eas he in-be ween one a 4.3 Å is o -me idional and should be ela ed wi h he azimu hal a angemen o he chains. On he o he hand, he e lec ion a 17.9 Å is obse ed in he ibe pa e n a an o -me idian posi ion (inse o Figu e 3.22b). This Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 109 e lec ion may be indexed as ei he hk0 o hk1 o a c ys al s uc u e made o almos ex ended chains which a e p og essi ely o egula ly shi ed along he c-axis, espec i ely. Since he epea ing uni leng h calcula ed o PE-12AdxGalxy wi h he chain in all- ans con o ma ion is 24 Å, i is concluded ha he shi ing o he chains mus be a ound 3 Å. Figu e 3.22. a) Powde WAXD p o iles o PE-12AdxGalxy copolyes e s. b) Fibe pa e n o PE- 12Ad10Galx90 ( ibe axis e ical), Inse : Inne egion showing medium-angle e lec ions. Chap e 3 110 Table 3.8. Powde X- ay di ac ion da a and mechanical p ope ies o PE-12AdxGalxy copolyes e s. Copolyes e X- ay di ac ion da a Mechanical P ope ies d a (Å) Xcb Elas ic modulus Tensile s eng h Elonga ion a b eak (MPa) (MPa) (%) PE-12Ad 4.2 s 3.7 m 0.51 87 ± 5 6 ± 1 215 ± 9 PE-12Ad90Galx10 4.2 s 3.7 m 0.48 98 ± 4 7 ± 1 110 ± 8 PE-12Ad70Galx30 4.2 s 3.7 m 0.47 100 ± 4 8 ± 1 92 ± 7 PE-12Ad50Galx50 17.9 s 4.6 s 4.3 s 4.0 s 0.46 107 ± 3 9 ± 1 90 ± 8 PE-12Ad30Galx70 17.9 s 4.6 s 4.3 s 4.0 s 0.44 129 ± 5 10 ± 1 78 ± 8 PE-12Ad10Galx90 17.9 s 4.6 s 4.3 s 4.0 s 0.43 140 ± 5 12 ± 1 67 ± 6 PE-12Galx 17.9 s 4.6 s 4.3 s 4.0 s 0.42 155 ± 4 13 ± 1 59 ± 4 a B agg spacings measu ed in powde di ac ion pa e ns o samples coming di ec ly om syn hesis. In ensi ies isually es ima ed as ollows: m, medium; s, s ong; w, weak. b C ys allini y index calcula ed as he quo ien be ween c ys alline a ea and o al a ea. C ys alline and amo phous a eas we e quan i ied using PeakFi 4.12 so wa e. 3.3.3.4. S ess-s ain beha io Alipha ic polyes e s a e known o display meage mechanical p ope ies, which oge he wi h hei a he low mel ing empe a u e, cons i u e one o he main easons ha ha e hampe ed hei indus ial expansibili y. This has also es ic ed hei use in biomedical applica ions in spi e o hei good biocompa ibili y and biodeg adabili y. In his ega d i is in e es ing o e alua e he e ec o he eplacemen o he alkylene dica boxyla e by he galac a a e uni s on he mechanical beha io o polyadipa es. Fo his aim, compa a i e ensile essays o he PE-12AdxGalxy se ies we e ca ied ou using hin ilms p epa ed by cas ing om chlo o o m solu ion. The aces egis e ed in hese essays a e shown in Figu e 3.23 and he mechanical pa ame e s alues ex ac ed om such aces a e gi en in Table 3.8. The e olu ion ollowed by he s ess-s ain cu es wi h he con en in Galx uni s clea ly illus a es hei in luence on he mechanical compliance. I is no ewo hy how he beha io changes om lexible/duc ile ypical o semic ys alline alipha ic polyes e s o s i /b i le when adipa e uni s a e en i ely eplaced by Galx uni s; he elas ic modulus becomes almos doubled and he elonga ion o b eak is educed o nea one ou h o i s alue. The copolyes e s wi h in e media e composi ions show a s eadily changing s ess-s ain beha io wi h mechanical pa ame e s spanning be ween hose o he wo homopolyes e s. As expec ed, he obse ed changes in he s ess-s ain beha io closely ollow he changes in Tg; bo h e ec s a e he logical consequence o he Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 111 inc easing s i ness o he polyes e chain ha is mo i a ed by he p og essi e eplacemen o Ad by Galx. Figu e 3.23. S ess-s ain cu es o PE-12AdxGalxy copolyes e s. 3.3.4. Conclusions The bicyclic dies e dime hyl 2,3:4,5-di-O-me hylene galac a a e (Galx) was success ully copolyme ized in he mel wi h dime hyl adipa e and alkanediols (1,6- hexanediol and 1,12-dodecanediol) o ob ain bio-based polycyclic andom copolyes e s co e ing he ull ange o composi ions. The Galx con aining copolyes e s had ag eeable molecula weigh s and we e he mally s able and semic ys alline o all composi ions. The en iched adipa e copolyes e s ake up he c ys al s uc u e ypical o alipha ic linea polyes e s while a second c ys al o m seems o be adop ed o high con en s in suga uni s. The mel ing empe a u e o he copolyes e s changes wi h composi ion acco ding o a powe unc ion ha goes o he minimum as he con en s in he wo comonome s app oach o each o he . Copolyes e s made om 1,12-dodecanediol we e able o c ys allize om he mel a a a e depending on composi ion. The inco po a ion o he Galx uni in he polyadipa e chain inc eased he Tg as well as he modulus o igidi y and he s ess yield whe eas diminished he duc ili y o he polyme . The sui abili y o he bicyclic ace alized dime hyl galac a a e o p epa e bio-based alipha ic copolyes e s wi h o e all sa is ying p ope ies and inc eased Tg has been demons a ed. Chap e 3 112 3.3.5. Re e ences Alla, A.; Hakkou, K.; Zamo a, F.; Ma ínez de Ila duya, A.; Galbis, J.A.; Muñoz-Gue a, S., Mac omolecules 2006, 39, 1410-1416. Alla, A.; Hakkou, K.; Zamo a, F.; Ma ínez de Ila duya, A.; Galbis, J.A.; Muñoz-Gue a, S., J Polym. Sci., Polym. Chem. 2008, 46, 5167–5179. A melin, E.; Casas, M.T.; Puiggalí, J. Polyme 2001, 42, 5695-5699. 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Ca bohyd. Chem. Biochem. 2000, 55, 137-174. Va ma, A.J.; Kennedy, J.F.; Galgali, P.Q. Ca bohyd. Polym. 2004, 56, 429-445. Wool, R.; Sun, S. Biobased Polyme s and Composi es; Academic P ess: New Yo k, 2005. Zamo a, F.; Hakkou, K.; Alla, A., Espa e o, J.L.; Muñoz-Gue a, S.; Galbis, J.A. J. Polym. Sci., Polym. Chem. 2005, 43, 6394–6410. Chap e 3 114 Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 115 3.4. High Tg bio-based alipha ic polyes e s om bicyclic D-manni ol Summa y: The ca bohyd a e-based diol 2,4:3,5-di-O-me hylene-D-manni ol (Manx) has been used o ob ain alipha ic polyes e s. Manx is a symme ic bicyclic compound consis ing o wo used 1,3-dioxane ings and bea ing wo p ima y hyd oxyl g oups. In e ms o s i ness i is compa able o he widely known isoso bide bu i a o ds he addi ional ad an ages o being much mo e eac i e in polycondensa ion and capable o p oducing s e eo egula polyme s wi h ai ly high molecula weigh s. A ully bio-based homopolyes e (PManxS) has been syn hesized by polycondensa ion in he mel om dime hyl succina e and Manx. The high he mal s abili y o PManxS, i s ela i ely high glass- ansi ion empe a u e (Tg= 68 ºC) and elas ic modulus, and i s enhanced sensi i i y o he ac ion o lipases poin o PManxS as a polyes e o excep ional in e es o hose applica ions whe e biodeg adabili y and molecula s i ness a e p io i y equi emen s. In addi ion, andom copolyes e s (PBxManxyS) co e ing a b oad ange o composi ions ha e been ob ained using mix u es o Manx and 1,4-bu anediol in he eac ion wi h dime hyl succina e. All PBxManxyS we e semic ys alline and displayed Tg alues om -29 o +51 ºC s eadily inc easing wi h he con en in Manx uni s. The s ess-s ain beha io o hese copolyes e s la gely depended on hei con en in Manx and hey we e enzyma ically deg aded as e han PBS. Publica ion de i ed om his wo k: La illa, C.; Alla, A.; Ma ínez de Ila duya, A.; Muñoz-Gue a, S. Biomac omolecules 2013, 14, 781-793. Chap e 3 116 3.4.1. In oduc ion Due o inc easing conce ns on sus ainable de elopmen and minimizing he impac o ma e ials on he en i onmen , biodeg adable polyme s ha e a ac ed a g ea deal o in e es in he las decades (Engelbe g and Kohn, 1991; Albe sson and Va ma, 2002; Okada, 2002; Nai and Lau encin, 2007). Alipha ic polyes e s such as poly(bu ylene succina e) (PBS), poly(L-lac ic acid), poly(ε-cap olac one) and poly(3- hyd oxy bu y a e) among o he s, cons i u e a dis inguished bunch o biodeg adable polyme s ha a e comme cially a ailable in se e al o ms. Some o hese alipha ic polyes e s ha e ound in ensi e use in a b oad a ie y o medical applica ions such as bio eso bable su gical su u es, p os hesis, den al implan s, bone sc ew and pla es o empo a y in e nal ac u e ixa ion, and con olled d ug deli e y sys ems (Wang e al., 2012; Cou inho e al., 2012). Nowadays PBS is ecei ing excep ional a en ion as a polyme ic ma e ial sui able o eplacing con en ional commodi y plas ics in injec ion- molded a icles (cu le y, b ushes), ubula ilms (compos ing bags, shopping bags), lexible packaging and ood ay since i has a mel ing empe a u e simila o ha o low densi y polye hylene, sa is ac o y mechanical p ope ies and can be p ocessed wi h he con en ional equipmen s commonly used o polyole ins (Papageo giou and Bikia is, 2007; Gualandi e al., 2012). Howe e , PBS has a glass- ansi ion empe a u e (Tg) o -37 ºC, no high enough o i s use in igid packaging and cosme ic and be e age bo les whe e s i ness and he mal esis ance a e p io i y equisi es. In his ega d, a ious app oaches such as blending and copolyme iza ion wi h a oma ic polyes e s as poly(bu ylene e eph hala e) (PBT) and poly(e hylene e eph hala e) (PET) ha e been ecen ly explo ed (Deng e al., 2004; Li e al., 2012). The in e es o cyclic monome s a ises om hei capaci y o adding s i ness o he polyme chain wi h he subsequen inc ease in Tg; he disad an age o using a oma ic uni s o such pu pose is ha hey a e o igina ed om ossil eeds ocks and a e eluc an o biodeg ada ion. The use o ca bohyd a e-based monome s wi h a cyclic s uc u e cons i u e a sca cely explo ed app oach o he p epa a ion o enewable alipha ic polyes e s wi h imp o ed physical p ope ies, especially hose ela ed o polyme chain s i ness (Galbis and Ga cía-Ma ín, 2010; Gandini, 2011). Mo eo e , ca bohyd a e-de i ed polycondensa es ypically display enhanced hyd ophylici y, lowe oxici y and highe suscep ibili y o hyd oly ic deg ada ion and biodeg ada ion han hose coming om pe ochemical eeds ocks. Thus 2,3-O-isop opylidene-L- a a ic acid (Dhamaniya and Jacob, 2010 and 2012) and 2,5- u andica boxylic acid (Gandini e al., 2009; Gomes e al., Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 117 2011; Wu e al., 2012a) ha e been polyme ized wi h se e al diols o ob ain bio-based alipha ic cyclic polyes e s. 1,4:3,6-Dianhyd o-D-gluci ol, known as isoso bide, which is p epa ed by dehyd a ion o D-glucose coming om ce eal s a ch, is he only bicyclic ca bohyd a e-based monome indus ially a ailable oday. Isoso bide, along wi h hei wo less accessible s e eoisome s isomannide and isoidide, a e cu en ly d awing an eno mous in e es in he polyme science ield as bio-based monome s able o p o ide enhanced s i ness in o he polyme chain hey a e inco po a ed (Fenouillo e al., 2010). These h ee isohexides a e composed o wo used e ahyd o u an ings, wi h wo seconda y hyd oxyl g oups emaining ee o eac ion. Due o hei used bicyclic s uc u e, 1,4:3,6-dianhyd ohexi ols and hei diacid de i a i es a e able o inc ease he glass- ansi ion empe a u e o common alipha ic polyes e s (B aun and Be gmann, 1992; Okada e al., 1996 and 2000; Noo do e e al., 2006; Wu e al., 2012b). Ne e heless, he main sho coming o isoso bide and i s isome s is he limi ed eac i i y o hei seconda y hyd oxyl g oups; in ac , his ea u e se iously hampe s he polycondensa ion eac ion in he mel , so alipha ic polyes e s om 1,4:3,6-dianhyd ohexi ols and alipha ic dica boxylic acids o dica boxylic es e s ob ained by his me hod display a he limi ed molecula weigh s (B aun and Be gmann, 1992; Noo do e e al., 2006). Highe molecula weigh s a e achie able ia polycondensa ion wi h alipha ic dica boxylic chlo ides (Okada e al., 1996 and 2000), bu his me hod is no app op ia e o indus ial applica ion (F ade and Tessie , 2003). Recen ly, we ha e epo ed he syn hesis and cha ac e iza ion o alipha ic polyes e s made om dime hyl 2,3:4,5-di-O-me hylene-galac a a e (Galx), which is a bicyclic monome ob ained by in e nal ace aliza ion o galac a ic acid (La illa e al., 2011 -Subchap e 3.2- and 2012a -Subchap e 3.3-). This monome has been shown o be e y sui able o p epa e alipha ic polyes e s by polycondensa ion wi h alipha ic diols in he mel , since i is able o eac a a a e simila o ha o o he acyclic con en ional monome s. A di e ence wi h dianhyd ohexi ols, Galx is composed o wo independen 1,3-dioxolane ings linked by a single C-C bond, and hence hey we e ound o con e lowe igidi y o he polyes e backbone han a used bicyclic s uc u e is able o do. To ou knowledge, he bicyclic dies e Galx is he only bicyclic diace alized ca bohyd a e- based monome ha has been used up o da e o ob ain alipha ic polyes e s. In his wo k bicyclic 2,4:3:5-di-O-me hylene-D-manni ol, abb e ia ed as Manx, has been used o ob ain alipha ic polyes e s. Manx is ob ained by in e nal ace aliza ion o D-manni ol in a simila way o he bicyclic dies e Galx is ob ained om mucic acid. Chap e 3 124 Table 3.9. Mola composi ion, molecula weigh , mic os uc u e and con ac angle. Copolyes e Mola composi ion Molecula weigh Mic os uc u e Con ac anglee Yield (%) Feed Copolyes e a Dyads Numbe A e age Sequence Leng hs Randomnessd XB XManx XB XManx [η]b Mnc Mwc Ðc BB BManx/ ManxB Manx Manx nB nManx R θwa e (deg) PBS 90 100 0 100 0 0.97 19,500 49,100 2.5 113±4 PB95Manx5S 87 95 5 94.3 5.7 0.90 19,900 47,800 2.4 87.9 11.4 0.7 16.4 1.1 0.96 114±5 PB90Manx10S 89 90 10 88.7 11.3 0.72 16,900 39,100 2.3 78.0 20.5 1.5 8.6 1.1 0.99 114±4 PB80Manx20S 88 80 20 80.7 19.3 0.69 14,600 35,200 2.4 66.3 30.8 3.0 5.3 1.2 1.03 117±3 PB70Manx30S 86 70 30 69.1 30.9 0.70 14,200 35,000 2.5 47.0 44.3 8.8 3.1 1.4 1.04 113±2 PB50Manx50S 87 50 50 51.1 48.9 0.61 13,900 33,400 2.4 26.1 50.0 24.0 2.0 2.0 1.00 114±4 PB30Manx70S 89 30 70 29.7 70.3 0.60 13,500 33,500 2.5 8.4 43.4 48.2 1.4 3.2 1.03 116±8 PManxS 85 0 100 0 100 0.56 13,300 30,800 2.3 74±7 a a Mola composi ion de e mined by in eg a ion o he 1H NMR spec a. b In insic iscosi y in dL·g-1 measu ed in chlo o o m a 25 ºC. c Numbe and weigh - a e age molecula weigh s in g·mol-1 and dispe si ies measu ed by GPC in HFIP agains PMMA s anda ds. d Randomness index o copolyes e s s a is ically calcula ed on he basis o he 13C NMR analysis. e Con ac angle measu ed a e 45 seconds o d opping 1.5 µL o wa e . Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 125 Bo h he 1H and 13C NMR analysis asce ained he chemical cons i u ion and composi ion o he polyes e s. They a e de ailed in Sec ion 3.4.2, and a selec ion o he illus a i e spec a is p o ided in Annex C. The assignmen o he signals a ising om he suga uni s was suppo ed by COSY and HETCOR spec a, which a e included in Annex C. In eg a ion o he p o on signals a ising om B and Manx uni s led o quan i y he composi ion o he copolyes e s in such uni s, which appea ed o be e y close o hose o hei espec i e eeds (Table 3.9). The mic os uc u e o PBxManxyS copolyes e s was de e mined by 13C NMR analysis. As i is depic ed in Figu e 3.24, he 13C NMR spec a o copolyes e s show one o he succinic signals wi h esolu ion enough as o make possible he elucida ion o he copolyes e mic os uc u e as a as dis ibu ion o B and Manx uni s along he copolyes e chain is conce ned. As a consequence o he occu ence o di e en dyad ypes (BB, BManx, ManxB and ManxManx), his signal appea s spli in o ou peaks ha sp ead wi hin he 29.2-29.7 ppm chemical shi in e al. By in eg a ion o hese peaks, he dyad con en s, he numbe -a e age sequence leng hs and he deg ee o andomness we e es ima ed (Table 3.9), leading o he conclusion ha he mic os uc u e o he copolyes e s was andom in all cases. Figu e 3.24. 13C NMR signals used o he mic os uc u e analysis o PBxManxyS copolyes e s wi h indica ion o he dyads o which hey a e assigned. Chap e 3 126 The sol en a ini y o Manx con aining polysuccina es was simila o ha displayed by PBS. All hey con inue o be non-soluble in wa e bu eadily soluble in chlo o o m. The con ac angle be ween wa e and polyes e ilms was measu ed o es ima e hei hyd ophilici y (Table 3.9); no signi ican di e ences we e obse ed in he θwa e o PBS (~113º) wi h he inco po a ion o Manx uni s excep o he case o he homopolyes e whe e he con ac angle dec eased o nea 75º indica ing he much highe hyd ophilic cha ac e o his compound. 3.4.3.2. The mal and mechanical p ope ies The he mal beha io o PManxS homopolyes e and PBxManxyS copolyes e s has been compa a i ely s udied by TGA and DSC; he he mal pa ame e s esul ing om hese analyses a e gi en in Table 3.10, whe e he co esponding da a o he homopolyes e PBS a e also included o e e ence. Fi s , he he mal s abili y was e alua ed by TGA unde ine a mosphe e. The TGA aces o PManxS and PBS homopolyes e s oge he wi h hei de i a i e cu es a e shown in Figu e 3.25a, and hose eco ded om he whole se o PBxManxyS copolyes e s a e compa a i ely depic ed in Figu e 3.25b. The mal decomposi ion o PManxS occu s in a single s age wi h maximum a e aking place a 413 ºC (maxTd), and only 5% o he ini ial weigh emains a 600 ºC; he maximum decomposi ion a e o PBS homopolyes e occu s a 384 ºC (maxTd), he esidual weigh le upon hea ing a 600 ºC being 4%. Decomposi ion o PBxManxyS copolyes e s akes place also in one s age, a empe a u es anging be ween maxTd o hei wo co esponding homopolyes e s PBS and PManxS and s eadily inc easing as bu anediol uni s a e eplaced by Manx uni s. The aluable conclusion d awn om his compa a i e he mog a ime ic s udy is ha he inse ion o Manx in alipha ic polyes e s ins ead o educing hei decomposi ion empe a u es con ibu es signi ican ly o inc easing hei he mal s abili y, which can b oaden e en mo e he applica ion window o alipha ic polyes e s. Since he mel ing in hese copolyes e s dec eases wi h composi ion, a wide ange o empe a u es be ween mel ing and decomposi ion exis s, allowing a mo e com o able mel p ocessing. Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 127 Table 3.10. The mal p ope ies. Copolyes e TGA DSC Fi s hea inge Coolinge Second hea inge ºT5%a Tdb W c Tgd Tm ΔHm Tc ΔHc Tc ΔHc Tm ΔHm (ºC) (ºC) (%) (ºC) (ºC) (J·g-1) (ºC) (J·g-1) (ºC) (J·g-1) (ºC) (J·g-1) PBS 320 384 4 -37 111/114 (113) 75.0 (103.1) 81 60.7 - - 113 61.1 PB95Manx5S 320 386 6 -29 107 (107) 62.9 (69.3) 64 59.5 - - 107 60.7 PB90Manx10S 322 387 5 -20 94 (93) 45.3 (48.4) 42 16.9 35 18.7 95 36.2 PB80Manx20S 323 410 4 -8 50/74/84 (51/82) 44.7 (47.3) - - 59 16.0 85 16.1 PB70Manx30S 322 413 4 3 52/64 (49/63) 30.1 (38.7) - - - - - - PB50Manx50S 323 413 4 26 64/85 (62/80) 10.1 (10.9) - - - - - - PB30Manx70S 321 413 5 51 91 (90) 3.8 (4.6) - - - - - - PManxS 320 413 5 68 - (125) - (14.0) - - - - - - aTempe a u e a which 5% weigh loss was obse ed. bTempe a u e o maximum deg ada ion a e. cRemaining weigh a 600 ºC. dGlass- ansi ion empe a u e aken as he in lec ion poin o he hea ing DSC aces o mel -quenched samples eco ded a 20 ºC·min-1. eMel ing (Tm) and c ys alliza ion (Tc) empe a u es, and mel ing (ΔHm) and c ys alliza ion (ΔHc) en halpies measu ed by DSC a hea ing/cooling a es o 10 ºC·min-1 o powde ed samples coming di ec ly om syn hesis (wi hou pa en heses) and o ilms p epa ed by cas ing om solu ion (in pa en heses). A e annealing o 1h a 60 ºC, Tm inc eased o 127 ºC and ΔHm o 21.5 J·g-1. Chap e 3 128 Figu e 3.25. (a) TGA aces (solid lines) and de i a i e cu es (dashed lines) o PBS and PManxS homopolyes e s. (b) TGA aces o PBxManxyS copolyes e s. Ano he he mal p ope y o p ime impo ance in connec ion wi h he po en ial applica ion o hese polyes e s is he glass- ansi ion empe a u e (Tg). Fo ins ance, an inc ease in he Tg o alipha ic polyes e s such as PBS could open hei use in he igid packaging ield. The DSC analyses e ealed ha he Tg s eadily inc eased as bu anediol was eplaced by Manx uni s going om -29 ºC o PB95Manx5S up o 51 ºC o PB30Manx70S (Figu e 3.26a). These esul s a e ully consis en wi h he Tg alues o -37 ºC and 68 ºC obse ed o he PBS and PManxS homopolyes e s, espec i ely, p o ided ha he mic os uc u e o he copolyes e s is andom. Such a ema kable posi i e e ec o he inco po a ion o Manx on Tg makes his compound a bio-based comonome e y sui able o he p epa a ion o alipha ic polyes e s wi h enhanced Tg. Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 129 Figu e 3.26. (a) DSC hea ing aces o PBxManxyS copolyes e s quenched om he mel . (b) DSC hea ing aces o PBxManxyS copolyes e s coming di ec ly om syn hesis. DSC aces o polyes e s coming di ec ly om syn hesis a e depic ed in Figu e 3.26b. All PBxManxyS copolyes e s as well as PBS homopolyes e ga e hea ing aces wi h mel ing endo he ms indica ing ha hey we e semic ys alline, whe eas PManxS appea ed o be amo phous. Compa ison o mel ing empe a u es and en halpies o PBxManxyS copolyes e s wi h ha o PBS leads o he conclusion ha he inse ion o Manx uni s gi es place o a signi ican dec ease in bo h Tm and ΔHm. The Tm did no ollow a con inuous end wi h composi ion bu i ell in o a minimum o copolyes e composi ions a ound 30% o Manx uni s (Figu e 3.27). This beha io sugges ed he occu ence o wo di e en c ys al s uc u es depending on he uni , bu anediol o Manx, ha is p edominan in he copolyes e . To complemen DSC da a, powde X- ay di ac ion analyses we e pe o med o PBxManxyS copolyes e s as well as o PBS and PManxS homopolyes e s coming di ec ly Chap e 3 130 om syn hesis. The X- ay di ac ion p o iles eco ded om powde s a e compa ed in Figu e 3.28, and he mos p ominen B agg spacings p esen he ein a e lis ed in Table 3.11. Essen ially he same di ac ion pa e n ega ding bo h spacing and in ensi ies is sha ed by PBS homopolyes e and copolyes e s con aining up o 30% o Manx uni s. This pa e n is dis inguished by he p esence o h ee sha p s ong e lec ions a 4.5, 4.1 and 3.9 Å indica ing ha he monoclinic c ys al s uc u e o PBS (Ihn e al., 1995) is e ained in such copolyes e s. I mus be assumed ha he bicyclic s uc u e in hese copolyes e s is seg ega ed om he c ys al la ice which is made o homogeneous sequences o bu ylene succina e uni s. Since he a e age leng h o hese sequences diminishes wi h he con en in Manx, he c ys alli e hickness dec eases and consequen ly Tm goes down. Con e sely, bo h PB50Manx50S and PB30Manx70S p oduced a sca e ing p o ile wi h a clea ly di e en shape whe e he h ee mos p ominen e lec ions co esponding now o 4.7, 4.5 and 4.0 Å which also coincides wi h ha exhibi ed by he PManxS homopolyes e . The la ge alues obse ed o hese spacings, which p esumably a ise om he in e plana dis ances ha a e de ined by he side-by-side packing o he chains, a e consis en wi h he bigge size o Manx compa ed o bu anediol. In addi ion, se e al weake e lec ions a e obse ed a highe spacings in he 6-8 Å ange, which migh be associa ed o he axial epea o he polyes e chain. Appa en ly a second c ys al o m di e en om ha o PBS, which is able o accommoda e he bicyclic s uc u e in he la ice, seems o be adop ed by bo h he homopolyes e and he copolyes e s con aining majo amoun s o Manx. In his case he bu ylene succina e would be he uni ha is seg ega ed om he c ys alline phase; acco dingly, he Tm in he Manx-en iched in e al should be expec ed o inc ease wi h he con en in Manx, as i is expe imen ally obse ed. Figu e 3.27. Glass- ansi ion and mel ing empe a u es e sus composi ion plo o PBxManxyS copolyes e s. Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 131 Table 3.11. Powde X- ay di ac ion da a and mechanical p ope ies. Copolyes e X- ay di ac ion da a Mechanical P ope ies d a (Å) Xcb Elas ic modulus Tensile s eng h Elonga ion a b eak (MPa) (MPa) (%) PBS 4.5 m 4.1 m 3.9 s 3.4 w 3.1 w 2.6 w 0.52 351±11 20±2 19±4 PB95Manx5S 4.5 m 4.1 m 3.9 s 3.4 w 3.1 w 2.6 w 0.48 355±13 22±2 14±3 PB90Manx10S 4.5 m 4.1 m 3.9 s 3.4 w 3.1 w 2.6 w 0.45 372±14 22±2 9±2 PB80Manx20S 4.5 m 4.1 m 3.9 s 3.4 w 3.1 w 2.6 w 0.43 403±15 24±2 7±3 PB70Manx30S 4.5 m 4.1 m 3.9 s 3.4 w 3.1 w 2.6 w 0.37 428±12 24±3 5±2 PB50Manx50S 7.0 w 6.2 w 5.6 w 4.7 s 4.5 m 4.2 w 4.0 m 3.4 w 3.1 w 2.9 w 2.8 w 0.28 471±15 26±2 3±1 PB30Manx70S 7.0 w 6.2 w 5.6 w 4.7 s 4.5 m 4.2 w 4.0 m 3.4 w 3.1 w 2.9 w 2.8 w 0.17 515±14 28±3 2±1 PManxS (7.0 w) (6.2 w) (5.6 w) (4.7 s) (4.5 m) (4.2 w) (4.0 m) (3.4 w) (3.1 w) (2.9 w) (2.8 w) (0.31) 573±15 31±3 2±1 a B agg spacings measu ed in powde di ac ion pa e ns. In ensi ies isually es ima ed as ollows: m, medium; s, s ong; w, weak. Da a om samples coming di ec ly om syn hesis (wi hou pa en heses) and om PManxS ilm annealed o 1h a 60 ºC (in pa en heses). b C ys allini y index calcula ed as he quo ien be ween c ys alline a ea and o al a ea quan i ied in he X- ay di ac ion p o iles using he PeakFi 4.12 so wa e. Chap e 3 132 Figu e 3.28. Powde WAXD p o iles o PBS, PManxS and PBxManxyS copolyes e s coming di ec ly om syn hesis. *The PManxS p o ile a he bo om was ob ained om a ilm cas ed om chlo o o m ha was annealed o 1 h a 60 ºC. C ys allini y was ound howe e o decay s eadily along he whole se ies as he con en in Manx uni s inc eased, o he poin ha no disc e e sca e ing could be de ec ed o he homopolyes e PManxS coming di ec ly om syn hesis. These obse a ions a e in ull ag eemen wi h DSC esul s and e eal he dep essing in luence ha he bicyclic s uc u e has on c ys allizabili y, which may be due o he opposi e e ec ha i has on Tm and Tg. Inc easing amoun s o Manx led o polyes e s wi h na owe c ys alliza ion window (Tm-Tg) and he e o e exhibi ing less c ys allini y because he mel becomes ozen be o e he chains can c ys allize upon supe cooling. Ne e heless, PManxS was able o c ys allize by cas ing om a chlo o o m solu ion. A e annealing he cas ilm showed a mel ing peak a 127 ºC wi h an en halpy o 21.5 J·g-1, and p oduced a WAXD p o ile iden ical o hose eco ded om he en iched Manx copolyes e s (Figu e 3.28). These esul s sugges ha a he han hampe ing he close side-by-side packing o he polyes e chains equi ed o o m he c ys al la ice, he main ep essing e ec o Manx on c ys alliza ion should be due o he es ic ed mobili y ha he p esence o he bicyclic s uc u e con e s o he polyes e chain. This is in ull ag eemen wi h he high delay ha is obse ed in he iso he mal c ys alliza ion ime o PBxManxyS o sligh ises in Manx con en s, mo e han en old o a 5% o inc emen in Manx (see below). Alipha ic polyes e s om cyclic ace alized ca bohyd a e-based monome s 133 Figu e 3.29. Iso he mal c ys alliza ion o PBS, PB95Manx5S and PB90Manx10S a he indica ed empe a u es. Rela i e c ys allini y e sus ime plo (a) and log-log plo (b). The cooling DSC aces ob ained om mol en samples e ealed ha PBxManxyS copolyes e s wi h mola con en s in Manx below o equal o 10%, as well as PBS homopolyes e , we e able o c ys allize om he mel . A e c ys alliza ion upon cooling a a cons an a e o 10 ºC·min-1, PBS homopolyes e and PB95Manx5S copolyes e eco e ed abou 80-97% o hei ini ial c ys allini y and displayed almos he same mel ing empe a u es. Con e sely PB90Manx10S copolyes e c ys allized unde such condi ions eco e ing only 37% o i s o iginal c ys allini y. Howe e , i p esen ed cold c ys alliza ion a he second hea ing un wi h eco e ing abou 80% o he ini ially c ys allized ma e ial, and mel ing a nea ly he same ini ial empe a u e. Gi en he ele ance o he abili y o c ys allizing om he mel ega ding polyme p ocessing, he iso he mal c ys alliza ion o PB95Manx5S and PB90Manx10S copolyes e s and PBS homopolyes e was compa a i ely s udied in he 70-100 ºC in e al. Un o una ely, no all o hem could be compa ed a exac ly he same c ys alliza ion empe a u e due o la ge di e ences in c ys alliza ion a es displayed by hem; ne e heless, c ys alliza ion condi ions we e chosen as close as possible in o de o be able o d aw ou meaning ul conclusions. A ami log[-ln(1-Xc)] e sus log( - 0) da a plo s and he e olu ion o he ela i e c ys allini y, Xc, e sus Chap e 5 236 Figu e 5.19. Compa ed 1H NMR a e incuba ion wi h wa e a pH 2.0 a 80 ºC and ini ial spec a o PB50Galx50T (a) and PBT50Galx50 (b) copolyes e s, and ep esen a ion o Galx con en s. incuba ion ime. SEM analysis e ealed ha upon incuba ion PBT sphe uli es showed c acks in a low p opo ion whe eas sphe uli es o incuba ed PGalxT homopolyes e appea ed equen ly c acked (Annex E); wi h ega d o PB50Galx50T copolyes e , he ini ial su ace displayed also e y appa en physical al e a ions (Figu e 5.17), showing ha hyd oly ic deg ada ion was la gely enhanced by he p esence o galac i ol uni s. Bo h sample weigh ing and SEM obse a ions indica ed ha PB50Galx50T copolyes e became Poly(bu ylene e eph hala e) copolyes e s om cyclic ace alized ca bohyd a e-based monome s 237 appa en ly deg aded in a highe deg ee han PGalxT homopolyes e despi e i s lesse con en in galac i ol. The eason o such beha io may be he lowe glass- ansi ion empe a u e displayed by he copolyes e . 5.3.3.2. PBT copolyes e s con aining galac a a e uni s To in es iga e he in luence o he inco po a ion o dime hyl 2,3:4,5-di-O- me hylene-galac a a e on deg ada ion o PBT, a compa a i e s udy o he wo homopolyes e s PBT and PBGalx and he in e media e PBT50Galx50 copolyes e was ca ied ou unde he same condi ions used in he s udy o he PBT copolyes e s con aining galac i ol uni s desc ibed abo e. 5.3.3.2.1. Hyd oly ic deg ada ion and biodeg ada ion a pH 7.4 a 37 ºC The changes aking place in sample weigh and molecula weigh o PBT, PBT50Galx50 and PBGalx polyes e s a inc easing incuba ion imes in aqueous pH 7.4 bu e a 37 ºC, wi h and wi hou po cine panc eas lipase, a e p esen ed in Figu e 5.20. The weigh ha was los upon 8 weeks o incuba ion in he p esence o lipase was abou 20% and 35% o PBT50Galx50 and PBGalx, espec i ely; whe eas only 5% and 7% was los upon incuba ion o he same polyes e s in he absence o enzymes, espec i ely. Howe e , he sample weigh and molecula weigh o PBT homopolyes e was main ained unchangeable h ough he whole p ocess. On he con a y, a sligh decay in Mw and Mn was obse ed o bo h PBT50Galx50 and PBGalx polyes e s when incuba ed in he absence o enzymes. Fu he mo e, when hese wo polyes e s we e incuba ed wi h lipase, Mw and Mn decayed subs an ially, he mo e p onounced change being obse ed o he homopolyes e in ag eemen wi h he expec ed abili y o galac a a e uni s o making PBT biodeg adable. Mel ing en halpies o PBT samples upon incuba ion we e nea ly he same han ha o he ini ial sample acco ding o he inexis ence o deg ada ion. Howe e , i was no ewo hy o obse e ha he c ys allini y o bo h PBT50Galx50 and PBGalx inc eased as deg ada ion p oceeded, and ha he aise in c ys allini y was highe when samples we e incuba ed in he p esence o lipase (Figu e 5.16). The SEM mic og aphs o PBT, PBT50Galx50 and PBGalx polyes e s be o e and a e incuba ion a e shown in Figu es 5.21 and 5.22 and in Annex E. This analysis con i med ha he su ace o PBT emained unal e ed a e being incuba ed ei he in he p esence o he absence o lipases. The esul s ob ained in he pa allel analysis ca ied ou on PBT50Galx50 and PBGalx we e Chap e 5 238 clea ly di e en . SEM mic og aphs o PBT50Galx50 showed a ce ain g ade o des uc ion o he polyme su ace when i was incuba ed in he p esence o lipase, a ea u e ha was absen when incuba ion was ca ied ou wi hou enzymes. Rega ding PBGalx, he ini ial su ace did no display any ea u e o c ys alline mo phology, and a e incuba ion wi h lipase, plen y o cu ed lines appea ed delinea ing wha seems o be a sphe uli ic ex u e. The conclusion de i ed om hese obse a ions is ha deg ada ion o PBT50Galx50 and PBGalx polyes e s unde physiological condi ions was g ea ly enhanced by he ac ion o enzymes, a p ope y ha poin s o dime hyl 2,3:4,5-di-O-me hylene-galac a a e as a po en ial comonome o ob aining biodeg adable PBT copolyes e s. Figu e 5.20. Deg ada ion o PBT, PBT50Galx50 and PBGalx. Remaining weigh (a) and molecula weigh (b) s. deg ada ion ime wi h (solid symbols) and wi hou (emp y symbols) po cine panc eas lipase a pH 7.4 a 37 ºC. Remaining weigh (a’) and molecula weigh (b’) s. deg ada ion ime a pH 2.0 a 80 ºC. Poly(bu ylene e eph hala e) copolyes e s om cyclic ace alized ca bohyd a e-based monome s 239 Figu e 5.21. SEM mic og aphs o PBGalx. Ini ial sample (a). A e incuba ion a pH=2.0 a 80 ºC o 7 days (b). A e incuba ion a pH=7.4 a 37 ºC o 56 days wi h (c) and wi hou (d) lipase om po cine panc eas. Figu e 5.22. SEM mic og aphs o PBT50Galx50. Ini ial sample (a). A e incuba ion a pH=2.0 a 80 ºC o 56 days (b). A e incuba ion a pH=7.4 a 37 ºC o 56 days wi h (c) and wi hou (d) lipase om po cine panc eas. Chap e 5 240 5.3.3.2.2. Hyd oly ic deg ada ion a pH 2.0 a 80 ºC The changes aking place in sample weigh and molecula weigh o PBT, PBT50Galx50 and PBGalx polyes e s upon incuba ion a pH 2.0 a 80 ºC a e depic ed in Figu e 5.20. The p o iles ob ained o PBT indica e again ha he e was no loss o mass and ha he dec ease in molecula weigh was p ac ically negligible. Also he SEM analysis e ealed ha PBT emained almos unal e ed a e incuba ion, only showing e y ew small c acks and con i ming he eluc ance o his polyes e o be hyd olyzed. On he con a y, PBGalx homopolyes e showed a d as ic loss o mass, abou 85% upon only 2 weeks o incuba ion and achie ing a o al weigh loss o almos 100% a e 8 weeks, as well as a signi ican dec ease in bo h Mw and Mn, which ell down o inal alues o 9,000 and 4,000 g·mol-1, espec i ely. Nei he SEM obse a ions no DSC measu emen s could be ca ied ou a e he whole pe iod o incuba ion since no sample emained; howe e , SEM obse a ions o PBGalx incuba ed o one week (Figu e 5.21) con i med ha deg ada ion o PBGalx unde hese condi ions had al eady aken place in some ex end in such a sho pe iod o ime. PBT50Galx50 copolyes e deg ada ion esul s we e in e media e be ween hose o hei espec i e wo pa en homopolyes e s, losing abou 70% o he ini ial mass and showing Mw and Mn alues o 16,000 and 7,000 g·mol-1 a e 8 weeks o incuba ion. Fu he mo e, SEM mic og aphs (Figu e 5.22) and DSC measu emen s (Figu e 5.16 and Annex E) showed ha he ini ial smoo h su ace o PBT50Galx50 was almos des oyed and c ys allini y inc eased a e incuba ion. In o de o deep insigh he deg ada ion o he polyes e chain a he molecula le el a NMR s udy was unde aken. 1H NMR spec a o he p oduc s eleased o he aqueous medium and he esidual ma e ial esul ing a e 8 weeks o incuba ion in acidic wa e a e depic ed in Figu es 5.18, 5.19 and 5.23. As expec ed, PBT spec a o bo h he aqueous medium and he esidual ma e ial did no show di e ences wi h he ini ial spec a. By con as , he PBGalx spec um o he incuba ion media showed signals co esponding o he eleased 2,3:4,5-di-O-me hylene-galac a ic acid and 1,4-bu anediol, whe eas he NMR spec um o he esidual ma e ial e ealed no changes in he diace al s uc u e bu showed -CH2OH signals o e minal g oups o he polyes e , indica ing a dec ease in he molecula weigh . On he o he hand, he NMR analysis o he incuba ion medium o PBT50Galx50 showed only signals cha ac e is ic o 2,3:4,5-di-O-me hylene- galac a ic acid and 1,4-bu anediol, whe eas he spec um o he esidual polyme showed a p og essi e dec ease in galac a ic con en . In ac , in eg a ion o galac a ic and e eph halic signals indica ed ha he esidual ma e ial con ained only 18% o he Poly(bu ylene e eph hala e) copolyes e s om cyclic ace alized ca bohyd a e-based monome s 241 galac a ic uni s a e 2 weeks o incuba ion and almos no hing a e 8 weeks. The spec um showed also p ominen -CH2OH signals due o a no able inc ease o e minal g oups. I was concluded he e o e ha a e he whole incuba ion pe iod, he esidual ma e ial o PBT50Galx50 copolyes e essen ially consis ed o 1,4-bu ylene e ep hala e oligome s. Figu e 5.23. 1H NMR spec a in D2O o he p oduc s eleased o he aqueous medium a e incuba ion o PBGalx (a) and PBT50Galx50 (b) a pH 2.0 a 80 ºC o 56 days. 5.3.3.3. S abili y o he diace al s uc u e PBT copolyes e s con aining bicyclic ace alized uni s, as well as hei espec i e suga -based homopolyes e s, ha e shown o be deg aded by wa e h ough spli ing o he es e g oup whe eas he ace al g oup emains s able agains hyd olysis (Figu es 5.18, 5.19 and 5.23). This esul is a he s iking because he ace al g oup is known o be sensi i e o acidic condi ions (Smi h and Ma ch, 2007) and he opening o he dioxolane Chap e 5 242 ings migh be expec ed o happen in some ex end. A NMR s udy was unde aken in o de o check he s abili y o he ace al g oups o he bicyclic dioxolane s uc u e, especially compa ed wi h he es e g oup. The dime hyl es e o he bicyclic ace alized galac a ic acid was hen incuba ed in aqueous bu e a pH 2.0, 7.4 and 10.5. The deg ada ion p oduc s de ec ed by NMR a e depic ed in Scheme 5.3 and he eco ded spec a a e p o ided in Annex E. A e 12 weeks o incuba ion, deg ada ion o he es e g oups happened almos quan i a i ely in bo h acid and basic media. Upon incuba ion a pH 7.4, mos o he bicyclic ace alized monome was in he dica boxylic o m, a ou h pa was as monoes e o m and only a ound 5% s ill emained as dies e . Wha was eally ema kable in his s udy is ha he ace al s uc u e s ayed unchanged a e he ea men unde any applied condi ions. Thus he s abili y agains hyd olysis obse ed o he dioxolane ings o he suga -based uni s con ained in he PBT copolyes e s was co obo a ed. Scheme 5.3. Resul ing p oduc s o he hyd olysis o dime hyl 2,3:4,5-di-O-me hylene-galac a a e a pH 2.0, pH 7.4 and pH 10.5 a e 90 days. 5.3.4. Conclusions PBT copolyes e s in which he e eph hala e uni s we e eplaced by dime hyl 2,3:4,5-di-O-me hylene-galac a a e appea ed o be sensi i e o enzyma ic ac ion showing a signi ican deg adabili y unde physiological condi ions in he p esence o lipases. When hese polyes e s we e incuba ed a 80 ºC in acidic medium, hyd oly ic deg ada ion occu ed so as ha no sample emained a e incuba ion o a ew weeks. Con e sely, PBT analogs based on 2,3:4,5-di-O-me hylene-galac i ol we e no deg aded unde Poly(bu ylene e eph hala e) copolyes e s om cyclic ace alized ca bohyd a e-based monome s 243 physiological condi ions ei he wi h o wi hou he concou se o enzymes, al hough hey displayed enhanced hyd odeg adabili y compa ed o PBT when incuba ed a 80 ºC in acidic medium. In all cases, deg ada ion p oceeded by spli ing o he ela i ely weak es e g oup associa ed o he suga moie y and wi hou modi ica ion o he diace al s uc u e. The ou s anding conclusion de i ed om his s udy is ha whe eas he inco po a ion o 2,3:4,5-di-O-me hylene-galac i ol uni s in PBT leads o copolyes e s wi h con olled hyd odeg adabili y, he inco po a ion o 2,3:4,5-di-O-me hylene-galac a a e uni s is a sui able op ion o ob aining apidly hyd odeg adable and biodeg adable PBT copolyes e s. 5.3.5. Re e ences Alla, A.; Hakkou, K.; Zamo a, F.; Ma ínez de Ila duya, A.; Galbis, J.A.; Muñoz-Gue a, S. Mac omolecules 2006, 39, 1410-1416. Bu den, I.J.; S odda , J.F. J. Chem. Soc. Pe k. T. 1 1975, 675-682. Bu le , K.; Law ance, R.L.; S acey, M. J. Chem. Soc. 1958, 740-743. Fenouillo , F.; Rosseau, A.; Colomines, G.; Sain -Loup, R.; Pascaul , J.-P. P og. Polym. Sci. 2010, 35, 578-622. Gallucci, R.R.; Pa el, B.R. Poly(bu ylene e eph hala e). In: Schei s, J.; Long, T.E.; Eds. Mode n Polyes e s, Chemis y and Technology o Polyes e s and Copolyes e s; John Wiley & Sons: Chiches e , 2004, pp. 293-321. Galbis, J.A.; Ga cía-Ma ín, M.G. Suga s as Monome s. In: Belgacem, M.N.; Gandini, A.; Eds. Monome s, Polyme s and Composi es om Renewable Resou ces; Elsel ie : Ox o d, 2008, 89-114. Gomes, M.; Gandini, A.; Sil es e, A.J.D.; Reis, B. J. Polym. Sci., Polym. Chem. 2011, 49, 3759-3768. Kiely, D.E.; Chen, L.; Lin, T.-H. J. Polym. Sci., Polym. Chem. 2000, 38, 594-603. Kijcha engkul, T.; Au as, R.; Rubino, M.; Al a ado, E.; Mon e o, J.C.R.; Rosales, J.M. Polym. Deg ad. S abil. 2010, 95, 99-107. (2010a) Kijcha engkul, T.; Au as, R.; Rubino, M.; Selke, S.; Ngouajio, M.; Fe nandez, R.T. Polym. Deg ad. S abil. 2010, 95, 2641-2647. (2010b) Kulsh es ha, A.S.; Gao, W.; G oss, RA. Mac omolecules 2005, 38, 3193-3204. La illa, C.; Alla, A.; Ma ínez de Ila duya, A.; Beni o, E.; Ga cía-Ma ín, M.G.; Galbis, J.A.; Muñoz-Gue a, S. Biomac omolecules 2011, 12, 2642-2652. -Subchap e 3.2- Chap e 5 244 La illa, C.; Alla, A.; Ma ínez de Ila duya, A.; Beni o, E.; Ga cía-Ma ín, M.G.; Galbis, J.A.; Muñoz-Gue a, S. Polyme 2012, 53, 3432-3445. -Subchap e 5.2- Nakajima-Kambe, T.; Ichihashi, F.; Ma suzoe, R.; Ka o, S.; Shin ani, N. Polym. Deg ad. S abil. 2009, 94, 1901-1905. Rych e , P.; Kawalec, M.; Sobo a, M.; Ku cok, P.; Kowalczuk, M. Biomac omolecules 2010, 11, 839-847. Smi h, M.B.; Ma ch, J. Ma ch’s Ad anced O ganic Chemis y; Wiley: Hoboken, 2007, pp. 523,1270. T ipa hy, A.R.; MacKnigh , W.J.; Kuku eka, S.N. Mac omolecules 2004, 37, 6793-6800. Yokoe, M.; Aoi, M.; Okada, M. J. Polym. Sci., Polym. Chem. 2005, 43, 3909-3919. Zaliz, C.L.R.; Va ela, O. Te ahed on Asymm. 2005, 16, 97-103. Poly(bu ylene e eph hala e) copolyes e s om cyclic ace alized ca bohyd a e-based monome s 245 5.4. Bio-based a oma ic polyes e s om a bicyclic diol de i ed om D-manni ol Summa y: 2,4:3,5-di-O-me hylene-D-manni ol, abb e ia ed as Manx, is a D-manni ol- de i ed compound wi h he seconda y hyd oxyl g oups ace alized wi h o maldehyde. The bicyclic s uc u e o Manx consis s o wo used 1,3-dioxane ings, wi h wo p ima y hyd oxyl g oups s anding ee o eac ion. A homopolyes e made o Manx and dime hyl e eph hala e, as well as a se o copolyes e s o poly(bu ylene e eph hala e) (PBT) in which 1,4-bu anediol was eplaced by Manx up o 50% we e syn hesized and cha ac e ized. The polyes e s had Mw in he 30,000-52,000 g·mol-1 ange and a andom mic os uc u e, and we e he mally s able up o nea ly 370 ºC. They displayed ou s anding high Tg wi h alues om 55 o 137 ºC which s eadily inc eased wi h he con en in Manx. Copolyes e s con aining up o 40% o Manx we e semic ys alline and adop ed he c ys al s uc u e o PBT. Thei s ess-s ain pa ame e s we e sensi i ely a ec ed by he p esence o ca bohyd a e-based uni s wi h elonga ion a b eak dec easing bu ensile s eng h and elas ic moduli s eadily inc easing wi h he deg ee o eplacemen . Publica ion de i ed om his wo k: La illa, C.; Ma ínez de Ila duya, A.; Alla, A.; Ga cía-Ma ín, M.G.; Galbis, J.A.; Muñoz- Gue a, S. Mac omolecules 2012, 45, 8257-8266. Chap e 5 252 5.4.3. Resul s and discussion 5.4.3.1. Monome syn hesis and con o ma ion The bicyclic diol 2,4:3,5-di-O-me hylene-D-manni ol (Manx) was p epa ed om D- manni ol ollowing he chemical syn he ic ou e depic ed in Scheme 5.4. P ima y hyd oxyl g oups o D-manni ol we e i s p o ec ed as benzoyl es e s and hen he addi ion o pa a o maldehyde led o cyclic ace aliza ion o he seconda y hyd oxyl g oups in he 2,4:3,5 a angemen wi h he wo used 1,3-dioxane ings. 1H and 13C NMR spec a o Manx a e shown in Annex F and de ailed in Sec ion 5.4.2. The coupling be ween he wo p o ons o he me hylene ace alic g oup wi h a J= -6.2 Hz con i ms he p esence o he wo used six membe ed ings and hen he 2,4:3,5 a angemen o he bicyclic s uc u e (Bu den and S odda , 1975). I should be s essed ha he syn hesis ou e used o he p epa a ion o Manx, al hough e ec i e o he pu pose o he wo k, is no en i onmen ally iendly. Ob iously, an al e na i e syn he ic ou e o an imp o emen o he exis ing one will need o be de eloped o make his monome o ully p ac ical use and o ende bene i s o he en i onmen . Scheme 5.4. Syn hesis o 2,4:3:5-di-O-me hylene-D-manni ol. This bicyclic diol Manx possesses a wo old axis o symme y and he e o e i s wo hyd oxyl g oups will display he same eac i i y in he polycondensa ion eac ion p oducing egio egula polyme chains. Since he wo ings a e used, a ai ly high deg ee o igidi y should be in p inciple expec ed o Manx al hough i could be la gely elie ed i Poly(bu ylene e eph hala e) copolyes e s om cyclic ace alized ca bohyd a e-based monome s 253 in e con e sion be ween possible con o me s akes place. The igidi y o he monome is c i ical o he p epa a ion o polyme s wi h imp o ed he mal and mechanical p ope ies. To app aise he e ec ha his no el diol monome will ha e on he s i ness o he polyes e s hence p oduced, a con o ma ional analysis o 1,6-di-O-benzoyl-2,4:3,5-di-O- me hylene-D-manni ol was unde aken. This dies e is an adequa e model compound o a oma ic polyes e s and copolyes e s made om Manx. The wo mos p obable con o ma ions (Mills, 1955) o he 2,4:3,5-di-O-me hylene-D-manno bicyclic s uc u e a e depic ed in Scheme 5.5. Scheme 5.5. P e e en ial con o me s o 1,6-di-O-benzoyl-2,4:3,5-di-O-me hylene-D-manni ol. In o de o assess he ela i e p e e ence o Manx o hese wo con o ma ions, a a iable empe a u e 1H NMR s udy was ca ied ou in he +60 o -60 ºC ange, and 2D- NOESY spec a we e eco ded a oom empe a u e. In he case ha I and II con o me s we e p esen , wo signals o each p o on should appea in he 1H NMR spec a a low empe a u es since no in e con e sion is expec ed o ake place unde such condi ions. On he con a y, single p o on signals we e obse ed along he whole in e al and he only de ec ed change was an up ield shi o he signals wi h hea ing (see Annex F). I can be concluded he e o e ha no con o ma ional in e con e sion occu s and ha only one con o me is p esen along he whole ange o empe a u es. The analysis o he coupling cons an s o he 1H NMR spec a sugges ed ha con o me I is he p e e ed one o Manx. In ac NMR spin simula ion using he SpinWo ks 3 p og am p o ided he spin-spin coupling cons an s (see Annex F) o he ABXYY’X’A’B’ sys em, in which small long ange couplings be ween Y and X’ p o ons we e de ec ed. The calcula ed coupling cons an s we e: JAB= JA’B’= -11.98 Hz; JAY= JA’Y’= 2.91 Hz; JBY= JB’Y’= 6.71 Hz; JYY’= JY’Y= 5.3 Hz; JYX= JY’X’= 8.60 Hz; JYX’= JY’X= -0.58 Hz Chap e 5 254 Applying hese coupling cons an s o he Ka plus equa ion de i ed o aldi ols (Ja de zky and Robe s, 1981; F anks e al., 1991), he o sional angles Ψ and Φ could be es ima ed. The alues ob ained we e 160º and 48º espec i ely, which a e e y close o he angles measu ed o con o me I bu e y a om hose o con o me II. The iden i y o con o me I as he p e e ed one was s ongly suppo ed by 2D NOESY spec um (Figu e 5.24). As expec ed o con o ma ion I, s ong NOE signals we e de ec ed o HY and one o he ace al me hylene p o ons, whe eas no NOE signals we e obse ed o HX. In con o ma ion II he sho dis ances be ween HX and one o he p o ons o he ace al me hylene should be e lec ed in he 2D spec a wi h s ong NOE signals, which is no he case. I is wo hy o no e ha c ys al s uc u e s udies on 2,4:3,5- di-O-me hylene-D-manni ol-1,6-di- ans-cinnama e (Be ns ein e al., 1980) es ablished a con o ma ion in he solid s a e o he bicyclic uni simila o which is de e mined in his wo k. The conclusion de i ed om his con o ma ional s udy is ha he p e e ed con o ma ion o Manx is I and ha his con o ma ion is well s able; such ea u es will con e o his monome an enhancing s i ness e ec on he polyme chain in which i is inse ed. Figu e 5.24. 2D NOESY spec um o 1,6-di-O-benzoyl-2,4:3,5-di-O-me hylene-D-manni ol. Small a ows indica e NOE signals. Poly(bu ylene e eph hala e) copolyes e s om cyclic ace alized ca bohyd a e-based monome s 255 5.4.3.2. Polyme syn hesis and chemical s uc u e The polyme iza ions in ol ing 2,4:3,5-di-O-me hylene-D-manni ol we e ca ied ou in he o al absence o sol en s o imi a e as a as possible he condi ions usually applied in he indus ial p ac ice. PManxT homopolyes e , om 2,4:3,5-di-O-me hylene-D- manni ol and dime hyl e eph hala e, as well as PBxManxyT copolyes e s om 2,4:3,5-di- O-me hylene-D-manni ol, 1,4-bu anediol and dime hyl e eph hala e, we e p epa ed by a wo-s ep mel -polycondensa ion p ocess using DBTO as ca alys (Scheme 5.6). Fo compa ison pu poses, he pa en PBT homopolyes e was ob ained om 1,4-bu anediol and dime hyl e eph hala e using he same polycondensa ion p ocedu e. In he p epa a ion o PBxManxyT copolyes e s, he inco po a ion o he diols in o he copolyes e s was accu a ely con olled by using a 5% mola excess o he diol mix u e o dime hyl e eph hala e, and by ini ia ing anses e i ica ion eac ions a mild empe a u e o p e en ola iliza ion o diols. Tempe a u e was p og essi ely inc eased o a oid c ys alliza ion o oligome s, and polycondensa ion eac ions we e pe o med a empe a u es be ween 210 and 240 ºC and unde acuum o acili a e he emo al o ola ile by-p oduc s; lowe empe a u es and longe eac ion imes we e used in copolyes e s wi h highe con en s in Manx o minimize he decomposi ion o his suga compound. When polyme iza ions we e ended, he eac ion mix u es we e dissol ed ei he in chlo o o m o in a mix u e o chlo o o m and i luo oace ic acid, and p ecipi a ed in me hanol o ob ain he polyme s in yields close o 85-90%. The syn hesis esul s ob ained o suga -based PManxT homopolyes e and PBxManxyT copolyes e s a e ga he ed in Table 5.7 oge he wi h da a o he pa en PBT homopolyes e . Scheme 5.6. Polyme iza ion eac ions leading o PBxManxyT copolyes e s. Chap e 5 256 Table 5.7. Mola composi ion, molecula weigh and mic os uc u e o PBxManxyT copolyes e s. Copolyes e Mola composi ion Molecula weigh Mic os uc u e Yield (%) Feed Copolyes e a Dyads Numbe A e age Sequence Leng hs Randomnessd XB XManx XB XManx [η]b Mnc Mwc Ðc BB BManx/ ManxB ManxManx nB nManx R PBT 90 100 0 100 0 0.93 17,100 (11,800) 41,300 (40,500) 2.4 (3.4) PB90Manx10T 86 90 10 91.0 9.0 1.18 20,300 (14,200) 51,200 (50,800) 2.5 (3.6) 75.6 21.7 2.7 8.0 1.3 0.92 PB80Manx20T 87 80 20 80.3 19.7 0.84 16,500 (11,500) 41,000 (40,200) 2.5 (3.5) 59.9 34.0 6.1 4.5 1.4 0.96 PB70Manx30T 86 70 30 69.2 30.8 0.75 16,600 (10,400) 38,500 (37,900) 2.3 (3.6) 44.9 44.0 11.1 3.0 1.5 0.99 PB60Manx40T 85 60 40 59.2 40.8 0.83 16,400 (11,600) 40,100 (39,800) 2.4 (3.4) 35.0 47.8 17.2 2.5 1.7 0.99 PB50Manx50T 88 50 50 49.0 51.0 0.77 16,300 (10,900) 38,900 (38,400) 2.4 (3.5) 23.1 48.4 28.5 2.0 2.2 0.97 PManxT 85 0 100 0 100 0.51 12,900 (8,100) 30,200 (29,300) 2.3 (3.6) a Mola composi ion de e mined by in eg a ion o he 1H NMR spec a. b In insic iscosi y in dL·g-1 measu ed in dichlo oace ic acid a 25 ºC. c Numbe and weigh -a e age molecula weigh s in g·mol-1 and dispe si ies measu ed by GPC in HFIP agains PMMA s anda ds a e (wi hou pa en heses) and be o e pu i ica ion (in pa en heses). d Randomness index o copolyes e s s a is ically calcula ed on he basis o he 13C NMR analysis. Poly(bu ylene e eph hala e) copolyes e s om cyclic ace alized ca bohyd a e-based monome s 257 The p ecipi a ed PBxManxyT copolyes e s we e ob ained wi h in insic iscosi ies be ween 0.8 and 1.2 dL·g-1, weigh -a e age molecula weigh s con ined in he 38,000- 52,000 g·mol-1 in e al, and dispe si ies in he 2.3-2.5 ange. Molecula weigh s o PBxManxyT copolyes e s sligh ly decay wi h he con en in Manx, in acco dance wi h he alues obse ed o PManxT homopolyes e . The GPC analysis o he eac ion p oduc (wi hou being subjec ed o any ea men ) a o ded weigh -a e age molecula weigh s e y close o hose ob ained o he p ecipi a ed p oduc bu wi h signi ican ly highe dispe si ies. Such di e ences indica e he p esence o mino amoun s o oligome ic ac ions o emaining monome s in he aw p oduc ha we e hen emo ed by p ecipi a ion. The 1H NMR spec a co obo a ed he chemical s uc u e o he copolyes e s wi h all signals being co ec ly assigned o he di e en p o ons con ained in hei epea ing uni s (Figu e 5.25). In eg a ion o he p o on signals a ising om B and Manx uni s led o quan i y he composi ion o he copolyes e s in such uni s. Da a p o ided by his analysis a e gi en in Table 5.7, showing ha all copolyes e s had composi ions e y close o hose o hei co esponding eeds. Figu e 5.25. Compa ed 1H NMR spec a o PBxManxyT copolyes e s. Chap e 5 258 The mic os uc u e o PBxManxyT copolyes e s was de e mined by 13C NMR analysis. The signals o all he magne ically di e en ca bons con ained in he epea ing uni s o he copolyes e s appea well esol ed in he 13C NMR spec a (see Annex F) and in pa icula hose a ising om he nonp o ona ed a oma ic ca bons, which come ou o be sensi i e o sequence e ec s a he dyad le el. As shown in Figu e 5.26 o he whole se o PBxManxyT copolyes e s, each esonance o he nonp o ona ed a oma ic ca bons appea s spli so ha ou peaks a e seen in he 133-135 ppm chemical shi in e al co esponding o he h ee ypes o dyads (BB, BManx and ManxB, ManxManx) ha a e easible along he copolyes e chain. By in eg a ion o hese peaks, he dyad con en s, he numbe -a e age sequence leng hs and he deg ee o andomness we e es ima ed (Table 5.7), leading o he conclusion ha he mic os uc u e o he copolyes e s was andom in all cases. Figu e 5.26. 13C NMR signals used o he mic os uc u e analysis o PBxManxyT copolyes e s wi h indica ion o he dyads o which hey a e assigned. 5.4.3.3. The mal p ope ies 2,4:3,5-di-O-me hylene-D-manni ol is a he mally ai ly s able solid compound which s a s o ola ilize abo e 150 ºC and displays a sublima ion empe a u e o 280 ºC wi hou pe cei able decomposi ion. The he mal s abili y o PManxT homopolyes e and PBxManxyT copolyes e s made om his compound was e alua ed by he mog a ime y Poly(bu ylene e eph hala e) copolyes e s om cyclic ace alized ca bohyd a e-based monome s 259 unde ine a mosphe e and compa ed wi h ha displayed by PBT. TGA aces a e depic ed in Figu e 5.27, and he mal da a p o ided by his analysis a e p esen ed in Table 5.8. The weigh loss p o iles gene a ed e eal ha all polyes e s s a o decompose well abo e 360 ºC wi h a he mal deg ada ion mechanism in ol ing one main s ep wi h he maximum a e a empe a u es s eadily inc easing wi h he con en in Manx uni s. The same end is obse ed o ºT5%, and hese esul s a e in acco dance wi h he high he mal s abili y obse ed o PManxT homopolyes e , wi h ºT5% and maxTd a 378 and 421 ºC, espec i ely. The aluable conclusion d awn om his he mog a ime ic s udy is ha he inse ion o Manx uni s in a oma ic polyes e s ins ead o educing hei he mal s abili y con ibu es o a signi ican inc ease in hei decomposi ion empe a u es. The ac o imp o ing he he mal s abili y o commonly used a oma ic polyes e s such as PBT can b oaden e en mo e he applica ion window o hese ma e ials. Figu e 5.27. (a) TGA aces (solid lines) and de i a i e cu es (dashed lines) o PBT and PManxT homopolyes e s. (b) TGA aces o PBxManxyT copolyes e s. Chap e 5 260 Table 5.8. The mal p ope ies o PBxManxyT copolyes e s. Copolyes e TGA DSC Fi s hea inge Coolinge Second hea inge ºT5%a Tdb W c Tgd Tm ΔHm Tc ΔHc Tm ΔHm (ºC) (ºC) (%) (ºC) (ºC) (J·g-1) (ºC) (J·g-1) (ºC) (J·g-1) PBT 371 408 2 31 223 (223) 56.2 (54.3) 196 43.3 223 44.0 PB90Manx10T 371 408 3 55 197 (196) 34.1 (33.0) 159 30.4 198 31.3 PB80Manx20T 372 410 8 66 184 (183) 26.0 (27.0) 140 23.4 184 24.1 PB70Manx30T 374 411 8 77 162 (162) 5.5 (16.6) - - - - PB60Manx40T 376 411 9 88 122 (119) 5.0 (9.8) - - - - PB50Manx50T 377 412 11 100 - - - - - - PManxT 378 421 13 137 - - - - - - aTempe a u e a which 5% weigh loss was obse ed. bTempe a u e o maximum deg ada ion a e. cRemaining weigh a 600 ºC. dGlass- ansi ion empe a u e aken as he in lec ion poin o he hea ing DSC aces o mel -quenched samples eco ded a 20 ºC·min-1. eMel ing (Tm) and c ys alliza ion (Tc) empe a u es, and mel ing (ΔHm) and c ys alliza ion (ΔHc) en halpies measu ed by DSC a hea ing/cooling a es o 10 ºC·min-1 o p ecipi a ed samples (wi hou pa en heses) and o ilms (in pa en heses). O he he mal p ope ies o p ime impo ance in connec ion wi h he po en ial applica ion o hese polyes e s a e he glass- ansi ion empe a u e (Tg) and he mel ing empe a u e (Tm). Fo ins ance, an inc ease in he Tg o hese polyes e s could open hei use in he ho - illed and pas eu ized-con aine ields. The glass- ansi ion empe a u es o he PManxT and PBT homopolyes e s and PBxManxyT copolyes e s we e measu ed as he in lec ion poin o he hea ing DSC aces o samples quenched om he mel . A ema kable ea u e o PManxT homopolyes e is ha i has a Tg mo e han 100 ºC highe han he a oma ic PBT homopolyes e . Rega ding PBxManxyT copolyes e s, hei Tg inc ease s eadily wi h he con en in Manx uni s, wi h minimum and maximum alues co esponding o hei espec i e PBT and PManxT homopolyes e s (Figu e 5.28), as should be expec ed om hei s a is ical mic os uc u e. As expec ed om i s cyclic s i na u e, he e ec o Manx on Tg o PBT is la gely g ea e han ha exe ed by he Poly(bu ylene e eph hala e) copolyes e s om cyclic ace alized ca bohyd a e-based monome s 261 inco po a ion o acyclic suga uni s such as ime hoxy xyli ol o L-a abini ol (Alla e al., 2006). I has e en a much mo e p onounced e ec han 2,3:4,5-di-O-me hylene- galac i ol, ano he ace alized suga diol cons i u ed by wo non- used dioxolane ings, which has been ecen ly epo ed by us as capable o aising he Tg o PBT by nea 30 ºC when i eplaces 1,4-bu anediol in a 40% (La illa e al., 2012b -Subchap e 5.2-). The e ec o Manx u ns o be simila o ha o isoso bide; in ac , bo h PBT copolyes e s con aining 40% o ei he Manx o isoso bide (K icheldo e al., 2007; Sablong e al., 2008) display a Tg o a ound 90 ºC. No doub he used bicyclic s uc u e cha ac e is ic o bo h Manx and isoso bide is unique in p o iding he polyes e chain wi h a deg ee o s i ness no achie able wi h he inse ion o o able bicyclic uni s, as i is he case o he ace alized hexi ol wi h galac o con igu a ion. Figu e 5.28. Glass- ansi ion empe a u e e sus composi ion plo o PBT copolyes e s con aining 2,4:3,5-di-O-me hylene-D-manni ol (Manx), 2,3:4,5-di-O-me hylene-galac i ol (Galx) (La illa e al., 2012b -Subchap e 5.2-), 2,3,4- i-O-me hyl-L-a abini ol (A ) o 2,3,4- i-O-me hylxyli ol (Xy) (Alla e al., 2006). DSC aces o polyes e s in he powde ed o m egis e ed a i s hea ing a e depic ed in Figu e 5.29. PBxManxyT copolyes e s wi h mola con en s in Manx below o equal o 40%, as well as PBT homopolyes e , ga e hea ing aces wi h mel ing endo he ms indica ing ha hey a e semic ys alline. Compa ison o mel ing empe a u es and en halpies o semic ys alline PBxManxyT copolyes e s wi h ha o PBT homopolyes e leads o he conclusion ha he inse ion o Manx uni s gi es place o a signi ican dec ease in bo h Tm and ΔHm (Table 5.8). PB50Manx50T copolyes e as well as PManxT homopolyes e appea o be amo phous. DSC da a eco ded om polyes e Chap e 5 268 5.4.5. Re e ences Alla, A.; Hakkou, K.; Zamo a, F.; Ma ínez de Ila duya, A.; Galbis, J.A.; Muñoz-Gue a, S. Mac omolecules 2006, 39, 1410-1416. Be ns ein, J.; G een, B.S.; Rej ö, M. J. Am. Chem. Soc. 1980, 102, 323-328. B igl, P.; G une , H. Be . 1932, 65B, 641-645. Bu den, I.J.; S odda , J.F. J. Chem. Soc. Pe k. T 1 1975, 7, 666-674. Chen, G.Q.; Pa el, M.K. Chem. Re . 2012, 112, 2082-2099. Fenouillo , F.; Rousseau, A.; Colomines, G.; Sain -Loup, R.; Pascaul , J.P. P og. Polym. Sci. 2010, 35, 578-622. F anks, F.; Dadok, J.; Ying, S.; Kay, R.L.; G ige a, J.R. J Chem. Soc. Fa aday T ans. 1991, 87, 579-585. Gallucci, R.R.; Pa el, B.R. 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Sablong, R.; Ducha eau, R.; Koning, C.E.; de Wi , G.; an Es, D.; Koelewijn, R.; an Ha e en, J. Biomac omolecules 2008, 9, 3090-3097. S o beck, R.; Ballau , M. J. Appl. Polym. Sci. 1996, 59, 1199-1202. T ipa hy, A.R.; MacKnigh , W.J.; Kuku eka, S.N. Mac omolecules 2004, 37, 6793-6800. Williams, C.K. Chem. Soc. Re . 2007, 36, 1573-1580. Wool, R.; Sun, S. Biobased Polyme s and Composi es; Academic P ess: New Yo k, 2005. Wu, J.; Edua d, P.; Thiyaga ajan, S.; Jasinska-Walc, L.; Rozanski, A.; Fonseca Gue a, C.; Noo do e , B.A.J.; an Ha e en, J.; an Es, D.S.; Koning, C.E. Mac omolecules 2012, 45, 5069-5080. Chap e 5 270 271 CHAPTER 6 SSM-PREPARED POLY(BUTYLENE TEREPHTHALATE) COPOLYESTERS FROM CYCLIC ACETALIZED CARBOHYDRATE- BASED MONOMERS Chap e 6 272 SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 273 6.1. Aim and scope o his Chap e Mos o he app oaches aimed a inc easing he glass- ansi ion empe a u e (Tg) o poly(bu ylene e eph hala e) (PBT), such as eac i e blending wi h mo e igid polyes e s and mel copolyme iza ion wi h igid comonome s, a e success ul in inc easing he glass- ansi ion empe a u e o PBT bu a he same ime se e ely comp omise he mel ing and c ys alliza ion beha io . Howe e , wi h solid-s a e modi ica ion (SSM) i is possible o exclusi ely modi y he p ope ies ela ed o he amo phous phase (i.e. glass- ansi ion empe a u e) while mo e o less e aining he c ys alliza ion beha io o he pa en polyes e . SSM consis s o making o eac a comonome wi h a semic ys alline polyme in he solid s a e, unde an ine gas low o acuum a 20-30 ºC below he Tm o he polyme bu well abo e i s Tg. SSM is based on he same p inciples as he commonly used solid-s a e polycondensa ion (SSP), which is usually employed o inc ease he molecula weigh o semic ys alline polyes e s and polyamides by anses e i ica ion and ansamida ion eac ions, espec i ely, below he Tm bu well abo e he Tg. Bo h echniques ake ad an age o he molecula mobili y in he amo phous phase o he polyme abo e Tg. Du ing SSM, only chain segmen s p esen in he mobile amo phous ac ion (MAF) o PBT a e modi ied wi h he monome . Mobili y es ic ions p e en he c ys alline phase as well as he igid amo phous ac ion (RAF) om aking pa in anses e i ica ion eac ions occu ing du ing he SSM p ocess. Among suga -based monome s, especially hose wi h a cyclic s uc u e a e o in e es , due o hei abili y o add s i ness o he polyme backbone, esul ing in enhanced Tg alues. Recen ly, high molecula weigh a oma ic copolyes e s con aining isoso bide uni s ha e been p epa ed by solid-s a e modi ica ion o PBT. Howe e , due o he ela i ely low eac i i y o he seconda y hyd oxyl g oups o isoso bide, he di ec inco po a ion o his monome in o he polyes e backbone using his echnique was no possible. The syn hesis o a mac odiol om isoso bide, e eph haloyl chlo ide and 1,4- bu anediol was necessa y o inco po a e his bicyclic monome in o PBT ia SSM. In his Chap e , he suga -based cyclic ace alized diols 2,3:4,5-di-O-me hylene- galac i ol (Galx), 2,4:3,5-di-O-me hylene-D-manni ol (Manx) and 2,3-di-O-me hylene-L- h ei ol will be di ec ly inco po a ed in o PBT. The chemical mic os uc u e and he mal Chap e 6 274 p ope ies o he esul ing bio-based copolyes e s will be discussed in de ail, and compa ed o hose o he mel polycondensa ion (MP)-p epa ed analogous copolyes e s. SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 275 6.2. Solid-s a e modi ica ion o PBT wi h cyclic ace alized galac i ol and D- manni ol: In luence o composi ion and chemical mic os uc u e on he mal p ope ies Summa y: Two bicyclic ca bohyd a e-based diols, 2,3:4,5-di-O-me hylene-galac i ol (Galx) o 2,4:3,5-di-O-me hylene-D-manni ol (Manx), we e in oduced in o he backbone o poly(bu ylene e eph hala e) using he solid-s a e modi ica ion echnique (SSM). The esul ing copolyes e s had a unique block-like chemical mic os uc u e ha endows hem wi h supe io he mal p ope ies when compa ed wi h hei andom coun e pa s ob ained by mel copolyme iza ion. The ma e ials p epa ed by SSM displayed highe mel ing poin s, c ys alliza ion empe a u es and c ys allini y, due o he p esence o long PBT sequences in he copolyes e . The glass- ansi ion empe a u es also inc eased upon inco po a ion o he bicyclic comonome s, his e ec being mo e p onounced o Manx uni s. The mel ing poin s o hese block-like copolyes e s dec eased a e mel ing due o he occu ence o andomiza ion bu hey emained highe han hose o copolyes e s p epa ed om he mel . SSM was demons a ed o be a e y sui able echnique o he inco po a ion o igid monome s in o he amo phous phase o PBT leading o bio-based non- andom copolyes e s wi h ema kable he mal p ope ies. Publica ion de i ed om his wo k: La illa, C.; Gubbels, E.; Ma ínez de Ila duya, A.; Noo do e , B.A.J.; Koning, C.E.; Muñoz-Gue a, S. Mac omolecules 2013, 46, 4335-4345. Chap e 6 276 6.2.1. In oduc ion Poly(bu ylene e eph hala e) (PBT) is a well-known semic ys alline a oma ic polyes e , cha ac e ized by a mel ing empe a u e nea 225 ºC and a high c ys alliza ion a e, which is nowadays used in a wide a ie y o enginee ing plas ic applica ions (Gallucci and Pa el, 2004). The e is a cu en g owing in e es in inc easing he glass- ansi ion empe a u e (Tg) o PBT o ex end i s use o new demanding ields like manu ac u ing o con aine s o p essu ized gaseous be e ages. In his ega d, a ious app oaches such as eac i e blending wi h mo e igid polyes e s and mel copolyme iza ion wi h igid comonome s ha e been explo ed in o de o ob ain PBT- based copolyes e s wi h enhanced Tg (Denche and Sa kisso a, 1996; Kelsey e al., 2000; San os and Gu h ie, 2006; Lo i e al., 2011). Howe e hese copolyes e s show a andom o almos andom chemical mic os uc u e wi h sho e PBT sequences, and consequen ly hey exhibi a lowe mel ing empe a u e, c ys alliza ion a e and c ys allini y wi h espec o pu e PBT. I would he e o e be desi able o p epa e PBT copolyes e s ha ing a highe Tg bu wi h a c ys allizabili y compa able o ha o PBT. This may be achie ed using he solid-s a e modi ica ion (SSM) echnique, which de i es om he solid-s a e polyme iza ion (SSP) echnique adi ionally used as a pos -polycondensa ion me hod o inc easing he molecula weigh o semic ys alline polyme s (Chang, 1970; Fo una o e al., 1981; Papaspy ides and Vouyiouka, 2009). Du ing SSM a comonome is inco po a ed in o he backbone o a semic ys alline polyme in he solid s a e, unde an ine gas low o acuum a 20-30 ºC below he mel ing empe a u e (Tm) o he polyme bu well abo e i s glass- ansi ion empe a u e (Tg); unde hese ela i ely mild condi ions, side o he mal deg ada ion eac ions a e minimized o e en e ec i ely supp essed. The SSM echnique akes bene i om he molecula mobili y p esen a empe a u es abo e Tg o inse he comonome in o he mobile amo phous phase o he polyes e , whe eas he chain segmen s in he igid amo phous ac ion and he c ys alline phase do no pa icipa e in he anses e i ica ion eac ions (Jansen e al., 2005 and 2006). Thus, SSM allows o he exclusi e modi ica ion o he p ope ies conce ning he amo phous phase and hence, he c ys alliza ion beha io o he esul ing copolyme s should be qui e compa able wi h ha o he s a ing ma e ial. Jansen e al. ha e epo ed on he inco po a ion o 2,2-bis-[4-(2-hyd oxye hoxy)phenyl]p opane, bis(2- hyd oxye hyl) e eph hala e and 2,2’-biphenyldime hanol in o he amo phous phase o PBT by SSM leading o block-like copolyes e s wi h unusual chemical mic os uc u es SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 277 and mo phologies (Jansen e al., 2005, 2006, 2007 and 2008). Sablong e al. ha e ecen ly used his inno a i e app oach o success ully inco po a e he hea ing sensi i e isoso bide in o PBT (Sablong e al., 2008). In o de o educe he use o pe ochemicals and o inc ease he added alue o ag icul u e was e s eams, he de elopmen o bio-based monome s and polyme s a e ecei ing excep ional a en ion nowadays (Wool and Sun, 2005; Pillai, 2010; Chen and Pa el, 2012). Ca bohyd a es a e e y p e alen and eadily a ailable compounds ha may a o d a wide a ie y o monome s sui able o making di e en classes o polyme s (Galbis and Ga cía-Ma ín, 2010; Gandini, 2011). Fo example, 2,5- u andica boxyla e is ega ded as he po en ial eplacemen o e eph halic acid in enginee ing, bo le o coa ing applica ions (Gandini e al., 2009; Gomes e al., 2011; Gubbels e al., 2013). Ca bohyd a e-based di unc ional compounds wi h a bicyclic molecula s uc u e a e ecei ing excep ional a en ion nowadays as comonome s o linea polycondensa ion because, in addi ion o hei na u al o igin, hey dis inguish by hei capaci y o p o ide s i ness o he polyme backbone and o inc ease he e o e he Tg. A well-known example is 1,4:3,6-dianhyd o-D-gluci ol, known as isoso bide, as well as o he dianhyd ohexi ol de i a i es used as monome s in he syn hesis o polyes e s wi h in e es ing p ope ies and enhanced Tg (Sablong e al., 2008; K icheldo e al., 2007; Fenouillo e al., 2010). Ano he amily o ca bohyd a e-based bicyclic monome s, which ha e ecen ly eme ged in he polycondensa ion ield, is ha ob ained by in e nal ace aliza ion o ca bohyd a es. These monome s ha e shown o be e y sui able o he p epa a ion o copolyes e s wi h enhanced Tg alues by mel polycondensa ion (La illa e al., 2011 -Subchap e 3.2-, 2012a -Subchap e 5.2-, 2012b -Subchap e 5.4-, 2013a -Subchap e 4.3- and 2013b -Subchap e 3.4-; Japu e al., 2012). In his wo k, wo bicyclic ace alized ca bohyd a e-based diols, 2,3:4,5-di-O- me hylene-galac i ol (Galx) and 2,4:3,5-di-O-me hylene-D-manni ol (Manx), ha e been inco po a ed in o PBT ia solid-s a e modi ica ion, leading o copolyes e s wi h enhanced Tg alues and a e ained mel ing beha io . PBT appea s o be a e y con enien a oma ic polyes e o ca y ou he p esen s udy due o i s ela i ely low Tm compa ed o PET, which allows he applica ion o he SSM echnique a lowe empe a u es. Galx is ob ained by ace aliza ion o galac a ic acid wi h pa a o maldehyde and subsequen educ ion; he cen osymme ic s uc u e o Galx consis s o wo non- used 1,3-dioxolane ings wi h he wo p ima y hyd oxyl g oups in exo posi ions. Manx is ob ained by ace aliza ion o 1,6-di-O-benzoyl-D-manni ol ollowed by hyd olysis o he benzoxy Chap e 6 284 b oad peak going ou a lowe elu ion ime co esponds o he unmodi ied PBT. A e 0.5 h o anses e i ica ion, a clea dec ease in in ensi y o he Manx peak was obse ed while he peak o igina ing om PBT shi ed o highe elu ion imes. This shi is indica i e o he chain scission o he PBT caused by he he anses e i ica ion eac ion wi h Manx. A SSM= 1 h, he polyme was elu ed a he highes elu ion ime o subsequen ly shi back o lowe alues. Hence, ecombina ion o he polyme chains akes place esul ing in highe Mn and Mw alues and libe a ion o 1,4-bu anediol, which di uses ou o he polyme pa icles. All he SSM p ocesses we e ollowed using SEC, wi h he aim o ob aining SSMPBxGalxyT and SSMPBxManxyT copolyes e s wi h compa able molecula weigh s, and also simila o molecula weigh s o samples p epa ed by MP (abb e ia ed he e as MPPBxGalxyT and MPPBxManxyT copolyes e s) (La illa e al., 2012a -Subchap e 5.2- and 2012b -Subchap e 5.4-), in o de o pe o m an accu a e and eliable compa ison o hei c ys alliza ion beha io . All he SSM eac ions we e s opped when Mn and Mw alues o abou 17-20 and 40-44 kg·mol-1, espec i ely, we e eached (Table 6.1). The p o on nuclea magne ic esonance (1H NMR) co obo a ed he expec ed chemical s uc u e o he copolyes e s (Figu e 6.2), wi h all esonances being assigned o he a ious p o ons p esen in he copolyes e backbone. In eg a ion o he p o on signals a ising om 1,4-bu anediol and suga uni s led o he de e mina ion o he composi ion o he copolyes e s. Da a p o ided by his analysis is gi en in Table 6.1, whe e i can be seen ha he bicyclic monome s Galx and Manx we e success ully inco po a ed in o he PBT by SSM. The inal composi ions o he copolyes e s a e compa able o he 1,4- bu anediol:suga eed composi ions. This is in con as o epo ed s udies abou he SSM o PBT using he suga -based bicyclic diol isoso bide (Is). Expe imen s using SSM o he di ec inco po a ion o Is in o PBT we e unsuccess ul; isoso bide could no be inco po a ed unde such condi ions. The syn hesis o a mac odiol om isoso bide, e eph haloyl chlo ide and 1,4-bu anediol was necessa y o inco po a e his bicyclic monome in o PBT ia SSM (Sablong e al., 2008). Ne e heless, in his p esen s udy he suga -based diol was success ully inco po a ed wi hou ha ing o e e o he p epa a ion o a suga -based mac odiol. The eason o his di e ence is mos p obably ha he p ima y hyd oxyl g oups o Galx and Manx ha e a much highe eac i i y compa ed o he seconda y hyd oxyl g oups o Is. By a ying he PBT/Galx and PBT/Manx eed a ios, six copolyes e s wi h a ious 1,4-bu anediol:suga a ios we e ob ained wi hin each se ies (Table 6.1). The composi ions and molecula weigh s o bo h SSM se ies a e compa able and a e also e y simila o he ully andom MPPBxGalxyT and MPPBxManxyT copolyes e s ob ained by polycondensa ion in he mel . SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 285 Table 6.1. Mola composi ion, molecula weigh and mic os uc u e o SSMPBxGalxyT and SSMPBxManxyT copolyes e s. Copolyes e Mola composi ion Molecula weigh Mic os uc u e Feed Copolyes e a Dyad con en Numbe A e age Sequence Leng hs Randomnessc Randomnessd XB XSuga XB XSuga Mnb Mwb Ðb NBB NBS/SB NSS nB nS R Rc PB91Galx9T 90.9 9.1 91.0 9.0 17,800 41,300 2.3 85.6 12.2 2.2 15.0 1.4 0.80 0.92 PB89Galx11T 87.0 13.0 88.7 11.3 19,800 43,600 2.2 80.3 16.2 3.5 10.9 1.4 0.79 0.93 PB86Galx14T 83.3 16.7 86.4 13.6 19,400 44,800 2.3 76.2 18.3 5.5 9.3 1.6 0.73 0.89 PB81Galx19T 80.0 20.0 80.6 19.4 17,900 43,100 2.4 65.6 24.6 9.8 6.3 1.8 0.71 0.89 PB78Galx22T 76.9 23.1 77.9 22.1 18,800 44,700 2.4 63.4 24.9 11.7 6.1 1.9 0.68 0.89 PB71Galx29T 71.4 28.6 71.0 29.0 18,500 44,000 2.4 52.9 29.3 17.8 4.6 2.2 0.67 0.85 PB92Manx8T 90.9 9.1 92.0 8.0 18,800 42,000 2.2 85.7 11.4 2.9 16.0 1.5 0.73 0.80 PB88Manx12T 87.0 13.0 88.2 11.8 17,600 41,300 2.3 78.8 15.4 5.8 11.2 1.7 0.66 0.77 PB86Manx14T 83.3 16.7 85.9 14.1 18,700 43,900 2.3 72.8 19.7 7.5 8.4 1.8 0.69 0.83 PB82Manx18T 80.0 20.0 81.5 18.5 17,100 40,800 2.4 66.4 23.1 10.5 6.7 1.9 0.67 0.83 PB77Manx23T 76.9 23.1 77.0 23.0 19,500 44,800 2.3 59.7 27.8 12.5 5.3 1.9 0.72 0.87 PB70Manx30T 71.4 28.6 69.7 30.3 17,700 40,700 2.3 52.1 29.2 18.7 4.6 2.3 0.66 0.82 a Mola composi ion de e mined by in eg a ion o he 1H NMR spec a. b Numbe and weigh -a e age molecula weigh s in g·mol-1 and dispe si ies measu ed by SEC in HFIP agains PMMA s anda ds. c Randomness index o copolyes e s s a is ically calcula ed on he basis o he 13C NMR analysis. d Randomness index o he amo phous ac ion o copolyes e s, de e mined using he co ec ion me hod epo ed by Jansen e al. (Jansen e al., 2005) Chap e 6 286 Figu e 6.2. 1H NMR spec a o SSMPBxGalxyT (a) and SSMPBxManxyT (b) copolyes e s eco ded in CDCl3/TFA a oom empe a u e. 6.2.3.2. Chemical mic os uc u e The chemical mic os uc u e o SSMPBxGalxyT and SSMPBxManxyT copolyes e s was elucida ed using quan i a i e ca bon nuclea magne ic esonance (13C NMR) spec oscopy. The esonances o all magne ically di e en ca bons p esen in he epea uni s o he copolyes e s a e well esol ed in he 13C NMR spec a, which a e shown in he Annex G. This is ue in pa icula o he esonances a ising om he non-p o ona ed a oma ic ca bons, which p o e o be sensi i e o sequence dis ibu ion a he le el o dyads (K icheldo , 1978; Newma k, 1980). The esonance o he qua e na y ca bon a om has spli in o ou well esol ed peaks which a e obse ed in he 133-135 ppm chemical shi in e al. These ou esonances co espond o he di e en ypes o dyads (BB, BS and SB, SS) ha a e p esen along he copolyes e backbone, and hey display peak a eas wi h a dependence on he copolyes e composi ion (Figu e 6.3). SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 287 Figu e 6.3. 13C NMR signals used o he mic os uc u e analysis o SSMPBxGalxyT (a) and SSMPBxManxyT (b) copolyes e s wi h indica ion o he dyads o which hey a e assigned. The mola ac ions (N) o he di e en dyads in he copolyes e s we e de e mined by he in eg a ion o hei co esponding esonances. Based on hese esul s, he numbe a e age sequence leng hs n o he bu ylene- e eph hala e (B) and suga - e eph hala e (S) sequences, as well as he deg ee o andomness (R), a e de e mined o each copolyes e by using he equa ions gi en below (Yamade a and Mu ano, 1967; Chap e 6 288 Randall, 1977). When he R is de e mined o be in he o de o uni y he chemical mic os uc u e is ully andom. I he R alue dec eases owa ds ze o, he chemical mic os uc u e becomes mo e blocky. nB = (NBB + 0.5·(NBS+NSB)) / (0.5·(NBS+NSB)) nS = (NSS + 0.5·(NBS+NSB)) / (0.5·(NBS+NSB)) R= (1/nB) + (1/nS) Resul s om hese calcula ions (Table 6.1) show ha he o e all sequence dis ibu ion in SSMPBxGalxyT and SSMPBxManxyT copolyes e s is non- andom o he whole composi ion ange used in his s udy. A low comonome con en s i was challenging o accu a ely de e mine he in eg al alues o he comonome s. The R- alues o copolyes e s wi h medium o high con en in suga we e all close o 0.70, indica ing an o e all non- andom mic os uc u e. Since he c ys alline phase does no pa icipa e in he SSM p ocess, long PBT sequences a e expec ed o be e ained in he copolyes e , which p obably lead o he obse ed de ia ion o he R- alues om uni y. In o de o asce ain in o ma ion abou he chemical mic os uc u e in he amo phous phase, a co ec ion needs o be made o he c ys alline phase. Jansen e al. ha e de eloped a calcula ion me hod o adjus he solu ion 13C NMR peak in eg al alues o he dyad sequences in such a way ha only he amo phous ac ion is accoun ed o (Jansen e al., 2005). The chemical mic os uc u es o he o al amo phous phases o SSMPBxGalxyT and SSMPBxManxyT copolyes e s we e de e mined by using his calcula ion me hod, implemen ing da a ob ained by di e en ial scanning calo ime y, which will be discussed below. The calcula ed R- alues o he amo phous phase a e shown in Table 6.1. I can be obse ed ha all he R- alues inc ease a e he co ec ion. This can be easily unde s ood because long PBT sequences ha e been excluded by his co ec ion. The co ec ed R- alues om he wo se ies a e simila , all o hem being close o uni y, hus indica ing a p ac ically andom chemical mic os uc u e in he amo phous phase. The di e ence in he R- alues be ween he wo se ies be o e co ec ion is mos likely caused by he highe c ys allini y o he Galx-based samples. The co ec ed R- alues a e depic ed in Figu e 6.4, oge he wi h o e all SSM and MP R- alues, showing ha he chemical mic os uc u es in he amo phous phases o copolyes e s p epa ed by SSM a e compa able o hose o ma e ials p epa ed by MP. Hence, by SSM Galx and Manx a e inco po a ed in o he mobile amo phous phase in a simila way as h ough mel polyme iza ion, e en hough in SSM only he mos mobile chain segmen s a e pa icipa ing in he anses e i ica ion eac ions. The main conclusion o his s udy is ha , SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 289 by using SSM, pa ially bio-based copolyes e s wi h unique chemical mic os uc u es ha e been ob ained, consis ing o a blocky o e all mic os uc u e o med by PBT homopolyme sequences in he c ys alline phase and a p ac ically andom mic os uc u e in he amo phous pa . Figu e 6.4. Compa ison o he deg ees o andomness o PBxGalxyT (a) and PBxManxyT (b) copolyes e s ob ained by SSM and MP (La illa e al., 2012a -Subchap e 5.2- and 2012b - Subchap e 5.4-). 6.2.3.3. The mal p ope ies The he mal beha io o he PBT-based copolyes e s p epa ed by SSM has been sys ema ically s udied by TGA and DSC (Table 6.2). The esul s ob ained om he wo se ies o copolyes e s a e compa ed wi h each o he , wi h he pa en homopolyes e PBT, and wi h copolyes e s p epa ed by MP. Fi s , he he mal s abili y was e alua ed by TGA unde an ine a mosphe e. The TGA aces o he comple e se s o copolyes e s a e compa a i ely depic ed in Annex G. The he mal p ope ies de i ed om he shown he mog ams, iz. onse decomposi ion empe a u es (ºT5%) and empe a u es o maximum deg ada ion a e (Td), a e lis ed in Table 6.2. Decomposi ion o all SSMPBxGalxyT and SSMPBxManxyT copolyes e s akes place in one s ep, a highe empe a u es wi h espec o nea PBT. Addi ionally, he esidual weigh le upon hea ing a 600 ºC is abou 3-7% o he ini ial weigh . These esul s a e in ull acco dance wi h he enhanced he mal s abili y obse ed o he copolyes e s p epa ed by MP compa ed o PBT (La illa e al., 2012a -Subchap e 5.2- and 2012b -Subchap e 5.4-). The aluable conclusion d awn om his compa a i e he mog a ime ic s udy is ha he inse ion o suga -based bicyclic Galx and Manx uni s in o PBT by SSM inc eases he he mal s abili y o he PBT-based copolyes e s. Chap e 6 290 Table 6.2. The mal p ope ies o SSMPBxGalxyT and SSMPBxManxyT copolyes e s. Copolyes e TGA DSC Fi s hea inge Coolinge Second hea inge ºT5%a Tdb W c Tgd Tm ΔHm Tc ΔHc Tc ΔHc Tm ΔHm (ºC) (ºC) (%) (ºC) (ºC) (J·g-1) (ºC) (J·g-1) (ºC) (J·g-1) (ºC) (J·g-1) PBT 348 385 0 45 225 60.5 193 52.0 - - 224 49.0 PB91Galx9T 350 390 4 47 218 77.9 180 48.3 - - 212 46.6 PB89Galx11T 360 399 3 49 209 71.6 176 43.8 - - 209 38.3 PB86Galx14T 350 388 5 50 207 67.5 167 41.2 - - 205 37.1 PB81Galx19T 354 391 5 54 208 56.5 143 37.5 - - 191 26.9 PB78Galx22T 354 391 4 54 208 55.9 131 32.0 - - 185 25.4 PB71Galx29T 354 391 6 57 205 41.1 - - 121 9.6 169 11.9 PB92Manx8T 363 399 4 56 211 67.3 183 41.5 - - 212 41.4 PB88Manx12T 349 388 7 62 210 64.8 170 39.0 - - 205 32.3 PB86Manx14T 364 401 6 67 208 63.5 158 38.3 - - 200 30.3 PB82Manx18T 351 389 5 68 207 56.0 140 27.3 - - 190 27.0 PB77Manx23T 362 402 6 70 206 45.4 121 2.6 139 5.1 181 8.8 PB70Manx30T 354 392 7 76 205 37.7 - - - - - - a Tempe a u e a which 5% weigh loss was obse ed. b Tempe a u e o maximum deg ada ion a e. c Remaining weigh a 600 ºC. d Glass- ansi ion empe a u e aken as he in lec ion poin o he hea ing DSC aces eco ded a 20 ºC·min-1 du ing he 3 d hea ing un. e Mel ing (Tm) and c ys alliza ion (Tc) empe a u es, and mel ing (ΔHm) and c ys alliza ion (ΔHc) en halpies measu ed by DSC a hea ing/cooling a es o 10 ºC·min-1. A e applying a simila he mal ea men which was used o he copolyes e s he ΔHm inc eased o 74.4 J/g. SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 291 The DSC analysis e ealed ha he inco po a ion o he bicyclic Galx and Manx uni s by SSM induced signi ican changes in he glass- ansi ion empe a u e (Tg) o PBT- based copolyes e s (Table 6.2). In he SSMPBxGalxyT se ies, he Tg alues s eadily augmen ed as 1,4-bu anediol was eplaced by Galx uni s, eaching a alue o 57 ºC when 29 mol% o Galx was inco po a ed, and ollowing a end simila o ha obse ed o MPPBxGalxyT copolyes e s (La illa e al., 2012a -Subchap e 5.2-). Rega ding he SSMPBxManxyT se ies, he Tg also inc eased wi h inc easing amoun o inco po a ed comonome ; in his case he e ec o he bicyclic diol on Tg was e en mo e p onounced o all he composi ions. A Tg alue o 76 ºC was eached o a Manx con en o 30 mol%. Appa en ly, he used bicyclic 1,3-dioxane s uc u e o Manx has a mo e signi ican in luence on he Tg alues han he mo e lexible s uc u e o Galx, a di e ence ha has also been no iced in copolyes e s p epa ed by MP (La illa e al.,2012b -Subchap e 5.4-). These esul s e idence he e ec ha he igid suga -based comonome exe s on es ic ing he mobili y o he copolyes e chain. Figu e 6.5. Glass- ansi ion empe a u e e sus composi ion plo s o SSM and MP (La illa e al., 2012a -Subchap e 5.2- and 2012b -Subchap e 5.4-) copolyes e s. (a) PBxGalxyT and (b) PBxManxyT. The glass- ansi ion empe a u es we e ob ained om he hi d hea ing un. The iangle ep esen s he Tg o he homopolyes e PBT. Chap e 6 292 Mel ing empe a u es (Tm) and en halpies (ΔHm), and c ys alliza ion empe a u es (Tc) and en halpies (ΔHc) we e measu ed using di e en ial scanning calo ime y (DSC) and a e lis ed in Table 6.2. Fo illus a ion, he DSC aces o SSMPB81Galx19T, eco ded upon hea ing and cooling, a e depic ed in Annex G. A dec ease in Tm and ΔHm can be seen when he i s and second hea ing uns a e compa ed, his beha io will be discussed la e in his a icle. All he p epa ed SSMPBxGalxyT and SSMPBxManxyT copolyes e s a e semic ys alline and exhibi a Tm alue exceeding 205 ºC in he i s hea ing un. This Tm co esponds o he c ys alline po ion o he ma e ial which did no pa icipa e in he SSM eac ion. Mel ing empe a u e e sus composi ion plo s o SSMPBxGalxyT and SSMPBxManxyT copolyes e s a e compa a i ely depic ed in Figu e 6.6, oge he wi h da a o he co esponding copolyes e s ob ained by MP. Whe eas mel ing empe a u es o MPPBxGalxyT and MPPBxManxyT sha ply dec ease wi h inc easing amoun s o suga -based uni s, he Tm o he copolyes e s p epa ed by SSM did no p esen such a endency. Mo eo e , he di e ence be ween he Tm alues o ma e ials p epa ed by SSM and MP is mo e p onounced as he suga con en inc eases. These esul s p o ed ha , by means o SSM, i is possible o p epa e suga -based PBT copolyes e s wi h only mode a ely dec easing mel ing empe a u es. Figu e 6.6. Mel ing empe a u e e sus composi ion plo s o SSM and MP (La illa e al., 2012a -Subchap e 5.2- and 2012b -Subchap e 5.4-) copolyes e s. (a) PBxGalxyT and (b) PBxManxyT. The iangle ep esen s he mel ing empe a u e o he homopolyes e PBT. SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 293 The copolyes e s ob ained by SSM ha e ela i ely high mel ing en halpies (Table 6.2), especially compa ed o hose p epa ed by MP (La illa e al., 2012a - Subchap e 5.2- and 2012b -Subchap e 5.4-). This inc ease is due o annealing occu ing du ing he SSM eac ion. The esul s p esen ed in Table 6.2 sugges ha small amoun s o he monome p esen in he i s SSM s ages could ac as a plas icize , hus inc easing he molecula mobili y o he polyme chains and a o ing annealing. Howe e , a dec ease in he mel ing en halpy was obse ed when he amoun o suga -based comonome was inc eased u he . In o de o de e mine he c ys allini y o SSMPBxGalxyT and SSMPBxManxyT copolyes e s, o elucida e i co-c ys alliza ion is aking place and o complemen he DSC da a, wide-angle X- ay di ac ion (WAXD) was pe o med on he wo se ies o copolyes e s as well as on nea PBT. The powde WAXD p o iles a e shown in Figu e 6.7, and he mos p ominen B agg spacings p esen he ein a e lis ed in Table 6.3. Figu e 6.7. Powde WAXD p o iles o SSMPBxGalxyT (a) and SSMPBxManxyT (b) copolyes e s wi h indica ion o dhkl in Å. Chap e 6 300 SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 301 6.3. Ca bohyd a e-based PBT copolyes e s om a cyclic diol de i ed om na u ally occu ing a a ic acid: A compa a i e s udy ega ding mel polycondensa ion and solid-s a e modi ica ion Summa y: 2,3-di-O-me hylene-L- h ei ol (Thx) is a cyclic ca bohyd a e-based diol p epa ed by ace aliza ion and subsequen educ ion o he na u ally occu ing a a ic acid. The s uc u e o Thx consis s o a 1,3-dioxolane ing wi h wo a ached p ima y hyd oxyl g oups. Two se ies o pa ially bio-based poly(bu ylene e eph hala e) (PBT) copolyes e s we e p epa ed using Thx as comonome by mel polycondensa ion (MP) and solid-s a e modi ica ion (SSM). Fully andom copolyes e s we e ob ained a e MP using mix u es o Thx and 1,4-bu anediol in he eac ion wi h dime hyl e eph hala e. Copolyes e s wi h a unique block-like chemical mic os uc u e we e p epa ed by inco po a ion o Thx in o he amo phous phase o PBT by SSM. The pa ial eplacemen o 1,4-bu anediol uni s by Thx esul ed in sa is ac o y he mal s abili ies and ga e ise o an inc ease in Tg alues, and his e ec was compa able o copolyes e s p epa ed by MP and SSM. The pa ially bio-based ma e ials p epa ed by SSM displayed highe mel ing poin s and easie c ys alliza ion om he mel , due o he p esence o long PBT sequences in he backbone o he copolyes e . The inco po a ion o Thx in he copolyes e backbone enhanced he hyd oly ic deg ada ion o he ma e ials wi h espec o he deg ada ion o pu e PBT. Publica ion de i ed om his wo k: La illa, C.; Gubbels, E.; Alla, A.; Ma ínez de Ila duya, A.; Noo do e , B.A.J.; Koning, C.E.; Muñoz-Gue a, S. (Submi ed 2013) Chap e 6 302 6.3.1. In oduc ion Na u e p oduces app ox. 140·109 ons o ca bohyd a es om ca bon dioxide and wa e annually, making hese compounds he mos abundan o ganic ma e ials on ea h. Humani y only uses 4% o his eeds ock o ood and non- ood pu poses (Lich en hale , 2010). The e o e his class o compounds is an ex ao dina y sou ce o chemicals, capable o p o iding a wide a ie y o building blocks o polycondensa es (Wool and Sun, 2005; Galbis and Ga cía-Ma ín, 2008; Pillai, 2010). Thus, he de elopmen o ca bohyd a e-based polycondensa es has he po en ial o signi ican ly educe he amoun o pe oleum consumed o polyme p oduc ion. Howe e , he e a e only a ew examples o comme cially a ailable ca bohyd a e-de i ed polyme s, which is mainly due o he ela i ely high p ice o hese ma e ials compa ed o hei pe oleum-based coun e pa s. Ano he limi a ion o ca bohyd a es as building blocks in he syn hesis o linea polycondensa es is hei inhe en mul i unc ionali y. Al hough some linea polycondensa es ha e been syn hesized using ca bohyd a e-based monome s bea ing pendan hyd oxyl g oups (Kiely e al., 1994 and 2000), he mos commonly used s a egy is blocking hem wi h s able p o ec ing g oups, and hus e aining only wo eac i e unc ions o ca y ou linea polycondensa ion (Galbis and Ga cía-Ma ín, 2010; Gandini, 2011). Among ca bohyd a es, a a ic acid (2,3-dihyd oxy-succinic acid) s ands ou by i s easy accessibili y and ela i e simplici y in e ms o i s molecula s uc u e. This hyd oxyla ed alda ic acid occu s in many plan s and e men ed g ape juice (Blai and DeF a ies, 2000). F om a a ic acid, a ious monome s ha e been p epa ed and explo ed as ca bohyd a e-based building blocks in he syn hesis o polycondensa es, usually wi h he pendan hyd oxyl g oups p o ec ed in se e al o ms (Alla e al., 2000 and 2005; Kin e al., 2001; Ma ín and Muñoz-Gue a, 2008; Japu e al., 2013). A oma ic polyes e s a e used in a wide a ay o applica ions due o hei high pe o mance as he moplas ic ma e ials wi h good he mal and mechanical p ope ies (Gallucci and Pa el, 2004). The p ope ies o such a oma ic polyes e s can be adjus ed by copolyme iza ion, p e e ably wi h bio-based comonome s, in o de o make hese ma e ials mo e en i onmen ally iendly and mo e sus ainable (Li e al., 2012). Howe e , he inco po a ion o bio-based acyclic monome s usually esul s in a lowe ed glass- ansi ion empe a u e and educed s i ness (Kin e al., 2001; Zamo a e al., 2005; Li e al., 2012). Fo example, 2,3-di-O-me hyl-L- h ei ol, an acyclic diol wi h i s seconda y hyd oxyl g oups p o ec ed as me hoxy e he s, has been employed in he p epa a ion o a oma ic SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 303 copolyes e s (Kin e al., 2001). On he o he hand, ca bohyd a e-de i ed monome s wi h a cyclic s uc u e dis inguish hemsel es by p o iding polycondensa es wi h imp o ed p ope ies, especially hose ela ed o polyme chain s i ness (K icheldo e al., 2007; Gandini, 2009; Fenouillo e al., 2010; Gubbels e al., 2013a; La illa e al., 2013a -Subchap e 4.3-). Two cyclic ace alized ca bohyd a e-based diols de i ed om a a ic acid, i.e. 2,3-di-O-isop opylidene-L- h ei ol and 2,3-di-O-me hylene-L- h ei ol, wi h he pendan unc ional g oups p o ec ed as isop opylidene ace al and me hylene ace al, espec i ely, ha e been ecen ly employed in he p epa a ion o polyu e hanes (Ma ín and Muñoz-Gue a, 2008). In his wo k, he cyclic diol 2,3-di-O-me hylene-L- h ei ol (Thx) is employed as building block o he p epa a ion o poly(bu ylene e eph hala e) (PBT) copolyes e s. Whe eas isop opylidene ace als a e known o be uns able and easily emo ed in acidic media (Ma ín and Muñoz-Gue a, 2008; Gómez and Va ela, 2009; Dhamaniya and Jacob, 2010), he p o ec ion by me hylene ace al g oups allows o he p epa a ion o polycondensa es wi h a sa is ac o y s abili y du ing p ocessing and handling, since he me hylene ace al ings a e much mo e esis an o opening (La illa and Muñoz-Gue a, 2012 -Subchap e 5.3-; La illa e al., 2013b -Subchap e 3.4-). Two di e en echniques, i.e. mel polycondensa ion (MP) and solid-s a e modi ica ion (SSM), will be used o p epa e he no el bio-based copolyes e s om he a o emen ioned Thx. The widely known MP echnique consis s o eac ing he monome s Thx, 1,4-bu anediol, and dime hyl e eph hala e in he mel , iz. in wo successi e s ages in ol ing anses e i ica ion and polycondensa ion eac ions. The SSM echnique (Jansen e al., 2006) is based on he same p inciples as he commonly used solid-s a e polycondensa ion (SSP), which is usually employed o inc ease he molecula weigh o semic ys alline polyes e s and polyamides by anses e i ica ion and ansamida ion eac ions, espec i ely (Vouyiouka e al., 2005; Papaspy ides and Vouyiouka, 2009). Bo h SSM and SSP echniques a e ca ied ou a a eac ion empe a u e jus (20-30 °C) below he mel ing empe a u e o he c ys alline phase o he polyme , and hey ake ad an age o he molecula mobili y in he amo phous phase o he polyme ela i ely a abo e Tg. Du ing he SSM p ocess, he monome Thx is inse ed exclusi ely in o he mobile amo phous ac ion (MAF) o poly(bu ylene e eph hala e); mobili y es ic ions p e en he c ys alline phase and he igid amo phous ac ion (RAF) om aking pa in anses e i ica ion eac ions (Jansen e al., 2005; Gubbels e al., 2013b; La illa e al, 2013c -Subchap e 6.2-). The syn hesis, chemical mic os uc u e and he mal p ope ies o he esul ing MP- and SSM-p epa ed bio-based copolyes e s will be s udied and Chap e 6 304 discussed in de ail. Mo eo e , a hyd oly ic deg ada ion s udy will be ca ied ou o e alua e he in luence o he Thx uni s on he deg ada ion o he copolyes e , and o asce ain he s abili y o he ace al g oup o ming pa o he ca bohyd a e-based esidues. 6.3.2. Expe imen al sec ion 6.3.2.1. Ma e ials The cyclic diol 2,3-di-O-me hylene-L- h ei ol (Thx) was syn hesized om comme cially a ailable dime hyl L- a a e, as desc ibed elsewe e (Ma ín and Muñoz- Gue a, 2008). The eagen s 1,4-bu anediol (99%), dime hyl e eph hala e (99+%) and he ca alys dibu yl in oxide (DBTO, 98%) we e pu chased om Sigma-Ald ich. PBT was a kind gi om DSM. Deu e a ed chlo o o m (CDCl3, 99.8% a om D) and deu e a ed i luo oace ic acid (TFA-d, 99% a om D) we e ob ained om Camb idge Iso ope Labo a o ies. Sol en s used o pu i ica ion and cha ac e iza ion we e pu chased om Pan eac and Biosol e and hese we e all o ei he echnical o high-pu i y g ade. All chemicals we e used as ecei ed unless s a ed o he wise. 6.3.2.2. Gene al me hods 1H and 13C NMR spec a we e eco ded on a B uke AMX-300 spec ome e a 25.0 ºC ope a ing a 300.1 and 75.5 MHz, espec i ely. Samples we e dissol ed in a mix u e o deu e a ed chlo o o m and deu e a ed i luo oace ic acid (9:1), and spec a we e in e nally e e enced o e ame hylsilane (TMS). App oxima ely 10 and 50 mg o sample dissol ed in 1 mL o he sol en mix u e we e used o 1H and 13C NMR, espec i ely. Six y- ou scans we e acqui ed o 1H and 1,000-10,000 o 13C wi h 32 and 64-K da a poin s as well as elaxa ion delays o 1 and 2 s, espec i ely. Size-exclusion ch oma og aphy (SEC) was pe o med on a sys em equipped wi h a Wa e s 1515 Isoc a ic HPLC pump, a Wa e s 2414 e ac i e index de ec o wo king a 40 ºC, a Wa e s 2707 au osample , and a PSS PFG gua d column ollowed by a 2PFG-linea -XL (7 μm, 8·300 mm) columns in se ies a 40 ºC. HFIP wi h po assium i luo oace a e (3 g·L-1) was used as eluen a a low a e o 0.8 mL·min-1. The molecula weigh s we e calcula ed agains polyme hyl me hac yla e s anda ds (Polyme Labo a o ies, Mp= 580 Da up o Mp= 7.1·106 Da). Di e en ial scanning calo ime y (DSC) was pe o med using a Pe kin Elme DSC Py is 1 equipmen . DSC he mog ams we e ob ained om 3 o 5 mg samples a SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 305 hea ing/cooling a es o 10 ºC·min-1 unde a ni ogen low o 20 mL·min-1. Indium and zinc we e used as s anda ds o empe a u e and en halpy calib a ion. The glass- ansi ion empe a u es we e de e mined om he hi d hea ing un a a hea ing a e o 20 ºC·min-1 om apidly mel -quenched polyme samples. The ea men o he samples o iso he mal c ys alliza ion expe imen s was he ollowing: he he mal his o y was emo ed by hea ing he sample up o 250 ºC and keeping he sample a his empe a u e o 5 min, subsequen ly i was cooled a 20 ºC·min-1 o he selec ed c ys alliza ion empe a u e, whe e i was le o c ys allize un il sa u a ion. The mog a ime ic analyses we e pe o med unde a ni ogen low o 20 mL·min-1 a a hea ing a e o 10 ºC·min-1, wi hin a empe a u e ange o 30 o 600 ºC, using a Pe kin Elme TGA 6 equipmen . Sample weigh s o abou 10-15 mg we e used in hese expe imen s. Wide-angle X- ay di ac ion (WAXD) measu emen s we e pe o med on a Rigaku Geige lex B agg-B en ano Powde Di ac ome e using Cu adia ion, wa eleng h 1.54056 Å, a 40 kV and 30 mA. The scans we e pe o med wi h 0.02 º s eps and a dwell ime o 3 s in he 2θ ange om 10 º ill 35 º. The analyses we e pe o med on he c ude copolyes e samples. Scanning elec on mic oscopy (SEM) images we e aken wi h a ield-emission JEOL JSM-7001F ins umen (JEOL, Japan) om pla inum/palladium coa ed samples. 6.3.2.3. Polyme syn hesis 6.3.2.3.1. Mel polycondensa ion (MP) Thx-based copolyes e s we e ob ained om a mix u e o 1,4-bu anediol, he cyclic diol 2,3-di-O-me hylene-L- h ei ol (Thx) and dime hyl e eph hala e (DMT) wi h a p ede e mined composi ion. PThxT homopolyes e was ob ained by eac ing Thx wi h DMT. The eac ions we e pe o med in a h ee-necked, cylind ical-bo om lask equipped wi h a mechanical s i e , a ni ogen inle and a acuum dis illa ion ou le . A 5% mola excess o he diol mix u e o DMT was used, and dibu yl in oxide (DBTO, 0.6% mola wi h espec o monome s) was he ca alys o choice. The appa a us was pu ged wi h ni ogen se e al imes a oom empe a u e in o de o emo e he las aces o ai . T anses e i ica ion eac ions we e ca ied ou unde a low ni ogen low a he selec ed empe a u e. Polycondensa ion eac ions we e pe o med a a selec ed empe a u e unde a 0.03-0.06 mba acuum. A he end o he eac ion, he eac ion mix u e was cooled o oom empe a u e unde a ni ogen a mosphe e. The esul ing polyme s we e dissol ed in a mix u e o chlo o o m and i luo oace ic acid (9:1) and p ecipi a ed in an excess o me hanol. Finally, he polyme was collec ed by il a ion, ex ensi ely washed wi h me hanol and d ied unde acuum. The de ailed eac ion condi ions a e gi en below. Chap e 6 306 The Thx-based copolyes e s ob ained ia MP a e abb e ia ed as MPPBxThxyT, whe e x and y a e he mole pe cen ages (mol-%) o 1,4-bu anediol and Thx, espec i ely, in he esul ing copolyes e . PThxT homopolyes e . T anses e i ica ion eac ions we e pe o med a 160 ºC o 2 h and a 180 ºC o 1 h unde a low ni ogen low. Polycondensa ion eac ions we e pe o med a 180 ºC o 8 h unde a 0.03-0.06 mba acuum. 1H NMR (300.1 MHz, CDCl3/TFA), δ (ppm): 8.1 (s, 4H, A H), 5.3 (s, 2H, OCH2O), 4.6 (m, 4H, OCH2CH), 4.5 (m, 2H, OCH2CH). 13C NMR (75.5 MHz, CDCl3/TFA), δ (ppm): 167.0 (CO), 133.5, 130.3, 95.7, 75.9, 64.9. MPPBxThxyT copolyes e s. The copolyes e s we e ob ained by a simila p ocedu e, wi h polyme iza ion condi ions sligh ly di e ing o each composi ion eed. MPPB96Thx4T. T anses e i ica ion eac ions we e pe o med a 160 ºC o 1 h, a 200 ºC o 1 h and a 240 ºC o 0.5 h unde a low ni ogen low. Polycondensa ion eac ions we e pe o med a 250 ºC o 2.5 h unde a 0.03-0.06 mba acuum. MPPB91Thx9T. T anses e i ica ion eac ions we e pe o med a 160 ºC o 1 h, a 200 ºC o 1 h and a 240 ºC o 0.5 h unde a low ni ogen low. Polycondensa ion eac ions we e pe o med a 240 ºC o 3 h unde a 0.03-0.06 mba acuum. MPPB84Thx16T and MPPB82Thx18T. T anses e i ica ion eac ions we e pe o med a 160 ºC o 1 h, a 200 ºC o 1 h and a 230 ºC o 0.5 h unde a low ni ogen low. Polycondensa ion eac ions we e pe o med a 230 ºC o 3.5 h unde a 0.03-0.06 mba acuum. MPPB77Thx23T and MPPB71Thx29T. T anses e i ica ion eac ions we e pe o med a 160 ºC o 1 h, a 200 ºC o 1 h and a 220 ºC o 0.5 h unde a low ni ogen low. Polycondensa ion eac ions we e pe o med a 220 ºC o 4 h unde a 0.03-0.06 mba acuum. NMR cha ac e iza ion o MPPBxThxyT copolyes e s. 1H NMR (300.1 MHz, CDCl3/TFA), δ (ppm): 8.1 (s, 4H, A H), 5.3 (s, y·2H, OCH2O), 4.6 (m, y·4H, OCH2CH), 4.5 ( , x·4H, OCH2CH2), 4.5 (m, y·2H, OCH2CH), 2.0 ( , x·4H, OCH2CH2). 13C NMR (75.5 MHz, CDCl3/TFA), δ (ppm): 168.0 (CO), 167.0 (CO), 134.2-133.2, 130.3, 130.1, 95.7, 75.9, 66.3, 64.9, 25.4. SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 307 6.3.2.3.2. Solid-s a e modi ica ion (SSM) o PBT Physical mix u es o pu i ied PBT (Mn= 23.3 kg·mol-1 and Mw= 47.1 kg·mol-1, de e mined by SEC), he cyclic diol Thx, and DBTO ca alys (0.36% mola wi h espec o PBT) we e p epa ed om solu ion, using a common sol en app oach as desc ibed elsewe e (La illa e al., 2013c -Subchap e 6.2-), in which he PBT was i s p ecipi a ed o emo e any i anium-based ca alys s. Di e en mola a ios o PBT and Thx we e used in o de o ob ain copolyes e s wi h a ying composi ions. The solid-s a e modi ica ion o PBT was pe o med in a eac o comp ising a glass ube (inne diame e = 2.4 cm) wi h a sin e ed glass i a he bo om. A hea exchange glass coil (inne diame e = 0.5 mm) su ounded he eac o and en e ed he inne glass ube a he bo om jus below he glass i . The ni ogen gas was hea ed by passing h ough his coil p io o en e ing he eac o , which was imme sed in an oil ba h kep a 160 ºC. The ni ogen low was con olled by a low-me e . Typically, 0.4 g o he PBT/Thx physical mix u e was placed on he sin e ed glass pla e. The powde was ixed in place by addi ion o glass pea ls (diame e = 2 mm) on op o he powde , and he eac o was pu ged wi h a ni ogen low o 0.5 L·min-1 du ing 30 min p io o he eac ion. Reac ions we e le o p oceed a 160 ºC unde a 0.5 L·min-1 ni ogen low un il he desi ed molecula weigh s we e a ained, which we e ollowed as unc ion o eac ion ime using SEC. Reac ion imes we e in he 4-20 h ange. A e comple ion o he eac ion, he eac o was g adually cooled down o oom empe a u e by emo ing he hea sou ce and by con inuing he pu ging o he eac o wi h ni ogen. Subsequen ly, he ob ained polyme was d ied unde acuum. The Thx copolyes e s ob ained ia SSM a e abb e ia ed as SSMPBxThxyT, whe e x and y a e he mole pe cen ages (mol-%) o 1,4-bu anediol and Thx, espec i ely, in he esul ing copolyes e . NMR cha ac e iza ion o SSMPBxThxyT copolyes e s. 1H NMR (300.1 MHz, CDCl3/TFA), δ (ppm): 8.1 (s, 4H, A H), 5.3 (s, y·2H, OCH2O), 4.6 (m, y·4H, OCH2CH), 4.5 ( , x·4H, OCH2CH2), 4.5 (m, y·2H, OCH2CH), 2.0 ( , x·4H, OCH2CH2). 13C NMR (75.5 MHz, CDCl3/TFA), δ (ppm): 168.0 (CO), 167.0 (CO), 134.2-133.2, 130.3, 130.1, 95.7, 75.9, 66.3, 64.9, 25.4. 6.3.2.4. Hyd oly ic deg ada ion p ocedu es Films o he hyd oly ic deg ada ion s udies on he (co)polyes e s we e p epa ed wi h a hickness o app ox. 200 µm by cas ing om solu ion (100 g·L-1) in a mix u e o chlo o o m and HFIP (5:1). The ilms we e cu in o disks wi h a diame e o 10 mm and a Chap e 6 308 weigh o 20 o 30 mg, which we e subsequen ly d ied unde acuum o cons an weigh . Fo he hyd oly ic deg ada ion, samples we e imme sed in ials con aining 10 mL o ci ic acid bu e (pH 2.0) a 80 ºC. A e incuba ion o a p ede e mined pe iod o ime, he samples we e insed ho oughly wi h dis illed wa e , d ied o cons an weigh and analyzed by SEC ch oma og aphy, NMR spec oscopy and SEM mic oscopy. Fo hyd oly ic deg ada ion s udies o he monome 2,3-di-O-me hylene-L- h ei ol, samples o his diol (80 mg) we e imme sed in NMR ubes con aining 1 mL o ci ic acid bu e (pH 2.0), sodium phospha e bu e (pH 7.4) o sodium ca bona e bu e (pH 10.5), all o hem p epa ed in D2O, and we e incuba ed a 80 ºC o 6 weeks. The esidue le a e incuba ion was analyzed by NMR spec oscopy. 6.3.3. Resul s and discussion 6.3.3.1. Polyme syn hesis The bio-based compound 2,3-di-O-me hylene-L- h ei ol (Thx) was p epa ed ollowing he ou e depic ed in Scheme 6.2. The pendan hyd oxyl g oups om na u ally occu ing L- a a ic acid we e p o ec ed by in e nal ace aliza ion leading o he o ma ion o a 1,3-dioxolane ing. The esul ing p oduc , dime hyl 2,3-di-O-me hylene-L- a a e, was subsequen ly educed o ob ain he desi ed Thx diol monome . This cyclic diol possesses a 2- old axis o symme y, and he e o e will p oduce s e eo egula polyme chains and i s wo p ima y hyd oxyl g oups a e expec ed o display he same eac i i ies owa ds a polycondensa ion eac ion. Scheme 6.2. P epa a ion o he bio-based 2,3-di-O-me hylene-L- h ei ol. SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 309 Thx was used as diol comonome in he syn hesis o he bio-based copolyes e s by wo di e en app oaches, iz. mel polycondensa ion (MP) and solid-s a e modi ica ion (SSM), as depic ed in Scheme 6.3. Scheme 6.3. P epa a ion o MPPBxThxyT and SSMPBxThxyT copolyes e s. MPPBxThxyT copolyes e s we e ob ained by eac ing dime hyl e eph hala e (DMT) wi h mix u es wi h a ying composi ions o Thx and 1,4-bu anediol in he mel . T anses e i ica ion eac ions we e ini ia ed a 160 ºC in o de o p e en ola iliza ion o he diols. As he eac ion p og essed he empe a u e was p og essi ely inc eased o a oid c ys alliza ion o oligome s. The subsequen polycondensa ion eac ions we e pe o med unde educed p essu e a empe a u es in he ange o 220-250 ºC. Lowe empe a u es and longe eac ion imes we e used o copolyes e s wi h highe Thx con en s, o a oid decomposi ion o his he mally sensi i e compound. Dibu yl in oxide (DBTO) was he ca alys o choice as eplacemen o he commonly used i anium (IV) e abu oxide (TBT). Resul s ob ained om he syn hesis o dime hyl 2,3:4,5-di-O- me hylene-galac a a e-based alipha ic polyes e s by mel polycondensa ion demons a ed he highe ac i i y o DBTO as ca alys compa ed o TBT (La illa e al., 2011 -Subchap e 3.2-). MPPBxThxyT copolyes e s we e ob ained wi h weigh a e age molecula weigh s be ween 39 and 43 kg·mol-1 and polydispe si y indices in he ange o 2.1-2.4 (Table 6.4). Besides he copolyes e s p epa ed by MP, solid-s a e modi ica ion (SSM) was used o p epa e copolyes e s wi h simila o e all chemical composi ions. Usually, SSM is pe o med a 20-30 ºC below he mel ing poin o a semic ys alline polyme (Jansen e al., 2005 and 2006; Gubbels e al., 2013b). Howe e , in his p esen s udy he SSM o poly(bu ylene e eph hala e) (PBT, Tm= 225 ºC) wi h he cyclic diol Thx was conduc ed a 160 ºC unde a ela i ely low ni ogen low, o minimize he ola iliza ion o he ca bohyd a e-based monome . DBTO was also used as ca alys o he SSM eac ions, because o i s high ac i i y in he low empe a u e SSM p ocesses (La illa e al., 2013c -Subchap e 6.2-). All he SSM eac ions we e moni o ed using size- exclusion ch oma og aphy (SEC) o ensu e ha he SSMPBxThxyT copolyes e s had simila molecula weigh s compa ed o hei MP coun e pa s, in o de o make a eliable Chap e 6 316 The DSC analysis e ealed ha he inco po a ion o Thx in o he backbone o PBT induced signi ican changes in he glass- ansi ion empe a u e (Tg) when compa ed o nea PBT (Table 6.5). The dependence o he Tg alues on he Thx con en is plo ed in Figu e 6.11. Rema kably, PThxT has a Tg alue 50 °C highe han PBT, p o ing a much mo e igid main chain s uc u e. Consequen ly, he pa ial eplacemen o he 1,4- bu anediol uni s by Thx esidues yields an inc ease in Tg, which shows no dependency on he copolyes e p epa a ion me hod (MP o SSM) . Figu e 6.11. Glass- ansi ion empe a u e e sus composi ion plo s o he MPPBxThxyT and he SSMPBxThxyT copolyes e s. The iangle ep esen s he Tg o he homopolyes e PBT. Mel ing empe a u es (Tm) and en halpies (ΔHm) we e measu ed by DSC and a e lis ed in Table 6.5. PBT is a semic ys alline polyes e wi h a mel ing empe a u e o 225 ºC. Copolyme iza ion o PBT wi h o he compounds commonly a ec s he he mal p ope ies signi ican ly. Endo he mic peaks, indica i e o he p esence o a c ys alline phase, we e obse ed o all MPPBxThxyT and SSMPBxThxyT copolyes e s, whe eas PThxT did no show such a beha io and p o es o be ully amo phous. The Tm o he copolyes e s p o ed o be dependen on he Thx con en and also on he p epa a ion me hod. Since in he i s hea ing un he samples p epa ed by MP o SSM ha e a di e en he mal his o y, he SSM samples being annealed du ing he SSM ea men , a compa a i e analysis o he Tm will be pe o med on he esul s ob ained om he second hea ing un, so a e c ys alliza ion om he mel (discussed below). Mel ing and c ys alliza ion en halpies o he MP and SSM copolyes e s, howe e , will be compa ed o i s hea ing, cooling and second hea ing. SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 317 F om DSC analysis o he ob ained copolyes e s i is clea ha he ma e ials p epa ed by SSM exhibi highe i s hea ing mel ing en halpies compa ed o hose p epa ed by MP exhibi ing a simila o e all chemical composi ion (Table 6.5). This highe en halpy is due o he segmen ed na u e o hese SSM-p epa ed copolyes e s and annealing o he copolyes e du ing he SSM eac ion. In o de o de e mine he c ys allini y o he Thx-based samples, o elucida e i co-c ys alliza ion had aken place and o complemen he DSC da a, wide-angle X- ay di ac ion (WAXD) was pe o med on he wo se ies o as syn hesized copolyes e s as well as on he PThxT and PBT homopolyes e s. The WAXD p o iles and he mos impo an B agg spacings p esen he ein a e shown Annex H. The pa e n o PBT is cha ac e ized by i e p ominen e lec ions a 5.6, 5.1, 4.3, 3.8 and 3.6 Å. Essen ially he same pa e n, in e ms o spacing and ela i e in ensi ies, is sha ed by all MPPBxThxyT and SSMPBxThxyT copolyes e s, e ealing ha he iclinic c ys al s uc u e o PBT (Hall, 1984) has been e ained and ha co-c ys alliza ion o ThxT epea uni s in he PBT c ys als does no occu . In ag eemen wi h DSC esul s, PThxT did no show any disc e e e lec ions cha ac e is ic o c ys alline ma e ial. The c ys allini y index o he ma e ials was es ima ed as he quo ien be ween he c ys alline and o al a ea o he X- ay di ac ion pa e ns (Annex H). A no iceable dec ease in c ys allini y wi h inc easing Thx con en was obse ed o he MP se ies, which was expec ed in iew o he lack o co-c ys allizabili y o he ThxT epea uni s wi h BT epea uni s. Rega ding SSMPBxThxyT copolyes e s, a sligh dec ease in c ys allini y was also obse ed du ing i s hea ing when he Thx con en was inc eased, indica ing ha he c ys alline phase was no comple ely e ained du ing he SSM p ocess. This phenomenon was obse ed be o e in o he copolyes e s p epa ed by SSM, and can be a ibu ed o he pa icipa ion o he ou e side o he PBT c ys alli es in ans- eac ions, he eby g adually dissol ing pa o he c ys alli es (Jansen e al., 2008; La illa e al., 2013c -Subchap e 6.2-). F om he da a p esen ed in Table 6.5, i can be no ed ha all he MPPBxThxyT and SSMPBxThxyT copolyes e s we e able o c ys allize om he mel , and ha he c ys alliza ion empe a u e (Tc) and he c ys alliza ion en halpy (ΔHc) bo h dec ease wi h inc easing Thx con en . Besides he ac ha Thx-based epea uni s canno (co)- c ys allize (see ea lie ), he inc easing amoun o s i e Thx con aining segmen s makes c ys alliza ion om he mel mo e di icul . Ne e heless, when he esul s o he MP se ies a e compa ed o hose ob ained o copolyes e s p epa ed by SSM a simila composi ions, he ma e ials ob ained by SSM showed highe Tc and ΔHc alues. This was expec ed, since longe PBT sequences a e p esen in he SSM-p epa ed copolyes e s, Chap e 6 318 which acili a e he c ys alliza ion o he ma e ials. A u he de ailed c ys alliza ion s udy will be desc ibed below. The he mal p ope ies ob ained om he second hea ing un o he MP- and SSM-p epa ed samples can be compa a i ely s udied since hey ha e simila he mal his o ies and ha e all been c ys allized om he mel . A e his mel -c ys alliza ion, MPPBxThxyT copolyes e s eco e ed abou 70-95% o hei ini ial c ys allini y and displayed no changes in hei mel ing empe a u es. Howe e , when he SSM copolyes e s we e c ys allized om he mel and ehea ed, he e was a de ini e change in hei mel ing beha io . Bo h he Tm and ΔHm dec eased signi ican ly when he i s and second hea ing we e compa ed. A eason o his di e ence is he (pa ial) andomiza ion o he chemical mic os uc u e by anses e i ica ion eac ions occu ing in he mel . This andomiza ion is an en opically d i en p ocess and is ca alyzed by he p esence o DBTO, which was added o he physical mix u es o acili a e he Thx inco po a ion. To s udy he andomiza ion phenomenon, samples o SSMPB82Thx18T we e kep in he mel a 250 °C o p ede e mined imes and a e his ea men hei chemical mic os uc u e and he mal p ope ies we e s udied using 13C NMR and DSC, espec i ely (Annex H). A dec ease o he mel ing empe a u e is obse ed as a unc ion o he ime du ing which he sample was kep in he mel , which was accompanied by an inc ease o he R- alue om 0.73 o 0.92, showing ha almos comple e andomiza ion o he chemical mic os uc u e occu ed a e long esidence imes a 250 °C. The e o e, he changes in he he mal beha io be ween he i s and second hea ing un a e caused by he (a leas pa ial) andomiza ion o he chemical mic os uc u e yielding sho e c ys allizable PBT sequences. When he Tm alues ob ained om he second hea ing uns o he copolyes e s p epa ed by SSM a e compa ed o hose p epa ed by MP, no iceable di e ences a e obse ed and an o e iew is gi en in Figu e 6.12. In e es ingly, bo h Tm and ΔHm eco ded du ing he second hea ing un o he samples p epa ed by SSM a e highe han hose measu ed o he MPPBxThxyT se ies, he highe mel ing poin s o he SSM samples being ela ed o he possible o ma ion o hicke lamellae om he longe PBT sequences. This implies ha e en hough andomiza ion o he blocky chemical mic os uc u e o he SSM-p epa ed copolyes e s does occu o some ex en du ing eco ding he DSC aces, i is no ye so ex ensi e as o yield ully andom copolyes e s o which only ela i ely hin lamellae wi h low mel ing poin s can be o med. SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 319 Figu e 6.12. O e iew o he mel ing empe a u e du ing he second hea ing un o he Thx-based copolyes e s p epa ed by MP and SSM. The iangle ep esen s he homopolyes e PBT. 6.3.3.4. Iso he mal c ys alliza ion As men ioned abo e, all he MPPBxThxyT and SSMPBxThxyT copolyes e s as well as PBT a e able o c ys allize om he mel . Since c ys alliza ion om he mel is ele an o p ocessing, he iso he mal c ys alliza ion o MPPB96Thx4T, MPPB91Thx9T, SSMPB96Thx4T, SSMPB91Thx9T and PBT we e compa a i ely s udied in he 195-205 ºC empe a u e in e al. All he polyes e ma e ials could be iso he mally c ys allized a 200 °C. The e olu ion o he ela i e c ys allini y, Xc, e sus c ys alliza ion ime is shown in Figu e 6.13. Figu e 6.13. Rela i e c ys allini y e sus ime plo o PBT, MPPB96Thx4T, MPPB91Thx9T, SSMPB96Thx4T and SSMPB91Thx9T iso he mally c ys allized a 200 ºC. Chap e 6 320 Da a ob ained om he iso he mal c ys alliza ion expe imen s a e displayed in Table 6.6. The obse ed onse and hal -c ys alliza ion imes, as well as he co esponding calcula ed A ami pa ame e s, a e gi en o each expe imen . I can be no ed ha o all he copolyes e s he A ami exponen n inc eases wi h empe a u e, he alues ob ained being in he 2.0-2.6 ange. The double-loga i hmic plo o hese da a indica ed ha only p ima y c ys alliza ion akes place in he selec ed ime in e al (Annex H). An inc ease in c ys alliza ion empe a u e yielded a delay in he onse o c ys alliza ion besides he dec ease in c ys alliza ion a e. Mo eo e , i was obse ed ha he p esence o mino amoun s o Thx no iceably dep essed he c ys allizabili y o PBT. Fu he mo e, he compa ison o c ys alliza ion da a o MPPB96Thx4T and SSMPB96Thx4T e idenced ha c ys allizabili y is mo e ep essed o a ully andom copolyes e p epa ed by MP han o he mo e blocky SSM-p epa ed copolyes e . In acco dance, SSMPB91Thx9T was ound o c ys allize a 200 ºC wi h a highe c ys alliza ion a e han he analogous MPPB91Thx9T copolyes e . The conclusion ha can be d awn om his compa a i e s udy is ha he p esence o Thx uni s dep esses he c ys allizabili y o e eph hala e-based polyes e s, and ha he c ys alliza ion a e depends on he chemical mic os uc u e o he polyme ic ma e ial. SSM allows o he p epa a ion o mo e eadily c ys allizable copolyes e s, since long PBT sequences a e e ained du ing he SSM p ocess. Table 6.6. Iso he mal c ys alliza ion da a. Copolyes e Tc 0 1/2 N -logk Tm (ºC) (min) (min) (ºC) PBT 200 0.19 0.82 2.14 -0.25 223.9 205 0.51 2.68 2.45 1.02 225.5 MPPB96Thx4T 195 0.41 4.82 2.56 1.77 210.0 200 0.55 12.77 2.61 2.99 212.1 MPPB91Thx9T 195 1.58 9.52 2.06 2.04 207.0 200 6.64 33.01 2.08 3.14 209.5 SSMPB96Thx4T 195 0.19 1.54 2.31 0.48 215.8 200 0.36 4.74 2.62 1.82 217.9 SSMPB91Thx9T 195 0.23 5.95 2.01 1.68 213.0 200 1.74 17.29 2.17 2.74 215.2 SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 321 6.3.3.5. Hyd oly ic deg ada ion To in es iga e he in luence o he inco po a ion o Thx on he hyd oly ic deg ada ion o PBT, a compa a i e s udy o he wo homopolyes e s PThxT and PBT in addi ion o he copolyes e s wi h 18% Thx p epa ed by MP and SSM was ca ied ou a pH 2.0 a 80 ºC. Unde hese condi ions, i is possible o s udy he deg ada ion in a easonable amoun o ime because o he ela i ely high hyd olysis a e. Changes in sample weigh and molecula weigh a inc easing incuba ion imes a e depic ed in Figu e 6.14. Figu e 6.14. Deg ada ion o PBT, MPPB82Thx18T, SSMPB82Thx18T and PThxT a pH 2.0 a 80 ºC. Remaining weigh (a) and molecula weigh (b) e sus ime. Chap e 6 322 PThxT unde wen a weigh loss o app ox. 16% a e six weeks o incuba ion ime, which was accompanied by a dec ease in he molecula weigh o abou 50%. This is in con as o PBT, because he la e did no show any weigh loss o signi ican dec ease in molecula weigh s unde hese condi ions. The dec ease in he sample weigh and he molecula weigh we e also no iceable o MPPB82Thx18T and SSMPB82Thx18T, e idencing he posi i e e ec o he Thx uni s on he hyd oly ic deg adabili y. Fu he mo e, SEM analysis showed mo e appa en physical deg ada ion o he su aces o MPPB82Thx18T, SSMPB82Thx18T and PThxT compa ed o PBT (Annex H). The dec eases in sample weigh and molecula weigh o he wo copolyes e s we e ound o be in e media e be ween hose o PBT and PThxT homopolyes e s, al hough he copolyes e s p epa ed by MP showed mo e ex ensi e hyd oly ic deg ada ion compa ed o he sample p epa ed by SSM. This can be explained by he highe c ys allini y o SSMPB82Thx18T compa ed o MPPB82Thx18T. The ela i ely long PBT sequences in he SSM sample do limi he deg ada ion. The mel ing en halpies o he ini ial SSM and MP samples ob ained by sol en cas ing we e 45.9 and 28.2 J·g-1, espec i ely. I is no ewo hy o men ion ha he mel ing en halpies o he emaining pa s o bo h he copolyes e s inc eased up o 59.3 and 46.6 J·g-1 a e 6 weeks o incuba ion, espec i ely. Such an inc ease in c ys allini y is indica i e ha hyd olysis has aken place p e e ably in he amo phous phase, as is usually obse ed in semic ys alline polyme s. Figu e 6.15. 1H NMR spec a in CDCl3/TFA o PThxT a e incuba ion a pH 2.0 a 80 ºC o 6 weeks ( op) and ini ial sample (bo om). SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 323 To gain insigh in o he deg ada ion mechanism o he polyes e chain a he molecula le el, 1H NMR spec a we e eco ded o he polyme esidues a e incuba ion (Figu e 6.15 and Annex H). The spec um o he esidue o PThxT displayed, in addi ion o he signals cha ac e is ic o he polyme , an inc ease in he signal a ising om CH2OH end g oups. This is indica i e o he educed molecula weigh , in ull ag eemen wi h da a p o ided by he SEC analysis. Fu he mo e, a ull s abili y o he cyclic Thx s uc u e agains hyd olysis can be in e ed om he o al absence o any signal indica i e o he hyd olysis o he ace al g oup in he MPPB82Thx18T, SSMPB82Thx18T and PThxT spec a. This esul is a he s iking because ace al g oups a e known o be sensi i e o acidic condi ions (Smi h and Ma ch, 2007), and he opening o he dioxolane ing migh be he e o e expec ed o happen o some ex en . To co obo a e he s abili y o he cyclic s uc u e agains hyd olysis, 2,3-di-O-me hylene-L- h ei ol was incuba ed in aqueous bu e a pH 2.0, 7.4 and 10.5 a 80 ºC o 6 weeks. The spec a eco ded a he end o he incuba ion pe iod a e shown in Annex H; all spec a co espond o he s uc u e o he o iginal diol wi hou any sign which would indica e hyd olysis o he ace al g oup aking place. 6.3.4. Conclusions The cyclic diol 2,3-di-O-me hylene-L- h ei ol (Thx), de i ed om na u ally occu ing a a ic acid, has been used as ca bohyd a e-based building block in he p epa a ion o poly(bu ylene e eph hala e) (PBT) copolyes e s. Two se ies o pa ially bio-based copolyes e s wi h compa able molecula weigh s we e p epa ed by ei he mel polycondensa ion (MP) o Thx wi h dime hyl e eph hala e and 1,4-bu anediol, o by he solid-s a e modi ica ion (SSM) o PBT wi h Thx. Copolyes e s wi h composi ions e y close o he eed a io and a andom chemical mic os uc u e we e ob ained by MP. Con e sely, SSM yielded only he pa ial inco po a ion o he Thx in he PBT backbone and led o a limi ed ange o composi ions. These copolyes e s had a block-like o e all chemical mic os uc u e, o med by PBT sequences p esen in he c ys alline phase du ing he SSM p ocess and a p ac ically andom amo phous phase, which is aking pa in he anses e i ica ion eac ions. Howe e , he blocky mic os uc u e o he copolyes e s p epa ed by SSM andomized a e p olonged imes in he mel . The inco po a ion o he cyclic bio-based Thx a o ded copolyes e s displaying a sa is ac o y he mal s abili y and exhibi ing inc eased Tg alues. Fu he mo e, he unique Chap e 6 324 block-like chemical mic os uc u e ob ained a e SSM yielded copolyes e s wi h ema kable he mal p ope ies. The SSM-p epa ed ma e ials showed be e c ys allizabili y om he mel because o he long PBT sequences p esen in he backbone o hese copolyes e s. Fu he mo e, hey displayed highe Tm alues and a highe c ys allini y compa ed o hei MP coun e pa s, al hough hese p ope ies we e no comple ely eco e ed a e c ys allizing om he mel as ound o he MP-p epa ed samples. The p esence o he Thx signi ican ly inc eased he hyd oly ic deg adabili y o PBT. This e ec was mo e p onounced o he ma e ials p epa ed by MP because o hei lowe c ys allini y. The deg ada ion o Thx-con aining polyes e s happened h ough hyd olysis o he main chain es e bonds wi hou al e a ion o he ace al s uc u e. 6.3.5. Re e ences Alla, A.; Rod íguez-Galán, A.; Muñoz-Gue a, S. Polyme 2000, 41, 6995-7002. Alla, A.; Oxelba k, J.; Rod íguez-Galán, A.; Muñoz-Gue a, S. Polyme 2005, 46, 2854- 2861. Blai , G.T.; DeF a ies, J.J. Hyd oxy Dica boxylic Acids. Ki k-O hme Encyclopedia o Chemical Technology, 2000. DOI: 10.1002/0471238961.0825041802120109.a01 Dhamaniya, S.; Jacob, J. Polyme 2010, 51, 5392-5399. Fenouillo , F.; Rousseau, A.; Colomines, G.; Sain -Loup, R.; Pascaul , J.P. P og. Polym. Sci. 2010, 35, 578-622. Galbis, J.A.; Ga cía-Ma ín, M.G. Suga s as Monome s. In: Belgacem, M.N.; Gandini, A.; Eds. Monome s, Polyme s and Composi es om Renewable Resou ces; Elsel ie : Ox o d, 2008, 89-114. Galbis, J.A.; Ga cía-Ma ín, M.G. Chem. Cu . Top. 2010, 295, 147-176. Gallucci, R.R.; Pa el, B.R. Poly(bu ylene e eph hala e). In: Schei s, J.; Long, T.E.; Eds. Mode n Polyes e s, Chemis y and Technology o Polyes e s and Copolyes e s; John Wiley & Sons: Chiches e , 2004, pp. 293-321. Gandini, A.; Coelho, D.; Gomes, M.; Reis, B.; Sil es e, A. J. Ma e . Chem. 2009, 19, 8656-8664. Gandini, A. G een Chem. 2011, 13, 1061-1083. Gómez, R.; Va ela, O. Mac omolecules 2009, 42, 8112-8117. SSM-p epa ed PBT copolyes e s om cyclic ace alized ca bohyd a e-based monome s 325 Gubbels, E.; Jasinska-Walc, L.; Koning, C. J. Polym. Sci., Polym.Chem. 2013, 51, 890- 898. (2013a) Gubbels, E.; Jasinska-Walc, L.; He mida Me ino, D.; Goossens, H.; Koning, C. Mac omolecules 2013, 46, 3975-3984. (2013b) Hall, I.H. The De e mina ion o he S uc u es o A oma ic Polyes e s om hei Wide- angle X-Ray Di ac ion Pa e ns. In: Hall, I,H.; Ed. S uc u e o C ys alline Polyme s; Elsel ie Applied Science: UK, 1984, pp. 39-78. Jansen, M.A.G.; Goossens, J.G.P.; de Wi , G.; Bailly, C.; Schick, C.; Koning, C.E. Mac omolecules 2005, 38, 10658-10666. Jansen, M.A.G.; Goossens, J.G.P.; de Wi , G.; Bailly, C.; Koning, C.E. Anal. Chim. Ac a 2006, 557, 19-30. Jansen, M.A.G.; Wu, L.H.; Goossens, J.G.P.; de Wi , G.; Bailly, C.; Koning, C.E; Po ale, G. J Polym. Sci., Polym. Chem. 2008, 46, 1203-1217. Japu, C.; Ma ínez de Ila duya, A.; Alla, A.; Muñoz-Gue a, S. Polyme 2013, 54, 1573- 1582. Kiely, D.E.; Chen, L.; Lin, T.-H. J. Am. Chem. Soc. 1994, 116, 571-578. Kiely, D.E.; Chen, L.; Lin, T.-H. J. Polym. Sci., Polym. Chem. 2000, 38, 594-603. Kin , D.P.R.; Wigs om, E.; Ma ínez de Ila duya, A.; Alla, A.; Muñoz-Gue a, S. J. Polym. Sci., Polym. Chem. 2001, 39, 3250-3262. K icheldo , H.R. Mak omol. Chem. 1978, 179, 2133-2143. K icheldo , H.R.; Behnken, G.; Sell, M. J. Mac omol. Sci. Pa A Pu e Appl. Chem. 2007, 44, 679–684. La illa, C.; Alla, A.; Ma ínez de Ila duya, A.; Beni o, E.; Ga cía-Ma ín, M.G.; Galbis, J.A.; Muñoz-Gue a, S. Biomac omolecules 2011, 12, 2642-2652. -Subchap e 3.2- La illa, C.; Muñoz-Gue a, S. Polym. Deg ad. S abil. 2012, 97, 1762-1771. -Subchap e 5.3- La illa, C.; Ma ínez de Ila duya, A.; Alla, A.; Muñoz-Gue a, S. Polym. Chem. 2013, 4, 282-289. (2013a) -Subchap e 4.3- La illa, C.; Alla, A.; Ma ínez de Ila duya, A.; Muñoz-Gue a, S. Biomac omolecules 2013, 14, 781-793. (2013b) -Subchap e 3.4- La illa, C.; Gubbels, E.; Ma ínez de Ila duya, A.; Noo do e , B.A.J.; Koning, C.E.; Muñoz-Gue a, S. Mac omolecules 2013, 46, 4335-4345. (2013c) -Subchap e 6.2- Li, W.D.; Zeng, J.B.; Lou, X.L.; Zhang, J.J.; Wang, Y.Z. Polym. Chem. 2012, 3, 1344- 1353. Lich en hale , F.W. Ca bohyd a es as O ganic Raw Ma e ials. Ullmann’s Encyclopedia o Indus ial Chemis y, 2010. DOI: 10.1002/14356007.n05_n07 Chap e 7 332 7.2.1. In oduc ion The u gen need o educe he amoun o pe oleum consumed in he indus y, as well as o minimize he impac o he use o plas ics on he en i onmen is a ac ing impo an e o s in esea ch by ollowing di e en app oaches. Thus, signi ican inc eases in he ecycling a es o polyme s a e aking place wi h acili ies and changes in ecen legisla ion ha now pe mi s e en ecycling o ood con ac polyme s (Wool and Sun, 2005; Welle, 2011; G ause e al., 2011). On he o he side subs i u ion o pe oleum- based monome s by hose coming om enewable sou ces has become one o he mos impo an challenges in cu en polyme esea ch (Belgacem and Gandini, 2008; Williams and Hillmye , 2008). Among he enewable na u ally occu ing sou ces, ca bohyd a es s and ou because hey a e hugely abundan , eadily a ailable and able o p o ide g ea unc ional di e si y; an inc easing ac i i y in he esea ch o ca bohyd a e-based polyme s is e lec ed in he ecen ly epo ed li e a u e (Galbis and Ga cía-Ma ín, 2008; Na ain, 2011; Gandini, 2011). A oma ic polyes e s, poly(e hylene e eph hala e) (PET) and poly(bu ylene e eph hala e) (PBT) in pa icula , a e high pe o mance he moplas ic ma e ials ha a e massi ely used in a wide di e si y o applica ions due o hei excellen mechanical and he mal p ope ies in addi ion o o he mo e speci ic ones. The high esis ance o a mosphe ic ac ion and biological agen s exhibi ed by hese ma e ials is an added alue when hey a e in ended o be used in long- e m applica ions. On he con a y, hey a e conside ed un iendly compounds when used in sho - e m applica ions because hei non- enewable o igin and g ea esis ance o deg ada ion (Mülle e al., 2001; Rych e e al., 2010). In his ega d, he de elopmen o a oma ic polyes e s om na u al sou ces is cu en ly d awing an eno mous in e es . To his pu pose a eally a ac i e app oach is o un old sus ainable p ocesses able o p oduce he adi ional monome s implied in hei syn hesis. Thus e hylene glycol can be p oduced ia oxida ion and subsequen hyd olysis o bio-based e hylene (Chen and Pa el, 2012), and 1,4-bu anediol by hyd ogena ion o succinic acid ob ained om co n (Delhomme e al., 2009); also he p oduc ion o e eph halic acid om limonene has been ecen ly pa en ed (Be i e al., 2010). Howe e he indus ial applica ion o hese me hods is s ill a om ealiza ion and monome s used oday o he syn hesis o indus ial a oma ic polyes e s a e almos en i ely p oduced om pe ochemical eeds ocks. Ano he possibili y o c ea ing sus ainable copolyme s o PET and PBT is eplacing ei he he diol o he diacid by o he bio-based monome s. This is an Cyclic ace alized aldi ols compa ed o isoso bide as comonome s o e eph hala e copolyes e s 333 ex emely appealing op ion p o ided ha he p ope ies o he o iginal polyme s a e imp o ed, o a leas no signi ican ly impo e ished. The high glass- ansi ion empe a u e (Tg) is a g ea ly app ecia ed p ope y in hose polyes e s add essed o packaging unde hea ing o o he manu ac u e o con aine s o p essu ized gaseous be e ages; copolyme iza ion wi h cyclic diols such as 1,4-cyclohexanedime hanol (Tu ne , 2004; González-Vidal e al., 2009) o 1,3- ciclobu anediol (Boo h e al., 2006) has been a common s a egy o ob ain a oma ic polyes e s wi h enhanced Tg. Ca bohyd a e-de i ed monome s wi h a cyclic s uc u e ha e achie ed a p i ileged posi ion because, in addi ion o hei na u al o igin, hey a e able o p o ide polyes e s wi h highe glass- ansi ion empe a u es while essen ially e aining hei o iginal pa e n o beha io . Thus, he olden known 2,5- u andica boxylic acid is ecei ing in hese las yea s a g ea deal o a en ion as a se ious al e na i e o eplace e eph halic acid in poly e eph hala es (Gandini e al., 2009; Gomes e al., 2011). A decade ago, he bicyclic anhyd ide 1,4:3,6-dianhyd o-D-gluci ol, known as isoso bide, eme ged wi h g ea pushing o ce as an adequa e monome o eplacing alipha ic diols in PET and PBT (S o beck and Ballau , 1996; K icheldo , 1997). Ve y ecen ly we ha e shown ha in e nally diace alized aldi ols wi h a bicyclic s uc u e a e also ca bohyd a e de i a i es e y sui able o p epa e a oma ic copolyes e s displaying sa is ac o y gene al p ope ies and enhanced Tg (La illa e al., 2012a -Subchap e 5.2-, 2012b -Subchap e 5.4- and 2013 -Subchap e 4.3-; Japu e al., 2012). Gi en he s uc u al p oximi y be ween isoso bide and diace alized aldi ols, as well as hei common po en ial use as polycondensa ion monome s, i is encou aging o make a compa a i e e alua ion o hei sui abili y o he syn hesis o a oma ic polyes e s. This pape has been hough wi h such aim and i epo s a compa a i e s udy o PBT polyes e s and copolyes e s ob ained by eplacing 1,4-bu anediol by 1,4:3,6-dianhyd o-D- gluci ol (Is), 2,3:4,5-di-O-me hylene-galac i ol (Galx), and 2,4:3,5-di-O-me hylene-D- manni ol (Manx). They will be called PBxIsyT, PBxGalxyT and PBxManxyT, whe e x and y s and o he mole pe cen ages (mol-%) o 1,4-bu anediol and suga -based bicyclic diol, espec i ely, in he esul ing copolyes e . The s udy examines he eac i i y o he h ee bicyclic diols in he polycondensa ion wi h dime hyl e eph hala e (DMT) unde he same polyme iza ion condi ions and makes a compa a i e e alua ion o he in luence ha each monome exe s on he glass- ansi ion empe a u e and c ys allini y o he polyes e s. Chap e 7 334 Compa ed s uc u e and p ope ies o Is, Galx and Manx 1,4:3,6-dianhyd o-D-gluci ol (Is) is he dianhyd ide gene a ed in he dehyd a ion o D-gluci ol (so bi ol). So bi ol is p epa ed by hyd ogena ion o D-glucose coming om ce eal s a ch. Is is he only bicyclic ca bohyd a e-based monome comme cially a ailable oday a indus ial le el (Fenouillo e al., 2010). I is composed o wo cis- used nea ly plana e ahyd o u an ings wi h a dihed al angle o 120º and he 2- and 5- hyd oxyl g oups in endo and exo posi ions, espec i ely. Since he wo hyd oxyl g oups o Is a e seconda y, hei accessibili y o eagen s is a he es ic ed, and due o hei di e en spa ial posi ion in he molecule hey will display di e en eac i i y; in ac , a de iciency o he eac i i y o he endo hyd oxyl g oup has been de ec ed in se e al polyme iza ion s udies ecen ly epo ed (Noo do e e al., 2006 and 2007; Fenouillo e al., 2010). 2,3:4,5-di-O-me hylene-galac i ol (Galx) is ob ained om galac a ic acid by ace aliza ion o he ou seconda y hyd oxyl g oups wi h pa a o maldehyde and subsequen educ ion. The s uc u e o Galx consis s o wo non- used 1,3-dioxolane ings wi h he wo p ima y hyd oxyl g oups in exo posi ions. Con a y o isoso bide, Galx is cen osymme ic so i s wo ee hyd oxyl g oups display he same eac i i y since hey a e spa ially undis inguishable. 2,4:3,5-di-O-me hylene-D-manni ol (Manx) is ob ained by ace aliza ion o 1,6-di-O-benzoyl-D-manni ol ollowed by hyd olysis o he benzoxy g oups. Manx consis s o wo used 1,3-dioxane ings and possesses a wo old axis o symme y and, simila ly o Galx, he wo p ima y hyd oxyl g oups a e in exo posi ions and display he same eac i i y. A compa a i e summa y o he main ea u es o Is, Galx and Manx o ele ance o his s udy is gi en in Table 7.1. Table 7.1. Main ea u es o bicyclic diols. Compound Is Galx Manx Chemical name 1,4:3,6-dianhyd o- D-gluci ol 2,3:4,5-di-O- me hylene-galac i ol 2,4:3,5-di-O- me hylene-D-manni ol Chemical s uc u e O O H HOH HO OH HO O O O O O O O O OH HO P o ec ing g oup dianhyd ide diace al diace al OH g oups seconda y p ima y p ima y Cycle s uc u e e ahyd o u an 1,3-dioxolane 1,3-dioxane Symme y 1 I C2 OH s e eo posi ions exo/endo exo/exo exo/exo Mel ing poin 60-63 ºC 100-102 ºC 139-140 ºC O igin D-glucose D-galac ose D- uc ose Cyclic ace alized aldi ols compa ed o isoso bide as comonome s o e eph hala e copolyes e s 335 7.2.2. Expe imen al sec ion The h ee se ies o polyes e s, PBxIsyT, PBxGalxyT and PBxManxyT, subjec ed he e o s udy we e ob ained acco ding o he syn hesis scheme depic ed in Scheme 7.1. Scheme 7.1. Polyme iza ion eac ions leading o PBxIsyT, PBxGalxyT and PBxManxyT copolyes e s. Fi e di e en copolyme iza ions, wi h mola eed a ios o 1,4-bu anediol o suga -based diol o 90:10, 80:20, 70:30, 60:40 and 50:50, we e ca ied ou o each bicyclic diol. Exac ly he same eac ion condi ions we e used o p epa e copolyes e s o di e en se ies wi h he same mola eed a io (1,4-bu anediol o suga -based diol) o he h ee se ies. Speci ic condi ions we e used o each mola eed a io, as hey a e de ailed in Annex I. The syn hesis and cha ac e iza ion o PBxGalxyT and PBxManxyT copolyes e s and hei pa en homopolyes e s has been epo ed p e iously in de ail (La illa e al., 2012a -Subchap e 5.2- and 2012b -Subchap e 5.4-). The syn hesis o he PBxIsyT amily has been ca ied ou now wi h he pu pose o p o iding he da a necessa y o he compa a i e s udy aimed in his wo k. The common syn he ic p ocedu e was he ollowing: The polyme iza ion eed was a mix u e o dime hyl e eph hala e, 1,4-bu anediol and he suga -based diol in he selec ed composi ions. A mola excess o diol mix u e o dime hyl e ep hala e was used, and dibu yl in oxide (DBTO) ca alys in 0.6% mola espec o monome s as well as an ioxidan s I ganox 1010 (0.1% w/w) and I ga os 126 (0.3% w/w) we e added. The eac ion was pe o med in he mel along wo s eps in a h ee-necked, cylind ical-bo om lask equipped wi h a mechanical s i e , a ni ogen inle and a acuum dis illa ion ou le . Fi s ly he anses e i ica ion eac ion was ca ied ou Chap e 7 336 unde a low ni ogen low a empe a u es in he 160-200 ºC ange depending on composi ion. The polycondensa ion eac ion was le o p oceed a a empe a u e be ween 210 and 240 ºC unde a 0.03-0.06 mba acuum. Then, he eac ion mix u e was cooled o oom empe a u e, and he a mosphe ic p essu e was eco e ed wi h ni ogen o p e en deg ada ion. The esul ing polyme s we e dissol ed in chlo o o m o in a mix u e o chlo o o m and i luo oace ic acid (9:1), and p ecipi a ed in excess o me hanol in o de o emo e un eac ed monome s and o med oligome s. Finally, he polyme was collec ed by il a ion, ex ensi ely washed wi h me hanol, and d ied unde acuum. The esul ing polyme s we e ex ensi ely cha ac e ized and hei he mal p ope ies accu a ely e alua ed in pa allel. The chemical cons i u ion, composi ion and mic os uc u e o polyes e s and copolyes e s we e de e mined by NMR and hei he mal s abili y measu ed by he mog a ime y unde ine a mosphe e. Thei mel ing and glass- ansi ion beha io we e examined by DSC and empe a u es and en halpies measu ed a hea ing using exac ly he same eco ding condi ions. The speci ic eac ion condi ions and esul s o he syn hesis o he h ee se ies o polyes e s as well as he echnical and me hodological de ails used in hei cha ac e iza ion and p ope ies e alua ion a e p o ided in Annex I. 7.2.3. Resul s and discussion 7.2.3.1. Syn hesis: Molecula weigh and composi ion The polyme iza ion condi ions used in he syn hesis o homopolyes e s and copolyes e s we e selec ed o imi a e as a as possible hose usually applied in he indus ial p ac ice; eac ions we e pe o med in he mel wi h o al absence o sol en s, and hey we e le o p oceed h ough a wo-s eps sequence o inc easing empe a u e and acuum. T anses e i ica ion eac ions we e s a ed a 160 ºC in o de o p e en ola iliza ion o diols, and le o p oceed o 2-3 hou s pe iod along which empe a u e was p og essi ely inc eased o a oid c ys alliza ion o ea ly o med oligome s. Polycondensa ion eac ions we e ca ied ou o 2-4 hou s a empe a u es in he 210-240 ºC ange and unde acuum o acili a e he emo al o ola ile by-p oduc s; lowe empe a u es and longe eac ion imes we e used o copolyes e s wi h highe con en s in suga -based monome s. An ioxidan s addi i e we e added in he syn hesis o PBxIsyT Cyclic ace alized aldi ols compa ed o isoso bide as comonome s o e eph hala e copolyes e s 337 copolyes e s o a oid discolo a ion, and dibu yl in oxide (DBTO) was he ca alys o choice o he h ee se ies ins ead o he commonly used i anium (IV) e abu oxide (TBT). Ou ea lie esul s in he syn hesis o alipha ic homopolyes e s om he bicyclic dies e dime hyl 2,3:4,5-di-O-me hylene-galac a a e and linea alkanediols demons a ed he highe ac i i y o DBTO ca alys compa ed o TBT which allowed o p oceed a lowe eac ion empe a u es wi hou inc easing eac ion imes (La illa e al., 2011 -Subchap e 3.2-). Unde so e eac ion condi ions, decomposi ion o he he mally-sensi i e suga compounds was minimized and highe molecula weigh s could be a ained. The syn hesis esul s ob ained o PBT, he h ee copolyes e se ies, PBxGalxyT, PBxManxyT and PBxIsyT, and hei espec i e pa en homopolyes e s PGalxT, PManxT and PIsT a e compa ed in Table 7.2. PBxGalxyT copolyes e s we e ob ained om 1,4-bu anediol, Galx and DMT wi h in insic iscosi ies o 0.7-0.9 dL·g-1 and weigh -a e age molecula weigh s be ween 36,000 and 41,000 g·mol-1 (La illa e al., 2012a -Subchap e 5.2-). Co espondingly, PBxManxyT copolyes e s we e ob ained when Manx was used as suga -based comonome ins ead (La illa e al., 2012b -Subchap e 5.4-). In his case, ela i ely high molecula weigh copolyme s we e also achie ed, wi h in insic iscosi ies be ween 0.8 and 1.2 dL·g-1 and weigh -a e age molecula weigh s con ined in he 38,000-52,000 g·mol-1 in e al. On he con a y, he esul s ob ained in he copolyme iza ions based on Is we e no as sa is ac o y as hose based on Galx and Manx; in insic iscosi ies and weigh -a e age molecula weigh s o PBxIsyT copolyes e s we e in he 0.3-0.4 dL·g-1 and 15,000-20,000 g·mol-1 in e als, espec i ely. Al hough polycondensa ions in bulk in ol ing Is ha e been usually ca ied ou wi h TBT as ca alys (Noo do e e al., 2006 and 2007; K icheldo e al., 2007; Inkinen e al., 2010); i was he e eplaced by DBTO by he easons indica ed abo e. The molecula weigh s epo ed o Is con aining copolyes e s ob ained by using TBT ca alys a e e en lowe han hose ob ained he e wi h DBTO. I is wo hy o no e ha molecula weigh alues a e e y simila wi hin each se ies (wi h he only excep ion o he homopolyes e en i ely made o suga -based diol), and ha essen ially he same molecula weigh dispe si y is ob ained o all he p epa ed polyes e s ega dless o which se ies is conce ned. This sa is ac o y ag eemen adds con idence o he compa a i e analysis o he mal p ope ies ha is ca ied ou below. 338 Table 7.2. Composi ion, molecula weigh s and he mal p ope ies o suga -based copolyes e s. Copolyes e Yield Mola composi ion XB/Xsuga Molecula weigh s The mal p ope ies (%) Feed Copolyes e a [η]b Mnc Mwc Ðc ºT5%d Tde Tg Tmg ΔHmg PBT 90 100/0 100/0 0.93 17,100 41,300 2.4 371 408 31 223 56.2 PB94Is6T 85 90/10 93.9/6.1 0.31 6,800 15,700 2.3 367 406 34 206 43.9 PB85Is15T 84 80/20 85.0/15.0 0.30 6,500 15,100 2.3 367 407 54 189 31.7 PB75Is25T 82 70/30 74.6/25.4 0.35 7,200 17,500 2.4 367 408 67 174 21.6 PB68Is32T 83 60/40 67.7/32.3 0.37 7,300 18,300 2.5 368 409 78 158 11.7 PB56Is44T 85 50/50 55.9/44.1 0.42 8,400 20,200 2.4 372 413 98 - - PIsT 80 0/100 0/100 0.20 2,300 5,400 2.3 374 424 148 - - PB89Galx11T 87 90/10 88.7/11.3 0.91 16,300 40,800 2.5 372 409 46 197 37.2 PB79Galx21T 89 80/20 78.9/21.1 0.90 16,800 40,300 2.4 373 411 53 179 26.1 PB69Galx31T 87 70/30 69.2/30.8 0.70 15,600 37,800 2.4 375 414 57 151 21.9 PB61Galx39T 88 60/40 61.3/38.7 0.65 14,400 36,500 2.5 377 417 62 138 14.8 PB51Galx49T 85 50/50 50.9/49.1 0.69 15,800 37,600 2.4 379 418 70 119 8.7 PGalxT 86 0/100 0/100 0.50 12,400 30,500 2.5 382 436 87 - - PB91Manx9T 86 90/10 91.0/9.0 1.18 20,300 51,200 2.5 371 408 55 197 34.1 PB80Manx20T 87 80/20 80.3/19.7 0.84 16,500 41,000 2.5 372 410 66 184 26.0 PB69Manx31T 86 70/30 69.2/30.8 0.75 16,600 38,500 2.3 374 411 77 162 5.5 PB59Manx41T 85 60/40 59.2/40.8 0.83 16,400 40,100 2.4 376 411 88 122 5.0 PB49Manx51T 88 50/50 49.0/51.0 0.77 16,300 38,900 2.4 377 412 100 - - PManxT 85 0/100 0/100 0.51 12,900 30,200 2.3 378 421 137 - - a Mola composi ion de e mined by in eg a ion o he 1H NMR spec a. b In insic iscosi y in dL·g-1 measu ed in dichlo oace ic acid a 25 ºC. c Numbe -a e age and weigh -a e age molecula weigh s in g·mol-1 and dispe si ies measu ed by GPC in HFIP agains PMMA s anda ds. d Tempe a u e a which 5% weigh loss was obse ed. eTempe a u e o maximum deg ada ion a e. Glass- ansi ion empe a u e aken as he in lec ion poin o he hea ing DSC aces o mel -quenched samples eco ded a 20 ºC·min-1. gMel ing empe a u e (Tm) and en halpy (ΔHm) measu ed by DSC a a hea ing a e o 10 ºC·min-1. Cyclic ace alized aldi ols compa ed o isoso bide as comonome s o e eph hala e copolyes e s 339 A de ailed compa ison o he Mw a ained o he h ee ypes o copolyes e s o simila con en s in he suga -based comonome is ep esen ed in Figu e 7.1. The lowe molecula weigh s a ained o PBxIsyT compa ed o PBxGalxyT and PBxManxyT when polyme ized unde he same polyme iza ion condi ions mus be a ibu ed o he lowe eac i i y o he seconda y hyd oxyl g oups o Is compa ed o ha o he p ima y ones p esen in bo h Galx and Manx. The limi ed eac i i y o Is in mel polycondensa ion has been p e iously epo ed (Noo do e e al., 2006 and 2007; K icheldo e al., 2007; Fenouillo e al., 2010). Isoso bide copolyes e s wi h highe molecula weigh a e achie able ia polycondensa ion in solu ion (K icheldo e al., 2007), bu due o he la ge use o sol en s, his me hod is no app op ia e o indus ial applica ion (F ade and Tessie , 2003). Recen ly, Sablong e al. in es iga ed he inco po a ion o isoso bide in o PBT ia solid-s a e polyme iza ion and epo ed he syn hesis o highe molecula weigh polyme s by his me hod (Sablong e al., 2008). Figu e 7.1. Weigh -a e age molecula weigh e sus composi ion plo o PBT copolyes e s con aining isoso bide (Is), 2,3:4,5-di-O-me hylene-galac i ol (Galx) and 2,4:3,5-di-O-me hylene-D- manni ol (Manx). The chemical cons i u ion and composi ion o he copolyes e s we e asce ained by NMR. A selec ion o spec a is p o ided in Annex I. The 1H NMR spec a co obo a ed he chemical s uc u e o he copolyes e s wi h all signals being p ope ly assigned o he di e en p o ons con ained in hei epea ing uni s. In eg a ion o he p o on signals a ising om 1,4-bu ylene and suga -based uni s led o quan i y he composi ion o he copolyes e s in such uni s. Fi e di e en expe iences, wi h mola eed a ios o 1,4- bu anediol and suga -based diol o 90:10, 80:20, 70:30, 60:40 and 50:50, we e ca ied Chap e 7 340 ou wi hin each se ies. The composi ions o he esul ing PBxIsyT, PBxGalxyT and PBxManxyT copolyes e s a e shown in Table 7.2. The co espondence be ween he comonome ic composi ion used in he eed and ha p esen in he esul ing copolyes e depended on which suga -based comonome was in ol ed. The ac ion (%) o suga - based diol (Is, Galx o Manx) ha is inco po a ed in he PBT copolyes e o he di e en eed composi ions ha ha e been s udied in his wo k a e depic ed in Figu e 7.2. The con en o he copolyes e s in Is uni s was ound o be in all cases signi ican ly lowe han in hei co esponding eeds, wi h losses o up o 40%; such disc epancy should be a ibu ed o he highe eac i i y o he hyd oxyl g oups o 1,4-bu anediol compa ed o hose o isoso bide. Con e sely, no no ewo hy di e ences in he ela i e inco po a ion o bicyclic ace alized diols and 1,4-bu anediol we e de ec ed, sugges ing ha he p ima y hyd oxyl g oups o bo h Galx and Manx a e able o eac a a a e simila o hose o 1,4- bu anediol. Fu he mo e, he eac i i y o he p ima y hyd oxyl g oups o Galx and Manx seems o be no a ec ed by he p esence o he neighbo ing ace alic cyclic s uc u e, nei he in he 2,3:4,5 no in he 2,4:3,5 a angemen , since bo h PBxGalxyT and PBxManxyT copolyes e s ha e composi ions e y close o hose o hei co esponding eeds. Figu e 7.2. F ac ion (%) o suga -based diol (Is, Galx o Manx) ha is inco po a ed in he PBT copolyes e o he di e en eed composi ions s udied in his wo k. Cyclic ace alized aldi ols compa ed o isoso bide as comonome s o e eph hala e copolyes e s 341 The 13C NMR spec a o PBxIsyT, PBxGalxyT and PBxManxyT copolyes e s show he non-p o ona ed a oma ic ca bon signal a 133-135 ppm wi h esolu ion enough (Figu e 7.3) o es ima e hei deg ee o andomness (Randal, 1977), leading o he conclusion ha he mic os uc u e was andom in he h ee se ies. Rega ding PBxIsyT copolyes e s, each ype o dyad consis s o mul iple peaks as a consequence o he wo o ien a ions possible o he non-symme ical Is uni . Con e sely, a single signal is de ec ed o e e y dyad in PBxGalxyT and PBxManxyT copolyes e s. Due o he symme y o Galx and Manx uni s, only one o ien a ion is easible o hese uni s when inco po a ed in he polyme chain. Consequen ly, copolyes e s made om Galx and Manx should be expec ed o be s e eo egula as i has been obse ed. Figu e 7.3. 13C NMR signals o he non-p o ona ed a oma ic ca bons o PBxIsyT (a), PBxGalxyT (b), and PBxManxyT (c) copolyes e s. The assigna ions co espond o e eph halic uni s a ached o: B, bu anediol; I, Isoso bide; G, Galx; M, Manx. 7.2.3.2. The mal p ope ies The he mal beha io o PBxIsyT, PBxGalxyT and PBxManxyT copolyes e s was sys ema ically s udied by TGA and DSC unde ine a mosphe e. The he mal pa ame e s esul ing om hese analyses a e gi en in Table 7.2, whe e he co esponding da a o he pa en homopolyes e s PBT, PIsT, PGalxT and PManxT a e also included o compa ison pu poses. The he mal decomposi ion o all hese polyes e s occu s in a single s age lea ing less han 10% o esidue upon hea ing a 600 ºC. PBT s a s o Chap e 7 348 349 GENERAL CONCLUSIONS  Cyclic ace alized alda ic acids and aldi ols de i ed om D-galac ose, D-mannose and L- a a ic acid wi h all he seconda y hyd oxyl g oups p o ec ed as me hylene ace als we e used o ob ain linea alipha ic and a oma ic polyes e s. Homopolyes e s and andom and block-like copolyes e s we e success ully p epa ed in high yields.  In mel polycondensa ion (MP) polyme iza ions as well as in solid-s a e modi ica ion (SSM) p ocedu es in ol ing hese suga -based cyclic monome s, he expe imen al condi ions we e ca e ully adap ed o he ola ili y o he suga -based compounds. Mild empe a u es we e used o homopolyes e s and copolyes e s wi h highe con en s in suga . The use o dibu yl in oxide (DBTO) ins ead o he commonly used i anium (IV) e abu oxide (TBT) as ca alys allowed o p oceed a lowe empe a u es wi hou inc easing eac ion imes, which led o a aining highe molecula weigh s. Thus, DBTO was chosen as ca alys in all he MP ca ied ou in his Thesis, and also was demons a ed o be e y ac i e in low empe a u e SSM p ocesses.  Alipha ic semic ys alline biodeg adable homopolyes e s om bicyclic ace alized dime hyl galac a a e and linea alkanediols, and om bicyclic ace alized D-manni ol and dime hyl succina e we e p epa ed in high yields wi h sa is ac o y molecula weigh s by polycondensa ion in he mel unde mild condi ions. Compa ed o he analogous alipha ic linea homopolyes e s poly(alkylene adipa e)s and poly(bu ylene succina e), he Tg was signi ican ly inc eased by he p esence o he bicyclic uni s in abou 50-100 ºC, eaching alues in he -17 o 6 ºC ange o he non- used bicyclic galac a a e ones, whe eas he used bicyclic manni ol allowed o ob ain a ully bio- based homopolyes e wi h Tg= 68 ºC. The mal s abili y and mechanical modulus we e no ably augmen ed as well.  When combined wi h linea alkanediols and dime hyl adipa e o dime hyl succina e by MP, he symme ic galac a a e-based and manni ol-based bicyclic uni s allowed o ob ain alipha ic semic ys alline andom copolyes e s wi h glass- ansi ion 350 empe a u es, he mal s abili y and mechanical pa ame e s in e media e be ween hose o he pa en homopolyes e s.  Random copolyes e s om poly(e hylene e eph hala e) (PET), poly(hexame hylene e eph hala e) (PHT) o poly(dodecame hylene e eph hala e) (PDT) wi h a ious cyclic ace alized monome s we e success ully p epa ed by MP o he whole ange o composi ions. As expec ed, hei p ope ies we e dependan on he alkanediol leng h and also on he s i ness o he cyclic uni inco po a ed. All PHT and PDT copolyes e s we e semic ys alline, and he a ia ion o Tm wi h composi ion did all in o a minimum o in e media e composi ions, acco ding o he exis ence o wo di e en c ys al s uc u es depending on which was he uni p edominan in he copolyes e . PET copolyes e s we e amo phous o con en s highe han 15% o suga -based uni s, and hei Tg, mechanical modulus and hyd odeg adabili y we e signi ican ly enhanced by he p esence o manni ol-based bicyclic uni s.  The e ec o he ca bohyd a e-based comonome on he mal and mechanical p ope ies o poly(bu ylene e eph hala e) (PBT) was opposi e acco ding o which uni , he diol o he diacid, was eplaced. The inco po a ion o ace alized dime hyl galac a a e by MP dec eased he he mal s abili y, he glass- ansi ion empe a u e and he mechanical moduli. On he con a y, hese pa ame e s we e inc eased when he alkanediol uni s we e he eplaced ones. The e ec o he p esence o cyclic aldi ol uni s on Tg and Tm o he esul ing andom copolyes e s was usually opposi e. They a o ed an inc ease in Tg due o hei s i e na u e, bu also ep essed pa ially he c ys allizabili y o he polyes e s and dec eased Tm. Since he he mal s abili y usually inc eased wi h he con en o cyclic aldi ols, a wide ange o empe a u es be ween mel ing and decomposi ion exis ed in he copolyes e s, allowing a mo e com o able mel p ocessing.  SSM-p epa ed PBT copolyes e s om cyclic ace alized aldi ols displayed a unique block-like chemical mic os uc u e, o med by long PBT sequences in he c ys alline phase and a p ac ically andom amo phous pa . A di e ence wi h isoso bide, which equi ed he p e ious syn hesis o a mac omonome , bicyclic ace alized aldi ols we e capable o being inco po a ed di ec ly in o PBT by SSM. The unique chemical mic os uc u e o he SSM-p epa ed copolyes e s endowed hem wi h supe io he mal p ope ies compa ed o hei andom coun e pa s p epa ed by MP. They displayed highe mel ing poin s, c ys alliza ion empe a u es and c ys allini y 351 al hough hese p ope ies we e diminished a e long imes in he mel due o he occu ence o andomiza ion p ocesses. Inco po a ion o he cyclic ace alized aldi ols by SSM led o aises in Tg compa able o hose o copolyes e s p epa ed by MP.  The p esence o cyclic ace alized suga -based uni s, bo h alda ic acids and aldi ols, enhanced signi ican ly he hyd odeg adabili y o alipha ic homopolyes e s and copolyes e s, and e en made a oma ic polyes e s suscep ible o wa e a ack. In all cases, hyd olysis ook place h ough he es e g oup wi hou modi ica ion o he diace al s uc u e. The cyclic me hylene ace al s uc u es we e esis an o hyd olysis in acidic, neu al o basic media. Deg ada ion o suga -based alipha ic polyes e s unde physiological condi ions was clea ly a o ed by he ac ion o enzymes. Fu he mo e, cyclic ace alized alda ic acids made a oma ic polyes e s suscep ible o biodeg ada ion whe eas his e ec was no de ec ed o he co esponding aldi ols.  Compa ed o isoso bide, bicyclic ace alized aldi ols showed a g ea e acili y o eac unde MP condi ions. This was due o he highe eac i i y o he p ima y hyd oxyl g oups o bicyclic ace alized galac i ol o D-manni ol compa ed o isoso bide. Mo eo e , a di e ence wi h isoso bide, he wo hyd oxyl g oups o hese bicyclic ace alized symme ic aldi ols displayed he same eac i i y.  As expec ed om i s cyclic s i na u e, he e ec o he used bicyclic ace alized D- manni ol on Tg o PBT was la gely g ea e han ha exe ed by he inco po a ion o acyclic suga uni s such as ime hoxy xyli ol o L-a abini ol. I had a much mo e p onounced e ec han he non- used bicyclic galac i ol, which was capable o aising he Tg o PBT by nea 30 ºC when i eplaced 1,4-bu anediol in a 40%. The e ec o he D-manni ol-based uni s u ned o be simila o ha o isoso bide; bo h PBT copolyes e s con aining 40% o ei he Manx o isoso bide inc eased he Tg by nea 60 ºC.  Isoso bide and bicyclic ace alized D-manni ol and galac i ol dep essed he c ys allini y o andom PBT copolyes e s in a deg ee ha depended on bo h symme y and s i ness o he bicyclic s uc u e; hey we e semic ys alline o con en s o up o 32%, 41% and 50% in hese uni s, espec i ely, whe eas he h ee 352 homopolyes e s en i ely made o suga -de i ed diols and e eph hala e uni s we e amo phous. 353 ANNEX A MONOMER SYNTHESIS Dime hyl 2,3:4,5-di-O-me hylene-galac a a e To a mix u e o 10.0 g o dime hyl galac a a e (42 mmol) and 10.0 g o pa a o maldehyde (332 mmol), 6 mL o sul u ic acid 96% we e added d opwise and he mix u e was se aside o 3 days a oom empe a u e. Me hanol (180 mL) was added and he mix u e was e luxed o 2 h. A e cooling, he solu ion was neu alized wi h ba ium ca bona e. Me hanol was emo ed unde educed p essu e and he whi e esidue was ex ac ed wi h chlo o o m. Remo al o chlo o o m ga e he c ude p oduc , which was ch oma og aphed on a silica gel column wi h e hyl ace a e-ligh pe oleum as eluan o gi e h ee ac ions. The i s ac ion, on ec ys alliza ion om e hyl ace a e-ligh pe oleum, yielded dime hyl 2,3:4,5-di-O-me hylene-galac a a e. Yield: 20% 2,3:4,5-di-O-me hylene-galac i ol Dime hyl 2,3:4,5-di-O-me hylene-galac a a e (560 mg, 2.1 mmol) was added o a suspension o li hium aluminium hyd ide (600 mg, 15.8 mmol) in d y e ahyd o u an (50 mL) and he mix u e was e luxed o 6 h. Excess o li ium aluminium hyd ide was des oyed by ca e ul addi ion o wa e o he cooled mix u e. The ino ganic ma e ial was il e ed o and he e ahyd o u an was emo ed unde educed p essu e o gi e he c ude p oduc , which was dissol ed in chlo o o m, d ied o e anhyd ous sodium sul a e and le o c ys allize. Rec ys alliza ion om chlo o o m yielded 2,3:4,5-di-O-me hylene- galac i ol. Yield: 70% 2,4:3,5-di-O-me hylene-D-manni ol 1,6-di-O-benzoyl-D-manni ol. A solu ion o 28.1 g o benzoyl chlo ide (200 mmol) in d y py idine (70 mL) was added d opwise o a dispe sion o 36.4 g o D-manni ol (200 mmol) [Document text truncated for crawler view.]