Report of chemical recycling processes

Grant Agreement number: 101058371 Project acronym: ESTELLA Project title: Design of biobased thermoset polymer with recycling capability by dynamic bonds for bio-composite manufacturing Grant Agreement number: 101058371 Project acronym: ESTELLA Project title: Design of biobased thermoset polymer with recycling capability by dynamic bonds for biocomposite manufacturing DELIVERABLE 4.4 Report of chemical recycling processes Contractual Date of Delivery: 31 August 2025 Actual Date of Delivery: 01 10 2025 Lead contractor for this deliverable: AND Author(s): Mª Dolores Ramírez Rodríguez, Mª Ángeles Fontecha, Irene Delgado María Schonher, Daniela Trambitas Participants(s): Andaltec (AND), FeyeCon (FEY) WP contributing to the deliverable: WP 4 Nature: Confidential Version V. 3 Grant Agreement 101058371 Project ESTELLA ESTELLA_D4.4_V3_QR_ICSO_AND ©ESTELLA - This is the property of ESTELLA Parties: shall not be distributed/reproduced without formal approval of ESTELLA General Assembly. contained therein. Executive Summary The objective of this task is to evaluate different chemical recycling strategies for bio-composites developed in the Estella project. Specifically, there are two types of strategies to be evaluated: chemical treatments (organic solvents and water at atmospheric pressure and medium pressure acid and base digestion, and catalytic and oxidative treatments) and recycling assisted with supercritical CO2. The composites used for solvolysis are the materials selected to develop the prototypes described in D3.3 (Manufacture of Bio-composite prototypes), prototypes, which ultimately use ICSO resin. In addition to these, FEY has conducted chemical recycling tests on composites developed with the NIC polymer base (NIC resin + NFC). The composites selected for the prototypes are ICSO + hemp (38%), ICSO + nanocellulose 1-1 (0.5%), ICSO + nanocellulose 1-1 (1%) and ICSO + nanocellulose 1-8 (0.5%). All materials appeared to be quite heterogeneous, so they were characterized using Fourier Transform Infrared Spectroscopy (FTIR) in order to subsequently compare their composition. All materials manufactured with ICSO resin are composed of an epoxybased vitrimer derived from fossil resources, designed to cross-link with carboxylic acids and/or anhydrides, forming network of dynamic covalent bonds (CAN). As mentioned in other deliverables as D4.1, the use of CAN provides the resin with improved recyclability and potential selfcuring behaviour. Solvolysis methods selected for the type of functional groups were used. The final composition of the resin was obtained by cross-linking the epoxy resin (BGEBA) with succinic anhydride in the presence of the Zn(AcAc)2 catalyst, as described in deliverable D3.2. FEY has used a variety of organic solvents, including alkaline, alkaline/alcohol, glycols, polyglycols, and amino. Figure 0 summarizes the entire experimental procedure followed in T4.4, which involved using the material manufactured at CID with ICSO resin to develop composites. The solubility of the matrices has improved in the procedures followed with and without the assistance of supercritical CO2 (scCO2), but the efficiency is limited. It was concluded in both ways that there is not clear advantage to methods using glycols as solvents.