Making Carbon-Fiber Reinforced Epoxy-Amine Thermoset Composites More Circular through Chemical Recycling by Catalyzed Solvolysis

The use of carbon-fiber reinforced thermoset polymers (CFRPs) is continuously growing in a wide range of manufacturing sectors, particularly when high performance, lightweight design, and corrosion resistance are required. However, their multimaterial cross-linked structure hinders their recyclability, resulting in the extensive generation of heterogeneous wastes. Nowadays, the correct management of end-of-life (EoL) thermosetting composites remains an open and unsolved issue. In this respect, this work presents a chemical recycling process of a model CFRP from an epoxy-amine network, operated at atmospheric pressure, relatively low temperature (≤200 °C), and mild pH (4-5), allowed by the modification of a Lewis acid catalyst. This process leads to complete liberation of the reinforcing carbon fibers without dimensional alteration, with mechanical characteristics fully comparable to the corresponding virgin fibers, and with the formation of a reusable oligomeric fraction. The recovered components are successfully upcycled by fabricating second-generation CFRPs. Finally, the solvolysis process is validated on real EoL composite parts from aerospace and sports equipment products. This work proposes an economically feasible, safe, and scalable approach to efficiently recycle amine-cured epoxy-based CFRPs, with reusability of all fractions and minimization of any secondary waste generation.