Closing the Loop for Epoxy Composites: Sustainable Routes for Chemical Recycling of Anhydride-Cured CFRPs

Carbon fiber-reinforced plastics (CFRPs) combine outstanding strength-to-weight and stiffness-to-weight ratios with long-term durability, enabling significant weight reduction, energy savings, and emission mitigation compared with conventional structural materials. Their rapidly increasing use in aerospace, mobility, infrastructure, and energy applications, however, raises critical challenges for end-of-life management. While mechanical, thermal, and chemical recycling routes for CFRPs have been widely investigated, comparative assessments often emphasize degradation efficiency or fiber recovery while giving limited attention to matrix chemistry and safety, health, and environmental (SHE) implications. This review focuses on the chemical recycling of anhydride-cured epoxy resin systems, which dominate many high-growth CFRP applications. The various solvolysis and depolymerization strategies are critically examined in terms of reaction conditions, targeted bond-cleavage pathways, and the chemical structure and reusability of the resulting degradation products. Unlike previous reviews, this work integrates mechanistic analysis of anhydride-cured epoxy degradation with a quantitative evaluation of the SHE profiles of solvents and co-reactants, enabling comparison of chemical recycling routes beyond process efficiency alone. By jointly addressing chemical performance, circularity potential, and safety considerations, this review provides a framework for assessing and guiding the development of more sustainable chemical recycling strategies for CFRP systems.