RECOVERY AND REUSE OF CARBON FIBER FROM DECONSTRUCTED COMPOSITES WITH A DICYCLOPENTADIENE AND 2,3-DIHYDROFURAN COPOLYMER MATRIX

Improving the life cycle of composite materials begins with low-energy manufacturing to achieve useful mechanical properties and often ends with either disposal or recycling. Thermoset composite recycling techniques typically involve burying, burning, solvent soaking, chopping, or grinding with only a small fraction of recycled material being used in down-cycled products. These resource-intensive processes are primarily driven by the environmental robustness of the composite and the difficulty of separating the reinforcement from polymer matrix. Prior work has demonstrated that dicyclopentadiene (DCPD) copolymerized with a cleavable comonomer, 2,3-dihydrofuran (DHF), can be deconstructed in solution via DHF hydrolysis by hydrochloric acid (HCl) in cyclopentyl methyl ether (CPME). In this paper, we discuss the recovery and reuse of carbon fibers and fabrics from the deconstruction of composites having a copolymer matrix of poly(DCPD-co-DHF) which can be cured by frontal polymerization. We explore the kinetics of composite deconstruction as a function of comonomer concentration. Carbon fibers were successfully deconstructed, recovered, and reused in multiple composites without significant structural degradation observed. The surface properties of the recovered carbon fiber were analyzed by contact angle measurements and X-ray spectroscopy to confirm that the chemical composition of the fibers remains largely unaltered by the deconstruction process.