Upcycling woven carbon fiber prepreg scrap: Structure-property relationship and flexibility of platelets with stochastic meso-morphology

Upcycling of carbon fiber prepreg trim scraps resulting from ply cutting process offers both economic and environmental benefits, contributing to zero-waste goals. This study explored the upcycling of woven carbon fiber prepreg scraps using a high-precision ultrasonic ply cutting machine. The proposed method incorporated platelet cutting procedure into the ply cutting process, thus, transforming otherwise discarded material into material source for structural applications. The platelet cutting process preserved the integrity of the backing film, which facilitated handing of the upcycled trim scraps. The platelets were subsequently compression-molded into woven prepreg platelet-molded composites (WPPMC), and their mechanical behavior was assessed. The WPPMC specimens exhibited an ultimate tensile strength of 140.79 ± 16.55 MPa and modulus of 44.98 ± 4.26 GPa. The observed tight distribution of mechanical properties is attributed to the bi-directional properties of the weave and strain uniformity was observed using digital image correlation (DIC) during testing revealed that stress concentrations at the weave interlacing zones led to specimen failure. The proposed approach to trim scrap upcycling via high-rate ultrasonic cutting enables the production of complex shape composite structures, while significantly reducing industrial waste.