Efficient recovery of carbon fibers from carbon fiber-reinforced polymers using direct discharge electrical pulses

Abstract Carbon fiber-reinforced polymers (CFRPs) are lightweight, high-strength composite materials that are widely used in various industries. However, recycling CFRPs remains a significant challenge because of the difficulty in separating carbon fibers (CFs) from the polymer matrix. This study compares two electrical pulse methods, namely direct discharge (DD) and electrohydraulic fragmentation (EHF), for the energy-efficient and precise recovery of CFs from CFRPs. The DD method involves the direct application of high-voltage pulses to the CFRPs, leveraging the Joule heat generation, thermal stress generation, and expansion force caused by plasma generation. In contrast, EHF is based on intensive shockwave impulses generated by high-voltage discharge plasmas along the interfaces of different materials. We examined the physical properties of the recovered CFs, namely their length, tensile strength, resin adhesion, and structural degradation, as well as the energy efficiency of the two methods in terms of CF separation. The results showed that DD is more effective for CF recovery, considering the preservation of long fibers with high strength and the separation of individual fibers without residual resin on the surface.