Exploring the potential of waste carbon fiber reinforced epoxy for high‐performance electromagnetic interference shielding

Abstract The waste carbon fiber reinforced epoxy (WFRE) is difficult to recycle and high‐value reuse due to its irreversible cross‐linked structure. Currently, many recycling methods are flawed, rendering effective recycling unattainable and resulting in the waste of high‐value carbon fibers and increased environmental pollution. In this study, the production of high‐aspect‐ratio carbon fiber powder from WFRE was achieved through the application of solid‐state shear milling technology. The prepared EP/WFRE/CNT composites exhibited commendable mechanical properties and good electromagnetic interference (EMI SE) shielding efficiency, owing to the excellent dispersion and interfacial adhesion. The EMI SE value of EP/WFRE/CNT composites reached 21.9 dB, meeting the basic demand in the civil field. The flexural modulus of EP/WFRE/CNT composites reached 5914 MPa with the incorporation of 5 wt.% CNT. Moreover, the storage modulus of composite at 40°C increased from 2299 MPa for neat epoxy to 3006 MPa for composites. This research proposes a novel application of WFRE as good mechanical performance material for electromagnetic interference shielding, demonstrating the potential for commercial‐scale applications. Highlights Solid‐state shear milling can effectively peel epoxy resin. Solid‐state shear milling can preserve the high aspect ratio of carbon fiber. EP/WFRE/CNT has a flexural modulus of up to 5914.8 MPa. EP/WFRE/CNT has EMI SE that reaches 21.9 dB. CNT and carbon fiber synergistically formed conductive network.