Investigation of alignment and layup optimization of recycled carbon fiber mats on mechanical and electromagnetic shielding properties of composites

Abstract Excellent recycled carbon fiber (rCF) was obtained using a thermally activated oxide semiconductor process. An alignment device was manufactured based on wet‐laid technology. It was used to investigate the effect of various alignment nozzle parameters on the degree of alignment of rCF mats. The mechanical, electrical conductivity and EMI shielding properties of composites reinforced by rCF mats with different layup structures were analyzed. The results showed that the optimal alignment parameters for rCF aligned mats included a convex nozzle shape, a nozzle diameter of 3 mm, a nozzle channel length of 50 mm, a nozzle up‐and‐down diameter ratio of 7:1, a nozzle departure height of 20 mm. These settings achieved a preferential alignment degree (PAD) of 93.07%. The design of layup structures for rCF mats with optimized fiber alignment fully exploits the material's anisotropic characteristics. The rCF‐0/EP composite material exhibited the highest tensile strength (195.45 MPa), while the rCF‐04/EP composite material not only demonstrated the highest flexural strength (247.95 MPa) but also showed excellent electromagnetic interference (EMI) performance (47.97 dB). The results of the research laid a theoretical foundation and provides scientific guidance for high‐value reuse of rCF. Highlights Utilized rCF as a reinforcing material for CFRP composites. Preparation of rCF aligned mats with high PAD. Effect of different layup structures on rCF aligned mat reinforced composites. rCF aligned mats improve mechanical properties and EMI properties of composites.