Wet orientation technology of recycled short carbon fiber and analysis of its reinforcement performance

Despite carbon fiber/epoxy (CF/EP) composites have the characteristics of excellent mechanical properties, light weight and corrosion resistance, problems such as high cost and severe environmental impact of waste restrict their further applications. Most of the recycled carbon fibers (RCF) recovered by the existing methods are fluffy, short and entangled with each other, which limit its mechanical properties. To address this issue, a wet fiber orientation technology was proposed to reorient and arrange RCF with different lengths. An oriented fiber felt was obtained via this method and RCF/EP fabricate specimens were prepared by compression moulding. The orientation tensor in the 2D plane was applied to evaluate the preferential alignment degree (D_PA) of the fiber. The microstructure and properties of the composites were analyzed by SEM and mechanical tests, respectively. The results show that the increasing of RCF length leads to poor fiber orientation. The mechanical properties of the composites are improved with the increase of RCF length and D_PA. Compared with 2 mm RCF, the D_PA of 6 mm RCF decreases by about 11%, whereas the tensile strength and modulus, flexural strength and modulus of the reinforced resin matrix composites increase by 63.6%, 91.5%, 48.8% and 43.0%, respectively.