Performance analysis of recycled carbon fiber under recycling process parameters optimized using response surface methodology

Abstract

The recycling of high-performance carbon fiber from carbon fiber-reinforced polymer (CFRP) wastes have great economic value and environmental significance. Based on the principle of thermally activated oxide semiconductors, the resin matrix decomposition of process model was established by response surface methodology (RSM). The morphology, elements, functional groups and mechanical properties of recycled carbon fiber were investigated. The results indicated that the degradation was positively correlated with time and temperature, and the degree of influence was significant, the effect of O2 flow rate and concentration were not significant. The influence of process parameters on resin decomposition was as follows shown: temperature > time > O2 concentration > O2 flow rate. The actual degradation was 96.12 wt.% under temperature of 520°C, time of 23 min, O2 concentration of 80% and flow rate of 180 mL/min. The recycled carbon fiber (rCF) was compared with the original carbon fiber the surface roughness of rCF was increased, and without carbon deposition on the surface. The content of C element and C–C bond on the surface of rCF were significantly increased, and functional group of COOH was produced. The tensile strength of rCF was maintained above 99%, the Young’s modulus was maintained at 92%, and the interfacial shear strength was maintained at 85%.