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, quantitative relationship model between the decomposition rate of the resin-matrix and the process parameters was established. The morphology, elements, functional groups and mechanical properties of recycled carbon fiber(rCF) were analyzed under the optimal process parameters. The results indicated that the decomposition rate of resin 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 each factor indicates showed that temperature > time > O2 concentration > O2 flow rate. The actual decomposition rate of resin was 96.12% under temperature of 520 ℃, time of 23 min, O2 concentration of 80% and flow rate of 180 mL/min. Compared with the original carbon fiber(oCF), the surface roughness of recycled carbon fiber was increased, and there was no carbon deposition residue on the surface. The content of C element and C—C bond on the surface of rCF increased significantly, and functional group of COOH was produced, the graphite structure on the surface of carbon atomic surface change was not significant. 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%.