Study on recycled carbon fiber obtained by thermal activated oxide semiconductor and mechanical properties of its reinforced polymer composites

Abstract Considering the types of carbon fiber reinforced polymer (CFRP) waste and the length of recycled carbon fiber (rCF), it is still a challenge to obtain high‐performance rCF and realize its high‐value reuse. In this paper, rCF was obtained by the thermal activated oxide semiconductor, and the effects of temperature and time on the resin decomposition rate of CFRP with different resin systems were analyzed. Three remanufacturing processes, namely wet fiber alignment (WFA), direct ink writing (DIW) and fused deposition modeling (FDM), were used to remanufacture rCF in millimeter and micron scale into recycled carbon fiber reinforced polymer (rCFRP) and the effects of rCF content on the mechanical properties of rCFRP were studied. The results showed that the optimal recycling parameter for EP‐EDA is 520°C, 45 min, and for EP‐MeTHPA and phenolic resin, the optimal recycling parameter is 520°C, 35 min. With the increase of rCF content, the tensile strength and modulus of WFA, DIW and FDM samples all increased to varying degrees. When the rCF content is 15 wt%, the tensile strength of WFA, DIW and FDM samples is increased by 355.6%, 68.4%, and 34.5%, respectively, compared with the corresponding pure resin samples. The mechanical properties of WFA, DIW and FDM samples are greatly different due to the rCF content, rCF length, interface bonding and alignment of rCF. This paper emphasizes the important effects of remanufacturing process, material composition and rCF content on the properties of rCFRP, and provides multiple ways for high‐value reuse of rCF. Highlights rCF obtained by thermal activated oxide semiconductor. Resin decomposition rate of CFRP waste with different resin systems. Multiple remanufacturing processes for rCF. Effects of rCF content and material composition on the properties of rCFRP.