Recycling carbon fiber-reinforced polymers by pyrolysis and reused to prepare short-cut fiber C/C composite

Abstract

A new idea of reusing carbon fiber recycled from carbon fiber-reinforced epoxy resin (CF/EP) composite to fabricate short-cut fiber C/C composite by moulding was proposed. The recycled carbon fiber (rCF) maintains comparable properties to virgin carbon fiber (vCF) except for a small amount of pyrolytic carbon attached to it. The wettability of rCF-furfural acetone resin (FA), vCF-FA and pyrolytic carbon-FA is nearly the same by sessile drop method. The obtained rCF was subsequently fabricated into C/C composite by moulding. The density of the prepared rCF C/C composite is 1.51 g·cm−3 which is slightly higher than that of vCF C/C composite of 1.48 g·cm−3. The flexural strength of rCF C/C composite is 34.2 MPa, which is slightly lower than that the vCF C/C composite of 38.8 MPa. However, the vCF C/C composite exhibits pseudo-ductile fracture behavior, while the rCF C/C composite presents a brittle fracture behavior after reaching the maximum value. The reason can be attributed to the cluster structure of rCF resulting in its dispersion lower than that of vCF. Destruction of cluster structure and dispersion of rCF are vital for improving the mechanical properties of short-cut rCF C/C composite.