Improving carbon/carbon composites mechanical and thermal properties by the co‐carbonization of pre‐oxidized carbon fiber and pitch

Abstract

The interfacial cracks generated during the high-temperature carbonization process, caused by the mismatch of thermal shrinkage rate between the fiber and matrix, limit the huge application potential of C/C composites. In this study, pre-oxidized carbon fiber (OPF) prepared from pitch, as a reinforcement, was introduced into the pitch-based carbon matrix to realize the co-carbonization of OPF and pitch. The results showed that the mechanical and thermal properties of the OPF-reinforced C/C composites were significantly improved. The compressive strength and flexural strength were 136.97 and 46.71 MPa, respectively, both were about 2.5 times higher than those of pristine C/C composites. And OPF-C/Cs had a carbon residual of about 30% at 800 C, which was 2.8, 4.4, and 2.1 times higher than that of Pristine-C/Cs, CF-C/ Cs, and MCF-C/Cs, respectively. The rough surface and abundant active sites of OPF could promote the growth of the graphite microcrystalline structure, resulting in an excellent fiber/matrix interface. Moreover, the adaptive expansion of OPF occurred during the co-carbonization process with pitch, which inhibited the generation of cracks at the fiber/matrix interface. Owing to its excellent affinity with pitch, OPF is believed to have a wide range of promising applications in highperformance C/C composites that require high-temperature treatment.

A Mini-Review on Preparation of Functional Composite Fibers and Their Based Devices

“…We briefly present the methods for fiber's functionalization in Figure 1, which will obtain the composite fiber through functionalizing the original fiber. Carbonization is the thermal decomposition of pre-prepared fibers under high temperatures, which removes the unstable parts and gains high pure carbon-based composite fiber to enhance the electroconductivity, chemical stability, and mechanical strength [24]. Hydroxylation is a chemical reaction where hydroxyl groups are coated on the fibers' surface [25].…”