A novel high-efficiency pyrolysis strategy for recycling carbon fibers and interface strengthening of carbon fibers reinforced epoxy resin composites

In response to the difficulties in recycling and degradation of carbon fiber reinforced epoxy resin (CF/ER) composites and the inability to recycle high-value carbon fibers, this study proposed a new high-efficiency pyrolysis method of CF/ER to achieve clean recycling of CF, evaluated the surface properties of recycled CF and its interfacial bonding properties and mechanical strength of recycled CF/ER composites, and summarized the high-efficiency pyrolysis mechanism of CF/ER according to the pyrolysis products. XRD and Raman indicated that the microcrystalline structure of the recycled CF was slightly damaged but the physical structure was basically maintained. FTIR, XPS, SEM showed that the oxygen-containing functional groups and the surface roughness of recycled CF increased, AFM showed that the interfacial layer between recycled CF and ER thickened, and the appropriately enlarged interfacial layer was conducive to the external stress transfer from the CF to the ER, and impeded the expansion of the microcracks. When the CF content is 2 %, 5 %, and 10 %, the change rates of tensile and flexural strengths of recycled CF/ER are between 8 % and 12 %. This paper provided a fast and sustainable recycling method for CF/ER composites, which had certain theoretical significance and engineering application potential.