Recycling of carbon fiber with epoxy composites by chemical recycling for future perspective: a review

This review intends on chemical recycling of the carbon fiber-reinforced epoxy resin composites (CFREPs) for future applications. Many recycling methods were investigated such as chemical, solvolysis, glycolysis and hydrolysis. Mechanical recycling produces poor-quality carbon fibers (CFs) which exhibits short length and lower tensile modulus, whereas thermal recycling process, especially pyrolysis, gives fibers with char formation on the surface. Among them, the most promising is chemical recycling, as CFs can be recycled from CFREPs very easily and in most environmentally favorable conditions. Additionally, recent approach of chemical recycling with supercritical fluids in which no mechanical degradation occurs was also reviewed. It comes under green reaction media as they are easily available, less expensive, less toxic, soluble in different organic and inorganic compounds, and distillation process can be introduced to recycle afterward also. An economical approach of chemically recycling thermoset epoxy resin is also considered. Various greener approach methods of chemical recycling and its advantages over various other recycling processes were discussed in details, and finally structural and nonstructural applications of recycled carbon fibers are discussed.