Swelling pretreatment to promote the degradation of epoxy composites and retention of carbon fiber properties

With the increasing demand for lightweight materials, carbon fiber reinforced epoxy composites have seen rapid growth, leading to significant waste management challenges. The highly cross-linked epoxy matrix limits degradation efficiency, but swelling pretreatment enhances diffusion, accelerating degradation. However, concerns remain regarding volatile solvents, solvent selection and the effects on recovered carbon fibers. In this study, N-methyl-2-pyrrolidone, optimized using Hansen Solubility Parameters, was employed for swelling pretreatment. The results demonstrated a threefold increase in degradation efficiency while preserving carbon fiber strength from 91.8% to 98.6%. Furthermore, interfacial properties improved, which is crucial for broadening the applications of recycled carbon fibers. These findings highlight the potential of swelling pretreatment in facilitating efficient composite recycling while maintaining properties of carbon fiber, offering a promising route for high-value reuse.