Recyclable carbon fibre composites enabled by cystine containing epoxy matrices

Recyclable composites are of industrial relevance and benefits the environment, which initiates research towards more sustainable solutions. In this study, a commercial epoxy thermoset, modified by a bio-based additive is used as an infusion resin making recyclable carbon fibre composites. The matrix fractionation process was investigated and optimized with respect to additive & solvent concentration, and temperature. Fully cured carbon reinforced composites were dismantled under the optimum condition and after drying, reinfused, and cured into a new composite, repeated three times on the same carbon fibre material. A decrease in fibre volume fraction and composite performance was found as a number of recyclings were performed. Finally, it was demonstrated that the recycled carbon fibre ply could be reshaped, infused, and cured and thus be applied in new components.