An Efficient Method of Recycling of CFRP Waste Using Peracetic Acid

We report a one-step oxidative method for the recycling of carbon fiber-reinforced polymer (CFRP) composite waste and the recovery of carbon fiber and the epoxy resin by treatment with peracetic acid (PAA) formed in situ from a mixture of acetic acid and hydrogen peroxide. The surfaces of the recovered carbon fibers were clean, and the tensile strength was comparable to that of the virgin fibers. A higher resin decomposition ratio of 97% could be achieved for the epoxy matrix under mild reaction conditions in comparison to other chemical recycling processes. ATR-FTIR, MALDI/TOF-MS, GPC, GC-MS, H-1 NMR, and Pyro-GC/MS analyses showed the formation of low molecular weight oxidation products of amine-cured epoxy resin along with high molecular weight compounds of high viscosity. A possible reaction mechanism for the degradation of the epoxy matrix is proposed. All the solvents used were recovered in pure and reusable form with more than 90% recovery efficiency. The recovered epoxy was reused along with an adhesive grade epoxy (2 wt %) with no significant loss of tensile strength. Almost complete recovery of the recycled products as well as the solvent along with no gaseous emissions and mild reaction conditions make this process more environmentally friendly.