Recycling of Carbon Fiber-Reinforced Epoxy Resin by Sustainable Solvolysis

The increasing demand for epoxy-based carbon fiber-reinforced plastics (CFRPs) has led to significant waste generation and environmental concerns. To address this issue, a novel, recycling method has been developed using a mixture of methyl ethyl ketone (MEK) and hydrogen peroxide (H₂O₂) as a solvent system. This approach selectively decomposes the epoxy resin matrix under mild conditions, recovering carbon fibers with minimal damage. Optimal conditions for resin decomposition were identified at 70 °C for 12 h with a liquid-solid ratio of 15 in a MEK/H₂O₂/H₂O molar ratio of 1/1/4, achieving a decomposition ratio of up to 95%. The recovered carbon fibers were used to create new composites, which showed similar tensile properties to those reinforced with virgin carbon fibers. The decomposed resin was characterized using Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC), revealing a broad distribution of low-molecular-weight compounds. This study demonstrates a promising approach for the recycling of carbon fiber-reinforced plastics (CFRPs), which can help reduce waste generation and promote cost effectiveness and sustainability in the manufacturing of these materials.