Recycling of carbon fibers in epoxy resin composites using supercritical 1-propanol

The effects of degradation temperature, reaction time and additive on the efficiency of the recovery of carbon fibers from their epoxy resin composites by supercritical 1-propanol were investigated. The recycled carbon fibers were characterized using SEM, TGA, XPS, contact angle measurements and single fiber tensile strength tests. Results indicated that the rate of decomposition of the resin increased, but the mechanical properties of the recycled fibers decreased slightly with temperature. The decomposition rate of the resin and tensile strength of the recycled carbon fibers decreased with reaction time. 1 wt% of KOH additive in 1-propanol improved the recovery efficiency significantly. When the KOH concentration was increased beyond 1 wt% there was no obvious increase in the decomposition rate and the mechanical properties of the recycled fibers became worse. There were slight changes in the surface chemistry of the recycled carbon fibers and their contact angle with epoxy resin. Supercritical 1-propanol is an excellent recycling technology for carbon fibers in epoxy resin composites.