Recycling of anhydride-cured epoxy resin-based carbon fiber-reinforced composites via a β-phenethyl alcohol/TBD catalytic system

Abstract

Carbon fiber-reinforced polymers (CFRPs) are widely applied due to their outstanding mechanical properties. However, the intrinsic difficulty in recycling their thermoset resin matrix has led to serious environmental pollution and resource waste, becoming a major bottleneck hindering the sustainable development of CFRPs. In this study, a green and efficient chemical recycling strategy was developed by constructing a synergistic catalytic system composed of β-phenylethanol and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), enabling the rapid degradation of anhydride-cured epoxy-based CFRPs under mild conditions (190 °C, atmospheric pressure). By optimizing the mass ratio of the catalyst to the composite material [TBD : CFRP (wt : wt) = 1 : 3.27], nearly complete resin degradation (>99%) was achieved within 2 hours. The reclaimed carbon fibers retained up to 93.2% of their original single-fiber tensile strength. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analyses confirmed that no significant deterioration occurred in the surface chemical functionalities or the degree of graphitization of the reclaimed fibers compared to the pristine ones. This work offers a simple, efficient, and environmentally friendly solution for the closed-loop recycling of thermoset-based CFRPs.