Epoxy Vitrimers–Delignified Wood Composite with Weldability, Reprocessability, and Degradability

Abstract

The demand for renewable fiber-based epoxy composites is increasing rapidly as a sustainable alternative to conventional synthetic composites. However, limited attention has been directed toward the degradation and reprocessing of the epoxy resin matrix, which could further enhance the environmental benefits of natural fiber-reinforced epoxy composites. This study utilized delignified basswood as a porous template to in situ synthesize epoxy vitrimers based on dynamic ester exchange reactions through vacuum impregnation, successfully preparing a Wood/Epoxy Vitrimers Composite (WEPVC). Unlike traditional wood–epoxy resin composites, WEPVC demonstrated thermally activated topological rearrangement behavior at 180 °C, achieving thermal welding repair and three cycles of mechanical crushing and hot-press reprocessing. In ethylene glycol solution, the material could be completely degraded within 240 min to recycle both the wood template and resin oligomers. The composite simultaneously exhibited excellent mechanical properties (tensile strength 73.21 MPa), thermal stability (degradation onset temperature 273 °C), and water resistance (water contact angle 82°). These combined properties make the WEPVC developed in this study an environmentally friendly, cost-effective candidate for sustainable structural materials.