Robust-Bonding, Recyclable, and Biodegradable Biobased Epoxy Vitrimer Adhesives with l -Cystine Ionic Liquid

Abstract Conventional epoxy resins (EPs) often suffer from limited thermal stability, poor recyclability, and environmental hazards, posing significant challenges for the development of adhesives that are simultaneously strong, tough, recyclable, and broadly applicable. In this study, a biomass-derived cystine-based ionic liquid ([TBA]2[Cys]) was synthesized and employed as an active monomer in a ring-opening reaction with diglycidyl ether of bisphenol A (DGEBA) to prepare a series of vitrimers (DTCV). The resulting materials had excellent overall performance: a tensile strength of 43.25 MPa and a lap shear strength of up to 28.09 MPa on iron substrates. In addition, DTCV demonstrated remarkable thermal stability, chemical recyclability, and resistance to various media, including water, organic solvents, and acids/bases. Owing to its biodegradability under ambient conditions, this material addresses the inherent nondegradability of conventional epoxy resins. This work provides a simple, green strategy for designing high-performance, sustainable, and environmentally friendly biomass-based vitrimers.