Recyclable bio-based epoxy resins containing hybrid cross-linking networks

Abstract

Bio-based “thiol-epoxides” thermosets containing dynamic cross-linked network topologies, permanent cross-linking and recyclability have been successfully utilized in coatings, adhesives and composites. However, these materials typically have a low glass transition temperature and limited mechanical strength. Combining excellent mechanical properties with thermal properties remains a significant challenge. In this study, we developed a recyclable itaconic acid-based epoxy thermoset material with high glass transition temperature and tensile strength through thiol-olefin/thiol-epoxy click reaction and alkyl bond radical copolymerization to construct a hybrid cross-linked network. The tensile strength reached up to (105.9 MPa) while maintaining a high Tg (93.3°C), which is the highest value reported in the literature so far. In addition, the itaconic acid-based epoxy has excellent recyclable processing, self-healing properties, high hardness, solvent resistance, and surface bond strength as an adhesive and coating. The results hold potential applications in achieving sustainable development in coatings and adhesives.