White‐Light‐Mediated Imidazole Catalysis Toward Terpene‐Based Thermosets

Abstract

ABSTRACT Light‐mediated curing of terpene‐derived polymers generally depends on UV irradiation and photoinitiators. We report herein that environmentally friendly limonene‐ and carvone‐derived diepoxides cure with glutaric anhydride under white light through imidazole‐mediated catalysis, without conventional photoinitiators, to afford fully bio‐based thermosets. 1 H NMR reveals a switch in ring‐opening selectivity relative to thermal curing, from predominant exo ‐epoxide opening under heating to preferential endo ‐epoxide activation under white light, evidencing a distinct light‐responsive pathway. The resulting novel thermosets are colorless, transparent and exhibit enhanced thermomechanical properties over thermally cured counterparts, with a Tg of 110°C, tensile strength of 42 MPa, and strain at break of 15%. This strategy is underexplored in terpene‐derived epoxy–anhydride systems and may broaden the scope of terpene‐based thermoset networks.