Reprocessable CO ₂ –Based Thermosets via Copolymerization of Elemental Sulfur with a δ-Lactone Derived from CO ₂ and Butadiene

3-Ethylidene-6-vinyltetrahydro-2H-pyran-2-one (EVP), a CO 2 -derived monomer featuring two C═C double bonds and a lactone ring, offers unique structural versatility. However, conventional vinyl addition polymerization of EVP typically yields all-carbon main-chain polymers with complex structures, hindering degradability and recyclability. Here, we harness the dual C═C bonds of EVP to directly copolymerize with elemental sulfur (S 8 ) via radical inverse vulcanization, establishing a new pathway for CO 2 -based polymer synthesis. Moreover, leveraging the distinct reactivities of the two C═C double bonds, EVP-derived monomers were prepared through selective Michael addition with dithiols or 6-mercapto-1-hexanol, enabling the fabrication of tunable CO 2 -based elastomers through copolymerization with S 8 . The resulting polymers incorporate dynamic S–S bonds, imparting intrinsic recyclability and self-healing properties. This study presents a versatile and efficient strategy for constructing sustainable CO 2 -based polymers via C═C double-bond addition chemistry of EVP.