Inverse Vulcanization Through Epoxide Chemistry: A Low Temperature Non-Olefin Route to Sulfur-Rich Polymer Networks

Inverse vulcanization represents an effective strategy for transforming surplus elemental sulfur into value-added polymeric materials; however, current approaches are largely restricted to olefin-based monomers and rely on high-temperature radical processes. Here, we establish an epoxide-enabled inverse vulcanization platform that expands sulfur-rich polymer formation beyond olefin chemistry under solvent-free, base-catalyzed conditions. Mechanistic studies confirm a nucleophilic ring-opening pathway in which sulfur is incorporated into the polymer backbone when catalyzed by base catalyst. By integrating bio-based epoxidized vegetable oils with elemental sulfur, sulfur-rich networks are constructed through a catalytically tunable ring-opening pathway, enabling controllable network formation. The resulting materials maintain high sulfur content while exhibiting tunable mechanical properties, shape memory behavior, and strong adhesion on stainless steel, with lap shear strengths adjustable up to 10 MPa. The combination of mild processing conditions, renewable monomer feedstocks, and robust structural performance demonstrates a controllable and energy-efficient route for advancing inverse vulcanization toward sustainable adhesive and functional material applications.