Epoxidation Functionalized Isobutylene Isoprene Rubber toward Green-curing Pathway and High-performance Composites

Epoxidation of the carbon-carbon double bonds on unsaturated rubber macromolecules can produce novel modified rubber species with special properties, and construct eco-friendly crosslinking pathway via the reaction of epoxide groups to solve the problems brought by conventional sulfur vulcanization system. In this contribution, a novel modified product of isobutylene isoprene rubber (IIR), epoxy-functionalized IIR (EIIR) was successfully prepared by in situ epoxidation technique for the first time, and the crosslinking of EIIR was achieved by the reaction of oxirane groups with maleic anhydride (MAH) without additional additives. The reaction conditions for preparing EIIR were optimized through systematic research on the epoxidation process. Under optimal condition, the degree of epoxidation of the rubber reached around 99% without side reactions. The obtained EIIR/carbon black composites cured by MAH had excellent mechanical properties comparable to those of IIR composites. More importantly, compared with IIR composites, the air-tightness of the EIIR composites was improved by about 50%, and the flexural fatigue life of first-level cracks and sixth-level cracks was increased by several times. The significant improvement of these properties is of great significance for the application safety and energy saving of IIR materials.