Inverse vulcanization enabled self-motivated polysulfide silane: an ultra-efficient interfacial architecture for silica-filled elastomer hybrids

Incorporating sulfur-containing silane coupling agents (SSCAs) into silica-filled rubber composites is essential to improve the compatibility between silica and the rubber matrix. However, the synthesis of SSCAs requires multi-step processes and organic solvent usage, and the silanization efficiency is rather low. Herein, we presented the facile synthesis of a self-motivated polysulfide silane (PSTG) via one-pot sequential inverse vulcanization of sulfur, methoxy polyethylene glycol acrylate and triethoxyvinylsilane and utilized it as a new-brand interfacial modifier for rubber composites. The polyethylene glycol chains in PSTG direct its ethoxysilyl groups onto the silica surface via hydrogen bonds and subsequently promote the silanization reaction, and the polysulfide fragments couple with rubber chains during vulcanization. The interactions of PSTG with silica and hierarchical structures of the composites were comprehensively studied. The incorporation of PSTG greatly strengthens interfacial interactions and improves silica dispersion in rubber composites, resulting in remarkably high static mechanical properties and ultra-low hysteresis loss when compared to the most widely used SSCA bis[γ-(triethoxysilyl)propyl] tetrasulfide at the same ethoxysilyl group content.