Enhancing interfacial interaction and mechanical properties of styrene-butadiene rubber composites via silica-supported vulcanization accelerator

To modify the filler surface and simultaneously elude issues related to the physical loss by migration of rubber additives, the concept of “supported rubber additives” was proposed and vulcanization accelerator 2-benzothiazolethiol (M) was chemically grafted onto the surface of silane modified silica (m-silica) to prepare silica-supported vulcanization accelerator (silica-s-M). Silica-s-M could be homogeneously dispersed into styrene-butadiene rubber (SBR). Besides, the interfacial interaction between silica-s-M and SBR was significantly enhanced, which was confirmed by the constrained rubber chains approaching the filler surface. Consequently, silica-s-M effectively reduced the activation energy of vulcanization and SBR/silica-s-M composites showed much better mechanical properties than SBR/m-silica and SBR/silica composites containing equivalent accelerator component. From this work, it is envisioned that this methodology for the surface treatment of silica to prepare supported accelerator may be extended for other nanofillers and functional rubber additives, which may be promising for the preparation of high-performance and functional rubber/nanofiller composites.