A method to improve the mechanical performance of styrene-butadiene rubber via vulcanization accelerator modified silica

Accelerator ethylenethiourea (ETU) was chemically grafted onto the surface of silane modified silica (m-silica) to obtain ETU-modified silica (silica-s-ETU). Silica-s-ETU could be homogeneously dispersed into the matrix of styrene-butadiene rubber (SBR) with fairly strong filler-rubber interaction and the grafted ETU molecules were still able to accelerate the sulfur vulcanization. Owing to the improved modification effect, the prepared SBR/silica-s-ETU nanocomposites showed more excellent mechanical properties than SBR/m-silica and SBR/silica nanocomposites containing equivalent accelerator component. Based on the results of immobilized polymer layer, the strengthening mechanism of silica-s-ETU was analyzed and substantiated. The highlight of this work lies in the fact that apparent improvement has been achieved by the surface modification of silica with vulcanization accelerator, which may open up new opportunities for the preparation of high performance rubber composites.