Effect of Sonication on Efficiency of Silane-modified Silica in Rubber Compounds

Reinforcing fillers such as silica are often added to rubber to improve its properties and performance. Silica is highly used in tire tread compounds for its known effect on tire performances such as rolling resistance, traction, and wear. The problem of using silica as a reinforcing filler is its highly polar and hydrophilic surface that leads to both poor rubber-filler and strong filler-filler interactions, consequently silica surface should be modified. In this work, three precipitated silica were used in a SBR rubber compound: a) Unmodified silica, b) Commercially pretreated silica with silane (TESPT) and c) In-house pretreated silica with silane (TESPT) after Sonication. Compounds were prepared by mixing these silicas and other ingredients with Emulsion Styrene-Butadiene-Rubber (E-SBR) using internal mixer and two-roll-mill. To characterize treatment of silica and its dispersion in the rubber matrix, FTIR and SEM were employed. Cure properties are obtained using a rheometer. Mechanical properties were compared using uni-axial tension experiments. Results showed that both treatment methods were successful in providing proper dispersion of silica in SBR matrix. Mechanical behaviour of compounds showed a proper reinforcing effect for both types of used treated silica.