Effect of 3-Propionylthio-1-propyltrimethoxylsilane on Structure, Mechanical, and Dynamic Mechanical Properties of NR/Silica Composites

Blocked mercaptosilane possessing two functionally active end groups can chemically react with both silica and rubber leading to significant improvement in silica-filled vulcanizate products. The effect of the novel blocked mercaptosilane (3-propionylthio-1-propyltrimethoxylsilane) (called hereafter PXT) on the structure, mechanical, and dynamic mechanical properties of NR/silica composite were studied. Equilibrium swelling test and scanning electron microscope (SEM) indicate that PXT is able to enhance the crosslinking density of natural rubber (NR)/silica composites and the dispersion of silica in matrix. Mechanical measurement of properties show that PXT can strengthen the reinforcement of silica for NR vulcanizate. In the presence of PXT, the resistance to flex cracking, abrasion and dynamic compression fatigue, and heat build-up of NR/silica composites can be improved substantially. For the application of automotive tire, it also obtains high-skid resistance and low-rolling resistance simultaneously at 2 phr of the PXT concentration. POLYM. COMPOS., 30:955961, 2009. (C) 2009 Society of Plastics Engineers