THE EFFECT OF BIS(3-TRIETHOXYSILYLPROPYL)TETRASULFIDE ON SILICA REINFORCEMENT OF STYRENE-BUTADIENE RUBBER

Bis(3-triethoxysilylpropyl)tetrasulfide (TESPT) was found to affect th e curing characteristics and the physical properties of styrene-butadi ene (SBR) gum rubber and in situ silica-filled SBR vulcanizates. Silic a incorporated by the in situ, sol-gel reaction of tetraethoxysilane w ith TESPT showed a much higher reinforcing efficiency than did convent ional mechanical mixing and the in situ method without TESPT. The high er reinforcing efficiency is attributed to the formation of a silica-r ubber network, which also changed the dynamic mechanical behavior of t he SBR vulcanizates. Transmission electron microscopy observations sho wed in situ. silica incorporation of very fine particles in comparison to the sol-gel process without TESPT.