ORGANIC POLYMER-SURFACE MODIFIED PRECIPITATED SILICA

To improve the performance of rubber compounds using precipitated sili ca as a reinforcing filler, the silica surface was directly modified b y (1) adsorption of a surfactant, (2) adsolubilization of an organic m onomer, (3) in situ polymerization of the monomer in the surfactant bi layer, and (4) partial surfactant removal. Silica was thus surface mod ified with polymerized styrene, isoprene, butadiene, and copolymers. S tyrene-butadiene modification afforded the most promising candidate ba sed on evaluation in a silica-filled model tire compound. Compound phy sical testing showed that cure times were decreased, and break strengt h, tear energy, elongation to break, and cut growth resistance were in creased. Thus, surface modification of silica by the in situ polymeriz ation of organic monomers affords unique materials useful in improving rubber cure properties and cured compound physical properties. (C) 19 95 John Wiley and Sons, Inc.