Modification of silica surface for rubber reinforcement using a continuous admicellar polymerization system

Abstract

Use of silica in rubber compounds provides beneficial properties such as increase in tensile strength, modulus and resilience. The better compatibility between elastomer and silica has been achieved by admicellar polymerization. Currently, this process has been successfully performed only in a batch system, which is not feasible for industrial applications. In the present work, a continuous reactor for the admicellar polymerization was developed. Cetyltrimethylammonium bromide. Styrene and isoprene were used as a surfactant and co-monomers, respectively. Modification of silica surface reduced the BET surface area and increased the mean agglomerate particle size of all samples. Scanning electron micrographs showed the increase in the particle agglomeration as well as an apparent loss of small diameter particles. The Fourier transform infrared spectroscopes proved the existence of styrene and isoprene polymer on the modified silicas. Effects of co-monomers loading and retention time on the admicellar polymerization were also investigated. The results showed that the 5 g co-monomer per kilogram silica and 60 minutes polymerization time provided the largest amount of polymer on silica surface.