Improving performance of natural rubber composites through the novel silica modified by a crosslinking agent

Silica dispersion and silica–natural rubber (NR) interaction are two major issues in determining the performance of a NR/silica composite in tire industry. In our research, the reaction product of 3-isocyanatopropyltrimethoxysilane and a crosslinking agent, poly( tert -butylphenol) disulphide, was used to modify silica. Then, the modified silica was added into NR by mechanical blending. The modification of silica can promote the silica dispersion and enhance silica–NR interaction. At silica loading of 50 phr, compared with the NR/pure silica composite containing 5 phr bis -( γ -triethoxysilylpropyl)-tetrasulfide, the NR/modified silica composite exhibits 18% shorter curing time, 16% higher 300% modulus, 9% higher crosslink density and 6% lower rolling resistance with comparable abrasion resistance even reducing the amount of silane coupling agent to 2 phr. This modification of silica by using the derivative of poly( tert -butylphenol) disulphide provides a novel approach to the preparation of the high-performance NR/silica composites and the reduction of the amount of bis -( γ -triethoxysilylpropyl)-tetrasulfide in tire tread formulations.