A Research on the Utilization of Precipitating Silica Particles in Natural Rubber, Chloroprene Rubber and Styrene Butadiene Rubber

Utilizing Precipitating Silica Particles as Non-Black Filler in Rubber Vulcanizates

Abstract

Precipitated silica (PSi) suspensions were used for preparing silica/natural rubber (NR) masterbatches via a latex system. Then, both types of dried silica/NR masterbatch were mixed with other rubber chemicals on a two-roll mill. The results showed that well-dispersed FSi suspension could be prepared by either using the ultrasonic bath or agitator bead mill, while only the agitator bead mill could give well-dispersed PSi suspension. Also, the amount of silica loss in the masterbatches was clearly less than in silica-filled NR prepared by using a conventional method, and the color of the uncompounded FSi/NR masterbatches was lighter than that of the PSi/NR masterbatches. Additionally Precipitated silica is promising non-black filler for rubber vulcanizates.It can be used to replace carbon black partly in tyres to reduce the rolling resistance of tyres and hence to bring down the fuel consumption. However, silica is not compatible with the commonly used olefinic hydrocarbon rubbers and hence mixing and homogeneous distribution of silica in rubber is difficult. Coupling agents are often necessary for proper binding of rubber and silica. Coupling agents facilitates filler incorporation and enhances the properties of the final product. The coupling agents also improve the processing behaviour by reducing the specific surface energy and the solubility parameter of the silica.