The improvements in properties of silica-filled natural rubber with stearyl alcohol: Rheometric and tensile properties

Abstract

The effects of the stearyl alcohol incorporation as a new rubber additive on rheometric and tensile properties of silica-filled natural rubber (NR) composites were investigated using a semi-efficient vulcanization system. The NR composite was filled with silica filler with a fixed loading, 30.0 parts per hundred rubber (phr). The stearyl alcohol was a fatty alcohol based on palm kernel oil and incorporated into the silica-filled NR composites at 1.0, 2.0, 3.0 and 4.0 phr. It was found that the incorporation of stearyl alcohol upturned the scorch time but reduced the cure time of silica-filled NR composites. It was also found that stearyl alcohol acted as an internal plasticizer which reduced the minimum torque and tensile modulus but upturned the elongation at break of silica-filled NR composites. The stearyl alcohol upturned the torque difference/crosslink density and tensile strength up to 2.0 phr of loading. The 2.0 phr of stearyl alcohol was the optimum loading. From the overall results could be concluded that the stearyl alcohol produced softer silica-filled NR composites with a higher tensile strength.