Improvement in the properties of silica-reinforced natural rubber with the sustainable interfacial modifier: Effect of molecular weight and content of interfacial modifier

Abstract

Silica is the most reinforcing filler for enhancing the rubber properties. However, the incompatibility of silica with non-polar rubber is the main problem for application. Therefore, the researchers attempted to use the several methods in order to solve the problem. In this work, the appropriated hydroxyl telechelic natural rubber (HTNR) was determined by varying molecular weights in the range of 2,000-3,000 g·mol^-1 and contents in the range of 4-16%w/w of silica content in order to enhance the rubber properties. It was found that the decrease in Payne effect and the improvement in cure characteristics of silica-reinforced NR were achieved by using HTNR. However, the incorporation of various molecular weights and contents of HTNR in rubber influenced C₁ (crosslink density determined by stress-strain measurement) in rubber, which related to rubber properties. The increasing in C₁ caused the increases in tensile strength and abrasion index and the decrease in heat build-up. The optimum properties of rubber with silica loading at 30 phr was achieved by adding 2,000 g·mol^-1 HTNR at a loading of 8%w/w of silica content. However, for silica-reinforced NR, TESPT provided better properties than HTNRs.