Two advanced styrene-butadiene/polybutadiene rubber blends filled with a silanized silica nanofiller for potential use in passenger car tire tread compound

Styrene-butadiene rubber (SBR) and poly- butadiene rubber (BR) were mixed together (75:25 by mass) to produce two SBR/BR blends. The blends were re- inforced with a precipitated amorphous white silica nano- filler the surfaces of which were pretreated with bis(3- triethoxysilylpropyl)-tetrasulfide (TESPT). TESPT is a sul- fur-bearing bifunctional organosilane that chemically bonds silica to rubber. The rubbers were primarily cured by using sulfur in TESPT and the cure was optimized by adding non-sulfur donor and sulfur donor accelerators and zinc oxide. The hardness, Young’s modulus, modulus at different strain amplitudes, tensile strength, elongation at break, stored energy density at break, tear strength, cyclic fatigue life, heat build-up, abrasion resistance, glass transition temperature, bound rubber and tan d of the cured blends were measured. The blend which was cured with the non-sulfur donor accelerator and zinc oxide had superior tensile strength, elongation at break, stored energy density at break and modulus at different strain amplitudes. It also possessed a lower heat build-up, a higher abrasion resistance and a higher tan d at low tem- peratures to obtain high-skid resistance and ice and wet- grip. Optimizing the chemical bonding between the rubber and filler reduced the amount of the chemical curatives by approximately 58% by weight for passenger car tire tread. This helped to improve health and safety at work and reduce damage to the environment.