Joint hybridization of secondary fillers and polymers towards improved silica-reinforced NR tire tread compounds

To improve the properties of silica truck tire tread compounds, especially abrasion resistance, the effect of vinyl-contents in Butadiene Rubber (BR) or Solution Styrene Butadiene Rubber (SSBR) as secondary polymers in silica-filled Natural Rubber (NR) compounds at a ratio of 80/20 phr, is investigated in the first part. By increasing the vinyl-content in BR in combination with NR, a better Payne effect, 300% modulus, reinforcement index, tan delta at -20oC and 0oC are obtained, whereas tensile strength, elongation at break and DIN abrasion resistance index decrease with increasing vinyl-content. Increasing vinyl-contents in SSBR show improvements in Payne effect, 300% modulus, tan delta at -20oC and 0oC and a little in DIN abrasion resistance index. The combination of secondary filler and polymer in silica-filled NR are covered in the second part of the present study. Silica/Carbon Black (CB)-filled NR/BR and NR/SSBR, resp. silica/OrganoClay (OC)-filled NR/BR and NR/SSBR show positive effects on the scorch time, optimum cure time, with slightly changed Payne effect, tensile properties, tan delta at -20oC and 0oC, and DIN abrasion resistance as compared to the compound with CB N134. The use of OC shows enhancement in Payne effect and tan delta at 60oC, indicative of a reduced filler-filler network and consequently lower rolling resistance of the tire tread compound compared to the compound without OC.