Thesis (M.Sc.)--Chulalongkorn University, 2003

Tread compounds from rubber blends with different natural rubber and styrene butadiene rubber ratio (100:0, 80:20, 70:30, 60:40, 30:70, 20:80) were prepared by melt-mixing process. The silica and carbon black mixture as reinforcing filler at different proportions (5:0, 4:1, 3:2, 2:3, 1:4, 0:5) was 30%wt blended in rubber compounds. The important physical properties for tread compound were investigated. As silica content increased, the % resilience increased and heat build up in the compound decreased. Thus, the lower rolling resistance and the reduction of fuel consumption could be obtained. However, the tensile strength, tear resistance, abrasion resistance and hardness decreased, they could also decrease the tire life. The effects of styrene butadiene rubber content on the physical properties of the compounds were also studied in this work. As SBR content increased, % resilience and tear resistance decreased and heat build up increased. Moreover, the vulcanization reaction takes longer time.