Utilization of composite ZnO in SBR/BR compounds and its effect on the cure and physicomechanical properties

Abstract

Zinc complexes have a considerable impact on human health and the environment, especially on aquatic wildlife. One of the primary sources of zinc release to the environment is worn rubber particles from tires. The environmental footprint of zinc oxide (ZnO) during production, use, and landfilling has prompted researchers to reduce its use in rubber formulations due to ecological and economic concerns. In this study, composite ZnO materials where ZnO particles are coated on precipitated calcium carbonate (CaCO3) are used in styrene butadiene rubber/butadiene rubber (SBR/BR) compounds, and their performance is compared with white seal ZnO and active ZnO. Trial compounds are prepared on a laboratory scale using composite ZnO materials with ZnO:CaCO3 ratios of 40:60, 60:40, and 90:10, and control compounds with white seal and active ZnO. All compounds are tested to evaluate their curing and physico-mechanical properties. It is observed that the surface area of ZnO plays an essential role in crosslink density and, hence, compound performance. Trial materials have no negative effect on the curing and mechanical properties of the compounds. Thus, it is concluded that composite ZnO materials can be used as alternatives to both white seal ZnO and active ZnO. They have environmental and economic advantages due to their lower ZnO content. The compound recipe has the potential to be used for tire tread compounds.

Keywords

• crosslinking agent
• tensile testing
• rubber
• curing
• hardness