Nano-reinforcement of tire rubbers: silica-technology for natural rubber: exploring the infuence of non-rubber constituents on the natural rubber-silica system

Natural rubber is a renewable resource material with outstanding properties which offers significant advantages over its counterparts, the fossil-resource synthetic rubbers. In fact, a natural rubber tree is an efficient carbon dioxide sequester. Since natural rubber is a natural product, it is subject to seasonal variations. The reinforcement of silica in natural rubber for low rolling resistance truck tires is still a challenge. Hence, this thesis aims to understand the silica reinforcing mechanism in natural rubber compounds. In silica technology, the four essential elements which are: elastomer, silica, coupling agent and mixing conditions, need to be properly optimized to achieve a positive compromise between the tire properties. The controlled nano-scale coupling between rubber molecules and the silica surface via a silane coupling agent, is critical not to be disturbed by other surface-active agents. This work focuses on the role of non-rubber constituents, particularly proteins contained in the natural rubber, on silica-silica and silica-silane interactions. Many areas were investigated such as mixing temperature, morphology and dispersion of silica in the NR-silica system, as well as blending natural rubber with synthetic polybutadiene and polyisoprene to enhance silica and natural rubber interactions. The combination of silica technology with natural rubber will produce more environmentally-friendly tires and increase the usage of natural rubber as an eco-friendly elastomer.