Study On Industrial Application Of Silica/SBR Prepared By Wet Compounding Method

Silica is a kind of reinforcing filler that do not depend on petroleum resources, replacing carbon black gradually and can be used in the tire industry widely. Adding silica into tread rubber can improve the wet skid resistance of the tire as well as lower the rolling resistance to make the tire fuel-efficient. There are lots of hydroxyl groups on silica surface, lead to a poor compatibility between silica and rubber matrix and a tendency to self-aggregate between silica particles, which further results in bad distribution and high temperature while mixing by traditional dry blending method. In this study, silica was modified by silane coupling agents in water phase, and then blended with styrene butadiene rubber (SBR) latex. After flocculation, modified silica was co-coagulated with SBR and silica/SBR masterbatch was obtained. There was almost no loss of silica during such process, and silica/SBR nanocomposite was prepared through this wet compounding method.First, the effect of silane coupling agent Si69,3-mercaptopropyl trimethoxysilane coupling agent KH590 and new coupling agent Si747 on the preparation of silica/SBR nanocomposites by traditional dry blending method was investigated. Because of its oil solubility, Si69 was unfitted in wet compounding method, so only KH590 and Si747 were used to modify silica and prepare silica/SBR nanocomposites by wet compounding method. From FTIR and other characterization, it was clear that Si747 had a better silica modification effect than that of KH590. Si747 had a higher grafting degree as well. When the dose of Si747 was up to 10%(e.g., every 100g silica powder was modified by lOg Si747), the modification effect was the best. But the rolling resistance of silica/SBR nanocomposite prepared with Si747 was a little bit high. Meanwhile, silica/SBR compound prepared with KH590 scorched easily, which was unsafe in industry. In the future research, KH590 and Si747 can be used together, adding both of them into silica water slurry to prepare masterbatch, or supplementing one of them on the two-roll mill, or adjusting their mass ratio, all of these can be new attempts to gain the best performance of silica/SBR nanocomposite by wet compounding method.Furthermore, the modification temperature while adding Si747 into silica water slurry was changed and its effect on the preparation of silica/SBR nanocomposite was investigated. It was confirmed that wet compounding method could be handled at room temperature, which simplified the preparation procedure. Compared to traditional dry blending method, the wet compounding method was time-saving, energy-efficient and environmentally friendly.Finally, the industrial application of wet compounding method operated at room temperature was discussed. Silica/SBR masterbatches with different silica contents were prepared by wet compounding method at room temperature, and the properties of silica/SBR nanocomposites with different silica contents were investigated as well. It was observed from AFM that silica could disperse at nano dimension and disperse homogeneously in rubber matrix, even with high silica loading. Meanwhile, masterbatches with high silica loading could be filled into other rubbers such as ESBR and SSBR, which meant an extensive application in industry.