Effects Of Silica Modified By Macromolecular Modifiers On The Properties Of Green Tire Tread

Now silica is the main reinforcing filler of green tire tread, and silane coupling agents are its most common modifier. However, there exist some drawbacks in the silica-silane . system, such as volatiles generated in the processing and poor long-term durability (especially long-term abrasion). Based on hydrogen bonding theory, the polar macromolecular (nitrile rubber and tea polyphenol) were used as silica modifier by the interaction with the hydroxyl groups of silica. As the supplement of the chemical interaction, the physical interaction can improve the long-term durability of tire tread by the open and re-build of physical bonding between rubber and silica. The effects of types, contents and modification processes of macromolecular modifiers on the properties of tire tread were discussed, and the aims are developing a kind of new efficient macromolecular modifiers.Firstly, nitrile rubber (NBR) was used as the modifier, and the effects of its types, contents, and modification process on the properties of tire tread were investigated. The results showed that NBR is an effective silica surface modifiers, by preventing the adsorption of accelerator, which dramatically increased the curing rate of the tread compounds. NBR increased the physio-mechanical properties of vulcanizates, and decreased the heat build-up. When the content of NBR was 8phr, the tire tread compounds possessed high abrasion resistance, high wet skid resistance and low rolling resistance.Secondly, the tea polyphenol (TP), having plenty of phenolic hydroxyl groups, was used as the modifier of silica. The effects of its contents and modification processes (modification solvent) were studied. The results showed that the both ethanol and cyclohexane were beneficial to the modification effects of silica, and the comprehensive physio-mechanical properties of the tread were improved greatly. When cyclohexane was used as solvent, the tread had higher physio-mechanical properties, abrasion resistance and lower heat build-up. When ethanol was used as solvent, the tread had higher wet skid resistance and low rolling resistance with TP being 2% of the silica content.Finally, the effects of TP on anti-aging properties of the tire tread were investigated. The results showed that TP effectively improved the anti-aging properties of the tread. The more the TP’content are, the better anti-aging properties is. In conclusion, TP is a kind of green, renewable, multifunctional rubber processing aids.