BETTER BALANCE OF SILICA-REINFORCED NATURAL RUBBER TIRE TREAD COMPOUND PROPERTIES BY THE USE OF MONTMORILLONITE WITH OPTIMUM SURFACE MODIFIER CONTENT

摘要

Reinforcement of silica in tire tread compounds is known to reduce hysteresis or energy loss, which leads to a production of energy-saving tires. Even though silica-silane technology has been well established, further development to enhance its performance is still needed. One of the approaches is to use hybrid or dual filler. The use of silica-organomodified montmorillonite (MMT) dual filler in the reinforcement of natural rubber (NR) truck tire tread compounds is investigated. The NR-MMT masterbatches were prepared by using the in situ organomodified and latex compounding method. Because the surface-modifying agent or surfactant is a key factor in determining the level of MMT dispersion in the rubber matrix, the effect of quaternary amine salt (Q) contents on mechanical and dynamic properties of NR tread compounds reinforced by silica-MMT was studied. The results revealed that MMT and Q can effectively reduce the filler-filler interaction and complex viscosity owing to a good dispersion of MMT and silica in the NR matrix and Q, which acts as a dispersing agent in addition to the silane coupling agent used in the compound, leading to improvement in tensile, abrasion resistance, and dynamic mechanical properties with an increasing amount of Q. Furthermore, at the optimum content of the surfactant used (36 wt%), the silica-MMT-reinforced NR exhibited improved tensile strength (+4%), wet grip, and rolling resistance, respectively, as indicated by loss tangent at 0 degrees C (+6%) and 60 degrees C (-15%), while maintaining a modulus at 300% strain and abrasion resistance as compared with the silica-NR reference compound. Such a dual-filler system demonstrates its potential use for tire treads with better performance.