Elucidating the role of clay-modifier on the properties of silica-and silica/nanoclay-reinforced natural rubber tire compounds

Organoclay (OC) is one of the potential secondary fillers to be applied in silica-reinforced rubber compounds for tire applications. Commercial OC contains a large proportion of surface modifier, i.e., dimethyl dihydrogenated tallow am-monium chloride (2HT) type, that has an influence on the compound properties. To elucidate the effect of 2HT on the properties of silica-Natural Rubber (NR) compounds, a silica-only system, silica/OC, and silica/montmorillonite (MMT)/2HT added in situ during mixing, were comparatively studied. Irrespective in which form 2HT is added, it has potential to further enhance the performance of silica-NR compounds. Incorporation of 2HT suppresses filler flocculation and improves process-ability. Overall, the silica-only filled compound shows better mechanical properties than the silica/clay dual filler systems. The use of a small amount (2.4–4.7 phr) of 2HT improves 300% modulus, tear strength and abrasion resistance. The silica/OC gives better mechanical properties than the silica/MMT/2HT. With the optimum content of 2HT, a higher tan δ at –20°C and lower tanδ at 60°C can be achieved, all showing the beneficial potential of utilization of the modifying agent to improve wet traction and rolling resistance of silica-based tire tread compounds.