Preparation of hexamethyl disilazane-surface functionalized nano-silica by controlling surface chemistry and its “agglomeration-collapse” behavior in solution polymerized styrene butadiene rubber/butadiene rubber composites

A series of nano-silicas with varying content of grafted hexamethyl disilazane (HMDS) modifier were prepared by liquid phase in-situ surface modification method in combination with granulation technology. The effect of the as-prepared nano-silica as fillers on the mechanical properties and abrasion resistance of solution polymerized styrene butadiene rubber (SSBR)/butadiene rubber (BR)-matrix composites were investigated. It was found that the content of the surface hydroxyl of the as-prepared organic-inorganic hybrids, HMDS-capped nano-silica, can be well tuned by adjusting the modifier dosage. The resultant HMDS-capped nano-silica have greatly improved dispersibility in rubber matrix as well as highly enhanced compatibility and interfacial interaction with the rubber matrix, which is favorable for improving the mechanical properties and abrasion resistance of the SSBR/BR-matrix composites. Particularly, the SSBR/BR-matrix composite filled with HMDS-capped nano-silica obtained at a modifier dosage of 20% (mass fraction) exhibits greatly improved mechanical properties and wet skid resistance(12.0%) as well as significantly reduced rolling-resistance(30.4%) and Akron abrasion(18.4%) as compared with the one filled with unmodified nano-silica. The present approach, with good access to surface chemistry manipulation of nano-silica, could help to promote the application of functionalized nano-silica in tire industry.