Dynamic-Mechanical Properties of Fumed Nanosilica-SBR Composites Prepared by a New Strategy in Melt Mixing

In recent years, silica has replaced carbon black in tire tread compounds. Better fuel economy through reduced rolling resistance, increased tread life, comparable or better traction for safety and a competitive cost, price structure; all of which lead to growing interest in silicareinforced rubber compounds. Most common silica filler used in rubber industry is micronsized precipitated silica. Fumed silica is composed of quite uniform nano-sized spheres. Virgin fumed silica is very fine and light dusty powder and its mixing by common mixers is not practical. Problems in melt mixing of fumed silica limits application of it in rubber industry. To study the effect of nano silica on dynamical- mechanical properties of nano silica- SBR composites, untreated fumed silica with high surface area was selected and mixedwith water to prepare silica gel. Prepared silica gel was dried in an oven at 110 ºC andvacuum oven at 80 ºC. Granulated fumed silica was obtained and mixed with SBR using melt mixing method. Vulcanization characteristics, mechanical and viscoelastic behavior of thecomposites was studied with reference to silica loading, using ODR Rheometer, uniaxialtension, and dynamical-mechanical-thermal analyzer (DMTA). Minimum and maximum torques of samples increases at higher silica loading. This shows the reinforcing effect ofthese fillers in the rubber compounds. Optimum cure times increases at low silica loading but it increases at higher silica loading. It was observed that stress and elongation at break isremarkably increased at higher silica loading. Increasing of modulus at higher silica loading isless than growth of stress and elongation at break at higher silica loading. Fumed-silica decreases the amplitude of peak loss factor that indicates polymer absorption andimmobilization on silica particles.

کلیدواژه ها:

SBR ، Nano ، Silica ، Viscoelastic