Filler Effects on Temperature Dependence of Viscoelastic Properties of Filled Rubbers

Measurements of storage and loss moduli G′ and G″ in linear viscoelasticity have been made on SBR SL-574 containing 50 phr N330 carbon black, silica AQ with coupling agent, and silica AQ, both cured and uncured, and compared with similar measurements on the cured and uncured gum rubbers. The rage of temperature was −60 to 70°C, and of frequency 0.4 to 100 rad s−1. The cured and uncured samples showed G″ peak temperatures of −42 and −45°C at 6.28 rad s−1 latter of which was close to the glass transition temperature of uncured gum of −48°C. The mixing of various fillers showed no effect on the peak temperatures. Time-temperature superposition procedures were applied to the samples through the next way; frequency shifts were determined firstly for tanδ curves, then shifts in magnitude were made for G′ and G″. All shift factors can be expressed by single WLF equation with C1=13.2 and C2=39.7, if we chose G″ peak temperatures as the reference temperatures. It may be concluded that the temperature dependence of the matrix polymer determines that of linear viscoelasticity of rubber materials.