Abstract: The dynamic viscoelastic behavior of polysiloxanes filled with ultrafine SiO₂ has become ever-lasting important due to its unique properties. In present article, the influence of SiO₂ treated with silane coupling agent bis(3-triethoxysilyl)tetrasulfane(TESPT) on dynamic viscoelastic properties of uncured polymethylvinylsiloxane(PMVS)/ultra fine-silica(SiO₂) composites was investigated by using an advanced rheometric expansion system(ARES) under the conditions of temperature²5 ℃, strain(γ) from 0.01% to 100% and frequency(ω) from 0.01 to 100 rad/s. The results reveal that the treated SiO₂ particles leads to the frequency-dependent storage modulus(G′) which approaches linear viscoelastic behavior in the lower frequency region. Based on an examination of the dynamic viscoelastic behavior and TEM observation, we owe these characteristics to improved dispersion of SiO₂ particles in the polymer matrix due to their surface-treatment as compared with the untreated case. On the other hand, dynamic viscoelastic behavior sensitively reflects the dispersion of SiO₂ particles with diameters from 100 to 500 nm, which further evidence the promotion of filler dispersion induced by the incorporation of TESPT.

Key words: Silica(SiO₂), Polymethylvinylsiloxane(PMVS), Surface-treatment of particles, Dynamic viscoelasticity