Strain rate and temperature dependence of a nanoparticle-filled poly(dimethylsiloxane) undergoing shear deformation

The mechanical properties in shear of unfilled and nanoparticle-filled polydimethylsiloxane (PDMS) networks are reported. The effect of silicate-based nanoparticles on the mechanical response was studied as functions of rate and temperature using the timetemperature superposition principle. An apparent yielding phenomenon was observed in the filled polymer in spite of the more typical elastomeric behavior exhibited by the pure PDMS network. The timetemperature superposition principle was applied to capture the shear strain rate (10-410-1 s-1) and temperature (-40 to 60 degrees C) dependence of the stress response of the filled PDMS at different strains and at the yield point. A power-law relationship was found to adequately describe the resulting master curves for yield stress in shear. Using a triangular shear displacement profile at 10-2 s-1, the effect of temperature (-20 to 80 degrees C) on the recovery from a particularly pronounced Mullins effect was investigated as a function of rest time. Given adequate rest time (between 10 and 102 min), recovery was observed for the temperature range studied. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012