Modelling the linear viscoelasticity of unfilled and carbon black loaded elastomers

Abstract

Cyclic small strain deformation of unfilled and carbon black loaded vulcanised elastomers was investigated over a range of strain amplitudes, frequencies, and temperatures in order to determine and model the response of these materials. The elastomer used was a butadiene-acrylonitrile base polymer, KRYNAC 806. The carbon black filler was SRF N774 at a loading of 50 phr (parts per hundred by weight). Experiments were conducted in oscillatory shear using a Weissenberg rheogoniometer. Complex modulus data were obtained for a range of oscillatory shear strain amplitudes not exceeding 0.03 rads, for frequencies in the range 5 Hz–60 Hz and at temperatures between −20°C and 20°C. Time-temperature superposition was obtained for data above −10°C, with the same shifts applicable to both unfilled and carbon black loaded materials. Shifts were represented using the WLF equation. It was found that reduced data over a range of ten decades of log frequency were well represented by a Huet model. Varying the Huet model parameters thus, in principle, affords a means of modelling linear deformations of elastomers containing different loadings of carbon black filler.