MODELING THE LINEAR VISCOELASTICITY OF UNFILLED AND CARBON-BLACK LOADED ELASTOMERS

Cyclic small strain deformation of unfilled and carbon black loaded vu lcanised elastomers was investigated over a range of strain amplitudes , frequencies, and temperatures in order to determine and model the re sponse of these materials. The elastomer used was a butadiene-acryloni trile base polymer, KRYNAC 806. The carbon black filler was SRF N774 a t a loading of 50 phr (parts per hundred by weight). Experiments were conducted in oscillatory shear using a Weissenberg rheogoniometer. Com plex modulus data were obtained for a range of oscillatory shear strai n amplitudes not exceeding 0.03 rads, for frequencies in the range 5 H z-60 Hz and at temperatures between -20-degrees-C and 20-degrees-C. Ti me-temperature superposition was obtained for data above -10-degrees-C , with the same shifts applicable to both unfilled and carbon black lo aded 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 paramete rs thus, in principle, affords a means of modelling linear deformation s of elastomers containing different loadings of carbon black filler.