Stress relaxation in carbon black loaded butyl rubber

The dependence of equilibrium force (F*) on the strain ratio (alpha) of car bon black loaded butyl rubber was studied. The relation between elastic con stant and volume fraction of carbon black was found in good agreement with that obtained by Guth and Gold relation at low concentrations using the sha pe factor (f = 6.5). The relaxation time and viscosity (eta) were calculate d by using stress relaxation of these samples at different compression stra ins. The same agreement was observed in the relation between viscosity and volume fraction of carbon black concentration. The results are discussed ac cording to the dispersion mechanism of carbon black in rubber. (C) 2000 Joh n Wiley & Sons, Inc.