Steady-State Shear Flow Properties of Carbon-Black Filled Rubber Compounds
Abstract The steady shear viscosities of four model rubber/carbon-black compounds are measured with a modified Weissenberg Rheometer in a range of moderate shear rates. Yield stresses and low-shear viscosities are determined from creep-flow experiments. Yield stresses are found to increase strongly with filler content while their dependence on temperature can be described by an Arrhenius-type function. Flow curves are reduced to master curves by means of the time-temperature superposition principle. The shift factors are well approximated by the WLF-relation. The contribution of the “secondary” carbon-black network to the viscoelastic behavior requires additional vertical shifting for the filled compounds. Viscosities are found to be in very good agreement with the Herschel-Bulkley model when using the experimentally determined yield values.