The Rheology of Rubber Compounds with Rubber Flour

Abstract

During the course of investigations into the rheological characteristics of SBR rubber compounds containing rubber flour as a function of the rubber flour content, we observed some distinctive features. Based on the results for the activation energy of viscous flow of the compounds under investigation and the specific characteristics of the rubber flour particles, we put forward a hypothesis for the flow mechanism. The assumption can be made that the rubber flour particles are deformed in the viscous medium of the SBR matrix during flow. The degree of deformation is largely dependent on the presence of other ingredients in the compound (carbon black, stearic acid, carbon black + stearic acid). We suggest that the amount of unvulcanised rubber in the rubber flour particles is very important to the flow mechanism. It is also likely that rubber flour particles are broken up during flow. The proposed hypothesis for the flow mechanism is compared with the known models of “drop breakup in extensional flow”, “core-shell”, polymer blends comprising two incompatible polymers or comprising a thermoplastic and microgel particles, etc.