Experimental identification of viscoelastic properties of rubber compounds by means of torsional rheometry

Abstract

Rheological models are used for the description of viscoelastic properties. Such investigations are mostly based on experiments with a torsional rheometer, i.e. a Rubber Process Analyzer. The results of such experiments are storage and loss modulus, which depend on the applied angular frequency. The investigations were performed with rubber compounds used in industry, with different crystallization degrees of the used EPDM basic polymer as well as different filler degrees. Moreover, the influence of melt temperature on these dynamic moduli is considered. For the rheological description of the investigated rubber compounds three different viscoelastic models are used. After derivation of the corresponding relationships for each of the spring-dashpot models the application for rubber compounds was investigated. The best agreement between experiment and model prediction was achieved by a nonlinear viscoelastic model. With such a model the influence of different crystallization and filler degrees on the viscoelastic material properties can be covered.