Influence of Active Fillers in Elastomers on the Anisotropic Mullins Effect

Abstract

The first uniaxial extension of an elastomer causes stress softening (the Mullins effect) not only in this loading direction but in any other direction of subsequent extension. However, the Mullins effect is less pronounced after a change of loading direction than in the direction of the initial loading. As a function of the material's deformation history, its mechanical behaviour is distinctly anisotropic. In the interests of providing a more comprehensive evaluation of the anisotropic Mullins effect, the role of the active fillers carbon black and silica was investigated. In particular, the influence of carbon black properties, such as specific surface area and structure, and of the amount of carbon black incorporated, was determined experimentally. Comparing carbon black- and silica-filled elastomers as well as different rubbers provided more insights into the anisotropic material behaviour of filled elastomers.