Modeling the viscoelastic behavior of elastomer blends including a diffuse interphase

Abstract

Blending elastomers is an attractive method for achieving desired mechanical properties in materials. While the experimental characterization of the viscoelastic properties is usually feasible for the pure phases, it can be difficult or even impossible for blends due to their components’ interactions and the complex behavior resulting from their different glass transition temperatures. Typically, blending elastomers results in heterogeneous morphologies comprising regions with (almost) pure phases and finite interphases. The pure phases and interphases both significantly influence the viscoelastic properties. Material modeling and numerical simulations can be employed to understand the phase interactions better and predict the resulting viscoelastic properties. In this contribution, we model and simulate a representative element of a binary blend consisting of natural rubber and styrene butadiene rubber. We use microscope images as the basis for the morphology that we input in our finite element simulations. The morphology is stored within a phase parameter for each spatial point in the domain and is evolved in an Allen–Cahn framework to create differently sized diffuse interphases. These are subsequently used for mechanical simulations to investigate the influence on the storage and loss moduli. Different blend ratios are approached.