Evaluation of Phase Morphology and its Impact on the Viscoelastic Response of Elastomer Blends

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The project focuses on a deeper understanding of correlations between phase separation processes, the resulting phase morphology and related viscoelastic properties after crosslinking of unfilled and filled elastomer blends. One main objective is the microstructure based modelling and numerical simulation of spinodal decomposition with realistic physical input parameters obtained from separate phase-specific measurements. In this frame also the influence of mechanical stress fields on the phase morphology will be analysed. A further goal is the development of physically motivated models and simulation tools for the high-frequency viscoelastic response of elastomer blends based on the detailed phase morphology, e.g. domain and interphase size, filler distribution and crosslinking heterogeneities. The project is founded on two columns of numerical and theoretical (OvGU, DIK) as well as experimental (DIK) investigations, respectively. Herein, the main attention lies on the establishment of new concepts for describing the complex phase-behaviour of filler reinforced elastomer blends. Due to its physical motivation and the sound implementation into numerical tools, phase field modelling will be the method of choice. The experimental focus lies on the evaluation of thermodynamic polymer-polymer- and polymer-filler interaction parameters that govern the phase morphology and filler distribution. In addition, the collective chain mobility is estimated from viscoelastic and dielectric spectra of the poor polymer melts, which are adapted by a well-established molecular-rheological model of chain reptation in entangled polymer melts.