| Abstract: | The investigations reported in this paper aimed at evaluating the impact of a weak interfacial strength on visco-elastic properties in multiphase polymer blends both in the linear and nonlinear deformation regime. Blends of poly(ethylene) and poly(oxymethylene) were used as model systems. The particular choice of the components of the blend was based on the fact that the two components are incompatible, possess strong interfacial energies and thus narrow and weak interfacial layers, and finally that their individual visco-elastic properties are within the same order of magnitude. This allows to evaluate the contributions of the phase boundaries to the visco-elastic properties in a transparent way. We investigated the visco-elastic properties of blends of various compositions by analyzing the stress-strain behavior, the dynamical torsional behavior as well as by determinating their cyclic stress-strain behavior. The experimental finding is that most of the properties studied vary linearly with the composition and are not influenced by the weakness of the interfacial strength–contrary to the expectation. An exception is the elongation at break which varies nonlinearly with the composition and which shows a minimum value at intermediate compositions. The impact of a weak phase coupling on visco-elastic properties is thus rather limited. |
