Large amplitude oscillatory shear and uniaxial extensional rheology of blends from linear and long-chain branched polyethylene and polypropylene

In this article, normal stresses and shear stresses in oscillatory shear flow are measured at small and large deformation amplitudes. New material parameters are then introduced based on Fourier transform rheology and stress decomposition analysis of normal and shear stress measurements. Furthermore, uniaxial extensional measurements are performed and compared to simulation results using the molecular stress function model. Different behaviors were observed for the polyethylene and polypropylene type blends, which are believed to arise from the different types of long-chain branching (LCB) topology present in each of the systems. The use of the new material parameters proposed and described within this article has the potential to allow for a better understanding of structure-property relationships in industrial LCB materials.