Observation of morphology of polypropylene and high density polyethylene blends under shear flow

Morphology change under shear flow with converging sections of propylene block-copolymers and high density polyethylene blends (PP/PE) was investigated. The results obtained in this study are as follows: 1) The size of the dispersed droplets depended on the shear viscosity ratio (ηr*) of the dispersed phase to the continuous phase, which takes into account the shear rate dependence. 2) In the case of ηr* > 1, dispersed droplets formed clusters because they deformed only very slightly under applied shear flow. Deformation of the dispersed droplets was small and they were stable within our measured shear rate range. 3) The morphology of the PP/PE blends depended on ηr* and the capillary number (Ca*), based on the mean field model. Breakup of the dispersed droplets occurred most when the ηr* value is near 1.