Rheological and morphological properties of blends based on ethylene-octene copolymer and polypropylene

Rheological studies have been performed on polymer blends based on ethylene-octene copolymer and polypropylene. The flow behaviour of polyethylene elastomer (PEE), polypropylene (PP) and PEE/PP blends were analysed using an Instron capillary rheometer and a Rheometrics dynamic stress rheometer, SR 200. A non-Newtonian flow behaviour was observed in all the samples at high shear rates, and a Newtonian flow behaviour at shear rates in the range of low values. The scanning electron micrographs showed that the size of the elastomer domains increases as the PEE content increases. The SEM analysis also showed that dual-phase continuity may occur between 50 and 60 (wt.%) of PEE. The morphology of the extrudates examined by optical microscopy revealed that a more severe distortion of the extrudate was only observed at high PEE content and high shear rate. (C) 2000 Elsevier Science Ltd. Al rights reserved.