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 ela stomer (PEE), polypropylene (PP) and PEE/PP blends were analysed using an I nstron capillary rheometer and a Rheometrics dynamic stress rheometer, SR 2 00. 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 e lastomer domains increases as the PEE content increases. The SEM analysis a lso showed that dual-phase continuity may occur between 50 and 60 (wt.%) of PEE. The morphology of the extrudates examined by optical microscopy revea led that a more severe distortion of the extrudate was only observed at hig h PEE content and high shear rate. (C) 2000 Elsevier Science Ltd. Al rights reserved.