POLYMER BLENDS BASED ON POLYOLEFIN ELASTOMER AND POLYPROPYLENE

A new family of homogeneous polyolefin polymers that exhibit unique mo lecular and rheological properties designated polyolefin elastomers (P OEs) are characterized by a narrow molecular weight and high degrees o f comonomer distribution. Because these copolymers are often elastomer ic in nature, one of the uses for these materials is as impact propert ies improver for brittle polymers such as polypropylene at low tempera tures. In this work a study was carried out about the effectiveness of the polyethylene elastomer (POE) as an impact modifier for polypropyl ene in relation to the traditional modifier EPDM. In this study the fl ow properties of of the POE/PP and EPDM/PP blends were also evaluated. The blends were analyzed by solid-state C-13 nuclear magnetic resonan ce (C-13-NMR) spectroscopy, scanning electron microscopy (SEM), and di fferential scanning calorimetry (DSC). The results showed that PEE/PP and EPDM/PP blends present a similar crystalline behavior, which resul ted in a similar mechanical performance of the blends, on the composit ion analyzed. It was also verified that the POE/PP blend presents lowe r torque values than the EPDM/PP blend, which indicates a better proce ssability when POE is used as an impact modifier. (C) 1997 John Wiley & Sons, Inc.