IPP HDPE BLENDS - INTERACTIONS AT LOWER HDPE CONTENTS/

Mechanical and rheological properties of blends of polypropylene (PP) and linear polyethylene (PE) were studied, with particular attention t o the effects of aging of such mixtures. These two olefin polymers are basically incompatible. In PP-rich blends, addition of high-density P E (HDPE) causes only a slight decrease in tensile properties and impac t resistance of injection-molded specimens. In all cases, annealed spe cimens have higher moduli and lower impact strength than as-molded pro ducts. While none of these changes are very drastic, the addition of s mall amounts of HDPE was observed to result in a serious decrease of g ate-region impact resistance of thin-walled moldings. Blends with 10-2 0% HDPE exhibited an unexpected interaction in tensile, thermal, and m elt-flow properties as well as in crystallization behavior. (C) 1995 J ohn Wiley & Sons, Inc.