EFFECT OF CURE SYSTEMS ON SHRINKABILITY OF POLYOLEFIN-EPDM BLENDS

Effects of cure systems on shrinkability of polyolefin and EPDM blends have been studied as a function of cure time and amount of elastomers added. During measurement one of the parameters is kept constant whil e the other varies. The shrinkability of the blends increases with the increase in cure time when elastomer content is fixed. Similarly, at constant cure time higher loading of elastomer increases the shrinkabi lity of the blends. Samples stretched under high temperature show high er shrinkability than those stretched under room temperature. Dicumylp eroxide (DCP) is a more effective curing agent for making a particular set of blends more shrinkable than the sulfur. The changing morpholog ical pattern with DCP-cured shrunk samples from those of sulfur cured samples is corroborated by the SEM studies where the elastomer phase a ppears to be globular in nature. The crystallinity of the blend depend s on the dose and type of the elastomer used in polyolefin. The curing efficiency of the elastomerphase depends on the polyolefin used as bl end partner. (C) 1998 John Wiley & Sons, Inc.