THE EFFECT OF BLOWN FILM PROCESSING ON CONVENTIONAL AND METALLOCENE CATALYSED POLYETHYLENES

摘要

Films were prepared from a range of conventional and metallocene polyethylene (mPE) resins of various comonomer types (butene, hexene, octene), using a Killion blown film extrusion system. The films were manufactured using blow up ratios (BUR) 1.3 ― 2.5, haul-off rates, and screw speeds to give a uniform thickness of 50 microns. Tensile analysis of the samples showed that modulus and elongation were related to both comonomer type and polymer density. The mPE resins showed considerable improvement in mechanical performance compared to conventional PEs. Differential Scanning Calorimetry analysis showed that the degree of crystallinity was more dependent on extrusion processing conditions and polymer density than comonomer type.