A NOVEL CALIBRATION FOR THE CHARACTERIZATION OF POLYETHYLENE COPOLYMERS BY TEMPERATURE RISING ELUTION FRACTIONATION

A fresh appraisal of the analytical temperature rising elution fractio nation (TREF) technique is presented. It is shown that by using linear paraffins and low molecular weight polyethylenes as standards, a new, generalized calibration procedure for TREF can be defined. This allow s polyethylene copolymers to be characterized in terms of the length o f the methylene sequences between branches. Such a calibration relates directly to the crystallization behaviour of the copolymer, and is ve ry useful for a proper understanding of chain structure in linear low density polyethylene materials.