antec article

Abstract

The melt viscosity of three commercial polyolefines (LDPE, LLDPE and HDPE) was measured in uniaxial elongational flow at constant rate. The melts showed the same MFI and similar shear viscosity but differed widely in their extensional properties, reflecting the differences in their molecular structure. Fibre spinning experiments (Rheotens) and the Entry Flow Method were also used to obtain an estimate of the elongational viscosity. It was found that meaningful estimates could be made by these two methods, even in the absence of steady state elongational viscosity, if the amount of accumulated extensional strain in each case was taken into consideration.

SPE antec tech. papers, 45, 1156-1161, 1999

Comparison of three methods to measure the elongational viscosity of polymer melts: Entry flows, fibre spinning and uniaxial elongation