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Melt viscosity of polyethylenes
Author(s) -
Aggarwal Sundar L.,
Marker Leon,
Carrano M. J.
Publication year - 1960
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1960.070030711
Subject(s) - branching (polymer chemistry) , activation energy , viscosity , reduced viscosity , intrinsic viscosity , materials science , viscosity index , thermodynamics , relative viscosity , shear rate , atmospheric temperature range , temperature dependence of liquid viscosity , polymer chemistry , melt flow index , analytical chemistry (journal) , composite material , chemistry , polymer , chromatography , organic chemistry , copolymer , scanning electron microscope , base oil , physics
The melt viscosity of fractionated and unfractionated polyethylenes at low shear rates have been measured in the temperature range 140–280°C. The melt index is not an adequate measure of melt viscosity determined at low shear rate. From melt viscosity and intrinsic viscosity determinations on fractions an estimate of the degree of long‐chain branching can be made. From viscosity measurements at several temperatures between 140 and 280°C. values of the apparent activation energy for fractionated and unfractionated polyethylenes were obtained. The activation energy increases from 8 to 13 kcal. as the weight‐average molecular weight increases about 20,000 to about 200,000.