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Correlations between the Shape of Viscosity Functions and the Molecular Structure of Long-Chain Branched Polyethylenes

✍ Scribed by Florian J. Stadler; Helmut Münstedt

Publisher
John Wiley and Sons
Year
2009
Tongue
English
Weight
627 KB
Volume
294
Category
Article
ISSN
1438-7492

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✦ Synopsis

Abstract

The viscosity functions of long‐chain branched metallocene‐catalyzed ethene homopolymers and copolymers (LCB‐mPE) were described by an extended Carreau‐Yasuda model. The two characteristic relaxation times, λ~1~ and λ~2~, and the slope of the viscosity function between these two characteristic relaxation times can be correlated to the zero shear‐rate viscosity, η~0~, and the molar mass $\overline M _{\rm w} $. The characteristic relaxation times, λ~1~ and λ~2~ (describing the main curvatures of the viscosity function) exhibit a power law dependency on the molar mass, $\overline M _{\rm w} $. The parameterization of the viscosity function can be used for a molecular characterization and flow simulations of various kinds.

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