ISSN:
1022-1352
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The effect of molecular weight on sharkskin dynamics is systematically studied using three metallocene-catalyzed linear low density polyethylenes (mLLDPE) of different molecular weights. A new experimental method is developed to enable in-situ characterization of the time scale τ on which sharkskin forms on the extrudate. This laser scattering technique directly measures the periodic variation of the refracted light of the rough sharkskin-like extrudate surface. It is found that τ increases with molecular weight as strongly as the overall molecular chain relaxation time, τ*, determined from oscillatory shear measurements. The observed molecular weight dependence provides additional support for the recently proposed interfacial stress growth/relaxation mechanism for sharkskin formation.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
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