Rheological Properties Related to Extrusion of Polyolefins
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School of Mining Engineering and Metallurgy, National Technical University of Athens, Zografou, 15780 Athens, Greece
2
Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, V6T 1Z4 BC, Canada
*
Author to whom correspondence should be addressed.
Academic Editor: Krzysztof Wilczyński
Polymers 2021, 13(4), 489; https://doi.org/10.3390/polym13040489
Received: 10 January 2021
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Revised: 28 January 2021
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Accepted: 30 January 2021
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Published: 4 February 2021
(This article belongs to the Special Issue Advances in Screw Processing of Polymeric Materials - In Memory of Professor James Lindsay White)
Rheological properties related to the extrusion of polyolefins are the shear viscosity, the elongational viscosity, the slip velocity and their temperature- and pressure-dependencies. These properties are measured in the rheology lab mainly via a parallel-plate rheometer and a capillary rheometer. Then appropriate rheological models have to be used to account for all these properties. Such models are either viscous (e.g., the Cross model) or viscoelastic (e.g., the K-BKZ model). The latter gives the best fitting of the experimental data and offers excellent results in numerical simulations, especially in extrusion flows. Wall slip effects are also found and measured by rheometric flows. Modeling of extrusion flows should make use of appropriate slip models that take into effect the various slip parameters, including the effects of shear stress, molecular characteristics, temperature and pressure on the slip velocity. In this paper the importance of these properties in extrusion are discussed.
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Keywords:
shear viscosity; cross model; K-BKZ model; temperature-dependence of viscosity; pressure-dependence of viscosity; slip at the wall
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MDPI and ACS Style
Mitsoulis, E.; Hatzikiriakos, S.G. Rheological Properties Related to Extrusion of Polyolefins. Polymers 2021, 13, 489. https://doi.org/10.3390/polym13040489
AMA Style
Mitsoulis E, Hatzikiriakos SG. Rheological Properties Related to Extrusion of Polyolefins. Polymers. 2021; 13(4):489. https://doi.org/10.3390/polym13040489
Chicago/Turabian StyleMitsoulis, Evan, and Savvas G. Hatzikiriakos. 2021. "Rheological Properties Related to Extrusion of Polyolefins" Polymers 13, no. 4: 489. https://doi.org/10.3390/polym13040489
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