Measurement and modeling of temperature and strain rate dependent uniaxial and planar extensional viscosities for various polypropylene melts in very fast flows

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F70883521%3A28110%2F22%3A63561098" target="_blank" >RIV/70883521:28110/22:63561098 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Measurement and modeling of temperature and strain rate dependent uniaxial and planar extensional viscosities for various polypropylene melts in very fast flows

Original language description

In order to optimize and develop new polymeric materials for advanced polymer processing, it is necessary to know their rheological behavior, especially during uniaxial and planar stretching. However, conventional rheology tools do not allow the flow behavior of polymers to be evaluated under the conditions typical for very fast flows. In this work, novel rectangle and circular orifice (zero-length) dies have been utilized for temperature-strain rate dependent planar and uniaxial extensional viscosity measurements for various polypropylene melts (PP) by using Cogswell and Gibson methodologies and the capability of different constitutive equations to describe the measured experimental data has been tested. Specific attention was paid to recently proposed frame-invariant Generalized Newtonian Fluid constitutive equation [Zatloukal, M., Drabek, J. Generalized Newtonian fluid constitutive equation for polymer liquids considering chain stretch and monomeric friction reduction for very fast flows modeling (2021) Physics of Fluids, 33 (8), art. no. 083106], which uses basic rheological and molecular parameters. For the first time, the monomeric friction coefficient for fully aligned chains was determined for PP using a high-strain-rate limiting value of uniaxial extensional viscosity. As the friction coefficient for the PP melts control flow induced crystallization and extensional rheology at high extensional rates, the results obtained are assumed to be valuable not only with regard to fundamental understanding of polymer physics and development/validation of advanced constitutive equations, but also with respect to understanding stability of non-Newtonian flows in advanced polymer processing, such as, for example, optimized production of polymer membranes for energy storage membranes via cast film process or filtration membranes prepared by the meltblown process used, for example, in production of face masks.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

10404 - Polymer science

Project

<a href="/en/project/GA21-09174S" target="_blank" >GA21-09174S: Viscoelastic non-isothermal modeling of film extrusion process for membranes production including flow induced crystallization</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů