Authors:	Wolf, Bernhard A.
Title:	Shear thinning : determination of zero-shear viscosities from measurements in the non-Newtonian region
Online publication date:	3-Aug-2021
Year of first publication:	2020
Language:	english
Abstract:	Experimental information on the viscosities, η, of polymer solutions and of polymer melts as a function of shear rate is modeled by means of an approach that describes the diminution of ln η as a function of shear stress, τ, in terms of an exponential decay. The approach uses the following three adjustable parameters: the zero-shear viscosity of the system, a characteristic shear stress, quantifying its susceptibility toward shear thinning, and a dimensionless parameter stating the magnitude of the effect. This procedure gives access to the Newtonian behavior also in cases where direct measurements are impractical or impossible; it discloses two phenomena not reported so far: a qualitative change in the efficacy of τ at a characteristic concentration and indicates the occurrence of two different disentanglement mechanisms in thermodynamically unfavorable solvents.
DDC:	540 Chemie 540 Chemistry and allied sciences
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 09 Chemie, Pharmazie u. Geowissensch.
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-6232
Version:	Published version
Publication type:	Zeitschriftenaufsatz
License:	CC BY-NC
Information on rights of use:	https://creativecommons.org/licenses/by-nc/4.0/
Journal:	Macromolecular chemistry and physics 221 14
Pages or article number:	2000130
Publisher:	Wiley-VCH
Publisher place:	Weinheim
Issue date:	2020
ISSN:	1521-3935
Publisher URL:	https://doi.org/10.1002/macp.202000130
Publisher DOI:	10.1002/macp.202000130
Appears in collections:	JGU-Publikationen