On viscous flow in glass-forming organic liquids
File(s)
Published version
Author(s)
Ojovan, Michael I
Type
Journal Article
Abstract
The two-exponential Sheffield equation of viscosity η(T) = A1·T·[1 + A2·exp(Hm/RT)]·[1 + C·exp(Hd/RT)], where A1, A2, Hm, C, and Hm are material-specific constants, is used to analyze the viscous flows of two glass-forming organic materials—salol and α-phenyl-o-cresol. It is demonstrated that the viscosity equation can be simplified to a four-parameter version: η(T) = A·T·exp(Hm/RT)]·[1 + C·exp(Hd/RT)]. The Sheffield model gives a correct description of viscosity, with two exact Arrhenius-type asymptotes below and above the glass transition temperature, whereas near the Tg it gives practically the same results as well-known and widely used viscosity equations. It is revealed that the constants of the Sheffield equation are not universal for all temperature ranges and may need to be updated for very high temperatures, where changes occur in melt properties leading to modifications of A and Hm for both salol and α-phenyl-o-cresol.
Date Issued
2020-09-03
Date Acceptance
2020-09-01
Citation
Molecules, 2020, 25 (17), pp.1-13
ISSN
1420-3049
Publisher
MDPI AG
Start Page
1
End Page
13
Journal / Book Title
Molecules
Volume
25
Issue
17
Copyright Statement
© 2020 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
(CC BY) license (http://creativecommons.org/licenses/by/4.0/).
article distributed under the terms and conditions of the Creative Commons Attribution
(CC BY) license (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
https://www.mdpi.com/1420-3049/25/17/4029
Subjects
Organic Chemistry
0304 Medicinal and Biomolecular Chemistry
0305 Organic Chemistry
0307 Theoretical and Computational Chemistry
Publication Status
Published
Date Publish Online
2020-09-03