Understanding Activation Volume in Glass-Forming Polymer Melts via Generalized Entropy Theory

2020 ◽  
Vol 53 (17) ◽  
pp. 7239-7252 ◽  
Author(s):  
Wen-Sheng Xu ◽  
Jack F. Douglas ◽  
Wenjie Xia ◽  
Xiaolei Xu
Keyword(s):  
Activation Volume ◽  
Polymer Melts ◽  
Entropy Theory ◽  
Generalized Entropy ◽  
Glass Forming

scholarly journals Generalized entropy theory of glass-formation in fully flexible polymer melts

2016 ◽  
Vol 145 (23) ◽  
pp. 234509 ◽  
Author(s):  
Wen-Sheng Xu ◽  
Jack F. Douglas ◽  
Karl F. Freed
Keyword(s):  
Glass Formation ◽  
Polymer Melts ◽  
Entropy Theory ◽  
Generalized Entropy ◽  
Flexible Polymer

Advances in the generalized entropy theory of glass-formation in polymer melts

2014 ◽  
Vol 141 (23) ◽  
pp. 234903 ◽  
Author(s):  
Jacek Dudowicz ◽  
Jack F. Douglas ◽  
Karl F. Freed
Keyword(s):  
Glass Formation ◽  
Polymer Melts ◽  
Entropy Theory ◽  
Generalized Entropy

scholarly journals Activation volume in superpressed glass-formers

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Aleksandra Drozd-Rzoska
Keyword(s):  
Molecular Weight ◽  
Relaxation Time ◽  
Absolute Stability ◽  
Activation Volume ◽  
Stability Limit ◽  
Low Molecular Weight ◽  
Glass Forming ◽  
Deep Earth ◽  
Structural Relaxation Time ◽  
The Given

Abstract In pressurized glass-forming systems, the apparent (changeable) activation volume Va(P) is the key property governing the previtreous behavior of the structural relaxation time (τ) or viscosity (η), following the Super-Barus behavior: $${\boldsymbol{\tau }}{\boldsymbol{(}}{\boldsymbol{P}}{\boldsymbol{)}}{\boldsymbol{,}}{\boldsymbol{\eta }}{\boldsymbol{(}}{\boldsymbol{P}}{\boldsymbol{)}}{\boldsymbol{\propto }}{\bf{\exp }}{\boldsymbol{(}}{{\boldsymbol{V}}}_{{\boldsymbol{a}}}{\boldsymbol{(}}{\boldsymbol{P}}{\boldsymbol{)}}{\boldsymbol{/}}{\boldsymbol{R}}{\boldsymbol{T}}{\boldsymbol{)}}$$ τ ( P ) , η ( P ) ∝ exp ( V a ( P ) / R T ) , T = const. It is usually assumed that Va(P) = V#(P), where $${{\boldsymbol{V}}}^{{\boldsymbol{\#}}}{\boldsymbol{(}}{\boldsymbol{P}}{\boldsymbol{)}}={\boldsymbol{R}}{\boldsymbol{T}}{\boldsymbol{d}}\,{\boldsymbol{ln}}\,{\boldsymbol{\tau }}{\boldsymbol{(}}{\boldsymbol{P}}{\boldsymbol{)}}{\boldsymbol{/}}{\boldsymbol{d}}{\boldsymbol{P}}$$ V # ( P ) = R T d ln τ ( P ) / d P or $${{\boldsymbol{V}}}^{{\boldsymbol{\#}}}{\boldsymbol{(}}{\boldsymbol{P}}{\boldsymbol{)}}{\boldsymbol{=}}{\boldsymbol{R}}{\boldsymbol{T}}{\boldsymbol{d}}\,{\boldsymbol{ln}}\,{\boldsymbol{\eta }}{\boldsymbol{(}}{\boldsymbol{P}}{\boldsymbol{)}}{\boldsymbol{/}}{\boldsymbol{d}}{\boldsymbol{P}}$$ V # ( P ) = R T d ln η ( P ) / d P . This report shows that Va(P) ≪ V#(P) for P → Pg, where Pg denotes the glass pressure, and the magnitude V#(P) is coupled to the pressure steepness index (the apparent fragility). V#(P) and Va(P) coincides only for the basic Barus dynamics, where Va(P) = Va = const in the given pressure domain, or for P → 0. The simple and non-biased way of determining Va(P) and the relation for its parameterization are proposed. The derived relation resembles Murnaghan - O’Connel equation, applied in deep Earth studies. It also offers a possibility of estimating the pressure and volume at the absolute stability limit. The application of the methodology is shown for diisobutyl phthalate (DIIP, low-molecular-weight liquid), isooctyloxycyanobiphenyl (8*OCB, liquid crystal) and bisphenol A/epichlorohydrin (EPON 828, epoxy resin), respectively.

The importance of the activation volume for the description of the molecular dynamics of glass-forming liquids

2012 ◽  
Vol 24 (6) ◽  
pp. 065105 ◽  
Author(s):  
K Kaminski ◽  
S Pawlus ◽  
K Adrjanowicz ◽  
Z Wojnarowska ◽  
P Wlodarczyk ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Activation Volume ◽  
Glass Forming

What is the flow activation volume of entangled polymer melts?

2011 ◽  
Vol 290 (1) ◽  
pp. 23-29
Author(s):  
José A. Martins ◽  
Vera S. Cruz ◽  
Joanna Krakowiak ◽  
Weidong Zhang
Keyword(s):  
Activation Volume ◽  
Polymer Melts ◽  
Flow Activation ◽  
Entangled Polymer ◽  
Entangled Polymer Melts
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