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Effect of Temperature and Pressure on Surface Tension of Polystyrene in Supercritical Carbon Dioxide

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Date

2007-02-15

Authors

Thompson, Russell B.
Park, H.
Lanson, N.
Tzoganakis, C.
Park, Chul B.
Chen, P.

Journal Title

Journal ISSN

Volume Title

Publisher

ACS Publications

Abstract

The surface tension of polymers in a supercritical fluid is one of the most important physicochemical parameters in many engineering processes, such as microcellular foaming where the surface tension between a polymer melt and a fluid is a principal factor in determining cell nucleation and growth. This paper presents experimental results of the surface tension of polystyrene in supercritical carbon dioxide, together with theoretical calculations for a corresponding system. The surface tension is determined by Axisymmetric Drop Shape Analysis-Profile (ADSA-P), where a high pressure and temperature cell is designed and constructed to facilitate the formation of a pendant drop of polystyrene melt. Self-consistent field theory (SCFT) calculations are applied to simulate the surface tension of a corresponding system, and good qualitative agreement with experiment is obtained. The physical mechanisms for three main experimental trends are explained using SCFT, and none of the explanations quantitatively depend on the configurational entropy of the polymer constituents. These calculations therefore rationalize the use of simple liquid models for the quantitative prediction of surface tensions of polymers. As pressure and temperature increase, the surface tension of polystyrene decreases. A linear relationship is found between surface tension and temperature, and between surface tension and pressure; the slope of surface tension change with temperature is dependent on pressure.

Description

This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry B., 111, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/jp065851t

Keywords

self-consistent field theory, surface tension, Axisymmetric drop shape analysis, supercritical carbon dioxide

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Citation