Solubility of Supercritical CO₂ in Polystyrene during Foam Formation via Statistical Associated Fluid Theory (SAFT) Equation of State

Brian A. Ott, G. Caneba

Department of Chemical Engineering, Michigan Technological University.

DOI: 10.4236/jmmce.2010.95029                

Abstract

The use of supercritical fluids, such as CO₂, for polymer foam formation has become popular in the last decade. These physical blowing agents are environmentally responsible, and are able to provide certain processing advantages during foam formation. In order to be able to understand foam formation under relatively high pressures and temperatures, thermodynamic phase equilibrium analysis is required coupled with a good equation of state. The Statistical Associated Fluid Theory (SAFT) equation of state (EOS) is studied in detail for the carbon dioxide/polystyrene system, under supercritical CO₂ conditions. The SAFT EOS is found to perform better than the Soave-Redlich-Kwong (SRK) EOS, especially when considering liquid phase compositions and densities. Experimental data from the literature is used to validate model parameters cited in the literature for polystyrene-CO₂ binary systems under supercritical conditions. The analysis is done with the assumption that the vapor phase is pure CO₂ and in equilibrium with the liquid CO₂-polystyrene condensed phase.

Keywords

Carbon dioxide, polystyrene, SAFT, polymer foams, supercritical fluid

Conflicts of Interest

The authors declare no conflicts of interest.

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