Solubility of Supercritical CO_{2} in Polystyrene during Foam Formation via Statistical Associated Fluid Theory (SAFT) Equation of State

Abstract

The use of supercritical fluids, such as CO_{2}, 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 CO_{2} 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-CO_{2} binary systems under supercritical conditions. The analysis is done with the assumption that the vapor phase is pure
CO_{2} and in equilibrium with the liquid CO_{2}-polystyrene condensed phase.

The use of supercritical fluids, such as CO

Cite this paper

B. Ott and G. Caneba, "Solubility of Supercritical CO_{2} in Polystyrene during Foam Formation via Statistical Associated Fluid Theory (SAFT) Equation of State," *Journal of Minerals and Materials Characterization and Engineering*, Vol. 9 No. 5, 2010, pp. 411-426. doi: 10.4236/jmmce.2010.95029.

B. Ott and G. Caneba, "Solubility of Supercritical CO

References

[1] Sato, Y., et al., Solubilities of carbon dioxide and nitrogen in polystyrene under high
temperature and pressure. Fluid Phase Equilibria, 125, (1996), 129.

[2]
Prausnitz, J.M., R.N. Lichtenthaler, and E.G. de Azevedo, Molecular Thermodynamics of Fluid-Phase Equilibria. 3^{rd} ed. 1999, Prentice Hall, Upper Saddle River, NJ.

[3]
Dolezalek, F., Zur Theorie der binaren Gemische und konzentrierten Losungen. Z. Phys. Chem., 64, (1908), 727.

[4]
Carnahan, N.F. and K.E. Starling, Equation of State for Nonattracting Rigid Spheres. The Journal of Chemical Physics,. 51(2), (1969), 635.

[5]
Beret, S. and J.M. Prausnitz, Perturbed Hard-Chain Theory: An Equation of State for
Fluids Containing Small or Large Molecules. AIChE Journal, 21(6), (1975) 1123.

[6]
Wertheim, M.S., Fluids with Highly Directional Attractive Forces. I. Statistical
Thermodynamics. Journal of Statistical Physics,. 35(1), (1984) 19.

[7]
Wertheim, M.S., Fluids with Highly Directional Attractive Forces. II. Thermodynamic Perturbation Theory and Integral Equations. Journal of Statistical Physics, 35(1), (1984),35.

[8]
Wertheim, M.S., Fluids with Highly Directional Attractive Forces. III. Multiple
Attraction Sites. Journal of Statistical Physics,. 42(3), (1986) 459.

[9]
Wertheim, M.S., Fluids with Highly Directional Attractive Forces. IV. Equilibrium
Polymerization. Journal of Statistical Physics, 42(3), (1986), 477.

[10]
Chapman, W.G., et al., SAFT: Equation-of-State Solution Model for Associating Fluids. Fluid Phase Equilibria,. 52, (1989), 31.

[11]
Huang, S.H. and M. Radosz, Equation of State for Small, Large, Polydisperse, and
Associating Molecules. Ind. Eng. Chem. Res.,. 29, (1990), 2284.

[12]
Huang, S.H. and M. Radosz, Equation of State for Small, Large, Polydisperse, and
Associating Molecules: Extension to Fluid Mixtures. Ind. Eng. Chem. Res.,. 30(8),
(1991), 1994.

[13]
Chen, S.S. and A. Kreglewski, Applications of the Augmented van der Waals Theory of Fluids. I. Pure Fluids. Berichte der Bunsen-Gesellschalt,. 81(10), (1977), 1048.

[14]
Topliss, R., Techniques to Facilitate the Use of Equations of State for Complex Fluid-
Phase Equilibria. 1985, University of California, Berkeley.

[15]
Huang, S.H. and M. Radosz, Additions and Corrections. Industrial and Engineering
Chemistry, 32, (1993), 178.

[16]
Rowlinson, J., Swinton, F, Liquids and Liquid Mixtures. 3rd ed. 1982, London:
Butterworth Scientific.

[17]
Ott, B., “Fluid Phase Equilibrium as modeled by the Statistical Associated Fluid Theory (SAFT) Equation of State”, Ph.D. Dissertation, Michigan Technological University, 2009.

[18]
Vargaftik, N.B., Tables on the Thermophysical Properties of Liquids and Gases. 1975, Washington, D.C.: Hemisphere Publishing Co.

[19]
Suzuki, K., et al., Isothermal Vapor-Liquid Equilibrium Data for Binary Systems at High Pressures. Journal of Chemical and Engineering Data, 35, (1990), 63.

[20]
Behme, S., G. Sadowski, and W. Arlt, Modeling of the separation of polydisperse
polymer systems by compressed gasses. Fluid Phase Equilibria, 158-160, (1999), 869.