Solubility of Supercritical CO2 in Polystyrene during Foam Formation via

摘要

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.