SOLUBILITIES OF CARBON-DIOXIDE AND NITROGEN IN POLYSTYRENE UNDER HIGH-TEMPERATURE AND PRESSURE

The solubilities of nitrogen and carbon dioxide in polystyrene were me asured by a pressure decaying method at temperatures from 373.2 K to 4 53.2 K and pressures up to 20 MPa. The isothermal solubilities of both gases increase almost linearly with pressure. The solubility of carbo n dioxide decreases with increasing temperature. The solubility of nit rogen, however, increases with temperature, and is about 1/16 to 1/7 o f that of carbon dioxide. The solubilities measured are correlated by the Sanchez-Lacombe equation of state using the characteristic paramet ers for nitrogen and carbon dioxide determined in our previous work. T he parameters for polystyrene were determined using the experimental P VT data measured in our laboratory. Agreement between the experimental solubilities and the correlations with a temperature-dependent binary interaction parameter, k(ij), is satisfactory. Henry's constants for carbon dioxide + and nitrogen + polystyrene systems are in relatively good agreement with Durill's data.