Phase behavior of a ternary system of poly[p-perfluorooctyl-ethylene(oxy, thio, sulfonyl)methyl styrene] and poly[p-decyl(oxy, thio, sulfonyl)methyl styrene] in supercritical solvents

In this study, the high-pressure phase behavior of poly[p-decyl(oxy, thio, sulfonyl)methyl styrene] and poly[p-perfluorooctyl-ethylene(oxy, thio, sulfonyl)methyl styrene] in supercritical solvents comprised of carbon dioxide (CO2) and dimethyl ether (DME) were examined. When the poly[p-perfluorooctyl-ethylene(oxy, thio, sulfonyl)methyl styrene] + CO2 systems were evaluated, cloud-point pressures were obtained at temperatures ranging from 60 to 180 °C and pressures of up to 1300 bar. In addition, the poly[p-perfluorooctyl-ethylene(oxy, thio, sulfonyl)methyl styrene] + DME mixtures dissolved at temperatures under 180 °C and pressures under 200 bar, but the poly[p-decyl(oxy, thio, sulfonyl)methyl styrene] + CO2 mixtures did not dissolve, even at 230 °C and 2800 bar. However, the poly[p-decyl(oxy, thio, sulfonyl)methyl styrene] + DME mixtures readily dissolved at temperatures and pressures under 180 °C and 200 bar, respectively. Furthermore, the cloud-point curves for the poly(p-decyl sulfonyl methyl styrene) + DME mixtures with 15.6, 44.3 and 56.4 wt% CO2 changed the P–T curve from a lower critical solution temperature (LCST) type to an upper critical solution temperature (UCST) type at increased CO2 concentrations.