The influence of supercritical gases on the phase behavior of polystyrene–cyclohexane and polyethylene–cyclohexane systems: experimental results and modeling with the SAFT-equation of state

Cloud-point curves were measured for polystyrene–cyclohexane–gas and polyethylene–cyclohexane–gas systems to determine the influence of the anti-solvent gases ethane, propane and nitrogen on the conditions for LCST-phase separation of these systems. The experimental results and calculations with the SAFT-equation of state suggest that ethane is the most effective among the considered anti-solvent gases for polymer–cyclohexane systems. It is found that the SAFT-equation can be used to correlate the phase equilibria of the investigated polymer–solvent systems and to predict the phase behavior of polymer–solvent–gas systems qualitatively. However, a quantitatively correct prediction of the influence of the addition of supercritical gases on polymer–solvent phase behavior with SAFT is not possible.