Modeling Phase Equilibria of Polystyrene in Methylcyclohexane Solutions with SWP Equation of State

In this paper stability and phase equilibria of polystyrene in methylcyclohexane solution using SWP equation of state, which has been modeled by Browarzik et al., is redone. The mentioned solution is used in microencapsulation process. Since polymer solutions are complex, continuous thermodynamics method is used to study their phase equilibria. Schulz-Flory distribution function is used to show polydispersity of polymer. In a certain temperature region, Pressureconcentration diagram of monodisperse system of polystyrene in methylcyclohexane shows upper critical point and lower critical point. Lowering the temperature causes these curves to approach and turn into hour glass shaped curves. In this paper this behavior and the effect of polydispersity on stability and phase equilibria are studied.