Phase behavior of the ternary system solvent: poly(γ-benzyl L-glutemate) and polystyrene

Summary Phase equilibria were investigated at 80°C for a ternary system involving a solvent benzyl alcohol, a rodlike polymer poly(-benzyl L-glutamate) (PBLG), and a flexible polymer polystyrene (PS). The fairly dilute solution of the two polymers was isotropic and monophasic. At greater concentrations, it was separated into two isotropic phases. Above an even higher critical concentration of the two polymers, three phases, a cholesteric (A₁) and two isotropic phases (I₁ and I₂), coexisted at equilibrium. PBLG was contained exclusively in the phases A₁ and I₁, while PS was in the phase I₂. The more concentrated solution was separated into a cholesteric phase and an isotropic phase. The latter contained PS but excluded PBLG, These features were discussed on the ground of the Flory theory by considering the polymer compatibility.