Solvent effect on the miscibility of poly(4-hydroxystyrene)–poly(ethylene oxide) blends

The miscibility of the poly(4-hydroxystyrene) (P4HS) and poly(ethylene oxide) (PEO) blends has been studied using the solvent casting method. Five solvents, acetone, tetrahydrofuran, isopropyl acetate, n-butanol and cyclohexanone, were used. The glass transition and melting temperatures and the crystallization behavior of the blends were studied by differential scanning calorimetry (DSC). The thermal analyses indicate that the blends are miscible using any solvent, where a single glass transition temperature was observed. The crystallization behaviors are discussed in this study. Generally, the crystallization of PEO is more easily suppressed from the tetrahydrofuran and cyclohexanone cast blends. Tetrahydrofuran and cyclohexanone are the best among various solvents, where the blends have more homogeneous morphology. A negative value of the polymer interaction parameter is observed using tetrahydrofuran as the solvent, and this indicates that the polymer blend is miscible in the molten state.