Interactions and prediction of phase diagrams in ternary blends comprising poly(vinyl acetate), poly(vinyl p-phenol), and poly(methyl methacrylate)

This study investigated and discovered a new miscible ternary blend system comprising three amorphous polymers: poly(vinyl acetate) (PVAc), poly(vinyl p-phenol) (PVPh), and polydnethyl methacrylate) (PMMA) using thermal analysis and optical and scanning electron microscopies. The ternary compositions are largely miscible except for a small region of borderline ternary miscibility near the side, where the binary blends of PVAc/PMMA are originally of a borderline miscibility with broad T_g. In addition to the discovering miscibility in a new ternary blend, another objective of this study was to investigate whether the introduction of a third polymer component (PVPh) with hydrogen bonding capacity might disrupt or enhance the meta-stable miscibility between PVAc and PMMA. The PVPh component does not seem to exert any "bridging effect" to bring the mixture of PVAc and PMMA to a better state of miscibility; neither does the Δ_χ effect seem to disrupt the borderline miscible PVAc/PMMA blend into a phase-separated system by introducing PVPh. Apparently, the ternary is able to remain in as a miscible state as the binary systems owing to the fact that PVPh is capable of maintaining roughly equal H-bonding interactions with either PVAc or PMMA in the ternary mixtures to maintain balanced interactions among the ternary mixtures.