EQUILIBRIUM-CONSTANTS AND PREDICTIONS OF MISCIBILITY WINDOWS AND MAPS FOR POLYMER BLENDS INVOLVING PARA-(HEXAFLUORO-2-HYDROXY-2-PROPYL)STYRENE WITH METHACRYLATE AND ACETOXY GROUPS

Dimensionless equilibrium constants describing the self-association of the hexafluoro-2-phenyl-2-propanol (HFPP) group have been determined from infrared spectroscopic data. Corresponding values of these equilibrium constants for polymers containing the p-(hexafluoro-2-hydroxy-2-propyl)styrene (HFPS) group were calculated by taking into account differences in the molar volume of the model and what we define as the "specific repeat" of the polymer.1 Equilibrium constants describing the interassociation of HFPS with methacrylate and acetoxy type carbonyl groups were obtained from spectroscopic studies of miscible poly[styrene-co-p-(hexafluoro-2-hydroxy-2-propyl)styrene] (STHFPS) blends with poly(n-butyl methacrylate) and an ethylene-co-vinyl acetate copolymer containing 70% vinyl acetate. Relative to vinylphenol, the self-association of HFPS is substantially weaker, while that of interassociation to aliphatic methacrylate and acetoxy type functionalities is roughly comparable. The equilibrium constant values were then used to calculate theoretical miscibility windows and maps for the complete range of blends of STHFPS with poly-(n-alkyl methacrylates) and ethylene-co-vinyl acetate copolymers. In addition, calculations were also performed for poly[styrene-co-p-(hexafluoro-2-hydroxy-2-propyl)-alpha-methylstyrene] with poly(methyl methacrylate) and poly(n-butyl methacrylate). A comparison of the predicted miscibility windows and maps with those of the equivalent vinylphenol copolymer blends reveals that STHFPS blends have a much wider "window of miscibility", and this result is substantiated by experimental results reported in the literature and performed in our laboratories.