Dilute solutions of poly(vinyl alcohol) derived from vinyl trifluoroacetate

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Abstract
The dilute‐solution behavior of poly(vinyl alcohol) (PVAVTFA), derived from vinyl trifluoroacetate, in water‐dimethylsulfoxide (DMSO) mixtures was investigated. With solvent mixtures ranging from 10 to 20 vol % DMSO, the relation between the reduced viscosity ηsp/C and the polymer concentration C was linear for polymer concentrations above 0.2 g/dL, whereas in solutions in mixed solvents of other compositions the dependence was linear for polymer concentrations above 0.1 g/dL. The relation between the intrinsic viscosity [η] obtained for aqueous solutions of PVAVTFA and the molecular weight M estimated from viscosity measurements in solutions of poly(vinyl acetate) (PVAVTFA), obtained by acetylation of PVAVTFA, was given by [η] = 7.34 × 10−4 M0.63. The value of [η] was greatest for the solvent mixture with 10 vol % DMSO and smallest for about 50 vol % DMSO, and Huggins constants k were smallest and greatest for these two cases, respectively. The turbidity of the solutions of low‐molecular‐weight PVAVTFA, was higher than that of high‐molecular‐weight PVAVTFA up to 30 vol % DMSO, and the reverse relation held for 40‐70 vol % DMSO.