Fluorination of polyhydrofluoroethylenes. I. Direct fluorination of poly(vinyl fluoride) film

Abstract

Abstract It has been demonstrated that the poly(vinyl fluoride) film can be fluorinated by exposing the polymer to an environment of fluorine under atmospheric pressure and at ambient temperature. Fluorine content, infrared spectra, thermal properties, and solubilities in the polar solvents were investigated for the fluorinated products and the following results were obtained. In the case of films less than 10 μ in thickness, the fluorination appeared to proceed homogeneously. Under any fluorinating conditions applied, i.e., fluorine pressure of up to 800 mm Hg and temperatures of up to 90°C, the fluorine content never exceeded 65% which corresponds to a composition of C 2 F 2.5 H 1.5 . The activation energy of the reaction was calculated to be 6.8 kcal/mole. The polymer reacted with a small amount of oxygen contained in the fluorine to form acyl fluoride groups. The fluorinated films became insoluble in boiling N , N ‐dimethylformamide, N , N ‐dimethylacetamide, and dimethyl sulfoxide, but colored gradually to a dark brown. The occurrence of some crosslinking in the products was revealed.