PERMEABILITY OF FLUORINE AND SOME OTHER FLUORINE-CONTAINING GASES THROUGH NONPOROUS FLUORINE-STABLE COPOLYMERS

The permeability of fluorine, hydrogen fluoride, and uranium and tungsten hexafluoride through nonporous vinylidene fluoride-perfluorodioxolane (copolymer I) and the ternary copolymer tetrafluoroethylene-hexafluoropropylene- perfluoropropyl ether was studied. The membranes used were 100 ± 2 μm thick. The thickness and area of the membranes were measured to within 1%. The pressure of the experimental gases ranged from 0.01 to 0.1 MPa and stabilized to within 0.1%. The cell temperature was maintained constant at 25°C to within 0.05%.Thus, the computed error in determining the permeability of gases in the experiments did not exceed 5%. It was observed that the permeability of hydrogen fluoride through copolymer I was 3-5 times lower than through other fluoroplastics based on vinylidene fluoride. The results also showed that the permeability of fluorine through copolymers I and II was several-fold higher than that of other experimental fluoropolymers.