Gas permeation, diffusion, sorption and free volume of poly(2-trifluoromethyl-2-pentafluoroethyl-1,3-perfluorodioxole)

Synthesis of a homopolymer based on perfluoro(2-methyl-2-ethyl-dioxole) was performed at 50-60 °C and high pressure (10 kbar). The polymer is amorphous with high glass transition temperature (235 °C), low (among perfluoropolymers) density (1.83 g/cm3) and sufficiently good film-forming properties. The structure of the polymer was tested by 19F- and IR-spectroscopies. Positron annihilation life-time spectroscopy results suggest large size of free volume elements approaching that for perfluorinated copolymer AF2400. The homopolymer is characterized by high gas permeability, diffusion and solubility coefficients and can be considered as good potential material for various membrane gas separations.