The effects of humidity on gas transport properties of sulfonated copolyimides
Résumé
Hydrogen, oxygen and carbon dioxide transport properties are studied at various hydration rates for a large series of sulfonated copolyimides synthesized with a naphthalenic dianhydride, a sulfonated diamine and various non-sulfonated diamines. For all copolymers, the gas permeability coeff. decreases when the relative humidity increases in the range 0-70% and an increase of gas flux is obsd. at high hydration. The magnitude of the permeability coeff. variation depends on the gas polarity and on the copolymer compn. A detailed anal. of the gas transport properties at anhyd. state and of the water sorption mechanism as a function of the copolymers compn. allows to explain all the gas permeability variations as a function of hydration