Sorption and Transport Behavior of Carbon Dioxide in Polyimide Films

Sorption and permeability and diffusion time-lag of carbon dioxide in three types of polyimide were measured in the range from 35℃ to 110℃ and upto 3MPa. For polyimides used, the sorption isotherms were concave to the activity axis and the permeability coefficients decreased with an increase in activity. The experimental results were analyzed according to the dual-mode sorption and transport model. The sorption and transport behavior of carbon dioxide in polyimides were satisfactorily described by the fugacity-based expressions of the dual-mode model rather than by the four-mode mobility model proposed by Barrer.