CO2 separation properties of a glassy aromatic polyimide composite membranes containing high-content 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid

Abstract

Composite membranes composed of glassy fluorine-containing polyimide (PI) containing up to 81wt% of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][Tf2N]) ionic liquid (IL) were prepared by a casting method. With increased IL content to 51wt%, a microsized domain of IL was formed in the PI matrix. This domain continuously expanded with increased IL content based on the SEM images. The gas permeability of composite membranes was determined at 35°C. With increasing 35wt% IL, the gas permeability of PI+IL membranes linearly decreased, whereas the gas permeability increased from 51 to 81wt% IL content. This increase in gas permeability was attributed to the increase in gas ..