Cross-linked polyimide membranes selectivity

The gas permeation parameters have also been reported for polymers obtained via ether reaction of epoxy and diamines [57,58], for polymer blends with acetylene-terminated oligomer [73,74] and internal acetylene polyimide [72,75]. The gas permeability of cross-linked internal acetylene-containing polymer, 6FDA-TeMPD/p-intA (4 1) declines from 612 to 186Barrer, while the selectivity, a(C02/CH4) increases from 14 to 25 at 35°C and lOatm [75]. Moreover, this cross-linked 6FDA-TeMPD/p-intA (4 1) membrane is still stable under CO2 pressure of about 47 atm. 

Ultimately, the researchers found the separation factors of the cross-hnked membranes to be in the order thermally treated diamine cross-linked membrane > thermally cross-linked membrane > diol cross-linked membrane the fluxes were in the opposite order. Thus, they concluded that compared with other polymeric membranes, the membranes in that study exhibited impressive fluxes and comparable separation factors, which contribute to the selection of suitable monomers for polyimide synthesis and effective cross-linking modifications of the resultant polyimide. 

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