Cross-linking of Polymer of Intrinsic Microporosity (PIM-1) via nitrene reaction and its effect on gas transport property

Abstract Polymer of Intrinsic Microporosity (i.e. PIM-1) has been crosslinked thermally via nitrene reaction using polyethylene glycol biazide (PEG-biazide) as a crosslinker. The crosslinking temperature was optimized using TGA coupled with FT-IR spectroscopy. The dense membranes containing different ratios of PIM-1 to PEG-biazide were cast from chloroform solution. Crosslinking of PIM-1 renders it insoluble even in excellent solvents for the uncrosslinked polymer. The resulting crosslinked membranes were characterized by FT-IR spectroscopy, TGA and gel content analysis. The influence of crosslinker content on the gas transport properties of PIM-1, its density and fractional free volume (FFV) were investigated. Compared to the pure PIM-1 membrane, the crosslinked PIM-1 membranes showed better gas separation performance especially for CO 2 /N 2 , CO 2 /CH 4 and propylene/propane (C 3 H 6 /C 3 H 8 ) gas pairs and as well as suppressed penetrant-induced plasticization under high CO 2 pressure.