title: Bifunctionalized Intrinsically Microporous Polyimides with Simultaneously Enhanced Gas Permeability and Selectivity.
abstract: Two novel intrinsically microporous copolyimides synthesized by condensation reaction of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 3,3,3',3'-tetramethyl-1,1'-spirobisindane-5,5'-diamino-6,6'-diol, and 3,5-diaminobenzoic acid with diamine ratios of 80/20 (Co-80/20) and 50/50 (Co-50/50) are reported. Unexpectedly, the Co-80/20 not only demonstrates higher microporosity (300 m(2) g(-1) ) than the PIM-6FDA-OH homopolymer (190 m(2) g(-1) ) but also exhibits simultaneously enhanced CO2 permeability (from 119 to 171 Barrer) and CO2 /CH4 selectivity (from 35 to 41) after thermal annealing at 250 °C. This higher permeability originates from enhanced diffusivity (D CO2 ) and the higher selectivity results from its increased diffusion selectivity (D CO2 /D CH4 ). After crosslinking at 300 °C, the Co-80/20 exhibits an even higher CO2 permeability (261 Barrer) and almost unchanged CO2 /CH4 selectivity.
authors.affiliation: Advanced Membranes and Porous Materials Center (AMPMC), Division of Physical Sciences and Engineering, Chemical and Biological Engineering Program, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Kingdom of Saudi Arabia.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Ma
authors.affiliation: Advanced Membranes and Porous Materials Center (AMPMC), Division of Physical Sciences and Engineering, Chemical and Biological Engineering Program, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Kingdom of Saudi Arabia.
authors.forename: Mohsin
authors.initials: M
authors.lastname: Mukaddam
authors.affiliation: Advanced Membranes and Porous Materials Center (AMPMC), Division of Physical Sciences and Engineering, Chemical and Biological Engineering Program, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Kingdom of Saudi Arabia.
authors.forename: Ingo
authors.initials: I
authors.lastname: Pinnau
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D008697:Methane / Q000737:chemistry*; D010539:Permeability; D016062:Porosity; D012117:Resins, Synthetic / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D012117:Resins, Synthetic; D002245:Carbon Dioxide; C029945:polyimide resin; D008697:Methane
keywords: crosslinking; gas separation; hydrogen bonding; intrinsic microporous polymers; polyimides