A series of higher permeability polyamide-imides based on 2,2′-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride with comparable plasticization resistance to Torlon were synthesized and formed into dense film membranes. Polymers possessing 2,4-diamino mesitylene (DAM) were stable up to 56 atm of pure CO 2, which is due to enhanced charge transfer complex formation compared to polymers containing 4,4′- (hexafluoroisopropylidene) dianiline (6FpDA) and 2,3,5,6-tetramethyl-1,4- phenylenediamine (TmPDA). The new polymers containing DAM and TmPDA showed ideal CO 2/CH 4 selectivities of near 50 with CO 2 and H 2S permeabilities over an order of magnitude higher than Torlon. CO 2 and CH 4 sorption in the DAM- and TmPDA-based materials was reduced, whereas H 2S sorption was enhanced relative to membranes containing fluorinated 6FpDA. Consequently, DAM- and TmPDA-based membranes showed increased stability toward high pressure CO 2 but lower plasticization resistance toward pure H 2S. These results highlight the differences between CO 2 and H 2S that challenge the rational design of materials targeting simultaneous separation of both contaminants. © 2012 American Chemical Society.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-I1-011-21
Acknowledgements: This publication is based on work supported by Award No. KUS-I1-011-21, made by King Abdullah University of Science and Technology (KAUST). The authors would also like to thank Dr. JR Johnson and Dr. Oguz Karvan (Ga. Tech.) for design and construction of the H2S systems as well as Megan Lydon (Ga. Tech.) for assistance in the XRD measurements.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.