Cross-Linkable Polyimide Membranes for Improved Plasticization Resistance and Permselectivity in Sour Gas Separations

Brian Kraftschik, William J. Koros

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


A series of cross-linkable membrane materials based on the 6FDA-DAM:DABA (3:2) polyimide backbone were synthesized for improved sour gas separation performance, in terms of both membrane stability and permselectivity. Short-chain poly(ethylene glycol) (PEG) molecules were used as cross-linking agents in an esterification-based cross-linking reaction. Pure and mixed gas permeation and pure gas sorption experiments were performed on dense films of these materials. Compared to unmodified 6FDA-DAM:DABA (3:2), higher sour gas permselectivity and membrane stability were achieved under aggressive feed conditions. H2S-induced plasticization was not evident until pure H2S feed pressures greater than approximately 6-8 bar. Pure CO 2-induced plasticization only occurred at feed pressures greater than about 25 bar. Under mixed gas feed conditions with 20% H2S, 20% CO2, and 60% CH4 at 35 C, attractive selectivities above 22 and 27 for H2S/CH4 and CO2/CH4, respectively, were observed for a feed pressure of 62 bar with both triethylene glycol and tetraethylene glycol cross-linking agents. © 2013 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)6908-6921
Number of pages14
Issue number17
StatePublished - Aug 29 2013
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors acknowledge the King Abdullah University of Science and Technology (KAUST) for generously funding this work.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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