Effects of Supercritical CO 2 Conditioning on Cross-Linked Polyimide Membranes

Type
Article

Authors
Kratochvil, Adam M.
Koros, William J.

Date
2010-05-25

Abstract
The effects of supercritical CO2 (scCO2) conditioning on high-performance cross-linked polyimide membranes is examined through gas permeation and sorption experiments. Under supercritical conditions, the cross-linked polymers do not exhibit a structural reorganization of the polymer matrix that was observed in the non-cross-linkable, free acid polymer. Pure gas permeation isotherms and mixed gas permeabilities and selectivities show the cross-linked polymers to be much more stable to scCO2 conditioning than the free acid polymer. In fact, following scCO2 conditioning, the mixed gas CO2 permeabilities of the cross-linked polymers increased while the CO2/CH4 separation factors remained relatively unchanged. This response highlights the stability and high performance of these cross-linked membranes in aggressive environments. In addition, this response reveals the potential for the preconditioning of cross-linked polymer membranes to enhance productivity without sacrificing efficiency in practical applications which, in effect, provides another tool to 'tune' membrane properties for a given separation. Finally, the dual mode model accurately describes the sorption and dilation characteristics of the cross-linked polymers. The changes in the dual mode sorption model parameters before and after the scCO2 exposure also provide insights into the alterations in the different glassy samples due to the cross-linking and scCO2 exposure. © 2010 American Chemical Society.

Citation
Kratochvil AM, Koros WJ (2010) Effects of Supercritical CO 2 Conditioning on Cross-Linked Polyimide Membranes . Macromolecules 43: 4679–4687. Available: http://dx.doi.org/10.1021/ma100535h.

Acknowledgements
The authors acknowledge support by the United States Department of Energy (Grant DE-FG0395ER 14538) and Award KUS-11-011-21 made by King Abdullah University of Science and Technology (KAUST) for this research.

Publisher
American Chemical Society (ACS)

Journal
Macromolecules

DOI
10.1021/ma100535h

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