Thermal analysis and its application in evaluation of fluorinated polyimide membranes for gas separation

Abstract
Seven polyimides based on (4,4′-hexafluoroisopropylidene) diphthalic anhydride, 6FDA, with different chemical structures were synthesized in a single pot two-step procedure by first producing a high molecular weight polyamic acid (PAA), followed by reaction with acetic anhydride to produce polyimide (PI). The resulting polymers were characterized using thermal analysis techniques including TGA, derivative weight analysis, TGA-MS, and DSC. The decarboxylation-induced thermal cross-linking, ester cross-linking through a diol, and ion-exchange reactions of selected polyimide membranes were investigated. Cross-linking of polymer membranes was confirmed by solubility tests and CO 2 permeability measurements. The thermal analysis provides simple and timesaving opportunities to characterize the polymer properties, the ability to optimize polymer cross-linking conditions, and to monitor polymer functionalization to develop high performance polymeric membranes for gas separations. © 2011 Elsevier Ltd. All rights reserved.

Citation
Qiu W, Chen C-C, Kincer MR, Koros WJ (2011) Thermal analysis and its application in evaluation of fluorinated polyimide membranes for gas separation. Polymer 52: 4073–4082. Available: http://dx.doi.org/10.1016/j.polymer.2011.07.002.

Acknowledgements
This research was supported by KAUST (King Abdullah University of Science and Technology) and U.S. Department of Energy Grant DE-FG02-04ER15510. We appreciate Hua-Wei Chu in Dr. Cliff Henderson's group at Georgia Tech who helped on TGA-MS measurement.

Publisher
Elsevier BV

Journal
Polymer

DOI
10.1016/j.polymer.2011.07.002

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