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Water vapour transport mechanism in naphthalenic sulfonated polyimides
The morphology and the water transport properties of a large series of sulfonated copolyimides synthesised with a naphthalenic dianhydride, a sulfonated diamine and various non-sulfonated diamines were studied. For a sulfonated diamine content in the total diamine amount higher than 30%, the copolym...
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Published in: | Journal of membrane science 2003-09, Vol.223 (1), p.127-139 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The morphology and the water transport properties of a large series of sulfonated copolyimides synthesised with a naphthalenic dianhydride, a sulfonated diamine and various non-sulfonated diamines were studied. For a sulfonated diamine content in the total diamine amount higher than 30%, the copolymers are composed by a continuous ionic phase and a dispersed non-sulfonated phase. The water sorption isotherms are of BET type II for all the copolymers and they result from the contribution of both the sulfonated and non-sulfonated phases. For the sulfonated phase, a two step sorption mechanism has been identified. It consists at low activity in sorption on ionic sites but also in unrelaxed holes formed during the triethylammonium/H
+ ionic exchange and at high activity in a clustering process. The contribution of the non-sulfonated phase to the transport phenomenon can be modulated by the hindrance brought by the non-sulfonated diamine and by its more or less hydrophobic character. |
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ISSN: | 0376-7388 1873-3123 |
DOI: | 10.1016/S0376-7388(03)00315-6 |