Advanced

Polysulfones with highly localized imidazolium groups for anion exchange membranes

Weiber, Annika LU and Jannasch, Patric LU (2015) In Journal of Membrane Science 481. p.164-171
Abstract
In order to promote phase separation and properties of anion-exchange membranes (AEMs)we have prepared polysulfones with an exceptionally high local concentration of imidazolium groups. Statistical copolymers containing single dioxyphenylene rings directly functionalized with four cationic groups were synthesized by polycondensations of 4,4’-dichlorodiphenylsulfone, 4,4′-isopropylidenediphenol and tetramethylhydroquinone, followed by complete benzylic bromination and quaternization using N-methylimidazole, as well as trimethyl amine for reference. In contrast to the quaternary ammonium (QA) containing materials, the thermal stability of the imidazolium (Im) functionalized AEMs increased with the cationic content and only decomposed above... (More)
In order to promote phase separation and properties of anion-exchange membranes (AEMs)we have prepared polysulfones with an exceptionally high local concentration of imidazolium groups. Statistical copolymers containing single dioxyphenylene rings directly functionalized with four cationic groups were synthesized by polycondensations of 4,4’-dichlorodiphenylsulfone, 4,4′-isopropylidenediphenol and tetramethylhydroquinone, followed by complete benzylic bromination and quaternization using N-methylimidazole, as well as trimethyl amine for reference. In contrast to the quaternary ammonium (QA) containing materials, the thermal stability of the imidazolium (Im) functionalized AEMs increased with the cationic content and only decomposed above 290 °C at high ionic contents. Small angle X-ray scattering of AEMs based on the copolysulfones showed distinct ionomer peaks indicating a characteristic separation distance of ~7 nm. At an ion exchange capacity of 2.2 meq. g-1, the Br- conductivity at 60 °°C reached 6 and 29 mS cm-1 for the QA and Im functionalized AEMs, respectively, despite a similar water content. Thus, the water in the latter membranes was utilized more efficiently for ion transport, possibly because the conjugated Im groups had a higher degree of ion dissociation than the QA groups. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
cationic polyelectrolytes, ionomers, poly(arylene ether sulfones, ion conductivity, fuel cells
in
Journal of Membrane Science
volume
481
pages
164 - 171
publisher
Elsevier
external identifiers
  • wos:000350856400017
  • scopus:84923338272
ISSN
0376-7388
DOI
10.1016/j.memsci.2015.02.002
language
English
LU publication?
yes
id
01d9ffd0-8e57-465b-8959-e0f535d127cf (old id 4940868)
alternative location
http://www.sciencedirect.com/science/article/pii/S037673881500099X
date added to LUP
2015-03-24 22:27:28
date last changed
2017-11-05 03:59:11
@article{01d9ffd0-8e57-465b-8959-e0f535d127cf,
  abstract     = {In order to promote phase separation and properties of anion-exchange membranes (AEMs)we have prepared polysulfones with an exceptionally high local concentration of imidazolium groups. Statistical copolymers containing single dioxyphenylene rings directly functionalized with four cationic groups were synthesized by polycondensations of 4,4’-dichlorodiphenylsulfone, 4,4′-isopropylidenediphenol and tetramethylhydroquinone, followed by complete benzylic bromination and quaternization using N-methylimidazole, as well as trimethyl amine for reference. In contrast to the quaternary ammonium (QA) containing materials, the thermal stability of the imidazolium (Im) functionalized AEMs increased with the cationic content and only decomposed above 290 °C at high ionic contents. Small angle X-ray scattering of AEMs based on the copolysulfones showed distinct ionomer peaks indicating a characteristic separation distance of ~7 nm. At an ion exchange capacity of 2.2 meq. g-1, the Br- conductivity at 60 °°C reached 6 and 29 mS cm-1 for the QA and Im functionalized AEMs, respectively, despite a similar water content. Thus, the water in the latter membranes was utilized more efficiently for ion transport, possibly because the conjugated Im groups had a higher degree of ion dissociation than the QA groups.},
  author       = {Weiber, Annika and Jannasch, Patric},
  issn         = {0376-7388},
  keyword      = {cationic polyelectrolytes,ionomers,poly(arylene ether sulfones,ion conductivity,fuel cells},
  language     = {eng},
  pages        = {164--171},
  publisher    = {Elsevier},
  series       = {Journal of Membrane Science},
  title        = {Polysulfones with highly localized imidazolium groups for anion exchange membranes},
  url          = {http://dx.doi.org/10.1016/j.memsci.2015.02.002},
  volume       = {481},
  year         = {2015},
}