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Intrinsically proton-conducting benzimidazole units tethered to polysiloxanes

Persson, Christian LU and Jannasch, Patric LU (2005) In Macromolecules 38(8). p.3283-3289
Abstract
Polysiloxanes with pendant benzimidazole units have been prepared by free radical thiolene coupling reactions of 2-(2-benzimidazolyl)ethanethiol and vinyl-functional polysiloxanes. The latter polymers were prepared by anionic ring opening copolymerization of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclosiloxane and 1,3,5-hexamethyleyclosiloxane. Copolymers with different degrees of benzimidazole functionality were conveniently obtained by varying the monomer ratios. The coupling reaction was found to be very efficient, and the vinyl groups were completely consumed, as confirmed by NMR and FTIR spectroscopy. The glass transition temperature (T-g) of the benzimidazole functional copolymers increased dramatically with the benzimidazole content... (More)
Polysiloxanes with pendant benzimidazole units have been prepared by free radical thiolene coupling reactions of 2-(2-benzimidazolyl)ethanethiol and vinyl-functional polysiloxanes. The latter polymers were prepared by anionic ring opening copolymerization of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclosiloxane and 1,3,5-hexamethyleyclosiloxane. Copolymers with different degrees of benzimidazole functionality were conveniently obtained by varying the monomer ratios. The coupling reaction was found to be very efficient, and the vinyl groups were completely consumed, as confirmed by NMR and FTIR spectroscopy. The glass transition temperature (T-g) of the benzimidazole functional copolymers increased dramatically with the benzimidazole content at low contents to reach a plateau value just above 50 degrees C at a content of approximately 33 mol% benzimidazole functional siloxane residues in the copolymer. Conductivity measurements carried out at 60 and 140 degrees C indicated that the level of polymer segmental mobility, and thus the Tg, was the most decisive parameter for the proton conductivity at low temperatures (60 C), while the benzimidazole concentration was more important at elevated temperatures (140 degrees C). A conductivity of 7 x 10(-6) S/cm was reached at 140 degrees C by a polysiloxane carrying 57 mol% benzimidazole-grafted siloxane residues under completely anhydrous conditions. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Macromolecules
volume
38
issue
8
pages
3283 - 3289
publisher
The American Chemical Society
external identifiers
  • wos:000228442100031
  • scopus:17444370931
ISSN
0024-9297
DOI
10.1021/ma047482+
language
English
LU publication?
yes
id
cc1e3146-b8f4-40c9-afb2-aa978b338572 (old id 153059)
alternative location
http://pubs.acs.org/cgi-bin/abstract.cgi/mamobx/2005/38/i08/abs/ma047482+.html
date added to LUP
2007-07-13 15:41:16
date last changed
2017-01-01 04:38:48
@article{cc1e3146-b8f4-40c9-afb2-aa978b338572,
  abstract     = {Polysiloxanes with pendant benzimidazole units have been prepared by free radical thiolene coupling reactions of 2-(2-benzimidazolyl)ethanethiol and vinyl-functional polysiloxanes. The latter polymers were prepared by anionic ring opening copolymerization of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclosiloxane and 1,3,5-hexamethyleyclosiloxane. Copolymers with different degrees of benzimidazole functionality were conveniently obtained by varying the monomer ratios. The coupling reaction was found to be very efficient, and the vinyl groups were completely consumed, as confirmed by NMR and FTIR spectroscopy. The glass transition temperature (T-g) of the benzimidazole functional copolymers increased dramatically with the benzimidazole content at low contents to reach a plateau value just above 50 degrees C at a content of approximately 33 mol% benzimidazole functional siloxane residues in the copolymer. Conductivity measurements carried out at 60 and 140 degrees C indicated that the level of polymer segmental mobility, and thus the Tg, was the most decisive parameter for the proton conductivity at low temperatures (60 C), while the benzimidazole concentration was more important at elevated temperatures (140 degrees C). A conductivity of 7 x 10(-6) S/cm was reached at 140 degrees C by a polysiloxane carrying 57 mol% benzimidazole-grafted siloxane residues under completely anhydrous conditions.},
  author       = {Persson, Christian and Jannasch, Patric},
  issn         = {0024-9297},
  language     = {eng},
  number       = {8},
  pages        = {3283--3289},
  publisher    = {The American Chemical Society},
  series       = {Macromolecules},
  title        = {Intrinsically proton-conducting benzimidazole units tethered to polysiloxanes},
  url          = {http://dx.doi.org/10.1021/ma047482+},
  volume       = {38},
  year         = {2005},
}