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Intrinsically proton-conducting benzimidazole units tethered to polysiloxanes

Persson, Christian LU and Jannasch, Patric LU orcid (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)
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publishing date
type
Contribution to journal
publication status
published
subject
in
Macromolecules
volume
38
issue
8
pages
3283 - 3289
publisher
The American Chemical Society (ACS)
external identifiers
  • wos:000228442100031
  • scopus:17444370931
ISSN
0024-9297
DOI
10.1021/ma047482+
language
English
LU publication?
yes
additional info
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Polymer and Materials Chemistry (LTH) (011001041)
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
2016-04-01 11:53:54
date last changed
2021-09-15 01:39:44
@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 (ACS)},
  series       = {Macromolecules},
  title        = {Intrinsically proton-conducting benzimidazole units tethered to polysiloxanes},
  url          = {http://dx.doi.org/10.1021/ma047482+},
  doi          = {10.1021/ma047482+},
  volume       = {38},
  year         = {2005},
}