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Polysulfones tethered with benzimidazole

Persson, Christian LU ; Josefsson, Karl and Jannasch, Patric LU (2006) In Polymer 47(4). p.991-998
Abstract
Benzimidazole units have been grafted onto a polysulfone (PSU) backbone via long alkyl thio–ether chains using a two-step procedure. In the first step, lithiated PSU was reacted with 10-undecenoyl chloride to graft PSU with undecenoyl side chains. The second step involved a free-radical thiol–ene coupling reaction between the C=C bonds of the pendant undecenoyl chains and 2-(2-benzimidazolyl)ethanethiol. In this reaction, all the C=C bonds were converted into thio–ether linkages without any detectable structural degradation, as confirmed by 1H NMR spectroscopy and size-exclusion chromatography. The procedure constitutes a convenient and general pathway to attach functional or mesogenic groups to PSU via long flexible spacers.... (More)
Benzimidazole units have been grafted onto a polysulfone (PSU) backbone via long alkyl thio–ether chains using a two-step procedure. In the first step, lithiated PSU was reacted with 10-undecenoyl chloride to graft PSU with undecenoyl side chains. The second step involved a free-radical thiol–ene coupling reaction between the C=C bonds of the pendant undecenoyl chains and 2-(2-benzimidazolyl)ethanethiol. In this reaction, all the C=C bonds were converted into thio–ether linkages without any detectable structural degradation, as confirmed by 1H NMR spectroscopy and size-exclusion chromatography. The procedure constitutes a convenient and general pathway to attach functional or mesogenic groups to PSU via long flexible spacers. Thermogravimetry showed that the benzimidazole-functionalized polymers were stable up to 250 °C under nitrogen atmosphere, and that the first degradation step was attributed to the cleavage of the thio–ether bond. While the grafting of the undecenoyl side chains was found to significantly decrease the glass transition temperature (Tg), the subsequent tethering of the benzimidazole only slightly increased the Tg of the grafted PSU backbone. The concentration of benzimidazole was probably too low for the formation of a percolating benzimidazole domain. This explains the quite modest proton conductivity measured under completely dry conditions, e.g. 34 nS/cm at 180 °C for a polymer functionalized with 1.7 benzimidazole units per repeating unit of PSU. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Polymer
volume
47
issue
4
pages
991 - 998
publisher
Elsevier
external identifiers
  • wos:000235522900007
  • scopus:32044475421
ISSN
0032-3861
DOI
10.1016/j.polymer.2005.12.077
language
English
LU publication?
yes
id
5aebe27b-7944-4132-8caa-805e73085d10 (old id 153088)
date added to LUP
2007-07-13 15:39:45
date last changed
2019-05-14 02:59:26
@article{5aebe27b-7944-4132-8caa-805e73085d10,
  abstract     = {Benzimidazole units have been grafted onto a polysulfone (PSU) backbone via long alkyl thio–ether chains using a two-step procedure. In the first step, lithiated PSU was reacted with 10-undecenoyl chloride to graft PSU with undecenoyl side chains. The second step involved a free-radical thiol–ene coupling reaction between the C=C bonds of the pendant undecenoyl chains and 2-(2-benzimidazolyl)ethanethiol. In this reaction, all the C=C bonds were converted into thio–ether linkages without any detectable structural degradation, as confirmed by 1H NMR spectroscopy and size-exclusion chromatography. The procedure constitutes a convenient and general pathway to attach functional or mesogenic groups to PSU via long flexible spacers. Thermogravimetry showed that the benzimidazole-functionalized polymers were stable up to 250 °C under nitrogen atmosphere, and that the first degradation step was attributed to the cleavage of the thio–ether bond. While the grafting of the undecenoyl side chains was found to significantly decrease the glass transition temperature (Tg), the subsequent tethering of the benzimidazole only slightly increased the Tg of the grafted PSU backbone. The concentration of benzimidazole was probably too low for the formation of a percolating benzimidazole domain. This explains the quite modest proton conductivity measured under completely dry conditions, e.g. 34 nS/cm at 180 °C for a polymer functionalized with 1.7 benzimidazole units per repeating unit of PSU.},
  author       = {Persson, Christian and Josefsson, Karl and Jannasch, Patric},
  issn         = {0032-3861},
  language     = {eng},
  number       = {4},
  pages        = {991--998},
  publisher    = {Elsevier},
  series       = {Polymer},
  title        = {Polysulfones tethered with benzimidazole},
  url          = {http://dx.doi.org/10.1016/j.polymer.2005.12.077},
  volume       = {47},
  year         = {2006},
}