Poly(arylene ether) ionomers containing sulfofluorenyl groups: Effect of electron-withdrawing groups on the properties

Takuya Shimura, Kenji Miyatake, Masahiro Watanabe

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

For polymer electrolyte membrane fuel membrane cell (PEMFC) applications, the effect of electron-withdrawing groups on the properties of sulfonated poly(arylene ether) (SPE) ionomer membranes was investigated. A series of poly(arylene ether)s containing fluorenyl groups and electron-withdrawing groups (sulfone, nitrile, or fluorine) was synthesized, which were sulfonated with chlorosulfonic acid using a flow reactor to obtain the title ionomers. The ionomers had high molecular weight (Mn > 77 kDa, Mw > 238 kDa) and gave tough, ductile membranes by solution casting. The ion exchange capacity (IEC) of the membranes ranged from 1.6 to 3.5 mequiv/g as determined by titration. The electron-withdrawing groups did not appear to affect the thermal properties (decomposition temperature higher than 200 °C). The presence of nitrile groups, especially at positions meta to the ether linkages, improved the oxidative stability of the SPE membranes, while it led to a deterioration of the hydrolytic stability. The perfluorinated biphenylene groups were effective in providing high mechanical strength with reasonable dimensional change, probably due to a somewhat decreased water absorbability. The SPE membrane containing sulfone groups showed the highest proton conductivity (10-3-10-1 S/cm) at 20-93% RH (relative humidity) and 80 °C. The nitrile-containing SPE membrane showed smaller apparent activation energies for oxygen and hydrogen permeability and is thus considered to be a possible candidate for applications in PEMFCs.

Original languageEnglish
Pages (from-to)4054-4062
Number of pages9
JournalEuropean Polymer Journal
Volume44
Issue number12
DOIs
Publication statusPublished - 2008 Dec
Externally publishedYes

Keywords

  • Electron-withdrawing groups
  • Fuel cells
  • Ionomers
  • Poly(arylene ether)s
  • Proton conduction

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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