Synthesis of side-chain type sulfonated polyimides and the effect of side-chain length on the properties

Tomohiro Yasuda*, Yi Li, Kenji Miyatake, Michiko Hirai, Masato Nanasawa, Masahiro Watanabe

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review


A series of side-chain type polyimide copolymers containing fluorenyl groups (SPI-4) were synthesized for the applications to polymer electrolyte fuel cells (PEFCs). The effect of alkyl chain length on the properties was investigated, where the carbon number of the pendant acidic groups was ranging from 1 to 12. While the obtained SPI-4 (1, 3, 4, 12) gave tough and flexible membranes by casting from the solution, SPI-4 (10) did not give a tough membrane. SPI-4 (1, 3, 4) displayed 10-2 - 100 S/cm of the proton conductivity which was comparable to that of Nafion 112 at 100% RH. However, SPI-4 (10, 10P, 12) displayed much lower conductivity. TG/DTA-MS analyses revealed two step weight losses for all SPI-4 with loss of hydrated water and acidic groups, respectively. Phosphoated SPI-4 (10P) has better thermal stability than the sulfonated analogue. The accelerated hydrolytic testing revealed that the SPI-4 with longer side chains are more hydrolytically stable than those with shorter side chains.

Original languageEnglish
Number of pages2
Publication statusPublished - 2005
Externally publishedYes
Event54th SPSJ Symposium on Macromolecules - Yamagata, Japan
Duration: 2005 Sept 202005 Sept 22


Other54th SPSJ Symposium on Macromolecules


  • Alky1 groups
  • Electrolyte
  • Membrane
  • Phosphoric acid groups
  • Polyimide
  • Side-chain
  • Sulfonic acid groups

ASJC Scopus subject areas

  • Engineering(all)


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