Highly Stable Membranes of Poly(phenylene sulfide benzimidazole) Cross-Linked with Polyhedral Oligomeric Silsesquioxanes for High-Temperature Proton Transport

Marco Viviani, Sebastiaan Pieter Fluitman, Katja Loos, Giuseppe Portale*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

4 Citations (Scopus)
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Abstract

Poly(phenylene sulfide benzimidazole) has been synthesized and tested as a potential material for high-temperature proton transport. A high content of sulfide bonds has been implemented in the polymer chains to endow a high antioxidant capacity and, in combination with bulky benzimidazole pendant units, to significantly suppress crystallinity and thereby improve the solubility in highly polar aprotic solvents. The amorphous polymer has high thermal stability and high glass transition temperature (Tg). Freestanding, insoluble, and robust membranes were obtained via thermal cross-linking of the benzimidazole moieties with octa-glycidyl polyhedral oligomeric silsesquioxane (g-POSS). The series of hybrid networks (cPPSBi_X, with X being the g-POSS content wt %) showed excellent oxidative stability, with cPPSBi_15 having weight loss lower than 5% after 264 h in Fenton's reagent at 80 °C. Elastic moduli as high as 868 MPa with reduced strain at break (1.8%) were obtained. After doping the membranes with phosphoric acid, proton conductivity in the range of 2.3 × 10-2 S cm-1 at 180 °C was obtained, and the membranes show a stress at break of 2.3 MPa. Dimensional and mechanical stability were maintained also at high doping levels thanks to the inclusion of g-POSS which provides the resulting hybrid networks with increased free volume and high cross-link density.

Original languageEnglish
Pages (from-to)7873-7884
Number of pages12
JournalACS Applied Energy Materials
Volume3
Issue number8
DOIs
Publication statusPublished - 24-Aug-2020

Keywords

  • high-temperature polymer electrolyte membrane (HT-PEM)
  • anhydrous proton conductivity
  • oxidative stability
  • hybrid composites
  • cross-linked membranes
  • benzimidazole
  • POSS
  • POLYMER ELECTROLYTE MEMBRANE
  • POLYBENZIMIDAZOLE MEMBRANES
  • PHOSPHORIC-ACID
  • FUEL-CELLS
  • CONDUCTING MEMBRANES
  • DEGRADATION
  • PERFORMANCE
  • STABILITY
  • LINKING
  • BLENDS

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