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Mechanical responses in the length direction and thickness direction of quaternary 1,4‐diazabicyclo‐[2.2.2]‐octane polysulfone alkaline anion‐exchange fuel‐cell membranes
Author(s) -
Zhang Zhennan,
Su Huiyu,
Tian Chenyao,
Qi Rongrong,
Wang Xu,
Xia Re
Publication year - 2019
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.47696
Subject(s) - nanoindentation , materials science , creep , composite material , membrane , polysulfone , viscoelasticity , proton exchange membrane fuel cell , nafion , relative humidity , ultimate tensile strength , chemistry , polymer , thermodynamics , biochemistry , physics , electrode , electrochemistry
A quaternary 1,4‐diazabicyclo‐[2.2.2]‐octane polysulfone (QDPSU) alkaline anion‐exchange fuel‐cell membrane was synthesized. Nanoindentation and uniaxial tension methods were used to test the mechanical properties of this membrane in both the thickness direction and length direction at 26°C and 40% relative humidity. We found that the QDPSU membrane exhibited remarkable viscoelastic properties with significant loading rate‐dependent behavior and time‐dependent behavior (creep–relaxation). The value of compression creep rates and compression relaxation rates of the QDPSU membrane were measured to be about 0.2 by a spherical indenter and changed very little with different holding loads. Compared with Nafion, a most widely used fuel‐cell membrane, the QDPSU alkaline anion‐exchange membrane showed a better creep resistance. During the nanoindentation fatigue test, the variation of depths with the indentation cycles were divided into a rising primary region, a steady‐state secondary region, and a continuous declining region. This was different from the uniaxial tension fatigue test. The cross‐scale and cross‐direction mechanical study from this work will help provide new evidence for bridging the gap between nanoindentation and uniaxial tensile testing. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47696.