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Preparation and solubility of water–methanol mixtures in sulfonated poly(etherketone) containing a cardo‐ring structure
Author(s) -
Akiba Curato,
Watanabe Kenji,
Nagai Kazukiyo,
Hirata Yuichi,
Nguyen Quang Trong
Publication year - 2006
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.23491
Subject(s) - sulfonic acid , methanol , solubility , polymer chemistry , membrane , sulfuric acid , polymer , aqueous solution , ionomer , materials science , chemistry , organic chemistry , copolymer , biochemistry
The preparation and solubility of water–methanol mixtures in sulfonated (1,3‐dihydro‐3‐oxoisobenzofuran‐1,1‐diyl‐1,4‐phenyleneoxy‐1,4‐phenylenecarbonyl‐1,4‐phenyleneoxy‐1,4‐phenylene) (C‐PEK) was systematically studied. The sulfonation was carried out by reacting C‐PEK with 98% sulfuric acid at 60°C. This reaction obeys a first‐order reaction mechanism up to 4 h. The sulfonic acid group was uniformly dispersed in a sulfonated C‐PEK (SC‐PEK) membrane. The introduction of sulfonic acid groups in C‐PEK could increase polymer segmental gaps because of the size of a bulky sulfonic acid group or decrease polymer segmental gaps as a result of polar interactions. The former effect is dominant for SC‐PEK with low sulfonic acid content, whereas the latter occurs for SC‐PEK with high sulfonic acid content. The uptake of pure water or an aqueous methanol solution (e.g., 3, 5, and 10 wt % methanol concentration) in the sulfonated C‐PEK membranes increases with increasing sulfonic acid group content. However, the sulfonated C‐PEK with high sulfonic acid content selectively sorbs water rather than methanol in the membrane. This suggests that the sulfonated C‐PEK membrane could prevent crossover of methanol through the membrane and has potential as a polymer electrolyte for the direct methanol fuel cell. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1113–1123, 2006