Enhanced thermo-oxidative stability of sulfophenylated poly(ether sulfone)s

Abstract

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. Monophenylated poly(ether sulfone)s (Ph-PES) and diphenylated poly(ether sulfone)s (DiPh-PES), were synthesized as starting materials for the preparation of sulfonated polymers with well-defined chemical structure. Mild post-polymerization sulfonation conditions led to sulfonated Ph-PES (Ph-SPES) bearing acid groups on both the pendant phenyl group and the backbone, and sulfonated DiPh-PES (DiPh-SPES) bearing acid groups only on the two pendant phenyl groups. Both series of polymers had excellent mechanical properties, high glass transition temperatures, good thermal and oxidative stability, as well as good dimensional stability. It is interesting to note that exclusively pendant-phenyl-sulfonated (bissulfophenylated) DiPh-SPES copolymers possessed obviously better thermal and oxidative stability compared with the corresponding pendant-phenyl-sulfonated/main-chain-sulfonated Ph-SPES copolymers. The methanol permeability values of the membranes were in the range of 7.0 Â 10 À7 -9.4 Â 10 À8 cm 2 /s at 30 C, which is several times lower than that of Nafion 117. DiPh-SPES-50 and Ph-SPES-40 also exhibited high proton conductivity (approximately 0.13 S/cm at 100 C).

Ion Transport by Nanochannels in Ion-Containing Aromatic Copolymers

“…It is well-known that pendent phenyl groups are readily sulfonated on polymers 90 and that the resulting sulfophenylated polymers are oxidatively more stable than those sulfonated on the main chain. 91 By using methodology of placing pendent phenyl groups on both the nucleophilic and the electron-deficient monomers, the latent hydrophilic segment can be postsulfonated after copolymerization so that the sulfonic acids are in closer proximity. Thus, sulfonated segmented copoly(arylene ether sulfone)s were synthesized to increase the proximity of sulfonic acid groups in the conducting segment, which were controlled to 15, 30, and 60 (i.e., X = 5, 10, and 20, respectively).…”

A clustered sulfonated poly(ether sulfone) based on a new fluorene-based bisphenol monomer

“…36,38 The improved oxidative stability is attributed to the introduction of the sulfonic acid groups on pendant-phenyl groups on the main 30 chain. 45 …”

“…One of the effective strategies is the design of multiblock PEMs based on hydrophilic and hydrophobic oligomers. [21][22][23][24][25][26][27][28] The sequential block structure of 45 these PEM promotes phase separation between hydrophilic and hydrophobic segments, resulting in much higher proton conductivity being achieved in a reduced humidity environment in comparison with random sulfonated copolymers. Some multiblock PEMs with long hydrophilic and hydrophobic block 50 segments exhibited clear lamellar morphology with wellconnected hydrophilic channels and proton conductivity comparable to that of Nafion 212 at low humidity.…”

Phenyltrimethylammonium Functionalized Polysulfone Anion Exchange Membranes

“…41 If the polymer structure contains flexible pendent side chains linking the polymer main chain and the sulfonic acid groups, nanophase separation between hydrophilic and hydrophobic domains may be improved, thus enhancing proton conductivity and mitigating water swelling. 42−45 While there have been few reports on AEMs based on aromatic polymers with pendent quaternary ammonium (QA) groups, the strategy of utilizing a "side-chaintype" structure is also expected to be useful in AEMs.…”