Structure–property correlations of sulfonated polyimides. I. Effect of bridging groups on membrane properties

Abstract

A series of six‐membered sulfonated polyimides were synthesized using 1,4,5,8‐naphthalenetetracarboxylic dianhydride, 4,4′‐diaminobiphenyl 2,2′‐disulfonic acid as the sulfonated diamine, and various nonsulfonated diamine monomers having different bridging groups. These bulky bridging groups have the capacity to increase hydrolytic stability and proton conductivity. Polyimides with bulky bridging groups showed increased solubility but exhibited lower thermal stability. The ion exchange capacity and water uptake reduced with increase in the bulkiness of the bridging group. This was attributed to the increase in the molecular weight of the repeating unit and hence effectively reduced the sulfonic acid content. In low temperatures, the conductivity was lower than Nafion®115 and, with increase in temperature, the conductivity rapidly increased and exhibited better conductivity than Nafion®115. Polyimides with bulky bridging groups 4‐amino phenyl sulfone, and 2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane showed higher conductivity than other polyimides and Nafion®115 despite low ion exchange capacity. The hydrolytic stability of the polyimides with bulky bridging groups was higher than the polyimides with less bulky atoms because of the imparted flexibility. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3612–3620, 2004

Using silica nanoparticles for modifying sulfonated poly(phthalazinone ether ketone) membrane for direct methanol fuel cell: A significant improvement on cell performance

“…One attractive class of alternatives for Nafion ® is sulfonated high performance condensation polymers, including poly(arylene ether ketones) [2][3][4][5], poly(arylene ether) [6,7], poly(arylene ether sulfones) [8][9][10], and polyimides [11][12][13][14]. These polymers were prepared from both direct polymerization of sulfonated monomers and post-sulfonation on polymer chains.…”

On the Development of Naphthalene-Based Sulfonated Polyimide Membranes for Fuel Cell Applications

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Preparation of cationic latent initiators containing imidazole group and their effects on the properties of DGEBA epoxy resin

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