Authors Mistri, E. A. ; Banerjee, S. ; Komber, H. ; Voit, B.
Title Structure-property correlation of semifluorinated 6-membered co-SPIs for proton exchange membrane
Date 01.12.2015
Number 47385
Abstract This article reports the synthesis, characterization and proton exchange membrane (PEM) properties of four new structurally different naphthalenetetracarboxylic dianhydride (NTDA)-based semifluorinated sulfonated copolyimides (co-SPIs) containing heterocyclic groups as well as phenyl ring with various catenation angles. To understand the structure–property correlation, the co-SPIs were prepared with a fixed sulfonation degree (70%, IEC ~ 2.1) by using the fixed molar feed ratio of sulfonated diamine to the different non-sulfonated diamines. The structures of the different co-SPIs, namely, p-DTN70, m-DTN70, DPyN70, and DThN70 were confirmed by FTIR and NMR spectroscopy. All the co-SPIs showed high thermal stability for 5% weight loss temperature (290–300 °C) in synthetic air. Transparent, flexible and membranes were prepared from the co-SPIs that showed tensile strength in the range of 50–65 MPa and Young`s modulus values in the range of 1.6–1.84 GPa in wet condition. It was noticed that the dimensional and oxidative stability were higher for para-connecting co-SPI membrane (p-DTN70) than for meta-connecting membranes (m-DTN70, DPyN70 and DThN70). Whereas, the proton conductivity was found highest for meta-connecting m-DTN70 membrane (s = 79.2 mS/cm at 90 °C) due to the higher water uptake and better phase separated morphology of the membrane as observed by transmission electron microscopy analysis.
Publisher European Polymer Journal
Citation European Polymer Journal 73 (2015) 466-479
Tags semifluorinated sulfonated polyimides proton exchange properties structure–property correlation

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