Stability of sulfonated polytriazole and polyoxadiazole membranes

Abstract

The performance and stability of sulfonated polytriazoles with polymer backbones containing diphenyl ether (S-DPE-PT) and hexafluorisopropylidene groups (S-FPT) were compared, aiming their application as proton conductive membranes for fuel cell. The chemical stability of both membranes were compared and analyzed by infrared spectroscopy after 24 h heating at temperatures up to 250 • C. The superior stability of the fluorinated polytriazole was confirmed. 

Synthesis and fabrication of nanostructured hydrophobic polyazole membranes for low-energy water recovery

“…The synthesis of polyoxadiazole and polytriazole was based on a procedure reported by our group before for related polymers [16][17][18]. For the synthesis of polyoxadiazole, first polyphosphoric acid (PPA) was added to a 250 mL three necked flask and was heated at temperature to 100 1C for 1 h under mechanical stirring along with the passage of dry N 2 gas to ensure the removal of water contents.…”

“…High hydrophobicity, low heat transfer, high thermal stability, and high dimension stability at operation temperature and maximum porosity are the important targeted properties for membrane materials and membranes. We chose a class of materials widely explored in our group for other membrane applications: polyoxadiazoles and polytriazoles [16][17][18][19][20][21]. They are known for their high temperature stability and their synthesis has been optimized to supply high molecular weight polymers with the best film-forming characteristics for membranes.…”

Crosslinked polytriazole membranes for organophilic filtration

“…Polybenzoxazole membranes prepared by thermal rearrangement from polyimide precursors have been successfully explored for gas separation or fuel cell [21,22]. Our group has been investigating fluorinated polyoxadiazoles and sulfonated polytriazoles prepared by polycondensation for fuel cell application [23][24][25] using one-pot polycondensation reactions. We recently reported the direct synthesis of a hydroxyl-functionalized copolyazole, from fluorinated oxadiazole monomers [26].…”

Preparation and evaluation of sulfonated polyoxadiazole membrane containing phenol moiety for PEMFC application

“…Because of the high affinity to water absorption, the wide signal at 2000-3700 cm −1 became wider and more intensive than SPPOD and SCDPPOD. The branching and degradation of diphenyl ether C-O-C bond catalyzed by acid at high temperature which lead to the phenoxy terminated segment formation has been previously reported in literatures [57,[60][61][62]. Also, at high temperatures, protonated oxadiazole groups are degraded and suffer from cleavage, analogous to the mechanism proposed by Franski et al [61].…”

“…Also, at high temperatures, protonated oxadiazole groups are degraded and suffer from cleavage, analogous to the mechanism proposed by Franski et al [61]. This degradation produces some active groups such as amine, amide, carbonyl and others that lead to branching and some partially crosslinking in polymer structure [43,51,57,62]. It seems that when the polyoxadizole was synthesized at high temperatures, some side reactions can take place [57,63,64].…”