A cross-linked fluorinated poly (aryl ether oxadiazole) s using a thermal cross-linking for anion exchange membranes

Abstract

A novel cross-linked fluorinated poly (aryl ether oxadiazole) s having diallyl methylimidazole groups (FPAEO-DA-x) membranes were prepared via copolymerization, bromination, solution casting and hydroxide exchanging using a thermal cross-linking method. The membrane materials synthesized via copolymerization of 2,5-bis(2,3,4,5,6-pentafluorophenyl)-1,3,4-oxadiazole (FPOx) and diallyl bisphenol A (DABPA), bromination of the allyl and imidazolidation with N-methylimidazole (NMI). The anion exchange membranes (FPAEO-DA-x) were obtained by solution casting method, followed by hydroxide exchanging in sodium hydroxide solution and cross-linked by using the thermal cross-linking method. The chemical structures and properties of the cross-linked FPAEO-DA-x membranes (CFPAEO-DA-x) were studied. The highest ionic conductivity of the CFPAEO-DA-x membrane was achieved at 1.94 × 10−2 S cm−1 at 20 °C. Its swelling ratio and TGA properties revealed their good mechanical and thermal stability.