Facile self-crosslinking to improve mechanical and durability of polynorbornene for alkaline anion exchange membranes

Crosslinking is a valid approach to enhance the mechanical and durability performance of anion exchange membranes (AEMs). Herein, a facile and effective self-crosslinking strategy, with no need for an additional crosslinker or a catalyzer, is proposed. A series of tunable self-crosslinking and ion conduction polynorbornene membranes are designed. The 5-norbornene-2-methylene glycidyl ether (NB-MGE) component which affords self-crosslinking enhances dimensional stability, while the flexible 5-norbornene-2-alkoxy-1-hexyl-3-methyl imidazolium chloride (NB-O-Im(+)Cl(-)) hydrophilic unit contributes high conductivity. The crosslinking significantly decreases the water uptake, and water swelling ratio provides excellent solvent-resistance and enhances the thermal and mechanical properties. Additionally, crosslinked rPNB-O-Im-x AEMs exhibit desirable alkaline stability. Impressively, the rPNB-O-Im-30 (IEC = 1.377) shows a moderate ion conductivity (61.8 m S cm(-1), 80 degrees C), with a suppressed water absorption and 88.17% initial OH- con- ductivity is maintained after treated for 240 h with a 1.0 M NaOH solution at 60 degrees C. Suitably assessed of rPNB-O-Im-30 AEM reveals a 98.4 mW cm(-2) peak power density reached at a current density of about 208 mA cm(-2). The report offers a facile and effectual preparative technique for preparing dimensional and alkaline stable AEMs for fuel cells applications. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.