Synthesis and characterization of a long side-chain double-cation crosslinked anion-exchange membrane based on poly(styrene-b-(ethylene-co-butylene)-b-styrene)

By choosing a triple block polymer , poly(styrene- b -(ethylene- co -butylene)- b -styrene) (SEBS), as the backbone and adopting a long side-chain double-cation crosslinking strategy, a series of SEBS-based anion-exchange membranes (AEMs) was successively synthesized by chloromethylation , quaternization , crosslinking, solution casting , and alkalization. The 70C16-SEBS-TMHDA membrane showed high OH − conductivity (72.13 mS/cm at 80 °C) and excellent alkali stability (only 10.86% degradation in OH − conductivity after soaking in 4-M NaOH for 1700 h at 80 °C). Furthermore, the SR was only 9.3% at 80 °C and the peak power density of the H 2 /O 2 single cell was up to 189 mW/cm 2 at a current density of 350 mA/cm 2 at 80 °C. By introducing long flexible side chains into a polymer SEBS backbone, the structure of the hydrophilic–hydrophobic microphase separation in the membrane was constructed to improve the ionic conductivity . Additionally, network crosslinked structure improved dimensional stability and mechanical properties .