Novel anion exchange membrane with low ionic resistance based on chloromethylated/quaternized‐grafted polystyrene for energy efficient electromembrane processes
A novel anion-exchange membrane has been manufactured by chloromethylation and subsequent quaternization of polystyrene within a graft copolymer films based on UV-oxidized polymethylpentene. Particular attention is given to the kinetics of chloromethylation and the influence of the reaction conditions on the properties of the anion-exchange membranes. By means of variation of the polystyrene content and its crosslinking degree we have obtained membranes that have an ion-exchange capacity from 1.1 to 2.9 mmole g−1, anion transport numbers between 91.0 and 95.5% and specific ionic conductivities (σ25 Cl− Þ ranging from 2 to 25 mS cm−1. The developed membranes due to their low thickness and high conductivities have a remarkably low surface ionic resistance of around 0.6 Ωcm2. It was calculated that the use of the developed materials will increase the efficiency of reverse electrodialysis energy production by 8–10% compared to the state of the art membranes.