Poly(arylene ether ketone) carrying hyperquaternized pendants: Preparation, stability and conductivity

Abstract

A new strategy to synthesize comb-shaped poly(arylene ether ketone) ionomers with hyperquaternized pendants was detailed in this work. Poly(arylene ether ketone) with electron-rich phenyl rings on the side chain was copolymerized. These electron-rich phenyl rings which could be chloromethylated and serve as precursors to cationic sites, are introduced during monomer synthesis. After chloromethylation and quaternization on the side chain, these resulting anion exchange membranes exhibit high conductivities and good dimensional stability, which benefit from the side chain type structure. The highest chloride conductivity of 0.047 S cm−1 was observed in PAEK-QTPM-30 (IEC = 1.58 mmol g−1) and swelling ratio is 31.7% at 80 °C. The structural properties of the synthesized poly(arylene ether ketone)s were investigated by 1H NMR spectroscopy. The anion exchange membranes showed excellent thermal stability up to 200 °C under nitrogen and good chemical stability for high conductivity after treating in alkaline condition up to 30 days. These membranes were studied by IEC, water uptake, dimensional stability. The nano-phase separation from ionic aggregation was confirmed by SAXS. This work implies a viable strategy to improve the performance of anion exchange membranes.