Morpholinium functionalized poly[ethylene pyrrole/ethylene ketone/propylene ketone] membranes prepared through microwave assisted Paal-Knorr reaction for anion conducting membranes

Anion exchange membranes (AEMs) are key components in emerging electrochemical technologies and are attracting increasing interest as alternatives to proton exchange membranes (PEMs). Polyketones have recently emerged as low-cost and easily tunable precursors for AEM fabrication; however, their conventional functionalization through the 1,4-diketonic moieties by convection heating requires prolonged reaction times (48-72 h), limiting process scalability and sustainability.Here, we report a microwave-assisted synthetic strategy to synthesize poly[ethylene pyrrole/ethylene ketone/propylene ketone] with morpholinium groups, achieving complete conversion within 3 h while preserving excellent yields (>95%), representing a significant improvement over the traditional thermal method. Moreover, precise control over the degree of functionalization is guaranteed.The resulting membranes (3MPA-FPKKf(X)g, X = I, OH) were extensively characterized in the anionic form. They exhibited good thermal stability (up to 150 °C), and promising anion conductivity in the hydroxide form (4.5 mS cm−1 at 80 °C). These properties underline the effectiveness of the proposed functionalization strategy and its potential to advance the development of polyketone based materials for ionic conduction applications.