Novel Hyperbranched Polymer-Based Anion-Exchange Membranes

Abstract

Anion-exchange membranes (AEMs) are promising materials for a wide variety of applications including among others, fuel cells, electrolyzers, and membrane separation processes. However, development of AEMs with improved hydroxyl conductivity and selectivity as well as excellent thermo-mechanical stability, remains an absolute necessity, now more urgent than ever, due to the global climate change and energy crisis. The main objective of the present study is to synthesize novel AEMs with excellent hydroxyl conductivity and mechanical stability from hyperbranched polyester polymers. More specifically, poly (vinyl pyridine) (PVP) was grafted onto bis-MPA polyester-64-hydroxyl via graft copolymerization and subsequently quaternized using different alkylating agents. The effects of some variables such as grafting degree and alkylating agent on the morphology as well as on the materials properties of these new-developed membranes were evaluated. The cation stability in alkaline media and the water uptake of these AEMs were also investigated. Some characterization techniques such as NMR, SAXS, FTIR, TEM, TGA, DSC and impedance spectroscopy were used to assess the materials properties of these membranes.