Ethanol dimethyl ammonium functionalized poly[ethylene pyrrole/ethylene ketone/propylene ketone] anion exchange membranes for alkaline electrochemical devices

This study reports the synthesis of new anion exchange membranes (AEMs) based on poly[N-{N′-(2′-hydroxyethyl)-N′,N′-dimethylammoniumethyl}-ethylenepyrrole(X)/(ethyleneketone)/ (propyleneketone)] (E-FPKK_f(X)_g) with X = I⁻ or OH⁻, obtained by modulating the degree of functionalization (f). The synthesis of these AEMs involves the reaction of poly[ethylene ketone/propylene ketone] with 2-(2-aminoethylamino)ethanol using a Paal-Knorr chemistry. The physical-chemical characteristics of these membranes are extensively analyzed by elemental analysis (CHNS/O), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), high resolution thermogravimetric analysis (HR-TGA) and modulated differential scanning calorimetry (MDSC). The electrical behavior is examined using broadband electric spectroscopy (BES), demonstrating conductivities of 1.66 and 0.084 mS cm⁻¹ 30 °C for the membranes in the hydroxide and iodide form, respectively. Additionally, the stability tests conducted by immersing the membranes in 1 M KOH solution at ambient temperature for 336 h reveal promising chemical resistance in alkaline conditions for the membranes in hydroxide form.