Imidazolium functionalized poly(vinyl chloride-co-vinyl acetate)-based anion exchange membrane

Abstract

Poly(vinyl chloride-co-vinyl acetate) functionalized with the imidazolium cation was synthesized for anion exchange membranes. The chemical structure of the membrane was confirmed by 1H NMR and FTIR analyses. Scanning electron microscopy and thermogravimetric analyses were performed to ascertain the surface and thermal properties of the membrane. The anion exchange membranes were characterized by water uptake, hydroxide ion conductivity, and alkaline stability analyses. The maximum of 11.4% degree modification with the imidazolium cation was achieved with a 1,2-dimethylimidazole/poly(vinyl chloride-co-vinyl acetate) weight ratio of 8:1. The water uptake, ionic conductivity, thermal stability, and alkaline stability were correlated to the degree of imidazolium. The resulting anion exchange membrane exhibited a water uptake capacity of 28% with a hydroxide ion conductivity of 10 mScm−1 at 80 °C. The membranes were thermally stable up to 160 °C. Both the cationic group and the polymer backbone were found to be stable in 1 M KOH solution at 60 °C over 72 h.