Grafting of 1‐Vinylimidazole onto Pre‐Irradiated ETFE Films

Abstract 1‐Vinylimidazole (1VIm) was grafted onto poly(ethylene‐alt‐tetrafluoroethylene) (ETFE) films via an electron beam pre‐irradiation technique employing doses from 50 to 150 kGy. The effect of the volume fraction of the monomer in water (ϕ), the irradiation dose and the concentration of a Fe2+ salt additive on the degree of grafting (d.o.g.) were studied. The homogeneity of the graft profile was probed by confocal laser scanning microscopy (CLSM) and evaluated by means of a uniformity parameter U. It was found that addition of 50 mmol · L−1 of FeSO4 · 7H2O allows high d.o.g. values of up to ca. 120% with homogenous depth profiles achieved for d.o.g. greater than 50%. The resulting membranes turn out to be mechanically stable and flexible and endure temperatures of up to 250 °C without significant weight loss. magnified image