Fe2+ Catalyzed Synthesis of Radiation Grafted Functional Membranes and Application in Fuel Cells and Ion Recovery

Summary: 1-Vinylimidazole is grafted onto Poly(ethylene-alt-tetrafluoroethylen (ETFE) by means of pre-irradiation technique with electron beam doses between 50 and 150 kGy. The degree of grafting is significantly increased to values of up to 115% by addition of 20-50 mmol/L of an Fe²⁺ salt that facilitates the decomposition of the peroxide structures within the irradiated films. The obtained mechanically stable and flexible ETFE-graft-poly(1-vinylimidazole) membranes exhibit a homogenous distribution of the graft polymer for degrees of grafting greater than 50 wt.-% and show thermal stability up to 250 °C. The applicability of these membranes as anhydrous proton conducting material when doped with phosphoric acid and the complexation capability for Cu²⁺ ions is demonstrated.