Radiation induced grafting of styrene divinylbenzene onto radiation crosslinked F46 films

Radiation induced grafting of styrene/divinylbenzene onto radiation crosslinked F46 (polytetrafluoroethylene-hexafluopropylene) films in the gaseous phase was carried out to develop the radiation induced grafting technique and improve the quality of obtained F46 ion exchange membranes. The radiation crosslinking process was conducted under following conditions: Dose 3 x 106 rad to 7.5 x 109 rad; temperature, 200 ∼ 230 deg C; and the pressure 4 pa. and 10-3 ∼ 10-5 pa. Thus obtained crosslinked F46 films have a tensile strength of 180∼240 kg/cm2. After annealing the radiation crosslinked F46 films were irradiated again with dose about an order of magnitude less than that for crosslinking. Results indicated that the crosslinked F46 films brought about the increase of melting point, and after which a high elastic region was observed. Furthermore, grafting in gaseous phase caused less homopolymer in the system, and the quality of obtained F46 ion exchange membranes might be improved. At the same time, the consumption of monomer was much decreased