Grafting of pre-irradiated poly(ethylene-alt-tetrafluoroethylene) films with styrene: influence of base polymer film properties and processing parameters

The radiation grafting method is of interest for the preparation of ion-exchange membranes for electrochemical and other applications. Typically styrene is used in this method because the grafted polystyrene can be readily modified to introduce a variety of functionalities. The grafting of poly(ethylene-alt-tetrafluoroethylene), or ETFE, films with styrene by the pre-irradiation method has been investigated and compared to that of poly(tetrafluorethylene-co-hexafluoropropylene), or FEP, and poly(vinylidene fluoride), or PVDF. The influence of base polymer film properties such as film thickness, extent of orientation, and molar mass on the grafting behavior of ETFE films is reported. Film orientation was found to often have a dominant influence either directly, as in the case of monoaxially oriented films, or indirectly, as a result of the film extrusion process. In addition, the effects of the irradiation type and atmosphere and grafting temperature on the grafting behavior of one ETFE film type were examined in more detail.