Poly(vinylbenzyl chloride) (PVBC)-grafted poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) films were prepared as precursors for ion-exchange membranes with a radiation grafting technique. A scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDX) instrument was used to investigate the effects of the radiation grafting conditions on the distribution profiles of the grafts in the FEP-g-PVBC films because the properties of the ion-exchange membranes were largely affected not only by the degree of grafting (DOG) but also by the distribution of the graft chain. These results indicate that the distribution profile of the grafts largely depended on the grafting parameters, such as the solvent, monomer concentration, film thickness, and irradiation dose. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 2380-2385, 2010