In this work, low density polyethylene (LDPE) was grafted with trifluoroacetic acid allyl ester using γ-ray irradiation from a Cobalt-60 source at different adsorbed doses. It was found that the grafting degree increases with the absorbed doses. The highest grafting degree was obtained at 100 kGy of absorbed dose and with 30 wt% of trifluoroacetic acid allyl ester. The grafting was identified with fourier transform infrared (FT-IR) using a calibration curve reported in literature. Thermal properties of the functional polymers were studied by thermogravimetric analysis (TGA) and the surface morphology was investigated by scanning electron microscope (SEM).