Electron-beam (EB)-initiated grafting of triallyl cyanurate (TAC) onto polyethylene (PE) has been carried out over a range of radiation doses (2-20 Mrad) and concentrations of TAC (0.5-3 parts by weight). The grafting level, as determined from IR spectroscopy, is maximum at a 10 Mrad radiation dose using 1 part TAC. With increasing TAC level at a 15 Mrad dose, the grafting level is higher only after 1.5 parts TAC. The gel content increases with radiation dose in the initial stages. X-ray studies indicate two peaks at 10.6-10.8-degrees and 11.7-11.9-degrees and the corresponding interplaner distances of 4.15 and 3.80 angstrom. With increase in radiation dose or TAC level, the crystallinity decreases in the initial stage and then increases. It shows a decreasing trend again at higher radiation dose. The interplanar distance or the interchain distance of the modified polymer does not change. However, the crystallite size increases initially and then decreases. The tensile properties are relatively insensitive to the variation of radiation dose because of the interplay of various factors. The dielectric loss, tan delta, shows a maximum at a 10 Mrad dose and minimum at 5 and 15 Mrad due to changes of polarity and the carrier mobility.