Blends of low-density polyethylene (LDPE) and poly(ethylene terephthalate) (PET) were prepared with different weight compositions with I plasticorder at 240 degrees C at a rotor speed of 64 rpm for 10 min. The physicomechanical properties of the prepared blends were investigated with special reference to the effects of the blend ratio. Graft copolymers, that is, LDPE-grafted acrylic acid and LDPE-grafted acrylonitrile, were prepared with gamma-irradiation. The copolymers were melt-mixed in various contents (i.e., 3, 5, 7, and 9 phr) with a LDPE/PET blend with a weight ratio of 75/25 and used as compatibilizers. The effect of the compatibilizer contents on the physicomechanical properties and equilibrium swelling of the binary blend was investigated. With an increase in the compatibilizer content LIP to 7 phr, the blend showed an improvement in the physicomechanical properties and reduced equilibrium swelling in comparison with the uncompatibilized one. The addition of a compatibilizer beyond 7 phr did not improve the blend properties my further. The efficiency of the compatibilizers (7 phr) was also evaluated by studies of the phase morphology (scanning electron microscopy) and thermal properties (differential scanning calorimetry and thermogravimetric analysis). (c) 2008 Wiley Periodicals, Inc.