Epoxy-modified polyethylene (PE-g-GMA) was successfully synthesized from glycidyl methacrylate (GMA) and low-density polyethylene (LDPE) via the grafting reaction of extrusion. The mechanism of grafting reaction and the rapid determination for the percentage of grafting are also reported. Experimental results demonstrated that the PE-g-GMA is a good compatibilizer in polyphenylene sulfide/poly(ethylene terephthalate) (PPS/PET) as well as PPS/nylon 6,6/glass fiber alloys and the addition of PE-g-GMA into PPS alloys may effectively improve the mechanical properties of composites. (C) 2008 Elsevier Ltd. All rights reserved.