Epoxy-funetionahzed ethylene propylene rubber(gEPR) was prepared in a eomtating twin-screw extruder．The degree of grafting of EPR was determined by FTIR measurements．The ohase structure．fracture morphology

toughening mechanism and mechanical properties of Nylon-6/gEPR blends were studied in detail．The resets show that the epoxy groups of gEPR van react with the carboxyl and (or) amine groups of Nylon-6 and form Nylon-6-co-EPR copoymer

which earl act as compatibilizer to decrease the interfaeial tension between Nylon-6 and EPR

and result in a more uniform dispersion of EPR in the Nylon-6 matrix．At the same time

the particle size of EPR decreases with the increase of the grafting degree of EPR．SEM observation of fracture surfaces indicates that Nylon-6/gEPR blends exhibit fractures of ductile mode

and from the SEM analysis of deformation zones it can be concluded that the cafitation of rubber particles and shear yielding of matrix are the main toughening mechanism．Mechanical tests also show that the addition of gEPR into Nylon-6 matrix improves the Ized no．bed impact strength of Nylon-6 significantly．