Free-radical melt grafting of the multi-monomre system of maleic anhydride(MAH)/styrene(St) onto ABS resin was studied using a Hakke rheometer The maximum MAH graft degree was obtained when the molar ratio of MAH to St was approximately 1：1．The addition of St

an assisting monomer

improved the grafting reactivity of MAH．and St also reacted with MAH to form the St-MAH copolymer(SMA) before the two monomers grafted onto BAS．The site of grafting is mainly at the double bonds of ABS．ABS-g-(MAH-co-St) was used as a precursor on in-situ compatibilizer for incompatible blend of PA6 and ABS．The changes in morphologies of PA6/ABS／ABS-g-(MAH-co-St) blends with different contents of ABS-g-(MAH-co-St) were investigated using SEM．The addition of ABS-g-(MAH-co-St) markedly improved the morphologies of the blends

and an uniform and fine dispersed phase was obseved whh size being about 0.1μm for a PA6/ABS-g-(MAH-co-St)(70/30) blend．The addition of ABS-g-(MAH-co-St) also greatly improved the mechanical properties of PA6/ABS blends．The Izod impact strength of the blends greatly increased with increasing the content of ABS-g-(MAH-co-St) in the blends

and the tensile strength of the blends also incresed The PA6/ABS blends with balanced mechanical properties could be obtmned by addition of ABS-g-(MAH-co-St).