Abstract: AminefunctionalizedPP(PP-g-NH₂)was introduced into PP/nano SiO₂, composites as a reac tive compatibilizer.Itshowed that the  tensile strength, Young's modulus, and notched impact strength of the composites were increased at low nano-silica content. When 3 wt % epoxy functionalized nano-sil- ica and 10 wt% PP-g-NH₂ were used, the tensile strength and notched impact strength of PP can be in-creased by 13 % and 87 %，respectively.

Key words: polypropylene, silica nanoparticle;reactrve compatibilizer, mechanical property