Dynamic mechanical analysis (DMA) and scanning electron microscopy(SEM) were used to study the compatibility of nylon6/polystyrene(PA6/PS) blends with poly(styrene-b-ethylene oxide) (PSt-b-PEO) diblock copolymers as compatibilizer. It has been found that the compatibility of the blends prepared by pure PA6 and PS is very poor. The boundary between the phase domains of PA6 and PS without PSt-b-PEO is sharp and clear. When 2 parts of PSt-b-PEO copolymer per hundred of resin(phr) were added

the glass transition temperatures of the constituent polymers converge

the size of the disperased phase domain decreases and the thickness of the interfacial layer increases

because PSt-b-PEO is efficient in lowering the interfacial tension and enhancing the interfacial adhesion in PA6/PS blends.And the compatibilization effects PSt-b-PEO diblock copolymers with different molecular weight and composition ratio on PA6/PS(80/20) blends were also discussed.The compatibilizing efficacy of PSt-b-PEO is dependent on the actual amount of the compatibilizers in the boundary region of PA6/PS blends.When the molecular weight is appropriate and ethylene oxide block length in PSt-b-PEO is more than that of styrene

the compatibilization is more efficient for PA6/PS(80/20) blends.