Abstract: Based on in situ radical suspension polymerization, polystyrene nanocomposites were prepared from styrene and nanoinorganic particle. Then, hexane was added to prepare expandable polystyrene nanocomposites (EPSNC). EPSNC were characterized by means of gel permeation chromatography, thermo gravimetric analyzer, and scanning electron microscope. It showed that at a suitable content of nanoinorganic particle, the molecular weight of EPSNC had a narrower distribution, the thermal stability of EPSNC was improved significantly. In addition, the nanoinorganic particle showed a nucleatio

Key words: expandable polystyrene, nano-inorganic particle, in-situ suspension polymerization, micro-morphology