The Foamed Polypropylene (PP) and polypropylene/inorganic nanoparticles composites samples were prepared with different kinds of inorganic nanoparticles in the same volume expansion ratio using a injection molding machine equipped with volume-adjustable cavity

and the foaming behavior was investigated. It was found that cell structure of pure Polypropylene was deteriorated

however the introduction of inorganic nanoparticles improved the rheological property and crystallization onset temperature of polymer melt

and the cell structure deterioration was suppressed

and the foaming behavior of Polypropylene composites was excellently improved. The results show that the PP/OMMT foamed composite had the best cell morphological structure. The cell diameter and density were 24. 6um and 2 × 10

6

cell/ cm3 respectively.