Abstract: Foamed samples of three kinds of PE-HD，including PE-HD 7600M，PE-HD 50005, and PE-HD 5200，and PE-HD/nano-montmorillonite composites were prepared via extrusion foaming. Lrystallization behavior of 7600M，5000S，and 5200B was studied by differential scanning calorimetry (DSC). Density and electron micrographs of the three grades of PE-HD and their nano-OMMT composite foam samples were tested via true density meter and scanning electron microscopy(SEM).The result showed that melt flow rate had effect on the extrusion foaming. The lowest density of the foamed samples was 0. 59 g/cm3 when the resin was 5200B and the content of foaming agent was 2 phr. The foaming effect was enhanced when the melt flow rate of the resin was higher. The addition of nano-montmorillonite improved the extrusion foaming of PE-HDs with higher melt flow rates.

Key words: high density polyethylene, extrusion foaming, foaming system, nano montmorillonite