Study on Continuous Extrusion Foaming of PP/PS/Nano-clay with Supercritical CO_2

The PP/PS/nano-clay blend was foamed in this paper using a single-screw continuous extruder system and cell structure of foamed samples was characterized with the aid of SEM.By comparing cell morphology,foam expansion ratio,cell density and cell diameter,etc,the effect of blend ratio for R-PP/PS/nano-clay blend on cell morphology of foamed samples was studied.The results showed foaming behavior of PP could be improved when it was blended with PS,and the addition of nano-clay further improved the foaming property of the blends.With the increase of nano-clay content,the average diameter of cell decreased and cell density increased.Microcellular foamed plastics with cell density as high as 2.16×108 cells/cm3 were obtained when 5 wt% nano-clay was included in the formulation.