Polypropylene Characteristics in Extrusion Foaming Process at Low Pressure
Amir Husin, Rahul Gupta, Sati N. Bhattacharya, Andro Lau
RMIT University
Australia

Keywords: Polypropylene, Foam extrusion, Foam density

---

This paper presents the characteristics of high melt strength polypropylene in extrusion foam process at low pressure (up to 800 psi). The polypropylene was extruded through a single screw extruder with carbon dioxide as the blowing agent. The effects of the key parameters such as temperature, pressure, extrusion speed and blowing agent against foam cell morphology were evaluated. It was concluded that the foam density was significantly affected by these key parameters. It was observed that very low foam density could be achieved in extrusion foaming at low pressure. However, the generated cell size was in the range of millimeter. The cell density, foam density and strand diameter showed a proportional relationship. It was also observed that when the foam density increased, the cell density also increased while the strand diameter decreased.