Effects of CO<inf>2</inf> and talc contents on recyclable HMS PP foaming

Abstract

Recyclable high-melt-strength (HMS) PP has been introduced as an alternative choice to replace crosslinked material in a tandem foaming extrusion process. A filamentary die was selected to promote the optimum processing condition. The cell nucleation and volume expansion behaviors have been investigated as a function of the aspects of die temperature, CO2 content, and talc content. The results exhibited a significant relationship between the processing parameters and foaming behaviors. Low density (i.e., 12~14 fold), fine-celled (i.e., 107-109 cells/cm 3) PP foams were successfully produced using a small amount of talc (i.e., 0.8 wt%) and 5 wt% CO2.