The Effect of Molecular Weight on Polypropylene Foaming

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OCLC: 1019465349

Abstract

The effect of molecular weight on polypropylene (PP) extrusion foaming was investigated and the process to make soft touch, largely expanded, high cell density non-crosslinked PP foam using environmental friendly CO₂ is presented. In previous research, when the cell density was high, cell opening was dominant and large expansion could not be achieved even in HMS PP materials. The effects of processing and material parameters on the foam morphologies of PP materials with three different melt flow rate (MFR) were studied using single-screw tandem foam extrusion system. By selecting proper material and die, and by tailoring the processing conditions, large expansion (25 fold) and high cell density (>10⁹ cells/cm³) was successfully achieved in the high MFR PP without any additives. The mechanism of locally induced crystallization was found to be significantly affecting the foaming behavior of PP and was successfully verified using SEM, DSC, HPDSC, shear viscosity and solubility measurements.

Cited Works (8)

Year	Entry
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Cited By (1)

Year	Entry
2015	Andalib KMZ. Increasing Void Fraction of the Polypropylene Foams Blown With Chemical Blowing Agents in High Temperature Extrusion [Master's thesis]. University of Toronto; November 2015.