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Abstract

Rubber-toughened polypropylene (PP) is an important resin for many engineering applications. Through the structural foaming of materials, material cost-saving and lightweight structures can be achieved. In this study, physical blends of PP and poly(ethylene/octene) at various compositions were characterized for their melt strength and shear viscosity. The high pressure MuCell^® foaming process was used to obtain structural foams with average cell diameters of <50 μm and cell densities of approximately 8 million cells/cm³. This study presents key understandings between material rheology and its suitability for structural foaming that are in turn linked to blend composition and melt temperature.

Keywords

foam injection molding polypropylene ethylene/octene copolymer blends viscosity and melt strength.

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Understanding Melt Rheology and Foamability of Polypropylene-based TPO Blends

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