Title

The Relation Between Microstructure of Thermoplastics, Processing Parameters and Mechanical Properties of Injected Samples

Authorship

VILLOUTREIX, G.; HADDOUT, A.; VILLOUTREIX, J.

VILLOUTREIX, G.

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HADDOUT, A.

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VILLOUTREIX, J.

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DOI

10.5151/2594-5327-49v9-97-108

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Abstract

In injection molding, the quality of manufactured products depends sharply on the choice of injection parameters. Our study deals with the relations between processing parameters (temperature, viscosity...), microstructure of semi-crystalline thermoplastics and mechanical properties of molded samples. These results are relative to virgin isotactic polypropylene (PP) and to the same polymer with nucleating agent (talc) added. A new rheological apparatus specially adapted to injection molding machines allows us to measure the rheological behaviour of virgin and nucleated PP at high industrial shear rates commonly used in injection processing. Optical microscopy analysis allows us to identify typical crystalline structure and show the influence of the molding temperature and of the nucleating agent content. Finally, mechanical and thermomechanical analysis of injected samples lead us to outline the importance of cooling kinetic inside the mold on studied properties.

Keywords

thermoplastics, polypropylene, injection molding, microstructure, mechanical properties