Proprietes rheologiques en cisaillement et en elongation d'un polypropylene charge de fibres de verre courtes (French text)

The mechanical and thermal properties of short filled reinforced thermoplastics can be advantageously compared to those of metals. Those composites are characterized by the orientation and distribution state of their fibers. This internal structure affects strongly the final material properties. It is induced by the flow history resulting from processing conditions. For this reason the rheological behavior of these kinds of material must be understood in order to control their fabrication and the product properties. Unfortunately, the characterization of rheological behavior is difficult because of the heterogeneous state and concentration level in fibers.; The aim of the present work is to study the rheological behavior of short glass fibers filled polypropylene. To do so an online slit die rheometer mounted on an injection press was developed. The results obtained from this new rheometer were associated with standard rheological measurements techniques.; From the measured pressure drop in the on line rheometer the elongational was estimated by Cogswell and Binding method. (Abstract shortened by UMI.)...