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Cristallisation et transferts thermiques dans un polymère thermoplastique semi-cristallin en refroidissement rapide sous pression

Abstract : An accurate description of the heat transfer is essential in the simulation and optimization of processes, the quality of semicrystalline thermoplastic parts is strongly linked to the thermal history during the formatting. Reliable results require a fine knowledge of the thermophysical properties of the polymer. The objective of this work is to develop experimental devices associated with identification methods to measure the thermal properties and crystallization kinetics of polymer under the material forming conditions. A measurement protocol and the identification of thermal properties and crystallization kinetics of polypropylene by inverse methods under low pressure and low cooling rate has been developed in a first study. Then, a new PvT device running up to 400 ° C and 200 MPa has been designed and experimentally validated. The thermal conductivity and the crystallization kinetics were measured under high cooling rate and high pressure. A luminance sensor combining an optical fiber and a photodetector has been set up on a device of the laboratory in order to measure the surface temperature of a polypropylene and thus to identify its crystallization kinetics under high cooling rate. The sensor has been experimentally calibrated and validated. The last part deals with the thermoplastic injection process by presenting a methodology for identifying the kinetics of crystallization from the pressure measurement.
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https://tel.archives-ouvertes.fr/tel-00880924
Contributor : Xavier Tardif <>
Submitted on : Thursday, November 7, 2013 - 10:05:07 AM
Last modification on : Tuesday, July 2, 2019 - 3:04:37 PM

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  • HAL Id : tel-00880924, version 1

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Xavier Tardif. Cristallisation et transferts thermiques dans un polymère thermoplastique semi-cristallin en refroidissement rapide sous pression. Thermique [physics.class-ph]. Université de Nantes, 2012. Français. ⟨tel-00880924⟩

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