Theoretical and experimental study of the flow of a molten polymer in a micro-compounder
Résumé
Micro-compounders are more and more used to characterize and optimize the formulations and the flow conditions of complex materials, with very low quantities, around a few grams. These machines are composed of a small-size conical twin-screw extruder, coupled with a recirculating channel, in which the material can be processed during a fixed time and a certain number of cycles, before being purged. However, the precise flow conditions inside these machines are not well known, what makes an optimal interpretation of the results difficult. Therefore, in this paper, a theoretical model based on continuum mechanics is proposed to calculate the flow in the recirculating mode. An experimental study on a well-chosen polymer is carried out to define the influences of the main processing parameters (screw speed, mass of material, barrel temperature) and to validate the model. Despite the simplicity of the theoretical approach, the calculated results are in satisfactory agreement with the experiments.
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