Process and Structure Interactions in Polymer Materials: the Case of Non-Isothermal Crystallization Kinetics during Processing
Résumé
The study of the relationship between the material, its structure, its behavior on one hand and its processing conditions on the other hand is a multidisciplinary science. Its modeling requires multiphysical couplings and considerations at various scales: microscopic for the chemical structures of the macromolecules forming the material and macroscopic for the global behavior and the process -- materials interactions. Such studies often require important experimental developments to understand the basic aspects of these interactions, as well as mathematical modeling often inspired by experimental observations. Laboratory experimental conditions are unfortunately not representative of those the material experiences during processing. Mathematical modeling in this case is therefore an essential tool to explore varied or extreme conditions and offers detailed optimization parametric studies of the process -- structure -- properties triangle. The heat transfer during processing of polymeric and/or composites materials plays an important role. The molds are truly heat exchangers that are determinant for the quality of the finished products. Hence, it is necessary to model the mold thermal behavior, taking into account several physical phenomena which occur, due to the interactions between this sort of heat exchanger and the material. In the present work, extensive theoretical developments on the crystallization of polymers under non-isothermal flow are presented. An illustration of the process-structure relationship is proposed through recent theories and the results are dealing with the effect on crystallization kinetics in the case of injection molding of thermoplastic polymers.