Modeling of structure development during polymer processing

The general context of this paper is introduction of a crystallization model into 3D software dedicated to a thermomechanical description of the injection-molding process. From the Kolmogoroff-Avrami-Evans equation for overall kinetics and from additional assumptions on nucleation, a system of differential equations is derived for quiescent crystallization and extended to flow-induced crystallization. The experiments done to identify the relevant crystallization parameters are then described, and the values of these parameters are optimized using the Genetic Algorithm inverse method. To check the validity of the theoretical model and the accuracy of our experimental characterization, the curves calculated for the evolutions of the transformed volume fraction and of the number of spherulites are compared to the experimental ones. Finally, the crystallization model is implemented in the Rem3D® code and some typical calculations are presented.