THE NEUMANN-STEFAN PROBLEM AND ITS RECENT WIDENING AS AN ADVANCED TOPIC OF TRANSPORT PHENOMENA

The classical Neumann-Stefan problem (progress of crystallization from a quenched wall) can only be adapted to realistic situations if cryst allization kinetics are introduced. After a review of the theoretical achievements attention is focused on the determination of the kinetic parameters which will enable us to simulate processes in isotactic pol ypropylene numerically, including the prediction of internal structure s such as number (and size) of spherulites per unit volume and transcr ystallization areas near the mold surface. Also with a proper measurem ent of the number of nuclei and of the growth speeds of spherulites as functions of temperature, heat transfer considerations play a key rol e. The influence of flow, which manifests itself in injection-molded p arts by highly oriented surface layers, has separately been treated.