FUNDAMENTALS OF TEXTURING - CRYSTALLIZATION BY HEAT-TRANSFER AND FLOW

The textures which are obtained in crystallizing materials, are strong ly dependent on the processes of casting (flow and heat transfer). It is very important to discern between two extreme limiting cases, viz. the heat conduction controlled processes (occurring with fast crystall izing materials and thick samples) and the nucleation rate controlled processes (occurring with slowly crystallizing materials and thin samp les). Clearly, polymer processing must be classified near the latter l imiting case. In principle, the mathematical problems were solved by W . Schneider et al. in the course of an Austrian National Working Party . But, the evaluation of the physical data is a cumbersome task. A bri ef report is given of the (partial) unravelling of the crystallization kinetics of isotactic PP under the influence of shear flow.