Analysis of dispersive mixing processes in polymer melts

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Thermoplastic polymers are much more multipurpose applicable as metals, ceramics and other organic and anorganic materials. This high application potential is based on their thermoplastic processibility at comparatively low temperatures and on their simple modificability in order to obtain application specific properties (addition of particles or droplets and functional components, generation of blends with defined morphology). The homogeneity of the melt is the most important criteria for product quality in compounding and processing. Basic knowledge for description and quantifying of material homogeneity in complex material systems like polymer blends and with additives modified polymer compounds are less developed. For that reason continuum mechanical fundaments shall be elaborated for mixing processes in this research project. The pseudo plastic flow behavior and viscoelastic properties of the polymer melt influence dispersive mixing processes. The numerical simulation of the flow in wedge - rectangular - slit (WRS) applying finite - difference - methods (FDM) gives the possibility elongation and shear strains to calculate for droplet deformation and breakage, critical stresses for droplet break to determine and criteria to define optimized design and process parameters for dynamic mixing systems.The aim of the research project is to calculate the superimposed planar elongation and shear flow for high viscos, pseudo plastic and viscoelastic polymer melts in WRS, which represents the basic element of dispersive mixing shear units. Detailed representations of local elongation and shear strains, local elongation and shear rates, local normal and shear stresses and local residential times of melt particles shall giveinformation from working and efficiency of dispersive mixing shear units. The simulation program can be used than as tool for design and optimaizing of dispersive mixing geometries.The results of the FDM - simulation must be verified experimentally. A special designed experimental device shall be developed and build in order to inject small high viscos melt droplets in to the main flow the lower viscos second melt at the area of the entry section of the shear unit. Droplet deformation and breakage shall be analyzed, quantified and with calculated values compared.