Mixture Rules for Critical Shear Values of Extruded Linear PE/Branched PE Blends |
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Authors: | O Bartoš J David P Filip |
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Affiliation: | 1. Faculty of Technology Technical , University Nám. , TGM 275, 762 72 , Zlín , Czech Republic;2. Institute of Hydrodynamics Academy of Science of the Czech Republic , Podbabskd 13, 166 12 , Prague 6, Czech Republic |
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Abstract: | Oscillatory flow and elastic turbulence belong to the types of flow instabilities frequently encountered during extrusion of polymer melts. The onset of these defects corresponds to the flow conditions when the critical shear stresses or the critical shear rates are attained. The critical values of shear stresses and shear rates were experimentally determined for linear polyethylene/branched polyethylene blends (IPE/bPE) that were prepared with various weight ratios. Consequently, mixture rules of the logarithmic type are proposed. These rules relate the critical value of shear stress (shear rate) of blend to the critical values of shear stresses (shear rates) of the individual pure components, weight fractions, and interaction parameters. There is a good agreement between the proposed mixture rules and experimentally determined critical values. |
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Keywords: | PVC blends N-p-tolylmaleimide thermal properties rheological behavior |
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