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Title: Recent results and persisting problems in modeling flow induced coalescence

The contribution summarizes recent results of description of the flow induced coalescence in immiscible polymer blends and addresses problems that call for which solving. The theory of coalescence based on the switch between equations for matrix drainage between spherical or deformed droplets provides a good agreement with more complicated modeling and available experimental data for probability, P{sub c}, that the collision of droplets will be followed by their fusion. A new equation for description of the matrix drainage between deformed droplets, applicable to the whole range of viscosity ratios, p, of the droplets and matrixes, is proposed. The theory facilitates to consider the effect of the matrix elasticity on coalescence. P{sub c} decreases with the matrix relaxation time but this decrease is not pronounced for relaxation times typical of most commercial polymers. Modeling of the flow induced coalescence in concentrated systems is needed for prediction of the dependence of coalescence rate on volume fraction of droplets. The effect of the droplet anisometry on P{sub c} should be studied for better understanding the coalescence in flow field with high and moderate deformation rates. A reliable description of coalescence in mixing and processing devices requires proper modeling of complex flow fields.
Authors:
;  [1]
  1. Institute of Macromolecular Chemistry AS CR, Heyrovského nám. 2, 162 06 Prague 6 (Czech Republic)
Publication Date:
OSTI Identifier:
22270991
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1593; Journal Issue: 1; Conference: PPS-29: 29. international conference of the Polymer Processing Society, Nuremberg (Germany), 15-19 Jul 2013; Other Information: (c) 2014 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COALESCENCE; COMPUTERIZED SIMULATION; DEFORMATION; DIFFERENTIAL EQUATIONS; DROPLETS; ELASTICITY; FLUID FLOW; MATRIX MATERIALS; POLYMERS; PROCESSING; RELAXATION TIME; VISCOSITY