Modelling of Mixing in Single Screw Extruders

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Abstract:

Polymer extrusion is one of the most important polymer processing techniques. Modelling of the phenomena developing inside single screw extruders enabled the development of commercial software which can be used to study the performance of existing systems and to define the equipment characteristics for new applications. Although mixing is one of the most important performance measures of extrusion, it is usually disregarded in the available programs. Consequently, in this work mathematical models for quantifying mixing in single screw extruders are developed and subsequently inserted in a global computer modelling program of single screw extrusion. The mixing model quantifies distributive and dispersive mixing and coalescence mechanisms in a liquid-liquid system. This is accomplished by calculating the variation of the thickness of drops considered to be suspended in the polymeric matrix, taking into account the rate and drop break-up time and the coalescence probability. The influence of several parameters, such as viscosities, initial drop dimension, screw speed and barrel temperature, are examined

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Periodical:

Materials Science Forum (Volumes 514-516)

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1409-1413

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May 2006

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© 2006 Trans Tech Publications Ltd. All Rights Reserved

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[1] H.E.H. Meijer, J.M.H. Janssen, Mixing of Immiscible Liquids, In I. Manas-Zloczower, Z. Tadmor, Mixing and Compounding of Polymers, pp.85-147, Hanser Publishers, Germany (1994).

Google Scholar

[2] J. L. White, Polymer Mixing - Technology and Engineering, Hanser Publishers, Germany (2001).

Google Scholar

[3] T. A. Osswald, Polymer Processing Fundamentals, Hanser Publishers, Munich (1998).

Google Scholar

[4] N. Domingues, Modelação Matemática de Mistura em Extrusão de Polímeros, Master Thesis, University of Minho, Guimarães (2004).

Google Scholar

[5] J.M. Ottino, The Kinematics of Mixing: Stretching, Chaos and Transport, Cambridge Univ. Press, UK (1989).

Google Scholar

[6] A. Gaspar-Cunha, Modelling and Optimization of Single Screw Extrusion, PhD Thesis, University of Minho, Guimarães (1999).

Google Scholar

[7] I. Manas-Zloczower, Analysis of Mixing Polymer Processing Equipment, Rheo. Bull. 66, n. º 1, pp.5-8 (1997).

Google Scholar

[8] Y. Renardy, V. Cristini, J. Li, Drop Fragment Distribution under Shear with Inertia, Int. J. Multiphase Flow, n. º 28, pp.1125-1147 (2002).

DOI: 10.1016/s0301-9322(02)00022-8

Google Scholar

[9] H. P. Grace, Dispersion Phenomena in High Viscosity Immiscible Fluid System and Application of Static Mixers as Dispersion Devices in such Systems, Chem. Eng. Comm., 14, pp.27-52 (1982).

DOI: 10.1080/00986448208911047

Google Scholar

[10] Y. W. Stegeman, Time Dependent Behaviour of Droplets in Elongational Flows, PhD Thesis, Technische Univ. Eindhoven, Germany (2002).

Google Scholar

[11] L. A. Utracki, Z. H. Shi, Development of Polymer Blend Morphology During Compounding in a TwinScrew Extruder, Polym. Eng. Sci. 32, n. º 24, pp.1824-1833, (1992).

DOI: 10.1002/pen.760322405

Google Scholar

[12] L. Delamare, B. Vergnes, Computation of Morphological Changes of a Polymer Blend along a Twin-Screw Extruder; Polym. Eng. Sci. 36, n. º 12, pp.1685-1693 (1996).

DOI: 10.1002/pen.10565

Google Scholar