Viscoelastic Modelling of Polymer Melts and Rubber Compounds

  • Walter FriesenbichlerEmail author
  • S. Stieger
  • R. Kerschbaumer
  • G. Berger-Weber
  • A. Neunhaeuserer
  • E. Mitsoulis
Conference paper


Thermoplastic melts and rubber compounds are viscoelastic fluids. They show a complex flow behavior, which is influenced by various factors such as polymer type, molar mass distribution, recipe, filler-filler network and in some cases wall slippage. Most of the state-of-the-art simulation software packages use viscous material models for the calculation of the flow field as well as pressure and temperature distribution, neglecting the viscoelastic nature of polymers. This simplification may lead to an underestimated pressure demand in injection molding simulation.

This contribution presents how to correctly measure viscosity data (shear and extensional viscosity) for thermoplastics and rubber compounds taking into account the pressure dependency of the viscosity and the influence of viscous dissipation in capillary rheometry at higher shear rates. Moreover, a guideline on how to best fit rheological data with the viscoelastic K-BKZ/Wagner model is outlined. Comparing CFD simulation results to experimental data, only the K-BKZ/Wagner model is able to correctly predict pressure losses of contraction flow dominated geometries. Examples will be given for NBR and PP-PNC.


Polymer melt Viscoelasticity K-BKZ/Wagner model Injection pressure 



This research work was supported by the Austrian Research Promotion Agency (FFG) as part of the “RubExject II” project (corresponding project number 855873) and the company partners SKF Sealing Solutions Austria GmbH, Judenburg, Austria, IB Steiner, Spielberg, Austria and ELMET Elastomere Produktions- und Dienstleistungs-GmbH, Oftering, Austria. The authors further thank company PKT Praezisions-kunststofftechnik Buertlmair Gesellschaft m.b.H. and Prof. T. Lucyshyn, Dr. Ivica Duretek, MSc Stephan Schuschnigg and Dr. Matthias Haselmann for their respective contributions.


  1. 1.
    Fasching, M.: Robust processing in rubber injection molding using advanced simulation methods and material data. Dissertation, Montanuniversitaet Leoben (2015)Google Scholar
  2. 2.
    Mitsoulis, E.: 50 Years of the K-BKZ Constitutive Relation for Polymers. ISRN Polym. Sci. 1–22 (2013)CrossRefGoogle Scholar
  3. 3.
    Ansari, M., Hatzikiriakos, S.G., Mitsoulis, E.: Slip effects in HDPE flows. J. Non-Newtonian Fluid Mech. (2011)Google Scholar
  4. 4.
    Ansari, M., Zisis, T., Hatzikiriakos, S.G., Mitsoulis, E.: Capillary flow of low-density polyethylene. Polym. Eng. Sci. 52, 649–662 (2012)CrossRefGoogle Scholar
  5. 5.
    Konaganti, V.K., Derakhshandeh, M., Ebrahimi, M., Mitsoulis, E., Hatzikiriakos, S.G.: Non-isothermal extrudate swell. Phys. Fluids 28, 123101 (2016)CrossRefGoogle Scholar
  6. 6.
    Mitsoulis, E.: Effect of Viscoelasticity in Fountain Flow of Polyethylene Melts. Int. Polym. Proc. 24, 439–451 (2009)CrossRefGoogle Scholar
  7. 7.
    Mitsoulis, E., Battisti, M., Neunhäuserer, A., Perko, L., Friesenbichler, W., Ansari, M., Hatzikiriakos, S.G.: Flow behaviour of rubber in capillary and injection moulding dies. Rubber Compos. 46, 110–118 (2017)CrossRefGoogle Scholar
  8. 8.
    Mitsoulis, E., Battisti, M., Neunhäuserer, A., Perko, L., Friesenbichler, W.: Flow behavior of PP-polymer nanocomposites in injection molding hyperbolical dies. Adv. Polym. Technol. 1–11 (2018)Google Scholar
  9. 9.
    Lucyshyn, T.: Simulation report for a thin-walled bushing for company PKT Praezisionskunststofftechnik Buertlmair Gesellschaft m.b.H. Institute of Polymer Processing, Montanuniversitaet Leoben (2016)Google Scholar
  10. 10.
    Perko, L., Fasching, M., Friesenbichler, W.: Model for the prediction of bulk temperature changes and pressure losses in rubber compounds flowing through conical dies: An engineering approach. Polym. Eng. Sci. 55, 701–709 (2014)CrossRefGoogle Scholar
  11. 11.
    Cogswell, F.N.: Converging flow of polymer melts in extrusion dies. Polym. Eng. Sci. 12, 64–73 (1972)CrossRefGoogle Scholar
  12. 12.
    Perko, L., Friesenbichler, W., Obendrauf, W., Buchebner, V., Chaloupka, G.: Elongational viscosity of rubber compounds and improving corresponding models. Adv. Prod. Eng. Manag. 8, 126–133 (2013)CrossRefGoogle Scholar
  13. 13.
    Binding, D.: An approximate analysis for contraction and converging flows. J. Non-Newtonian Fluid Mech. 27, 173–189 (1988)CrossRefGoogle Scholar
  14. 14.
    Sentmanat, M.L., Rheol, M.L.: Miniature universal testing platform: from extensional melt rheology to solid-state deformation behavior. Acta 43, 657 (2004)CrossRefGoogle Scholar
  15. 15.
    ANSYS Inc.: ANSYS Polyflow User’s Guide: Release 18.2: Canonsburg, PA, USA (2017)Google Scholar
  16. 16.
    Wagner, M.H.: A constitutive analysis of uniaxial elongational flow data of low-density polyethylene melt. J. Non-Newtonian Fluid Mech. 4, 39–55 (1978)CrossRefGoogle Scholar
  17. 17.
    Leblanc, J.: Rubber–filler interactions and rheological properties in filled compounds. Prog. Polym. Sci. 27, 627–687 (2002)CrossRefGoogle Scholar
  18. 18.
    Payne, A.R.: The dynamic properties of carbon black-loaded natural rubber vulcanizates. Part I. J. Appl. Polym. Sci. 6, 57–63 (1962)CrossRefGoogle Scholar
  19. 19.
    Friesenbichler, W., Berger, G., Fasching, M.: Simulation of Rubber Injection Molding – Challenges and Limitations. Conference Proceedings of the 7th bi-annual International Conference of Polymer & Molds Innovations (PMI). Gent 2016. pp. 179–183Google Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2020

Authors and Affiliations

  • Walter Friesenbichler
    • 1
    Email author
  • S. Stieger
    • 1
  • R. Kerschbaumer
    • 2
  • G. Berger-Weber
    • 1
  • A. Neunhaeuserer
    • 1
  • E. Mitsoulis
    • 3
  1. 1.Institute of Injection Moulding of PolymersLeobenAustria
  2. 2.Polymer Competence Center Leoben GmbHLeobenAustria
  3. 3.School of Mining Engineering and MetallurgyNational Technical University of AthensZografouGreece

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