Viscoelastic Modelling of Polymer Melts and Rubber Compounds

Walter Friesenbichler, Sebastian Stieger, Roman Christopher Kerschbaumer, Gerald Berger-Weber, Andreas Neunhäuserer, Evan Mitsoulis

    Research output: Chapter in Book/Report/Conference proceedingConference contribution


    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.
    Original languageEnglish
    Title of host publicationAdvances in Polymer Processing 2020 Christian Hopmann Rainer Dahlmann Eds. Proceedings of the International Symposium on Plastics Technology
    PublisherSpringer Vieweg
    Number of pages12
    ISBN (Electronic)978-3-662-60809-8
    ISBN (Print)978-3-662-60808-1
    Publication statusPublished - 2020

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