Entwicklung eines Programmes zur Temperaturkorrektur der Scherviskosität und Ermittlung der Dehnviskosität von polymeren Werkstoffen

Translated title of the contribution: Development of a program for temperature correction of shear viscosity and calculation of elongational viscosity for polymers

Martin Rescher

    Research output: ThesisMaster's Thesis

    174 Downloads (Pure)

    Abstract

    The measurement of the shear viscosity of high viscous polymers on the Capillary Rheometer (CR) can lead to high dissipation heating, which can result in a misinterpretation of the received data. In addition a calculation of the elongational viscosity out of the pressure drop in the inlet zone is possible. In both cases a temperature correction of the generated viscosity data is necessary. To describe this phenomenon, an analytic calculation method for the determination of the average melt temperature with consideration of elongational heating by a model of Perko was used. Based on this model a computer program has been developed, which is able to calculate the temperature development in the die by using an iterative calculation. Five material-laws are available for the approximation of the viscosity function. In practical experiments the program was validated. Three different Acrylonitrile Butadiene Rubbers (NBR) were measured autonomously on the CR with a round die setup. In addition data for a Styrene-Butadiene Rubber (SBR) and an Ethylene Propylene Diene Monomer Rubber (EPDM) were taken from preliminary works. It was possible to evaluate all polymers with the new program. It turned out that an adiabatic regime cannot generally be assumed in the round die. Therefore the calculation method of Schuschnigg for the thermic transition regime was implemented into the analysis. With the usage of the Graetz number it was possible to estimate the thermic basic conditions (adiabatic regime, transition regime or equilibrium regime) in the die. Dependent on the concrete regime the correct equation for the specific regime is used. In addition one NBR material was also measured with a slit die setup. Afterwards the measurement of the NBR was compared with the round die setup of the same NBR. With consideration of the heat conductivity in the slit- and round die setup both measurement methods showed a good agreement.
    Translated title of the contributionDevelopment of a program for temperature correction of shear viscosity and calculation of elongational viscosity for polymers
    Original languageGerman
    QualificationDipl.-Ing.
    Supervisors/Advisors
    • Friesenbichler, Walter, Co-Supervisor (internal)
    • Fasching, Michael Andreas, Supervisor (external), External person
    • Perko, Leonhard, Supervisor (internal)
    Award date27 Mar 2015
    Publication statusPublished - 2015

    Bibliographical note

    embargoed until 23-03-2019

    Keywords

    • temperature correction
    • TempCorr
    • round die
    • slit die
    • capillary rheometer
    • CR
    • Injection molding machine rheometer
    • IMMR
    • elongation viscosity

    Cite this