Rheometer-independent description of the wall slip behaviour of rubber compounds
Final Report Abstract
Due to their complex composition, rubber compounds are prone to flow anomalies such as wall slippage, which require material-specific characterization using appropriate test methods. However, wall-slip boundary conditions are often neglected, both in rheological material characterization and in the numerical flow simulations that build on it to realistically model processing. In addition, state-of-the-art wall-slip correction methods often lead to physically implausible results for rubber compounds. The aim of this research project was to develop a rheometer-independent method for describing wall slip behavior. It was shown that the wall slip behavior of rubber compounds depends on the flow channel geometry of the rheometer and can be described by the COULOMB slip model, while the shear history during the extrusion process has negligible influence on the wall slip behavior. The results led to the further development of an analytical model to describe wall slip effects, which can be used, for example, in numerical flow simulations to improve their validity. It was also shown that the empirical COX-MERZ relationship is not applicable to rubber compounds, while continuous rotational measurements allow an estimation of the expected flow behavior.
Link to the final report
https://oa.tib.eu/renate/handle/123456789/21151
Publications
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Wall Slip-Free Viscosity Determination of Filled Rubber Compounds Using Steady-State Shear Measurements. Polymers, 15(22), 4406.
Kleinschmidt, Dennis; Brüning, Florian & Petzke, Jonas
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A critical review of the applicability of the Cox- Merz Relationship on filled Rubber Compounds. Kautschuk Gummi Kunststoffe, Ausgabe 06/2024
KLEINSCHMIDT, D.; BRÜNING, F. & PETZKE, J.
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Applicability of empirical rheological transfer functions on filled rubber compounds. Proceedings of the Deutsche Kautschuk Tagung (DKT) 2024, Nürnberg (Deutschland), 2024
KLEINSCHMIDT, D.; BRÜNING, F. & PETZKE, J.
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Improvement of an alternative method for the correction of wall slip effects in rheological studies of filled rubber compounds. Universidad de los Andes.
Kleinschmidt, Dennis; Petzke, Jonas & Brüning, Florian
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Influence of pre-shearing on the rheological properties of filled rubber compounds. 15th Fall Rubber Colloquium, Hannover (Deutschland), 2024
KLEINSCHMIDT, D. & BRÜNING, F.
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Wall Slip-Free Measurement of the Steadystate Shear Viscosity of Filled Rubber Compounds Using a Closed Cavity Rheometer. Proceedings of Annual Technical Conference of the Society of Plastics Engineers (ANTEC), St. Louis (USA), 2024
KLEINSCHMIDT, D.; BRÜNING, F. & PETZKE, J.
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Characterization of the wall slip behavior of filled rubber compounds considering the critical wall shear stress. RubberCon 2025, Stockholm (Schweden), 2025
KLEINSCHMIDT, D. & BRÜNING, F.
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Influence of pre-Shearing on the rheological Properties of filled Rubber Compounds. Kautschuk Gummi Kunststoffe, Ausgabe 03/2025
KLEINSCHMIDT, D. & BRÜNING, F.
