Berlin 2005 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 5: SYMPOSIUM: Dynamics of multi-component fluids POSTER

CPP 5.16: Poster

Freitag, 4. März 2005, 17:15–19:00, Poster TU D

Correlation between Morphology and Rheology of Mica-Filled Polyethylene — •Albrecht Kuelpmann, Maged A. Osman, and Ulrich W. Suter — ETH Zurich, Institute of Polymers, 8093 Zurich, Switzerland

This contribution deals with the rheological behavior of mica-filled HDPE melts and its correlation to the microstructure of the composites. A method was developed to measure in-plane and out-of-plane shear properties of these transversely isotropic composites experimentally. To describe the microstructure of the composites, the size and aspect ratio distribution of the dispersed platelets were determined from SEM micrographs by image analysis. The orientation of the particles was obtained from X-ray rocking curve measurements. The elastic reinforcement by the platelets was described by the Halpin-Tsai equation and yielded a reinforcement parameter as a function of the aspect ratio and the orientation. At low shear frequencies, the relative storage modulus exhibited a frequency dependence with increasing filler loading. Relaxation time spectra revealed that these viscoelastic effects were due to an increased relaxation strength at long relaxation times. The extend of these viscoelastic effects scaled with the volume specific surface area rather than size or aspect ratio of the particles. These findings supported a bridging mechanism between particles by polymer.