Dresden 2009 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 13: POSTERS Polymer Physics
CPP 13.30: Poster
Tuesday, March 24, 2009, 14:00–16:30, P3
Analysing dielectric interphases in composites containing nano- and micro- particles — •Béatrice Hallouet1, Pauline Desclaux1, Bernd Wetzel2, Alois Schlarb2, and Rolf Pelster1 — 1Universität des Saarlandes, FR 7.2 Experimentalphysik, D-66123 Saarbrücken, Germany — 2Institut für Verbundswerkstoffe GmbH (IVW), Erwin-Schrödinger-Straße Geb.58, D 67663 Kaiserslautern, Germany
We have investigated a molecular relaxation process in a solid polymer filled with dispersed magnetite particles. Especially, we compare systems containing nano-particles with diameters between 20 and 30 nm and micro-particles with diameters between 0.5 and 5 µm. Temperature-dependent broadband dielectric spectroscopy in a frequency range between 50 Hz and 1 GHz reveals that the presence of nano- or micro-particles does not affect the molecular dynamics. However, there is a marked difference in the polymers relaxation strength reflecting both the polarizability and the number of relaxing units. While in the micro-composites the polymer matrix behaves bulk-like, its relaxation strength increases in the nano-composites, the deviation from the bulk value being proportional to the volume fraction of particles. We discuss the results in terms of interphases of thickness δ around particles and agglomerates, the volume fraction of which increases with increasing particle concentration and decreasing particle size. Additional IR and DSC measurements are used to check whether the chemical properties or the amorphous state of the polymer matrix have been altered by the addition of particles.