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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 8: Poster: Nanoparticles and Composite Materials

CPP 8.33: Poster

Montag, 26. März 2012, 17:30–20:00, Poster A

Investigation of interphases in polyethylenepropylene(PEP)-silsesquioxane-nanocomposites by positron annihilation lifetime spectroscopy — •Christian Ohrt¹, Tönjes Koschine¹, Stephan Harms¹, Klaus Rätzke¹, Franz Faupel¹, Gerald Schneider², Lutz Willner², and Dieter Richter² — ¹Materialwissenschaft-Materialverbunde , Universität Kiel, 24143 Kiel — ²Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich

Free volume studies were performed in polymer-nanocomposites by positron annihilation lifetime spectroscopy (PALS) to explore the influence of the interphase nanoscale character of the filler particles and the nanoscale particle size on positron parameters. A weakly repulsive system was obtained by mixing of poly(ethylene-alt-propylene) (PEP) and silsesquioxane nanoparticles with varying concentration. DSC experiments showed a constant glass transition temperature Tg of the polymer and a phase transition of the filler at low temperature. PALS measurements showed a constant glass transition temperature Tg of the polymer, an increase of the free volume at the phase transition of the filler and a strong drop of the thermal expansion coefficient above Tg with increasing filler concentration. By changing the composition of the samples and applying a simple mixing rule for the lifetime spectra of the ortho-positronium, information about the existence of an interphase with properties different from the polymer matrix could be obtained.