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CPP: Chemische Physik und Polymerphysik

CPP 11: POSTER Disperse Polymer Systems

CPP 11.36: Poster

Dienstag, 28. März 2006, 17:00–19:00, P3

Free volume from positron lifetime spectroscopy and mechanical properties of EPDM rubber/SiO₂ nanocomposites — •Jan Kruse¹, Rodrigo Lima de Miranda¹, Klaus Rätzke¹, Matthias Adler², Dirk W. Schubert², and Franz Faupel¹ — ¹Lehrstuhl für Materialverbunde, Universität Kiel — ²Freudenberg Forschungsdienste KG, Weinheim

The addition of inorganic particles to a polymer matrix has a long tradition in polymer engineering. Decreasing their size to nanometre dimensions provides a high specific interaction surface and the possibility of a fine dispersion of the particles. In gas sealing applications, the particles might act as a permeation barrier by blocking diffusion paths (tortuosity). We have investigated EPDM rubber with up to 23 wt% nonfunctionalised SiO₂ nanoparticles. Positron annihilation lifetime spectroscopy (PALS) is a powerful tool to determine free volume from size dependent ortho-positronium lifetime. PALS shows just a slight decrease in free volume element size, but a linear decrease in free volume concentration (from o-Ps intensity) with filler amount. Dynamic mechanical thermal analysis (DMTA) was employed to observe the increase in elastic and damping modulus as well as the respective transition temperature.