Berlin 2001 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 16: Poster: Dynamics of Molecular Systems, Polymer Dynamics, Glass Transition, Crystallization, Electronic Properties of Polymers

CPP 16.13: Poster

Monday, April 2, 2001, 12:30–15:00, AT1

Effect of dissolved small molecules on the internal friction of polycarbonate — •Ole Hölck, I. Böhm, P. Pekarski, H.G. Brion, and R. Kirchheim — Institut für Materialphysik, Universität Göttingen, Hospitalstr. 3-7, 37073 Göttingen

The solution of small molecules in polycarbonate causes an additional relaxation peak. This peak was recently studied by means of mechanical spectroscopy and was attributed to the jumps of the solute molecules within the polymer matrix [1]. In analogy to the effects of carbon atoms in α-iron it is referred to as Snoek peak. With the aid of a specially constructed vibrating-reed-apparatus we are able to investigate the internal friction spectra of polymers at frequencies of about 100-1000 Hz. These data, combined with those acquired earlier [1] with a torsion-pendulum at low frequencies, give information about activation energy and strength of the Snoek relaxation process. The measured width of the Snoek peak indicates the significance of the distribution of site energies for the solute molecules. The comparison of diffusion coefficients with those acquired by volumetric techniques allow us to discuss the nature of the jump process involved.

[1]: I.Böhm, H.G.Brion, R.Kirchheim: Polymer 41 (2000) 6613-6617.