Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 48: (Hydro)gels and Elastomers

CPP 48.2: Vortrag

Freitag, 15. März 2013, 10:00–10:15, H39

Local chain deformation and stress distributions in strained elastomers — Maria Ott¹, Roberto Pérez-Aparicio², Horst Schneider¹, Paul Sotta², and •Kay Saalwächter¹ — ¹Institut f. Physik-NMR, Martin-Luther-Univ. Halle-Wittenberg, Betty-Heimann-Str. 7, D-06120 Halle, Germany — ²Laboratoire Polymères et Matériaux Avancés, CNRS/Rhodia, Saint Fons, France

Macroscopic strain applied to elastomeric networks induces changes in the orientation fluctuations of the chain segments [1]. This effect can be used to study the local stretching of elastically active chains by suitable NMR methods [2]. Importantly, the method also reveals inhomogeneities, i.e., distributions in local stress, which is particular relevant for elastomers filled with (nano)particles. We have studied a series of natural rubber samples with different cross-link densities and amounts of filler particles. The data is incompatible with predictions of the well-established affine-Gaussian model [3], but can be reproduced on the basis of more recent treatments of the local deformation based upon the tube and phantom models. For the first time, we demonstrate the existence of matrix overstrain in commercially relevant filled elastomers in agreement with simple hydrodynamic predictions.

[1] J.-U. Sommer et al., Phys. Rev. E 78, 051803 (2008)

[2] K. Saalwächter, Prog. Nucl. Magn. Reson. 51, 1-35 (2007)

[3] P. Sotta, B. Deloche, Macromolecules 23, 1999-2007 1990)