Strain induced anisotropies in silica polydinethylsiloxane composites

Schneider, G.J.; Göritz, D.

doi:10.1063/1.3447919

Journal Article

PreJuSER-14188

Strain induced anisotropies in silica polydinethylsiloxane composites

Schneider, G. J.FZJ* ; Göritz, D.

2010
American Institute of Physics Melville, NY

The journal of chemical physics 133, 024903 (2010) [10.1063/1.3447919]

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Please use a persistent id in citations: http://hdl.handle.net/2128/19491 doi:10.1063/1.3447919

Abstract: Structural changes of silica in polydimethylsiloxane rubber induced by external forces were studied by means of small-angle X-ray scattering experiments. The silica fraction varies from 9 up to 23 vol% and the elongation ratio from 1 to 3. Within the q-range of 0.02 nm(-1)<q<1 nm(-1) the primary particles and the clusters which consist of these basic units could be resolved. The scattering diagrams of the samples without external deformation are radially symmetric and, in particular, the mass fractal dimension does not depend on the silica fraction. Due to the deformation the contours of the two-dimensional scattering diagrams become elliptic. A model independent analysis of the intensity as a function of the q-vector perpendicular and parallel to the deformation axis revealed that the microscopic cluster size is systematically increased by the macroscopic external deformation. In particular, the deformation ratio at the microscopic and the macroscopic length scale is very similar. The mass fractal dimension, as obtained by the slope of the scattering curve, increases significantly with growing deformation ratio, but is the same in vertical and horizontal directions. A simple relation derived for the crossover from self-similar to self-affine fractals can be used to relate the cluster sizes perpendicular and parallel to the deformation and the mass fractal dimension. By that means, it is demonstrated that the mean number of particles within each aggregate is constant, although the rubber was stretched up to a factor of 3.

Keyword(s): J

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Physics, Atomic, Molecular & Chemical

Note: We gratefully acknowledge the help of Dr. Heise, Universitat Ulm, Ulm, Germany, for supplying the tensile unit and supporting the experiments. We thank Sabine Cunis for the technical support of the SAXS experiments. Providing beam time and financial support of the experiments by the HASYLAB/DESY is gratefully acknowledged. We kindly thank, Leverkusen, Germany, for supplying the samples.

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Appears in the scientific report 2010

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OpenAccess