Strain induced anisotropies in silica polydimethylsiloxane composites

Schneider, G. J. and Goeritz, D. (2010) Strain induced anisotropies in silica polydimethylsiloxane composites. JOURNAL OF CHEMICAL PHYSICS, 133 (2): 024903. ISSN 0021-9606,

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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. (C) 2010 American Institute of Physics. [doi:10.1063/1.3447919]

Item Type: Article
Uncontrolled Keywords: SMALL-ANGLE SCATTERING; X-RAY-SCATTERING; LOZENGE CONTOUR PLOTS; ELASTIC BEHAVIOR; TOPOLOGICAL CONSTRAINTS; NANOCOMPOSITE MEMBRANES; DYNAMIC PROPERTIES; POLYMER NETWORKS; CARBON-BLACK; NANOPARTICLE;
Subjects: 500 Science > 530 Physics
Divisions: Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Group Dietmar Göritz
Depositing User: Dr. Gernot Deinzer
Date Deposited: 22 Jul 2020 09:07
Last Modified: 22 Jul 2020 09:07
URI: https://pred.uni-regensburg.de/id/eprint/24463

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