TY  - JOUR
AU  - Schneider, G.J.
AU  - Göritz, D.
TI  - Strain induced anisotropies in silica polydinethylsiloxane composites
JO  - The journal of chemical physics
VL  - 133
SN  - 0021-9606
CY  - Melville, NY
PB  - American Institute of Physics
M1  - PreJuSER-14188
SP  - 024903
PY  - 2010
N1  - 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.
AB  - 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.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:20632772
UR  - <Go to ISI:>//WOS:000279917700033
DO  - DOI:10.1063/1.3447919
UR  - https://juser.fz-juelich.de/record/14188
ER  -