In the work presented the structure of SBR rubber compounds filled wit
h different carbon black grades is investigated by small-angle X-ray s
cattering (SAXS) experiments. Both the surface and the 3-dimensional s
tructure of the aggregates are described with fractal structure concep
ts. The corresponding fractal dimensions depend on the used carbon bla
ck grade. For comparison, the results of three silica-filled samples a
re presented.