title: Correlation of mass fractal dimension and cluster size of silica in styrene butadiene rubber composites.
abstract: The morphology of the precipitated silica VN3 filled in styrene butadiene rubber was studied as a function of the volume fraction Φ by means of small-angle X-ray scattering experiments. The wide q-range of 0.008 nm(-1)<q<1 nm(-1) probes the structures of the primary particles, the clusters, and resolves a part of the larger clusters of the silica. The diameter of the primary particles and their surface roughness are independent from the silica concentration. The size of the clusters and the corresponding aggregation number depend on Φ. This observation could be ascribed to external mechanical forces because of the mixing process and to growing cluster-cluster interactions with increasing filler fraction. In contrast the mass fractal dimension does not depend on Φ, and by that means experimentally proving that there is not necessarily a correlation between the mass fractal dimension and the cluster size.
authors.affiliation: Institut für Festkörperforschung, Neutronscattering and Jülich Centre for Neutron Science, Forschungszentrum Jülich, 52425 Jülich, Germany. g.j.schneider@fz-juelich.de
authors.forename: Gerald Johannes
authors.initials: GJ
authors.lastname: Schneider
authors.forename: V
authors.initials: V
authors.lastname: Vollnhals
authors.forename: K
authors.initials: K
authors.lastname: Brandt
authors.forename: S V
authors.initials: SV
authors.lastname: Roth
authors.forename: D
authors.initials: D
authors.lastname: Göritz