Abstract
Recent progress in the filler microstructure and the dynamical properties of polymer nanocomposites of industrial relevance is reviewed. We focus mainly on systems used in car tire treads made of styrene-butadiene rubber (SBR) matrices in which precipitated amorphous silica like Zeosil® with a complex multi-scale structure is dispersedwhile occasionally comparing to other experimental systems, including model studies with well-defined colloidal silica nanoparticles. Electron microscopy and small-angle scatteringnamely SAXS and SANSare powerful methods of structural analysis, and some recent developments including the correlation hole analysis giving access to local aggregate properties, or reverse Monte Carlo approaches providing aggregate distribution functions, are discussed. The dynamical response of such complex systems is then studied by broadband dielectric spectroscopy (BDS), starting from the individual components. Maxwell-Wagner-Sillars interfacial polarization processes including charge and water migration are shown to be able to probe large-scale microstructure, evidencing filler percolation effects as observed in rheology. Then, BDS is shown to be highly suitable for studies of the evolution of the segmental dynamics of rubber, giving insight into vulcanization mechanisms under the effect of industrial additives, as well as in transitions from heterogeneous to homogeneous dynamics of polymer blends. Finally, the difficulties of investigating segmental dynamics in industrially-relevant filled systems by BDS are critically discussed, and some recent neutron spin-echo results are reported evidencing only a small impact of filler surfaces on segmental dynamics in weakly interacting SBR-silica systems.