  A large body of experimental work on the microstructure and dynamics of
simplifiedindustrial nanocomposites made of disordered silica filler in a
styrene-butadiene matrixby solid-phase mixing is regrouped and critically
discussed in this feature article. Recentresults encompass systems with varying
polymer mass, grafting functionality, and fillercontent. They have been
obtained by simulation-based structural modelling of nanoparticleaggregate size
and mass deduced from small-angle scattering and transmission
electronmicroscopy. Our model has been validated by independent swelling
experiments.Comparison of structurally-close nanocomposites of widely different
chain mass led tothe identification of a unique structure-determining
parameter, the grafting density, aswell as to a unified picture of aggregate
formation mechanisms in complex nanocompositesduring mixing. In addition,
low-field proton NMR allowed for the characterization ofdynamically slowed-down
('glassy') polymer layers, which were shown not to dominatethe rheological
response, unlike the structural contribution. Finally, broadband
dielectricspectroscopy was used in an innovative manner to identify filler
percolation -- also identifiedby rheology -- via dynamics along filler
surfaces.
