Recent advances in structural and dynamical properties of simplified industrial nanocomposites

摘要

A large body of experimental work on the microstructure and dynamics of simplified industrial nanocomposites made of disordered silica filler in a styrene-butadiene matrix by solid-phase mixing is regrouped and critically discussed in this feature article. Recent results encompass systems with varying polymer mass, grafting functionality, and filler content. They have been obtained by simulation-based structural modelling of nanoparticle aggregate size and mass deduced from small-angle scattering and transmission electron microscopy. Our model has been validated by independent swelling experiments. Comparison of structurally-close nanocomposites of widely different chain mass led to the identification of a unique structure-determining parameter, the grafting density, as well as to a unified picture of aggregate formation mechanisms in complex nanocomposites during mixing. In addition, low-field proton NMR allowed for the characterization of dynamically slowed-down ('glassy') polymer layers, which were shown not to dominate the rheological response, unlike the structural contribution. Finally, broadband dielectric spectroscopy was used in an innovative manner to identify filler percolation- also identified by rheology- via dynamics along filler surfaces. (C) 2016 Elsevier Ltd. All rights reserved.