doi:10.3850/978-981-08-7619-7_P006

ABSTRACT

Polymer nanocomposites are of interest because they may provide a way to design composite materials with greatly enhanced properties at relatively low volume fractions of the included phase. One underlying mechanism, thought to contribute to these properties is the presence of an interfacial region, ~ 15 nm thick, between the polymer matrix and included particles. The size of the interface makes relatively little contribution to the effective properties of composites with micro-sized particles, but because its size is comparable to the size of the nano-scaled included phase, its potential impact on nanocomposites is much greater. In particular, percolated nanomicrostructures may result at volume fractions below theoretical thresholds, due to connectivity achieved through rod-interface-rod, or `pseudo-percolation', contact. In this work the influence of the interface layer is incorporated into estimates of critical volume fraction through an excluded volume model. Results show a significant reduction in the range of critical volume fractions. These values are incorporated in a mechanical percolation model and used within a mean-field micromechanics model to predict effective properties of the nanocomposite.

Keywords: Nanocomposites, Percolation, Excluded volume, Micromechanics.

© 2011 RPS