Rheological Percolation Threshold in High-Viscosity Polymer/CNTs Nanocomposites

Abstract

Polystyrene (PS)/multi-walled carbon nanotubes (CNT) nanocomposites have been prepared through melt mixing processing \naiming at obtaining a uniform and homogeneous dispersion of the used nanoparticles within the polymeric matrix. Optical and scanning \nelectron microscopy has been employed to determine the dispersion and distribution of CNTs at different length scales. Furthermore, the \nlinear viscoelastic behavior of formulated nanocomposites has been deeply investigated. As a result of CNTs added, the nanocomposites \nexperience a transition from liquid-like to solid-like rheological behavior, and a disappearance of relaxation processes at low frequency can be \nnoticed. By plotting G’ versus CNTs loading and fitting with a power-law function, the rheological threshold of PS-based nanocomposites has \nbeen calculated. Moreover, the mechanical behavior of nanocomposites has been investigated and related to the formed CNTs network within \npolymer matrix.