Effect of CNT Morphology and Alignment on the Interfacial and the Elastic Properties of Nanocomposites

A.R. Alian, S.A. Meguid
University of Toronto,

Keywords: multiscale modeling, molecular dynamics, micromechanics, nanocomposites, carbon nanotubes, orientation, alignment, agglomeration, waviness


Carbon nanotubes (CNTs) are typically curved, agglomerated and aggregated as a result of van der Waal interactions and electrostatic forces. It has been proven experimentally that CNT morphology and alignment affect the mechanical, electrical, and piezoresistive properties of their nanocomposites. Most existing studies assume CNTs to be straight and uniformly dispersed within the polymer matrix. In this work, we investigate the effect of waviness, agglomeration, and alignment of CNTs on the interfacial and elastic properties of CNT-reinforced epoxy composites. Two aspects of the work were conducted. In the first, MD simulations of a numerical pull-out test were carried out of CNTs, with different curvatures and bundle diameters, fully embedded in an epoxy resin to evaluate the corresponding interfacial shear strength (ISS). In the second, the elastic moduli of the considered CNT-epoxy composites were determined using multiscale modelling. The multiscale simulations were carried out using molecular dynamics to determine the atomic-level elastic coefficients of a representative volume element and micromechanics (Mori-Tanaka) to scale up the obtained RVE’s nanoscale properties. The results of our study reveal that waviness, agglomeration, and alignment are key parameters that dictate the interfacial and the elastic properties of CNT-reinforced polymer nanocomposites.