Effects of single adatom and Stone-Wales defects on the elastic properties of carbon nanotube/polypropylene composites: A molecular simulation study

Abstract

Molecular dynamics (MD) simulations were implemented to investigate the effect of single adatom (SA) and Stone-Wales (SW) defects on the longitudinal elastic properties of unidirectional carbon nanotube (CNT)/polypropylene (PP) composites. The longitudinal Young's moduli of individual CNTs and CNT/PP composites were calculated from uniaxial tension simulations, and the interfacial shear strengths (IFSSs) between CNTs and PP matrix were also extracted. The moduli of SA and SW defected CNT/PP composites decrease with the increase of the defect degree, and SW defects have a greater impact on the moduli than SA defects. Moreover, the intrinsic moduli of the CNTs with SA and SW defects also decrease due to the structural relaxations under tension loading as the defect degree increases. However, the IFSSs of SA and SW defected CNT/PP composites tardily decrease and increase with the increase of the defect degree, respectively. Analysis of the parametric loss ratios indicates that the longitudinal elastic properties of SA and SW defected CNT/PP composites strongly depend on that of the CNTs, and the variation of interfacial bonding characteristics caused by SA and SW defects might have a negligible effect.