A Molecular Dynamics Simulation Study of the Mechanical Properties of Carbon-Nanotube Reinforced Nylon 6 Composite

In recent years, polymer/carbon nanotube composites have attracted a lot of attention because the polymer properties are significantly improved. In particular, intensive efforts have been directed toward synthesizing, characterizing and understanding polymer/CNT composites. In this paper, as an effort to explore the effective use of carbon nanotubes as a reinforcing material for advanced nanocomposites with polymer matrix, a single walled carbon nanotube (SWCNT) is used to reinforce Nylon 6 matrix. Molecular dynamics (MD) simulations are used to study two periodic systems - a long CNT-reinforced Nylon 6 composite and amorphous Nylon 6 matrix itself. The axial and transverse elastic moduli of the amorphous Nylon 6 matrix and nanocomposites are evaluated using constant-strain energy minimization method. The results from molecular dynamics simulations are compared with corresponding rule-of-mixture predictions. The simulation results show that CNTs significantly improve the stiffness of Nylon 6/CNT composite, especially in the longitudinal direction of the nanotube. The conventional rule-of-mixture predicts a much larger value than MD simulation for the nanocomposite.