Effect of CNT structural defects on the mechanical properties of CNT/Epoxy nanocomposite

Highlights: • Epoxy based RVEs including continuous CNTs with TSW and vacancy defects were constructed through curing process. • Despite weakening effects on the isolated CNTs, the defects enhance the mechanical properties of the RVEs. • The interactions between polymer and defected sites improve the load transfer in the interface. • Due to the CNT kinking, higher load is needed to pull out the defected CNTs. - Abstract: The mechanical behavior of epoxy-based nanocomposite in the presence of pristine single wall carbon nanotube (SWCNT) and the SWCNTs including Thrower-Stone-Wales and vacancy defects has been studied using non-equilibrium molecular dynamics simulation and the density functional theory calculations. The continuous SWCNT as a long nanofiber has been considered to construct the nanocomposite representative volume element. In this respect, an in-situ curing process was performed using the LAMMPS software and an in-house code. The results indicated that despite the enhancement of longitudinal and transverse Young's moduli, the shear moduli of the nanocomposite with the pristine SWCNT were reduced compared to the pure polymer. It was shown that although the presence of defects reduces the elastic properties of isolated SWCNTs, they improve the nanocomposite properties. To explain these findings, the influence of defects on the structural integrity of nanocomposite and interfacial bonding strength has been investigated.