Defect structure evolution of polyacrylonitrile and single wall carbon nanotube nanocomposites: a molecular dynamics simulation approach

So Jeong Heo,Byungchan Han,Seung Geol Lee,Han Gi Chae,Kwang Ho Kim

doi:10.1038/s41598-020-68812-7

Abstract

In this study, molecular dynamics simulations were performed to understand the defect structure development of polyacrylonitrile-single wall carbon nanotube (PAN-SWNT) nanocomposites. Three different models (control PAN, PAN-SWNT(5,5), and PAN-SWNT(10,10)) with a SWNT concentration of 5 wt% for the nanocomposites were tested to study under large extensional deformation to the strain of 100% to study the corresponding mechanical properties. Upon deformation, the higher stress was observed in both nanocomposite systems as compared to the control PAN, indicating effective reinforcement. The higher Young’s (4.76 ± 0.24 GPa) and bulk (4.19 ± 0.25 GPa) moduli were observed when the smaller-diameter SWNT(5,5) was used, suggesting that SWNT(5,5) resists stress better. The void structure formation was clearly observed in PAN-SWNT(10,10), while the nanocomposite with smaller diameter SWNT(5,5) did not show the development of such a defect structure. In addition, the voids at the end of SWNT(10,10) became larger in the drawing direction with increasing deformation.

Highlights

In this study, molecular dynamics simulations were performed to understand the defect structure development of polyacrylonitrile-single wall carbon nanotube (PAN-single-wall carbon nanotubes (SWNTs)) nanocomposites
Void structure formation may adversely affect on the resulting properties of nanocomposites, no significant deterioration of mechanical properties has been observed, which may be due to the ductile nature of polymer matrix and/or because the strong interaction between polymer matrix and Carbon nanotube (CNT) may overcome the effect of the void
Jain et al.[19] showed the elongated void structure at the end of PAN/vapor grown carbon nanofiber (VGCNF) nanocomposites where the VGCNFs diameter is on the order of hundred nanometers

Summary

Introduction

Molecular dynamics simulations were performed to understand the defect structure development of polyacrylonitrile-single wall carbon nanotube (PAN-SWNT) nanocomposites. A computer simulation study based on molecular dynamics (MD) was conducted to clearly show the effect of CNT on the void structure formation under large deformation, which mimics the drawing process in fiber manufacturing.

Results

Conclusion