Molecular dynamics of single-wall carbon nanotube wrapped with polypropylene

Abstract

Nowadays, the nanocomposite materials have been widely used in various applications due to their unique properties such as thermal and electrical properties. Polymer/carbon nanotube (CNT) nanocomposite is one the important nanocomposite materials that are manufactured for improving thermal conductivity and electrical properties of polymers. Unfortunately, polypropylene (PP)/CNT preparation is difficult because of CNT dispersion and aggregation. Accordingly, amylose (AMY) and chitosan (CS) are selected in the present study in order to demonstrate how AMY and CS could diminish such problems by non-covalent modification on outer surface of single-walled CNT using molecular dynamics (MD) simulations. The MD results reveal that AMY wrapped on CNT could induce the binding efficacy of PPs (atactic polypropylene (aPP), isotactic polypropylene (iPP) and syndiotactic polypropylene (sPP)) toward CNT by a significant reduction of distance between the center residue located on each amylose spiral and the adjacent one, especially for iPP and sPP systems. The radius of gyration shows that PPs spirally wrapped around CNT. Additionally, electrostatic attraction is found to be the main interaction inducing PPs to become spirally contacted with CNT. In case of CS modification, it can induce PPs binding but not in a spiral-shape on CS outer surface. The radius of gyration of PPs in CS modified CNT system conflicts with that of AMY model due to it interact with CNT/CS in snake-like shape of electrostatic interaction.