Abstract:
Since their discovery in 1991, carbon nanotubes (CNTs) have been the focus of
considerable research due to their remarkable physical and mechanical properties
reported. This form of carbon has potential applications in numerous conventional and
new areas - light-weight structural materials being just one of them. The strength to
weight ratio of CNTs is higher than any currently known material; hence their use to
reinforce polymers has been of great interest. Due to the highly expensive testing
equipment and limited scope of experimental techniques, atomistic and continuum
simulations are being used for characterization of CNTs and CNT based nanomaterials.
This research concentrates on molecular dynamics simulations (MDS) of amorphous
polyethylene and CNT- polyethylene composites. The composite being investigated
consist of amorphous polyethylene with embedded single-walled CNT. The CNT is
modeled by the Brenner potential while united-atom approach is used for modeling
the polymer chains CH2 (methylene) group as a single united atom in the polymer
system. The van der Waals interaction between the nanotube and polymer is modeled
using Lennard-Jones potential. All the systems were subjected to quasi-static tensile
loading. For simplicity, no cross-link chemical bond between the CNT and
polyethylene matrix in the nanocomposites is considered.
Here, mechanical properties of amorphous polymer and its CNT reinforced
composites have been investigated using MDS. The effects of polymer density,
polymer chain length and temperature on the mechanical properties of polymer have
been studied. In case of composite the effects of CNTs volume fraction on the
mechanical properties of CNT-Polyethylene composite have been checked and
compared with the existing theoretical formula. The load transfer scenario through the
interfacial region has also been investigated here and compared with the existing
theoretical Cox’s model.
