Molecular Dynamics Simulation of the Fracture in Polymer‐Exfoliated Layered Silicate Nanocomposites

Abstract

Summary: The MD technique was used to investigate the fracture behavior in fully exfoliated layered silicate (nanoplatelet)‐polymer nanocomposites. MD results reveal that the addition of the nanoplatelets can improve the fracture strength of polymers. The interactions between the surface of the nanoplatelets and the segments of the polymer, and the relaxation time of polymer chains have significant influences on the fracture strength of the polymer. For polymers with Tg below room temperature, such as polyurethane, or close to room temperature, such as nylon, the nanoplatelets are always working for the enhancement of the mechanical properties. However, for polymers with Tg above room temperature, such as epoxy and polystyrene, the addition of the nanoplatelets is not working well for toughening these polymers. If the nanoplatelets are to enhance the mechanical properties of these polymers, it is necessary to build up a stress relaxation interface between the polymer and the nanoplatelet in order to reduce the effect of the difference between the relaxation time of nanofillers and that of polymers.Force per area versus distance curves as a function of the difference of the relaxation times of the nanoplatelets and polymer chains.magnified imageForce per area versus distance curves as a function of the difference of the relaxation times of the nanoplatelets and polymer chains.

Simulations of tensile bond rupture in single alkane molecules using reactive interatomic potentials

“…However, many researchers have used MD simulations with non-reactive potentials to investigate fracture related phenomena or to calculate fracture properties. [15][16][17][18][19][20][21][22] For example, Song and Chen 17 used a beadspring model for a polymer with a Lennard-Jones type potential 23 to investigate the fracture behavior in a polymer-exfoliated layered silicate nanocomposite. They concluded that interactions between the surface of the nanoplatelets and segments of the polymer chains, as well M a n u s c r i p t 5 as the relaxation time of polymer chains, significantly influence the fracture strength of the polymer.…”

Atomistic analyses of the effect of temperature and morphology on mechanical strength of Si–C–N and Si–C–O nanocomposites

“…Classical MD based atomistic analyses of the nanocomposite mechanical deformation as a function of phase morphology are relatively new and have focused on a very limited sets of issues in metallic, polymer-clay, and ceramic nanocomposites. [17][18][19][20][21] Both SiC and Si 3 N 4 have been individually analyzed in the atomistic simulations for different mechanical strength related issues. [22][23][24][25] However, SiC-Si 3 N 4 nanocomposite morphologies are analyzed in this work for the first time for understanding temperature dependent strength.…”

An Analysis on Enhancement of Fatigue Durability of Polyurethane by Incorporating Organoclay Nanofillers

“…Models and simulation parameters can be found in ref. [28] Figure 11 shows the simulated stress-strain curves for deformations up to 100% for loading and unloading cycles 1-4. Obviously, the dissipated energy in the first cycle is greater than that in the following cycles, and the dissipated energies were almost the same at second, third and fourth cycles represented by the equal areas as shown in Figure 11.…”