Molecular Dynamic Simulation of Carbon Nanotube Reinforced Nanocomposites: The Effect of Interface Interaction on Mechanical Properties

The mechanical properties of single wall carbon nanotube reinforced polymer (CP) composite have been investigated using COGNAC in molecular dynamic (MD) simulations. Nanocomposites are constructed by embedding single wall CNT (5,5) into acrylate based polymer under the periodic boundary condition with different interface interaction. Nanocomposites systems underwent NPT (constant number of atoms, pressure and temperature) and NVT (constant number of atoms, volume and temperature) ensemble with applied uniform strain during the MD simulations. The effect of the quality of filler-matrix interface on the mechanical properties was evaluated by altering the van der Waals interaction energy potential between the polymer and the filers. It is demonstrated that in spite of the presence of different interface interaction, Young's modulus of the pure polymer is enhanced by incorporating CNT and leads to mechanical properties exceeding the unfilled polymer. The tensile strength and the ultimate stress also follow similar tendencies. The results demonstrate that, there may be a reasonable relationship between the interfacial bonding and the load transfer between the matrix and fillers which has great impact on the mechanical properties of the nanocomposites. It was shown that by increasing the interface interaction, the opposite effects are observed in Young's modulus, tensile strength and the ultimate stress point. The observation confirms that the incompressibility of the interface region under the optimum interface interaction leads to the optimum mechanical properties.