Determination of the interfacial properties of carbon nanotube reinforced polymer composites using atomistic-based continuum model

The present study investigates the interfacial properties of carbon nanotube (CNT) reinforced polymer composites by simulating a nanotube pull-out experiment. An atomistic description of the problem is achieved by implementing constitutive relations that are derived solely from interatomic potentials. Specifically, we adopt the Lennard-Jones (LJ) interatomic potential to simulate a non-bonded interface, where only the van der Waals (vdW) interactions between the CNT and surrounding polymer matrix are assumed to exist. The effects of such parameters as the CNT embedded length, the number of vdW interactions, the thickness of the interface, the CNT diameter and the cut-off distance of the LJ potential on the interfacial shear strength (ISS) are investigated and discussed. The problem is formulated for both a generic thermoset polymer and a specific two-component epoxy based on a diglycidyl ether of bisphenol A (DGEBA) and triethylene tetramine (TETA) formulation. The study further illustrates that by accounting for different CNT capping scenarios and polymer morphologies around the embedded end of the CNT, the qualitative correlation between simulation and experimental pull-out profiles can be improved.