Estimation of improvement in elastic moduli for functionalised defective graphene-based thermoplastic polyurethane nanocomposites: a molecular dynamics approach

Abstract

ABSTRACT This molecular dynamics (MD) simulation-based study provides a comprehensive investigation about improvement in elastic moduli and strength properties of Stone–Wales defective hydrogen functionalised graphene-reinforced thermoplastic polyurethane (SW-fGr/TPU) nanocomposite. Three models, namely concentration model (CM), stacked model (SM) and interfacial model (IM), have been used here to estimate improvements under the effect of weight concentrations, aspect ratios, dispersion and stacking conditions using the constant strain method with COMPASS II force field. High enhancement in moduli values is observed for CM models due to the high aspect ratio and 4 wt-% of SW-fGr addition in pure TPU. The values of in-plane elastic moduli of stacked dispersed models are found to be higher than the values of stacked agglomerated models. Out of all SM models, maximum in-plane and out-of-plane shear moduli are obtained in the agglomerated (stacked) Gr conditions. The interfacial normal strength is found to be substantially higher than interfacial shear strength within the IM models. The enhancement of elastic moduli in SW-fGr/TPU has been confirmed by using atomic density profile, fractional free-volume calculation and Connolly surface analyses. Some of these MD simulation results are in good agreement with those from previous investigations.