Tribo-mechanical properties of pure thermoplastic polyurethane and functionalized monolayer graphene-reinforced thermoplastic polyurethane polymer nanocomposites are investigated by molecular dynamics simulations. Initially, the mechanical properties of the thermoplastic polyurethane and functionalized monolayer graphene-reinforced thermoplastic polyurethane nanocomposites are measured by applying constant stain method. Subsequently, interfacial layer models are developed to apply confined shear on the iron layers to find out the coefficient of friction and the abrasion rate of pure thermoplastic polyurethane and functionalized monolayer graphene-reinforced thermoplastic polyurethane nanocomposites. The results imply that by the incorporation of 0.5 wt.% functionalized monolayer, graphene shows the increase of 20% in Young’s modulus, 15% in shear modulus and 6.66% in bulk modulus of pure thermoplastic polyurethane, respectively, which are in good agreement with the previous experimental studies. Maximum enhancement of mechanical properties can be obtained up to 3 wt.% addition of functionalized monolayer graphene addition in thermoplastic polyurethane matrix. Further, it is observed that 3 wt.% of functionalized monolayer graphene-reinforced thermoplastic polyurethane nanocomposite results in minimum coefficient of friction (0.42) and abrasion rate (19%) under constant normal load (5 kcal/mol/Å) and maximum sliding velocity (11 m/s). However, further reduction in minimum values of coefficient of friction and abrasion rate at 3 wt.% of functionalized monolayer graphene-reinforced thermoplastic polyurethane nanocomposites is seen under the minimum sliding velocity (1 m/s) considered with the same normal load condition. Finally, the inherent mechanisms for enhancement of tribo-mechanical properties in functionalized monolayer graphene-reinforced thermoplastic polyurethane nanocomposites are analysed by the atomic density profile, free volume and Connolly surface at the atomic level.

No abstract

Multiscale modelling and simulations, based on molecular dynamics (MD) and object-oriented finite element method (OOFEM), are two important simulation tools to predict property enhancement of polymer nanocomposites for designing armor-type components in requisite applications. In this study, MD simulation software (Materials Studio) is used to develop 0.5%, 1%, 2%, 3%, and 4% (by weight) single-layer graphene (SLGR)-reinforced thermoplastic polyurethane (TPU) nanocomposites to find out their mechanical properties (mainly elastic moduli and Poisson’s ratio) using constant strain method. OOFEM simulation software (OOF2) is used for mechanical characterization of 0.5%, 3%, and 4% (by weight) SLGR-reinforced TPU nanocomposites from scanning electron microscopy–generated microstructures. Properties obtained from both the simulations are compared with experimental results to know the nanoreinforcement effect in atomic level as well as in microlevel in the nanocomposites. It is observed that the results based on OOF2 simulation are closer to the experimental results compared with the results obtained from MD simulation in this multiscale modelling and simulation study.

No abstract

No abstract