Characterizations of Mechanical Interfacial Tribological and Thermal Properties of Graphene TPU Nanocomposites Using MD OOF2 Simulations and Experiments for Different Concentrations of Graphene in Various Forms

Abstract

Nanocomposites are composite materials in which the matrix material is reinforced by one or more nanomaterials having dimensions in the nanometre range. The small size of nano reinforcements at low concentrations increases interfacial surface area to change the mechanical, tribological and thermal properties of nanocomposites significantly. Out of all reinforcing materials, graphene (Gr) is considered to be the most important one, consisting of carbon atoms, in a hexagonal pattern with the shortest distance of 1.42 Å between atoms with a bond angle of 120° and thickness of 0.335 nm. This work is primarily based on Molecular Dynamics (MD) simulation but the 2-dimensional OOFEM simulation (i.e. OOF2) has also been done for comparison of properties with those from experimental results. newlineBoth the simulations showed increase in Young s modulus of pure Gr/TPU up to 3 wt. % Gr addition, beyond which it decreases.The effects of different forms of Gr, i.e. its shape, defect, functionalized form (fGr), defective functionalized form on the interfacial mechanical properties of Gr/TPU nanocomposites have been assessed by MD simulations. Results showed that interfacial thickness between TPU and Gr play a major role in the improvement of interfacial mechanical properties. newlineFrom the MD simulation based tribological study it is observed that there is a decrease in coefficient of friction (COF) of TPU from 0.51 to 0.42 and for abrasion rate (AR) from 35 % to 19 % due to addition of 3 wt. % fGr in pure TPU under confined shear velocity of 11 m/s. newlineDifferent experiments for Gr/TPU nanocomposites such as the microstructural study, tensile testing, Dynamic Mechanical Analysis (DMA) testing, abrasion testing and coefficient of friction testing are done in this work. Improvement in the Young s modulus of pure Gr/TPU is the maximum at 3 wt. % Gr. Young s modulus of 3 wt. % Gr/TPU is 1.31 GPa as obtained from MD simulation, 0.40 GPa from OOF2 simulation and 0.050 GPa from tensile testing. Trends of the results are similar in all the three