Investigation of Graphene Reinforcement Effect on Young's Modulus of Cross-Linked Epoxy Nanocomposites by a New Heuristic Protocol

Abstract

The effect of graphene reinforcement on Young's modulus of cross-linked epoxy was examined using a new heuristic method. The heuristic protocol is less sophisticated than the multi-step iterative approach. It also updates higher-order covalent bonds and partial charge terms in real-time to prevent inaccurate chemical couplings caused by ignoring angle-based covalent terms. Graphene reinforcement was investigated for 1%, 2%, 3%, and 4% weight ratios. The edges of graphene sheets were functionalized with hydrogen atoms and placed non-periodically in simulation cells. Each simulation cell was built as three samples to analyze the multiple variations with the same number of molecules in each weight ratio, and the standard deviation values were calculated. Young's modulus of the nanocomposite system was calculated using a constant-strain energy minimization approach. Young's modulus of epoxy increased with graphene reinforcement, as expected. This increase was calculated by 6% for 1% graphene reinforcement, 10% for 2% graphene reinforcement, 14% for 3% for graphene reinforcement, and 16% for 4% for graphene reinforcement. As the graphene reinforcement ratio increased, the rise in Young's modulus tended to diminish. It is also worth noting that the MD simulation results in this work were in close agreement with the experimental results published in the literature.