Mechanical and Viscoelastic Properties of In-situ Amine Functionalized Multiple Layer Grpahene /epoxy Nanocomposites

Abstract

Introduction: Graphene is flat monolayer of carbon atoms (one atom thick), covalently bonded to three other atoms in tightly packed two-dimensional (2D) hexagonal single layer stable crystalline honeycomb lattice structure. In this paper, In-situ amine functionalized exfoliated graphene with multiple layers (3-6) with low defect contents and average aspect ratio upto 10 microns (average X and Y dimensions) and thickness upto 2-3 nm (average Z-direction) which have been produced with the combined effort of chemical vapor deposition (CVD) and chemical graphite exfoliation method. Methods: This paper also focuses on the effect of the reinforcement of amine functionalized multiple graphene layers (AF-MGL) on the mechanical and visco-elastic properties of epoxy composites. AFMGL/ epoxy composites (AF-MGL/EpC) were prepared with graphene fractions ranging from 0.5 to 2.0 wt%. The four different samples were prepared using an amount of graphene as 0.0, 0.5, 1.5, and 2.0. A series of tensile three point bend tests were performed on the different AFMGL/epoxy composites. Optical and scanning electron microscopy (SEM) was used to examine the micro structural features and fractured surfaces of AF-MGL/EpC. Results: Increased graphene content results in improved tensile strength and the modulus of an epoxy matrix when compared with the pure epoxy matrix. The 1.5 wt% AF-MGL/EpC showed an increase in tensile strength and modulus by 50.2 and 52.8% respectively. However, a shrink was noticed beyond 1.5 wt.% samples of AF-MGL/EpC composite. Moreover, an improvement of 28.8% in the storage modulus was also recorded when compared with epoxy composites. Conclusion: The effect of the amine functional group on the mechanical and viscoelastic properties was also explored using molecular dynamics (MD) simulations and predicted results were then compared with experimental results.