Preparation And Tribological Properties Of Graphene Oxide-Microcapsule/Polymer Composites

In this paper, modified graphene oxide (MGO) was obtained by using the γ-methyl-propylene (KH-570) to modify the graphene oxide (GO). Microcapsules with compound bilayer capsule wall of graphene oxide (MGO-MicroLMs) through the seeded micro-suspension polymerization using the composite system of MGO and styrene monomer as wall material, n-Butyl stearate as core material. The MGO-MicroLMs was doped with styrene (St) and epoxy resin (E-51) respectively, the MGO-MicroLMs/PS composites and MGO-MicroLMs/EP were prepared according to the bulk casting method adopting MGO-MicroLMs as lubricating additive.The chemical composition, microstructure, thermal stability and mechanical properties of MGO-MicroLMs was characterized by Fourier transform infrared spectroscopy (FT-IR), X ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), contact angle tester, particle size analyzer, differential scanning calorimeter (DSC), thermogravimetric analyzer (TG) and ultraviolet visible spectrophotometry meter. The thermal stability of the composites was tested by TG tester, fracture behavior properties of the composites was evaluated by microcomputer controlled electronic universal testing machine. Tribological properties were evaluated by high speed reciprocating friction and wear tester. The surface topography of wear scar was observed by Mico-XAM non-contact 3D surface profiler, and the wear rate was calculated. The micro morphology of the surface of the composite grinding trace was observed by SEM, and the wear mechanism was analyzed.The results showed that MGO-Microcapsules were a spherical structure with uniform distribution. With the increase of MGO content, The average particle diameter of the microcapsules was reduced, the sealing property of microcapsules increased, permeability decreased 32.17% when the content of MGO was 0.6wt%, the hardness increases from 5.83MPa to 11.79MPa, and the thermal stability and hydrophilicity was also obviously improved. MGO-MicroLMs was uniformly dispersed in polystyrene and epoxy resin matrix materials. MGO-MicroLMs had a significant toughening effect for polystyrene and epoxy resin matrix material. In the process of friction, complexed lubrication film was formed by synergistic action with GO and butyl stearate, it led to a smaller friction coefficient and lower the wear rate, with lubrication and friction-reducing effect, the main wear mechanism was abrasive wear. When the content of MGO-MicroLMs was 20 wt%, friction coefficient of the MGO-MicroLMs/PS composite and MGO-MicroLMs/EP composite was respectively 0.157 and 0.13844, wear volume reduced respectively about 17.4% and 42.3%.