Investigation Of Tribological Properties Of Graphene/UHMWPE Composite Materials

In all areas of modern industrial development are inseparable from the friction. There areabout1/3to1/2of energy waste in friction.If we can reduce unnecessary friction consumption,we can save a lot of energy, reduce equipment maintenance times and costs, but also save thecost of manufacturing parts and materials needed. Vigorously develop less wear resistantmaterial is an important part of the development of green tribology.Ultra-high molecularweight polyethylene (UHMWPE) has superior mechanical and mechanical properties.But itslow surface hardness and flexural strength, poor creep resistance defects, hindering the furtherapplication of ultra-high molecular weight polyethylene.In this paper graphene oxide (GO) is prepared by the improved method of Hummer, andthen GO and UHMWPE powder are blended in absolute ethanol with ultrasonic agitationthrough the solution blending method. The obtained mixed powder was molded in a hot pressmold container made to prepare a GO/UHMWPE composite. After that, the feature andthickness are analysed by scanning electron microscopy and atomic force microscopy. Thestructure of prepared sample are analysed by X-ray diffraction, Raman spectroscopy. Fouriertransform infrared spectroscopy. Overall results show that GO is a film-like sheet structure,single GO thickness of about1-2nm. GO surface exist carboxyl group, carbonyl group,hydroxyl group and epoxy group. These groups cause wrinkles phenomenon. The sheet size ismicron level, with4-5layers overlap, does not appear agglomeration. GO have a good degreeof oxidation. Due to the presence of these oxygen-containing groups leads to the originalgraphite crystal structure changes, the sp2hybrid surface become to narrow and change to thesp3hybrid surface. Lattice defect is increased, the interlayer distance becomes large andswollen.In the study of the mechanical properties. Hardness of GO/UHMWPE compositematerials are significantly improved. When the mass fraction of0.1wt%, the hardness ofGO/UHMWPE composite material is69.2HRM, higher than the hardness of pure UHMWPE,the hardness enhance11.43%. In experiments testing the tensile properties. When the lowmass fraction GO, the yield strength and tensile strength of GO/UHMWPE composite hasimproved compared to the pure UHMWPE. With the GO content rises, the yield strength andtensile strength decline. In the study of the tribological properties, under dry conditionsfriction coefficient of GO/UHMWPE composite increased slightly compared with pureUHMWPE. The composite friction coefficient have no significant relationship with GO fillingamount. GO fillers improve the wear resistance of UHMWPE, when GO mass fraction of1%,the largest decline in wear rate was38.5%. Under water lubrication conditions, the friction coefficient of pure UHMWPE and composite material range from0.6to0.85. The pureUHMWPE and composite materials have better wear resistance. The composite shows thebest wear resistance when the GO mass fraction is0.1wt%. The maximum wear loss is3.65mg, reduced33.55%comparing with dry friction condition. In addition, both the frictioncoefficient and wear amount increases with the load. With the increase in filling amount ofGO, the impact of load on the friction coefficient and wear amount is increasing to thecomposite material. The results show that GO/UHMWPE composites compared with pureUHMWPE has superior mechanical and tribological properties. It also has a good applicationvalue in the development of less wear resistant material respects.