Microstructure And Properties Of Epoxy Resin Coatings Modified By Different Types Of Graphene

Epoxy coating has the advantages of chemical stability,electrical insulation,corrosion resistance,etc.However,due to the volatilization of the solvent in the curing process,the internal defects such as pores and micro-cracks will be formed,which seriously limits its application in harsh environments.Graphene is considered as an ideal nano-filler due to its large specific surface area,small volume,toughness,and self-lubricating performance.Therefore,graphene has great potential as a modification material for epoxy resin coatings.In this paper,Fourier Transform Infrared Spectroscopy(FTIR),X-ray Photoelectron Spectroscopy(XPS)and Transmission Electron Microscopy(TEM)were used to characterize the chemical bonds,functional groups,morphology of RGO,to select the best graphene for the exploration test.Graphene modified epoxy resin composite coatings were prepared by adding graphene(RGO)with different reduction degrees and specific surface areas into the epoxy resin coatings.The effect of reduction degree and specific surface area of RGO on the corrosion resistance of epoxy resin was studied,and the corrosion resistance mechanism was explored.The experimental results show that the corrosion resistance of the composite coating is gradually improved with the increase of graphene reduction degree.The charge transfer resistance of the r GO/epoxy composite coating with a reduction degree of 97.86 at.%is4.911×10~5?,which is about 9 times higher than that of the pure epoxy coating.The specific surface area of graphene has a significant effect on the corrosion resistance of epoxy resin.The charge transfer resistance of the r GO/epoxy resin composite coating with a specific surface area of 725.8 m~2/g is 1.793×10~7?,which is 3 orders of magnitude higher than that of the pure epoxy resin coating,showing excellent corrosion resistance.The influence of temperature on the thermal and impermeable properties of RGO modified epoxy resin composite coating and its corrosion resistance in high salinity drilling environment were studied by electrochemical workstation,Field Emission Scanning Electron Microscopy(FESEM),water vapor permeation test system and magnetic force driven autoclave.The experimental results show that the corrosion resistance of the composite coating gradually decreases with the increase of temperature.The charge transfer resistance of the composite coating at low temperature increases by 3 orders of magnitude compared with that of the pure epoxy resin coating,and the charge transfer resistance of the composite coating at high temperature is approximately 10 times of the pure epoxy resin coating.Dropping impact test,sand drop test and tensile test were used to study the effect of the reduction degree of graphene on the mechanical properties of epoxy coating.The experimental results show that,compared with the pure epoxy resin coating,the impact property of the composite coating modified by RGO with a reduction degree of 97.86at.%is increased by about 300%,the wear coefficient is decreased by 85.2%,and the tensile strength is increased by 5.03MPa.