Preparation Of Functionalized Graphene Composites And Study On The Corrosion Protection Of Its Coatings

The corrosion and protection of materials is a very important new discipline,and corrosion is the main cause of metal material failure.In recent years,the emergence of graphene has attracted attention on the various fields of academic circles.Studies have shown that graphene can form a physical barrier between the metal surface and the active medium,showing excellent resistance to permeability and corrosion.Graphene oxide(GO)with oxygen-containing organic functional groups on the surface,one of the derivatives of graphene,which can be modified and utilized.It can improve the dispersibility of GO in the matrix resin,thus graphene is better utilized in the field of graphene-based antic-orrosion coatingsIn this paper,modified GO and graphene have been synthesized through two non-covalent methods and they were added to the epoxy resin(EP)to prepare the anti-corrosion coatings.The basic properties and anti-corrosion performance of the coatings have been tested.The specific research contents are as follows:1.Firstly,the polyglycidyl methacrylate(PGMA)microspheres with uniform particle size were prepared by monodisperse polymerization.GO was adsorbed on the surface of the PGMA microspheres with the aid of the CTAB through a negative-positive electrostatic attraction,called PGMA@GO.The structures and morphologies of GO,PGMA and PGMA@GO was characterized by Fourier transform infrared(FT-IR)spectroscopy,X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Raman spectroscopy and dynamic laser light scattering(DLS),respectively.Then,the coatings with different addition amounts of GO,PGMA and PGMA@GO were prepared,called EP,PGMA/EP and PGMA@GO/EP coatings,respectively.The properties of these anti-corrosion coatings were also explored.The results show:PGMA@GO microspheres with a mass ratio of GO to PGMA of 2:1 have been successfully synthesized.The GO layers were wrapped on the surface of PGMA microspheres.The physical properties show that the adhesion and the hardness of the PGMA(@GO/EP coatings were improved slightly.The water contact angle test results show that the water contact angle of the PGMA@GO/EP coatings increased.The SEM images of the coatings reveal that the surface roughness of the PGMA@GO/EP coatings increased.The SEM images of fracture surfaces of the coatings indicate that the dispersion of GO was improved in the EP.The coatings with X-scribes show that the PGMA@GO/EP coatings still maintained the relatively good morphologies after being immersion in the 3.5%NaCl for 21 days.The Bode plots exhibit that the low frequency impedance(|Z|o.oi Hz)of the PGMA@GO/EP coatings were improved.Tafel polarization curves show that the corrosion current and corrosion rate of the PGMA@GO/EP coatings became smaller,which showed the best corrosion protection.2.The composite materials were prepared by non-covalent modification of graphene nanosheets(GNS).Firstly,the hydroxyazobenzene(AZO-OH)was synthesized by diazotization of aniline and phenol.Secondly,6-chloro-l-hexanol was subjected to chain extension reaction of AZO-OH to obtain monomer AZO-C1-OH.Thirdly,AZ-OH-C1 and methacryloyl chloride were acylated to obtain monomer AZO-MAC containing double bond.Finally,the random copolymer(AZO-GMA)was prepared via free radical polymerization using GMA and AZO-MAC.The synthesized monomers and polymer were characterized by FT-IR,1H-NMR and GPC.The AZO-GMA-GNS was synthesized by non-covalently AZO-GMA and GNS.The morphologies and structures of GNS and AZO-GMA-GNS were characterized by XRD,SEM,TEM and Raman.The coatings with different addition amounts of GNS and AZO-GMA-GNS were prepared,called GNS/EP and AZO-GMA-GNS/EP coatings.The properties of these anti-corrosion coatings were also explored.The result show:AZO-GMA-GNS has been successfully synthesized.The adhesion and hardness of the AZO-GMA-GNS/EP coatings were improved slightly.The water contact angle test results show that the water contact angle of the AZO-GMA-GNS/EP coatings increased.The SEM images of the coatings reveal that the surface roughness of the AZO-GMA-GNS/EP coatings increased.The SEM images of the fracture surfaces of the AZO-GMA-GNS/EP coatings indicate that the dispersion of GNS were improved in the EP,showing fish scale-like layered structure.The coatings with X-scribes show that the AZO-GMA-GNS/EP coatings still maintained the relatively good morphologies after being immersion in the 3.5%NaC1 for 21 days.The Bode plots exhibit that the |Z|0.01Hz values of the AZO-GMA-GNS/EP coatings were improved.Tafel polarization curves show that the corrosion current and corrosion rate of the AZO-GMA-GNS/EP coatings became smaller,which showed the best corrosion protection.