| Presently,epoxy coating is the most widely used coating system for protection of metal.There are two typical interfaces in epoxy coating:metal/coating interface and filler/coating interface,in which the adhesion based on physical adsorption is poor and affects the improvement of performances of epoxy coating.To this end,the concept of interfacial chemical bonding is introduced in this paper.By using organic synthesis,molecules with chemical bonding activity are produced and incorporated into the coating to change the adhesion forms from physical adsorption to chemical bonding.Thus,the anti-corrosion performance of epoxy coatings are expected to be significantly improved.Based on this concept,the research work of this thesis divided into two parts:1.Chemical bonding of metal/coating interface.First,an active resin called ?-APS/EP were synthesized by using 3-Aminopropyltrimethoxysilane and epoxy resin E51,and then were added into epoxy coating to chemically bond the metal interface.By employing organic coating performance tests,such as adhesion strength tests,water absorption tests and electrochemical impedance spectroscopy(EIS),and structure analysis methods,such as X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDXS),influences of the contents of active resin on the properties of the coating were studied.Besides,the chemical bonding mechanism in the metal/coating interface was preliminarily studied.Following are the main conclusions:Coating adhesion was notably enhanced and reached the highest strength with an addition of 3wt%y-APS/EP;meanwhile,the anti-permeability and anti-corrosion performance of the coating were also significantly improved.The content of ?-APS/EP affects the degree of hydrolysis and polymerization of the alkoxy group on ?-APS/EP,which affected both the number of chemical bonds at the metal/coating interface and the denseness of the coating,and ultimately determined the corrosion resistance of the coating.2.Chemical bonding of filler/coating interface.Graphene oxide was used as the filler,and it was covalently modified with triethylenetetramine before incorporated into coating to synthesize a filler with chemical bonding activity.Fourier transform infrared spectroscopy,X-ray diffraction and Raman spectroscopy(Raman)were employed to analyze the structure variation of GO.Coating performances were tested by Laser confocal microscopy,adhesion tests,and electrochemical impedance spectroscopy.The main findings are as follows:Compatibility of graphene oxide was much improved by chemical modification,which was mainly reflected both by the decrease of the deposition rate of graphene oxide in organic solvents and the decrease of the size of the lamellar of graphene oxide in the coating.Moreover,covalently modified graphene oxide distributed more homogeneously in the coating,which not only improved the adhesion of coating,but also denser the coating.Thus,the anti-corrosion performance was improved. |
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