石墨烯掺杂环氧复合涂层的制备及防腐性能的研究

Preparation of graphene-doped epoxy composite coatings and their anti-corrosion properties

通过简单的化学反应,将3-氨丙基三乙氧基硅烷和3-缩水甘油醚氧丙基三甲氧基硅烷接枝在氧化石墨烯上,制备成复合材料(GO-APTES与GO-GPTES)。2种表面改性剂使氧化石墨烯更易于与环氧-胺树脂产生化学键。通过微观电镜以及可见-近红外全波段透过率测试实验,发现改性剂作用后的氧化石墨烯能均匀分散在树脂体系中。相比较于纯的环氧-胺树脂涂层,GO-APTES/Resin涂层的蒸汽透过率降低30%,形成“迷宫效应”,对水蒸气具有良好的阻隔效果。通过Bode和Nyquist图谱研究了复合涂层的防腐机理。添加改性氧化石墨烯后的涂层对腐蚀介质的屏蔽性增强,腐蚀介质穿透涂层的能力降低,因此在涂层与金属的界面处改性氧化石墨烯分散的树脂涂层能够更好的附着,电化学腐蚀的面积更小,表现出更优秀的腐蚀防护性。中性盐雾实验表明,经过7000 h,涂层表面无起泡,无脱落。

Through simple chemical reactions,3-aminopropyl triethoxysilane and 3-glycidyl ether oxypropyl trimethoxysilane have been successfully grafted onto graphene oxide to prepare composite of a sandwich structure.The two surface modifiers make it easier for the graphene oxide to form chemical bonds with epoxy resin/polyamine.Through electron microscope and visibleinfrared full-band transmittance tests it is found that the graphene oxide treated by the modifier can evenly disperse in the resin system.Compared with the pure epoxy amine resin coating,the water vapor transmittance of the GO-APTES/Resin coating is reduced by 30%.A"labyrinth effect"is formed,which is a good barrier against water vapor.Moreover,the anti-corrosion mechanism of the composite coating is studied by Bode and Nyquist spectra.The shielding of the coating against the corrosive medium is enhanced after adding modified graphene oxide,and the ability of the corrosive medium to penetrate the coating is reduced.Therefore,the coating is better attached to the metal and the area of electrochemical corrosion is smaller,having a better corrosion protection ability.Neutral salt spray test shows that the coating surface will not fall off or present blister after 7000 hours.