间苯二胺-氧化石墨烯/有机涂层的制备及防腐性能研究

针对有机涂层中氧化石墨烯(GO)分散性差、与树脂相容性不好的问题,本工作选择间苯二胺作为"桥接物质",利用其分子上的两个胺基与GO和环氧树脂的环氧基团分别键合,从而改善GO与环氧树脂间的相容性。同时,利用间苯二胺的空间位阻效应有效改善了GO的团聚问题,提高在环氧树脂中的分散性。采用化学接枝法得到间苯二胺表面改性的GO(M-GO),并制备了M-GO与环氧树脂E-44复合涂料(EP/M-GO)。结果表明,间苯二胺的胺基能够成功与GO表面的环氧基团键合,且在透射电镜下可以观察到M-GO呈现出少量片层的状态,团聚现象明显改善。另一方面,涂层截面形貌表明M-GO与基料树脂之间结合良好。复合涂料在12 d的盐雾实验后仍然能够为金属基底提供保护,且浸泡1000 h后的阻抗模值(|Z|0.01 Hz)仍可达109数量级,防腐性能明显提高。

Preparation and Anticorrosion Performance of M-phenylenediamine-graphene Oxide/Organic Coating

In order to solve the problems of poor dispersion of graphene oxide(GO) in organic coatings and poor compatibility with resins, m-phenylenediamine, taking as the so called "bridge" material,was grafted on the surface of graphene oxide(GO) via a chemical means to obtain M-GO composite materials. Then the M-GO/epoxy resin E-44 composite anticorrosion coatings were also prepared. The results of FTIR, Raman and TGA showed that amine groups of m-phenylenediamine were successfully bonded with the epoxy group. A few layers of the M-GO composite particulates of lamellar morphology can be observed by transmission electron microscope(TEM), indicating that the dispersibility of GO was improved through m-phenylenediamine-grafting. On the other hand, the cross-sectional morphology of the coating showed that the M-GO composite material also has good compatibility with epoxy resin. In comparison with the epoxy resin coating GO/EP with the inherent graphene oxide GO, the M-GO/EP coating shows far more better anti-corrosion performance, namely, after 1000 h of immersion in 3.5%(mass fraction) NaCl solution, the impedance modulus(|Z |0.01 Hz) value of EP/M-GO stayed at 1.0×109Ω·cm2, and after salt spray test for 12 d, the M-GO/EP coating could still provide effective protection for the metal substrate. The results show that the m-phenylenediamine modified graphene oxide/organic coatings present significantly enhanced anti-corrosion performance.