目的 提高石墨烯在有机涂层中的分散性，并赋予其一定的功能性，制备一种方法简单、环境友好、成本低廉的水性环氧复合涂层。方法 以氧化石墨烯为原料，以1-(3-二甲胺基丙基)-3-乙基碳二亚胺（EDC）为缩合剂，在常温下经酰胺化反应将天然缓蚀剂色氨酸接枝到氧化石墨烯表面。再利用水合肼将其部分还原，得到色氨酸功能化的石墨烯，并成功分散至水性环氧涂层中，制备出色氨酸功能化石墨烯/环氧复合涂层。选用红外光谱仪、拉曼光谱仪、扫描电镜及透射电镜对功能化石墨烯的片层结构和微观形貌进行分析；利用电化学工作站对复合涂层在3.5%NaCl溶液中的耐蚀行为进行评价。结果 色氨酸分子成功接枝在氧化石墨烯表面，且功能化的石墨烯在无水乙醇及水性树脂中表现出优异的分散性。在防护性能方面，较之于空白样及未改性石墨烯/环氧复合涂层，在浸泡40 d后，功能化石墨烯基复合涂层表现出最高的阻抗模值（107 Ω?cm2）及电荷转移电阻值。同时，在所有涂层中，经功能化石墨烯复合涂层覆盖后，金属基底表现出最为轻微的腐蚀。结论 功能性的石墨烯添加至水性环氧涂层中可以显著提高涂层的耐腐蚀性能。

The work aims to improve the dispersibility of graphene in the organic coating and give it a certain functionality to prepare a water-based epoxy composite coating with simple method, environmental friendliness and low cost. Graphene oxide was selected as raw material and EDC was chosen as condensing agent. At ambient temperature, a natural corrosion inhibitor was grafted on the surface of graphene oxide through amidation reaction. Tryptophan functionalized graphene was prepared by hydrazine reduction and then successfully dispersed into waterborne epoxy resin to obtain the tryptophan functionalized gra-phene/epoxy coating. FTIR, Raman, SEM and TEM were employed to analyze the laminate structure and morphology of func-tionalized graphene. The corrosion resistance of as-prepared coating in 3.5%NaCl solution was evaluated by electrochemical workstation. Tryptophan was successfully grafted onto the surface of graphene oxide, and the functionalized graphene exhibited excellent dispersibility in absolute ethanol and waterborne epoxy resin. In terms of protective performance, the functionalized graphene-based composite coating displayed the highest impedance modulus (107 Ω?cm2) and charge transfer resistance after 40 days of immersion compared to the blank and unmodified graphene-based composite coating. Meanwhile, the surface of metal substrate exhibited the slightest corrosion among all coatings after being covered by the functionalized graphene composite coating. Thus, the addition of functional graphene can significantly improve the corrosion resistance of waterborne epoxy coating.