This study reports a strategy for further simplifying the synthesis process of polyaniline-modified graphene (An/G) nanocomposite. For this purpose, the An/G nanocomposite was prepared by expanded graphite (EG) and aniline (An) via in situ polymerization. The structures and morphologies of the An/G nanocomposite were examined by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, ultraviolet–visible spectroscopy and atomic force microscopy. The results show that the An/G nanocomposite was synthesized successfully. The coatings were prepared using polyaniline (PANI) and An/G as the fillers and epoxy resin as the matrix. The anti-corrosion performance was evaluated by electrochemical impedance spectroscopy, Tafel polarization curve and salt immersion test. When An/G100 nanocomposite with a mass ratio of An to EG of 100:1 as a filler is used, the coating on the steel exhibited superior anti-corrosion effect. In particular, the impedance at 0.01 Hz of the coating with the An/G100 nanocomposite at a low loading of 2 wt% (An/G100-2) remained constant above 1 × 1010 Ω·cm2 for up to 35 days in 3.5 wt% sodium chloride solution. The Tafel plots reveal that the undamaged zone of the An/G100-2 coating possessed a high corrosion potential of −0.16 V, and the corrosion current density was only 1.5 × 10−11 A cm−2. The protective mechanism of graphene and PANI is discussed.

中文翻译：

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原位插层聚合制备石墨烯/聚苯胺纳米复合材料及其在防腐涂料中的应用

本研究报告了一种进一步简化聚苯胺改性石墨烯 (An/G) 纳米复合材料合成过程的策略。为此，通过原位聚合通过膨胀石墨 (EG) 和苯胺 (An) 制备 An/G 纳米复合材料。通过傅里叶变换红外光谱、X 射线衍射、扫描电子显微镜、透射电子显微镜、拉曼光谱、紫外-可见光谱和原子力显微镜检查 An/G 纳米复合材料的结构和形貌。结果表明成功合成了An/G纳米复合材料。以聚苯胺（PANI）和An/G为填料，环氧树脂为基体制备涂层。通过电化学阻抗谱、Tafel极化曲线和盐浸试验对防腐性能进行评价。当使用An/EG质量比为100:1的An/G100纳米复合材料作为填料时，钢上的涂层表现出优异的防腐效果。特别是，在 2 wt% (An/G100-2) 的低负载下，具有 An/G100 纳米复合材料的涂层在 0.01 Hz 下的阻抗在 1 × 1010 Ω·cm2 以上保持恒定，在 3.5 wt% 下长达 35 天氯化钠溶液。Tafel 图显示 An/G100-2 涂层的未损坏区域具有 -0.16 V 的高腐蚀电位，腐蚀电流密度仅为 1.5 × 10-11 A cm-2。讨论了石墨烯和PANI的保护机制。具有 2 wt% (An/G100-2) 低负载量的 An/G100 纳米复合材料的涂层的 01 Hz 在 1 × 1010 Ω·cm2 以上保持恒定在 3.5 wt% 氯化钠溶液中长达 35 天。Tafel 图显示 An/G100-2 涂层的未损坏区域具有 -0.16 V 的高腐蚀电位，腐蚀电流密度仅为 1.5 × 10-11 A cm-2。讨论了石墨烯和PANI的保护机制。具有 2 wt% (An/G100-2) 低负载量的 An/G100 纳米复合材料的涂层的 01 Hz 在 1 × 1010 Ω·cm2 以上保持恒定在 3.5 wt% 氯化钠溶液中长达 35 天。Tafel 图显示 An/G100-2 涂层的未损坏区域具有 -0.16 V 的高腐蚀电位，腐蚀电流密度仅为 1.5 × 10-11 A cm-2。讨论了石墨烯和PANI的保护机制。