Fabrication of excellent anti-corrosion epoxy coating based on GON-An composites

Polyaniline/graphene oxide (GON-An) composites were synthesized by chemically grafting p-phenylenediamine (PPDA)-modified graphene oxide (GO) with polyaniline (PANI), which was confirmed by FT-IR, XRD, SEM, TEM, Raman spectroscopy, and XPS analyses. The electrochemical impedance spectroscopy test, brine immersion, and Tafel slopes analysis revealed that compared with GO and PPDA-modified GO (GON), GON-An composites which combined the unique corrosion resistance of both PANI and GO exhibited relatively obvious superiority in improving the corrosion resistance of epoxy coating with the same contents. After being immersed in brine for 35 days, the composite epoxy coating containing 1 wt-% of GON-An(1:2) composites in which the mass ratio of GO and PANI was 1:2, possessed a high impedance of 4×109 Ω cm2, a high corrosion potential of −0.25 V, and a low corrosion current of 4.119×10−11 A cm−2. Furthermore, the anti-corrosive mechanisms of PANI/GO epoxy coatings were discussed.

聚苯胺（Polyaniline）/氧化石墨烯（graphene oxide）复合材料（GON-An）通过将对苯二胺（p-phenylenediamine，PPDA）改性氧化石墨烯（GO）与聚苯胺（PANI）进行化学接枝制备得到，该合成过程经傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、拉曼光谱（Raman spectroscopy）及X射线光电子能谱（X-ray Photoelectron Spectroscopy，XPS）表征验证。电化学阻抗谱测试、盐水浸泡试验与塔菲尔斜率分析结果表明，相较于纯GO与PPDA改性GO（GON），同时兼具聚苯胺与氧化石墨烯独特耐腐蚀性能的GON-An复合材料，在同等添加量下提升环氧涂层耐腐蚀性能方面优势显著。当环氧涂层中添加1 wt%的GON-An(1:2)复合材料（该复合材料中GO与PANI的质量比为1:2），经35天盐水浸泡后，该复合涂层仍具备4×10⁹ Ω·cm²的高阻抗、-0.25 V的高腐蚀电位，以及4.119×10⁻¹¹ A·cm⁻²的低腐蚀电流。此外，本文还探讨了聚苯胺/氧化石墨烯环氧涂层的防腐机理。