掺杂态聚苯胺的乳液聚合及其与环氧树脂所制涂层的耐蚀性

Emulsion polymerization of doped polyaniline and anticorrosion performance of the epoxy coating prepared with it

以十二烷基苯磺酸钠(SDBS)为乳化剂,采用乳液聚合法制备了盐酸或磷酸与十二烷基苯磺酸(DBSA)共掺杂的聚苯胺[(HCl+DBSA)-PANI或(H_3PO_4+DBSA)-PANI]。用扫描电镜、傅里叶变换红外光谱仪、X射线衍射仪和四探针电导率测试仪表征了掺杂聚苯胺的形貌、结构和电导率。将添加了掺杂态聚苯胺的E44环氧树脂刷涂在Q235低碳钢表面得到复合涂层(PANI/EP),并通过电化学阻抗谱和浸泡试验考察了它们在3.5%NaCl溶液中的耐蚀性。两种共掺杂态聚苯胺都呈束状结构,(HCl+DBSA)-PANI的结构更均一。添加PANI可以明显提高环氧涂层对碳钢的防腐作用,其中(HCl+DBSA)-PANI的效果更好。

Polyaniline co-doped by hydrochloric acid or phosphoric acid with dodecylbenzenesulfonic acid （DBSA） [（HCl＋DBSA）-PANI or （H3PO4＋DBSA）-PANI] was synthesized by emulsion polymerization using sodium dodecyl benzenesulfonate （SDBS） as emulsifier. The morphology, molecular structure and electrical conductivity of the doped polyanilines were characterized by scanning electron microscope, Fourier-transform infrared spectroscope, X-ray diffractometer and four-point probe conductivity tester. The E44 epoxy resin mixed with the doped polyanilines was brushed on the surface of Q235 mild steel to form composite coatings （PANI/EP）, whose corrosion resistance were evaluated by electrochemical impedance spectroscopy and immersion test in 3.5% NaCl solution. Both co-doped PANIs present filamentary structure and the structure of （HCl＋DBSA）-PANI is more uniform. The addition of PANI, especially the （HCl＋DBSA）-PANI, greatly enhances the anticorrosion property of epoxy coating for mild steel.