石墨烯对镁合金表面聚苯胺/环氧涂层性能的影响

Effect of Graphene on the Performance of Polyaniline/Epoxy Coating on Magnesium Alloy Surface

为研究不同石墨烯添加方式对聚苯胺/环氧涂层性能的影响,通过原位聚合法在石墨烯表面合成聚苯胺,并利用X射线衍射仪、傅立叶变换红外光谱仪、扫描电子显微镜对聚合的粉末进行表征。分别将合成的聚苯胺/石墨烯聚合粉末、聚苯胺与石墨烯的混合粉末、聚苯胺粉末分散于环氧树脂中,在AZ91D镁合金表面制备涂层,通过电化学阻抗测试、吸水率等研究不同石墨烯添加方式对聚苯胺/环氧涂层性能的影响。研究结果表明:在3.5%(质量分数)NaCl溶液中浸泡2160 h内,加入聚苯胺/石墨烯聚合粉末涂层的阻抗值一直高于加入聚苯胺涂层和聚苯胺石墨烯混合粉末涂层的,且该涂层具有更好的柔韧性和耐冲击性能。与直接混合方式相比,原位聚合后的聚苯胺/石墨烯聚合粉末能够更好地发挥石墨烯的屏蔽作用和聚苯胺的缓蚀作用,从而对镁合金起到更好的防护效果.

For studying the effects of different addition ways of graphene on the properties of polyaniline/epoxy coatings,the in-situ polymeri-zation method was applied to synthesize polyaniline(PANI)/graphene(G)composite powders on graphene surface,and the as-prepared pow-ders were characterized by X-ray diffractometer,Fourier transform infrared spectrometer and scanning electron microscope.The as-synthesized composite powders,the mixed powders of PANI and G,and the PANI powders were uniformly dispersed in epoxy resin respectively to prepare coatings on the surface of AZ91D magnesium alloy.Subsequently,the effects of different graphene addition methods on the properties of polyan-iline/epoxy coatings were studied through electrochemical impedance measurement,water absorption,etc.Results showed that after an immer-sion within 2160 h in 3.5%(mass fraction)NaCl solution,the coating added with PANI/G composite powders not only had a higher imped-ance value in comparision with those added with PANI powders or with PANI/G powders,but also had better flexibility and impact resistance.Compared with the mixed powders of PANI and G,the PANI/G composite powders obtained through in-situ polymerization could better exhibit the shielding effect of G and the corrosion inhibition effect of PANI,and therefore provid better protection to magnesium alloy.