苯胺/邻甲苯胺微/纳米结构共聚物的合成及防腐性能

Synthesis of aniline/o-toluidine copolymer with micro/nano-structure and its corrosion protection performance

采用化学氧化聚合方法、以不同摩尔比的苯胺与邻甲苯胺共聚,将疏水性基团─CH3引入聚苯胺分子中,制备了一系列具有微/纳米结构的苯胺/邻甲苯胺共聚物。采用红外光谱、紫外–可见吸收光谱、循环伏安曲线测量、X射线衍射等分析手段表征了苯胺/邻甲苯胺共聚物微/纳米结构,并通过扫描电镜(SEM)对其形貌进行了分析。与聚苯胺和聚邻甲苯胺均聚物进行对比,通过Tafel极化曲线和电化学阻抗谱测定了不同摩尔比的苯胺/邻甲苯胺共聚物在0.1 mol/L H2SO4溶液中的腐蚀行为,测试了不同涂层的水接触角。结果表明,─CH3的引入增大了涂层的水接触角,使苯胺/邻甲苯胺共聚物的防腐蚀性能优于聚苯胺。当苯胺、邻甲苯胺按1∶1摩尔比共聚时,得到的苯胺/邻甲苯胺共聚物有一定的结晶性,对水的接触角最大(为65°),且防腐性能最佳,防腐蚀效率达91.1%。

A series of aniline/o-toluidine copolymers with micro/nano-structure were prepared by chemical oxidation polymerization of aniline and o-toluidine with different molar ratios to introduce the hydrophobic group --＇CH3 in polyaniline molecule. The micro/nano structures of the copolymers were characterized by IR spectroscopy, UV-visible absorption spectroscopy, cyclic voltammetry, and X-ray diffraction, and the morphologies were analyzed by scanning electron microscopy （SEM）. In comparison with polyaniline and poly-o-toluidine homopolymers, the corrosion behavior of the copolymers with different molar ratios of aniline to o-toluidine in 0.1 mol/L H2SO4 solution was studied by Tafel polarization curve measurement and electrochemical impedance spectroscopy （EIS）. The contact angles of water on the coatings were determined.Results indicated that the water contact angles of the coatings are improved by the introduction of---CH3 groups, resulting in an improved corrosion protection of the copolymer as compared with that of polyaniline. The copolymer obtained with 1：1 （molar ratio） aniline and o-toluidine has a maximum water contact angle of 65~ and shows a certain crystallinity and the best corrosion protection with a corrosion protection efficiency reaching 91.1%.