摘要
目的 解决Q235钢的腐蚀问题,研究开发一种智能防腐涂层。方法 以乙烯基三乙氧基硅烷、丙烯酸和丙烯酸羟丙酯为单体,采用自由基聚合法制备一种装载缓蚀剂苯并三氮唑(BTA)的pH敏感性有机-无机杂化凝胶BTA@PHVA/PEI,通过扫描电子显微镜(SEM)、傅里叶红外光谱(FT-IR)、热重/差热分析(TGA/DSC)和紫外可见光谱(UV-vis)分别对BTA@PHVA/PEI的形态、结构、热稳定性及pH敏感性进行表征。通过将BTA@PHVA/PEI粉末分散到醇酸树脂漆中,在Q235钢样品表面制备一种智能防腐涂层。先后通过电化学阻抗谱(EIS)、Tafel极化曲线对智能涂层在NaCl腐蚀介质中的自修复性能进行研究,通过盐雾加速腐蚀试验对智能涂层的防腐性能进行评价,并探讨智能涂层的自修复机理。结果 BTA@PHVA/PEI释放BTA的速率随环境pH值的升高而增大,在pH值为2.0、7.0和11.0的溶液中,BTA的32 h累积释放率分别为68.78%、74.51%和91.02%。BTA@PHVA/PEI在智能涂层中的最佳掺杂量为10%。结论 基于BTA@PHVA/PEI的智能防腐涂层对Q235钢具有显著的自修复防腐性能,且在其他金属材料上也具有潜在应用价值。其机理为涂层中掺杂的BTA@PHVA/PEI可响应因腐蚀而导致的pH值变化,释放出BTA分子并被吸附到Q235钢表面成膜,从而抑制腐蚀的进一步发展。
Abstract
The work aims to study a smart anti-corrosion coating to solve the corrosion problem of Q235 steel. Firstly, the pH-sensitive organic-inorganic hybrid hydrogel of BTA@PHVA/PEI preloaded with the inhibitor benzotriazole was prepared through free radical polymerization method with triethoxyvinylsilane, acrylic acid and hydroxypropyl acrylate as the monomers. The morphology, structure, thermostability and pH-sensitivity of BTA@PHVA/PEI were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric/differential scanning calorimetry analysis and ultraviolet-visible spectroscopy, respectively. Afterwards, a smart anti-corrosion coating was fabricated on Q235 steel by the dispersion of BTA@PHVA/PEI into alkyd resin. The self-healing performance of the smart coating in the corrosion medium of NaCl was investigated via electrochemical impedance spectroscopy and Tafel polarization curve in sequence. The anti-corrosion performance of the smart coating was evaluated by the salt spray tests. Meanwhile, the self-healing mechanism of the smart coating was also discussed. The releasing rate of BTA from BTA@PHVA/PEI rose with the increase of the external environment pH values. The cumulative releasing rate of benzotriazole for 32 h immersion in the solution with the pH values of 2.0, 7.0 and 11.0 was 68.78 wt%, 74.51 wt% and 91.02 wt%, respectively. The optimal content of BTA@PHVA/PEI doped into the smart coating was 10 wt%. The self-healing and anti-corrosion performance of the smart coating based on BTA@PHVA/PEI for Q235 steel are remarkable, which can be also used for corrosion protection of other metallic materials.The self-healing mechanism of the smart coating is that BTA@PHVA/PEI doped into the coating can release benzotriazole molecules response to the corrosion-induced changes of pH values. The released benzotriazole molecules can form an adsorptive film on the steel for preventing the corrosion development.
关键词
pH敏感性;杂化凝胶;智能涂层;腐蚀防护;Q235钢;电化学阻抗谱
Key words
pH-sensitivity; hybrid hydrogel; smart coating; corrosion protection; Q235 steel; electrochemical impedance spectroscopy
文家新, 刘云霞, 张欣, 周永福, 刘克建.
基于pH敏感性杂化凝胶BTA@PHVA/PEI的智能防腐涂层研究[J]. 表面技术. 2020, 49(11): 277-287
WEN Jia-xin, LIU Yun-xia, ZHANG Xin, ZHOU Yong-fu, LIU Ke-jian.
Smart Anti-corrosion Coating Based on the Hybrid Hydrogel of BTA@PHVA/PEI with pH-sensitivity[J]. Surface Technology. 2020, 49(11): 277-287
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基金
重庆市自然科学基金面上项目(cstc2020jcyj-msxmX3461)