MBT插层的CaAl-LDH对水性环氧树脂涂层耐腐蚀性能的提升作用

Improvement of the corrosion resistance performance of waterborne epoxy resin coatings by 2-mercaptobenzothiazole (MBT) intercalated Ca-Al layered double hydroxides

采用离子交换法制备了2-巯基苯并噻唑(MBT)插层的CaAl层状双氢氧化物(CaAl-MBT^(-)-LDH),并将其添加到水性环氧树脂中以提高水性涂料的耐腐蚀性。利用X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)和扫描电子显微镜(SEM)对CaAl-MBT^(-)-LDH进行了表征,结果表明缓蚀剂MBT成功插入LDH层间,CaAl-MBT^(-)-LDH具有类似六边形的结构。通过盐雾试验和浸泡试验评价了添加一定量CaAl-MBT^(-)-LDH粉末的环氧树脂涂层的耐腐蚀性能,结果表明,当0.08 mol/L MBT制备的CaAl-MBT^(-)-LDH(CaAl-MBT_(0.08M)^(-)-LDH)在环氧树脂中的添加量为2%(质量分数)时,环氧树脂涂层经过盐雾试验170 h后依然没有严重的腐蚀痕迹。在3.5%(质量分数)NaCl溶液中浸泡13 d后,添加2%CaAl-MBT_(0.08M)^(-)-LDH的环氧树脂涂层的界面电荷转移电阻(R_(ct))仍高达1.922×10^(6)Ω·cm^(2),而纯环氧树脂涂层的R_(ct)仅为1.621×10^(3)Ω·cm^(2)。以上结果表明,在环氧树脂中添加一定量的CaAl-MBT^(-)-LDH粉末有助于提高水性涂层的耐腐蚀性能。

Ca-Al layered double hydroxides(CaAl-MBT^(-)-LDH)intercalated with 2-mercaptobenzothiazole(MBT)have been prepared by an ion-exchange method and added to epoxy resin in an attempt to improve the corrosion resistance of waterborne coatings.The CaAl-MBT^(-)-LDH was characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR)and scanning electron microscopy(SEM).The results showed that the corrosion inhibitor MBT was successfully intercalated into the LDH interlayer galleries,and CaAl-MBT^(-)-LDH had a hexagonal-like platelet morphology.The corrosion resistance of epoxy resin coatings with a certain amount of CaAl-MBT^(-)-LDH powder was evaluated by salt spray tests and immersion tests.The results showed that when the amount of CaAl-MBT^(-)-LDH(CaAl-MBT_(0.08M)^(-)-LDH)prepared with 0.08 mol/L MBT in epoxy resin was 2%(mass fraction),the coating showed no significant corrosion after 170 h of salt spray testing.After immersion in 3.5%(mass fraction)NaCl solution for 13 d,the interfacial charge transfer resistance R_(ct) of the epoxy coating with 2%CaAl-MBT_(0.08M)^(-)-LDH remained as high as 1.922×10^(6)Ω·cm^(2),while that of the pure epoxy coating was only 1.621×10^(3)Ω·cm^(2).The above results show that the addition of a certain amount of CaAl-MBT^(-)-LDH powder to epoxy resin can help to improve the corrosion resistance of waterborne coatings.