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

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1.922×10⁶ Ω·cm²，而纯环氧树脂涂层的R_ct仅为1.621×10³ Ω·cm²。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。

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

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 1.922×10⁶ Ω·cm², while that of the pure epoxy coating was only 1.621×10³ Ω·cm². 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.