纳米二氧化钛硅烷接枝密度对水性环氧涂层耐蚀性能的影响  

Effect of Grafting Density of Nano-TiO2 Silane on Corrosion Resistance of Waterborne Epoxy Coatings

作　　者：安成强[1] 李庆鲁 郝建军[1] AN Cheng-qiang;LI Qing-lu;HAO Jian-jun(School of Environmental and Chemical Engineering,Shenyang Ligong University,Shenyang 110159,China)

机构地区：[1]沈阳理工大学环境与化学工程学院,沈阳110159

出　　处：《表面技术》2020年第3期248-254,339,共8页Surface Technology

摘　　要：目的研究水性环氧/硅烷化纳米TiO2复合防护涂层在3.5%NaCl溶液中的失效规律和防腐性能。方法采用3-氨丙基三乙氧基硅烷(APTES)化学接枝改性纳米TiO2颗粒,将硅烷改性纳米TiO2均匀分散在水性环氧涂料中,并把混合涂料涂覆在Q235钢试样上。采用傅里叶红外光谱仪(FTIR)和热重分析仪(TGA)测试纳米TiO2表面化学接枝改性情况,采用电化学工作站测试复合涂层的电化学性能,采用激光共聚焦显微镜观察复合膜层的表面形貌。结果使用质量分数10%APTES改性纳米TiO2,单齿螺旋结构占有的比例更高;使用质量分数20%APTES改性纳米TiO2,具有最高的接枝密度,为11.78 APTES/nm^2。电化学测试结果显示,环氧/TiO2复合涂层比纯环氧涂层具有更好的耐蚀性能,其中加入质量分数20%APTES改性纳米TiO2的环氧/TiO2复合涂层对基体的保护性能最好,其涂层电阻是纯环氧涂层的12倍,电荷转移电阻是纯环氧涂层的18倍。在相同的腐蚀条件下,单齿螺旋结构更容易被破坏。加入硅烷纳米TiO2颗粒后,可以显著减少涂层表面尖峰状突起和孔洞。结论纳米TiO2的APTES接枝分子密度,是水性环氧/硅烷化纳米TiO2复合防护涂层耐腐蚀性能提高的直接原因。The work aims to study the invaliding laws and corrosion resistance of waterborne epoxy/silanated nano-TiO2 composite protective coating in 3.5%wt sodium chloride solution.The surface of the nano-TiO2 particles was chemically grafted with 3-aminopropyltriethoxysilane(APTES)and uniformly dispersed in a waterborne epoxy coating.The mixed coating was coated on a Q235 steel sample.The chemical grafting modified behavior on the surface of nano-TiO2 was investigated by Fourier transform infrared spectroscopy(FTIR)and thermo gravimetric analyzer(TGA).The electrochemical performance of the composite coating was tested by electrochemical workstation.The morphology of the composite coating was observed by laser confocal microscopy.The chemical grafted structure of nano-TiO2 modified by 10 wt%APTES was mainly the single-tooth spiral structure;while the nano-TiO2 modified by 20 wt%APTES had the highest grafting density of 11.78 APTES/nm^2.The electrochemical test results showed that the epoxy/TiO2 composite coating had better corrosion resistance than the pure epoxy coating and the epoxy/TiO2 composite coating obtained by modifying nano-TiO2 with 20 wt%APTES provided the best protection for the substrate,because the coating resistance was 12 times that of the pure epoxy coating,and the charge transfer resistance was 18 times that of the pure epoxy coating.Under the same corrosion conditions,the single-tooth spiral structure was more easily destroyed.The addition of silaneted nano-TiO2 particles could significantly reduce the peaks and holes in the coating surface.The grafting density of APTES molecular on nano-TiO2 particles is the direct factor to improve the corrosion resistance of waterborne epoxy/silanated nano-TiO2 composite protective coating.

关 键 词：硅烷改性 纳米二氧化钛 水性涂层 环氧涂层 耐蚀性 接枝密度 失效规律 

分 类 号：TG174.4[金属学及工艺—金属表面处理]