一种多硅偶联剂的合成及其耐腐蚀性能

目的开发可独立用于金属表面防护处理的硅烷偶联剂。方法以巯丙基三甲氧基硅烷(MPS)、三乙烯基三甲基环三硅氧烷(TEMS)为反应物,通过巯基-烯烃点击化学反应,合成一种三官能度硅烷偶联剂(TSC,产率95%),在马口铁片表面得到一层致密的偶联剂防护涂层。采用FTIR、1H NMR分析合成产物的化学结构;通过XPS对涂层结构进行分析,并采用SEM对涂层形貌进行了表征;采用热重分析、极化曲线、盐雾腐蚀试验等对TSC水解液固化涂层性能进行表征。结果红外分析表明,反应后原料的双键伸缩振动吸收峰C=C、C—H、S—H均消失,说明发生了反应。核磁谱图(1H NMR)分析表明,产物结构为目标产物TSC。XPS测试结果表明,涂层与金属表面形成了Si—O—Fe共价键。TSC膜层热稳定性能优于MPS水解液膜层。盐雾加速腐蚀实验表明TSC的防护性能明显优于MPS,腐蚀速率为2.60×10-2 mm/a。TSC膜层的硬度达到了5H。SEM分析表明,TSC涂层表面较MPS平整光滑,缺陷少。结论合成了一种多硅偶联剂,该偶联剂经水解后可直接用于马口铁片表面处理与防护,防护涂层性能优异。

Synthesis and Corrosion Resistance of a Multi-silicon Coupling Agent

The work aims to develop a silane coupling agent which can be used for metal surface protection treatment independently.A trifunctional silane coupling agent (TSC,yield 95％) was synthesized based on thiol-ene click chemistry reaction of mercapto-trimethoxysilane (MPS) and trivinyltrimethylcyclotrisiloxane (TEMS).A dense layer of corrosive coupling agent protective coating was obtained on the surface of tinplate.Chemical structure of the synthetic product was characterized with FTIR and 1H NMR.Coating structure was analyzed with XPS,and morphology was characterized with SEM.Properties of the coating cured with TSC hydrolyzate were characterized based upon thermogravimetric analysis,polarization curve,salt spray corrosion test,etc.Infrared results showed that double-bond stretching vibration absorption peaks (Vc=c),(vC-H) and (vS-H) of the raw materials disappeared after the reaction,indicating that the reaction occurred.The 1H NMR analysis showed that the product structure was target product TSC.XPS test results showed that Si—OFe covalent bond formed on the coating and metallic surface.Thermal stability of the TSC coating was better than that of MPS hydrolysate coating.Salt spray accelerated corrosion test indicated that protective properties of TSC was obviously superior to that of MPS,and corrosion rate was 2.60× 10-2 mm/a.Hardness of the TSC coating was up to 5H.SEM analysis showed that the TSC coating surface was smoother and less defective than MPS coating.A multi-silicon coupling agent is synthesized and can be directly used for surface treatment and protection of tinplate after hydrolysis.The protective coating exhibits excellent performance.