甲基改性硅溶胶的制备与疏水性分析

Preparation and hydrophobicity analysis of methyl-modified silica sol

通过溶胶−凝胶工艺,以甲基三甲氧基硅烷(MTMS)为基料对碱性硅溶胶进行改性,将改性后的硅溶胶涂覆在铝板表面,制备出具有低表面能、耐高温的含硅透明疏水涂层。考察了pH和热处理温度对涂层水接触角的影响,以傅里叶变换红外光谱仪对涂层进行了表征,用同步热分析仪对比研究硅溶胶和改性硅溶胶干燥后在空气中的热重−差热(TG-DTA)曲线。结果表明,当MTMS与硅溶胶的质量比为9∶10,pH为3.0~3.5,热处理温度为180℃时,改性硅溶胶涂层性能最好,其铅笔硬度大于6H,水接触角为98°,耐温性高达500℃。

An alkaline silica sol was modified by sol-gel method with methyltrimethoxysilane(MTMS),and then used to form a transparent and hydrophobic coating with low surface energy and high temperature resistance on aluminum.The effects of pH and heat treatment temperature on water contact angle of the coating were examined,and the coating was characterized by Fourier-transform infrared spectrometer.The thermogravimetric and differential thermal analytical(TGDTA)curves of unmodified and modified silica sols after being dried in air were studied using synchronous thermal analyzer.The results showed that the modified silica sol coating prepared at a MTMS-to-silica-sol mass ratio of 9:10 and pH 3.0-3.5 after being treated at 180℃ has the best performance:pencil hardness higher than 6H,water contact angle 98°,and heat resistance as high as 500℃.