以正硅酸乙酯(tetraethoxysilane,TEOS)、甲基三乙氧基硅烷、二甲基二乙氧基硅烷和甲基丙烯酰氧基丙基三甲氧基硅烷为原料,采用溶胶–凝胶法在聚碳酸酯(polycarbonate,PC)表面上制备透明硬质的SiO2/有机硅复合涂膜。用红外光谱、紫外光谱,热重、X射线衍射、表面扫描电镜、原子力显微镜和接触角测量仪等方法对产物进行了表征。结果表明:复合膜中形成了Si—O—Si网络结构;采用浸涂工艺,经120℃热固化制备的涂膜厚度为0.84μm,表面平整,致密均质,对PC基材具有一定的增透作用(透光率提高了将近5%);复合膜对水的接触角随固化时间的延长而增大,在120℃固化3 h后接触角为93°;随着TEOS含量增加,复合膜的耐热性得到提高;当SiO2/有机硅复合树脂的n(R)/n(Si)(一个硅原子上平均连结的有机基团数目)值选择0.78,划格法测定的复合膜的铅笔硬度为2 H,附着力为0级。
The transparent and hard SiO2/organosilicone hybrid coatings were prepared on polycarbonate(PC) with tetraethoxysilane(TEOS),methyltriethoxysilane,dimethyldiethoxysilane and 3-(methacryloxypropyl)-trimethoxysilane as the main raw materials by the sol–gel method.The structure and properties of the hybrid coating were characterized by Fourier transformed infrared,ultravio-let-visible spectroscopy,thermogravimetric analysis,X–ray diffraction,scanning electron microscopy,atomic mechanics microscope,contact angle measuring instrument,and hardness tester etc.It is found that the basic structure of the hybrid coating is Si—O—Si.After heat-cured at 120 ℃,the thickness of the hybrid coating is 0.84 μm by dipping-withdrawing manner.The hybrid coating is smooth,homogenous and densified,and can improve the transparency of PC(transmittance is increased by nearly 5%).The contact angle of the hybrid coating to the water increases with the increase of curing time.The contact angle is 93°after heat-cured at 120 ℃ for 3 h.The hybrid coating has excellent thermal stability,which increases gradually with the increase of TEOS content.When the mole ratio of R(organic groups) and Si in SiO2/organosilicone hybrid resin is 0.78,the adhesion strength of hybrid coating on PC sheet is 0 class(cross-cut tape test),and it reaches a pencil scratch hardness of 2H.