纳米SiO2制备及改性

为了改善纳米SiO2的分散性,用溶胶-凝胶技术制备了纳米SiO2凝胶,并用不同改性剂对粉末进行了表面改性.采用透射电子显微镜(TEM)、X射线衍射(XRD)、粒度分析仪(PSA)、紫外-可见光分光光度计(UV-VS)等分析了纳米SiO2的粒径及分散性.结果表明,正硅酸乙酯的水解和缩合反应条件直接影响纳米SiO2粉体的粒径大小.KH-550硅烷偶联改性剂用量、改性时间等因素对改性效果有明显的影响.当改性剂用量为4.1%(质量分数),改性时间为2h时,可得到高分散性的纳米SiO2粉体.纳米SiO2粉末易发生团聚,只有对其进行表面改性,才能得到疏水性纳米SiO2粉末.

Preparation and modification of nano-scale silica

In order to improve the dispersity of nano-silica, nano-silica colloid was prepared by using the sol-gel technology. The process of surface modification to nano-silica powder by different modified agents was conducted. The particle size and dispersity of nano-silica were characterized by using transmission electron microscope (TEM), X-ray diffractometer (XRD), particle size analyzer (PSA) and UV-visible spectrophotometer(UV-VS). The results showed that the hydrolization and condensation of tetraethyl orthosilicate (TEOS) had influence on the particle size of nano-silica. The content and modification time of KH-550 silicane coupling modification agent significantly affected the modification. The best dispersity of nano-silica was observed at modification agent content of 4.1% and modification time of 2 h. To obtain the hydrophobic nano-silica powder, the surface modification to nano-silica powder must be conducted.