摘要
在醇氨反应体系中 ,根据溶液在不同反应时刻电导率和粘度的变化 ,结合微观形貌观察 ,研究单分散球形SiO2 的形成过程。研究表明单分散球形SiO2 的形成经历 3个阶段 :晶核形成期 ,反应初期正硅酸乙酯在氨催化下快速水解 ,形成大量晶核 ,电导率和粘度迅速增加 ;晶核生长期 ,形成的晶核经聚集不断长大发育 ,电导率逐渐下降 ,粘度不断增加 ;颗粒稳定期 ,颗粒长大后 ,溶液电导率和粘度不再变化 ,而颗粒形态不够完整 ,经过一定时间的稳定发育后 ,最终形成结构密实的单分散球形SiO2 。研究还表明 。
Monodispersed spherical silica was produced in ethanol-ammonia reaction system. Based on the examination of conductivity, viscosity, TEM of reaction system in different stages, it was found that the formation of monodispersed spherical silica experienced three stages.The first was the micro-nuclei formation stage, when tetraalkoxysilane hydrolyzed rapidly in alcoholic-water solutions catalyzed by ammonium hydroxide, a plenty of nuclei was formed, and at the same time the conductivity and viscosity went up rapidly. The second was nuclei growth, when small nuclei condensed and grew continuously, meanwhile the conductivity was decreased gradually and the viscosity was still increased. The last was steady particale when particles reached their full size, and turned more stable and dense. Both the conductivity and viscosity did not varied any more. It shows that the key of producing uniform particles is fast formation and separation of nuclei and growth processes.
出处
《硅酸盐通报》
CAS
CSCD
2003年第1期88-91,共4页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金资助项目 ( 5 0 0 42 0 0 8
5 0 2 0 2 0 14 )
