摘要
通过对正硅酸乙酯的两步水解-缩聚反应速率的调控,使生成的醇凝胶具有比较完整的网络结构,经过老化,改善和增强凝胶的结构和强度,配合依次丙酮、正己烷溶剂替换,经过表面修饰,在常压干燥下制备了SiO_2气凝胶,并采用SEM、XRD、BET、傅里叶变换红外光谱仪、激光粒度分析仪等手段对所得气凝胶样品进行表征;BET和SEM测试结果表明,所制备的SiO_2气凝胶具有大的比表面和纳米多孔结构,XRD进一步表明是非晶形,激光粒度仪测试表明其体积平均粒径<20滋m,为介孔结构。
The preparation of silica aerogel under ambient pressure is realized by the following procedures:(1)formation of silica alcogels with perfect network structure by controlling two-step hydrolysis and condensation reaction rates of tetraethoxysilane;(2)improvement and reinforcement of network structure and strength of silica gels through aging; (3) silica gels through exchanging the pore fluid with acetone and hexane in sequence thoroughly;(4)the surface modification. The resulting aerogels were characterized by means of SEM,XRD,BET and laser particle analyzer techniques. SEM, and BET show that the silica aerogels have a high inner surface and porous structure. XRD exactly shows silica aerogels are amorphous. Laser particle analyzer shows the average particle size of silica aerogels are less than 20?滋m. It was mesoporous structure.
出处
《中国陶瓷工业》
CAS
2005年第2期19-21,14,共4页
China Ceramic Industry
关键词
气凝胶
常压干燥
两步法
SIO2
aerogel,drying under ambient pressure,two-step method,SiO2
