亚临界干燥制备SiO_2气凝胶  

SiO_2 Aerogels Dried at Subcritical Condition

作　　者：魏建东[1] 邓忠生[1] 薛小松 王珏[1] 

机构地区：[1]同济大学物理系,上海200092

出　　处：《同济大学学报（自然科学版）》2000年第5期575-578,共4页Journal of Tongji University:Natural Science

基　　金：上海市启明星跟踪计划资助!项目 ( 98QME1 4 0 6)

摘　　要：以E - 40 (多聚硅氧烷 )为硅源 ,HF为催化剂 ,采用异丁醇为干燥介质 ,用溶胶凝胶法在亚临界条件下制备了SiO2 气凝胶 .用扫描电子显微镜 (SEM)、孔径分布测定仪、比表面积测试 (BET)等方法对其微结构进行了研究 .结果表明 ,所制备的SiO2 气凝胶具有纳米网络结构 (平均颗粒大小约 1 0nm ,平均孔径约 1 4.5nm)和大比表面积(约 70 8.3m2 ·g- 1 ) .由于亚临界干燥使得制备压力从 6.4MPa降低到 2 .3MPa ,降低了制备成本 ,从而有利于气凝胶的商业应用 .Crack-free SiO 2 aerogels are repeatedly obtained at subcritical condition dried with iso-butanol. The microstructure and properties of the silic aerogel are measured by using pore size distribution, SEM and BET techniques. The results show that the SiO 2 aerogels prepared at subcritical condition have nano microstructure (mean particle size: 10 nm; mean pore radius: 14.5 nm)and large specific suface area (about 708.3 m 2·g -1 ), which are similar with SiO 2 aerogels prepared at supercritical condition. Because of the significant reduction of drying pressure from 6.4 MPa to 2.3 MPa, the manufactory price of the silic aerogels can be reduced and so it is more suitable for its large scale production and application.

关 键 词：亚临界干燥 溶胶--凝胶 二氧化硅气凝胶 

分 类 号：O648.1[理学—物理化学]