亚临界干燥制备Sio2气凝胶

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１０ｎｍ，平均孔径为１４．５ｎｍ）和大比表面积（约７０８．３ｍ＾２．ｇ＾－１）。由于亚临界干燥使得制备压力从６．４ＭＰａ降低到

Sio2 Aerogels Dried at Subcritical Condition

Crack- free SiO2 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 SiO2 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 m2·g-1), which are similar with SiO2 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.