亚临界干燥制备疏水SiO_2气凝胶

以Ｅ－４０（多聚硅氧烷）为硅源、三甲基氯硅烷的异丁醇溶液为干燥介质，用溶胶凝胶法，在亚临界条件下制备出疏水的ＳｉＯ２气凝胶．通过ＳＥＭ、孔径分布、比表面积、接触角以及红外光谱的测试对其物性进行了研究．结果表明，所制备的ＳｉＯ２气凝胶具有典型的纳米网络结构、比表面积大且具有疏水性能．亚临界干燥使得制备压力从６．４ＭＰａ降低到２．３ＭＰａ，降低了制备成本和风险，同时疏水性能提高了ＳｉＯ２气凝胶环境适应性，从而十分有利于气凝胶的商业应用．

Hydrophobic SiO_2 Aerogels Dried at Subcritical Condition

Crack-free and hydrophobic SiO2 aerogels were repeatedly obtained at subcritical condition dried with iso-butanol, which were modified by TMCS. The microstructure and properties of the silica aerogel were measured by pore size distribution, SEM, IR, contact angle and BET techniques. The results show that the SiO2 aerogels prepared at subcritical conditions have classical nano microstructure(mean particle size: 10nm; mean pore radius: 14.5nm), large specific surfacal area (about 708.3m2/g). Because of the significant reduction of drying pressure from 6.4MPa to 2.3MPa, the manufactory price of the silica aerogels can be reduced. On the other hand, it is hydrophobic, which can be used widely. So it is more suitable for large scale production and application.