以工业级水玻璃为硅源, 水为反应物及溶剂, 经酸碱两步催化, 在45 ℃常压干燥制备了SiO2气凝胶, 对其结构与性能进行了表征, 研究了氨水浓度、水解时间、溶胶pH值对凝胶时间和气凝胶性能的影响。结果表明: 该方法制备的SiO2气凝胶具有典型的气凝胶结构特征, 孔洞尺寸和比表面积分别为8～12 nm、353～613 m2·g-1, 粒径为10～20 nm, 密度0.108～0.15 g·cm-3, 导热系数0.021 08 W·m-1·K-1, 具有高保温性能。

Using industrial grade sodium silicate as silicon source and water as reactant and solvent, SiO2 aerogels were prepared by two-step acid-base catalysis and dried at ambient pressure, 45 ℃. The aerogel structure and properties were characterized. The effects of ammonia concentration, time of hydrolysis, pH value on the gel time and the aerogel properties were studied. Results show that the prepared SiO2 aerogel had typical aerogel structure characteristics and high thermal insulation properties, with the pore size of 8-12 nm, the specific surface area of 353-613 m2·g-1, particle diameter of 10-20 nm, the density of 0.09-0.15 g·cm-3, the thermal conductivity of 0.021 08 W·m-1·K-1.