块体气凝胶的通用制备方法进展

传统溶胶凝胶法、环氧化物法和无机分散溶胶凝胶法是3种用于制备氧化物气凝胶的通用方法，在各自适用范围内均有重要意义。对于块体气凝胶的制备，传统溶胶凝胶法的工艺和理论成熟但制备范围较窄，环氧化物法制备范围广却存在着气凝胶的密度较高、易于收缩、难以成型等缺点，且难以适用于低价态元素氧化物块体气凝胶的制备。无机分散溶胶凝胶法的制备范围则非常广，它采用金属无机盐为前驱体，低分子量聚丙烯酸为分散剂与引导剂，结合传统溶胶凝胶法与环氧化物法，辅以超临界流体干燥和热处理工艺，一步反应即可获得具有密度较低、成型性好、强度较高、杂质易去除等特点的块体气凝胶。该方法可广泛应用于多族多周期块体气凝胶的制备，在气凝胶的制备与应用领域将拥有广阔的前景。

Progress on Universal Methods to Prepare Monolithic Aerogels

The traditional sol-gel (TS) method, epoxide (EP) method and dispersed inorganic sol-gel (DIS) method which are the main synthetic routes to the multi-group and multi-period monolithic aerogels are very significant in their application fields, respectively. Given its advantages in preparing monolithic aerogels, the DIS method is focally introduced. The DIS method uses the inorganic metal salt as precursor (avoiding the use of the metal alkoxide), as well as the low molecular weight polyacrylic acid as dispersant and template, followed by aging and supercritical fluid drying, to prepare various (multi-periods and multi groups) well formed and high-strength monolithic aerogels, combining the advantages of traditional sol-gel method and epoxide method. And the impurities of the aerogels can be easily removed via a thermal treatment. Based on those above, the DIS method is hopeful to be an accepted universal method on aerogels preparation and has good application prospects.