Study on Preparation of Silica Aerogels Derived from Silica Sol

Abstract

Research on preparation of nanoporous silica aerogels that using cheap silica sol as silica source, undering atmospheric drying. Using orthogonal test method study the different components how to influence the gel time and the aerogel density and obtaining the best ratio. Also study the different PH value how to influence the gel time, aerogel density and the micro-structure. The results showed that: in Silica Sol, ethanol and water system, the ratio of silica sol and alcohol has significantly affected on gel time and aerogel density, the best volume ratio is 1:3, PH from 2 to 5 aerogel density is about 0.32g/cm3, but the gel time decreases rapidly, PH from 5 to 7 aerogel density increases to 0.4g/cm3 quickly, and gel time changes a little, SEM showed that the micro-structure of aerogel is the best when the PH is 5. The non-critical drying method of cheap preparation comes true.