Research of silica aerogels prepared by acidic silica sol under the condition of atmospheric pressure drying

Abstract

Acidic silica sol was used as precursor to prepare SiO2 aerogels using the atmospheric pressure drying technology. The influence of pH, water bath temperature and concentrations of silica sol on the structure parameters and morphology were systematically studied. SiO2 aerogel prepared with the sol concentration of 20% possessed uniform structure and the best structure parameters. Water bath temperature exhibited an obvious effect on morphology, specific surface area and porosity. Moreover, the optimal SiO2 aerogel showed a good heat resistance up to 700 °C. A lower thermal conductivity was 0.019 W/m · K at room temperature (25 °C) and 0.044 W/m · K at 600 °C.