| The research of the transparent insulation materials is a hot issue in the society.Silica aerogel has low thermal conductivity and great thermal insulation properties.Therefore, the silica aerogel with hight transmittance has great t application value and market prospect in the field of solar erergy.By adjusting the gelation temperature, the solvent volume of N, N-dimethyl formamide in the alkali catalyzed process, the molar ratio of water and N-methyl silicate in the catalytic process to explore the impact of these conditions on the silica aerogels preparation. The preparation of the silica aerogel used the traditional acid-base catalyzed sol- gel method, combined with the supercritical carbon dioxide drying technology. The properties of the samples were preliminary researched by line viscometer, rheometer, laser particle size analyzer, field emission scanning electron microscope, Nitrogen adsorption analyzer and UV-visible spectrophotomete. The specific results were as follows:(1) We got the optimal amount of water and the amount of ammonia by exploring the amount of water and ammonia in the process of alkali catalysis. The optimum volume ratio of deionized water and ammonia was50:3. We explored the effect of the gel temperature on the silica sol-gel process and the silica gel colloidal particle diameter at the optimum volume ratio of the deionized water and ammonia. Then we explored the effect of the gel temperature on the corresponding silica topography and the light transmittance.(2) We changed the volume of the N, N- dimethylformamide in the base-catalyzed process under the best volume ratio of deionized water and ammonia and its optimal gel temperature. The sample density changed with the volume of the N, Ndimethylformamide. We studied the effect of the density on the silica sol-gel precess and its gel point. At the same time, we also explored its influence on the silica aerogel morphology and light transmittance.(3) We got different active siloxane precursors by changing the the molar ratio of the deionized water and TMOS in acid catalyzed reaction of acid-base catalysis sol-gel method. We studied its effect on the silica sol-gel process, the morphology and light transmittance of the sample.Through the various studies, we concluded that the sample quality was the bestwhen the gel temperature was 30 C, the volume of DMF was 6 ml, and the molar ratio of deionized water and n-methyl silicate was 1.4. The transmittance of the sample was up to 92.4% at the wavelength of 800 nm. |
