Seon-Woo Park1, Byung-Koog Jang2 and Young-Jei Oh1
1Thin Film Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea
The effect of glycerol as a drying control chemical additive for ambient pressure drying of silica aerogel was investigated. Silica hydrosol was prepared by the addition of 0.5～2.0 mass% glycerol to the mixture of metal alkoxide (TEOS) precursor and isopropanol as a solvent. The glycerol additive in silica aerogel is located on the hydroxyls of silica surface and could suppress a formation of crack in silica aerogel during ambient drying. The addition of excess glycerol affected a gelation time and springback effect. Crack-free silica aerogels were obtained. Specific surface area, average pore size, total pore volume, porosity and transparency of the silica aerogel were decreased but bulk density and hydrophobicity were increased as increasing the glycerol contents. Silica aerogel with 1 mass% glycerol addition was showed 0.42 g/cm3 of bulk density, 888 m2/g of specific surface area, 4.6 nm of average pore diameter and 85% of porosity.
ambient pressure drying, drying control chemical additive(DCCA), crack-free, springback effect, gelation
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