Solvent effect on ageing of silica gels
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The structure of silica gels derived from tetraethoxysilane (TEOS) with molar compositions of TEOS∶H2O∶HNO3=1∶10∶0.4 and then aged in various solvents, was studied. The effect of various solvents having different physical properties on the gel structure, as well as the relationship between the solvent properties and the dried gel structure, were investigated. The density, surface area and pore-size distribution were measured. The results of the pore structure and SEM showed the aged gels to have a slit-shaped micropore, narrow pore-size distribution, and homogeneous microstructure. The density, surface area, pore size and pore volume of dried gels changed as the gels were subjected to ageing in various solvents. The surface area could be related to the polarity parameter of the ageing solvent.
KeywordsPolymer Microstructure Pore Size HNO3 Pore Structure
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