Method for preparing transparent silicon dioxide aerogel by co-precursor normal atmosphere drying

Abstract

A method for gelating a co-precursor relates to an aerogel. The invention provides a method for preparing transparent silica aerogel by normal pressure drying through a co-precursor method. The method has the advantages of low cost, simple process, short production cycle, controllable reaction course and continuous production. Tetraethyl silicate and absolute ethyl alcohol are put into a container according to a proportion and stirred, and added with methyl triethoxysilane; added with water and stirred; added with hydrochloric acid to regulate the pH of the solution; added with ammonia water to regulate the pH of the system after stirring; the silica sol is kept stand still after stirring to obtain wet gel; the obtained wet gel is put into a normal hexane solution or a normal hexane solution containing the methyl triethoxysilane with volume concentration of 10%-50% for solvent exchange and aging, after being exchanged by the solution containing the methyl triethoxysilane agent, the gel is washed by the normal hexane solution to remove the methyl triethoxysilane remained on the surface of the sample, and the transparent silica aerogel is obtained by drying.

Description

Technical field [0001] The invention relates to an aerogel, in particular to a method for preparing a transparent silica aerogel by using a co-precursor method to dry under normal pressure. Background technique [0002] Silica (SiO 2 ) Aerogel is a nanoporous material with high specific surface area, high porosity, low density and low thermal conductivity. Its skeleton is a nanoporous spatial network structure. Based on the special properties of the material, SiO 2 Aerogels have very broad application prospects in the fields of optics, electricity, thermal insulation, environmental protection, catalysis, and chemical engineering. Especially SiO 2 The aerogel-based nanoporous composite material has very low thermal conductivity and is a new type of high-efficiency heat insulation material. Its nano network structure can effectively reduce the solid heat conduction of the material, and the nanoporous structure effectively inhibits gas molecules For the effect of heat conduction, by...

AI Technical Summary

Problems solved by technology

In 2007, Te-Yu Wei in Taiwan obtained bulk SiO with better properties through multi-step solvent exchange and surface modification using orthosilicate as a precursor. 2 Airgel, sample porosity 97%, density 0.07g / cm 3 , thermal conductivity 0.036W·(m·K) -1 , the preparation cycle of this method is long, the process is cumbersome, and consumes a large amount of solvent, which limits its practical applicability

Since 2006, South Korea's Sharad.D Bhagat has added a multifunctional surface modifier during the gel formation process, using water glass as a precursor to prepare SiO under an atmospheric pressure drying process 2 Airgel powder, sample specific surface area 473~776m 2 / g, density 0.1~0.309g / cm 3 , the preparation time of this method is short and the process is simple, but the obtained is non-transparent white powder with poor mechanical strength

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