Supercritical drying method of sodium metaaluminate modified resin purified water-glass aerogel

Abstract

The invention provides a supercritical drying method of sodium metaaluminate modified resin purified water-glass aerogel.Firstly, solvent replacement and hydrophobic modification are conducted on wet gel, then the wet gel subjected to the hydrophobic modification is put into a high-pressure reaction kettle, a supercritical medium is poured into the kettle, the heating temperature is set for heating, and degassing or reflux is performed to bring out the solvent in the wet gel till solvent recovery is completed after the medium in the reaction kettle reaches a supercritical state, wherein the supercritical medium is an acetonitrile, ethanol or carbon dioxide solvent.The product produced by adopting the supercritical drying method is high in product yield and high in production efficiency, slightly comes off and can be subjected to industrialized amplification.The supercritical drying method can be integrated to a production line.The whole preparation method is simple and easy to operate, free of strong acid and alkali corrosion, low in equipment requirement and suitable for industrial production after amplification.

Description

technical field [0001] The invention relates to an airgel drying method, in particular to a supercritical drying method for sodium metaaluminate modified resin purified water glass airgel. Background technique [0002] Airgel is the material with the lowest thermal conductivity among solid substances, which is only slightly higher than vacuum, about 0.013W / m·K. Airgel also has an extremely low density, which is recognized as the least dense solid in the world, and the lowest density can reach 3kg / m 3 , which is slightly denser than air. Therefore, airgel is the thermal insulation material with the best thermal insulation effect and the smallest density in the world. [0003] At present, there are many types of aerogels, including carbon aerogels, silicon-based aerogels, and alumina aerogels. The raw material for the preparation of silica airgel can be tetraethyl silicate or water glass, and the preparation process can use normal pressure method and supercritical method re...

AI Technical Summary

Problems solved by technology

However, the preparation of silica / alumina composite airgel is rarely reported. Even if the composite gel has been prepared, the alkoxide method is used for gelation.

[0004] Tetraethyl silicate is used as the raw material, and the raw material cost is expensive; the sol-gel process is complex, and the process scale-up cost is high

Water glass is used in the prior art, the thermal conductivity and density of the airgel prepared are not ideal, and the process is also complicated

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