Enhanced ultralow density aerogel composite material as well as preparation method and application thereof

Abstract

The invention provides a preparation method of an enhanced ultralow density aerogel composite material, comprising the steps of adding and mixing a silicon source, methyl alcohol and hydrochloric acidfor reaction, distilling off the methyl alcohol, then adding acetonitrile to obtain a sol precursor; mixing the sol precursor and ammonium hydroxide, adding acetonitrile again to obtain a silicon dioxide sol; successively performing gelatinization and aging on the silicon dioxide sol to obtain a wet gel composite material; performing hydrophobic treatment on the wet gel composite material with ahydrophobing agent to obtain a hydrophobic gel composite material; performing solvent replacement on the hydrophobic gel composite material to obtained a solvent-replaced gel composite material; adding the solvent-replaced gel composite material into a drying kettle for supercritical drying, so as to obtain the enhanced ultralow density aerogel composite material. The aerogel composite material prepared by the invention has the maximum full size of 300 mm x 300 mm, the thickness of 10 mm to 30 mm, the density of less than 28 kg / m<3>, the size shrinking percentage of less than 1%, and the condensable volatiles of not higher than 0.1%. The invention further provides the enhanced ultralow density aerogel composite material prepared by the method and the application thereof in the field of deep space exploration.

Description

technical field [0001] The invention belongs to the field of thermal protection, in particular to the technical field of thermal protection materials for thermal control systems used in deep space exploration, and specifically relates to an enhanced ultra-low density airgel composite material and its preparation method and application. Background technique [0002] Airgel material is a new type of low-density nanoporous material. It is the solid material with the best thermal insulation performance. Airgel is formed by the mutual accumulation of nanoparticles and has a three-dimensional network nanoporous structure. The Lawrence Livermore National Laboratory of the United States was the first to achieve a breakthrough in the preparation of ultra-low-density silica airgel, and the density of the prepared airgel material can be as low as 3kg / m 3 . The U.S. Jet Propulsion Laboratory used the laboratory technology to realize the application of ultra-low-density aerogels in the ...

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Problems solved by technology

[0003] However, domestic research on ultra-low-density aerogels focuses on small samples and performance research in the laboratory, and there are no reports on the application of large-scale materials.

This preparation technology also has the following disadvantages: 1) the product size shrinkage rate is 15%, and the size shrinkage will bring greater difficulty to the size control in material application; 2) the product yield is low, and the literature reports only have about 25%, resulting in Product production efficiency is low, cost is high; 3) this preparation method can only use supercritical ethanol drying technology, in supercritical CO 2 Under these conditions, ultra-low density aerogels are prone to cracks and become powder materials.

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