Preparation method of flexible silicon dioxide aerogel

Abstract

The invention discloses a preparation method of flexible silicon dioxide aerogel, which comprises the following steps: S1, dissolving CTAB in a mixed solvent to obtain a mixed solution which comprisesethanol, water and hydrochloric acid; S2, sequentially adding TEOS, MTES and DEDMS into the mixed solution under a stirring condition, and mixing and stirring to obtain silicon dioxide sol; S3, dropwise adding ammonia water with the concentration of 2-3 mol / L into the silicon dioxide sol under a stirring condition, and mixing and stirring to obtain silicon dioxide gel, with the molar ratio of theammonia water to the DEDMS added in the S2 being (0.008-0.012): (0.015-0.025); and S4, carrying out aging treatment, cleaning and drying on the silicon dioxide gel to obtain the flexible silicon dioxide aerogel. The connection strength of an aerogel skeleton can be improved, the preparation time is shortened, and the preparation efficiency is improved.

Description

technical field [0001] The invention relates to the preparation of airgel, in particular to a preparation method of flexible silica airgel. Background technique [0002] Airgel is considered to be the lightest solid material in the world. Due to its ultra-high porosity and unique pore structure, aerogels have many important applications in heat insulation, adsorption and separation, catalysts and catalyst supports, optical devices, and electrical devices. Aerogels mainly include oxide aerogels such as silica, carbon aerogels, cellulose aerogels, etc. These aerogels are usually prepared by using a sol-gel process to prepare wet gels, and then wet gels The aerogels were obtained after the solvent inside was replaced with air. The displacement drying process usually requires supercritical carbon dioxide drying or freeze drying, otherwise the pores in the material will collapse due to capillary force, resulting in the destruction of its skeleton structure. However, supercriti...

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Problems solved by technology

The preparation process is generally to use the sol-gel method to form a branched wet gel with a three-dimensional network structure, and then combine with an appropriate drying process to remove the solution in the gel to obtain an aerogel, but this method has a long time ( Usually more than 2 days), the connection strength of the product skeleton structure is low, etc.

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