Preparation method of silica aerogel

A technology of silica and airgel, applied in chemical instruments and methods, inorganic chemistry, silicon compounds, etc., can solve problems such as increasing equipment airtightness, explosion-proof anti-static, reducing production safety, and cumbersome processes, etc., to achieve Improvement of preparation efficiency, favorable control and simple process

Active Publication Date: 2012-09-19
纳诺科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method directly prepares alcohol gel by adding ethanol to silica sol, but after gelation, it still needs to soak the obtained gel with ethanol solution of different concentrations. For industrial production, an organic solvent is introduced during the preparation of the gel. It is cumbersome, and the introduction of organic solvents during the preparation of the gel increases the requirements for airtightness, explosion-proof, anti-static, etc. of the equipment, which not only increases the cost but also reduces the safety of production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037]Take 100ml of alkaline silica sol with a silica content of 30% (wt) in a 500ml beaker, measure 200ml of water and add it to the beaker to dilute the alkaline silica sol. Slowly drop into the prepared silica sol aqueous solution, and stir while adding, until the pH value of the silica sol aqueous solution reaches 11.4, then titrate the silica sol aqueous solution with 2mol / L HCl solution, and stir while dripping, until the pH value reaches 6.5 , put the dropwise solution in a water bath at 80°C, after 2 hours the solution forms a hydrogel, continue to age in a water bath at 60°C for 2 hours, take out the gel, and replace it with 95% (wt) ethanol, ethanol and water The volume ratio of the gel is 5:1, the replacement temperature is 60°C, and the replacement time is 3 hours. A total of 3 replacements are made to obtain an alcohol gel, which is then supercritically dried with carbon dioxide to obtain hydrophilic SiO 2 airgel.

Embodiment 2

[0039] Take 50ml of alkaline silica sol with a silica content of 30% (wt) in a 500ml beaker, measure 150ml of water and add it to the beaker to dilute the alkaline silica sol. Slowly drop the sodium nitrate solution into the prepared silica sol aqueous solution, and stir while dropping until the pH value of the silica sol aqueous solution reaches 11.2, then titrate the silica sol aqueous solution with 2mol / L HCl solution, and stir while dropping until the pH value reaches 11.2. When the value reaches 7.2, put the dripped solution in a 60°C water bath. After 2min15s, the solution forms a hydrogel, and continues to age in a 60°C water bath for 3h. Take out the gel and replace it in 95% (wt) ethanol. The volume ratio of ethanol to hydrogel is 5:1, the replacement temperature is 60°C, the replacement time is 3h, and the replacement time is 1 time, the gel is taken out and placed in trimethylchlorosilane solution for surface methylation treatment, soaked at 60°C 3h, through ethanol...

Embodiment 3

[0041] Take 50ml of alkaline silica sol with a silica content of 30% (wt) in a 1000ml beaker, measure 200ml of water and add it to the beaker to dilute the alkaline silica sol. Slowly drop the sodium bicarbonate solution into the prepared aqueous silica sol solution, and stir while adding dropwise until the pH value of the aqueous silica sol solution reaches 11.0, and then add 3 mol / L of H 2 SO 4 Solution titration of silica sol aqueous solution, stirring while adding dropwise, until the pH value reaches 6.4, put the dropwise added solution in a 60°C water bath, after 7min15s, the solution forms a hydrogel, continue to age in a 60°C water bath atmosphere for 2.5h, put The gel was taken out and replaced in 95% (wt) ethanol. The volume ratio of ethanol to hydrogel was 5:1, the replacement temperature was 60°C, and the replacement time was 3 hours. Methyl chlorosilane solution was subjected to surface methylation treatment, soaked at 60°C for 3h, and then dried under normal pres...

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PUM

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Abstract

The invention discloses a preparation method of silica aerogel, and belongs to the field of preparation of inorganic porous materials. The preparation method includes: allowing alkaline silica sol to form aerogel directly under the action of acid catalyst and base catalyst; performing solvent displacement and surface silylanizing; and supercritical or atmospheric drying to obtain SiO2 aerogel. Organic solvents are not used in sol formation, and accordingly dangers in sol formation are eliminated. The complex process of sol preparation by organosilicone and desalination by sodium silicate is omitted from the aerogel preparation, the alkaline silica sol low in cost and stable in performance is used as raw material, process is simple, production cycle is short, reaction process is controllable, equipment requirements and investment are low, and industrial production of SiO2 aerogel is achieved.

Description

Technical field: [0001] The invention belongs to the field of preparation of inorganic porous materials, and in particular relates to a method for preparing nanoporous silica airgel by using alkaline silica sol as a raw material. Background technique: [0002] Silicon dioxide (SiO 2 ) Airgel is a new type of lightweight porous material that is formed by the aggregation of nano-scale particles and uses air as the dispersion medium. Its porosity rate is as high as 80%-99%, and the typical size of the pores is 1-100nm. It has the advantages of low refractive index, small Young's modulus, low acoustic impedance, low thermal conductivity and strong adsorption performance. , acoustics, electricity and other aspects show unique properties, and have broad and huge application prospects in aerospace, military industry, communication, medical, building materials, electronics, metallurgy and many other fields. In 2007, the British "Times" praised SiO 2 Aerogels are "magic materials ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/158
Inventor 林芬姜法兴余盛锦张蓉艳
Owner 纳诺科技有限公司
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