Method for preparing low-density high-performance SiO2 aerogel at constant pressure

A low-density, aerogel technology, applied in the direction of silicon dioxide, silicon oxide, etc., can solve the problems of high cost of supercritical drying, high drying density, high thermal conductivity, and expensive silicon source.

Inactive Publication Date: 2012-08-22
陕西得波材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Existing SiO 2 In the preparation of airgel, there are problems of high cost of supercritical drying and complicated process; high density and thermal conductivity of normal pressure drying; expensive silicon source

Method used

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  • Method for preparing low-density high-performance SiO2 aerogel at constant pressure
  • Method for preparing low-density high-performance SiO2 aerogel at constant pressure
  • Method for preparing low-density high-performance SiO2 aerogel at constant pressure

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Experimental program
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Effect test

Embodiment 1

[0020] A low-density SiO prepared under atmospheric pressure 2 The method of airgel, comprises the following steps:

[0021] 1), two-step sol-gel method, the mixed solution of industrial water glass and deionized water is ion-exchanged with cation exchange resin to remove Na + Finally, the pH value was adjusted to 1 with 1mol / L HCl to obtain a sol, and the sol was left to stand for 10 hours, and then NH 3 ·H 2 O adjusted the pH value to 5 to obtain a wet gel,

[0022] 2), step-by-step aging and solvent exchange, put the wet gel in the aging solution mixed with ethyl orthosilicate and ethanol for aging for 1d, the mass ratio or volume ratio of the wet gel and the aging solution is 1:1-2 , place the aged wet gel in n-hexane for solvent exchange for 3d, the mass ratio or volume ratio of the aged wet gel to n-hexane is 1:1-2, the aging and solvent exchange process is: aging 2d-solvent exchange 1d-aging 2d-solvent exchange 2d, the ratio of aging solution V(TEOS):V(EtOH) is 3:7 ...

Embodiment 2

[0027] A low-density SiO prepared under atmospheric pressure 2 The method of airgel, comprises the following steps:

[0028] 1), two-step sol-gel method, the mixed solution of industrial water glass and deionized water is ion-exchanged with cation exchange resin to remove Na + Finally, the pH value was adjusted to 1.5 with 1mol / L HCl to obtain a sol, which was allowed to stand for 11 hours, and then NH 3 ·H 2 O adjusted the pH value to 5.5 to obtain a wet gel,

[0029] 2), step-by-step aging and solvent exchange, place the wet gel in the aging solution mixed with ethyl orthosilicate and ethanol for aging for 3 days, the volume ratio of the wet gel and the aging solution is 1:1-2, and the aging After the wet gel is placed in n-hexane for solvent exchange for 3 days, the volume ratio of wet gel and n-hexane after aging is 1:1~2, and the aging and solvent exchange process is: aging 2d-solvent exchange 1d-aging 2d-solvent Exchange 2d, the ratio of aging solution V(TEOS):V(EtOH...

Embodiment 3

[0034] A low-density SiO prepared under atmospheric pressure 2 The method of airgel, comprises the following steps:

[0035] 1), two-step sol-gel method, the mixed solution of industrial water glass and deionized water is ion-exchanged with cation exchange resin to remove Na + Finally, the pH value was adjusted to 2 with 1mol / L HCl to obtain a sol, which was allowed to stand for 12 hours, and then NH 3 ·H 2 O adjusted the pH value to 6 to obtain a wet gel,

[0036]2), step-by-step aging and solvent exchange, place the wet gel in the aging solution mixed with ethyl orthosilicate and ethanol for aging for 6 days, the volume ratio of the wet gel and the aging solution is 1:1-2, and the aging After the wet gel is placed in n-hexane for solvent exchange for 3 days, the volume ratio of wet gel and n-hexane after aging is 1:1~2, and the aging and solvent exchange process is: aging 2d-solvent exchange 1d-aging 2d-solvent Exchange 2d, the ratio of aging solution V(TEOS):V(EtOH) is ...

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Abstract

The invention discloses a method for preparing low-density high-performance SiO2 aerogel at constant pressure, which comprises the following steps of: performing ion exchange to mixed solution of industrial water glass and deionized water with cation exchange resin by using a two-step method of sol-gel so as to remove Na<+>; adjusting a pH value by using HC1 to obtain sol; keeping stand of the sol and adjusting the pH value by using NH2.H2O to obtain wet gel; carrying out fractional aging and solvent exchange; putting the wet gel into aging liquid which is obtained by mixing ethyl orthosilicate and ethanol for aging; putting the aged wet gel into normal hexane for carrying out solvent exchange; performing surface modification; putting the wet gel subjected to the solvent exchange into mixed liquid of trimethylchlorosilane and normal hexane for performing surface modification; and finally, drying the mixture at the constant pressure and putting the wet gel subjected to the surface modification into normal hexane for drying at the constant pressure. The method has the advantages of low preparation process cost, excellent product performance and controlled reaction process.

Description

technical field [0001] The present invention relates to SiO 2 The field of preparation of aerogels, specifically relating to the preparation of low-density SiO at normal pressure 2 Airgel method. Background technique [0002] SiO 2 The preparation method of airgel is mainly based on sol-gel method, using ethyl orthosilicate, methyl orthosilicate and polysilane as the silicon source, through gel aging, surface modification and other processes, supercritical or normal Airgel was obtained by pressing and drying. [0003] In general, existing SiO 2 The preparation method of airgel can be roughly divided into supercritical drying and low-cost normal pressure drying due to different drying methods. The supercritical drying method is used to remove the residual liquid in the gel by using the high solubility of the liquid in the supercritical state. The solution does not change the structure of the gel, thereby obtaining a porous, disordered, low-density amorphous solid-state m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/16
Inventor 耿刚强刘新军康爽陈安成李凯毕伟涛
Owner 陕西得波材料科技有限公司
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