Heat-resisting silica aerogel material and preparation method thereof

A silica and airgel technology, applied in the direction of silica and silica, can solve the problems of difficult control of the surface modification process, easy cracking in the drying process, complicated gel process, etc., and achieve strong hardness, high transparency, Effect of high specific surface area and mechanical properties

Inactive Publication Date: 2014-04-30
SHANGHAI NAT ENG RES CENT FORNANOTECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, it is very difficult to prepare bulk silica airgel with water glass as the source, because the gelation process is complicated, the surface modification process is difficult to control, and it is easy to crack during the drying process.
So far, there are few reports on bulk silica airgel materials that can withstand high temperatures of 1000 °C

Method used

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  • Heat-resisting silica aerogel material and preparation method thereof
  • Heat-resisting silica aerogel material and preparation method thereof
  • Heat-resisting silica aerogel material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] The first step is to use methyl silicate, methanol, insufficient water and appropriate amount of hydrochloric acid according to the molar ratio of 1: 2.4: 1.5: 10 -5 mix. The mixed solution was refluxed at 85°C for 20 hours to achieve full mixing and increase the rate of hydrolysis, and then distilled at 95°C for 4 hours to remove the methanol generated by the reaction to obtain partially hydrolyzed and partially polycondensed silica sol (CS), the size of colloidal particles Smaller; the second step reaction is to mix CS with acetonitrile, water and ammonia according to the volume ratio of 1:10: 1.5: 0.025. SiO is obtained after full hydrolysis 2 Sol, and then pour the sol into the mold, after about 20 minutes, the polycondensation reaction forms a uniform and transparent SiO 2 gel. The wet gel was covered with a small amount of alcohol and aged for 1 day, and then replaced with alcohol 3 times for 12 hours each time.

[0031] SiO 2 Put the wet gel into a supercrit...

Embodiment 2

[0034] In the first step, the molar ratio of methyl silicate, methanol, insufficient water and appropriate amount of hydrochloric acid is 1: 3: 1.2: 3×10 -5 mix. The mixed solution was flowed at 85°C for 20 hours to achieve full mixing and increase the rate of hydrolysis, and then distilled at 95°C for 4 hours to remove the methanol generated by the reaction to obtain partially hydrolyzed and partially polycondensed silica sol (CS), colloidal particles The size is small; the second step reaction is to mix CS with acetonitrile, water and ammonia according to the volume ratio of 1:20: 1.6: 0.03. SiO is obtained after full hydrolysis 2 Sol, and then pour the sol into the mold, after about 20 minutes, the polycondensation reaction forms a uniform and transparent SiO 2 gel. The wet gel was covered with a small amount of alcohol and aged for 1 day, and then replaced with alcohol 3 times for 12 hours each time.

[0035] SiO 2 Put the wet gel into a supercritical drying equipment...

Embodiment 3

[0038] In the first step, the molar ratio of methyl silicate, methanol, insufficient water and appropriate amount of hydrochloric acid is 1: 2.8: 1.4: 4×10 -5 mix. The mixed solution was refluxed at 85°C for 20 hours to achieve full mixing and increase the rate of hydrolysis, and then distilled at 95°C for 4 hours to remove the methanol generated by the reaction to obtain partially hydrolyzed and partially polycondensed silica sol (CS), the size of colloidal particles Smaller; the second step reaction is to mix CS with acetonitrile, water and ammonia according to the volume ratio of 1:30: 1.6: 0.03. SiO is obtained after full hydrolysis 2 Sol, and then pour the sol into the mold, after about 20 minutes, the polycondensation reaction forms a uniform and transparent SiO 2 gel. The wet gel was covered with a small amount of alcohol and aged for 1 day, and then replaced with alcohol 3 times for 12 hours each time.

[0039] SiO 2 Put the wet gel into a supercritical drying equ...

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Abstract

The invention relates to a heat-resisting silica aerogel material and a preparation method thereof. SiO2 sol is prepared by adopting a sol-gel method, modified liquid is innovatively led to a supercritical drying process by ageing and solvent replacement through adopting a supercritical modification process, so as to obtain bulk aerogel which is high in mechanical strength and easy to process, and then the SiO2 aerogel of which linear contraction just is 5%, and the specific surface area can be up to 530m<2>/g after high-temperature treatment at 1000 DEG C can be obtained by high-temperature pretreatment at 800 DEG C and gas-phase modification of hexamethyldisilazane. By adopting the synthetic method, application of the SiO2 aerogel in high-temperature fields such as high-temperature catalysis, a catalyst carrier and high-temperature heat preservation and insulation is greatly facilitated.

Description

technical field [0001] The invention belongs to the technical field of preparation of airgel materials, and relates to a preparation method of a high-temperature-resistant silica airgel material. Background technique [0002] As a nanoporous material with high porosity (>90%), high specific surface area, and low density, SiO 2 Aerogels have been successfully applied in Cherenkov detectors, super heat insulating materials, catalyst supports, etc. With the development of catalysis and thermal insulation fields, the demand for high temperature resistant aerogels is becoming more and more urgent. For example when dealing with gaseous emissions or catalytic combustion, certain catalytic reactions are carried out at temperatures above 800°C. Another example is that when a supersonic vehicle travels through the atmosphere, due to the severe friction with the air, the heat-resistant temperature of the outer heat insulation material needs to reach 1000°C or even higher. Therefo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/16
Inventor 刘光武徐少洪何丹农
Owner SHANGHAI NAT ENG RES CENT FORNANOTECH
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