Preparation method of blocky silicon-carbon composite aerogel

A composite technology of airgel and carbon, which is applied in chemical instruments and methods, catalyst carriers, physical/chemical process catalysts, etc., can solve the problems of low strength, low airgel density, airgel fragmentation, etc., and achieve durability Good high temperature performance, perfect network structure, good molding performance

Active Publication Date: 2012-02-08
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, due to the low density and low strength of the aerogel, the prepared airgel product is easily broken, and it is impossible to obtain a block aerogel with a complete shape; The collapse of the pore structure; the heat treatment process will destroy the pore structure of the airgel, and eventually lead to the fragmentation of the airgel. Application of thermal insulation materials

Method used

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  • Preparation method of blocky silicon-carbon composite aerogel
  • Preparation method of blocky silicon-carbon composite aerogel
  • Preparation method of blocky silicon-carbon composite aerogel

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0025] (1) Mix tetraethyl orthosilicate, nitric acid, deionized water, and absolute ethanol in a molar ratio of 1:0.1:4:60 to form solution A, and pre-hydrolyze at 35°C for 40 minutes;

[0026] (2) Mix resorcinol, formaldehyde, potassium hydroxide, and absolute ethanol in a molar ratio of 1:2:300:1 to form solution B, and pre-react at 50° C. for 60 minutes.

[0027] (3) According to the molar ratio of tetraethyl orthosilicate and resorcinol being 1:1, solution A and solution B were mixed under stirring, and ammonia water was added to adjust the pH value to 8.5.

[0028] (4) Place the solution obtained in step (3) in a 40°C oven for 300 minutes to obtain a wet gel. The wet gel is aged in a 60°C water bath for 10 days, and then the wet gel is solvent-substituted with methanol. Methanol was replaced once every 12 hours, a total of 4 replacements, and CO was carried out after the solvent replacement was completed. 2 Supercritical drying, at 10MPa and 25°C, replace with a gas rele...

example 2

[0032] (1) Mix tetraethyl orthosilicate, acetic acid, deionized water, and absolute ethanol in a molar ratio of 1:0.1:6:43 to form solution A, and pre-hydrolyze at 25°C for 35 minutes;

[0033] (2) Mix resorcinol, formaldehyde, sodium hydroxide, and absolute ethanol in a molar ratio of 1:2:200:0.5 to prepare solution B, and pre-react at 60° C. for 35 minutes.

[0034] (3) According to the molar ratio of tetraethyl orthosilicate and resorcinol being 1:1, solution A and solution B were mixed under stirring, and ammonia water was added to adjust the pH value to 9.2.

[0035] (4) Place the solution obtained in step (3) in a 50°C oven for constant temperature reaction for 25 minutes to obtain a wet gel. The wet gel is aged in a 60°C water bath for 10 days, and then acetone is used for solvent replacement of the wet gel. Acetone was replaced every 6 hours, a total of 4 replacements, and CO was carried out after the solvent replacement was completed. 2 Supercritical drying, replace ...

example 3

[0039] (1) Mix tetraethyl orthosilicate, hydrochloric acid, deionized water, and absolute ethanol in a molar ratio of 1:0.03:8:38 to form solution A, and pre-hydrolyze at 35°C for 30 minutes;

[0040] (2) Mix resorcinol, formaldehyde, sodium carbonate, and absolute ethanol in a molar ratio of 1:2:200:0.5 to form solution B, and pre-react at 70°C for 20 minutes.

[0041](3) According to the molar ratio of tetraethyl orthosilicate and resorcinol being 1:1, solution A and solution B were mixed under stirring, and then ammonia water was added to adjust the pH value to 9.

[0042] (4) Place the solution obtained in step (3) in a 30°C oven for constant temperature reaction for 50 minutes to obtain a wet gel. The wet gel is aged in a 50°C water bath for 15 days, and then the wet gel is solvent-substituted with ethanol. Ethanol was replaced once every 24 hours, a total of 5 replacements, and CO was carried out after the solvent replacement was completed. 2 Supercritical drying, at 10...

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Abstract

The invention provides a preparation method of blocky silicon-carbon composite aerogel. The preparation method comprises the steps of: by taking resorcinol, formaldehyde and tetraethyl orthosilicate as reactants, respectively preparing silica sol and organic sol, mixing the silica sol and the organic sol, then reacting at constant temperature to obtain wet gel, performing low-temperature carbon dioxide supercritical drying and high-heat treatment processes on the wet gel to obtain the blocky silicon-carbon composite aerogel. The blocky silicon-carbon composite aerogel prepared by adopting thepreparation method provided by the invention has the characteristics of high strength, large specific surface area, low density and thermostability, can be used at the temperature as high as more than 1000 DEG C, and is beneficial to overcoming of the defects of low strength, difficult in forming and poor thermostability of the aerogel.

Description

technical field [0001] The invention belongs to the technical field of silicon-carbon composite airgel preparation, and relates to a synthesis method for forming a network structure in which silicon dioxide and RF organic gel skeleton structures are interwoven in a sol-gel process, especially in combination with carbon dioxide A method for preparing bulk silicon-carbon composite airgel by critical drying technology and high temperature heat treatment process. Background technique [0002] Airgel is a lightweight solid material with a nanoporous network structure. It has structural characteristics such as low density, high specific surface area, and high porosity. It has broad application prospects in adsorption, catalysis, and impedance coupling, especially in In terms of heat insulation, its structural characteristics make it have extremely low thermal conductivity, which has obvious advantages compared with traditional heat insulation materials. People call this airgel mat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J32/00B01J21/18C04B30/00
Inventor 沈晓冬孔勇崔升仲亚
Owner NANJING UNIV OF TECH
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