Preparation method of silicon dioxide aerogel material

A silica and aerogel technology, applied in the field of chemical materials, can solve the problems of difficult reaction control, violent reaction of silicon tetrachloride, unable to obtain stable products, etc., to achieve the effect of improving performance and stable and controllable process.

Inactive Publication Date: 2018-06-12
UNIV OF SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, silicon tetrachloride and water react violently, and a large amount of heat will be emitted in an instant. The reaction is difficult to control and a stable product cannot be obtained.

Method used

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Examples

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preparation example Construction

[0028] The invention provides a kind of preparation method of silica airgel material, comprises the following steps:

[0029] a1), silicon tetrachloride and alcohol are mixed to carry out alcoholysis reaction, obtain reaction solution;

[0030] b1), mixing and reacting the reaction solution with water to obtain silica sol;

[0031] c1), sequentially performing gelation and aging on the silica sol to obtain a wet gel;

[0032] d1), mixing the wet gel with a hydrophobic modifier to perform hydrophobic modification to obtain a hydrophobic wet gel;

[0033] e1), drying the hydrophobic wet gel to obtain silica airgel.

[0034] In the present invention, first, silicon tetrachloride and alcohol are mixed for alcoholysis reaction. Wherein, the alcohol includes but not limited to one or more of methanol, ethanol and propanol, preferably ethanol; the volume ratio of the silicon tetrachloride and the alcohol is preferably 1:(2~4), specifically can be 1:2, 1:2.5, 1:3, 1:3.5 or 1:4; th...

Embodiment 1

[0057] This embodiment provides a method for preparing silica airgel powder at normal pressure using silicon tetrachloride as a silicon source, which includes the following steps:

[0058] (1) First, add 20ml of silicon tetrachloride into 60ml of absolute ethanol, and carry out alcoholysis reaction in an ice-water bath at 0°C for 10 minutes.

[0059] (2) Next, react the solution obtained after the alcoholysis reaction with 60ml of water, and react in an ice-water bath at 0°C for 20 minutes to obtain a silica sol; in this step, the alcoholysis solution reacts gently with water, and no partial overheating of the reaction occurs On the other hand, when precipitation occurs, the obtained silica sol is stable and uniform.

[0060] (3) Then, the silica sol was left to stand for gelation, and after the gel was formed, it was aged at 45° C. for 4 hours to obtain a wet gel.

[0061] (4) Next, take 50 ml of wet gel and add 100 ml of hexamethyldisiloxane, and stir in a water bath at 45°...

Embodiment 2

[0066] The present embodiment provides a kind of method that silicon tetrachloride is silicon source atmospheric pressure preparation silica airgel felt pad, and it comprises the following steps:

[0067] (1) First, add 20ml of silicon tetrachloride into 60ml of absolute ethanol, and carry out alcoholysis reaction in an ice-water bath at 0°C for 10 minutes.

[0068] (2) Next, react the solution obtained after the pre-reaction with 60ml of water, and react in an ice-water bath at 0°C for 20 minutes to obtain a silica sol; in this step, the alcoholysis solution reacts gently with water, and no partial overheating of the reaction occurs On the other hand, when precipitation occurs, the obtained silica sol is stable and uniform.

[0069] (3) Then, pour the sol into a mold with a size of 10cm x 10cm and a 10mm thick glass fiber felt pad, so that the sol completely infiltrates the felt pad in the mold and microwaves the gel; After accelerated aging for 1 h, a felt pad containing we...

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Abstract

The invention belongs to the field of chemical materials, and particularly relates to a preparation method of a silicon dioxide aerogel material. The method comprises the following steps: mixing silicon tetrachloride with alcohol and carrying out alcoholysis reaction to obtain reaction liquid; carrying out mixing reaction on the reaction liquid and water to obtain silica sol; successively carryingout gelation and ageing on the silica sol to obtain wet gel; mixing the wet gel with a hydrophobic modifier and carrying out hydrophobic modification to obtain hydrophobic wet gel; and drying the hydrophobic wet gel to obtain silicon dioxide aerogel. After the silica soil is obtained, a felt pad is soaked with the silica soil to prepare a silicon dioxide aerogel felt pad. The method is stable andcontrollable when the silica sol is prepared, the problems that precipitates are generated due to local over heating in a reacting process due to the fact that silicon tetrachloride directly reacts with water, and uniform and stable silica soil cannot be formed are solved, and the performance of the finally prepared silicon dioxide aerogel material is improved.

Description

technical field [0001] The invention belongs to the field of chemical materials, in particular to a method for preparing a silica airgel material. Background technique [0002] Silica airgel is a lightweight nanoporous material with high porosity, large specific surface area, low density and low thermal conductivity, these characteristics make silica airgel materials in thermal, acoustic, optical, micro Electronics and particle detection have very broad application potential. Although silica airgel has excellent performance, its preparation cost is too high, which greatly limits its popularization and application. [0003] At present, the preparation of silica airgel mostly adopts supercritical drying process. However, the supercritical process equipment is complicated, the cost is high, and there are certain risks. Therefore, the atmospheric pressure drying process has gradually become a hot spot of everyone's attention. Atmospheric pressure drying technology to prepare s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/158D06M11/79
CPCC01B33/1585C01P2006/11C01P2006/32D06M11/79D06M2200/12
Inventor 龚伦伦程旭东张和平周婷
Owner UNIV OF SCI & TECH OF CHINA
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