SiO2 aerogel and preparation method thereof

A technology of airgel and gel method, applied in the field of airgel, can solve problems such as hole collapse, airgel skeleton shrinkage and cracking, and achieve the effect of preventing collapse

Inactive Publication Date: 2018-05-18
TIANJIN MROGAN KUNDOM HI TECH DEV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The first object of the present invention is to provide a SiO 2 A preparation method of airgel to alleviate the technical problems that existing preparation methods easily lead to airgel skeleton shrinkage and cracking and hole collapse

Method used

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  • SiO2 aerogel and preparation method thereof

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preparation example Construction

[0021] One aspect of the present invention provides a SiO 2 The preparation method of airgel, utilizes the SiO that adopts sol-gel method to prepare by supercritical drying method 2 The wet gel was dried to obtain SiO 2 Airgel, the supercritical drying includes: under an inert atmosphere and within the pressure range of 2-7MPa, gradually increase the pressure to perform gradient segmental drying, and then increase the pressure to 11-12MPa for constant pressure drying, and the drying temperature is 270 -280°C.

[0022] SiO provided by the present invention 2 In the preparation method of aerogel, the SiO 2 The wet gel is dried to make the SiO 2 The ethanol in the wet gel can be fully evaporated to prevent SiO 2 Wet gels crack during drying. This drying treatment method will not damage SiO 2 The three-dimensional network structure of the airgel to prevent the collapse of the pores in the airgel. SiO with a complete network structure can be obtained by using the dry treatm...

Embodiment 1

[0040] This example is a SiO 2 The preparation method of airgel, comprises the following steps:

[0041] Step a) Preparation of SiO by sol-gel method 2 Wet gel: hydrochloric acid is added dropwise in water glass for catalytic reaction, and after the reaction is completed, SiO is obtained by aging, alcohol replacement and modification. 2 wet gel;

[0042] Among them, the weight ratio of sodium silicate to water in water glass is 1:3, the concentration of hydrochloric acid is 0.03mol / L, the aging temperature is 50°C, and the aging time is 24h;

[0043] Step b) using the supercritical drying method to prepare the SiO obtained by the sol-gel method 2 The wet gel was dried to obtain SiO 2 Airgel, the supercritical drying method in this embodiment is: first dry under the pressure of 2.5MPa for 40min, then dry under the pressure of 3.5MPa for 50min, then dry under the pressure of 4.5MPa for 50min, and then dry it under the pressure of 5.5MPa Dry under the pressure of MPa for 60m...

Embodiment 2

[0046]This example is a SiO 2 The preparation method of airgel, comprises the following steps:

[0047] Step a) Preparation of SiO by sol-gel method 2 Wet gel: hydrochloric acid is added dropwise in water glass for catalytic reaction, and after the reaction is completed, SiO is obtained by aging, alcohol replacement and modification. 2 wet gel;

[0048] Among them, the weight ratio of sodium silicate to water in water glass is 1:4, the concentration of hydrochloric acid is 0.04mol / L, the aging temperature is 55°C, and the aging time is 22h;

[0049] Step b) using the supercritical drying method to prepare the SiO obtained by the sol-gel method 2 The wet gel was dried to obtain SiO 2 Airgel, the supercritical drying method in this embodiment is: first dry under the pressure of 3.5MPa for 50min, then dry under the pressure of 5MPa for 60min, and then dry under the pressure of 6MPa for 40min to complete the gradient segmental drying; After the gradient drying is completed, d...

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Abstract

The invention provides SiO2 aerogel and a preparation method thereof and relates to the field of aerogel. The preparation method of the SiO2 aerogel comprises the step: drying wet SiO2 gel prepared byadopting a sol-gel method by utilizing a supercritical drying method, thereby obtaining the SiO2 aerogel. The supercritical drying comprises sub-steps: gradually boosting the pressure in an inert atmosphere and in a pressure range of 2-7MPa so as to perform gradient stage drying, raising the pressure to 11-12MPa, and performing constant pressure drying, wherein the constant pressure drying temperature is 270-280 DEG C. According to the preparation method, the technical problem that aerogel skeleton shrinkage crack and hole collapse is easily caused in the conventional preparation method can be solved, and the aims of improving the porosity and preventing the aerogel from cracking are achieved.

Description

technical field [0001] The invention relates to the field of airgel, in particular to a SiO 2 Aerogels and methods of making them. Background technique [0002] Silica airgel is a nanoporous lightweight inorganic material with a porosity as high as 80-99.8%, a typical size of pores of 1-100nm, and a specific surface area of ​​200-1000m 2 / g, while the density can be as low as 3kg / m 3 , the thermal conductivity at room temperature can be as low as 0.012W / (mk), which is the best thermal insulation performance among solid materials at present. At the same time, silica airgel also has good temperature resistance, which can withstand high temperatures of up to 600-900 ° C, and the low temperature range is close to absolute zero. It is an excellent thermal insulation material. [0003] At present, silica airgel is mainly prepared by the sol-gel method. In the later drying process, due to the drying of the wet gel, problems such as skeleton shrinkage and cracking and hole collap...

Claims

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Application Information

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IPC IPC(8): C01B33/158
CPCC01B33/1585C01P2006/32C01P2006/90
Inventor 王振宇孙晔崔伟腾胡菊李振声王世伟
Owner TIANJIN MROGAN KUNDOM HI TECH DEV
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