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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  • Abstract
  • Description
  • Claims
  • Application Information

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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 te

Method used

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  • SiO2 aerogel and preparation method thereof

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Example Embodiment

[0021] One aspect of the present invention provides a SiO 2 The method for preparing aerogels is to use the supercritical drying method to compare the SiO prepared by the sol-gel method 2 After the wet gel is dried, SiO is obtained 2 For aerogels, the supercritical drying includes: gradually increasing the pressure in a pressure range of 2-7MPa to perform gradient stepwise drying, and then increasing the pressure to 11-12MPa for constant pressure drying, and the drying temperature is 270 -280°C.

[0022] SiO provided by the invention 2 In the preparation method of aerogel, the SiO 2 The wet gel is dried to make SiO 2 The ethanol in the wet gel can fully evaporate to prevent SiO 2 The wet gel cracked during the drying process. This drying method will not damage SiO 2 The three-dimensional network structure of the aerogel prevents the pores in the aerogel from collapsing. The drying treatment method provided by the present invention can obtain SiO with a complete network structure ...

Example Embodiment

[0039] Example 1

[0040] This embodiment is a SiO 2 The preparation method of aerogel includes the following steps:

[0041] Step a) Prepare SiO by sol-gel method 2 Wet gel: Add hydrochloric acid dropwise to the water glass for catalytic reaction. After the reaction, aging, alcohol replacement and modification are performed to obtain SiO 2 Wet gel

[0042] Among them, the weight ratio of sodium silicate to water in the 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) Use the supercritical drying method to treat the SiO prepared by the sol-gel method 2 After the wet gel is dried, SiO is obtained 2 For aerogels, the supercritical drying method in this embodiment is: first dry at a pressure of 2.5 MPa for 40 minutes, then dry at a pressure of 3.5 MPa for 50 minutes, then dry at a pressure of 4.5 MPa for 50 minutes, and then at 5.5 Dry for 60 minutes at a pressure of MPa, and finally dry at...

Example Embodiment

[0045] Example 2

[0046] This embodiment is a SiO 2 The preparation method of aerogel includes the following steps:

[0047] Step a) Prepare SiO by sol-gel method 2 Wet gel: Add hydrochloric acid dropwise to the water glass for catalytic reaction. After the reaction, aging, alcohol replacement and modification are performed to obtain SiO 2 Wet gel

[0048] Among them, the weight ratio of sodium silicate to water in the 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) Use the supercritical drying method to treat the SiO prepared by the sol-gel method 2 After the wet gel is dried, SiO is obtained 2 For aerogels, the supercritical drying method in this embodiment is: first drying at a pressure of 3.5 MPa for 50 minutes, then drying at a pressure of 5 MPa for 60 minutes, and then drying at a pressure of 6 MPa for 40 minutes to complete the gradient stepwise drying; After the gradient drying...

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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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