Method for preparing super-hydrophobic silica aerogel at normal pressure

A silicon dioxide and super-hydrophobic technology, applied in the direction of silicon dioxide, silicon oxide, etc., can solve the problems of restricting silicon dioxide aerogel, high equipment material requirements, restricting the popularization and use, etc., to achieve a simple and dangerous process. Low-response, parameter-adjustable effects

Inactive Publication Date: 2010-09-29
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the supercritical drying process is complicated, the requirements for equipment materials are high, and the potential dan

Method used

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  • Method for preparing super-hydrophobic silica aerogel at normal pressure
  • Method for preparing super-hydrophobic silica aerogel at normal pressure
  • Method for preparing super-hydrophobic silica aerogel at normal pressure

Examples

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example 1

[0020] Prepare a sodium silicate aqueous solution with a mass ratio of 23%, then adjust the pH value to 1 with concentrated hydrochloric acid, and obtain a gel after standing in an environment of 50°C for 30 minutes, and then use deionized water, ethanol, n-hexane and volume ratio in sequence The mixed solutions of 20% n-hexane and trimethylchlorosilane were treated for 24 hours respectively, and finally dried at 150° C. to obtain silica airgel. The specific surface area of ​​the resulting silica airgel is 543m 2 / g, the pore volume is 3.43cm 3 g -1 , the internal pore diameter is 25.3nm.

example 2

[0022] Take 3.03g of sodium silicate aqueous solution with a mass ratio of 23%, adjust the pH value to 1 with concentrated hydrochloric acid, then add 2.08g of deionized water, and obtain a gel after standing at 50°C for 3 hours, and then use deionized A mixed solution of ionic water, ethanol, n-hexane and 20% by volume of n-hexane and trimethylchlorosilane was treated for 24 hours respectively, and finally dried at 150° C. to obtain a silica airgel. The specific surface area of ​​the resulting silica airgel is 572m 2 / g, the pore volume is 2.03cm 3 g -1 , the internal pore diameter is 14.1nm.

example 3

[0024] Take 3.03g of sodium silicate aqueous solution with a mass ratio of 23%, adjust the pH value to 1 with concentrated hydrochloric acid, then add 4.16g of deionized water, and obtain a gel after standing at 15°C for 40 hours, and then use A mixed solution of ionic water, ethanol, n-hexane and 20% by volume of n-hexane and trimethylchlorosilane was treated for 24 hours respectively, and finally dried at 150° C. to obtain a silica airgel. The specific surface area of ​​the silica airgel is 582m 2 / g, the pore volume is 2.5cm 3 g -1 , the internal pore diameter is 17.3nm.

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Abstract

The invention discloses a method for preparing super-hydrophobic silica aerogel at the normal pressure by taking an inorganic silicon source or an organic silicon source as a raw material. The method comprises the following steps: taking the inorganic silicon source or the organic silicon source as the raw material, then mixing the raw material with a solvent and a catalyst, and obtaining wet gel through a process of sol-gel, and then carrying out ageing, solvent replacement, surface modification and ambient pressure drying on the obtained wet gel to obtain the silica aerogel with low-density, high specific table and super hydrophobicity. The invention realizes the ambient pressure drying of the wet gel, avoids the equipment investment when the conventional supercritical drying is adopted, greatly improves the safety of the production, has simple operation, good properties and controllability of the products, and is suitable for large-scale production.

Description

technical field [0001] The invention belongs to the field of chemical material preparation and relates to a method for preparing superhydrophobic silica airgel under normal pressure. Background technique [0002] Silica airgel is a lightweight porous material with continuous random pore structure. Its unique structure makes it have many excellent properties, especially its low density, low thermal conductivity, and its ability to operate under visible light. The properties such as high transparency in the area make it have great application prospects in the field of thermal insulation. [0003] Fricke et al. studied the infrared thermal radiation conduction of airgel, and they found that the thermal conductivity of the double-layer thermal insulation window prepared by SiO2 airgel is lower than 0.002W m -1 ·K -1 . Jensen et al. filled 15mm of SiO in the middle of the glass 2 Airgel makes the heat loss coefficient of the center less than 0.7W·m 2 ·K -1 , the light trans...

Claims

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Application Information

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IPC IPC(8): C01B33/16
Inventor 李文翠孙涛
Owner DALIAN UNIV OF TECH
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