Modification method for silicon dioxide aerogel

A technology of silica and airgel, applied in chemical instruments and methods, inorganic chemistry, silicon compounds, etc.

Inactive Publication Date: 2008-10-01
BEIJING HUACONG TRADE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Siloxanes need to add HCl as a ca

Method used

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  • Modification method for silicon dioxide aerogel
  • Modification method for silicon dioxide aerogel
  • Modification method for silicon dioxide aerogel

Examples

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Example Embodiment

[0016] According to a specific embodiment of the present invention, the specific steps of dehydration modification are as follows:

[0017] 1. Filter or press-filter the synthesized or purchased silica wet gel into a wet cake with 80-95% (mass) water content.

[0018] 2. Immerse the wet cake in the C4-C10 aliphatic alcohol, and the volume ratio of the amount of alcohol added to the water content in the wet cake is: (0.1-10):1. Stir the multiphase system evenly.

[0019] 3. Continuously stir and heat the multi-phase system. When the azeotropic temperature of water and alcohol is reached, water and alcohol are azeotropically distilled out in a constant volume ratio. The temperature of the system remains unchanged, and the liquid level is always higher than the solid phase during heating. If it is not enough, continue to add alcohol. After condensing the obtained steam and standing for stratification, the oil phase can be recycled.

[0020] 4. When the temperature of the system rises...

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Abstract

The invention relates to a method for modifying silicon dioxide aerogel. The method of the invention is characterized in that the nature of the azeotropy of C4 to C10 aliphatic alcohols and water under the constant temperature is utilized for removing free water in the silicon dioxide wet gel; the esterification reaction of alcohol and hydroxyl on the surface of silicon dioxide is utilized for the surface finishing and modification of the silicon dioxide aerogel so as to obtain water repellent products; wherein, the mass ratio of the silicon dioxide, the water, the a lcohol and a catalyst is 1: (8.0 to 9.5): (10 to 20): (0.01 to 0.05) and the catalyst is alkyl-sulfuric acid, alkyl sulfate or alkyl sulphate ion, aryl sulfonic acid, aryl-sulphonate or aryl-sulphonate ion. The invention also relates to the silicon dioxide aerogel obtained by the method and the surface of the silicon dioxide aerogel is dehydrated and contains aliphatic groups.

Description

technical field [0001] The invention belongs to the technical field of surface modification of inorganic powder materials, and in particular relates to a drying dehydration and hydrophobic modification method of silica wet gel. Background technique [0002] SiO 2 Airgel is a lightweight nanoporous amorphous solid material, which has the characteristics of low density, high specific surface area, large pore volume, adjustable refractive index, low thermal conductivity, large acoustic impedance, and good insulation. It is widely used in Optics, thermals, acoustics, electricity and other fields. However, the polysiloxane in the interior of the silica and the active silanol on the outer surface absorb water extremely, making it hydrophilic and difficult to wet and disperse in the organic phase. Moreover, due to the presence of hydroxyl groups on the surface, the surface energy is relatively high Large aggregates tend to coagulate, thus affecting the application performance of ...

Claims

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Application Information

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IPC IPC(8): C01B33/158C01B33/157
Inventor 张连华
Owner BEIJING HUACONG TRADE
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