Preparation method for hydrophobic large-size bulk nanometer porous SiO2 aerogel

An airgel and wet gel technology, applied in chemical instruments and methods, inorganic chemistry, non-metallic elements, etc., can solve the problems of reducing the performance of airgel, restricting the extensiveness, and unsatisfactory thermal insulation effect, etc., and achieving easy Recycling, cost reduction, good effect of surface treatment

Inactive Publication Date: 2012-09-12
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, at present, it is difficult to obtain SiO with good formability under the premise of reducing the preparation cost (using cheap silicon sources). 2 Airgel bulk, SiO 2 The

Method used

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  • Preparation method for hydrophobic large-size bulk nanometer porous SiO2 aerogel
  • Preparation method for hydrophobic large-size bulk nanometer porous SiO2 aerogel
  • Preparation method for hydrophobic large-size bulk nanometer porous SiO2 aerogel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] (1) 10ml of pure industrial grade water glass (the substance ratio of the solution: n (Na 2 O):n(SiO 2 )=1:3.1), add 40ml of deionized water to dilute, and at room temperature, the diluted solution is passed through an exchange column (diameter 2cm×height 50cm) filled with strong acid styrene cation exchange resin to remove sodium ions and other cations in water glass . The pH value of the treated solution was 3.0, and then 1 mol / L sodium hydroxide solution was added to adjust the pH value to 6.0;

[0054] (2) After stirring for 30 min, pour the silica sol into a polyethylene mold and let it stand to form a wet gel. Cover the surface of the wet gel with 10ml of deionized water, the volume is 1 / 5 of the wet gel, and let it age at room temperature for about 5 hours;

[0055] (3) Soak the wet gel in 100 ml of absolute ethanol for 24 hours, during which the ethanol is replaced at least twice, and the volume ratio of the wet gel to absolute ethanol is 1:2.

[0056] (4) T...

Embodiment 2

[0060] (1) 5ml pure water glass (the substance ratio of the solution: n (Na 2 O):n(SiO 2 ) = 1: 3.1), add 35ml of deionized water to dilute, and at room temperature, pass the diluted solution through an exchange column (diameter 2cm×height 50cm) filled with strong acid styrene cation exchange resin to remove sodium ions and other cations in the water glass . The pH value of the treated solution was 2.5, and 2 mol / L ammonia solution was added to adjust the pH value to 8.0.

[0061] (2) After stirring for 2 hours, pour the silica sol into a glass container and let it stand to form a wet gel. The surface of the wet gel was covered with 5 ml of deionized water and allowed to age at room temperature for about 7 hours.

[0062] (3) Soak the wet gel in 120 ml of methanol for 24 hours, during which the methanol is replaced at least three times, and the volume ratio of the wet gel to methanol is 1:3.

[0063] (4) Then the SiO 2 The wet gel was immersed in a mixture of 17.5 ml of m...

Embodiment 3

[0067] (1) 5ml pure water glass (the substance ratio of the solution: n (Na 2 O):n(SiO 2 )=1:3.1), add 50ml of deionized water to dilute, and at room temperature, pass the diluted solution through an exchange column (diameter 2cm×height 50cm) filled with strong acid styrene cation exchange resin to remove sodium ions and other cations in water glass . The pH value of the treated solution was 2.0, and then 5 mol / L potassium hydroxide solution was added to adjust the pH value to 4.0,

[0068] (2) After stirring for 6 hours, pour the silica sol into a glass container and let it stand to form a wet gel. The surface of the wet gel was covered with 7 ml of deionized water and allowed to age at room temperature for about 8 hours.

[0069] (3) The wet gel was soaked in 55 ml of acetone for 48 hours, during which the acetone was replaced at least 4 times, and the volume ratio of the wet gel to acetone was 1:1.

[0070] (4) Then the SiO 2 The wet gel was immersed in a mixture of 10...

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Abstract

The invention belongs to the technical field of preparation of inorganic nanometer porous materials, and relates to a preparation method for SiO2 aerogel. The preparation method includes following steps: (1) preparation of silica sol; (2) formation and ageing of wet gel; (3) replacement of solvent of the wet gel; (4) surface modification and replacement of the solvent of the wet gel; and (5) constant-pressure drying. The preparation method is simple in process, cheap in price and suitable for large-scale production and application. Tests show that prepared hydrophobic large-size bulk nanometer porous SiO2 aerogel has high specific surface area, low density and low heat conductivity, and has a stable hydrophobic property at temperature ranging from room temperature to 400 DEG C. Accordingly, an absorption property and a heat insulation property of the SiO2 aerogel prepared by the preparation method are excellent, and the SiO2 aerogel has an excellent application prospect in the fields of heat insulation and energy conservation.

Description

technical field [0001] The invention belongs to the technical field of preparation of inorganic nano-porous materials, and relates to a kind of nano-porous SiO 2 Preparation method of aerogel. Background technique [0002] SiO 2 Aerogel is a material with a unique nanoporous structure in which an interwoven three-dimensional network is distributed. This special structure makes it have high porosity (can be maintained at 85-95%, up to 99.8%), small pore size (1 ~ 100nm), high specific surface area (1000m 2 / g), low density (0.03-0.2g / cm 3 ), small refractive index (1.01-11), low speed of sound (100m / s), ultra-low thermal conductivity 0.015W / (m·K) and other properties. Many excellent properties make it used in many fields such as drug delivery systems, solar collectors, catalysis, adsorption, and NASA's Cherkiv radiation detectors to capture high-speed particles in space. [0003] SiO 2 The preparation of aerogels is usually carried out by supercritical drying, and the m...

Claims

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Application Information

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IPC IPC(8): C01B33/158
Inventor 倪星元刘光武周斌沈军张志华虞秋捷
Owner TONGJI UNIV
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