A method for quickly preparing airgel by accelerated solvent extraction at atmospheric pressure

A technology to accelerate solvents and aerogels, applied in chemical instruments and methods, inorganic chemistry, silicon compounds, etc., can solve the problems of low quality airgel powder, limited application fields, and prone to salting out, etc., to reduce production risks , Simplify the process and shorten the production cycle

Active Publication Date: 2020-05-19
浙江岩谷科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the existence of ions, this method greatly slows down the speed of surface silanization treatment. It is only suitable for the preparation of airgel powder, and the application field is very limited. Due to the incomplete removal of ions, there are still a large amount of residues in the gel powder. Ions, salting-out phenomenon is very easy to occur during storage, resulting in SiO 2 Airgel powder is of low quality and poor performance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Sodium silicate and water are mixed at a volume ratio of 1:3 at room temperature, added to 20% sulfuric acid solution, and the pH reaches 5.0, and a gel is formed after 30 seconds. After the gel is crushed, put it into the extraction kettle, pump in alcohol with a volume concentration of 10% at 100°C, and control the absolute pressure of the extraction kettle to not be lower than 0.25MPa. After the alcohol is immersed in the gel, pump in alcohol with a volume concentration of 90%. Alcohol, at the same time, pump out the low-concentration alcohol in the reactor at the same rate, keep the alcohol level in the extraction tank unchanged, and gradually increase the alcohol concentration in the reactor from 10% to 80% within 25 minutes; then pump into 110°C hexamethyldisilazane alcohol aqueous solution (volume fractions of hexamethyldisilazane, alcohol, and water were 15%, 80%, and 5% respectively) for further accelerated solvent extraction for 30 minutes, and maintained The ...

Embodiment 2

[0045] Mix potassium silicate and water at a volume ratio of 1:2 at room temperature, add it to 8% acetic acid solution, make the pH reach 5.5, pour the mixture into a mold with a 10mm thick glass fiber felt, and form after 2 minutes gel. Put the composite material into the extraction kettle, pump in alcohol with a mass concentration of 20% at 120°C, and control the absolute pressure of the extraction kettle to not be lower than 0.45MPa. After the composite material is immersed in the alcohol, pump in alcohol with a mass concentration of 92%. At the same time, the low-concentration alcohol in the extraction kettle is pumped out at the same rate, so that the alcohol mass concentration in the extraction kettle is gradually increased from 20% to 90% within 40 minutes, and then pumped in at 120°C with a volume fraction of 5% hexamethyldisilazide Alkanes alcohol solution to further accelerate solvent extraction and surface hydrophobic treatment, the time is 50min, the volume fracti...

Embodiment 3

[0047] Mix sodium silicate and water at a volume ratio of 1:4 at room temperature, add it to 10% sulfuric acid solution, and make the pH reach 4.8, pour the mixture into a mold with a 6mm thick glass fiber felt, and form after 2 minutes gel. Put the composite material into the extraction kettle, pump in acetone at 105°C and water at 105°C at the same time, control the ratio of the two through a flowmeter, make the volume concentration of acetone reach 20%, control the absolute pressure of the extraction kettle not less than 0.35MPa, acetone After immersing the composite material in the aqueous solution, adjust the amount of acetone and water pumped in so that the volume concentration of acetone gradually increases from 20% to 100% within 30 minutes. The volume concentration of acetone is gradually increased from 5% to 90% within 40 minutes, the pump is stopped and maintained for 8 minutes, and then acetone and dimethyldimethoxysilane at 105 °C are pumped in at the same time, a...

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Abstract

The invention discloses a method for rapidly preparing aerogel by accelerating solvent extraction in a normal pressure. The method comprises the following steps: (1) enabling a quantitative inorganicsilicon source to be mixed with water and diluting, adding quantitative acid, forming saliferous silica sol, and forming gel after a period of time; (2) performing accelerated solvent extraction on the gel obtained in the step (1) by using organic solvent water solution of which concentration is increased along with time; (3) performing the accelerated solvent extraction on the gel obtained in thestep (2) by mixed liquid of a water-containing organic solvent and an organosilicon compound; and (4) drying the gel obtained in the step (2) in the normal pressure. The provided method for preparingthe aerogel is simple in process, short in production period, and less in energy consumption. An aerogel product of the method has the characteristics of complete structure, low heat conductivity coefficient, and good mechanical strength.

Description

technical field [0001] The invention relates to the technical field of manufacturing nanoporous airgel materials, in particular to a method for rapidly preparing airgel by accelerating solvent extraction. Background technique [0002] SiO 2 Airgel is currently one of the most widely concerned thermal insulation materials, which is composed of highly cross-linked SiO 2 The porous material prepared by the gel through a special drying process has a three-dimensional network structure, and its skeleton and pore structure are at the nanometer level. The unique structure makes SiO 2 Airgel material has extremely low thermal conductivity, can effectively inhibit heat conduction and heat convection, and is considered to be the solid material with the best thermal insulation performance. [0003] Due to its great application potential, researchers from all over the world have invested in the development of various SiO2 2 Airgel preparation methods, the silicon sources used are al...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/158
CPCC01B33/1585
Inventor 闫方闵阳
Owner 浙江岩谷科技有限公司
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