Magnetic silica airgel and its preparation method by normal pressure drying

An atmospheric drying and aerogel technology, applied in the direction of silicon dioxide, silicon oxide, etc., can solve the problems of difficult industrial production, cumbersome operation, long preparation period, etc., and achieve the effect of improving stability and excellent magnetic properties.

Active Publication Date: 2017-10-31
苏州同玄新材料有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since atmospheric pressure drying requires multiple gel channel solvent exchanges and surface hydrophobic treatment, the preparation cycle is long and the operation is cumbersome, it is difficult to realize industrial production
[0004] On the other hand, for SiO 2 The research on the functional modification of airgel is also limited to the academic field, how to realize the industrial production of functionalized SiO 2 Aerogels, especially drying at atmospheric pressure to produce functionalized SiO 2 Aerogels, still an open problem

Method used

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  • Magnetic silica airgel and its preparation method by normal pressure drying
  • Magnetic silica airgel and its preparation method by normal pressure drying
  • Magnetic silica airgel and its preparation method by normal pressure drying

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preparation example Construction

[0046] A kind of magnetic SiO of the present invention 2 The preparation method of airgel comprises the steps:

[0047] (1) Partially hydrolyze orthosilicate to form various polysiloxanes;

[0048] (2) Mix the polysiloxane with magnetic nanoparticles, alcohol or ketone, and alkali catalyst evenly to form alcohol gel or ketone gel;

[0049] (3) After crushing the alcohol gel or ketone gel into powder or granular form, mix and stir with liquid alkane or fluoroalkane to replace the alcohol or ketone in the alcohol gel or ketone gel, thereby Obtain an alkane gel;

[0050] (4) mixing and stirring the alkane gel with a mixed solution of a hydrophobic agent and a liquid alkane to obtain a hydrophobic alkane gel;

[0051] (5) Dry the hydrophobic alkane gel under normal pressure to obtain magnetic SiO 2 airgel.

[0052] Wherein, in a more specific embodiment, the magnetic SiO 2 Airgel preparation methods may include:

[0053] (1) Mix and stir orthosilicate, hydrolysis catalyst, ...

Embodiment 1

[0076] (1) Preparation of CS silicone oil: 1 mole of methyl orthosilicate, 1.3 moles of dilute acid solution (10 -3 mol / L), ethanol (150ml) mixed, refluxed for later use after 8 hours.

[0077] (2) Magnetic SiO 2 Synthesis of composite gel: take 10 parts of CS silicone oil, 12 parts of ethanol and 1wt% Fe 3 o 4 The magnetic nanoparticles were placed in a stirring tank, and 1 ml of ammonia water was added dropwise under stirring at a stirring speed of 150 rpm, and an alcohol gel was formed after stirring for 5 minutes.

[0078] (3) Solvent replacement and hydrophobization treatment of gel particles: After crushing the alcohol gel, add 100ml of n-hexane, stir for 4 hours, filter, then put the gel particles in 100ml of n-hexane, and slowly add 8ml of hexamethyl di Silamine, stirred for 2 hours, and filtered to obtain surface hydrophobized modified alkane gel particles.

[0079] (4) Drying of wet gel particles: the surface hydrophobized modified gel particles are dried in a bl...

Embodiment 2

[0081](1) Preparation of CS silicone oil: 1 mole of methyl orthosilicate, 1.5 mole of dilute acid solution (concentration 10 -2 mol / L), ethanol (80ml) mixed, refluxed after 16 hours for subsequent use.

[0082] (2) Magnetic SiO 2 Synthesis of composite gel: Take 10 parts of CS silicone oil, 20 parts of ethanol, and 1 wt% of FeN magnetic nanoparticles, add 1.50 ml of ammonia water dropwise under stirring at 800 rpm, and form alcohol gel after stirring for 5 minutes.

[0083] (3) Solvent replacement and hydrophobization treatment of gel particles: crush the alcohol gel, add 150ml of n-hexane, stir for 4 hours, filter, then put the gel particles in 150ml of n-hexane, and slowly add 10ml of hexamethyl di Silamine, stirred for 2 hours, and filtered to obtain surface hydrophobized modified alkane gel particles.

[0084] (4) Drying of wet gel particles: the surface hydrophobized modified gel particles are dried in a blast dryer, the temperature is controlled at 80°C, and magnetic S...

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Abstract

The present invention discloses a magnetic silica aerogel and a normal pressure dry preparation method therefor. The method comprises: taking tetraethyl orthosilicate as a raw material to prepare polyethoxydisiloxane as a silicon source; uniformly mixing the silicon source, magnetic nano-particles, alcohol and an alkali catalyst; forming a gel by stirring the mixture; carrying out aging; then crushing a wet gel; replacing the wet gel with low surface tension liquid alkoxy or fluoroalkane and modifying the wet gel with a hydrophobic agent; performing filtration or centrifugation at a normal pressure; and finally drying the gel to obtain various SiO2 aerogel particles with various magnetic properties. According to the present invention, continuous production of the magnetic SiO2 aerogel is achieved; the production period is short, the production cost is low, and the aerogel disclosed by the present invention is energy-saving and environmental-friendly. The obtained magnetic SiO2 aerogel is a nano porous structure and has restively ideal density, thermal conductivity, specific surface area etc., and is endowed with a magnetic function while satisfies heat insulation performance.

Description

technical field [0001] The invention relates to a method for preparing silica airgel, in particular to a method for preparing magnetic silica airgel by using normal pressure drying technology, and belongs to the technical field of nanoporous materials. Background technique [0002] Airgel is a highly porous nano-material, which is currently the lightest solid material with the best thermal insulation performance in the world. Since silica airgel has a high specific surface area (400-1500m 2 / g), high porosity (80-99.8%), low density (0.003-0.6g / cm 3 ) and low thermal conductivity (0.013~0.038W / mk), making silica aerogels widely used in high temperature resistant heat insulation materials, ultra-low density materials, acoustic impedance coupling materials, gas adsorption and filter materials, catalyst carrier materials, Drug carrier materials and other fields have very broad application prospects. Usually the method for preparing SiO2 airgel is supercritical drying, such a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/16
Inventor 张学同王锦
Owner 苏州同玄新材料有限公司
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