Method for preparing silicon dioxide/graphene composite aerogel and composite aerogel obtained thereby

A graphene composite and silicon dioxide technology, applied in the field of airgel, can solve the problems of long steps, high cost, and insufficient heat insulation performance, so as to improve heat insulation performance, low high temperature thermal conductivity, and save equipment investment Effect

Active Publication Date: 2020-02-04
江苏和硅纳米科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are mainly two methods, one is to coat silica on the surface of graphene airgel, such as CN107117608B, CN108083262A, CN107235744A, the steps of this method are long, the cost is high, and graphene airgel needs to be prepared earlier; the other A kind of method is that graphene oxide and silicon source are compounded together in sol-gel, such as CN107032360B, CN107032360B, CN108218386A, CN107304052A, but the thermal insulation performance of the silicon dioxide / graphene composite airgel obtained at high temperature is not good enough

Method used

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  • Method for preparing silicon dioxide/graphene composite aerogel and composite aerogel obtained thereby

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] At room temperature, ultrasonically disperse 0.05 g of ethoxysilanized graphene 1 in 50 ml of acetone, add 0.1 mol / L oxalic acid aqueous solution to adjust the pH to 3.5 for hydrolysis, and obtain hydrolyzate 1A.

[0035] At room temperature, 100 g of tetraethyl orthosilicate, 600 g of acetone and 35 g of deionized water were mixed, and oxalic acid was added to adjust the pH to 3.5 for hydrolysis to obtain hydrolyzate 1B.

[0036] Mix the hydrolyzate 1A and the hydrolyzate 1B evenly, add ammonia water to adjust the pH to 11.0 to condense to obtain a wet gel; place the wet gel in a water bath at 30°C for aging for 4 hours, take out the wet gel and soak it in absolute ethanol for 2 Carry out solvent replacement every hour, solvent replacement is carried out 3 times, take out wet gel again and soak in the n-hexane solution of trimethylchlorosilane (the volume ratio of trimethylchlorosilane and n-hexane is 1:7) in 3 hours, take out wet gel Gel was dried by freeze-drying met...

Embodiment 2

[0038] At room temperature, ultrasonically disperse 0.2 g of ethoxysilanized graphene 2 in 60 ml of absolute ethanol, add 0.1 mol / L oxalic acid aqueous solution to adjust the pH to 3.0 for hydrolysis, and obtain hydrolyzate 2A.

[0039] At room temperature, 100 g of ethyl orthosilicate, 600 g of absolute ethanol and 35 g of deionized water were mixed, and oxalic acid was added to adjust the pH to 3.5 for hydrolysis to obtain hydrolyzate 2B.

[0040]Mix hydrolyzate 2A and hydrolyzate 2B evenly, add ammonia water to adjust the pH to 11.0 and condense to obtain a wet gel; place the wet gel in a water bath at 30°C for aging for 4 hours, take out the wet gel and soak it in absolute ethanol for 1.5 Carry out solvent replacement every hour, solvent replacement is carried out 3 times, take out wet gel again and soak in the n-hexane solution of trimethylchlorosilane (the volume ratio of trimethylchlorosilane and n-hexane is 1:7) in 3 hours, take out wet gel The gel was sequentially dri...

Embodiment 3

[0042] At room temperature, ultrasonically disperse 0.4 g of ethoxysilanized graphene 3 in 70 ml of absolute ethanol, add 0.1 mol / L oxalic acid aqueous solution to adjust the pH to 3.0 for hydrolysis, and obtain hydrolyzate 3A.

[0043] Mix hydrolyzate 3A and hydrolyzate 2B evenly, add ammonia water to adjust the pH to 11.0 to condense to obtain a wet gel; place the wet gel in a water bath at 40°C for aging for 3.5 hours, take out the wet gel and soak it in absolute ethanol for 2 Carry out solvent replacement every hour, solvent replacement is carried out 3 times, take out wet gel again and soak in the n-hexane solution of trimethylchlorosilane (the volume ratio of trimethylchlorosilane and n-hexane is 1:7) in 3 hours, take out wet gel The gel was sequentially dried in a blast drying oven at 40°C for 2.5 hours, in a blast drying oven at 80°C for 2.5 hours, and in a blast drying oven at 120°C for 1.5 hours to obtain a silica-graphene composite airgel 3.

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Abstract

The invention relates to the technical field of aerogel and particularly relates to a method for preparing silicon dioxide/graphene composite aerogel and the composite aerogel obtained thereby. The method comprises the steps of subjecting graphene oxide and amino-containing trialkoxysilane to a reaction so as to obtain alkoxy silanized graphene, ultrasonically dispersing the alkoxy silanized graphene in an organic solvent for hydrolyzing so as to obtain a hydrolyzate A, hydrolyzing a conventional silicon source so as to obtain a hydrolyzate B, uniformly mixing the hydrolyzate A and the hydrolyzate B, carrying out alkaline condensation so as to obtain wet gel, then, carrying out ageing, solvent replacement and surface modification, and then, carrying out drying, thereby obtaining the silicon dioxide/graphene composite aerogel. The silicon dioxide/graphene composite aerogel disclosed by the invention has relatively high mechanical strength, and the coefficient of high-temperature thermalconductivity of silicon dioxide aerogel is lowered due to presence of graphene, so that the silicon dioxide/graphene composite aerogel can be applied to the fields of heat-preserving heat-insulatingmaterials and the like.

Description

technical field [0001] The invention relates to the technical field of airgel, in particular to a method for preparing a silica / graphene composite airgel and the obtained composite airgel. Background technique [0002] Due to its high specific surface area, low thermal conductivity, low density, and unique electrical conductivity, silica airgel has attracted extensive attention from developers in the industry. Its main application prospect is thermal insulation materials. However, as the temperature increases, the infrared heat radiation permeability of silica airgel increases. In order to further reduce high-temperature infrared heat radiation, opacifying agents, such as carbon black and titanium dioxide, are usually added to silica airgel. , but will lead to the reduction of other properties of silica. [0003] Graphene airgel is another kind of airgel, which also has high specific surface area, low density and other properties, and has good elasticity. Combining the adv...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/158C01B32/194
CPCC01B33/1585C01P2004/80C01P2006/10C01P2006/12C01P2006/32C01B32/194
Inventor 杨金兰
Owner 江苏和硅纳米科技有限公司
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