Method for quickly preparing carbon-silicon dioxide composite aerogel

A composite airgel and silica technology, applied in the direction of silica, silica, etc., can solve the problems of long co-gelation and aging time, complicated preparation process, high reaction temperature requirements, etc., to achieve gel and The effects of short aging time, simple preparation process and high preparation efficiency

Inactive Publication Date: 2011-03-16
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, using this method to prepare materials often requires step-by-step preparation of carbon and silica precursor sols, and the time for co-gela

Method used

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  • Method for quickly preparing carbon-silicon dioxide composite aerogel
  • Method for quickly preparing carbon-silicon dioxide composite aerogel
  • Method for quickly preparing carbon-silicon dioxide composite aerogel

Examples

Experimental program
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Effect test

Embodiment 1

[0027] (1) Mix resorcinol and formaldehyde in acetonitrile at a molar ratio of 1:2 at room temperature, then add hydrochloric acid as an acidic catalyst, then add tetraethyl orthosilicate, deionized water and hydrofluoric acid solution in sequence, After stirring evenly, a mixed sol was formed, sealed and left standing at room temperature, and the gel and aging time were 1440 minutes. The molar ratio of added resorcinol, tetraethylorthosilicate, water, hydrogen chloride, hydrogen fluoride and acetonitrile is 1:2:6:0.04:0.5:20.

[0028] (2) Soak the obtained wet gel in acetone for three times of solvent replacement, each time for 8 hours. followed by supercritical fluid CO 2 Dry (40°C, 10MPa) for 4 hours to obtain resorcinol formaldehyde-silica composite airgel.

[0029] (3) Carbonize the obtained composite airgel at 700°C for 1 hour under the protection of nitrogen to obtain a carbon-silica composite airgel with a density of 200mg / cm 3 Around 90% porosity and about 30% carb...

Embodiment 2

[0031] (1) Mix resorcinol and formaldehyde in acetonitrile at a molar ratio of 1:2 at room temperature, then add hydrochloric acid as an acidic catalyst, then add tetraethyl orthosilicate, deionized water and hydrofluoric acid solution in sequence, After stirring evenly, a mixed sol was formed, which was sealed and left standing at 80° C., and the gel time was 10 minutes. The molar ratio of added resorcinol, tetraethylorthosilicate, water, hydrogen chloride, hydrogen fluoride and acetonitrile is 1:2:6:0.04:0.5:20.

[0032] (2) Soak the obtained wet gel in ethanol for solvent replacement 3 times, 8 hours each time. Then supercritical ethanol drying (255°C, 7MPa) was carried out for 1 hour to obtain resorcinol formaldehyde-silica composite airgel, the physical appearance is as follows figure 1 as shown in a.

[0033] (3) Carbonize the obtained composite airgel at 700°C for 2 hours under the protection of nitrogen to obtain a carbon-silica composite airgel with a density of 200...

Embodiment 3

[0035](1) Mix resorcinol and formaldehyde in acetonitrile at a molar ratio of 1:2 at room temperature, then add hydrochloric acid as an acidic catalyst, then add tetraethyl orthosilicate, deionized water and hydrofluoric acid solution in sequence, After stirring evenly, a mixed sol was formed, sealed and left standing at room temperature, and the gel and aging time were 1440 minutes. The molar ratio of added resorcinol, tetraethylorthosilicate, water, hydrogen chloride, hydrogen fluoride and acetonitrile is 1:1.5:4.5:0.03:0.37:14.

[0036] (2) Soak the obtained wet gel in ethanol for 6 times of solvent replacement, 4 hours each time. Then perform supercritical ethanol drying (245°C, 10MPa) for 1 hour to obtain resorcinol formaldehyde-silica composite airgel.

[0037] (3) Carbonize the obtained composite airgel at 700°C for 2 hours under the protection of nitrogen to obtain a carbon-silica composite airgel with a density of about 300mg / cm 3 , the porosity is above 90%, and th...

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Abstract

The invention relates to a method for quickly preparing carbon-silicon dioxide composite aerogel. In the method, resorcinol, formaldehyde and tetraethoxysilane are taken as reactants, and a low-density and high-porosity carbon-silicon dioxide composite aerogel material is prepared by combining a sol-gel method under the catalysis of composite acid in an adjustable proportion with a special drying and carbonizing process. Compared with the conventional method for preparing similar materials under the catalysis of alkali, the preparation method has the advantages that: by a one-pot sol-gel synthesis process, the solation and gelation processes of two precursors, namely carbon and silicon dioxide are performed simultaneously, and the components of the material are more uniformly compounded; and gelation time and ageing time are short, preparation efficiency is high, the preparation process is simple, the method can be operated at room temperature, and the like. The prepared material can be used for the fields of adsorption filtration, catalysis, energy, aerospace, laser inertial confinement fusion target materials and the like.

Description

technical field [0001] The invention belongs to the field of preparation of carbon-silicon dioxide composite airgel materials, and in particular relates to a compound acid catalyzed sol-gel technology and a one-pot method for rapidly preparing carbon-silicon dioxide composite airgel. Background technique [0002] Airgel is currently the lightest solid material in the world. It has a continuous three-dimensional nanoporous network structure and is known as "solid smog". Its low density, large specific surface area, high porosity and flexible and controllable structure make this material have unique mechanical, thermal, optical, electrical and acoustic properties. Aerospace, nuclear fusion experiments, military and energy fields have broad application prospects, so they have become one of the hot spots in the field of material research at home and abroad in recent years. [0003] Silica airgel was first prepared by Kistler S. S. of Stanford University in 1931 by using sol-gel...

Claims

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Application Information

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IPC IPC(8): C01B33/16C01B31/02
Inventor 周斌陈珂包志豪杜艾沈军
Owner TONGJI UNIV
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