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Method for preparing silicon oxide aerogel with low cost

A silica airgel, a low-cost technology, applied in the direction of silica, silica, etc., can solve the problems of increasing preparation costs, inability to produce continuously, and restricting the industrial application of airgel

Inactive Publication Date: 2017-02-22
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Chinese patents CN201210121968.0 and CN201210114691.9 use sodium silicate as a raw material and are prepared by a two-step sol-gel method. After ion exchange, they are aged with an ethanol solution of tetraethyl orthosilicate, and finally undergo solvent exchange and modification. Airgel is obtained by drying, and the tetraethyl orthosilicate used greatly increases the preparation cost, and the density of the obtained airgel is also relatively high
Due to the limited capacity of the cation exchange resin (generally 5 mmol / g), the experimental level of this method is acceptable. If it is industrialized production, the high concentration of sodium ions in the water glass will cause the exchange capacity of the ion exchange resin to quickly saturate, and continuous production cannot be achieved at all.
At present, there are many research reports on the preparation of silica airgel by atmospheric drying, but there are certain defects, such as high cost, complicated process, and the prepared airgel has a small specific surface area and poor temperature resistance, which restricts the Industrial applications of airgel

Method used

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  • Method for preparing silicon oxide aerogel with low cost

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Take 20ml of industrial water glass with a modulus of 3.2 according to the volume ratio of industrial water glass and water 1:4, mix 80ml of deionized water in a beaker, stir for 10min, then filter and ultrasonicate for 5min, add 0.47ml to the solution Glycerol, stir for 3 minutes, add 8.4ml of 1mol / L oxalic acid solution, stir for 1 minute, wait for it to completely gel, add deionized water, then place it in a 40°C water bath for two days, and then replace it with ethanol for one day, Then, the wet gel was replaced in n-hexane, and the wet gel was modified in a mixture of trimethylchlorosilane and n-hexane for 10 h in a water bath at 40°C. The fully modified gel floats on the modified liquid product as a whole, then is replaced by n-hexane for 24 hours, and finally dried at 40°C, 60°C, 80°C, and 100°C for two hours each to obtain an airgel sample.

[0024] The obtained airgel sample density is 0.068g / cm 3 , the specific surface area is 699.8m 2 / g.

Embodiment 2

[0026] Measure 20ml of industrial water glass with a modulus of 3.2 according to the volume ratio of industrial water glass and water 1:4, mix 80ml of deionized water in a beaker, stir for 10min, then filter and ultrasonicate for 10min, add 0.47ml to the solution Glycerol, stir for 3 minutes, add 8.7ml of 1mol / L oxalic acid solution, stir for 1 minute, wait until it is completely gelled, add deionized water, then put it in a 40°C water bath for two days, and then replace it with ethanol for one day, Then, the wet gel was replaced in n-hexane, and the wet gel was modified in a mixture of trimethylchlorosilane and n-hexane for 10 h in a water bath at 40°C. The fully modified gel floats on the modified liquid product as a whole, then is replaced by n-hexane for 24 hours, and finally dried at 40°C, 60°C, 80°C, and 100°C for two hours each to obtain an airgel sample.

[0027] The obtained airgel sample density is 0.070g / cm 3 , the specific surface area is 607.7m 2 / g.

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Abstract

The invention relates to a method for preparing silicon oxide aerogel with low cost. Cheap industrial water glass is adopted as a precursor, water is adopted as a reactive solvent, oxalic acid is adopted as an acid catalyst, and the high-temperature-resistant blocky silicon oxide aerogel with excellent performance is prepared through a normal-pressure drying process. The prepared aerogel sample is low in density, high in specific area and good in temperature resistance, and the hydrophobic temperature resistance in air can reach 400 DEG C. The method has the advantages of being simple in preparation process and low in cost, the application range of the aerogel is widened through excellent high-temperature stability of the prepared aerogel, and the aerogel can be widely applied to the field of heat insulation.

Description

technical field [0001] The invention belongs to the technical field of preparation of inorganic nanoporous materials, and relates to a method for preparing silica airgel at low cost. Background technique [0002] Airgel is a highly dispersed solid-state material in which colloidal particles or polymer molecules are aggregated into a nanoporous network structure, and the pores are filled with a gaseous dispersion medium. This material with a sponge-like open-pore structure has a very large specific surface area, and the structure of the material can be controlled at the microscopic scale of nanometer scale, so that it has many unique properties. The unique structural characteristics of aerogels make aerogels have singular properties in thermal, electrical, acoustic, optical and other aspects. [0003] SiO 2 The preparation of airgel usually uses supercritical drying, the molding effect is better, and the nanoporous network structure can be well maintained. However, the equ...

Claims

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Application Information

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IPC IPC(8): C01B33/16
Inventor 陈晓红王美月宋怀河张建凯蒋文静
Owner BEIJING UNIV OF CHEM TECH