Normal pressure preparation method for silicon dioxide/attapulgite fiber compound aerogel

A technology of attapulgite and silica, applied in the field of preparation of silica aerogel, can solve the problems of powder and small fragments, and achieve the effects of low thermal conductivity, shortened preparation period and good biological adaptability

Active Publication Date: 2018-09-04
XUYI BOTU ATTAPULGITE CLAY HIGH TECH DEV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a normal-pressure preparation method of silica / attapulgite fiber composite airgel, which overcomes the problem of powder and small fragments in the airgel in the preparation of general normal-pressure drying methods, and realizes normal pressure. Preparation of silica / attapulgite fiber composite monolithic airgel with hydrophobic or hydrophilic properties by pressing

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  • Normal pressure preparation method for silicon dioxide/attapulgite fiber compound aerogel
  • Normal pressure preparation method for silicon dioxide/attapulgite fiber compound aerogel
  • Normal pressure preparation method for silicon dioxide/attapulgite fiber compound aerogel

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preparation example Construction

[0043] A normal-pressure preparation method of silica / attapulgite fiber composite airgel, comprising the following steps:

[0044] (1) After uniformly mixing the organosilicon precursor, absolute ethanol and deionized water, add an acidic catalyst until the pH is 2-3, and hydrolyze for 30 minutes to obtain a silica sol;

[0045] (2) Add the attapulgite fiber that has been pretreated by pickling, mix well, adjust the pH to 6-8 with a carbonate / ammonia water mixed solution, transfer it to a mold and let it stand to obtain silica / attapulgite fiber Composite hydrogel, aged at 20-60°C for 24-48 hours;

[0046] (3) Take the silica / attapulgite fiber composite hydrogel out of the mold, and immerse it in an aqueous sodium bicarbonate solution for solvent replacement for 12 to 24 hours;

[0047] (4) The silica / attapulgite fiber composite hydrogel after solvent replacement is taken out, and after being fully dried, a hydrophilic silica / attapulgite fiber composite airgel is obtained.

Embodiment 1

[0049] At room temperature (25°C), mix tetraethyl orthosilicate, absolute ethanol and deionized water according to the molar ratio of 1:7:4 and stir evenly, add hydrochloric acid and oxalic acid mixture to adjust the pH to 2, stir for 30min, and 3wt.% attapulgite fibers with a diameter of 20-40nm and a length of 0.5-1.5μm that have been pretreated by pickling are added to the mixed solution and ultrasonically treated for 10 minutes to make them evenly dispersed; add sodium carbonate / ammonia water mixed solution to adjust the pH To 6, after stirring, seal and stand still to obtain silica / attapulgite fiber composite hydrogel; add 40mL absolute ethanol to the obtained silica / attapulgite fiber composite hydrogel, seal and place at 20 Aging in a water bath at ℃ for 24 hours; after aging, the silica / attapulgite fiber composite hydrogel was taken out of the mold, immersed in 0.04mol / L sodium bicarbonate aqueous solution for solvent replacement for 12 hours; after replacement, it was d...

Embodiment 2

[0051] At room temperature (25°C), mix tetraethyl orthosilicate, absolute ethanol and deionized water according to the molar ratio of 1:7:8 and stir evenly, add acetic acid to adjust the pH to 3, stir for 30min, and add 15wt.% Add the attapulgite fibers with a diameter of 20-40nm and a length of 0.5-1.5μm after pickling pretreatment into the mixed solution for ultrasonic treatment for 10 minutes to make them uniformly dispersed; add sodium bicarbonate / ammonia water mixed solution to adjust the pH to 7, After stirring, seal and stand still to obtain silica / attapulgite fiber composite hydrogel; add 40mL of absolute ethanol to the obtained silica / attapulgite fiber composite hydrogel, seal and place in a 40°C water bath Medium aging for 36 hours; after aging, the silica / attapulgite fiber composite hydrogel was taken out of the mold, immersed in 0.1mol / L sodium bicarbonate aqueous solution for solvent replacement for 18 hours; after replacement, it was dried at 60°C for 15 minutes, ...

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Abstract

The invention discloses a normal pressure preparation method for silicon dioxide / attapulgite fiber compound aerogel. The preparation method comprises the following steps: uniformly mixing an organic silicon precursor, absolute ethyl alcohol and deionized water, and adding an acidic catalyst till the pH value is 2-3 to obtain silicon dioxide sol; adding attapulgite fibers and uniformly mixing the mixture to adjust the pH value to 6-8 by means of a carbonate / ammonia water mixed solution, transferring the solution to a mold to stand to obtain a silicon dioxide / attapulgite fiber compound aerogel and ageing the same; taking the silicon dioxide / attapulgite fiber compound aerogel out of the mold and impregnating the same in a sodium hydrogen carbonate aqueous solution to replace a solvent; and fully drying the same after replacement to obtain the hydrophilic silicon dioxide / attapulgite fiber compound aerogel. The method provided by the invention overcomes the problem that the aerogel has powder and small fragments by a common normal pressure drying method, so that the whole aerogel with lyophobic or hydrophilic characteristics is prepared at normal pressure.

Description

technical field [0001] The invention relates to the preparation of silica airgel, in particular to a normal-pressure preparation method of silica / attapulgite fiber composite airgel. Background technique [0002] Silicon dioxide (SiO 2 ) Airgel is a nanoporous amorphous solid material with a spatial network structure composed of colloidal particles. Its porosity can reach 80%-99.9%, and the pore size and skeleton particle size are respectively between 5-70nm and 1-50nm. Silica airgel has many unique properties, such as high specific surface area, high porosity, high thermal insulation, low density, etc. Due to the above-mentioned unique properties of silica airgel, it has broad and huge application prospects in the fields of optics, heat insulation, acoustics, catalyst carrier, microelectronics, chemical industry, aerospace and other fields. [0003] In the process of preparing silica airgel, the key process is the drying process of wet gel. Due to the existence of capill...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B30/02C04B38/02C04B14/46C04B14/06
CPCC04B30/02C04B38/02C04B2201/20C04B2201/32C04B2201/50C04B14/064C04B14/4656
Inventor 郭建军陈凯周灿伟刘丰华许高杰
Owner XUYI BOTU ATTAPULGITE CLAY HIGH TECH DEV
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