Preparation method of high-temperature-resistant ultralow-density silicon carbide nanotube aerogel

A density silicon carbide and airgel technology, applied in the direction of airgel preparation, chemical instruments and methods, carbon compounds, etc., can solve the problem of high gel density

Inactive Publication Date: 2020-10-23
HUAIYIN INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing high-temperature-resistant ultra-low-density silicon carbide aerogels, whic...

Method used

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  • Preparation method of high-temperature-resistant ultralow-density silicon carbide nanotube aerogel
  • Preparation method of high-temperature-resistant ultralow-density silicon carbide nanotube aerogel
  • Preparation method of high-temperature-resistant ultralow-density silicon carbide nanotube aerogel

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Dissolve methyltrimethoxysilane, dimethyldimethoxysilane and cetyltrimethylammonium bromide in deionized water to obtain a transparent solution, in which methyltrimethoxysilane, dimethyldimethoxy The mol ratio of base silane, cetyltrimethylammonium bromide, deionized water is 1:0.1: 0.1: 80; Add 2 mol / L ammoniacal liquor in above-mentioned solution and regulate solution pH and be 9.0 and form gel, will The gel was soaked in absolute ethanol three times, each time for 12 h; the soaked gel was directly put into an oven for drying under normal pressure at 80 °C for 48 h to obtain polyalkylsiloxane airgel. The average pore diameter of the prepared polyalkylsiloxane airgel is 2200 nm.

[0029] Immerse the polyalkylsiloxane airgel in a xylene solution containing 1% polycarbosilane until the solution completely wets the gel, and dry the wetted polyalkylsiloxane airgel in vacuum ( The vacuum degree is less than 20Pa, and the drying temperature is 30°C) to obtain the polyalkyls...

Embodiment 2

[0032] Dissolve methyltrimethoxysilane, dimethyldimethoxysilane and cetyltrimethylammonium bromide in deionized water to obtain a transparent solution, in which methyltrimethoxysilane, dimethyldimethoxy The mol ratio of base silane, cetyltrimethylammonium bromide, deionized water is 1:0.2: 0.2: 60; Add 3 mol / L ammoniacal liquor in above-mentioned solution and regulate solution pH value and be 10.0 and form gel, will The gel was soaked in absolute ethanol three times, each time for 12 h; the soaked gel was directly put into an oven for drying under normal pressure at 100 °C for 48 h to obtain polyalkylsiloxane airgel. The average pore diameter of the prepared polyalkylsiloxane airgel was 1200 nm.

[0033] Immerse the polyalkylsiloxane airgel in a xylene solution containing 2% polycarbosilane until the solution completely wets the gel, and dry the wetted polyalkylsiloxane airgel in vacuum ( The vacuum degree is less than 20Pa, and the drying temperature is 40°C) to obtain polya...

Embodiment 3

[0036] Dissolve ethyltrimethoxysilane, dimethyldiethoxysilane and cetyltrimethylammonium bromide in deionized water to obtain a transparent solution, in which ethyltrimethoxysilane, dimethyldiethoxy The mol ratio of base silane, hexadecyltrimethylammonium bromide, deionized water is 1:0.5:0.3:60; Add 3 mol / L ammoniacal liquor in above-mentioned solution and regulate solution pH value and be 11.0 and form gel, will The gel was soaked in absolute ethanol three times, each time for 12 h; the soaked gel was directly put into an oven for drying under normal pressure at a drying temperature of 120 °C for 30 h to obtain polyalkylsiloxane airgel. The average pore diameter of the prepared polyalkylsiloxane airgel was 820 nm.

[0037] Immerse the polyalkylsiloxane airgel in a xylene solution containing 3% polycarbosilane until the solution completely wets the gel, and dry the wetted polyalkylsiloxane airgel in vacuum ( The vacuum degree is less than 20Pa, and the drying temperature is ...

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Abstract

The invention discloses a preparation method of high-temperature-resistant ultralow-density silicon carbide nanotube aerogel. The preparation method of the aerogel comprises the following specific steps: (1) dissolving alkyl trialkoxy silane, dialkyl dialkoxy silane and hexadecyl trimethyl ammonium bromide in deionized water to obtain a transparent solution, wherein the molar ratio of alkyl trialkoxy silane to dialkyl dialkoxy silane to hexadecyl trimethyl ammonium bromide to deionized water is 1: (0.1-1): (0.1-0.5): (40-80); according to the preparation method disclosed by the invention, thepoly alkyl siloxane gel with a macroporous structure is obtained by utilizing phase separation of alkyl siloxane in a sol-gel process in a water system, the capillary force in a normal-pressure process can be greatly reduced by the macroporous structure, a low-density aerogel block can be obtained under normal-pressure drying, and the preparation method is simpler.

Description

technical field [0001] The invention belongs to the field of porous material preparation, and in particular relates to a preparation method of high-temperature-resistant ultra-low-density silicon carbide airgel. Background technique [0002] Airgel is a new material with three-dimensional nanoporous structure, which has low density (0.003-0.8 g cm-3), high porosity (80-99.8%), high specific surface area (200-1000 m2 g- 1), low thermal conductivity (~0.02 W m-1K-1) and other properties, it has very broad prospects in aerospace, chemical industry, energy-saving buildings, military, communications, electronics, metallurgy and other application fields. However, traditional silica aerogels sinter at high temperatures exceeding 650 °C, resulting in the collapse of the nanopore structure and performance degradation, making it difficult to apply to high-temperature applications. [0003] Silicon carbide airgel has attracted attention because of its ability to withstand high tempera...

Claims

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Application Information

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IPC IPC(8): C01B32/977B01J13/00
CPCB01J13/0091C01P2002/72C01P2004/61C01P2004/62C01B32/977
Inventor 云山郭探李彦兴李爱平徐海青洪坤陈静
Owner HUAIYIN INSTITUTE OF TECHNOLOGY
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