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Preparation method of boron-modified phenolic aerogel

A boron-modified and aerogel technology is applied in the field of preparation of boron-modified phenolic aerogels to achieve the effects of improving ablation resistance, low reaction conditions, low thermal conductivity and density

Pending Publication Date: 2021-01-05
AEROSPACE INST OF ADVANCED MATERIALS & PROCESSING TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Aiming at the requirements of anti-heat insulation, ablation resistance and light weight proposed for phenolic thermal protection materials in the field of aerospace vehicles, the present invention provides a preparation method of boron-modified ablation-resistant phenolic aerogels. The process of gel sol-gel reaction is controlled, and organic boron sources such as tributyl borate are uniformly introduced into the phenolic organogel network structure, and light ablation-resistant boron-modified phenolic airgel materials are successfully prepared

Method used

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  • Preparation method of boron-modified phenolic aerogel
  • Preparation method of boron-modified phenolic aerogel
  • Preparation method of boron-modified phenolic aerogel

Examples

Experimental program
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Effect test

Embodiment 1

[0049] (1) Preparation of sol: dissolving novolac resin in absolute ethanol solution, stirring at room temperature for 3 hours to prepare a novolac ethanol solution with a mass fraction of 30 wt%. Subsequently, tributyl borate accounting for 20 wt% of the phenolic mass ratio was added to the above-mentioned phenolic ethanol solution and stirred for 1 hour to dissolve. Add 10 wt% of the cross-linking agent hexamethylenetetramine to the above mixed solution, and stir at room temperature for 2 hours to dissolve the hexamethylenetetramine, and the viscosity of the sol system remains unchanged.

[0050] (2) Sol-gel curing: the above clear solution was placed in a closed container, heated in an oven at 120° C., and boron-modified phenolic wet gel was obtained after sol-gel reaction for 12 hours.

[0051] (3) Atmospheric pressure drying: take out the wet gel, let it air naturally for 24 hours, and then dry it at 60 degrees Celsius under normal pressure for 12 hours to obtain an ablat...

Embodiment 2

[0054] (1) Preparation of sol: dissolving novolac resin in absolute ethanol solution, stirring at room temperature for 3 hours to prepare a novolac ethanol solution with a mass fraction of 25 wt%. Subsequently, triisopropyl borate accounting for 20 wt% of the phenolic mass ratio was added to the above-mentioned novolac ethanol solution and stirred for 1 h to dissolve. Add 10wt% crosslinking agent hexamethylenetetramine to the above mixed solution, and stir at room temperature for 2 hours to dissolve the hexamethylenetetramine, and the viscosity of the sol system increases to form a uniform suspension.

[0055] (2) Sol-gel curing: put the above suspension in a closed container, heat in an oven at 120° C., and obtain a boron-modified phenolic wet gel after sol-gel reaction for 12 hours.

[0056] (3) Atmospheric pressure drying: take out the wet gel, let it hang naturally for 24 hours, and then dry it at 60 degrees Celsius under normal pressure for 12 hours to obtain a boron-modi...

Embodiment 3

[0059] (1) Preparation of sol: dissolving novolac resin in absolute ethanol solution, stirring at room temperature for 3 hours to prepare a novolac ethanol solution with a mass fraction of 30 wt%. Then add triphenyl borate accounting for 25% by mass ratio of phenolic formaldehyde and stir and dissolve for 1 h, add 10 wt % cross-linking agent hexamethylenetetramine accounting for phenolic mass ratio to the above mixed solution, stir at room temperature for 2 hours to make hexamethylenetetramine Dissolve to obtain a homogeneous suspension.

[0060] (2) Sol-gel curing: put the above suspension in a closed container, heat in an oven at 120° C., and obtain boron carbide composite boron phenolic wet gel after sol-gel reaction for 12 hours.

[0061] (3) Atmospheric pressure drying: take out the wet gel, let it hang naturally for 24 hours, and then dry it at 60 degrees Celsius under normal pressure for 12 hours to obtain a boron-modified phenolic airgel product.

[0062] Scanning ele...

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Abstract

The invention relates to a preparation method of a boron-modified phenolic aerogel. The method comprises the following steps of: dissolving linear phenolic resin, tributyl borate and other organic boric acids in an ethanol solution, adding a cross-linking agent hexamethylenetetramine, carrying out an initial low-viscosity sol-gel process to obtain a boron composite phenolic wet gel, and carrying out normal-pressure drying to obtain the boron modified phenolic aerogel. And tributyl borate and other organic boron sources can be uniformly mixed in the solution, so that the viscosity of the systemis unchanged or slowly rises, thereby effectively ensuring the stability of the glue injection process. In addition, boron particles form boron oxide in the ablation application process, and the boron oxide permeates into gaps of the phenolic aerogel to fill the gaps of the phenolic aerogel and melt and coat a phenolic matrix. The prepared boron-modified phenolic aerogel has the advantages of good specific surface area, oxidation resistance, low heat conductivity coefficient and density, good processability and the like, can maintain the original shape and performance at high temperature, andis expected to be applied to the field of external thermal protection of high-speed aircrafts.

Description

technical field [0001] The invention relates to a preparation method of boron-modified phenolic airgel, which belongs to the technical field of phenolic resin materials and aircraft thermal protection. Background technique [0002] When a space vehicle flies in the atmosphere at high speed, due to the intense friction and compression between the airflow and the surface of the vehicle, the gas in the boundary layer heats up rapidly and heats up the vehicle, which is called aerodynamic heating. For re-entry aircraft, the surface temperature can reach above 2000°C, and for cruise aircraft, the surface temperature can reach above 1000°C. Severe aerodynamic heating will have a serious impact on the aircraft body structure and internal equipment. Thermal protection materials must be used to protect the aircraft from damaged. For high-speed aircraft with a flight speed of more than Mach 5, thermal protection technology has become one of the key technologies as important as the eng...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/28C08G8/28C08L61/14
CPCC08J9/28C08G8/28C08J2361/14C08J2205/026C08J2201/0502
Inventor 徐春晓刘圆圆张贝贝刘韬郭慧孔德隆李文静刘瑾杨洁颖张昊
Owner AEROSPACE INST OF ADVANCED MATERIALS & PROCESSING TECH
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