Normal pressure dried phenolic aerogel and preparation method thereof

A technology of atmospheric drying and phenolic gel, applied in the field of nanomaterials, can solve the problems of high shrinkage rate of phenolic aerogel, weak skeleton of phenolic aerogel, poor process performance, etc., and achieve good oxidation resistance and burning resistance. Corrosion performance, skeleton strength improvement, shrinkage reduction effect

Pending Publication Date: 2019-11-05
AEROSPACE INST OF ADVANCED MATERIALS & PROCESSING TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a kind of normal pressure drying phenolic airgel and preparation method thereof, to solve the problem that the weak skeleton of the phenolic airgel in the prior art can not be dried under normal pressure, and the shrinkage rate of the existing normal pressure drying phenolic aerogel Problems such as large or poor process performance

Method used

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  • Normal pressure dried phenolic aerogel and preparation method thereof
  • Normal pressure dried phenolic aerogel and preparation method thereof
  • Normal pressure dried phenolic aerogel and preparation method thereof

Examples

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preparation example Construction

[0030] The present invention provides a kind of preparation method of normal pressure drying phenolic airgel in the first aspect, described method comprises the steps:

[0031] (1) prepare the grafting reaction solution that comprises novolac resin, silane grafting agent and the first organic solvent, make described novolac resin and silane grafting agent carry out grafting reaction in described grafting reaction solution, obtain silane Grafted phenolic resin;

[0032] (2) adding a curing agent and a second organic solvent to form a curing reaction solution and carry out a curing reaction to obtain a phenolic gel;

[0033] (3) Drying the phenolic gel under normal pressure to obtain the phenolic aerogel.

[0034]In the present invention, first adopt silane grafting agent to carry out grafting reaction to novolac resin, the present invention unexpectedly finds that compared with directly blending silane monomer with phenolic resin or phenolic small molecule monomer, adopting th...

Embodiment 1

[0040] Weigh novolac resin and tetraethyl orthosilicate with a hydroxyl molar ratio of 1:1, dissolve in ethanol solution, prepare a uniform grafting reaction solution, and place it in a three-necked round-bottomed flask. The mass fraction of novolak resin in the grafting reaction solution is 45wt%. 1 wt% acetic acid based on the mass of phenolic resin was added as a grafting catalyst, and the grafting reaction was carried out under reflux at 95° C. for 12 hours.

[0041] Cool down to room temperature after the reaction is over, add ethanol to adjust the solid content to 35wt%, add 10wt% hexamethylenetetramine of the phenolic resin quality as a curing agent, stir until it is completely dissolved, and obtain a solidified reaction solution. The time of standing 72h does not produce gel. Put the curing reaction solution into a metal mold that can be sealed and withstand high pressure, so that the mold cavity is filled and sealed, and placed in an oven at 120° C. for 72 hours to c...

Embodiment 2~14

[0044] The process parameters adopted in Examples 2 to 14 are shown in Table 1. Except for the listed parameters, the other unmentioned process parameters are the same as those in Example 1.

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Abstract

The invention provides a method for preparing a phenolic aerogel by normal pressure drying. The method comprises the following steps: preparing a graft reaction solution including a phenolic novolac resin, a silane grafting agent and a first organic solvent, and carrying out a grafting reaction the phenolic novolac resin and the silane grafting agent in the graft reaction solution to obtain a silane-grafted phenolic resin; adding a curing agent and a second organic solvent to form a curing reaction solution, and performing a curing reaction to obtain a phenolic gel; and drying the phenolic gelunder normal pressure to obtain the phenolic aerogel. The invention also provides the phenolic aerogel produced by the method. The method of the invention realizes normal pressure drying, greatly shortens the preparation cycle, reduces the preparation cost, solves the problems of microscopic phase separation and too fast gelling, and leaves sufficient operation time for practical application. Theprepared phenolic aerogel has a significantly improved framework strength, a remarkably reduced shrinkage, good oxidation resistance and good ablation resistance.

Description

technical field [0001] The invention relates to the technical field of nanometer materials, in particular to a normal-pressure dry phenolic airgel and a preparation method thereof. Background technique [0002] Airgel material is a high-performance nanoporous material, which is composed of nano-particles on the microcosm to form a three-dimensional nanoporous structure, which has the characteristics of low density, high specific surface area, high porosity, and low thermal conductivity. It can be widely used as heat insulation materials, sound-absorbing materials, catalytic materials, and adsorption materials. In particular, aerogels made of high-temperature-resistant or ablation-resistant material substrates have played a huge role in the field of high-temperature heat insulation as thermal protection materials for aerospace vehicles. [0003] Phenolic aerogels are an important class of airgel materials, which can be carbonized at high temperatures, can resist harsh high h...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/28C08G8/28C08L61/14
CPCC08G8/28C08J9/28C08J2361/14
Inventor 刘圆圆徐春晓刘韬宋寒郭慧张凡李文静杨洁颖赵英民张昊
Owner AEROSPACE INST OF ADVANCED MATERIALS & PROCESSING TECH
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