A kind of method for preparing polyimide modified phenolic airgel

A polyimide, polyimide precursor technology, applied in the field of foam materials, can solve the problems of poor processing and molding stability, low strength and rigidity, difficult drying methods, etc., to enhance toughness, enhance mechanical properties, The effect of increasing the heat resistance range

Active Publication Date: 2017-01-11
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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  • Abstract
  • Description
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AI Technical Summary

Problems solved by technology

[0004] In order to solve the defects and deficiencies existing in existing phenolic aerogels, such as poor toughness, poor impact strength, low strength and rigidity, difficult drying methods, poor processing stability, and short service life, the invention provides a polyimide The preparation method of (PI) modified phenolic aerogel, technique is simple and feasible, can economically and efficiently prepare the modified phenolic aerogel with excellent overall performance and controllable density, the present invention is achieved in this way:

Method used

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  • A kind of method for preparing polyimide modified phenolic airgel
  • A kind of method for preparing polyimide modified phenolic airgel
  • A kind of method for preparing polyimide modified phenolic airgel

Examples

Experimental program
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Embodiment 1

[0026] Embodiment 1 prepares polyimide

[0027] Dissolve the diamine (the diamine selected in this embodiment is 4,4'-diaminodiphenylmethane) in dimethylacetamide, add pyromellitic dianhydride, the added 4,4'-diamino The molar ratio of diphenylmethane to pyromellitic dianhydride is 1:1.05, stir and react for 4 hours, then add 0.1mL 3-aminopropyltrimethoxysilane dropwise, continue to stir and react for 4 hours, and the reaction product is first washed with deionized water , filtered, washed with distilled water, dried and pulverized at 100°C to obtain polyimide, the obtained polyimide molecular formula is:

[0028]

[0029] In the specific operation, the diamine can also use 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, or m-phenylenediamine, and the polyimide obtained by using them as diamine The molecular formula is as follows:

[0030]

Embodiment 2

[0032] The raw material components are by weight: 1 part of polyimide obtained in Example 1, 1 part of phenolic mixture (obtained by mixing resorcinol and formaldehyde in a molar ratio of 1:2), a total of 97 parts of deionized water, three 0.5 parts of ethylamine, 0.4 parts of sodium carbonate, and 0.1 parts of 4-dimethylaminopyridine, such as figure 1 Shown:

[0033] (a) polyimide is dissolved in triethylamine and 18 parts of deionized water in proportion to make polyimide precursor solution;

[0034] (b) Dissolve the phenolic mixture into 79 parts of deionized water in proportion, add sodium carbonate and react under a constant temperature of 70°C and a 50KHz ultrasonic environment until it becomes a light red transparent hydrogel to complete the reaction;

[0035] (c) Add the polyimide precursor solution prepared in step a to the hydrogel obtained in step b, then slowly add 4-dimethylaminopyridine, react at a constant temperature of 95°C and 100KHz ultrasonic environment, ...

Embodiment 3

[0038] The raw material components are by weight: 1 part of polyimide obtained in Example 1, 4 parts of phenolic mixture (obtained by mixing 1,4 hydroquinone and furfural in a molar ratio of 1:2), a total of 94 parts of deionized water part, 0.5 part of triethylamine, 0.4 part of calcium hydroxide, 0.1 part of 4-dimethylaminopyridine;

[0039] (a) polyimide is dissolved in the deionized water of triethylamine and 18 parts in proportion, makes polyimide precursor solution;

[0040] (b) Proportionally dissolve the phenolic mixture into 76 parts of deionized water, add calcium hydroxide and react under a constant temperature of 70°C and a 50KHz ultrasonic environment until it becomes a light red transparent hydrogel to complete the reaction;

[0041] (c) Add the polyimide precursor solution prepared in step a to the hydrogel obtained in step b, then slowly add 4-dimethylaminopyridine, react at a constant temperature of 95°C and 100KHz ultrasonic environment, and wait until it bec...

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Abstract

The invention discloses a method for preparing polyimide-modified phenolic aerogel. The polyimide modified phenolic aerogel is prepared from the following raw materials in parts by weight: 1 part of polyimide, 1-10 parts of phenol and aldehyde, 85-97 parts of deionized water, 0.5 part of ethylenetriamine, 0.4 part of catalyst A and 0.1 parts of catalyst B. The method comprises the following main steps: preparing a polyimide water-soluble precursor solution firstly; then, preparing phenolic hydrogel; and finally, sequentially carrying out crosslinking, acid pickling and aging on the polyimide water-soluble precursor solution and a network structure in the hydrogel, and carrying out solvent replacement and ambient-pressure drying on the obtained product, so that polyimide-modified phenolic aerogel is obtained finally. The apparent density of the prepared aerogel material is 0.03-0.5 g / cm<3>, the specific surface area is 400-900 m<2> / g, the aperture size of the aerogel is 5-50 nm, the heat conduction coefficient is 0.012-0.025 W / m.k, the temperature resistance range is minus 130-800 DEG C, and the aerogel is good in mechanical and processing properties, excellent in insulating properties, wide in applicable temperature and excellent in thermal insulation performance.

Description

technical field [0001] The invention belongs to the field of foaming materials, and in particular relates to a method for preparing polyimide-modified phenolic airgel. Background technique [0002] Compared with traditional foam materials, airgel has higher specific strength and specific surface area, and its pore size is smaller, uniform, and better in heat and sound insulation, so it has high research value; since its appearance in 1931, it has been mainly divided into There are two types of inorganic aerogels and organic aerogels. Compared with inorganic aerogels, because organic aerogels contain carbon elements, carbon elements have a good ability to absorb heat radiation, especially at high temperatures. Therefore, its high-temperature heat insulation performance is obviously stronger than that of inorganic airgel; the heat insulation performance of phenolic foam is the best among all foams, but its application is limited due to its easy pulverization and slag, and its ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J9/28C08L61/14C08L79/08C08G8/28C08G73/10
Inventor 姚正军姚芮周金堂刘沛江
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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