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Cross-linked polyimide aerogel preparation method

A technology of polyimide and airgel, which is applied in the field of preparation of cross-linked polyimide airgel, can solve the problems of poor mechanical properties, obvious shrinkage, high industrial production cost, etc., and achieves low cost and efficient method Simple, low shrinkage effect

Inactive Publication Date: 2017-11-10
LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The invention overcomes the shortcomings of obvious shrinkage, poor mechanical properties and high industrial production cost in the existing preparation technology of polyimide airgel, and provides a preparation method of cross-linked polyimide airgel

Method used

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  • Cross-linked polyimide aerogel preparation method
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Examples

Experimental program
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Embodiment 1

[0024] Dissolve biphenyltetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether (dianhydride: diamine = 1mmol: 0.81mmol) in 12g of NMP and react at low temperature for 12 hours to prepare viscous polyamic acid ( PAA) solution, then add 0.12mmol of melamine crosslinking agent, continue to stir at low temperature for 12h, add 14.49g of dehydrating agent (pyridine: acetic anhydride = 6.33:8.16), stir rapidly and then gel at room temperature. After 24 hours, the mixed solution of NMP and acetone was used to replace the solution three times, each time for 8-24 hours. Then use pure acetone to replace the solvent for 3 times, each time for 8-24 hours, and finally perform supercritical drying to obtain a polyimide airgel membrane material or a monolithic material. The porosity of the obtained ordered polyimide airgel is 84%, and the BET specific surface area is 337m 2 / g, the density is 0.22g / cm 3 , the compressive strength (25%) is 32MPa, and the thermal decomposition temperatur...

Embodiment 2

[0026] Dissolve biphenyltetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether (dianhydride: diamine = 1 mmol: 0.90 mmol) in 13.1 g of NMP and react at low temperature for 12 hours, then add 0.06 mmol of melamine The mixture was continuously stirred at low temperature for 12 h to obtain a viscous PAA solution, and 14.49 g of dehydrating agent (pyridine: acetic anhydride = 6.33 : 8.16) was added, and after rapid stirring, it was allowed to gel at room temperature. After 24 h, the solution was replaced three times with a mixed solution of NMP and acetone, each time for 8-24 h. The gel is then replaced with pure acetone for 3 times of solvent, each time for 8-24 hours, and finally supercritically dried to obtain a polyimide airgel membrane material or a monolithic material. The porosity of the obtained polyimide airgel is 76%, and the BET specific surface area is 281m 2 / g with a density of 0.27g / cm 3 , and the tensile strength is 11.8 MPa.

Embodiment 3

[0028] Dissolve biphenyltetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether (dianhydride: diamine = 1 mmol: 0.93 mmol) in 13.4 g of NMP and react at low temperature for 12 hours to prepare a viscous PAA solution. Then add 0.04mmol of melamine cross-linking agent, continue to stir at low temperature for 12h, add 14.49g of dehydrating agent (pyridine: acetic anhydride = 6.33: 8.16), stir rapidly until it gels at room temperature. After 24 hours, the mixed solution of NMP and acetone was used to replace the solution three times, each time for 8-24 hours. The gel is then replaced with pure acetone for 3 times of solvent, each time for 8-24 hours, and finally supercritically dried to obtain the polyimide airgel monolithic material. Nitrogen adsorption and desorption test The porosity of polyimide airgel is 61%, and the BET specific surface area is 230m 2 / g, the density is 0.31g / cm 3 .

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Abstract

The present invention discloses a cross-linked polyimide aerogel preparation method. According to the present invention, the cross-linked polyimide aerogel prepared by using melamine as a cross-linking agent has advantages of high specific surface area, strong mechanical property and low shrinkage, wherein the mass production cost is reduced; and the prepared cross-linked polyimide aerogel has advantages of low shrinkage (less than 5%), high specific surface area (337 m<2> / g), good mechanical strength (25% compressive strength of 32 MPa), and high thermal stability (Td is more than 571 DEG C).

Description

technical field [0001] The invention relates to a preparation method of cross-linked polyimide airgel. Background technique [0002] Aerogels have attracted extensive attention due to their low density, high porosity, and specific surface area. Among them, the pore size distribution of most aerogels is between 2-50nm, which is lower than the mean free path of air molecules (60-70nm) under normal temperature and pressure conditions, and belongs to the mesoporous category. This feature endows the airgel with a low thermal conductivity. Compared with traditional foam materials, aerogels are used in thermal insulation devices with obvious advantages. Polyimide materials are widely used in high-tech fields such as aerospace and microelectronics due to their superior mechanical properties, dimensional stability, and solvent resistance. Polyimide airgel materials not only have the characteristics of low density, large specific surface area, high specific mechanical properties, a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G73/10C08J3/24C08J3/075C08L79/08
CPCC08G73/1071C08J3/075C08J3/24C08J2379/08
Inventor 王廷梅段春俭王齐华杨增辉谢海
Owner LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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