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Method for preparing polyimide aerogel through direct vacuum drying

A polyamic acid wet gel and vacuum drying technology, applied in the field of high-performance porous material preparation, can solve the problems of low efficiency and high cost, and achieve the effects of good replacement effect, low solvent amount and excellent thermal stability.

Inactive Publication Date: 2016-06-15
成都正威新材料研发有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to overcome the defects of high cost and low efficiency caused by high boiling point solvents and complex supercritical drying or freeze drying processes in the preparation of polyimide airgel in the prior art, the present invention provides a direct vacuum drying Method for preparing polyimide airgel

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The pyromellitic anhydride was dried in an oven at 200 °C for 2 hours to remove moisture. Fully dissolve 7.089g of 4,4'-diaminodiphenylmethane in a low-boiling mixed solvent composed of 68g of tetrahydrofuran and 17g of methanol, then add 7.8575g of dried pyromellitic anhydride monomer, and stir at room temperature for 4 hours. Pour it into a mold and let it stand for 1 day to obtain a polyamic acid wet gel. Then use acetone as the replacement solvent, and replace the acetone every 12 hours. After the replacement for 1 day, use tert-butanol as the replacement solvent, replace the acetone, and also replace it every 12 hours. After the replacement for 2 days, dry it in vacuum at room temperature to obtain polyamic acid gas. gel. Then, the polyamic acid airgel was subjected to high-temperature imidization by a temperature programming process of 100°C for 2 hours, 150°C for 2 hours, and 250°C for 2 hours to obtain block polyimide airgel. The density of gained polyimide ai...

Embodiment 2

[0028] The pyromellitic anhydride was dried in an oven at 200 °C for 2 hours to remove moisture. Fully dissolve 7.089g of 4,4'-diaminodiphenylmethane in a low-boiling mixed solvent composed of 68g of tetrahydrofuran and 17g of methanol, then add 7.8575g of dried pyromellitic anhydride monomer, and stir at room temperature for 4 hours. Pour it into the mold and let it stand for 2 days to obtain polyamic acid wet gel, then use acetone as the replacement solvent, replace the acetone every 12 hours, after 1 day of replacement, use tert-butanol as the replacement solvent, replace the acetone, also every 12 hours Replace it once, and after 2 days of replacement, dry it in vacuum at room temperature to obtain polyamic acid airgel, and then use the temperature programming process of 100°C for 2 hours, 150°C for 2h, and 250°C for 2 hours to perform high-temperature imide on the polyamic acid airgel. into block polyimide airgel. The density of gained polyimide airgel is 0.091g / cm 3 , ...

Embodiment 3

[0030] The pyromellitic anhydride was dried in an oven at 200 °C for 2 hours to remove moisture. Fully dissolve 7.089g of 4,4'-diaminodiphenylmethane in a low-boiling mixed solvent composed of 68g of tetrahydrofuran and 17g of methanol, then add 7.8575g of dried pyromellitic anhydride monomer, and stir at room temperature for 4 hours. Pour it into the mold and let it stand for 3 days to obtain polyamic acid wet gel, then use acetone as the replacement solvent, replace the acetone every 12 hours, after 1 day of replacement, use tert-butanol as the replacement solvent, replace the acetone, also every 12 hours Replace it once, and after 2 days of replacement, dry it in vacuum at room temperature to obtain polyamic acid airgel, and then use the temperature programming process of 100°C for 2 hours, 150°C for 2h, and 250°C for 2 hours to perform high-temperature imide on the polyamic acid airgel. into block polyimide airgel. The density of gained polyimide airgel is 0.083g / cm 3 , ...

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Abstract

The invention provides a method for directly vacuum drying and preparing polyimide airgel. The invention adopts the low boiling point solvent to replace the traditional high boiling point solvent, which can be effectively removed in the preparation of the polyimide airgel, and the replaced solvent can be used repeatedly. In addition, a solvent with a high freezing point is used to replace a solvent with a low boiling point. During the vacuum drying process, the solvent is directly sublimated from the solid phase to the gas phase, which avoids the gas-liquid interface and eliminates the capillary tension. The obtained product maintains the pore structure without collapsing. Compared with supercritical drying or freeze-drying process, this method has the advantages of simple operation, high efficiency and low energy consumption, and can be prepared on a large scale, and the obtained polyimide airgel has excellent performance, especially excellent heat insulation performance, and can be used as Insulation material is used.

Description

technical field [0001] The invention relates to a method for preparing polyimide airgel, in particular to a method for directly vacuum drying and preparing polyimide airgel, and belongs to the technical field of preparation of high-performance porous materials. Background technique [0002] Airgel is a kind of dry gel material whose dispersion medium is air. Airgel contains a large amount of air, its solid phase and pore structure are at the nanometer level, and the porosity is above 80%. This structure not only makes airgel the solid material with the smallest density in the world, but also makes airgel show its unique properties in mechanics, acoustics, heat, optics and other aspects. Its fine nanostructure makes the thermal conductivity of the material Very low, and has excellent acoustic impedance and sound insulation performance. [0003] Aerogels can be divided into inorganic and organic polymer aerogels according to their chemical composition. Inorganic airgel mate...

Claims

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Application Information

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IPC IPC(8): C08J9/28C08J3/09C08L79/08C08G73/10
CPCC08J9/28C08G73/1007C08G73/1067C08J3/09C08J2379/08C08L79/08C08L2201/08
Inventor 王建英黄渝鸿朱勇李晓敏程四龙裴星崎姚曾
Owner 成都正威新材料研发有限公司
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