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Preparation method of chopped fiber layered reinforced polyimide aerogel

A polyimide wet gel, layered reinforcement technology, applied in the direction of fiber type, fiber treatment, textile and papermaking, etc., can solve the problem of poor adhesion, chopped fiber reinforced polyimide aerogel composite material preparation Difficulties and other problems, to achieve excellent shock absorption and noise reduction, enhanced crack resistance performance, and good stability

Active Publication Date: 2021-06-25
NANJING UNIV OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, chopped fiber layered reinforcement is a way to increase the impact resistance of airgel materials while maintaining the thermal insulation properties of airgel materials, but due to the faster gelation speed of polyimide wet gels, short The poor bonding between chopped fibers and airgel matrix makes the preparation of chopped fiber reinforced polyimide airgel composites more difficult, so there has never been a combination of polyimide airgel and short Related reports on layered composite of cut fiber reinforcement

Method used

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  • Preparation method of chopped fiber layered reinforced polyimide aerogel
  • Preparation method of chopped fiber layered reinforced polyimide aerogel

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0033] (1) Dissolve 2.05g of 2,2'-dimethyl-4,4'-diaminobiphenyl (DMBZ) into 95mL of N-methylpyrrolidone (NMP) solvent, and stir at room temperature for 20min Finally, after it was completely dissolved, 2.95g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added, and condensation polymerization was carried out at 25°C for 24 hours to obtain an anhydride group-terminated polyamic acid solution (diphenyl The molar ratio of anhydride monomer to diamine monomer is 1:0.7).

[0034] (2) Soak the chopped fibers in nitric acid for modification at 60°C. The modification time is 2 hours. After taking them out, wash them with ethanol and deionized water successively, and then dry them in a drying oven at a drying temperature of 40°C. Drying time is 6h.

[0035] (3) The polyamic acid solution obtained in step (1) is chemically imidized, and the catalyst pyridine 7mL and the dehydrating agent acetic anhydride 8mL (the molar ratio of pyridine and acetic anhydride to the dianhydr...

example 2

[0040](1) Dissolve 2.10g of 1,4-p-phenylenediamine into a solvent containing 95mL of N,N-dimethylformamide (DMF), stir at room temperature for 20min, then add 2.93g of 3 , 3',4,4'-benzophenonetetraacid dianhydride, carry out condensation polymerization at 25°C for 21h to obtain an anhydride group-terminated polyamic acid solution (the molar ratio of dianhydride monomer to diamine monomer is 1: 0.8).

[0041] (2) Soak chopped fibers in nitric acid for modification at 65°C. The modification time is 2.5 hours. After taking them out, wash them with ethanol and deionized water successively, and then dry them in a drying oven at a drying temperature of 45°C. , drying time is 7h.

[0042] (3) The polyamic acid solution obtained in step (1) is chemically imidized, and the catalyst pyridine 6.6mL and the dehydrating agent acetic anhydride 7.8mL (the molar ratio of pyridine and acetic anhydride to the dianhydride monomer is 8:8.1: 0.8) Add it into the polyamic acid solution, and stir ...

example 3

[0047] (1) Dissolve 2.15g of 4,4'-diaminodiphenyl ether into 95mL of dimethyl sulfoxide (DMSO) solvent, stir at room temperature for 20min, and then add 2.96g of benzene Tetraformic dianhydride was subjected to condensation polymerization reaction at 25° C. for 18 hours to obtain an anhydride group-terminated polyamic acid solution (the molar ratio of dianhydride monomer to diamine monomer was 1:0.9).

[0048] (2) Soak the chopped fibers in nitric acid at 70°C for modification, the modification time is 3 hours, after taking them out, wash them with ethanol and deionized water successively, and then dry them in a drying oven at a drying temperature of 50°C. Drying time is 8h.

[0049] (3) The polyamic acid solution obtained in step (1) is chemically imidized, and the catalyst pyridine 6.2mL and the dehydrating agent acetic anhydride 7.5mL (the molar ratio of pyridine and acetic anhydride to the dianhydride monomer is 8:8.2: 0.9) was added into the polyamic acid solution, and s...

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Abstract

The invention belongs to the field of preparation processes of nano-porous materials, and relates to a preparation method of chopped fiber layered reinforced polyimide aerogel. Modified chopped fibers are used as a reinforcement material, the reinforced chopped fibers are uniformly dispersed in a polyimide aerogel structure in a layered manner, the chopped fibers are used as a skeleton to be inserted in a polyimide aerogel matrix; the fiber addition amount is small, and the fibers are laid in the aerogel matrix in a layered manner, so that a thermal bridge effect generated in heat conduction due to contact between fibers in the direction perpendicular to the fiber layer is avoided, and the heat insulation performance and the compressibility of the aerogel material are not reduced; and because the polyimide aerogel matrix is supported by a crisscross of split-resistant chopped fibers, the crack resistance of the aerogel composite material in the horizontal direction is greatly improved. The density of the prepared fiber layering reinforced polyimide aerogel is 0.09 to 0.12 g / cm<3>, and the thermal conductivity at room temperature is 0.04793 to 0.04859 W / (m*K).

Description

technical field [0001] The invention belongs to the field of preparation technology of nanoporous materials, and relates to a preparation method of chopped fiber layered reinforced polyimide airgel. Background technique [0002] Airgel is a kind of gel material whose dispersion medium is gas. The solid phase and pore structure are on the nanometer scale. It is currently the solid material with the smallest density and the smallest thermal conductivity in the world. Therefore, it has broad application prospects in aerospace lightweight high-temperature-resistant materials, fire-fighting clothing, and satellite surface protection materials. [0003] Polyimide (PI) airgel is a kind of organic polymer airgel containing imide ring in the main chain. Because the main chain contains a heterocyclic structure, it has excellent high and low temperature resistance, and also has Excellent mechanical properties, wear resistance and other excellent properties, so the mechanical propertie...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/28C08L79/08C08L77/10C08L23/12C08K9/02C08K7/14D06M11/64D06M101/36D06M101/20
CPCC08J9/28D06M11/64C08J2379/08C08J2477/10C08J2423/12C08K9/02C08K7/14C08J2205/026D06M2101/36D06M2101/20
Inventor 崔升徐世玉付俊杰王子寒刘学宁袁美玉
Owner NANJING UNIV OF TECH
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