Preparation method for crosslinking type polyimide aerogel

Abstract

The invention belongs to the technical field of aerogel materials, and particularly relates to a preparation method for a crosslinking type polyimide aerogel. The adopted sol-gel method comprises the steps that acid anhydride and diamine containing a plurality of benzene ring structures are adopted as a precursor body to prepare polyamide acid, then a crosslinking agent is added to form a crosslinking type polyamide acid structure, imidization is performed to form wet gel, and the supercritical drying technology is combined with the wet gel to obtain the crosslinking type polyimide aerogel material with the low mass, high specific surface area and good heat stability. Compared with the prior art, the preparation method has the advantages that raw materials are easy to obtain, the reaction process is simple, the obtained material is of the nanometer level three-dimensional net structure, the density of the material is smaller than 130 mg / cm<3>, the specific surface area can reach more than 500 mg / cm<3>, and the problems that conventional organic aerogel is high in density, low in specific area, poor in heat stability and the like are solved.

Description

technical field

[0001] The invention relates to a preparation method of an airgel, in particular to a preparation method of a cross-linked polyimide airgel, and belongs to the technical field of preparation of nanoporous materials. Background technique

[0002] Aerogels are a class of nanoporous functional materials with hierarchical fractal structures. Due to the combination of macroscopic properties and nano-effects, it exhibits many unique properties and has broad application prospects. Organic aerogels have poor thermal stability, high density, and low specific surface area, which limit their application prospects. Polyimide has good thermal stability, low density, and excellent comprehensive performance. It is often used as a special engineering material and widely used in many fields. Recently, countries are listing the research, development and utilization of polyimide as one of the most promising engineering plastics in the 21st century.

[0003] Chinese patent CN...

Examples

Embodiment 1

[0021] Preparation of cross-linked polyimide airgel

[0022] Diamine, dianhydride and silane coupling agent (2,2'-bis[4-(4-aminophenoxyphenyl)]propane, 3,3',4,4'-biphenyltetracarboxylic acid di Anhydride, 3-aminopropyltriethoxysilane mass ratio is 2.5:3.4:0.15) dissolved in N-methylpyrrolidone, mixed into a 48ml mixed solution, stirred rapidly, then added dehydrating agent 11.1ml (acetic anhydride, The volume ratio of pyridine is 6.5:5.6), and after rapid stirring, it gels at room temperature. After 24 hours, use pure N-methylpyrrolidone for 2 solvent replacements, with an interval of 6-10 hours each time, and then use a mixed solution of N-methylpyrrolidone and acetone for 2 solvent replacements, each time for 6-10 hours. Finally, the gel was replaced with pure acetone for 3 times of solvent, each time for 6-10h, and finally supercritical drying was carried out. The resulting density is 130mg / cm 3 , The specific surface area is 530m 2 / g of cross-linked polyimide airgel. ...

Embodiment 2

[0025] Preparation of cross-linked polyimide airgel

[0026] Diamine, dianhydride and silane coupling agent (2,2'-bis[4-(4-aminophenoxyphenyl)]propane, 3,3',4,4'-biphenyltetracarboxylic acid di Anhydride, 3-aminopropyltriethoxysilane mass ratio is 2.5:3.4:0.15) dissolved in N-methylpyrrolidone, mixed into a 35ml mixed solution, stirred rapidly, then added dehydrating agent 11.1ml (acetic anhydride, The volume ratio of pyridine is 6.5:5.6), and after rapid stirring, it gels at room temperature. After 24 hours, use pure N-methylpyrrolidone for 2 solvent replacements, with an interval of 6-10 hours each time, and then use a mixed solution of N-methylpyrrolidone and acetone for 2 solvent replacements, each time for 6-10 hours. Finally, the gel was replaced with pure acetone for 3 times of solvent, each time for 6-10h, and finally supercritical drying was carried out.

Embodiment 3

[0028] Preparation of cross-linked polyimide airgel

[0029] Diamine, dianhydride and silane coupling agent (2,2'-bis[4-(4-aminophenoxyphenyl)]propane, 3,3',4,4'-biphenyltetracarboxylic acid di Anhydride, 3-aminopropyltriethoxysilane mass ratio is 2.5:3.4:0.15) dissolved in N-methylpyrrolidone, mixed into a 70ml mixed solution, stirred rapidly, then added dehydrating agent 11.1ml (acetic anhydride, The volume ratio of pyridine is 6.5:5.6), and after rapid stirring, it gels at room temperature. After 24 hours, use pure N-methylpyrrolidone for 2 solvent replacements, with an interval of 6-10 hours each time, and then use a mixed solution of N-methylpyrrolidone and acetone for 2 solvent replacements, each time for 6-10 hours. Finally, the gel was replaced with pure acetone for 3 times of solvent, each time for 6-10h, and finally supercritical drying was carried out.

technical field

[0001] The invention relates to a preparation method of an airgel, in particular to a preparation method of a cross-linked polyimide airgel, and belongs to the technical field of preparation of nanoporous materials. Background technique

[0002] Aerogels are a class of nanoporous functional materials with hierarchical fractal structures. Due to the combination of macroscopic properties and nano-effects, it exhibits many unique properties and has broad application prospects. Organic aerogels have poor thermal stability, high density, and low specific surface area, which limit their application prospects. Polyimide has good thermal stability, low density, and excellent comprehensive performance. It is often used as a special engineering material and widely used in many fields. Recently, countries are listing the research, development and utilization of polyimide as one of the most promising engineering plastics in the 21st century.

[0003] Chinese patent CN...

Examples

Embodiment 1

[0021] Preparation of cross-linked polyimide airgel

[0022] Diamine, dianhydride and silane coupling agent (2,2'-bis[4-(4-aminophenoxyphenyl)]propane, 3,3',4,4'-biphenyltetracarboxylic acid di Anhydride, 3-aminopropyltriethoxysilane mass ratio is 2.5:3.4:0.15) dissolved in N-methylpyrrolidone, mixed into a 48ml mixed solution, stirred rapidly, then added dehydrating agent 11.1ml (acetic anhydride, The volume ratio of pyridine is 6.5:5.6), and after rapid stirring, it gels at room temperature. After 24 hours, use pure N-methylpyrrolidone for 2 solvent replacements, with an interval of 6-10 hours each time, and then use a mixed solution of N-methylpyrrolidone and acetone for 2 solvent replacements, each time for 6-10 hours. Finally, the gel was replaced with pure acetone for 3 times of solvent, each time for 6-10h, and finally supercritical drying was carried out. The resulting density is 130mg / cm 3 , The specific surface area is 530m 2 / g of cross-linked polyimide airgel. ...

Embodiment 2

[0025] Preparation of cross-linked polyimide airgel

[0026] Diamine, dianhydride and silane coupling agent (2,2'-bis[4-(4-aminophenoxyphenyl)]propane, 3,3',4,4'-biphenyltetracarboxylic acid di Anhydride, 3-aminopropyltriethoxysilane mass ratio is 2.5:3.4:0.15) dissolved in N-methylpyrrolidone, mixed into a 35ml mixed solution, stirred rapidly, then added dehydrating agent 11.1ml (acetic anhydride, The volume ratio of pyridine is 6.5:5.6), and after rapid stirring, it gels at room temperature. After 24 hours, use pure N-methylpyrrolidone for 2 solvent replacements, with an interval of 6-10 hours each time, and then use a mixed solution of N-methylpyrrolidone and acetone for 2 solvent replacements, each time for 6-10 hours. Finally, the gel was replaced with pure acetone for 3 times of solvent, each time for 6-10h, and finally supercritical drying was carried out.

Embodiment 3

[0028] Preparation of cross-linked polyimide airgel

[0029] Diamine, dianhydride and silane coupling agent (2,2'-bis[4-(4-aminophenoxyphenyl)]propane, 3,3',4,4'-biphenyltetracarboxylic acid di Anhydride, 3-aminopropyltriethoxysilane mass ratio is 2.5:3.4:0.15) dissolved in N-methylpyrrolidone, mixed into a 70ml mixed solution, stirred rapidly, then added dehydrating agent 11.1ml (acetic anhydride, The volume ratio of pyridine is 6.5:5.6), and after rapid stirring, it gels at room temperature. After 24 hours, use pure N-methylpyrrolidone for 2 solvent replacements, with an interval of 6-10 hours each time, and then use a mixed solution of N-methylpyrrolidone and acetone for 2 solvent replacements, each time for 6-10 hours. Finally, the gel was replaced with pure acetone for 3 times of solvent, each time for 6-10h, and finally supercritical drying was carried out.

Images