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Chemical crosslinking polyimide aerogel and preparation method thereof

A chemical cross-linking and polyimide technology, applied in the field of materials, can solve the problems affecting the quality of polyimide airgel products, the inability to cross-link polyamine monomers, and the low strength of the airgel skeleton, and achieve freezing Drying is simple and easy, equipment requirements are low, and the effect of reducing dimensional shrinkage

Pending Publication Date: 2020-09-11
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the greater flexibility of polyamic acid molecular chains, the strength of its airgel skeleton is low, resulting in a large shrinkage of polyamic acid airgel size, which seriously affects the quality of polyimide airgel products.
Generally speaking, the introduction of chemical cross-linking structure is an effective means of polymer reinforcement, but due to the low activity of carboxylate groups on the molecular chain of polyamic acid, it is impossible to further cross-link with polyamine monomers in aqueous solution, and after chemical cross-linking The polyamic acid is also difficult to dissolve in water under the action of tertiary amines, which limits the application of chemical crosslinking in the preparation of polyimide airgel by freeze-drying method to a certain extent.

Method used

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  • Chemical crosslinking polyimide aerogel and preparation method thereof
  • Chemical crosslinking polyimide aerogel and preparation method thereof
  • Chemical crosslinking polyimide aerogel and preparation method thereof

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preparation example Construction

[0025] A kind of preparation method of chemically cross-linked polyimide airgel of the present invention specifically comprises the following steps:

[0026] Firstly, reacting diamine monomers, dianhydride monomers, polyamine monomers, tertiary amines, and alkyl ammonium halides in an aqueous solution to prepare a chemically crosslinked polyamic acid hydrogel.

[0027] The specific means are as follows: ultrasonically treat single-necked flasks, beakers, molds, magnets, etc. with absolute ethanol to remove surface impurities, and dry them for later use. Put the weighed diamine monomer, polyamine monomer, tertiary amine, and alkyl ammonium halide into a single-necked flask with a magnet, add deionized water, stir at room temperature or under ice-water bath conditions until a uniform solution is formed, and then Add the dianhydride monomer and stir for 24-48 hours at room temperature or in an ice-water bath to form a viscous liquid, that is, a chemically cross-linked polyamic ac...

Embodiment 1

[0040] Preparation of chemically cross-linked polyimide airgel: first, 2.00g 4,4'-diaminodiphenyl ether (ODA), 0.06g 2,4,6-triaminopyrimidine, 0.1mL triethylamine 1. Add 0.1g of dodecyltrimethylammonium chloride into 50mL of deionized water, stir in an ice-water bath until a homogeneous solution is formed, add 2.18g of pyromellitic anhydride (PMDA) and continue stirring for 24h to obtain a viscous liquid. That is, chemically cross-linked polyamic acid hydrogel; secondly, pour the hydrogel into the mold, and refrigerate for 48 hours after vacuum degassing, and then freeze and freeze-dry the chemically cross-linked polyamic acid airgel ; Finally, the obtained polyamic acid airgel is thermally imidized to obtain a chemically cross-linked polyimide airgel. The thermal imidization process is: 120°C (0.5h)+150°C (0.5h)+ 200°C (0.5h) + 250°C (0.5h) + 300°C (0.5h) + 350°C (2h).

Embodiment 2

[0042] Preparation of chemically cross-linked polyimide airgel: first, 1.90g 4,4'-diaminodiphenyl ether (ODA), 0.06g 2,4,6-triaminopyrimidine, 0.1mL triethylamine 1. Add 0.1g of dodecyltrimethylammonium chloride into 50mL of deionized water, stir in an ice-water bath until a homogeneous solution is formed, add 2.18g of pyromellitic anhydride (PMDA) and continue stirring for 24h to obtain a viscous liquid. That is, chemically cross-linked polyamic acid hydrogel; secondly, pour the hydrogel into the mold, and refrigerate for 48 hours after vacuum degassing, and then freeze and freeze-dry the chemically cross-linked polyamic acid airgel ; Finally, the obtained polyamic acid airgel is thermally imidized to obtain a chemically cross-linked polyimide airgel. The thermal imidization process is: 120°C (2h) + 150°C (2h) + 200°C (2h)+250°C (2h)+300°C (2h)+350°C (0.5h).

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Abstract

The invention discloses a chemical crosslinking type polyimide aerogel and a preparation method thereof, and belongs to the technical field of materials. According to the invention, a chemical crosslinking type polyamide acid hydrogel is prepared under the action of an auxiliary agent and a surfactant in an aqueous solution system; freeze drying and thermal imidization are carried out, so that thechemical crosslinking type polyimide aerogel is obtained; the method has the advantages of being simple, efficient, low in equipment requirement, wide in application range and environmentally friendly; the problem that traditional polyimide high-performance aerogel is difficult to prepare can be effectively avoided, and the obtained aerogel can be used for gas adsorption, organic matter adsorption, heat preservation materials and the like and has high potential application value in the fields of air pollution treatment, water pollution treatment, heat preservation structural materials and thelike.

Description

technical field [0001] The invention belongs to the technical field of materials and relates to the preparation of polymer airgel, in particular to a chemically cross-linked polyimide airgel and a preparation method thereof. Background technique [0002] Airgel is a highly dispersed solid material, mainly composed of a nanoporous network structure filled with a gaseous dispersion medium in the pores obtained by the aggregation of colloidal particles (or polymer molecules). Three-dimensional porous nanomaterials in which the liquid component is replaced by a gas while still maintaining its gel network. The special continuous three-dimensional network structure makes airgel show unique properties in thermal, mechanical, acoustic, optical, electrical, etc. and other fields have received much attention. [0003] Polyimide refers to a class of polymers containing imide rings in the molecular main chain structural unit, which has outstanding thermo-oxidative stability, dielectri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/28C08J3/24C08L79/08
CPCC08J9/28C08J3/24C08J2379/08C08J2205/026C08J2201/0484
Inventor 卓龙海谢璠蔡亚玲陈珊珊沈东
Owner SHAANXI UNIV OF SCI & TECH
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