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A preparation method of polyimide nanofiber airgel with controllable microstructure

A nanofiber and polyimide technology, which is applied in the field of polyimide nanofiber airgel preparation, can solve the problems of easy rupture, complicated process, and difficult forming and processing of airgel

Active Publication Date: 2021-10-22
TECH & ENG CENT FOR SPACE UTILIZATION CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The supercritical method directly affects the composition and structure of the three-dimensional network of the gel through the sol-gelation process of the precursor, which determines the performance and function of the material to a large extent. Although the thermal conductivity of the nano-network with high cross-linking density It is greatly reduced, but it is not conducive to stress dispersion. In addition, the rigid and brittle characteristics of inorganic materials make this type of airgel difficult to form and process, and it is easy to break during use.
However, the method of adjusting the microscopic spatial distribution of materials mainly relies on the method of chemical synthesis, which is a complicated process.

Method used

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  • A preparation method of polyimide nanofiber airgel with controllable microstructure
  • A preparation method of polyimide nanofiber airgel with controllable microstructure
  • A preparation method of polyimide nanofiber airgel with controllable microstructure

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Experimental program
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Effect test

Embodiment 1

[0034] Step 1: After shearing 100 mg of polyimide, place it in 25 ml of solvent for ultrasonic dispersion to obtain a homogeneous nanofiber dispersion solution; the time for the ultrasonic dispersion is 0.5 hours, and the solvent is 1,4-dioxane .

[0035] Step 2: Freezing and crystallizing the nanofiber dispersion solution to produce a microstructure to obtain a crystalline phase of the nanofiber dispersion solution; in the freezing crystallization process, the nanofiber dispersion solution is placed in an environment with a temperature gradient to obtain a temperature gradient Gradient samples are then subjected to freeze crystallization to obtain the crystalline phase of the nanofiber dispersion solution. The temperature range of the temperature gradient is 4°C, the temperature gradient is 2°C / cm, and the time for placing in the temperature gradient environment is 30 minutes; the temperature of the frozen crystallization is -120°C, and the temperature of the frozen crystalli...

Embodiment 2

[0039] Step 1: After shearing 200 mg of polyimide, place it in 25 ml of solvent for ultrasonic dispersion to obtain a homogeneous nanofiber dispersion solution; the time for the ultrasonic dispersion is 3 hours, and the solvent is 1,4-dioxane .

[0040]Step 2: Freezing and crystallizing the nanofiber dispersion solution to produce a microstructure to obtain a crystalline phase of the nanofiber dispersion solution; in the freezing crystallization process, the nanofiber dispersion solution is placed in an environment with a temperature gradient to obtain a temperature gradient Gradient samples are then subjected to freeze crystallization to obtain the crystalline phase of the nanofiber dispersion solution. The temperature range of the temperature gradient is 20°C, the temperature gradient is 2°C / cm, and the time for placing in the environment with a temperature gradient is 1h; the temperature of the frozen crystallization is 10°C, and the time for the frozen crystallization for...

Embodiment 3

[0044] Step 1: After shearing 360 mg of polyimide, place it in 25 ml of solvent for ultrasonic dispersion to obtain a homogeneous nanofiber dispersion solution; the time for the ultrasonic dispersion is 0.5 hours, and the solvent is 1,4-dioxane .

[0045] Step 2: Freezing and crystallizing the nanofiber dispersion solution to produce a microstructure to obtain a crystalline phase of the nanofiber dispersion solution; the freezing crystallization process is the first freeze crystallization of the nanofiber dispersion solution to obtain a frozen sample , and then placing the frozen sample in an environment with a temperature gradient to obtain a temperature gradient sample, and then subjecting the temperature gradient sample to a second freezing crystallization to obtain the crystalline phase of the nanofiber dispersion solution; the second The temperature of the first freezing and crystallization is -120°C, and the time for the first freezing and crystallization is 0.5h; the te...

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Abstract

The invention relates to a preparation method of polyimide nanofiber airgel with controllable microstructure, which is characterized in that it comprises the following steps: step 1: making polyimide into nanofiber dispersion solution; step 2: preparing The nanofiber dispersion solution is subjected to freeze crystallization to produce a microstructure to obtain a crystalline phase of the nanofiber dispersion solution; Step 3: remove the ice crystals of the nanofiber dispersion solution crystalline phase to obtain an uncrosslinked nanofiber skeleton; Step 4: The uncrosslinked nanofiber skeleton is heated to stabilize the configuration, resulting in a polyimide nanofiber airgel. By controlling the freezing speed and temperature gradient, the solvent freezing nucleation is directional controlled, thereby controlling the skeleton construction of polyimide nanofibers and determining the macroscopic functional properties of the material. Compared with the traditional method, the method is simple, convenient to control process parameters, and can improve operation efficiency and product success rate.

Description

technical field [0001] The invention relates to the field of new materials and new techniques, in particular to a preparation method of polyimide nanofiber airgel with controllable microstructure. Background technique [0002] At present, the technology of preparing polyimide nanofiber airgel is mainly based on supercritical method. The supercritical method directly affects the composition and structure of the three-dimensional network of the gel through the sol-gelation process of the precursor, which determines the performance and function of the material to a large extent. Although the thermal conductivity of the nano-network with high cross-linking density It is greatly reduced, but it is not conducive to stress dispersion. In addition, the rigid and brittle characteristics of inorganic materials make this type of airgel difficult to form and process, and it is easy to break during use. The method of controlling the microscopic spatial distribution of materials mainly r...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J9/28C08L79/08
CPCC08J9/28C08J2201/0482C08J2379/08
Inventor 赵海峰袁子豪盛强赵宁钱振超
Owner TECH & ENG CENT FOR SPACE UTILIZATION CHINESE ACAD OF SCI