Preparation method of polyimide nanofiber aerogel with controllable microstructure

A nanofiber and polyimide technology is applied in the field of preparation of polyimide nanofiber aerogel, which can solve the problems of difficult forming and processing of aerogel, complicated method and process, easy to break, etc., and can overcome low mechanical strength. , Improve the operation efficiency, the effect of the method is simple

Active Publication Date: 2020-08-14
TECH & ENG CENT FOR SPACE UTILIZATION CHINESE ACAD OF SCI
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  • Summary
  • Abstract
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  • Application Information

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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...

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  • Preparation method of polyimide nanofiber aerogel with controllable microstructure
  • Preparation method of polyimide nanofiber aerogel with controllable microstructure
  • Preparation method of polyimide nanofiber aerogel with controllable microstructure

Examples

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 aerogel with a controllable microstructure. The preparation method is characterized by comprising the following steps: step 1, preparing polyimide into a nanofiber dispersion solution; step 2, carrying out freezing crystallization on the nanofiber dispersion solution to manufacture a micro-configuration so as to obtain a nanofiber dispersion solution crystalline phase; step 3, removing ice crystals of the crystalline phase of the nanofiber dispersion solution to obtain an uncrosslinked nanofiber skeleton; and step 4, heatingthe non-crosslinked nanofiber skeleton to stabilize the configuration, thereby obtaining the polyimide nanofiber aerogel. The freezing nucleation of the solvent is directionally controlled by controlling the freezing speed and the temperature gradient so that the framework construction of the polyimide nanofiber is controlled, and the macroscopic functional characteristics of the material are determined. Compared with a traditional method, the method is simple and convenient and convenient to control technological parameters, and the operation efficiency and the product success rate can be improved.

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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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
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