Preparation method of polyimide nanofiber aerogel with controllable microstructure

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...

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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 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.

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