Flexible polyimide aerogel and preparation method thereof

Abstract

The invention discloses flexible polyimide aerogel which is prepared by the following method: (1) reacting a dianhydride monomer, an isocyanate monomer and a polyether polyol monomer in a polar aprotic organic solvent to form flexible polyamide acid; (2) putting flexible polyamide acid into acetone for replacement to obtain a semi-finished product; (3) performing supercritical CO2 drying on the semi-finished product to obtain polyamide acid aerogel; and (4) carrying out post-curing on the polyamide acid aerogel to obtain the polyimide aerogel. According to the flexible polyimide aerogel, the polyether polyol is used as a flexible long chain, the polyamide acid precursor is prepared by combining an isocyanate monomer and a dianhydride monomer to form flexible polyimide through reaction withdiamine,and a supercritical CO2 drying method is adopted to prepare the polyurethane-modified flexible polyimide, such that the polyurethane-modified flexible polyimide has advantages of polyurethane modification, excellent shock absorption, excellent noise reduction, excellent thermal insulation and excellent dimensional stability, and has broad application prospects especially in the field ofapplications requiring impact resistance.

Description

technical field [0001] The invention relates to a flexible polyimide airgel and a preparation method thereof, belonging to the technical field of polymer porous materials. Background technique [0002] Polyimide is a kind of organic polymer material with imide ring in the main chain. It has good mechanical strength, heat resistance and heat insulation stability, and anti-friction and anti-wear properties. It is usually used as a high-performance heat-resistant structural part in Many high-end application fields have been applied. Due to the wide selectivity of polyimide raw materials dianhydride and diamine, polyimide materials with specific properties can be synthesized according to specific conditions of use. [0003] Airgel is a solid form of matter and is one of the least dense solids in the world. Because of its excellent lightweight characteristics and heat insulation effect, airgel has been applied in special clothing industry and combat vehicles. At present, the t...

AI Technical Summary

Problems solved by technology

Chinese invention patent application CN 108794766 A discloses a cross-linked polyimide airgel and its preparation method. The intermediate product is obtained by cross-linking the amino-terminated polyamic acid and the polyanhydride-based cross-linking agent. Solvent thermal imidization to obtain polyimide wet gel, which is then obtained by solvent replacement and supercritical drying; the intermediate product is a polyamic acid wet gel with a cross-linked structure; the invention prepares a wet gel with a cross-linked The intermediate product (polyamic acid wet gel) of the network is imidized by solvothermal to convert it into a cross-linked polyimide wet gel, which overcomes the inability to obtain a real cross-linked structure in the prior art. The problem of polyimide airgel

The polyimide prepared by the method of diamine and dianhydride can make the polyimide airgel have good mechanical strength, excellent specific surface area and low density due to the rigid structure of the monomer itself, but the polyimide airgel has excellent specific surface area and low density. Imide itself still lacks toughness, and its effect is not obvious in the application field of receiving relatively large impact force or shock absorption and noise reduction

[0005] Therefore, how to find a reasonable preparation method to obtain a flexible polyimide airgel, overcome the defect of polyimide airgel lack of toughness, and maintain good mechanical strength, specific surface area and low density , has become one of the focuses of many applied researchers in the industry

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