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A Gradient Impedance Graphene-Based Polyimide Composite Foam Absorbing Material

A technology of alkenyl polyimide and graphene foam, which is applied in the field of porous microwave-absorbing materials and its preparation, can solve problems such as surface impedance mismatch, narrow frequency bandwidth, and weak microwave absorption strength, and achieve improved surface impedance matching, The effect of enhancing the secondary absorption and enhancing the microwave absorption intensity

Active Publication Date: 2021-11-16
JIANGNAN UNIV
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  • Claims
  • Application Information

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Problems solved by technology

[0006] In order to solve the above problems, the present invention provides a three-stage impedance gradient graphene-based polyimide composite foam absorbing material and its preparation method, the purpose of which is to overcome the microwave absorption caused by the mismatch of surface impedance of existing carbon foam materials. Disadvantages such as weak strength and narrow frequency bandwidth

Method used

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  • A Gradient Impedance Graphene-Based Polyimide Composite Foam Absorbing Material
  • A Gradient Impedance Graphene-Based Polyimide Composite Foam Absorbing Material
  • A Gradient Impedance Graphene-Based Polyimide Composite Foam Absorbing Material

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Embodiment 1

[0044] (1) prepare first-grade graphene foam:

[0045] Preparation of graphene oxide: Add 2g of 325 mesh flake graphite, 240mL of concentrated sulfuric acid and 27mL of concentrated phosphoric acid into a 500mL three-necked flask, mechanically stir for 30min, then slowly add 12g of potassium permanganate, control the temperature in a water bath at 50°C, and continue stirring at a constant speed for 12h. After the reaction, the mixture was slowly poured into a beaker containing 400 mL of deionized water, and stirred evenly with a glass rod. A 30% hydrogen peroxide aqueous solution was added dropwise to the mixture, and stirred until the solution turned golden yellow, and stood overnight. Centrifuge the mixed solution to remove a large amount of acid and metal ions remaining in the mixed solution; then wash with 5% HCl solution and deionized water for several times until the pH value is close to 5-6. The obtained graphene oxide is freeze-dried for later use.

[0046] Preparati...

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Abstract

The invention discloses a graphene-based polyimide composite foam wave-absorbing material with gradient impedance, and belongs to the technical field of porous wave-absorbing materials and their preparation. Among them, the low-impedance skeleton structure is a porous foam material obtained by in-situ self-assembly of graphene oxide; the secondary structure is a graphene / polyimide composite material with high impedance characteristics; the tertiary structure is a polyimide composite material with high impedance characteristics Polyimide material. Follow the steps below: 1. In situ self-assembled graphene porous composite foam material; 2. Graphene foam adopts vacuum impregnation method to load the middle layer of graphene / polyimide composite material; 3. Continue to use the same vacuum impregnation method to load Polyimide material layer. The three-stage impedance gradient composite foam material prepared by the present invention exhibits excellent absorbing strength and absorbing bandwidth, the preparation process is simple and easy to operate, and is green and environmentally friendly. It is expected to be used in aerospace, military equipment, and civilian electrical appliances that have requirements for electromagnetic wave absorption. field.

Description

technical field [0001] The invention relates to a graphene-based polyimide composite foam wave-absorbing material with gradient impedance, and belongs to the technical field of porous wave-absorbing materials and their preparation. Background technique [0002] As a functional material that effectively attenuates incident electromagnetic waves by means of dielectric loss, magnetic loss, or conductance loss, microwave absorbing materials have gained widespread attention in the field of electromagnetic protection. Traditional ferrite, carbonyl iron, and ceramics exhibit excellent microwave absorption properties. However, their disadvantages such as high density, easy corrosion, and high cost limit their further application in the field of microwave absorption. In recent years, carbon foam material, as a porous material with a three-dimensional conductive network structure inside, is gradually becoming a very competitive microwave absorbing material due to its light weight, co...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J9/42C08J9/40C08J9/28C08L79/08C08K3/04C08K7/24
CPCC08J9/28C08J9/40C08J9/42C08J2201/0484C08J2379/08C08J2479/08C08K7/24C08K2201/001C08K2201/005C08K3/042
Inventor 王子成刘天西李双双张亚伟
Owner JIANGNAN UNIV
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