Structure design of non-woven fabric absorbing material
With the rapid development of the modern electronics industry, non-woven fabric absorbing materials have entered the era of electronic information, and more and more electronic and electrical equipment have entered all corners of the society, but these electronic and electrical equipment will produce A certain electromagnetic wave will not only cause a certain electromagnetic interference to the surrounding electronic and electrical equipment, but also a certain electromagnetic radiation hazard to the human body. In order to effectively suppress electromagnetic interference and electromagnetic radiation hazards, the research of non-woven fabric absorbing materials is particularly important. The Yachi Industrial team has been committed to the development of high-efficiency electromagnetic shielding materials, and has made a series of progress in the preparation and performance research of graphene-based non-woven fabric absorbing materials.
(1) Researchers designed a high-strength flexible polymer/graphene composite film with a sandwich structure and explored the effect of the zigzag folding structure on the electromagnetic shielding of the film. The high-strength flexible polymer/graphene composite film is prepared by using ordinary non-woven fabric absorbing materials as the reinforced interlayer and polymer/graphene composite as the conductive coating. Electromagnetic shielding test results show that zigzag folding of film samples can enhance its electromagnetic shielding performance (especially for films with higher conductivity). The smaller serration angle and longer serration edge length make the zigzag folding pair The enhancement of thin-film electromagnetic shielding is more obvious. This is mainly because the smaller serration angle and longer serration side length can make a larger area of material participate in electromagnetic shielding, and at the same time enhance the multiple reflection and attenuation of electromagnetic waves by the serration. At the same time, the effective control of the electromagnetic shielding performance of the film can be achieved by simply stretching or compressing the zigzag structure.
(2) Researchers of Yachi Industry explored the influence of multilayer composite structure (gradient structure + hollow sandwich structure) on the electromagnetic shielding performance of polymer/graphene composites. First, by freely stacking and combining polymer/graphene composite foams with different graphene content, composite materials with different gradient structures can be prepared. The results show that: ①The gradient structure has little effect on the electromagnetic shielding performance of the composite material, but it can Significantly increase the wave impedance between the composite material and the air, thereby enhancing the electromagnetic wave absorption performance; ②The structural design with the strongest wave absorption performance is the abc structure, and the structural design with the strongest electromagnetic wave reflection is the cba structure. In addition, a composite material with a hollow sandwich structure can be obtained by sandwiching the wave-transmitting material between two layers of polymer/graphene composite foam. The results show that: ① The hollow sandwich structure can greatly improve the shielding performance of the composite material, but the main reason is It enhances the reflection of electromagnetic waves by the material; ②The increase in the shielding effectiveness of the sandwich structure to the composite material is related to the thickness of the middle wave-transmitting layer. When the thickness is 1/4 wavelength of the corresponding frequency band, the increase is the largest. This research has great reference value for the design of polymer-based electromagnetic shielding materials with high shielding and wave-absorbing properties.