The Research Of Carbon Black/Carbon Fiber With Epoxy Composite Absorbing Material

With the rapid development of the information society and the great popularity of electronic machine and the higher CPU speed, the pollution of high frequency electromagnetic wave radiation is also more and more serious. The protection of electromagnetic environment and the technology of electromagnetic compatibility has become a rapid development of the important fields. The absorbing material is the key technology to eliminate the electromagnetic radiation pollution and realize the military stealth, which has become one of the hot spot of scientific research at home and abroad.The absorbing material what we need should have wide frequency band absorption, light quality, good absorption, thinner thickness, better physical performance and easier to use etc.Based on the electromagnetic wave absorption theory and transmission line theory, this paper researches the affection of dielectric constant, thickness and electromagnetic wave frequency on absorption properties by plate reflecting type. According to a large number of experiments on the carbon black, carbon fiber composite with epoxy resin, and improving the theory, this paper aims to design and preparation of high-performance electromagnetic absorption material.Studies show that, for carbon fiber-epoxy resin composite material, fiber length has great influence on the material absorption performance, the longer the fiber the absorption the worse. Absorbing effect is good in a certain range when the length is1-2mm. With the increase of the content of fiber, composite materials of the equivalent dielectric constant real part of the imaginary part present the first increases, then decreases trend. When content was invariable, dielectric constant real part imaginary part on frequency revealed a different change with the increase of fiber content, absorbing peak first increases, then decreases. The position of the absorption peaks increases with the content gradually moves to the low frequency.The change of the dielectric constant of carbon black-resin composite material is similar with the carbon fiber-epoxy resin composite material. With the increase of the content of carbon black, the absorption of material presents first increased and then decreased. The position of the absorption peaks increase with the content of carbon black, moving to the low frequency.Research shows that the different content of carbon black and carbon fiber can realize modulation of the material complex dielectric constant, but it is hard to achieve high bandwidth absorption by controlling their content. In this paper we adjust the composite material complex dielectric constant according to the multi-layer structure. Through multi-layered compound modulation, a new kind of composite materials complex with dielectric constant, s=6.1-3j, near dielectric constant of no reflection curve can be achieved.According to the design, we successfully worked out the thickness of2.8mm, light absorption coating with X wide. For indoor electromagnetic pollution, was successfully achieved the fiber modulation film which length is5mm and content is0.4%-0.5%was successfully fabricated, after compounded with plasterboard it achieved good absorption in S-band, and the thickness of the material was reduced.The design ideas in this paper laid the foundations for the preparation of electromagnetic wave absorbing materials, which has both important practical value and theoretical significance.