Preparation And Microwave Absorbing Properties Of Reduced Graphene Oxide Composite Materials

Along with the fast development of information technology and wide spread of eletronic products, electromagnetic radiation and electromagnetic interference are becoming serious problems, and much attention has been paid to the preparation of suitable and effective electromagnetic wave absorbers. Here we prepared reduced graphene oxide (r-GO) through chemical method, then the as-prepared r-GO and other two carbon materials, carbon nanotubes (CNTs) and carbon black (CB), were added to the impedance matching layer of three layers microwave absorbing films. The added materials, quantity, and membrane material chloroprene rubber (CR) all play an important role in the film's microwave absorbing property. We also synthesized r-GO/BaTiO₃ and r-GO/Fe₃O₄ compounds with different mass ratios and investigated their microwave absorption properties.Due to the residual defects and oxygen-containing functional groups, r-GO has relatively lower permittivity compared to other carbon materials, which is favor of good impedance match. In the condition of same absorption layer and same reflection layer, the reflection loss of the film reached -5.6 dB when only 0.2 g r-GO was added to the impedance layer. Adding r-GO to the film can improve the film's impedance properties more than adding CB and CNTs. The accuracy of the structure design of three layers film was confirmed by contrasting microwave absorbing properties of the obverse and reverse sides.When changing the added quantity of r-GO from 0.2 g to 1.5 g, the maximum reflection loss gradually migrated to low frequency, and when the added quantity was 0.5 g the best performance in attracting microwave was gotten with the maximum reflection loss reached -5.95 dB, indicating that the added quantity of r-GO in impedance matching layer had a best value. In the condition of adding 0.5 g r-GO to the film, when using new bought CR, the reflection loss reached -8.39 dB at 12 GHz at the thickness of 0.29 mm.To get the r-GO/BaTiO₃ and r-GO/Fe₃O₄ compounds, BaTiO₃ and Fe₃O₄ nanoparticles were dispersed in graphene oxide system respectively and were reduced by hydrazine hydrate. Synergistic effect of different reflection loss mechanism, interface electronic poparization relaxation are all beneficial for the microwave absorbing properties of the compounds. The electromagnetic parameter of the compounds can be tuned by changing the ratio of graphene oxide (GO) and BaTiO₃ and Fe₃O₄. only when the ratio was suitable can the compounds exhibit the best microwave absorption. r-GO/BaTiO₃ showed a maximum reflection loss -12 dB when the ratio of GO and BaTiO₃ was 1:2, and the frequency band that reflection loss was over -8 dB achieved 3.32 dB. The reflection loss intensity of r-GO/Fe₃O₄ didn't change obviously compared to Fe₃O₄'s, but the frequency band was broadened, and the maximum reflection losses of the compounds migrated to low frequency. r-GO/Fe₃O₄ showed a maximum reflection loss -5.7 dB When the ratio of GO and Fe₃O₄ was 1:1, and the frequency band that reflection loss was over -3 dB was from 5.4 GHz to 18 GHz.