Studies On The Preparation And Properties Of Mos₂-based Composites Absorbing Material

At present,electromagnetic wave absorbing materials are developing in the direction of“thin,light,wide and strong”,and composite multi-band absorbing materials have become the development trend and research hot spot in the future.In this paper,firstly,molybdenum disulfide was prepared by one-step hydrothermal method using molybdenum trioxide and potassium thiocyanate as the molybdenum source and sulfur source for the reaction.The effect of hydrothermal temperature on molybdenum disulfide crystal form was studied.The optimum reaction temperature was determined by XRD analysis.The electromagnetic parameters of materials in the range of 1-18 GHz were tested using a vector network analyzer,and the absorption performance of this frequency band was simulated.It was found that the minimum reflection loss of molybdenum disulfide reached-16.93 dB when the matching thickness was 5.0 mm.The attenuation performance of materials was tested by the millimeter wave attenuation test system.When the loading amount was 0.6 g,the 3 mm and 8 mm wave attenuation performance of molybdenum disulfide were the best,and their corresponding maximum attenuation values were 6.45 dB and 6.63 dB,respectively.Secondly,molybdenum disulfide/reduced graphene oxide composites were prepared by one-step hydrothermal method.The composition and microstructure of the composites were determined by XRD,Raman,FESEM and TEM analysis.The electromagnetic parameters of the composites were tested using a vector network analyzer,and the absorption performance in the centimeter band was simulated.It was found that the sample G-2 had the best reflection loss performance,the minimum reflection loss was-48.54 dB,and the maximum effective absorption bandwidth was 4.16 GHz.When the coating thickness was constant,with the increase of graphene oxide,the reflection loss showed the trend of rising first and then falling.The millimeter wave attenuation performance of the composites was tested by the millimeter wave attenuation test system.It was found that the millimeter wave attenuation capability of molybdenum disulfide/reduced graphene oxide composites showed a rising trend with the increase of graphene oxide,and the maximum 3 mm and 8 mm attenuation values reached21.75 dB and 21.83 dB,respectively.Then,we have adjusted the preparation process of molybdenum disulfide,and selected the ionic sodium molybdate dihydrate and thioacetamide as the molybdenum source and sulfur source for the reaction.The prepared molybdenum disulfide powder was modified by the silane coupling agent KH-550,and molybdenum disulfide/polyaniline composites were prepared by in-situ chemical oxidation polymerization.The morphology and composition of the composites were determined by FESEM,TEM,XRD,FTIR and BET specific surface area analysis.The electromagnetic parameters of materials were tested by a vector network analyzer,and the absorption performance in the centimeter band was simulated.It was found that the sample MoS₂-PANI-0.5 had the best reflection loss performance.When the matching thickness was 2.0 mm,the minimum reflection loss reached-40.79 dB,and the maximum effective absorption bandwidth was 5.02 GHz.When the coating thickness was constant,with the increase of polyaniline,the reflection loss showed the trend of rising first and then falling.The attenuation performance of materials was tested by the 3 mm wave attenuation test system.It was found that with the increase of polyaniline,the 3 mm wave attenuation capability of composites gradually increased,and the maximum attenuation value reached15.45 dB.Finally,molybdenum disulfide/polypyrrole composites were prepared by in-situ chemical oxidation polymerization.The microstructure and composition of the composites were determined by FESEM,TEM,XRD and FTIR analysis.The conductivity of the composites was measured by the four-probe tester,and the attenuation performance of the composites was tested by the 3 mm wave attenuation test system.It was found that the conductivity and 3 mm wave attenuation performance of the composites were increased with the increase of polypyrrole,and the maximum attenuation value reached 12.36 dB.When the type of dopant in the polymerization reaction was changed,the conductivity of the composite doped with p-toluenesulfonic acid was the highest,and 3 mm wave attenuation was the best.