Synthesis And Properties Of Zeolite Based Microwave Absorption Nanocomposites

The rapid development of microwave and electronic technology has brought convenience to people's life,meanwhile,new electromagnetic pollution and interference to the environment is also increasing.Therefore,microwave absorbing materials have become one of the hot spots in the research and development field of electromagnetic materials.For the moment,the drawbacks of existing microwave absorbing materials greatly limit their large-scale application in the practical production.Consequently,the study of new absorbing materials with"thin thickness,wide frequency band,light weight and strong absorption"has become the development trend in this field.In this thesis,the complex wave absorbing materials composed mainly by zeolite?NaA?and graphene,manganese bioxide and zinc oxide are designed and prepared by using the unique electromagnetic properties of graphene,the semiconductor dielectric loss characteristics of manganese bioxide and zinc oxide and special porous framework of zeolite.And we verify the materials the materials have excellent electromagnetic wave absorption capacity in the frequency range of 2-18 GHz.On this basis,the relationship between the microwave absorbing properties of the composites and the distribution and morphology of the composites is systematically studied,The main results are summarized as follows:?1?We investigated the absorbing properties of target composite materials,which were the combination of graphene with different states and zeolite by freeze drying treatment procedures.Among the resulting materials,Thermal expansion graphene?RGO?and zeolite resulting composite material is found with excellent absorbing properties,and considered as a dielectric loss absorbing material.?2?The NaA/MnO₂ and Fe doped ternary absorbing materials were designed and fabricated.And the results of absorbing properties showed that the two composites were electrified absorbing materials.The Fe/NaA/MnO₂ had better absorbing properties,which had strong absorbing properties at low frequency,as well as an effective absorption bandwidth of 4.0 GHz at high frequency.?3?The effect of Fe/NaA content on the microwave absorbing properties of the composites materials was investigated.And then the composites with different molar ratios were prepared and compared.The results showed that the microstructure of composites was the micro nano structure composed of sea urchin-like microspheres and flower shaped nanoparticles when the molar ratio of Fe/NaA:KMnO4 was 1:8.3and its absorption property was the best.The reflection loss of the composite was-59.9 dB and the effective absorption frequency range was 3.21-18 GHz when the thickness changed from 2.0-5.5 mm,and the absorption peaks value of each thickness were less than-39 dB.?4?A new type of ZnO/NaA/PB ultra thin sheet structure was designed and prepared by using the porous structure of zeolite and prussian blue?PB?via hydrothermal synthesis method.The growth mechanism of ZnO/NaA was revealed through the study of the formation of the nanosheets,which elucidated the important effect of solvent concentration on the growth and microstructure of ternary composite materials.It is found that the maximum reflection loss of ZnO/NaA/PB composite was-27 dB and the matching thickness was 2.5 mm.The above study shows that this all-inorganic absorbing materials have the characteristics of light weight,wide frequency band and strong absorption.Thus,the materials are considered to have broad application prospects in the future military and civil fields.