Prepaeation And Emi Appligation Of Rgo Aerogel And RGO/GNS/PVA Composite Foams

Electromagnetic shielding materials are produced with the application of electromagnetic waves and are widely used in various fields such as military stealth,advanced electronic equipment electromagnetic shielding and civil communication protection.In recent years,with the further development of the Internet era,people have become unprecedentedly dependent on electronic devices,resulting in the widespread use of electronic devices.As a result,a large number of electromagnetic waves are generated in the environment on which people live,affecting People's Daily life and even endangering people's health.Today,the further development and application of a new generation of electromagnetic detection technology(terahertz)has posed a new challenge to the study of electromagnetic shielding.Electromagnetic shielding materials have been developing in the direction of high efficiency,wide frequency,light weight and high strength.However,traditional single metal-based and polymer-based electromagnetic shielding materials can not meet the demand.Therefore,the development of light electromagnetic shielding materials with high electromagnetic anti-interference shielding performance and low density is a hotspot in the field of electromagnetic shielding research,which is of great significance for improving the application effect of electromagnetic shielding materials.Graphene,with its ultra-high specific surface area and electrical conductivity,shows great potential in electromagnetic shielding applications.Graphene foam can not only give full play to the unique physical and chemical properties of graphene,but also further reduce the density of the electromagnetic shielding body and improve the electromagnetic shielding performance of the electromagnetic shielding,thus providing a new development space for the new generation of electromagnetic shielding materials.In this paper,a large multi-sheet of go was prepared by improved Hummer method,and a self-assembly method was used to synthesize a mesoporous rGO aerogel with strong elasticity and large specific surface area using self-made go as raw material.rGO/GNS/PVA composite foams were prepared by sol-gel method,and commercial rGO/GNS/PVA composite foams were obtained by adjusting the content of rGO/graphene nanosheet/PVA composite foams.Specific research contents are as follows:1.GO sheets were prepared by modified Hummer method and oxidized to obtain GO sheets.Morphology of GO sheets was characterized by SEM,TEM,AFM and other characterization methods.Structure and functional groups of GO sheets were characterized by XRD,FTIR and Raman.2.Using self-made GO as raw material,rGO aerogel was prepared by solvent replacement,hydrothermal synthesis,freeze drying and annealing.SEM characterization was used to demonstrate the continuous interconnect network structure of rGO aerogel.BET test was used to characterize the surface area and pore diameter of rGO aerogel,and XRD,FTIR and Raman tests were used to characterize the reduction of GO.Finally,rGO aerogel was obtained.In addition,this study further studied the influence of annealing temperature on the structure of rGO aerogel,and found that the reduction degree of GO could be improved with the increase of annealing temperature.3.GO/GNS/PVA composite foam materials were synthesized by sol-gel method.The composite foam after heat treatment not only reduced the GO components to obtain the rGO sheet layer,but also suffered from complex reaction processes such as dehydroxylation reaction and decarboxylation reaction in the heat treatment process,which increased the conductivity and heat transfer performance of the materials.SEM characterization method was used to characterize the microstructure of rGO/GNS/PVA composite aerogel.It was found that the prepared composite foam has an interconnected three-dimensional network structure,which increases phonon scattering and carrer migration,and further improves the thermal and electrical conductivity of the composite foam.By controlling the content of rGO/CNS,we explored the influence of the content on the thermal conductivity,electrical conductivity and electromagnetic shielding performance of the composite foam.It was found that with the increase of rGO/GNS,the heat transfer,electrical conductivity and electromagnetic shielding efficiency of the material were increased to different degrees.In particular,when the content of rGO/GNS increased to 24 wt%,the electromagnetic shielding efficiency of 4mm thick composite foam reached 46.8 dB,which was far beyond the requirements of commercial standards.