Preparation Of Nano MnO₂ And Composite And Its Electromagnetic Properties On Fabric

Environmental problems are important topics for human beings.Nanomaterials,compar ed with conventional materials,have unique physical and chemical characteristics such as 1 ight,electricity,magnetism,heat and mechanics.They have unique advantages in solving e nvironmental problems,and have attracted wide attention.In particular,nanocomposites hav e been developing rapidly in recent years,and their advantages in synergy with multiphase materials further expand the application scope of nanomaterials.Nanocrystalline particles of different shapes and sizes have attracted much attention due to their wide applications i n the fields of light,electricity and catalysis.Manganese dioxide has attracted wide attenti on in recent years due to its flexible crystal structure and morphology.Graphene as a two-dimensional structure of carbon nano materials unique,with a huge surface area,high con ductivity and excellent mechanical properties,is often used as a supporting material to im prove the composite optical and mechanical properties,so as to meet the requirements of different fields of application.Fe3O4 has many advantages,such as easy preparation,good chemical stability and low cost.It is widely applied in energy,optoelectronic devices,sen sors and electromagnetic shieldingIn this paper,the influence of nanomaterials and composite nanomaterials on the elect romagnetic properties is analyzed,and the main factors that affect the electromagnetic pro perties of the materials are found out.The rod like MnO2,sea urchin like MnO2,rod Mn O2/RGO,sea urchin like MnO2/RGO and MnO2/RGO/Fe3O4 were prepared by solvothermal method,and the electromagnetic parameters and absorbing properties of the materials wer e tested.Finally,the material was coated on the fabric with the coating agent,and the an ti UV and electromagnetic shielding properties of the fabric were tested.The main researc h results are as follows(1)rod-shaped MnO2 and sea urchin like MnO2 were prepared by solvent heat method,an d the effects of reducing agent,temperature and time on the morphology of MnO2 were s tudied systematically.X-ray diffraction(XRD),scanning electron microscopy(SEM)and Fu Liye infrared spectroscopy(FTIR)were used to characterize and utilize MnO2.The el ectromagnetic parameters are tested and the absorption properties of the rod like MnO2 an d sea urchin like MnO2 are compared.The results show that the absorption performance o f the rod like MnO2 is better than that of the sea urchin like MnO2(2)the preparation of graphite oxide by modified Hummers method,using hydrazine hydrat e as reducing agent on graphene oxide reduction treatment,reduction of graphite oxide(R GO),MnO2/RGO,preparation of rod-shaped urchinlike MnO2/RGO by solvothermal method,and has carried on the use of XRD,SEM,FTIR,at the same time.Test the electromagn etic parameters of rod like MnO2/RGO,sea urchin like MnO2/RGO and absorbing properti es comparing the test results show that the composite with RGO,electromagnetic propertie s of rod-shaped MnO2/RGO and urchin like MnO2/RGO have been significantly improved,and the sea urchin like MnO2/RGO better absorbing property than rod shaped rod MnO2/RGO.The reasons for this phenomenon are analyzed:the excellent microwave absorption properties of sea urchin like MnO2/RGO are mainly due to dielectric loss.The attenuating mechanism based on the antenna mechanism is provided in the composite structure.Whe n the electromagnetic wave is projected onto the structure,the electromagnetic wave energ y is transmitted in the form of a micro current.The prepared sea urchin like MnO2/RGO composite can convert more electromagnetic energy into the form of micro current.The re sulting micro current is transmitted to the spherical structure along the rod like structure,and the spherical structure has the loss mechanism of reflection,scattering and absorption for the electromagnetic wave,and the remaining micro current will be transmitted to the n ext similar structure.In this process,graphene is used as a conductive network,and a par t of the micro current will also be lost during the transmission process.The sea urchin li ke MnO2/RGO improves the impedance matching with the incident electromagnetic wave,and the unique composite structure improves the absorbing properties of the electromagneti c wave.by solvothermal method,Fe3O4 is doped into the sea urchin like MnO2/RGO,pre pared by RGO/MnO2/Fe3O4,by using X ray diffraction(XRD),infrared spectroscopy(Fu Liye FTIR)of the composites were investigated,by changing the content of Fe3O4,compa red to the final composite absorbing properties.It is found that the overall reflectivity of t he Fe3O4 composite is improved,the wave absorption performance is enhanced and the m aximum reflectivity is enhanced.With the increase of the ratio of Fe3O4,the reflectivity o f RGO/MnO2/Fe3O4 increases and the maximum reflectivity moves slightly to the right.Th e cause analysis may be the incorporation of Fe3O4,which is conducive to the formation of a new conductive network.The transfer of electrons between the interfaces hinders the reduction,thereby weakening the electromagnetic energy,thereby enhancing the overall mic rowave absorbing properties of the composite(3)The preparation of RGO,RGO/MnO2,RGO/MnO2/Fe3O4 coated on the surface of the f abric as coating agent,coating agent and the change in coating agent for fabric covering t hickness under the condition of coated fabrics were surface resistance test,fabric weight g ain rate test,fabric thermal stability test,anti ultraviolet performance testing,performance t esting of fabric electromagnetic shielding effectiveness.The results show that RGO/MnO2/F e3O4 has good electromagnetic shielding effect.Meanwhile,the thickness of coating and th e content of composite material in coating agent are also the key factors affecting the ele ctromagnetic shielding effectiveness of fabrics.