Study On Preparation Of Carbon Nanofibers By Air Spinning And Electromagnetic Shielding Properties

Since mankind entered the information age,the development of science and technology has brought earth-shaking changes to mankind.Especially since the 21st century,with the construction of global communication system,artificial electromagnetic radiation has also increased.Electromagnetic radiation has gradually developed into a new type of pollution caused by the universal use of electronic communication,affecting people’s normal life.With the increasing demand for electromagnetic shielding,the application environment of electromagnetic shielding materials has become complicated.Flexible materials with excellent electromagnetic shielding properties are urgently needed.Carbon nanofibers have become an excellent research direction in this field because of their excellent electrical conductivity,flexibility and mechanical properties.As a new method for large-scale preparation of multi-system nanofibers,jet spinning technology has gradually attracted the attention of relevant researchers.Because of the uniqueness of the materials prepared by this technology,this new fiber making method can meet the demanding demands of many aspects and has great practical value in many application fields.In this study,carbon nanofibers prepared by air spinning technology were studied,and the large-scale preparation of polyacrylonitrile fibers based on air spinning technology was realized.On this basis,through the study of fiber preoxidation and carbonization process,the electromagnetic shielding material of polyacrylonitril-based carbon nanofibers with good electromagnetic shielding effect and excellent mechanical strength was successfully prepared.The electromagnetic shielding efficiency of carbon nanofibers at different annealing temperatures was studied.Finally,attempts are made to improve the electromagnetic shielding properties of carbon nanofibers.The details are as follows.First,the principle of air spinning and the constitution of air spinning equipment were understood,and the whole process of preparing polyacrylonitrile nanofibers by air spinning technology and converting nanofibers into carbon nanofibers was realized.In the annealing process,carbon nanofibers with different electromagnetic shielding effects were prepared by changing the annealing temperature.The electromagnetic shielding effects of carbon nanofibers and the morphological characterization of carbon nanofibers were discussed.Then,the improvement of electromagnetic shielding efficiency of carbon nanofibers is discussed,and two methods are proposed.One of them is to coat the surface of carbon nanofibers with conductive coating,which combines the two to form a new electromagnetic shielding material.The method of coating conductive material can effectively enhance the electromagnetic shielding efficiency of carbon nanofibers and reduce the annealing temperature requirement of carbon nanofibers.The second method is to use PVB solution to attach conductive or magnetic materials to the surface of carbon nanofibers,so as to try to improve the electromagnetic shielding performance of carbon nanofibers.Finally,it is confirmed that silver nanowires attached have a good improvement on the electromagnetic shielding performance of carbon nanofibers.Finally,the stability of carbon nanofibers attached with silver nanowires was tested,and the attenuation of the electromagnetic shielding performance of the material was tested at high temperature,which confirmed the applicability of the carbon nanofibers attached with silver nanowires in real life.