Preparation And Properties Of Electromagnetic Shielding Poly-P-Phenylene Terephthamide Non-Woven

Since the 21st century,with the rapid development of science and technology,electromagnetic wave has been everywhere.This poses new challenges for information protection and biosecurity.At present,electromagnetic shielding materials based on conductive metals mainly achieve the purpose of shielding electromagnetic wave by reflecting electromagnetic wave,which is easy to cause secondary pollution of electromagnetic wave.Therefore,materials with excellent electromagnetic shielding performance and electromagnetic wave absorption ability have become a research hotspot at present.Non-woven fabric has the advantages of good flexibility,light weight and large specific surface area.Its porous structure can effectively reflect and absorb electromagnetic waves at multiple interfaces,which is a good substrate for preparing electromagnetic shielding materials.In this paper,polydopamine（PDA）was used to modify para arylon non-woven fabric（PPTA）,and then silver plating was performed on PPTA/PDA to prepare silver plated arylon non-woven fabric（PPTA/PDA/Ag）.The optimal modification conditions were obtained by orthogonal test:the concentration of dopamine（DA）solution was 0.81 g/L and the modification time was 24 h.The optimal silver plating conditions are as follows:silver nitrate（Ag NO₃）solution concentration 12 g/L,ammonia（NH₃·H₂O）concentration 8 m L/L,glucose concentration 20 g/L.The surface resistance of PPTA/PDA/Ag non-woven fabric based on the optimum modification and silver plating conditions can reach 16.3 mΩ/sq,and the electromagnetic shielding efficiency can reach103.92 d B in the X band（8.2-12.4 GHz）,mainly reflecting electromagnetic wave.In order to enhance the absorption ability of electromagnetic wave,Fe₃O₄ was sprayed on the surface of PPTA/PDA/Ag non-woven fabric,and Fe₃O₄-coated arylon non-woven fabric（PPTA/PDA/Ag/Fe₃O₄）was prepared.The arylon non-woven shielding material with inner layer of Ag and outer layer of Fe₃O₄ was formed.The effect of spraying time on electromagnetic shielding performance of PPTA/PDA/Ag/Fe₃O₄ non-woven fabric was discussed.The results show that with the increase of spraying time,the total electromagnetic shielding efficiency of PPTA/PDA/Ag/Fe₃O₄ non-woven fabric decreases gradually,and the absorption coefficient of electromagnetic wave increases gradually.After spraying for 240 s,the total electromagnetic shielding efficiency is 55.92 d B and the average absorption coefficient is 0.184.In order to improve the absorption ability of electromagnetic wave without reducing the overall efficiency of electromagnetic shielding,Fe₃O₄ doped with MXene was doped and sprayed on the surface of PPTA/PDA/Ag to prepare the silver coated arylon non-woven fabric sprayed Fe₃O₄@MXene（PPTA/PDA/Ag/Fe₃O₄@MXene）.The results show that the total electromagnetic shielding efficiency of PPTA/PDA/Ag/Fe₃O₄@MXene composite non-woven fabric is higher than 89 d B,and the average absorption coefficient is increased to 0.203 after 240 s spraying.