Preparation And Study Of Composites Based On Polypyrrole And Their Microwave Absorption Properties

With the rapid development of modern science and technology and the increasing of the popularization of electronic equipment,the electromagnetic wave is not only related to the military field but also related to our daily life.Long-term excessive electromagnetic radiation will cause a lot of inconvenience to people's life,the electromagnetic radiation will affect human health,damage human immune system and threaten human healthPolypyrrole?PPy?has the characteristics of light weight and high conductivity,and it is easy to prepare,therefore,it is one of the most widely studied conductive polymers.The oxidized and doped polypyrrole is a kind of conductive polymer material,which will convert electromagnetic energy into thermal energy and other energy to consume electromagnetic waves by using the interaction of the electric fieldAl₂O₃@PPy@rGO composites with core-shell structure were prepared by a three-step method.The structure,morphology and properties of Al₂O₃@PPy@rGO ternary composites were characterized by FTIR,XRD,SEM,TEM,Raman and TGA,etc.The complex dielectric constant of the Al₂O₃@PPy@rGO composites was measured by the vector network method,and the wave absorbing properties were analyzed and calculated.The experimental results showed that when the thickness is 3.0 mm,the content of Al₂O₃@PPy@rGO composites in the Al₂O₃@PPy@rGO-wax-based composites is about 15%,the maximum reflection loss of Al₂O₃@PPy@rGO composites is-39.7dB.And the effective microwave absorption bandwidth can reach 5.5 GHz in the frequency range of 10.5-16.0 GHz.At the same time,the mechanism of microwave absorption of Al₂O₃@PPy@rGO composites was analyzedNi@SiO₂ nanospheres were synthesized by the Stober method,and Ni@SiO₂@PPy composites were prepared by in-situ polymerization.The structure and morphology of Ni@SiO₂@PPy composites were characterized by FTIR,XRD,SEM,TEM,etc.The complex permittivity and complex permeability were measured by the vector network method,the dielectric loss and magnetic loss were calculated,and the wave absorption capacity was further analyzed and calculated.The experimental results showed that when the content of Ni@SiO₂@PPy composites in Ni@SiO₂@PPy-wax composites is 15%and the thickness is 2.5 mm,the effective absorption bandwidth of Ni@SiO₂@PPy composites is about 4.3 GHz in the range of 10.6-14.9 GHz,and the maximum reflection loss at 12.6 GHz is-23.9 dB.This can be attributed to the synergy between complex permittivity and complex permeability.The mechanism of microwave absorption of Ni@SiO₂@PPy composites was analyzed.And it will provide guidance to the research in this fieldAl₂O₃@PPy@rGO composites and Ni@SiO₂@PPy composites based on PPy have good microwave absorption properties,and they will have broad development prospect in the future.