Study Of Electromagnetic Shielding Performance Of Ti₃C₂T_x/PPy Composites

With the maturity of the fifth generation(5G)mobile communication technology,various electronic devices have brought great convenience to people while inevitably generating some electromagnetic pollution.These electromagnetic pollution can interfere with the normal operation of electronic components,and can even endanger human health.For the above problems,the development of high-performance electromagnetic interference(EMI)shielding materials is one of the effective ways to solve electromagnetic pollution.Intrinsically conductive polymers with low density,corrosion resistance,high strength and other advantages have attracted attention.Among them,Polypyrrole(PPy)has the general characteristics of conductive polymers,but also has the characteristics of environmental friendliness,easy to synthesize on a large scale,and low cost.However,the relatively low electrical conductivity of intrinsically conducting polymers leads to unsatisfactory electromagnetic interference shielding effects.The preparation of conductive filled composites is now a common method to enhance the electrical conductivity of conductive polymers.Ti₃C₂T_xMXene,as an emerging two-dimensional material with good electrical conductivity,unique layer structure,and abundant surface groups,is an ideal conductive filler material.In this thesis,Ti₃C₂T_x/PPy composites were successfully designed and prepared by a simple in situ polymerization and mixing method,and the electromagnetic shielding properties of the materials were investigated,with the following main research work.The few layers Ti₃C₂T_xnanosheets and V₂CT_xwere synthesized by etching Ti₃Al C₂and V₂Al C powders through HCl-Li F mixed with in situ generated HF,and Ti₃C₂T_x-Ag composites were conveniently synthesized using the redox reaction between Ti₃C₂T_xand Ag NO₃.The successful preparation of Ti₃C₂T_x,V₂CT_xand Ti₃C₂T_x-Ag was confirmed by characterization of Ti₃C₂T_x,V₂CT_xand Ti₃C₂T_x-Ag by SEM,XRD,XPS and EDS.The conductivity of Ti₃C₂T_x,V₂CT_xand Ti₃C₂T_x-Ag films synthesized by different masses of Ag NO₃was measured by the four-probe method.The results show that in Ti₃C₂T_xis a very good conductive material and can be used as a conductive filler.Based on the previous work,Ti₃C₂T_x/PPy composites were successfully prepared for electromagnetic interference shielding applications by a simple in situ polymerization method and mixing process.We investigated the electrical conductivity,thermal stability,electromagnetic interference shielding effect and its electromagnetic shielding attenuation mechanism of Ti₃C₂T_x/PPy composites.By adjusting the content of Ti₃C₂T_xin Ti₃C₂T_x/PPy composites from 0 to 12 vol%,the conductivity of the composites increased significantly from 34.6 to 884.1 S m-1,and the maximum electromagnetic shielding effect of the composites in K_u-band increased from 4.30 to21.82 d B accordingly.In addition,due to the addition of Ti₃C₂T_x,Ti₃C₂T_x/PPy(12 vol%)composite has improved thermal stability,with mass loss changing from 59.25%to29.34%at 900°C.These results highlight that the investigated Ti₃C₂T_x/PPy composites are promising electromagnetic shielding shielding materials.This study provides an experimental basis for improving the electromagnetic shielding performance of conductive polymer materials.