Preparation Of Aramid Nanofiber/Mxene/Silicone Rubber Composite And Its Electromagnetic Interference Shielding Application

The modern society promoted the rapid development of the electronics and wireless devices,followed by the presence of electromagnetic radiation problems which also need to be addressed.Therefore,people utilized electromagnetic interference shielding materials to prevent the harm of electromagnetic waves.Due to its flexibility,corrosion resistance,weather resistance and sealing properties required by practical applications,conductive silicone rubber composites stand out among many electromagnetic interference shielding materials.For the conductive composite,its conductivity and electromagnetic interference shielding performance depend on the dispersion and connectivity of the conductive filler in the matrix.However,the traditional blending methods to construct the composite often have the disadvantages of easy aggregation of filler,difficult to disperse,disconnection,large dosage and poor mechanical properties of the composite.Therefore,this paper proposes to construct three-dimensional conductive network aerogel to achieve pre-dispersion of the filler,and then backfill silicone rubber to construct electromagnetic interference shielding composite materials,so as to achieve high electromagnetic interference shielding efficiency with lower filler quantity.In this paper,Ti₃C₂T_xMXene,a new highly conductive two-dimensional nanomaterial,was used as the conductive filler,and Aramid nanofibers（ANFs）was used as aerogels reinforcement material.Porous three-dimensional conductive MXene/ANF aerogels were first constructed as skeletons,and the MXene/ANF/PDMS composites were prepared by backfilling silicone rubber（PDMS）into the aerogels.Due to the weak gelation ability of MXene,ANF with high aspect ratio was introduced to connect MXene lamella to construct aerogel with good mechanical properties and ensure the integrity of conductive pathway in aerogel.At the same time,MXene can disperse ANFs in the dispersion solution,which is conducive to the preparation of uniform conductive aerogel structure by freeze-drying method.The porous aerogel structure is also conducive to the strong dissipation of electromagnetic waves.The above strategy not only builds an efficient conductive network,but also greatly reduces the use of fillers.Therefore,the MXene/ANF/PDMS composite material achieves high conductivity(10.03 S cm^-1)at a lower filler amount（2.89 wt%）,its electromagnetic interference shielding efficiency can reach 40.43 d B,shielding efficiency is up to 99.99%,and has excellent mechanical properties.This kind of lightweight,efficient and flexible electromagnetic interference shielding composite material has very important significance for electromagnetic interference shielding in the field of military industry,aerospace,flexible wearable and other fields.