Preparation And Electromagnetic Properties Of 2D Mxene Based Nanocomposite Materials

Due to the update of weapons and the constant innovation of arms technology,higher and higher demands are put forward for the technology of absorbing waves.The single component absorbent can not be satisfied with the practical application,so the nanocomposite has become a hot spot in the field of absorbing waves.The multi-layer MXene nanosheets with different loss mechanisms were compounded with NiFe2O4,and then the ternary compounding with PPy could not only reduce the weight of the traditional ferrite absorbent,but also effectively avoid the agglomeration of nanoparticles.Meanwhile,the different loss mechanisms could also achieve better wave absorption performance.In this paper,MXene/NiFe2O4 binary composite material and MXene/NiFe2O4/PPy ternary composite material were prepared and synthesized based on MXene nanometer sheet.The main work is as follows:1.The direct HF etching method was used to explore the influence of HF volume and concentration on the etching effect of Ti3AlC2 powder.The results showed that by adding 20ml HF solution with a concentration of 30%and etching at 35? for 24h,multilayer MXene nanometer sheets with the largest layer spacing and complete lamellar structure could be obtained.The effect of layer extender,temperature and time on the effect of layer extender was studied,and the optimal process of layer expansion was obtained as follows:DMF was used as the layer extender and heat treated at 120?for 8h,which could effectively increase the layer spacing without damaging the multi-layer structure and increase the layer spacing of the nanometer sheet to 1.33nm2.MXene/NiFe2O4 nanocomposites with different composite proportions were prepared by simple hydrothermal method and heat treatment at the optimal process conditions of 180° for 12h.NiFe2O4 grains were observed to crystallize between layers of MXene.The electromagnetic properties of composites were studied.The complex dielectric constant increased with the addition of MXene nanometer sheets,while the complex permeability decreased with the increase of MXene nanometer sheets.The wave absorbing properties of MXene/NiFe2O4 composite were studied.With the increase of MXene nanocrystalline content,the wave absorption performance of the composite was enhanced.When the thickness of 40%MXene/NiFe2O4 was 2.5-3.0mm,the minimum reflection loss of-41.2db was obtained at 13.2 GHz.In addition,with the increase of MXene nanosheet content,the absorption peak moved from 16.8GHz to 13.2GHz.3.MXene/NiFe2O4/PPy ternary composite material was prepared by in situ compounding method.The electromagnetic properties of the composite material were studied.The absorbing properties of the ternary composites were studied,and the results showed that the minimum reflection loss of-45.4 dB was obtained at 15.5GHz with the thickness of 1.5mm.Compared with the binary composite material,it can obtain better wave absorbing performance at a thinner thickness...