| In the current Internet of Thinngs era,with the rapid development of electronic communication equipment,problems such as electromagnetic radiation,electromagnetic interference(EMI)and information leakage caused by electromagnetic waves have become increasingy serious.The development of lightweigh,high-performance,and absorption-based Electromagnetic shielding protective packaging materials,to reduce the impact of electromagnetic interference and radiation on the contents,and to protect the human body and information security,has important market value and strategic significance.In recent years,a new type of two-dimensional material MXene(Ti3C2Tx)had shown great application potential in the field of high-efficiency electromagnetic interference shielding by virtue of its ultra-high metal conductivity,large specific surface area,low density,djustable active surface and many other advantages.In this paper,a sandwich structure composite film and porous foam were constructed based on the large-size Ti3C2Tx and the precipitate after stripping the large-size single-layer Ti3C2Tx,respectively,and explored their electromagnetic shielding effectiveness(SE).The main research contents are as follows:(1)Using the HCl-LiF in-situ generation HF etching method the etching effects of 6 mol/L HCl and 9 mol/L HCl on Ti3AlC2 were investigated respectively.Research shown that the monolayer Ti3C2Tx prepared by 9 mol/L HCl etching had high content and good effect.In addition,the core-shell Fe3O4@PANI particles were prepared by co-precipitation method and in-situ growth method.The results indicated that when the surface of Fe3O4 was coated with a layer of PANI,the shape of Fe3O4 in PANI became irregular,and the size was further reduced,but the agglomeration phenomenon was significantly reduced.(2)The sandwich structure Ti3C2Tx composite film was prepared by the vacuum-assisted filtration method.SEM,XRD,XPS,etc.test results exhibited that Fe3O4?PANI existed uniformly in Ti3C2Txfilm without destroying the structure of Ti3C2Tx,and the electrical conductivity decreased with the increase of Fe3O4@PANI.At the same time,the EMI performance test of the composite film with different Ti3C2Tx content was carried out.The results indicated that when the mass ratio of Fe3O4@PANI and Ti3C2Tx nanosheets was 12:5,the maximum EMI SE was 58.8 dB with the thickness of 12.1 ?m.This SE was much higher than the pure Ti3C2Tx film of the same thickness.In addition,by increasing the Ti3C2Tx concentration to adjust the film thickness,when the thickness was 16.7 ?m,the SE can be as high as 62 dB.(3)The precipitation after separating the single layer of MXene was compounded with polyvinyl alcohol(PVA),and MXene/PVA foam was prepared by vacuum freeze-drying technology.The results shown that the composites prepared with many small-sized and multi-layer Ti3C2Tx and unetched Ti3AIC2 precipitates as conductive fillers exhibited an EMI SE of up to 46.7 dB.The preparation method greatly improves the utilization rate of Ti3C2Tx,thereby further broadening the potential application value of the Ti3C2Tx. |
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