| The increasing human demand for intelligent and electronic equipment and product applications directly leads to a sharp increase in space multi-spectrum electromagnetic radiation,which endangers human health and seriously affects the operational safety of military and civilian instruments,meters,and electronic equipment.High-performance electromagnetic shielding materials are an important technical way to reduce or eliminate electromagnetic pollution,among which,electromagnetic shielding fabric has become one of the hot spots of electromagnetic shielding materials research because of its light and flexible,wearable,and environmentally adaptable characteristics.Two-dimensional transition metal carbon/nitride(MXene)has significant advantages for application in electromagnetic shielding fabrics due to its excellent electrical conductivity and abundant surface polar groups.However,the weak interfacial interaction between MXene nanosheets and fabric substrates can lead to poor stability and mechanical fastness of shielding fabrics in the macroscopic structure,and stable working life becomes a bottleneck for applications.Because of this,the main research contents of this thesis work are as follows:(1)The preparation of MXene and characterization of its electromagnetic shielding fabric.The microscopic morphology and structural composition of MXene were tuned by different etching methods,and the minimum intensity layering method was used to prepare MXene materials after comparison.The microstructure analysis showed that the layer less MXene nanosheets obtained by this preparation method have morphological features of larger size and smaller defects.The high quality flexible electromagnetic shielding fabric was further prepared by assembling MXene as fabric coating,and the correlation between its stability and shielding effectiveness and the preparation process was investigated.It was concluded that MXene shielding fabric had good electrical conductivity and electromagnetic shielding performance,and its shielding efficiency at X-band reached 31.36 d B while remaining light,flexible,and foldable.(2)The preparation of MXene-Sodium Alginate(MXene-SA)high-performance shielding fabric and its performance study.The MXene-SA material with a stable interlayer structure was synthesized and combined with the fabric substrate by a one-step assembly method to prepare a high-performance MXene-SA electromagnetic shielding fabric.The MXene-SA fabric maintained good electromagnetic shielding performance(30.95 d B,X-band)while improving its stability under mechanical damage,chemical corrosion,and ultrasonic decomposition.The synergistic effect of the oxygen-containing groups of SA and the Ti atoms at the end of MXene in the composite coating enhanced the chemical stability of the fabric and improved the oxidation resistance of the fabric.In addition,the one-step assembly technique is simple to operate and easy to fabricate,showing potential applications in the field of electromagnetic shielding.(3)The preparation of MXene-SA composite fabrics cross-linked with calcium ions and the study of its properties.The calcium ions were used to post-treat the MXene-SA fabric,and the calcium ion cross-linked MXene-SA(CMS)composite fabric was prepared by a stepwise assembly method.The addition of calcium ions further enhanced the overall mechanical fastness and resistance to the ultrasonic decomposition of the fabric and maintained good electrical stability under different humidity environments.Compared with MXene-SA fabric,its shielding effectiveness was enhanced by 17.44%(36.35 d B,X-band).At the same time,the CMS fabric demonstrated long-term stability under bending and peeling and acidic and alkaline environments. |
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