Experiment Of Flexible CNT/SA/PDMS Electromagnetic Shielding Composite

Electromagnetic shielding materials can absorb or reflect electromagnetic waves to reduce or eliminate electromagnetic waves to human body,electronic devices and the environment caused by damage and pollution.Carbon nanotubes are widely used in flexible electromagnetic shielding due to their low density,high flexibility and high electrical conductivity.To solve the problem of inadequate magnetic shielding performance of carbon nanotubes/sodium alginate/polydimethylsiloxane(CNT/SA/PDMS)composites,two new CNT/SA/PDMS composites were designed and prepared from the perspective of permeability and conductivity optimization.Respectively,carbon nanotubes/sodium alginate/carbon nanotubes/polydimethylsiloxane(CNT/SA/CNF/PDMS),nickel coated carbon nanotubes/sodium alginate/polydimethylsiloxane(Ni@CNT/SA/PDMS).By studying the microstructure,mechanical and electrical properties,electromagnetic shielding(EMI-SE)properties and shielding mechanism of materials,the main conclusions are as follows:(1)The elongation at break of CNT/SA/PDMS,Ni@CNT/SA/PDMS and CNT/SA/CNF/PDMS flexible composites can reach 25%,32% and 35%,respectively,within the elastic deformation range(9%),and their electrical conductivity does not change with the strain.(2)The electrical conductivity of CNT/SA/PDMS composites increases with the increase of CNT content.With the increase of CNT content from 0 wt.% to 1wt.%,the electrical conductivity of CNT/SA/PDMS composites increases from10-7.1 S/m to 10-3.4S/m.The electrical conductivity of Ni@CNT/SA/PDMS composites increased from 10-7.1s /m to 10-2.7s /m,which was slightly improved compared with the former.However,the electrical conductivity of CNT/SA/CNF/PDMS composites increased from 10-6.1S/m to 10-1.7S/m,which was attributed to the uniform dispersion of CNT in the matrix promoted by the addition of CNF.(3)EmI-Se values of composite materials increase with the increase of CNT.When CNT content is 1%,The maximum em I-Se values of CNT/SA/PDMS,Ni@CNT/SA/PDMS and CNT/SA/CNF/PDMS composites are 3.5d B,6.5d B and6.8d B,respectively.The electromagnetic shielding mechanism of Ni@CNT/SA/PDMS is mainly absorption.The electromagnetic shielding mechanism of CNT/SA/PDMS and CNT/SA/CNF/PDMS composites is mainly reflection.47 Figures,6 Tables,91 References are contained...