| In order to better cope with the increasingly serious electromagnetic pollution problem,Based on the concept of preparing shielding fiber by magnetic powder blending modification was proposed.With the help of blending modification process,orthogonal experimental design method and flange coaxial electromagnetic shielding test,nano-Fe3O4 was compounded with nylon 66 by blending spinning method.The nano-Fe3O4 modified nylon 66 fiber was prepared.At the same time,environmentally friendly chemical copper plating and electroless nickel plating processes that could improve the shielding effectiveness of the nylon 66 fabric were studied,and the process was applied to the chemical plating of the nano-Fe3O4 modified nylon 66 fiber surface.The specific research contents are as follows:(1)The hydrothermal method was used to synthesize?-Fe2O3,Fe3O4 and Ni-Fe3O4nano-ferrite particles.The magnetic performance analysis showed that Fe3O4 has the highest saturation magnetization among three materials,which can reach 85.027 emu/g.The three materials were mixed with water-based polyurethane in the same proportions to prepare electromagnetic shielding coatings and coated on nylon 66 fabric.The electromagnetic shielding test of waterborne polyurethane containing Fe3O4 coatings on nylon66 fabric showed that the electromagnetic shielding effectiveness can reach 6 d B in the frequency range of 100 k Hz to 1 MHz.The electromagnetic shielding effectiveness of Ni-Fe3O4 coating is up to 5d B,and the?-Fe2O3 coating has no electromagnetic shielding effectiveness.Selecting nano Fe3O4 as the modified nylon 66material.(2)Nano-Fe3O4 was blended with nylon 66 slices at a mass ratio of 1%,2%,3%,4%,and 5%through blending and modified spinning to prepare nylon66 staple fibers with different nano-Fe3O4 content.As the amount of Fe3O4 adde d increases,the mechanical properties of short fibers decrease and the magnetic properties increase.As the amount of nano-Fe3O4 added increases,the spinneret will become clogged and the filter will break down during the spinning process.Choose 0.8mm aperture spinneret and 160 mesh filter,and use 2%nano Fe3O4/nylon 66 slices for melt spinning.The nascent filament obtained can have a brea king strength of 0.5 c N/dtex,and then nano Fe3O4/nylon 66 The filament is wov en into a fabric sample and the electromagnetic shielding effectiveness of the mo dified fabric sample in the range of 100 k Hz?1 MHz is up to 1 d B;(3)Using nylon 66 fabric as the object,through the design of orthogonal ex periment method,and using electroless plating speed as the judging standard,the main influencing factors of Na H2PO2 electroless copper plating are Na OH>Na H2PO2·H2O>Ni SO4>Na3C6H5O7·2H2O>temperature.Combined with the test method o f the firmness of the fabric coating,the effect of the concentration of Na OH an d Na H2PO2 on the electroless copper-plated fabric was explored.The research sh ows that when the concentration of Na OH and Na H2PO2 are 25 g/L and 70 g/L,the coating effect is the best,Study has obtained the best chemical copper plati ng formula.After the nylon 66 fabric is electroless plated with this formula,the electromagnetic shielding effectiveness of the fabric in the range of 30 MHz to1.5 GHz is 65 d B,and the corrosion current density is 2.307×10-5A/cm2.Whe n further electroless nickel plating on the fabric,the electromagnetic shielding eff ectiveness(70 d B)and corrosion resistance(corrosion current density of 1.042×10-5 A/cm2)of the fabric can be improved.(4)When the electroless copper plating and electroless nickel plating proces ses are applied to the surface of nano-Fe3O4/nylon 66 fiber,XRD analysis shows that the fiber exhibits characteristic diffraction peaks of copper,nickel,Fe3O4 af ter electroless plating,and can be observed in metallographic microscope Obviou s metal nickel and metal copper plating. |
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