Interface Design And Properties Of Carbon Fiber Reinforced Polyphenylene Sulfide Electromagnetic Shielding Composites

With the rapid development of intelligent,digital devices and communication technology,electromagnetic radiation has become an increasingly serious problem in people’s lives.In order to protect precision instruments and human health,it has become more and more important to develop electromagnetic shielding materials with excellent shielding performance.In recent years,conductive polymer composites have developed rapidly in the field of electromagnetic protection due to their low density,good processability and formability,and designability.However,the current electromagnetic shielding composites usually have only a single shielding performance,and their mechanical properties are poor due to poor interfacial bonding.Therefore,the dual regulation of electromagnetic shielding performance and mechanical properties of electromagnetic shielding composites,as well as the multi-functionalization of materials are the key directions of current research.This paper aims at greening and simplifying the metallization process of conductive polymer composites,interfacial structure design and performance study,a new multifunctional electromagnetic shielding composite material with dual regulation of electromagnetic shielding and mechanical properties was prepared.The relevant studies are as follows:（1）Uniform deposition of Ag particles on polydopamine-modified woven carbon fibers was achieved by a simple in situ thermal reduction.This method saves the tedious production process,avoids the use of toxic and harmful substances,and realizes the green and simplicity of the fiber metallization process.Due to the reduction of catechol in PDA,the chelation with metal ions and the CF that through electrons transfer as intrinsic conductive substrate simultaneously promoted the reduction capability of PDA during the reduction process,make PDA trap Ag ions on the surface of carbon fiber and reduce them to Ag particles to grow firmly on the surface of carbon fiber.The material exhibits ultra-high conductivity and excellent EMI shielding effectiveness,and exhibits excellent electromagnetic shielding stability after taping.（2）Based on the three important roles of PDA（self-polymerization,reduction,and chelation with metal ions）for metal deposition on woven carbon fibers in the previous chapter,CF-PDA@Ag fibers were prepared.Since the interface design of composite materials is critical for the optimization of their mechanical properties.The CF-PDA@Ag prepared in the previous chapter was chosen as the skeleton with dimensional advantages,and the PPS resin with excellent overall performance was selected as the matrix to prepare multifunctional electromagnetic shielding composites by hot press molding method.Conductive network formed by Ag and woven carbon fibers,the material has a high electrical conductivity of51240.71 S/m and an electromagnetic shielding effectiveness of 52.9 dB.The in-situ interfacial reinforcement method induced by unique coordination and chelation reactions results in a material thickness of up to 368.45 MPa in room temperature tensile strength at only 0.4 mm,it also exhibits excellent tensile properties at low and high temperatures.Moreover,the CF-PDA@Ag/PPS composite exhibits excellent tribological properties,with a coefficient of friction as low as 0.28 and a wear rate of only 2.59×10^-5 mm³N^-1m^-1.The high efficient conductive network also provides excellent electrical heating performance for CF-PDA@Ag/PPS composites.The material can responds quickly to step changes in voltage and cyclic heating.During long-term electric heating,the temperature remains smooth and shows good long-term electric heating stability.Due to the excellent properties of PPS,it gives the material excellent flame retardant properties and solvent resistance.In addition,the material also shows excellent shielding stability after high temperature combustion and immersion in a variety of solvents.（3）Based on the previous chapter,PPS was mechanically mixed with Fe₃O₄ and prepared as PPS@Fe₃O₄ films.The CF-PDA@Ag/PPS@Fe₃O₄ composites were prepared by the same preparation process.The introduction of Fe₃O₄ in the composite enhances the magnetic loss in the incident direction of electromagnetic wave.When the electromagnetic wave is incident on the composite material,it goes through the process of"absorption-reflection-reabsorption"The electromagnetic shielding effectiveness of CF-PDA@Ag/PPS@Fe₃O₄ composite increases to52.34 dB while the reflectivity decreases from 0.96 to 0.86.