Study On The Preparation And Microwave Absorbing Property Of PANI/CIP Composite In Aqueous Solution Of Polyvinylpyrrolidone

The magnetic/polymer composite is a function material of a magnetic iron oxideparticles embedded in a polymer matrix material. In recent years, magnetic polymercomposite has been aroused great interest because it has broad application prospects inthe field of electromagnetic shielding, microwave absorption, electromagnetic induction.With high purity and permeability.carbonyl iron powder (CIP) qualified high pure、magnetic loss and a strong absorption of electromagnetic waves. But there aredisadvantages of high density and absorbing band narrow. Polyaniline (PANI) is one ofthe most extensively studied conductive polymer in microwave absorbing material dueto its low density, high conductivity, the dielectric loss and excellent environmentalstability.PANI and CIP inorganic magnetic particles are put together, we can control thematerial electric, magnetic properties and make up for the defects of a single material. Itis one of the ideal ways of the development of lightweight, broadband, high efficiencyelectromagnetic absorbing materials. However, the study found that magnetic particlesare prone to self-agglomeration and the complex particles are also easy to showscattered unevenly. As we knew, the core–shell structures show the microwaveabsorption better than the pure core or shell materials. Conductive polymer-CIPcomposites were the most extensively studied microwave absorbing material due totheir (in)organic advantages and inductance coupled characteristics. More, it is difficultfor PANI to fully cover the larger CIP aggregates composite and form of core-shellstructure of PANI/CIP of composite absorbent. In order to form core-shell structure ofPANI/CIP composite easily, polyvinylpyrrolidone (PVP) as a stabilizing dispersingagent is introduced into the reaction system to solve the problem of reunification andcoating of CIP, incompletely.Polyaniline/carbonyl iron powder (PANI/CIP) composite with core/shell structurewas synthesized via in situ polymerization in aqueous solution of polyviny-lpyrrolidon(PVP). The micromorphology, structure and microwave absorbing propertyof the composite were characterized by scanning electron microscope (SEM)、FourierTransform Infrared(FT-IR)、X-ray diffraction(XRD) and vector network analysis(VNA).And the modified mechanism of PVP on polymerization was discussed. The researchshowed that the present of PVP was conducive to not only dispersion of CIP but also the formation coated well and core/shell composite. PANI/CIP composite which wasdecorated by PVP has obviously improved on wave absorbing property compared withthe composite which was synthesized without PVP. Electro-magnetic parameters of thecomposite were determined at26.5—42GHz.The minimum reflection loss for compositewas improved16-dB and could reach35-dB, the frequency range for absorption valuereached6GHz which was increase of3times.