Study On The Preparation And Electromagnetic Proprties Of Substituted Polyaniline And Substituted Polyaniline/Zn_0.6Mn_0.2Ni_0.2Fe₂O₄ Composites

In the recent years,the synthesis of conductive polymers with the magnetic behavior and the magnetic nano-particles including conductive polymers has attracted people great attentions.Among the whole conducting polymers,polyaniline(PAn) has a specific situation because of its simply synthesis,environmental stability,low price,light mass and doping with protonic acids and can be widely used in such fields as antistatic conductive,microwave absorption,electromagnetic shielding and so on.However,the major disadvantage of PAn is its insolubility in common organic solvents and its infusibility because of the strongÏ€conjugate action.There are some possible methods for preparing soluble PAns.One of these methods is to substitute one or more hydrogens by an alkyl,an alkoxy,an amino group,or halogen on the benzene ring or -N atom.Different substituted anilines have different properties and they can remedy the defects of polyaniliane.So compounding the polyaniline or poly substituted-aniline with ferrite by proper ways will provide the composites a better comprehensive performance and the original characteristic of constituents be kept.Adjusting the composition of composites has an effect on the electromagnetic properties of composites and can make up for the deficiency of single component ferrite and polymers.So this method brought the more vast development space for the practical application of electromagnetic materials.Desiring the above purposes,we prepare the substituted polyaniline and substituted polyaniline/Zn_0.6Mn_0.2Ni_0.2Fe₂O₄ composites and wish to improve the electromagnetic loss properties of composites under the premise of widen their application range.In this article,the Zn_0.6Mn_0.4-xNixFe₂O₄(x=0.1,0.2,0.3,0.4) magnetic particles were prepared by the chemical coprecipitation and the Zn_0.6Mn_0.2Ni_0.2Fe₂O₄(ZMNF) was used to prepared composites.The copolymers(aniline-co-2chloroaniline) (PAn-co-P2ClPAn),poly(o-methylaniline)(POT),poly(N-methylaniline)(PNMAn), polyaniline(PAn) and their composites(polymer/ZMNF) with different ZMNF mass fraction were synthesized by in-situ aqueous polymerization.The structure of samples was characterized by X-ray diffraction(XRD) Fourier transform infrared spectra(FT-IR),and the particle sizes and morphologies of samples were observed by transmission electron microscopy(TEM) and scanning electron microscopy(SEM).The thermal stability of samples was measured by thermogravimetric analysis(TANA).The results revealed that the ferrite particles were wrapping well by polymers and form the core-shell structure,and the incorporation of ferrite improved the thermal stability of composites.The conductivity,saturation magnetization and electromagnetic loss parameters (tanδ_m,tanδ_e) of samples were measured.The results indicated that the conductivity of composites decreased with reduction of the conducting polymer content.The reason is that the continuity and doping degree of plymers decrease with the increase content of the hardly insulating ZMNF.The saturation magnetization decreases were lower than that of pure ferrite,and decreased with decreasing of ZMNF content.Moreover their coercive force was very little.In addition,the results showed that the tanδ_m decrease with the decreasing of ZMNF content,which was related to the volume fraction of ferrite particles.The results showed tanδ_e in some composites was larger than pure polymers,which applied a coordinate effect occurred between polymers and ZMNF particles.This indicated that the composites exhibited the strong interfacial polarization between polymers and ZMNF particles.And the interfacial interaction changed with the content change of polymers.