Preparation And Electromagnetic Properties Of Polypyrrole/Poly(N-Methylpyrrole)/Barium Ferrite Nanocomposites

Functional polymers has been one of the hotspots in current study,due to their good electrical,magnetic,catalysis properties and Biological Activity.Recently, electrical-magnetic properties polymer composites have attracted great attention. Poly(N-methylpyrrole)(PNMPy)/polypyrrole(PPy) have been extensively studied because of their adjustable conductivity,good environment stability and relatively easy preparation. Owing to low price combined with reasonable magnetic performance,barium hexaferrite (BaM) powders,BaFe₁₂O₁₉,with magnetoplumbite structures have aslo been intensively investigated.It was necessary to prepare excellent electrical-magnetic properties polymer composites combining the merits of the inorganic magnetic materials and the organic polymers.A series of polypyrrole were synthesized by in-situ polymerization in different reaction conditions,in order to find best reaction condition.The BaFe_11.5Cr_0.5O₁₉ ferrite doped with different content of La and Nd were obtained by the citrate precursor sol-gel method;Ba_0.9Nd_0.1Fe_11.5Cr_0.5O₁₉(Abbreviated as BNFCO) with good magnetic property was chosen as magnetic core to prepare Polypyrrole/Ba_0.9Nd_0.1Fe_11.5Cr_0.5O₁₉((PPy/BNFCO) and poly(N-methylpyrrole)/polypyrrole/Ba_0.9Nd_0.1Fe_11.5Cr_0.5O₁₉(PNMPy/PPy/BNFCO) composites with different ferrite contents by in situ polymerization method.The microstructure,micromorphology and thermal stability of all the nanocomposites are characterized by Fourier transform infrared spectra(FT-IR),XRD,TEM,SEM and thermogravimetric analysis(TGA),respectively.XRD analysis revealed that the nanocomposites were composed of the conducting polymer and ferrite nanoparticles,and incorporation of ferrite particles had the influence on the crystallinity of conducting polymer.The results of SEM and TEM indicated that composites had obvious core - shell structure and the ferrite particles had a nucleus effect on the polymerization of aniline/pyrrole.FT-IR and TGA proved the formation of composites and confirmed that there was interaction between ferrite particles and polymer chains.Conductivity of samples was measured by the four-point probe technique.The magnetic properties of PPy/BNFCO and PNMPy/PPy/BNFCO composites were measured at room temperature under applied magnetic field by using a vibrating sample magnetometer(VSM).The electromagnetic loss properties of PPy/BNFCO and PNMPy/PPy/BNFCO composites were measured by the Impendence/Materials analyzer in the 1 MHz～3 GHz ranges.The results show that the magnetization and conductivity of the composites increased with increase of BNFCO and PPy contents,respectively.The magnetic loss was dominant for PPy/BNFCO and PNMPy/PPy/BNFCO composites,and the ability of magnetic loss improves with the content of magnetic particles increase.The PNMPy/PPy/BNFCO composites not only hold the excellent magnetic loss properties,but also improve the electronic loss properties obviously.And the ability of electronic loss increases with the PNMPy content.