Polypyrrole composites for shielding applications

This article highlights the physical properties of polypyrrole (PPy) coated over MnZn ferrite (MZF), nickel coated over PPy, and PPy coated over Ni-MZF magnetic core particles. The commercial ferrite and Ni-ferrite particles are primarily used, and the PPy-ferrite particles with composite structure are synthesized both via an oxidative polymerization of pyrrole in an aqueous solution, which contains well-dispersed ferrite particles, and electrochemical polymerization technique in acetonitrile (ACN). The materials have been processed in the form of coatings, films, and sheets by blending of conventional polymer such as polyurethane (PU) wherein the composites retain the mechanical properties of the conventional polymers and the electrical conductivity of the conducting polymers. The influence of ferrite content with respect to the electrical and ferromagnetic properties of PPy composites were investigated by electrochemical impedance spectroscopy (EIS) and dc field-cooled, zero-field cooled susceptibilities and M-H loop measurements. Their structural characterization is also discussed based on Fourier transform infrared (FTIR) and the X-ray diffraction (XRD) measurements. The shielding effectiveness (SE) properties will be reported in our future studies.