The preparation and investigation of electromagnetic interference (emi) shielding properties of poly(ethylene)terephthalate/ polypyrrole compozites

In this study, a composite material was prepared for electromagnetic interference (EMI) shielding purposes, via chemical polymerization of polypyrrole (PPy) on polyethylene terephthalate (PET) sheet. PET layer provides flexibility and long term stability, as the PPY film provides electrical conductivity and good absorptivity against EM radiation. This type of composite material offers non-corrosive property, light-weight and cost efficiency when compared to regularly used metallic EMI shielding materials. Since, the synthesis conditions govern the electrical conductivity of resulting conductive polymer film, PPy synthesis was studied in a series of acid solutions. The electrical conductivity of composite materials was measured with four probe method. In order to obtain an effective EMI shielding material, the conductive film should have high surface coverage and extremely small pore size as much as possible. For this reason, the surface morphologies were investigated and various etching processes were applied on the PET film surface. The surface coverage ratio was improved to 99.84% and maximum pore size was reduced to 18 μm. EMI shielding performances were examined in the IR region of the electromagnetic spectrum and the protective effectiveness (SE) value was determined in dB.