Electromagnetic Interference (EMI) Shielding Effectiveness (SE) of Unsaturated Polyester Resin with Carbon Black Fillers

Abstract

This paper presents the electromagnetic interference (EMI) shielding effectiveness (SE) investigation of carbon black filled polyester composites. The composition of the polymer composite ranging from 4, 6, 8 and 10wt % of carbon black to unsaturated polyester resin was prepared. Two types of carbon black were used in this project, carbon black derived from water hyacinth and commercially available activated carbon black. The S (scattering)-parameters (S11 and S21) of polyester composites were measured and compared between the two types of carbon black; carbon black derived from water hyacinth and activated carbon black. The shielding effectiveness was determined from measured S11 and S21 parameters. It was observed that the shielding effectiveness of the composites is frequency dependent and filler loading dependent. According to the results, the contribution of absorption to shielding effectiveness of both carbon blacks is greater than 83 % at 3 GHz. The analyzed results showed that the percentage of shielding effectiveness of polyester composite reinforced with naturally derived carbon black is similar to those with activated carbon black. The result also showed that the contribution of absorption to the shielding effectiveness was larger than that of reflection. This research suggests that polyester composite with carbon black derived naturally from water hyacinth can be used as a replacement for the commercially available activated carbon black as a shielding material in medical applications.