Electromagnetic interference shielding effectiveness of ethylene vinyl acetate based conductive composites containing carbon fillers

Conductive polymeric based composites were derived from ethylene vinyl acetate rubber filled with Vulcan XC-72, short carbon fiber (SCF), and their blends. The electromagnetic interference (EMI) shielding effectiveness (SE), return loss, and reflection coefficient were studied. The measurements of the SE of the composites were carried out in two different frequency ranges of 100-2000 MHz and 8-12 GHz (X band). It was observed that the SE of the composites was frequency dependent and it increased with increasing frequency. The increasing of filler loading also enhanced the SE of the composites. The 100% SCF filled composites showed a higher SE compared to that of the filler blend or purely carbon black filled composites. The correlation between the SE and bulk conductivity of various composites was also discussed. The compromise between EMI SE, electrical conductivity, and mechanical properties was obtained when the composites contained both types of filler like particulate carbon black and SCF. (C) 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1601-1608, 2001.