Shielding effectiveness of carbon-filled polycarbonate composites

In this project, varying amounts of three different carbons [carbon black (CB), carbon nanotubes (CNT), and graphene nanoplatelets (GNP)] were added to polycarbonate (PC). The resulting single filler composites were tested for shielding effectiveness (SE). The effects of single fillers and combinations of two different carbon fillers were studied via a factorial design. At the highest single filler loadings, the following SE results were obtained at 800 MHz: 18.9 dB for 10 wt % CB/PC, 18.4 dB for 8 wt % CNT/PC, and 6.3 dB for 15 wt % GNP/PC. The highest SE value of 21.4 dB was measured for the 5 wt % CB/5 wt % CNT/PC composite and could be used in SE applications (typically\u3e 20 dB is needed). Statistically significant equations were developed that could be used to predict the SE of composites containing these fillers. In addition, it was determined that the composite SE is higher than what would be expected from the additive effect of each single filler for the CB/GNP/PC composites