The EMI shielding effectiveness of PC/ABS/nickel-coated-carbon-fibre composites

The aim of this investigation is to prepare polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS)/nickel-coated-carbon-fibre (NCF) conductive composites possessing electromagnetic interference (EMI) shielding effectiveness (SE). A series of PC/ABS/NCF composites were prepared by the melt blending method. The various compositions of PC/ABS were 90/10, 70/30, 50/50, 30/70 and 10/90 percent by weight. The results indicate that the processability of PC/ABS/NCF could be improved by increasing the ABS content and that the mechanical strength of PC/ABS/NCF could be enhanced by adding NCF. Adding a higher amount of ABS in the PC/ABS/NCF composite could markedly improve the processability of the composites effectively. The NCF mean fibre length of PC/ABS/NCF also increased with increasing amounts of ABS. The best EMI shielding effectiveness of all PC/ABS/NCF is about 47 dB. However, for the reason of phase separation between PC and ABS, the oxygen could diffuse into the PC/ABS matrix and then reacted with Ni to form oxides little by little as heat treatment. As the oxidized layer on the filler increases the specific resistance, the EMI SE values markedly decrease with increasing heat treatment time. (C) 2000 Elsevier Science Ltd. All rights reserved.