A strategy to achieve high electromagnetic interference shielding and ultra low percolation in multiwall carbon nanotube-polycarbonate composites through selective localization of carbon nanotubes
By Maiti, Sandip; Suin, Supratim; Shrivastava, Nilesh K. & Khatua, B. B.
Published in RSC Adv.
The Royal Society of Chemistry
2014
Abstract
Here, we report a simple method that involves solution blending of polycarbonate (PC) in the presence of multiwall carbon nanotubes (MWCNTs) and commercial PC beads for the preparation of electrically conducting MWCNT-PC composites with high electromagnetic interference shielding effectiveness (EMI SE) and electrical conductivity at very low ([similar]0.021 wt%) percolation threshold (pc). Thus, electrical conductivity of [similar]4.57 [times] 10-3 S cm-1 was achieved in the MWCNT-PC composites at an extremely low MWCNT loading (0.10 wt%) in the presence of 70 wt% PC beads in the composites. Finally, optimizing the ratio of PC beads and MWCNT loading in the composites, a very high EMI SE value ([similar]23.1 dB) was achieved at low loading (2 wt%) of MWCNT with 70 wt% PC beads. The effective concentration of MWCNT increases in the solution blended PC region with increasing the amount of PC beads. Thus, a strong interconnected conductive network structure of CNT-CNT is developed throughout the matrix and the presence of strong [small pi]-[small pi] interaction among the electron-rich phenyl rings of PC and MWCNT in the composites plays a crucial role in increasing the EMI shielding value and electrical conductivity of the MWCNT-PC composites.