Electrical and EMI Shielding Characterization of Multiwalled Carbon Nanotube/Polystyrene Composites

The electromagnetic interference (EMI) shielding mechanism of carbon nanotube (CNT)/polymer nanocomposites synthesized through a unique processing technique has been studied. As CNT/polymer nanocomposites evolve towards device applications, homogenous dispersion of CNTs has become a main objective to realize their full potential. In this work, dispersion of multi-walled carbon nanotubes (MWCNTs) in polystyrene (PS) powder via dry state tumble mixing has been carried out. This involves the coating of the PS particles with the MWCNTs. Pellets were prepared by hot compression of resulted mixture. Conductivity behavior has shown that an extremely small mass fraction of 0.05 wt % MWCNTs in PS is good enough for percolation threshold. A detailed study of EMI shielding behavior of these composites is reported in addition to physical phenomena involved. The shielding effectiveness achieved is higher compared to solution mixing technique used by others. Decrease in hardness with increase in MWCNT content is little. Scanning electron microscope studies of these nanocomposites revealed a web/mesh like structure consisting of MWCNTs. (C) 2013 Wiley Periodicals, Inc.