Electrical and EMI shielding characterization of multiwalled carbon nanotube/polystyrene composites

Abstract

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. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40201.

Pre-localized MWCNT network for a low percolation threshold in MWCNT/ABS nanocomposites: experiment and theory

“…However, these approaches suffer from some limitations such as a difficulty in dispersion due to the viscosity of the polymer melts 15 and re-agglomeration of the nanotubes during the drying process. 18 Composites with networked MWCNTs are found to be much superior to the distributed MWCNTs (solution PS mixing) in terms of lower electrical resistivity and higher compressive strength. Conductive MWCNTs will remain localized at the interfacial place between the ABS particles in the absence of any shear, and hence build up a network of conductive pathways.…”

“…16,17 The preparation process of MWCNT/ABS composites in this work involves coating of a MWCNTs layer on the ABS particles and subsequent compacting by compression molding. 18 A stepwise schematic diagram of sample preparation is illustrated in Fig. The technique of sample preparation of the MWCNT/ABS nanocomposite is the same as used earlier.…”

Multifunctionalized Carbon Nanotubes Polymer Composites: Properties and Applications

“…By adding 1 wt% of MWCNTs to polystyrene, the elastic modulus and break stress increased by 36-42 and 25 %, respectively. The verification of the external load transfers to nanotubes was efficiently achieved by tensile tests and in situ transmission electron microscopy, showing that nucleation of cracks takes place at low-density area of CNTs, and after that, propagates along the poor CNT-polystyrene interfaces or relatively low CNT density regions (Kumar Sachdev et al 2013;Tang et al 2014). When the crack dimension exceeds 800 nm, CNTs start to break and/or even remove itself from the polystyrene matrix.…”

“…As mechanical properties play a crucial role in structural purposes, load transfer from the polymer matrix to CNTs filler grows to be essential. Load transfer between polymer matrix and CNTs is subject to the interfacial shear stress between the composite components (Kumar Sachdev et al 2013). To make the reinforcement efficient, it is required that the CNTs must be adequately long and the interface between CNTs and polymer matrix is strong (Xiaowen et al 2006).…”

“…This, in turn, disclosed the fact that aligned CNTs structure could not only improve hydrophobicity, but also give rise to a high adhesion force. The CNTs incorporated into the polystyrene matrix are applicable to the tire industry (Kumar Sachdev et al 2013).…”