Today, we stand at the edge of exploring carbon nanotube (CNT) and graphene based polymer nanocomposites as next generation multifunctional materials. However, irrespective of the methods of composite preparation, development of electrical conductivity with high electromagnetic interference (EMI) value at very low loading of CNT and (or) graphene is limited due to poor dispersion of these nanofillers in polymer matrix. Here, we demonstrate a novel technique that involves in-situ polymerization of styrene/multiwalled carbon nanotubes (MWCNTs) in the presence of suspension polymerized polystyrene (PS)/graphite nanoplate (GNP) microbeads, for the preparation of electrically conducting PS/MWCNT/GNP nanocomposites with very high (~20.2 dB) EMI shielding value at extremely low loading of MWCNTs (~2 wt %) and GNP (~1.5 wt %). Finally, through optimizing the ratio of PS-GNP bead and MWCNTs in the nanocomposites, an electrical conductivity of ~9.47 × 10(-3) S cm(-1) was achieved at GNP and MWCNTs loading of 0.29 and 0.3 wt %, respectively. The random distribution of the GNPs and MWCNTs with GNP-GNP interconnection through MWCNT in the PS matrix was the key factor in achieving high electrical conductivity and very high EMI shielding value at this low MWCNT and GNP loadings in PS/MWCNT/GNP nanocomposites. With this technique, the formation of continuous conductive network structure of CNT-GNP-CNT and the development of spatial arrangement for strong π-π interaction among the electron rich phenyl rings of PS, GNP, and MWCNT could be possible throughout the matrix phase in the nanocomposites, as evident from the field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) studies.

Here, we demonstrate an easy method for the preparation of highly electrically conductive polycarbonate (PC)/multiwalled carbon nanotubes (MWCNTs) nanocomposites in the presence of poly(butylene terephthalate) (PBT). In the presence of MWCNTs, PC and PBT formed a miscible blend, and the MWCNTs in the PC matrix were uniformly and homogeneously dispersed after the melt mixing of the PC and PBT-MWCNT mixture. Finally, when the proportion of the PC and PBT-MWCNT mixture in the blend/MWCNT nanocomposites was changed, an electrical conductivity of 6.87 Â 10 À7 S/cm was obtained in the PC/PBT-MWCNT nanocomposites at an MWCNT loading as low as about 0.35 wt %. Transmission electron microscopy revealed a regular and homogeneous dispersion and distribution of the MWCNTs and formed a continuous conductive network pathway of MWCNTs throughout the matrix phase. The storage modulus and thermal stability of the PC were also enhanced by the presence of a small amount of MWCNTs in the nanocomposites.

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Abstract. In this work, polycarbonate (PC)/multiwall carbon nanotube (MWCNT) nanocomposites were prepared by simple melt mixing at a temperature (~350°C) well above the processing temperature of PC, followed by compression molding, that exhibited percolation threshold as low as of 0.11 wt% and high electrical conductivity of 1.38!10 -3 S·cm -1 at only 0.5 wt% MWCNT loading. Due to the lower interfacial energy between MWCNT and PC, the carbon nanotubes are excellently dispersed and formed continuous conductive network structure throughout the host polymer. AC electrical conductivity and dielectric permittivity of PC/MWCNT nanocomposites were characterized in a broad frequency range, 10 1 -10 7 Hz. Low percolation threshold (p c ) of 0.11 wt% and the critical exponent (t) of ~3.38 was resulted from scaling law equation. The linear plot of log! DC vs. p -1/3 supported the presence of tunneling conduction among MWCNTs. The thermal property and storage modulus of PC were increased with the incorporation of little amount of MWCNTs. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) confirmed the homogeneous dispersion and distribution of MWCNTs throughout the matrix phase.

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