Low percolation threshold in melt-blended PC/MWCNT nanocomposites in the presence of styrene acrylonitrile (SAN) copolymer: Preparation and characterizations

A simple method for the preparation of highly electrically conductive polycarbonate (PC)/styrene acrylonitrile (SAN)/multi-wall carbon nanotubes (MWCNTs) nanocomposites with extremely low loading of MWCNTs loading through melt-blending of PC and SAN-MWCNT has been reported. PC and SAN formed immiscible blend both in the absence and presence of MWCNT. The MWCNTs in the SAN phase were well dispersed after melt-mixing of PC and SAN-MWCNT mixture and formed a continuous conductive interconnected network structure throughout the matrix. This phenomenon is well known as double percolation. Finally, through optimizing the ratio of PC and SAN-MWCNT in the nanocomposites, electrical conductivity of 1.38 x 10(-5) S cm(-1) was obtained at MWCNTs loading as low as approximate to 0.35 wt%. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) showed that MWCNTs were homogeneously dispersed and distributed in the SAN phase and developed a continuous conductive interconnected network pathway throughout the matrix. Storage modulus and thermal stability of the PC in the nanocomposites were also improved in the presence of small amount of MWCNTs. Further study of the nanocomposites showed its enhanced electrochemical properties. (c) 2013 Elsevier B.V. All rights reserved.