The effect of mixing process on linear viscoelastic and electrical properties of ABS/MWNT nanocomposites

The aim of this article was to study the microstructure development and the linear melt viscoelastic properties of ABS/MWNT nanocomposites. The nanocomposite samples varying in nanotube concentration (1, 2, 4, and 8 wt %) were prepared using two different methods; solution method and direct melt compounding. Results of the melt linear viscoelastic measurements performed on the nanocomposite samples prepared by both methods showed a pronounced low frequency nonterminal behavior in storage modulus along with the viscosity upturn with greater extent for the samples prepared by the solution method. The values of low frequency storage modulus for the solution processed samples were found to be increased with increasing the nanotube content up to 3 wt % above which it is increased more significantly. These results could be related to a 3D microstructure development, the extent of which was found to be enhanced in the samples prepared by the solution method due to the improving interfacial interaction and promoting the nanotube dispersion in ABS matrix. This was supported by the SEM results of the samples. Dynamic mechanical thermal analysis results of the melt-mixed and solution-processed samples showed that Tg of the SAN is increased about 20 degrees C at the presence of nanotube. The results are related to the chain mobility restrictions caused by physical interaction between carbon nanotubes (CNT) and polymer chains. The electrical conductivity versus CNT content for the nanocomposite samples prepared by solution method showed a percolation behavior with CNT concentration above 4 wt % which attributed to the 3D network between nanotubes. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012