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

Abstract

Nanocomposites of well-dispersed multi walled carbon nanotubes (MWCNTs) in an acrylonitrile–butadiene–styrene (ABS) matrix were prepared by dry tumble mixing and a subsequent hot compression technique. The preparation method is analysed here to assist in the explanation and understanding of the experimental observations. The vision of the processing method has been confirmed using scanning electron microscopy. As a result of decent dispersion and pre-localization of MWCNTs in the ABS matrix, the electrical conductivity of the nanocomposite as a function of filler content exhibits a distinctive percolation behavior with a percolation threshold of only 0.0005 volume fraction. The high aspect ratio of MWCNTs enables the creation of interconnected networks within the ABS matrix at a very low nanofiller loading, while their high inherent electrical conductivity yields nanocomposites with a high bulk electrical conductivity. To explain the conductivity behaviour, statistical percolation theory and GEM theory are employed. The model parameters elaborated show that both models can adequately describe the behaviour. A comparative analysis of the applicability of percolation theory and GEM theory for expressing the conductivity behavior of the MWCNT/ABS composites with other research works has been performed. Finally, the electrical conductivity of MWCNTs based on the data in this work and elsewhere is evaluated. The universal exponent t is found to be 1.93 for a best-fit value of percolation threshold of 0.000485 vol. fraction of MWCNTs in this work. The D shore hardness results have revealed a random increase in hardness and density with an increasing MWCNT content.