Effects of multi-walled carbon nanotube (MWCNT) type and flow type (shear and elongational flow) on the electrical conductivity of polycarbonate (PC)/MWCNT nanocomposites were investigated. Two different MWCNTs produced a huge difference in electrical conductivity in an injection molded PC/MWCNT nanocomposite. It was observed that MWCNTs having a higher aspect ratio provide much lower electrical conductivity in injection molded PC/MWCNT nanocomposites while the conductivities of compression molded samples from two different MWCNTs were the same. We found that this is due to a difference in the deformability of the two MWCNTs. Nanocomposite samples prepared at a higher extensional rate and shear rate showed lower electrical conductivity. This is attributed to flow induced orientation of the MWCNTs. The experimental results were discussed in relation to variation in the tube–tube contact due to the change of the MWCNT orientation.

Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Preparation of the nanocomposites
        2.3 Sample preparation and characterizations
    3 Results and discussion
    4 Conclusions
    Acknowledgements 
    References

• Kwan Han Yoon(Department of Chemical Engineering, Kumoh National Institute of Technology)
• Young Sil Lee(Industry‑Academic Cooperation Foundation, Kumoh National Institute of Technology)