Effects of tube diameter and state of dispersion on electrical properties of multi-walled carbon nanotube/natural rubber composites

Abstract

This paper reports changes in the electrical conductivity of multi-wall carbon nanotube/natural rubber (MWNT/NR) composites as a function of nanotube loading and nanotube diameter (φ). The percolation threshold of the φ13 nm MWNT/NR composite was found at a filler content of 2.9 wt%. A volume resistivity of a few 10⁻² Ωm was obtained at 16.7 wt% of φ13 nm MWNTs, which is almost half the 37.5 wt% needed for φ67 nm MWNTs. It has been found that the electrical resistivity depends little on the shape of the MWNTs based on the two-dimensional models of electrical path for the straight and round MWNTs. Since the good mechanical properties of thin MWNT/NR composites at 120 °C have already been reported, it would be expected that the application of these composites might be broaden.