(275c) Improving the Electrical Conductivity of Polycarbonate Carbon Nanotubes Composites

Carbon Nanotubes’ (CNT) high aspect ratio and electrical conductivity (EC) make them ideal conductive fillers for polymers. However, in order to take full advantage of these properties, CNT need to be separated and dispersed evenly throughout polymer matrices. Current methods are either not commercially viable, inefficient, environmentally unfavorable, or severely damage the CNT. The primary goal of this project was to show that by using a super critical carbon dioxide (scCO2 ) expansion process, CNT could be deagglomerated before being melt blended in to the polymer matrix, leading to improved dispersion, EC, and percolation threshold.
It was found that for 3wt % multi-wall carbon nanotubes (Baytube C150 P) in polycarbonate samples treated with scCO2 showed a sixteen fold increase in surface conductivity (SC) from 3.1*10⁻⁶ S to 5.1 *10^-5 S. For 1wt % samples treated with scCO2, SC went from <10⁻¹⁰ S to 3.1*10 ⁻⁸ S. In addition to the conductivity tests, transmission electron microscopy was employed to examine the impact on the morphology of the samples.