On the influence of nanotube properties, processing conditions and shear forces on the electrical conductivity of carbon nanotube epoxy composites

• Published in: Nanotechnology Vol. 20; no. 15; p. 155703
• Main Authors: Kovacs, Josef Z, Mandjarov, Roman E, Blisnjuk, Thomas, Prehn, Kirsten, Sussiek, Martin, Müller, Jörg, Schulte, Karl, Bauhofer, Wolfgang
• Format: Journal Article
• Language: English
• Published: England IOP Publishing 15.04.2009
• ISSN: 0957-4484; 1361-6528; 1361-6528
• DOI: 10.1088/0957-4484/20/15/155703

We analyse statistical and kinetic percolation thresholds and maximum electrical conductivities of carbon nanotube epoxy composites as a function of shear forces, processing conditions, nanotube type and dimensions. Entangled and non-entangled nanotubes of different lengths (15-100 microm) and thicknesses (12-80 nm) have been obtained with three different synthesis methods based on catalytic or plasma enhanced chemical vapour deposition. The dispersions were processed either solely with a dissolver disk or additionally with a three roll calender. Care was taken to prevent unintentional shearing (e.g. through convection) in all samples that were not subject to deliberate shearing. It was found that shear forces have a similar influence on kinetic percolation thresholds and composite conductivities independent of nanotube types and dimensions.