Elastomer-carbon nanotube composites

Different techniques to disperse multi-walled carbon nanotubes (MWCNT) in elastomers using an internal mixer are applied and the physical properties of the resulting composites are evaluated. It is demonstrated that the dispersion can be improved if the CNT are suspended in a liquid agent in a first step to break up the bonds. Here, ethanol proved to be a good dispersion agent without any additional surfactant and could be vaporized during the mixing process. These investigations are extended to technologically more relevant filler hybrid systems, where parts of the reinforcing filler are exchanged by CNT. Additionally, the use of ionic liquids for improved CNT-polymer interaction is discussed. The dielectric properties, electrical DC conductivity, thermal diffusivity, dynamic-mechanical as well as the stress-strain and fracture mechanical behavior of CNT-filled composites are investigated. The effect of nanoscopic gaps between adjacent CNT on the electrical and thermal conductivity of the composites and the missing percolation behavior of the thermal conductivity are discussed.