Morphology of conducting filler-reinforced nitrile rubber composites by electrostatic force microscopy

An advanced technique of morphology observation of conducting filler-reinforced nitrile rubber composites by electrostatic force microscopy is reported. The composites were prepared by mixing carbon blacks and multi-walled carbon nanotubes with nitrile rubber. Increase in the voltage applied to the probe tip in electrostatic force microscopy enhanced clear visibility of carbon black particles and their distribution in the rubber matrix. The surface topography of the composite indicated the presence of carbon black aggregates having different size and structure depending on the type of carbon black. The electrostatic force microscopy images of carbon nanotube-filled composite clearly showed the presence of bundles of nanotubes embedded in the rubber matrix. The average diameter of nanotube bundles was found to be around 50 nm.