Magnetic property measurements on single wall carbon nanotube polyimide composites

Magnetization measurements as a function of temperature and magnetic field were performed on polyimide nanocomposite samples containing various weight percentages of single wall carbon nanotubes. It was found that the magnetization of the composite, normalized to the mass of nanotube material in the sample, decreased with increasing weight percentage of nanotubes. It is possible that the interfacial coupling between the carbon nanotube (CNT) fillers and the polyimide matrix promotes the diamagnetic response from CNTs and reduces the total magnetization of the composite. The coercivity of the samples, believed to originate from the residual magnetic catalyst particles, was enhanced and had stronger temperature dependence as a result of the composite synthesis. These changes in magnetic properties can form the basis of a new approach to investigate the interfacial properties in the CNT nanocomposites through magnetic property measurements. (C) 2008 American Institute of Physics.