Carbon nanotube - Polymer composites: A study on electrical conductivity

Polypropylene and bismaleimide were processed for electrically conductive applications. Pristine (P-SWNTs) and benzoyl peroxide (BP-f-SWNTs) in situ functionalized single-walled carbon nanotubes were used. The materials were prepared by high shear mixing and molded into sheets. Scanning electron microscopy and Raman Spectroscopy were used for nanotube and composite characterization. The electrical properties of the bulk samples were studied. Nanotube sidewall functionalization is known to diminish the electrical properties of the composite; however BP functionalization did not show a significant decrease in the electrical conductivity. The electrical resistivity of polypropylene was lowered by 15 orders of magnitude by incorporating 10 wt% pristine and only 6 orders magnitude using functionalized SWNTs. The percolation threshold of polypropylene composites was found to be 2.5wt% for P-SWNTs and 4wt% for BP-f-SWNTs. Preliminary studies on dispersion and surface coverage of carbon nanotubes on carbon fiber fabrics is also presented. These fabrics were coated with nanotubes using spray technology. The dispersion and surface coverage were characterized using optical microscopy, and scanning electron microscopy. Uniform surface coverage was observed which can provide a good network for electrical conduction. These fabrics were further used for processing of bismaleimide composites and the samples were tested for electrical conductivity.