Potential of carbon nanotubes for developing materials far lighter and stronger than today's materials

摘要

Single wall, double wall, and multiwall carbon nanotubes (CNT), as well as vapor grown carbon nano fibers are being dispersed in various polymer matrices by insitu polymerization, in melt, and in solution. Matrix system studied to-date include poly(p-phenylene benzo bis-oxazole) (PBO), polypropylene (PP), poly (vinyl alcohol) (PVA), poly(methyl methacrylate) (PMMA), and polyacrylonitrile (PAN). These composite systems have been extruded into continuous fibers by conventional melt and solution spinning technologies. Improvement in fiber properties include enhanced tensile strength, modulus, chemical resistance, increased glass transition temperature, and reduced thermal shrinkage. Carbon nanotubes also act as nucleating agent for polymer crystallization. For enhancing nanotube dispersion, oxidized and functionalized nanotubes are also being used. PAN orientation is higher in PAN/CNT composite and PAN/CNT fiber exhibit up to 50% reduction in thermal shrinkage as compared to the control PAN fiber processed under the same conditions. These and other structural and property data suggest that PAN/CNT would be a precursor for next generation carbon fiber with improved strength and modulus. Carbon nanotubes and polymer/carbon nanotube films are being processed with unique combination of tensile strength, modulus, electrical conductivity, dimensional stability, low density, solvent resistance, and thermal stability. Nanotubes and polymer/carbon nanotube composite films with and without carbonization and activation are also being evaluated for electrochemical supercapacitor electrodes. Results of these studies will be presented with a focus on developing next generation carbon fiber.