AUTHORS: Rodney Andrews, Terry Rantell, Francios Vilain, Apparao Rao, Frank Derbyshire
Center for Applied Energy Research, University of Kentucky, Lexington, KY;
Elizabeth Dickey, Dali Qian
Chemical and Materials Engineering, University of Kentucky, Lexington, KY
The discovery of carbon nanotubes has spawned a tremendous level of activity in carbon research, since the practical realization of their extraordinary properties can open numerous possibilities for new materials. Here we show that carbon nanotubes (both single wall -SWNT, and multi-wall -MWNT), when dispersed in isotropic pitch matrices, lead to nanotube-carbon composites and nanotube-reinforced carbon fibers with enhanced mechanical and electrical properties. We describe the synthesis and properties of carbon nanotube composites in the form of carbon fibers, sinters and thin carbon films produced via the addition and dispersion of nanotubes in an isotropic pitch precursor.
Composite fibers can be produced by extrusion in which it is possible that mechanical shear can be used to orient the nanotube bundles. For these materials, tensile strength and modulus of elasticity were measured for 0, 1 and 5 wt $\%$ nanotube loadings (both SWNT and MWNT) along with the electrical conductivity. Fibers could not be spun from the nanotube-pitch mixtures containing higher concentrations of nanotubes. The difficulties associated with dispersing the nanotubes in the pitch matrix, as well as the problem of spinning fibers from pitches at high MWNT loadings will be addressed with reference to the effect of MWNT addition on melt viscosity.
We will also describe the effects of nanotube addition on the physical properties of sintered carbon discs and thin carbon films. Given the apparent difficulty in spinning fibers with high nanotube concentrations, the direct production of nanotube-containing artifacts may prove to be a more productive field of investigation.