ABSTRACT
Carbon nanotubes (CNTs) are unique tubular structures of carbon with a few nanometer diameter and large aspect ratio. The structure and properties of CNTs are highly sensitive to the production method and synthesis parameters such as temperature, reactor size, gas flow and pressure, precursors. Scanning electron microscopy is used to determine the nature of the CNTs and obtain a rough idea about material quality. Compared to CNTs, the carbonaceous impurities usually have higher oxidation reactivity due to the presence of more dangling bonds and structural defects. Different morphology, aspect ratio, size, solubility, gravity, and magnetism of CNTs from those of impurities enable one to separate CNTs from impurities by using physical techniques such as filtration, chromatography, centrifugation, electrophoresis, and high-temperature annealing. For structural or load-bearing applications, the addition of CNTs to the polymer matrices can increase mechanical properties like stiffness, strength, and toughness significantly.
