Carbon nanotubes due to unique properties have various applications. CNTs tend to agglomerate due to their hydrophobic surface. Hence, CNTs surface are modified with functional groups to better dispersion in solvents and polymers. To remove produced impurities during the CNTs synthesis, purification of CNTs is needed before functionalization. CNTs are purified by chemical and physical methods. Physical methods purification is not complete, so physical purifications are used with some chemical methods. Chemical purifications lead to functionalization of CNTs. Functionalization methods of CNTs are categorized into covalent and noncovalent methods. Chemical oxidation is the most common method to generate oxygen containing functional groups. Some parameters such as temperature, time, type and concentration of oxidants and oxidation method affect on the functional groups on the CNTs. In this study, methods of purification and functionalization of CNTs and factors affecting CNTs oxidation are examined based on the results presented in scientific literature.
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