### Basic Methods for the Synthesis of Carbon Nanotubes  
The main modern methods for the synthesis of CNTs are the discharge arc method and methods of deposition from liquid or gaseous media using organometallic catalysts [78; 79]. In the discharge-arc method, carbon particles are removed from the graphite electrode in an inert gas flow in an arc discharge plasma and deposited in the form of honeycomb structures on the cathode surface. In this case, mainly MWCNTs are obtained. The method of deposition of CNTs from liquid media (for example, acetone, alcohol) is the decomposition of a mixture of a carbon-containing compound and a catalyst (iron acetates, cobalt acetates) in an argon flow at temperatures of 600-800 \({}^{\circ}\)C. It is possible to obtain SWCNTs in the resulting soot with a low yield. When obtaining nanotubes from the vapor phase (CVD method), a hydrocarbon (methane, ethylene, acetylene) is passed over a metal-containing catalyst at temperatures of 500-800 \({}^{\circ}\)C. The method is widely used but has several drawbacks, including the need to maintain high temperatures, as well as the low yield of nanotubes. One of the most promising methods for the formation of structures with a developed surface morphology is metalorganic chemical vapor deposition (MOCVD) using volatile organometallic compounds (metallocenes) and hydrocarbon precursors [80; 81]. The use of this method makes it possible to avoid catalyst passivation and makes the pyrolysis process almost continuous. In the world, among the variety of methods for synthesizing CNTs, the MOCVD technology is the most widespread [82; 83].  
An important stage in the control of chemical properties is the CNTs' functionalization. In composites and other systems, an important role is played by the uniform distribution of nanotubes over the matrix bulk. The high tendency of nanotubes to form clusters, so-called agglomerations, containing up to several hundred CNTs, creates significant difficulties in their dispersion into the material matrix. CNT agglomerations can take the form of a bundle, a bundle, a coiled ball, and so on [22]. Most of the works on the preparation of composite materials with polymer [84; 85], metal [86; 87; 88; 89; 90; 91], and ceramic [92; 93] matrices contain results confirming the expediency of the decision to apply additional processing (functionalization) of CNTs for the purpose of chemical grafting of polar groups to the surface. This treatment makes it possible to obtain a more stable dispersion medium in polar solvents, increase the chemical activity of the surface, and increase the bond with the matrix [21; 94]. The most common are oxidative functionalization methods with the formation of oxygen-containing groups covalently bonded to the CNT surface-carboxyl, hydroxyl, aldehyde, ether, ketone, anhydride, lactone (-OH, -C=O, -COOH) [94; 86; 95; 96; 97; 98; 99]. At the same time, functionalization by oxidation often leads to a decrease in some of the tubes: a decrease in their diameter and length, opening of the ends, and to the appearance of carboxylated fragments on the side surfaces. Thus, their high physical and mechanical characteristics, low density, and nanosized particles make CNTs a promising reinforcing component.