Nanostructured carbon materials, such as graphene, oxidized graphene, and graphene oxide doped with nitrogen and sulfur heteroatoms, have specific physicochemical properties and can be used in various fields from electronics to medicine. Formed carbon nanoparticles are difficult to dope (especially oxidized graphene or graphene oxide) in such a way that they retain their structure as a whole. Therefore, it is promising to obtain precursors of these nanoparticles that are already doped with the desired heteroatom. Rolled or pressed materials from expanded graphite (EG) can be a precursor for obtaining such nanoscale materials by anodic exfoliation in electrolytes. Therefore, the development of methods for the synthesis of EG containing nitrogen and sulfur heteroatoms is the goal of this work. The paper deals with the synthesis and study of the physicochemical properties of graphite intercalation compounds (GICs) formed by their interaction with concentrated nitric and sulfuric acids, as well as their mixtures in various ratios. The main characteristics of the resulting GICs were determined and their capability to expand thermally was examined. It was shown that GICs with sulfuric acid have a better ability to expand and allow obtaining better quality EGs. EG samples obtained from these GICs were characterized by X-ray photoelectron spectroscopy (XPS) and derivatography. It was determined that during thermal expansion of co-intercalated graphite compounds, nitrogen and sulfur atoms are incorporated into the graphene planes of EG particles. It was shown that this method can be used to obtain EG doped with sulfur heteroatoms (0.2–0.5 at. %) mainly in sulfite and sulfate groups and nitrogen (0.6–1.2 at. %) mainly in the pyrrolic and quaternary chemical states, the content of which can be regulated by changing the ratio of sulfuric and nitric acids in the intercalating mixtures.

It has been experimentally shown that thermomechanical processing of polyamides in an oxidizing environment (in air) leads to structural degradation and loss of mechanical characteristics of the polymer. Reinforcement of polyamides PA6, PA6.6, PA12 with a nanosized carbon filler (carbon nanotubes (CNTs) and graphene nanoparticles) in small quantities (up to 0.5

Carbon materials with a graphite-like structure have the highest thermal stability in a non-oxidizing environment, sufficient structural strength, are easily processed, etc., and therefore they are widely used in various fields of technology. There are two methods of obtaining such materials: pyrolysis or carbonization of hydrocarbons and processing of natural graphite, so-called “thermo-expanded graphite technology” (TRG), which consists of successive reactions of intercalation, hydrolysis and heat treatment of natural graphite, leads to modification of the surface of TRG particles and provides the ability to their pressing and rolling on rollers to form dense materials. Natural graphite with a carbon content of 99.0–99.5 % by mass is used for the production of TRG, from which sealing materials are obtained for the equipment of enterprises of general industrial purpose: the fuel and energy complex, the petrochemical industry, utilities, etc. In the equipment of nuclear power plants, materials from TRG, of so-called “atomic purity”, are used, in which the carbon content must be at least 99.85 % by mass. Therefore, the purpose of the work is to obtain thermally expanded graphite of high purity by the method of electrochemical oxidation and further purification of flotation-enriched graphite. The production process took place in two stages: electrochemical intercalation of graphite with concentrated sulfuric acid followed by hydrolysis, and chemical further purification using ammonium bifluoride and Trilon B as cleaning reagents. Combining into one process of electrochemical oxidation of graphite and its further purification allows obtaining high purity TRG with a carbon content of 99.94–99.96 % by mass. In order to find the regularities of the interaction of Trilon B with metal ions included in the composition of graphite impurities, quantum chemical modeling of these processes was carried out. The energy effect of the interaction of the iron (III) cation is greater in absolute value (–969.1 kJ/mol) than for the case with the aluminum cation (–748.3 kJ/mol) both in the aqueous medium and in the adsorbed state on the surface of the graphene plane (–816.9 for Fe3+ and –621.2 kJ/mol for Al3+). Regardless of the nature of the cation, its interaction with Trilon B is thermodynamically more likely in an aqueous solution than in an adsorbed state on the surface of a graphene-like plane.

The purpose of this study was to determine the effect of carbon nanotubes (CNTs) on the thermal decomposition and thermo-oxidative destruction of nanocomposites based on polyester resin with a content of 0.1, 0.3 and 0.5 % by weight of CNT as characteristics of their heat resistance. Determination of thermal decomposition products, activation energy of their desorption, total amount of volatile decomposition products of composites was determined by the method of thermoprogrammed desorption mass spectrometry (TPDMS). Using derivatography methods (Q 1500D), patterns of thermo-oxidative destruction of polymer composites were investigated. It is shown that the addition of 0.1 wt. % CNT in the resin shifts the temperatures of the maximum thermograms (Tm) to higher values, increases the activation energy of desorption of all fragments of destruction products in the range m/z 18–104, compared to the original resin, i.e. this indicates an increase in the thermal stability of this composite. Increasing the CNT content to 0.3, 0.5 % by weight shifts Tm towards lower values, significantly reduces the activation energy of desorption for almost all polymer fragments. If at a content of 0.1 wt. %, CNTs in the polymer matrix are structurally “ordered” according to possible mechanisms, then an increase in the content of CNTs, on the contrary, leads to a reversible effect, due to the relatively large content of CNTs, their insufficient deagglomeration and uneven distribution. Thermo-oxidative degradation of unfilled resin has two characteristic minima at T = 383 °C and 439 °C (endothermic reactions of thermo-oxidative decomposition). The addition of CNTs in the amount of 0.1, 0.3, 0.5 wt. % shifts the temperatures towards higher values. Samples melt up to 385 °C followed by combustion with maximum temperatures at 443 and 534 °C. Probably, the presence of the second peak (534 °С) indicates the possibility of the formation of a certain percentage of a more ordered phase in the polymer. Thermooxidative decomposition of composites is characterized by an increase in the initial temperatures of phase transitions. This is probably due to the presence of a carbon nanofiller in the polymer matrix, which increases the heat capacity and thermal conductivity of the composite, possibly initiating crosslinking centers of free (unbound) polymer chains, which, in turn, causes a decrease in kinetic mobility in the polymer.

The purpose of the work is to establish the possibility of obtaining expanded graphite of high purity (carbon content more than 99.5 % wt.) from flotation-enriched graphite (carbon content 94–97 % wt.) by combining into one process intercalation of graphite with a solution of potassium dichromate in concentrated sulfuric acid with subsequent hydrolysis, and chemical purification using solutions of ammonium bifluoride in sulfuric or hydrochloric acid and Trilon B in an alkaline buffer as purification reagents, and to confirm this possibility by quantum chemical calculations. It has been experimentally shown that combining oxidized graphite synthesis and its chemical purification into one process allows obtaining expanded graphite of high purity, with a carbon content of 99.75–99.85 % wt. The methods of X-ray diffraction and thermogravimetry show that the interaction of oxidized graphite (the residual compound of intercalation of graphite with sulfuric acid) with cleaning reagents does not reduce the ability to expand. The magnitude of the mass loss of oxidized graphite according to various variants of chemical post-cleaning and the temperature range of such loss remain practically unchanged. Quantum chemical calculations of the adsorption energy (∆Eads) of one molecule of Trilon B on the surface of a graphene-like plane (GLP), the complexation reaction of metal sulfates, the energy effect of the interaction of Trilon B with sulfates of alkaline earth metals in an aqueous solution, and with the participation of the surface of the graphene plane were carried out using the GAMESS (US) program by the density functional theory (DFT) method with the B3LYP functional and the 6-31G(d,p) basis set, taking into account the Grimme D3 dispersion correction within the PCM polarizable continuum. The results of the analysis of quantum chemical calculations indicate that the Trilon B molecule is better physically sorbed on the oxidized GLP (–412 kJ/mol) than on its native form (–188 kJ/mol). The values of the energy effect of the complexation of magnesium and calcium cations with Trilon B have a negative value both in an aqueous solution and in the presence of the oxidized form of GLP. This indicates the thermodynamic probability of this process, which is consistent with the experimental results. Regardless of the nature of the cation, its interaction with Trilon B is thermodynamically more likely in an aqueous solution than in the adsorbed state on the surface of oxidized GLP.

The purpose of this work was to investigate the interaction of graphene-like nanoclusters with fragments of polymers of the same nature, but of a slightly different structure, for example, polyethylene (PE) and polypropylene (PP), experimentally and using quantum chemistry methods. It is experimentally shown that the reinforcement of PE and PP with carbon nanotubes (CNTs) by mixing in the melt, previously distributed from a stable aqueous dispersion on the surface of the polymer powder, leads to a change in structural, mechanical and thermodynamic characteristics.The degree of crystallinity changes, and the coherent scattering domain (CSD) size, the fracture stress increases, the fracture deformation, thermodynamic characteristics change, and such changes in characteristics for the PP-СNTs system prevail in comparison with the PE-CNTs system. The interaction energy of graphene-like fragments with PE and PP oligomers was calculated. It was established that the energy of interaction of a graphene-like nanocluster with a PP oligomer is greater, compared to PE, which is consistent with experimental data on the melting temperatures of pure polymers and polymer composites with nanotubes. The polymer with the surface of the nanocarbon fragment forms an intermolecular complex that is not covalently bound but is held by intermolecular dispersion forces.

The sheet samples of thermally exfoliated graphite (TEG)–carbon nanotubes (CNT) composites (TEG-CNT-cs) were obtained by persulphate oxidation using chemical (CO) and electrochemical (anode) oxidation (ECAO). Electron microscopy reveals multi-layered structures of few-layer graphene nanosheets with folded and tubular-like fragments. The effective thermal diffusivity values were estimated by nonstationary photo-pyroelectric thermophysical characterization using the heat pulse and thermowave modulation methods. Comparison with other carbon (C-) based thermal management materials shows that TEG-CNT-cs exhibit thermal diffusivity, effusivity, and conductivity comparable with those of actual C–polymer- and C–C-composites. For TEG-CNT-cs, evaluated values of phonon mean free path (MFP) and relaxation time (RT) are in the ranges estimated for defective graphene. The values of diffusivity and effusivity, MFP, and RT are lower for denser TEG-CNT-cs obtained by ECAO and are higher for less dense TEG-CNT-cs obtained by CO. The obtained diffusivity and effusivity values designate TEG-CNT-cs as suitable thermal management materials.

We investigated influence of multiwalled carbon nanotubes (CNTs) on spectral characteristics of composites “thermo-expanded graphite – carbon nanotubes (TEG–CNTs)”. The introduction of CNTs in an amount of 0-3% by weight of TEG composites results in a significant increase in the strength characteristics and thermal stability of the composites. This result indicates that CNTs is ideal filler for composites based on TEG compositions and structures. Measurements the giant two-polar oscillations with very small half-width 0.5 cm–1 testify the strong interaction of surface polaritons with photons. When frequencies of local oscillations of surface bonds of carbon nanotubes and modes along “nanotube-TEG” boundaries matches, then the light absorption increases 102–105 times. Thus, IR absorption with two-polar oscillations was measured at 0% of nanotubes in TEG at frequency of 2750 cm–1. It is own optical mode in the thermally expanded graphite. 5 peaks with two-polar oscillations were measured in the IR absorption spectra at 1% of carbon nanotubes. And 8 peaks with two-polar oscillations were measured at 3 % of carbon nanotubes at optical mode frequencies along the boundaries of thermally expanded graphite - carbon nanotubes. When frequencies of local oscillations of carbon nanotubes and composite’s modes matches, then the light absorption extremely increases (in 102–105 times), and two-polar IR absorption oscillations with negative components are formed. In general, two-photon interference is a result of quantum entanglement of dipole-active oscillations and splitting of photons according to the Hong-Ou-Mendel (HOM) quantum effect. Two-photon entanglement is built on the basis of the most entanglement states, also known as Bell's states. The HOM–quantum effect on composites “expanded graphite-carbon nanotubes” is promising for the development of highly coherent optical quantum computers.

The interaction of graphene with fragments of polychlorotrifluoroethylene (PCTFE) has been studied by quantum chemistry methods. Within the frameworks of the density functional theory with B3LYP exchange-correlation functional, 6-31G(d,p) basis set and the Grimme dispersion correction, and the second order Møller-Plesset perturbation theory (MP2), the values of the interaction energy of graphene with polychlorotrifluoroethylene oligomers were calculated and the most probable structures of their intermolecular complexes were optimized. As a graphene model, graphene-like planes (GLP) of different sizes were chosen, namely: С40Н16, С54Н18 and С96Н24. Oligomers of polychlorotrifluoroethylene and graphene-like planes in the formed nanocomposites are located closer to each other than individual polymer links. When comparing the results of calculations by the B3LYP-D3/6-31G(d,p) and MP2/6-31G(d,p) methods, both in the case of interactions of polychlorotrifluoroethylene oligomers with each other and intermolecular complexes of polychlorotrifluoroethylene oligomers and graphene-like planes, it has been found that the second order Møller-Plesset method is characterized by a larger intermolecular distance and a lower energy of intermolecular interactions compared to the method of the density functional theory with the Grimme dispersion correction, which is explained by the fact that the MP2 method does not fully take into account the relatively small components of dispersion interactions. Analysis of the calculation results using quantum chemistry methods shows that the addition of graphene-like planes to the polychlorotrifluoroethylene polymer leads to an increase in the intermolecular interaction energy, regardless of the calculation method used and the sizes of polychlorotrifluoroethylene oligomers and graphene-like planes. This may indicate greater strength and thermal stability of the nanocomposite based on graphene-like planes with polychlorotrifluoroethylene oligomers. The zero value of the Gibbs free energy ΔGreact for the interaction of two dimers with each other is characteristic at 270 K, and the similar value of the interaction of the PCTFE dimer with GLP is at a much higher temperature (420 K). This fact reflects the growth in thermostability of nanocomposites as compared to the polymer itself.

One of the decisive factors that determines the effectiveness of using carbon nanotubes (CNTs) for reinforcing polymer matrices is their uniform distribution in the matrix. It is shown that the percolation threshold in the polychlorotrifluoroethylene (PCTFE)–CNTs system, determined by electrical conductivity data, shifts to lower values with a more uniform distribution of CNTs, while the electrical conductivity increases and correlates with the structure and strength characteristics. Preliminary deagglomeration of CNTs was carried out using ultrasonic treatment in a dispersion of graphene nanoplatelets (GNPs). Three water systems with a CNTs content of 0.5, 0.25, and 0.125 wt.

Various 2D carbons demonstrate significant effects of surface oxidation, heating, suspending–drying, cryogelation, swelling, and adsorption of polar and nonpolar compounds on the morphological, structural, and textural characteristics. Heating at 120–150 °C could result in collapse of pores not only between carbon sheets in stacks but also between neighboring stacks; therefore, the specific surface area (SSA) decreases by a factor of 30–100 for preheated graphene oxides (GO). According to the TEM and XRD data, the GO structure is rather amorphous, since only small X-ray coherent scattering regions demonstrate a certain order giving broad XRD (001) and (002) lines. In the Raman spectra, the D line (disordered defect structures with sp3 hybridized C atoms) intensity for GO is similar to that of the G line (ordered structures with sp2 hybridized C atoms). The graphite oxide (GtO) structure, which is closer to that of graphite than that of GO, is characterized by intensive G and low D lines, and the main XRD peak at 26.4° (characteristic for graphite) is broadened similar to the XRD peak of GO at 10°. Despite the GO stacks have a tendency to collapse upon heating, the collapsed stacks can be swollen not only in water (strongly) but also in liquid nitrogen (relatively weakly). Therefore, the use of GO in aqueous media can provide great SSA values in contact with the solvent and solute molecules. This could provide high efficiency of the GO use for purification of wastewater, separation of solutes, etc. MLGO produced from natural flake graphite as a precursor (flakes < 0.2 mm in size) using a modified method of ionic hydration and freeze–drying is characterized by typical light brown color, low bulk density, flexible sheet stacks easily collapsed, but its interaction with water results in strong swelling. Interaction between the carbon sheets in preheated MLGO is strong and nonpolar molecules, such as benzene, n–decane, poorly penetrate between the sheets, i.e., intercalation adsorption is small. However, water molecules can effectively penetrate (this is rather intercalation adsorption resulting in swelling) between the sheets, but the swelling effect of water adsorbed from the gas phase could be weaker than that in the aqueous suspensions. Thus, the proposed synthesis method of MLGO using natural graphite is effective and appropriate for preparation of the materials for various practical applications.

Using the methods of quantum chemistry, the energy effects of the interaction of partially oxidized graphene-like planes with each other and the effect on this characteristic of the nature of the functional groups present in the oxidized graphene-like planes, as well as the dimensions of the graphene-like planes themselves, were clarified. It was established that the reaction between the hydroxyl and aldehyde groups of two interacting graphene-like planes is the most thermodynamically probable, regardless of the dimensions of the graphene-like planes. The reaction between two carboxyl groups of different graphene-like planes is the least thermodynamically probable. To create nanocomposites by interacting graphene-like planes with each other, it is necessary that the graphene-like planes contain hydroxyl and aldehyde groups.

The current state of the problems of protecting the surrounding environment from the impact of anthropogenic human activity because of oil extraction and using oil products is analyzed. The existing methods of liquidation of technological and emergency spills of oil products were considered. It was found that the final stage of their collection requires the use of sorbents. We compared sorption characteristics, cost, environmental friendliness of disposal, availability, etc. of existing natural, artificial, organic and inorganic sorbents. And expanded graphite (EG) was singled out as the most attractive in terms of all the considered characteristics. The sorption properties of EG were studied using the example of the absorption of heavy types of oil, petroleum and decane. The advantages of EG as a sorbent have been established. The issue of increasing the bulk mass of EG for its efficient transportation by air transport to the zone of ecological disaster elimination has been resolved.

It is known that the addition of a small amount of carbon nanomaterials significantly improves the mechanical properties of composites with a metal matrix. One of the most important, promising and available metals as a matrix for such modification is aluminum. However, at the interface between the carbon material and Al, aluminum carbides of different composition are formed, which are brittle and have the main disadvantage - solubility in water. Therefore, the appearance of aluminum carbide is a serious problem, since it contributes to the formation of defects, which, when the composite is deformed, leads to cracking of the composite due to the presence of microneedles. In this regard, in order to predict the features of the interaction of aluminum itself with the surface of carbon nanomaterials, it is advisable to model such processes using quantum chemistry methods. The aim of the work was to reveal the effect of temperature on the chemical interaction of aluminum clusters with native, boron-, silicon-, and nitrogen-containing graphene-like planes (GLP). All the calculated by three methods (B3LYP/6-31G(d,p), MP2/6-31G(d,p) and PВЕ0/6-31G(d,p)) values of the dependence of the Gibbs free energy on temperature for different cluster sizes of aluminum and graphene-like clusters are the highest for native graphene-like planes. In all cases, the values of the Gibbs free energy increase with temperature. The lowest values of the temperature dependence of the Gibbs free energy vary as dependent on the size of the reactant models and research methods, this is especially characteristic of the presence of boron and silicon atoms in the graphene-like clusters. Therefore, the absence of heteroatoms in the composition of the nanocarbon matrix contributes to the fact that aluminum carbide islands should not be formed in the carbon-containing nanocomposite with aluminum, which negatively affects the physical and chemical characteristics of the resulting nanocomposite.

The aim of the current study was to find changes in the structure and state of the surface of graphene oxide (GO) under the conditions of its reduction and modification by hetero atoms of nitrogen and amino acids. Reduction of GO was performed with hydrazine hydrate (R-GO), doping with nitrogen atoms - urea impregnation and subsequent heat treatment (N-GO), and the surface of GO was modified with sulfur-containing amino acid – L-cysteine by nucleophilic addition (L-GO). The samples obtained were characterized by analytical methods, such as Raman scattering, IR spectroscopy, TPD-mass-spectrometry, dynamic light scattering spectroscopy. The available Raman spectra indicate a defective structure of GO, reduction of GO leads to greater ordering of the structure in relation to GO, nitrating and modification by amino acid - to the opposite effect, a slight deterioration of the structural state. According to the results of IR spectroscopy, also confirmed by TPD-MS, GO has a large number of functional surface groups: (OH), (C=O), (C=C), (C-O-C), (CO-O-CO), (CH). Hydrazine reduction completely hydrophobizes the surface, in the IR spectra there is only a peak at ~ 1040 cm–1, which corresponds to CO-O-CO vibrations, with significantly reduced intensity, as well as bands at 2120 and 2300 cm–1, which indicate the aromatic nature of the samples and exist in all GO derivatives. In nitrogen and sulfur-containing samples (L-GO) a new peak of ~ 1520 cm–1appears, which corresponds to N-H vibrations in amines. Sulfur-containing derivatives have valence vibrations at 600 cm–1, which most likely corresponds to S-H bonds. Thus, modification of GO leads to a significant change in its structure and surface chemistry, which in turn affects the capability of the obtained samples to capture free radicals. Previous empirical studies have shown that this property increases in the series L-GO > GO > N-GO > R-GO.

The possibilities to enhance the properties of nanostructured surfaces are evaluated on “polymer-multiwall carbon nanotube” composites. Influence of sp3 hybridization bonds is investigated in composites derived from polypropylene, polyamide-6, polyamide-12 and polyvinyl chloride after adding CNTs to polymers. IR absorption of “polymer-CNTs” films exceeds that of polymer by 10-103 times in the entire measured spectral range. In addition, two-polar IR absorption are measured on composites with negative components at spectral positions of “D-band” and “2D-band” of sp3 hybridization. In this case, the greater oscillation amplitudes of C-C, CH2 and CH3 bonds correspond to a higher absorption at the vibration frequencies γω(CН) and γω(CH2). Two-polar oscillations of absorption with a negative component in the spectral band ranges “D” and “2D” of sp3 hybridization in nanotubes have been measured for the composites. Frequencies of 2D-band correspond to the second order frequencies of D-band. The intensity of 2D band increases with an increase in the concentration of defects. The absorption of light increases when the frequencies of local oscillations of surface bonds in carbon nanotubes correspond to the frequencies of slotted modes along the boundary of the “nanotube polymer” (surface polaritons). Two-polar oscillations have an ultra-small half width 0.4–0.6 cm–1, which indicates a strong interaction of surface polaritons with photons. Vertically polarized light along carbon nanotubes and horizontally polarized light of D and 2D bands resulted in light beams splitting, two-photon interference and realization of the quantum Hong-Ou-Mandel effect.

Experimentally, by methods of X-ray phase analysis, temperature-programmable desorption mass spectrometry, electrical resistance, tension and compression, it was found that nanoscale fillers (carbon nanotubes, pyrogenic oxides of silicon, titanium and titanium-silicon, and polymers with structure, mechanical (stress and strain deformation) and thermodynamic (melting and thermodestruction temperatures) properties. According to the results of quantum chemical calculations, such effects can be explained by the interaction of the polymer with the nanofiller and the formation of intermolecular complexes due to intermolecular dispersion forces. Експериментально, методами рентгенофазового аналізу, температурно-програмованої десорбційної мас-спектрометрії, електроопору, розтягу та стискання, встановлено, що нанорозмірні наповнювачі (вуглецеві нанотрубки, пірогенні оксиди кремнію, титану та титанокремнезему) при взаємодії з деякими біо-, сітчастими та лінійними полімерами змінюють їхню структуру, механічні (напругу та деформацію руйнування) і термодинамічні (температури плавлення та термодеструкції) властивості. За результатами квантово-хімічних розрахунків такі ефекти можуть бути пояснені взаємодією полімеру з нанонаповнювачем і утворенням міжмолекулярних комплексів за рахунок міжмолекулярних дисперсійних сил.

Metal composites modified with various heteroatoms, such as N, B, Si, are used to obtain matrix composites with specified parameters with the strongest adhesive-cohesive bonds between metal atoms and a carbon nanoparticle. Such carbon nanoparticles functionalized with heteroatoms are promising for many metal composites. One of the interesting and promising metals as a matrix for such research work is iron. To predict the specifics of the interaction of iron with the surface of carbon nanomaterials supplemented with heteroatoms of different chemical structure, it is advisable to model such processes using quantum chemistry methods. The aim of the work was to find out the effect of temperature on the chemical interaction of iron clusters with native, boron-, silicon-, and nitrogen-containing graphene-like planes (GLP). The results of the calculations show that the highest value of the energy effect of the chemical interaction for the native graphene-like plane is +204.3 kJ/mol, in the case of calculations both by the B3LYP/6-31G(d,p) method and by the MP2/6-31G(d, p) (+370.7 kJ/mol). The lower value of the energy effect is found in the presence of nitrogen atoms in the composition of the graphene-like plane. This value is even lower for the interaction of iron dimers with a silicon-containing carbon nanocluster. The lowest values of the energy effect, calculated by both methods, are characteristic of the boron-containing graphene-like plane. In particular, for the B3LYP/6-31G(d,p) method, the value of the energy effect of the reaction is ‑210.5 kJ/mol, and for the MP2/6-31G(d,p) method this value is +16.6 kJ/mol. The presence of boron atoms in the composition of the nanocarbon matrix best contributes to the interaction with the iron nanocluster, regardless of the chosen research method. The dependence curves of the Gibbs free energy of the interaction of iron dimers with a graphene-like plane and its derivatives in all cases qualitatively correlate with similar energy effects. In addition, in all cases, the values of the Gibbs free energy increase with increasing temperature.

Nitrogen-containing carbon nanotubes (CNTs) were synthesized by the CVD method on oxide catalysts of Al-Fe-Mo-O by adding acetonitrile or ethylenediamine to the carbon source (propylene), or completely replacing it, as well as impregnating the original CNTs with urea, followed by heat treatment. The structure of nitrogen-containing CNTs (N-CNT) was characterized by the method of Raman scattering, transmission electron microscopy (TEM), differential thermal and gravimetric analysis (DTA, DTG) and X-ray photoelectron spectroscopy (XPS). The influence of the synthesis method on the number and chemical state of nitrogen heteroatoms in the structure of the carbon matrix is found. According to the TEM, nitrogen-containing CNTs have a characteristic bamboo-like structure, which is less perfect compared to the structure of the original CNTs: the characteristic Raman bands (G and D) are shifted to higher frequencies, their half-width and band D intensity increase relative to G. This is also manifested in the lower thermal stability of nitrogen-containing CNTs. According to the XPS, the direct synthesis of nitrogen-containing CNTs increases the total content of nitrogen atoms and the proportion of pyrrolic and quaternary nitrogen against the background of a significant decrease in the amount of pyridinic form. This can be explained by the fact that nitrogen is evenly distributed throughout the carbon matrix of CNTs, and during nitriding of CNTs with urea, nitrogen is included mainly in the surface layers and defects, because the pyridine form is characteristic of the edge location of the nitrogen atom in the graphene plane.The catalytic effect of multilayer nitrogen-containing carbon nanotubes (N-CNT) on the kinetics of decomposition of hydrogen peroxide in aqueous solutions at different pH values is considered. It is concluded that the method of direct synthesis of nitrogen-containing CNTs allows to obtain more catalytically active carbon nanotubes containing more nitrogen, mainly pyrrolic and quaternary type. It has been found that regardless of the method of synthesis, the maximum catalytic activity in the decomposition of hydrogen peroxide is observed at pH 7.

The description of the method developed by the authors of modification of the carbon black (CB) reinforced rubber composition by addition multiwall carbon nanotubes (CNTs) into its composition is presented. The process includes the pre-formation of a mixture of CB with CNT by their joint treatment in a liquid, which ensures deagglomeration of CNTs and uniform distribution of CNTs and CB among themselves, subsequent drying, loosening and addition into the rubber composition with stirring. The amount and composition of hybrid nanofiller (CB and CNTs), as well as the method of CNTs inclusion: CB addition, CB substitution or its partial substitution is determined by a calculation that takes into account the ratio between the specific surface of CB and CNTs and the average particle size. Comparison of the predicted values of CNTs and CB with experimental data for rubber compositions with optimal characteristics based on both natural and synthetic rubbers shows the high efficiency of the applied method.