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The possibility of stabilizing aqueous dispersions of carbon nanotubes (CNTs) using phenol-formaldehyde resin (PFR) and aminocumulene (AC) is shown. The preliminary oxidation of CNTs contributes to their higher solubility in the presence of these stabilizing agents. The concentration of pristine and oxidized CNTs in weakly alkaline solutions containing 2.5 g/L of PFR is 3.0 and 11.4 g/L, respectively. AC promotes the formation of stable dispersions in acidic media with the concentrations of pristine and oxidized CNTs, respectively, 3.3 and 20.4 g/L. A decrease in the effective sizes of agglomerates of both pristine and oxidized CNTs in the presence of PFR and AC has been shown by dynamic light scattering method. According to TG/DSC analysis and Raman spectroscopy data, it was concluded that the oxygen-containing groups of oxidized CNTs interact with the surfactants used. Schemes for the formation of hydrogen and chemical bonds between CNTs and PFR or AС were proposed, which made it possible to explain the effect of dispersion. [ABSTRACT FROM AUTHOR]

In the present paper, the features of obtaining a metal oxide Fe–Co/Al2O3 catalyst for the synthesis of carbon nanostructured materials through thermal decomposition are considered. It was experimentally proved that the temperature and duration of the stage of thermal decomposition of the initial components solution significantly affect the catalyst activity in the synthesis of carbon nanostructured materials by the CVD method. It was found that controlling the mode parameters of the thermal decomposition of the initial components solution of the Fe–Co/Al2O3 catalyst, one can not only obtain a catalyst with the required characteristics but also directionally synthesize carbon nanostructured materials over the resulting catalytic systems. During the experiments, rational modes for the implementation of the method for producing catalysts were determined, allowing to form a metal oxide system with a specific surface area of 108 m2/g, the use of which in the synthesis of carbon nanostructured materials leads to the formation of multi-walled carbon nanotubes with an external diameter of 30 nm. [ABSTRACT FROM AUTHOR]

Abstract In spite of good development and progress in lubricants, billions US dollars are being lost in many industries and motor vehicles globally due to engine frictions. Therefore, there is a great need to develop more efficient and effective lubricants. Many people modified lubricants by using nano materials, which seems to be a bright future. The present review paper considers the application of carbon nanostructures, such as carbon nanotubes and graphene, as nano-additives to lubricants in order to improve their tribological characteristics i.e. to decrease friction and wear. Some important aspects of nanoparticles in modifying lubricants are size, form, structure, surface functionalization, concentration, physical and chemical properties of surfaces, which are outlined in this article. It was observed that the adding of nano-additives to lubricants; even at low concentrations; considerably decreased the friction and wear coefficients. Moreover, carbon nanotubes and graphene are environmentally friendly and safe. Thus, all these factors allow positive assessment of the prospects of using the abovementioned nanomaterials to modify lubricants. The present article will be useful for the researchers and industrial persons. Highlights • Different carbon nanomaterials are lubricant modifiers. • Improves tribological properties of the lubricants due to carbon nanoparticles • Graphene nanoparticles: Most prospective lubricants additives • Carbon nanotubes and graphene are environmentally friendly and safe lubricant modifiers. [ABSTRACT FROM AUTHOR]