Solvent-based methods for production of graphene nanoribbons

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry and nanotechnology. Plurality of carbon nanotubes is exposed to a source of alkali metal in presence of an aprotic solvent and in absence of protic solvent. Carbon nanotubes opened in a direction parallel to their longitudinal axes are obtained. To obtain non-functionalised graphene nanoribbons, opened carbon nanotubes are exposed to a protic solvent. To obtain functionalised graphene nanoribbons, opened carbon nanotubes are exposed to an electrophile. Obtained graphene nanoribbons have specific conductivity of 0.1–9,000 S/cm.

EFFECT: invention can be used for production of composites and fibres for displays, deicing circuits, gas-permeable composites and screens.

52 cl, 36 dwg, 6 ex, 1 tbl

 



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to chemical fibre technology and a method of spinning fibres from graphene ribbons. The method of spinning fibres from graphene ribbons begins with unfolding carbon nanotubes to form graphene ribbons, cleaning and drying the graphene ribbons and dissolving the graphene ribbons in a suitable solvent, preferably a superacid, to form a spinning solution. The spinning solution is used to spin such that spliced fibres are fed into a coagulation medium, also known as an anti-solvent, where spun or spliced fibres undergo coagulation. The coagulation medium flows in the same direction as the orientation of fibres formed from the graphene ribbons. The coagulated fibres, formed from the graphene ribbons, are pulled off, neutralised and washed and then wound on a spool.

EFFECT: invention enables to produce fibres from graphene ribbons.

15 cl, 7 dwg

FIELD: nanotechnology.

SUBSTANCE: group of inventions relates to the field of nanotechnologies, in particular to the technologies of production of carbon nanostructures and nanomaterials for use as substrates for applied catalysts, high-strength fillers, and relates to hollow carbon nanoparticles, carbon nanomaterial and method of its preparation. The carbon nanoparticle has an average size of not less than 5 nm, and comprises a central inner cavity and an outer closed casing enclosing the inner cavity on all sides. At that the outer casing comprises at least a pair of separate carbon layers. The carbon material comprises a mixture of hollow carbon nanoparticles comprising a central inner cavity and an outer closed casing enclosing the inner cavity on all sides. At that the outer casing comprises at least a pair of separate carbon layers, and the single-walled and double-walled carbon nanotubes. The method of producing the carbon material comprising a mixture of hollow carbon nanoparticles and single-walled and double-walled carbon nanotubes comprises catalytic decomposition of hydrocarbons at a temperature of 600-1200°C with obtaining a mixture of carbon nanoparticles, which is separated from the gaseous products and annealed at 1700-2400°C in the atmosphere of inert gas.

EFFECT: invention provides obtaining of novel carbon nanoparticles and nanomaterials having high strength at low weight, which can be used to create new composite light and high strength materials.

4 cl, 2 dwg, 3 ex

FIELD: nanotechnology.

SUBSTANCE: invention relates to a method of production of carbon nanofibres and/or carbon nanotubes. The method comprises the pyrolysis of dispersed cellulosic and/or carbohydrate substrate impregnated with a compound of the element or elements, which metal or alloy, respectively, is able to form carbides in the substantially oxygen-free atmosphere comprising a volatile silicon compound, optionally in the presence of carbon compound.

EFFECT: invention enables to obtain carbon nanotubes or nanofibres of a certain shape.

15 cl, 4 dwg

FIELD: chemistry.

SUBSTANCE: apparatus for thermal treatment of carbon-containing fibrous materials includes a carbonisation device and a graphitation device insulated from the carbonisation device, between which is integrated a device for accumulating and cooling carbonised material and/or washing and drying thereof. The graphitation device can be in the form of two identical electro-graphite furnaces which are not linked with each other and arranged in parallel one over the other. The electro-graphite furnace includes a heating element, a pipe for removing volatile products, a valve at the outlet for preventing entry of gaseous medium into the furnace, pipes for feeding an inert gas, a drive mechanism for transporting the material to be thermally treated, and a cooled metal housing with a heat insulation unit, in which there are horizontal slit-type channels for transporting material. The inlet channel is in the form of a pipe with a rectangular cross-section for removing volatile products, and between its upper and lower inner surfaces over the transported material at an inclination to said surfaces there is a graphite screen with gaps between the upper surface of the channel and the upper end of the screen, and between the lower surface of the channel and the lower end of the screen. The screen divides the heating chamber into a maximum temperature area, having a heater, and a medium temperature area.

EFFECT: high efficiency and stability of the process of thermal treatment of carbon-containing fibrous materials, high quality of the end product.

4 cl, 5 dwg

FIELD: electricity.

SUBSTANCE: nanoobjects sorting method (objects with at least one spatial dimension within the range from ~0.05 nm up to ~500 nm) wherein a) the initial mix with any primary content of electrically conductive nanoobjects and more electrically conductive nanoobjects contact any part of liquid substance surface; b) energy of the above mix of nanoobjects is transmitted so that different nanoobjects depending on degree of their conductivity are subjected to different degree of heating (per time unit), at that during any non-zero period of time upon beginning of the energy transmission T temperature is maintained in any part of the above contact substance surface at the level sufficient for compliance with at least one of the following conditions: (1) temperature T differential module for any part of the above surface of the contact substance and temperature of its active evaporation (Te) is less than ΔTn (i.e. |Te-T|<ΔTn), (2) temperature T differential module for any part of the above surface of the contact substance and temperature of the active chemical reaction threshold with the above substance (Tcs) is less than ΔTn (i.e. |Tcs-T|<ΔTn), (3) temperature T differential module for any part of the above surface of the contact substance and temperature of the active chemical reaction threshold with nanoobjects (Tcn) is less than ΔTn (i.e. |Tcn-T|<ΔTn)), and moreover it is provided that nanoobjects heated up to different temperature (Tn) are subjected to different degree of fixation with the contact surface (up to failure to fix), c) non-fixed and weakly fixed nanoobjects are separated from the surface and d) at least one spatially separated object is received out of pluralities of nanoobjects, which contains nanoobjects with the average conductivity differing from the average conductivity of nanoobjects in the initial mix.

EFFECT: improving the efficiency of sorting.

7 cl, 1 dwg, 12 ex

FIELD: chemistry.

SUBSTANCE: invention relates to chemical technology, in particular to processes of carbonisation of fibrous viscose materials, and can be used in production of graphitised fibrous materials, used as filling agents of composite materials; electrodes; flexible electric heaters; filters of aggressive media; in products for sport and medical purposes, etc. The material is preliminarily subjected to relaxation processing. The obtained material, which contains a pyrolysis catalyst, is continuously transported through zones of carbonisation heating. Carbonisation is carried out to 320-360°C in not less than three zones of heating, heat- and gas-isolated one from another by transporting material with inclination from bottom to top, with increase of heating temperature from 160-200°C in the first zone by 40-60°C in each next zone of heating, in comparison with the previous one. Volatile products are simultaneously removed from the said zones into the evacuation zone, heat- and gas-isolated from the external environment and located above the heating zones and connected with them via a perforated wall. Temperature in the evacuation zone of volatile substances is set by 5-15°C higher than temperatures of the respective heating zones, temperature of the output branch piece being 5-15°C above the maximum temperature of carbonisation.

EFFECT: invention ensures increase of the process efficiency and improvement of quality of the obtained carbon fibrous materials.

2 dwg, 1 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: method involves treating viscose fibre material with pyrolysis catalysts, heating to carbonisation temperature and subsequent graphitation to temperature of 3000°C in an inert medium. Carbonisation is preceded by preparation of precursor by preliminary washing of the starting material with water and/or 5-10% sodium hyposulphite solution with heating and drying, and/or ionising irradiation with a beam of fast electrons during transportation through the irradiation chamber of an electron accelerator, and/or warm-wet synthesis of a complex catalyst on the surface of viscose fibres and in the pore system thereof in boiling 10-20% aqueous ammonium chloride solution and with addition of diammonium phosphate in ratio of 0.5-4.0, followed by steaming in hot steam and final ventilated drying with constant transportation, which enables to deposit the catalyst in form of an amorphous film.

EFFECT: high stability of the process of carbonising viscose fibre material and improved physical and mechanical properties of the obtained carbon material.

6 cl, 7 dwg, 1 tbl, 12 ex

FIELD: chemistry.

SUBSTANCE: invention relates to modification of the surface of inorganic fibre by forming a highly developed surface of inorganic fibre used as filler by forming carbon nanostructures on the surface of the fibres and can be used in producing high-strength and wear-resistant fibre composite materials. The method of modifying the surface of inorganic fibre involves the following steps: (a) soaking inorganic fibre with a solution of an α2 sinter fraction in organic solvents; (b) drying the soaked fibre; (c) heat treatment of the soaked inorganic fibre at 300-600°C; (d) depositing a transition metal salt onto the surface of the fibre heat treated according to step (c); (e) reducing the transition metal salt to obtain transition metal nanoparticles; (f) depositing carbon onto the transition metal nanoparticles to obtain carbon nanostructures on the surface of the fibre. The composite material contains modified fibre made using the method given above and a matrix of polymer or carbon.

EFFECT: high strength of the composite material in the cross direction relative the reinforcement plane by preventing surface deterioration when modifying with carbon nanostructures.

9 cl, 3 ex, 1 tbl, 5 dwg

FIELD: process engineering.

SUBSTANCE: proposed method comprises processing initial cellulose fibrous material by liquid-phase composition containing silanol groups with molecular weight varying from 900 to 2400 and viscosity varying from 520 to 1700 cPs, and 2-7%-water solution of fire retardant. Processed material is dried to 105-125°C for 60-120 min. Then, carbonisation is performed in air at 140-170°C for 25-40 min. Carbonisation is terminated at 700°C to proceed with high-temperature processing at, at least, 2200°C.

EFFECT: high physical properties and yield.

4 cl, 6 ex

FIELD: chemistry.

SUBSTANCE: invention relates to heterogeneous catalysis and can be used to recycle hydrocarbons and halogen-substituted hydrocarbons when producing composite materials, catalysts, sorbents and filters. Catalytic pyrolysis of hydrocarbons is carried out at 500-700°C on a catalyst obtained by dispersing articles of solid nickel and alloys thereof with other metals, e.g., iron, chromium, as a result of reaction with 1,2-dichloroethane vapour. The catalyst contains dispersed active nickel particles attached to carbon nanofibres with diameter 0.1-0.4 mcm. The starting material used is bromine- or chlorine-containing hydrocarbons, alkanes, olefins, alkynes or aromatic hydrocarbons, e.g., ethane, propane, acetylene, benzene. Output of carbon nanofibres is equal to or more than 600 g per 1 g metal.

EFFECT: high efficiency of the method.

5 cl, 2 dwg, 9 ex

FIELD: chemistry.

SUBSTANCE: invention relates to field of nanotechnologies and can be used for obtaining composite materials with high electric and heat conductivity, additives to concretes and ceramics, sorbents, catalysts. Carbon-containing material is evaporated in volume thermal plasma and condensed on target surface 9 and internal surface of collector 7. Plasma generator 3, which includes coaxially located electrodes: rod cathode 4 and nozzle-shaped output anode 5, are used. Gaseous carbon-containing material 6 is supplied with plasma-forming gas through vortex chamber with channels 2 and selected from the group, consisting of methane, propane, and butane. Bottom of collector is made with hole 8 for gas flow to pass.

EFFECT: invention makes it possible to reduce energy consumption of the process, extend types of applied hydrocarbon raw material, simplify device construction and provide continuity of the process and its high productivity.

2 dwg, 3 ex

FIELD: nanotechnologies.

SUBSTANCE: inventions relate to nanotechnology and may be used to manufacture catalysts and sorbents. Graphene pumice contains graphenes arranged in parallel at distances of more than 0.335 nm, and amorphous carbon as a binder at their edges, with the graphene-binder ratio from 1:0.1 to 1:1 by mass. The specific area of the surface is more than 1000 m2/g. The absolute hardness is 1 unit by the Mohs scale and less, specific density is 0.008-0.3 g/cm3 for solids, loose specific density of 0.005-0.25 g/cm3 for granules. The composition is produced by burning of a homogeneous powder mix of graphite oxide, unstable organic material and organic and inorganic metal salts with the moisture of all components of 10-15% in a heat-resistant open or tight mould. The source material for the binder is represented by chemical compounds capable of being in a liquid state up to 180°C, not soaking the graphite/graphene surface and damaged at a temperature of not more than 800°C. Graphene pumice is activated by restoration in hydrogen at 400-450°C and pressure of 0.05-0.11 MPa for 10-30 min or in methane at 800-950°C for at least 1 hour at atmospheric pressure with subsequent cooling.

EFFECT: produced sorbents make it possible to multiply increase the capacity of reservoirs for the storage and transportation of natural gas.

15 cl, 8 dwg, 2 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: graphite-containing component is mixed with a kaolin-based filling agent, dry mixing with simultaneous dispersion successively in a drum and centrifugal mixers is carried out. After that, a magnetised water solution of an alumoborophosphate concentrate, containing a surface-active substance, is introduced, and a wet batch in a screw mixer is carried out. After that, the obtained mass is processed in a tribochemical disperser under conditions of vacuuming and all-around compression to a pressure of 5-20 MPa. The tribochemical disperser includes a hermetic hollow cylindrical case 40, which has flanges 41 and 42 on butt ends, a permeable piston 44 with a rod 45, a drive 46 of reciprocating movement, means for the cavity vacuuming 43, two vacuum gate valves 471 and 472. The piston 44 represents a packet of adjoining each other pairs of metal nets which have the different cell size, located between two protective grids 445. The products are moulded from processed mass with their further thermal processing.

EFFECT: reproducibility of specific electric resistance in the products is provided, with the nanocomposite mass acquiring isotropic properties and ductility.

20 cl, 4 dwg, 2 ex

FIELD: chemistry.

SUBSTANCE: first, particles of thermally expanded graphite are obtained by heating particles of hydrolysed graphite nitrate with specific melt energy equal or higher than 4.7 kJ/g in the atmosphere of products of combustion of liquid or gaseous fuel in air with the coefficient of air excess counted per fuel λ=0.8-1.1. Obtained thermally expanded graphite is compacted to the seeming density from 0.03 to 0.1 g/cm3 by rolling or uniaxial pressing. After that, the material is cut into measured blanks. At least, two measured blanks are subjected to joint compression with obtaining a monolith material. The finished low-density material is made in the form of long-measuring product up to 1500 mm wide.

EFFECT: invention makes it possible to obtain the low-density heat-conducting material, possessing high bending strength and elasticity modulus and characterised by the absence of acidic corrosion-active additives.

10 cl, 3 ex

FIELD: chemistry.

SUBSTANCE: apparatus for producing thermally expanded graphite includes a feeding device 1, a circular waveguide 6, a storage hopper 19, a device for feeding blow-down carbon dioxide gas or air, magnetron generators, a belt conveyor with lower 2 and upper 3 belts formers 4 and 5. The circular waveguide 6 is provided with gas valves 15, longitudinal slits 14, communication windows 11 with insulating quartz inserts 12, insulating quartz rings 7 and 16 and is divided into sections having horn radiators 9 and 10. A layer of oxidised graphite undergoes microwave treatment for 0.1-0.5 s with power which provides temperature of 1500-1800°C, which is then lowered to provide temperature of 500-1000°C for 3-10 s.

EFFECT: high chemical purity and specific surface area and low packed density of thermally expanded graphite.

4 cl, 1 dwg

FIELD: nanotechnology.

SUBSTANCE: invention relates to nanotechnology and is intended for use in creation of modern thin-film semiconductor devices and structures of nanoelectronics. In the method of production of fluorographene layer the layer of desired thickness is separated from the volume graphite and is placed on the substrate. Then a fluorination operation is carried out using hydrofluoric acid under conditions enabling to obtain fluorographene layers with thickness up to 10-15 nm. At that the silicon substrate is used. On its working surface a silicon oxide layer can previously be grown. Fluorination is carried out in the aqueous solution of hydrofluoric acid with the content of 3-7% HF with the treatment duration up to 30 minutes, but not less than tcr, where the conductivity of fluorinated layers is changed. At that, when fluorination the temperatures up to 60°C are used.

EFFECT: improvement of quality of fluorographene layers is achieved, reduction of defectiveness, reduction of duration of the process, increase in ecological compatibility.

6 cl, 2 dwg

FIELD: electricity.

SUBSTANCE: invention is referred to electronic graphene device. Flexible and stretchable translucent electronic device contains the first graphene electrode, the second graphene electrode, graphene semiconductor and control graphene electrode located between the first and second graphene electrodes and being in contact with graphene semiconductor. Each of the above electrodes has porous graphene layer with a number of pores, at that each of the above electrodes has porous graphene layer and power supply source. Graphene semiconductor, the first and second graphene electrodes are configured so that current from power supply source between the first location at the first graphene electrode and the second location at the second graphene electrode sets difference of potentials between the first and second locations and this difference of potentials remains permanent when the first or second location changes.

EFFECT: improving charge-carrier mobility, ensuring ballistic transport, increasing current density and specific conductivity and possibility to control electric performance of the device.

15 cl, 3 dwg

FIELD: chemistry.

SUBSTANCE: claimed is carbon-containing material, obtained by pyrolysis of xarogel from hydrophilic polymer of polyhydroxybenzol/formaldehyde type and nitrogen-containing latex. Polymer and latex are co-crosslinked. Material represents carbon monolith, containing from 0.1 to 20% of graphite by weight of total material weight. Material contains system of pores, at least, 10% of which are mesopores, with pore volume constituting from 0.4 to 1 cm3/g. Material is characterised by presence of, at least, 3 successive characteristic peaks in the spectrum of X-ray diffraction. Claimed are: method of material obtaining and gel for its obtaining. Claimed material is used for production of electrodes and as filling agent in production of electric current-conducting components.

EFFECT: obtaining material with controlled porosity and reduction of material resistivity.

14 cl, 2 dwg, 5 tbl

FIELD: chemistry.

SUBSTANCE: invention can be used in making high-heat areas of structures subjected to aggressive oxidative media. A graphite workpiece is subjected to vacuum embedding with high-temperature coal-tar pitch at temperature higher than the melting point of the pitch. Simultaneous saturation and carbonisation is then carried out at pressure of (80-105) MPa at temperature (700-750)°C, while maintaining said pressure and temperature for at least 4 hours and high-temperature vacuum treatment is carried out while maintaining temperature of (2100-2300)°C for at least half an hour.

EFFECT: high density and strength of the obtained material while still enabling the manufacture of large components from said material.

5 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to electronics and nanotechnology and cab be used in production of composite containing laminar graphite- and molybdenum sulphide-based materials. TEG or oxidised graphite and thiomolybdate are used as initial compounds. Note here that thiomolybdate is decomposed in the mix with TEG or oxidised graphite at heating or subjected to decomposition in solution with acid medium. Formed product containing TEG or oxidised graphite and precursor of molybdenum sulphide are flushed and heated in vacuum to 350-1000°C to obtain composite including molybdenum sulphide on graphite layers pile of composition MoxSy, where x=1-3, y=2-4. Note also that TEG or oxidised graphite are pre-dispersed while molybdenum precursor represents molybdenum tri-sulphide.

EFFECT: possibility to vary size, morphology and phase composition of nanoparticles on graphite surface.

4 dwg, 5 ex

FIELD: measurement equipment.

SUBSTANCE: method for determining a range of sizes of suspended nanoparticles consists in passage of gas (mixture of gases) containing analysed particles, through diffusion batteries of a meshed type and their introduction to supersaturated vapours of a low-volatile enlarging substance. Then, lighting of a flux of particles with a light beam and recording of parameters of light signals shaped by enlarged particles at their flying through the pointed-out area of the flux is performed. In order to improve accuracy of determination of the range of sizes, the main flux is separated into six parallel fluxes. With that, five of them are passed through five diffusion batteries with a different slip, and one of them is passed directly. Then, these fluxes pass through six devices of condensation growth and then to a field of vision of a charge-coupled device matrix and the obtained six areas of images of enlarged fluxes of particles are transmitted to a computer for an analysis of their range of sizes. Unlike known ones, the method allows performing simultaneous processing by means of a computer of six images of enlarged particles, which characterise different dimensional ranges of nanoparticles.

EFFECT: reducing the time required for measurements and improving their accuracy.

1 dwg

Up!