Method of obtaining dispersions of carbon nanotubes

FIELD: chemistry.

SUBSTANCE: invention can be used in manufacturing polymer-based composites. Carbon nanotubes are functionalised by carboxyl and/or hydroxyl groups and processed by ultrasound in an organic solvent in the presence of products of reaction of tetrabutyltitanate with stearic or oleic acid at a temperature from 40oC to the temperature of the solvent boiling.

EFFECT: obtained dispersions of the carbon nanotubes are stable in non-polar organic solvents.

2 cl, 6 ex

 

The invention relates to the technology of carbon nanomaterials, particularly to methods of obtaining compositions containing carbon nanotubes dispersed in different environments.

Carbon nanotubes (CNTS) tend to form agglomerates, which complicates their implementation in different environments. Typically, to achieve a uniform distribution of carbon nanotubes in solvents and polymers used surfactants, sonication or treatment with various mechanical mills, and the original CNTS functionalitywith by chemical grafting of certain groups. There are many ways to obtain stable dispersions of carbon nanotubes in different environments. Next, we consider only those methods that are most similar to the claimed invention at essential features.

Numerous variants of the method of preparation of stable dispersions of carbon nanotubes in water and polar organic solvents, including vaccination to the surface of the CNTS polar phenolic groups, quinoid, carboxyl (in other terms, the functionalization of CNTS polar oxygen-containing groups). This is achieved by treating the CNTS of different oxidants in liquid or gas phase. As oxidizing agents are used nitric acid or its mixture with sulfuric Ki is lotay, the ammonium persulfate and hydrogen peroxide in acidic or alkaline medium, nitrogen dioxide, sodium hypochlorite, ozone, potassium permanganate and other strong oxidizing agents (V. Datsyuk, M. Kalyva, K. Papagelis, J. Parthenios, D. Tasis, Siokou A., Kallitsis L, Galiotis C. Chemical oxidation of multiwalled carbon nanotubes //Carbon, 2008, vol.46, p.833-840. Schierz, A., Zanker H. Aqueous suspensions of carbon nanotubes: Surface oxidation, colloidal stability and uranium sorption //Environmental Pollution, 2009, vol.157, p.1088-1094. Shieh Y.-T., Liu, G.-L., Wu, H.-H., Lee C.-C. Effects of polarity and pH on the solubility of acid-treated carbon nanotubes in different media //Carbon, 2007, vol.45, p.1880-1890).

Common essential characteristics considered and the inventive method is the availability of operations functionalization of CNTS polar oxygen-containing groups under the action of oxidizing agents.

The disadvantage of the considered method is that it not only provides, but even deteriorates the dispersibility of CNTS in nonpolar organic media.

So, there are various options of method of obtaining aqueous dispersions of carbon nanotubes using ionic or nonionic surfactant - surfactant (Chen, L., Xie, N., Li Y., Yu W. Applications of cationic gemini surfactant in preparing multi-walled carbon nanotube contained nanofluids //Colloids and Surfaces A: Physicochem. Eng. Aspects 330 (2008) 176-179. Rastogi R, Kaushal R, Tripathi S.K, A.L. Sharma, Kaur I., L.M. Bharadwaj Comparative study of carbon nanotube dispersion using surfactants //Journal of Colloid and Interface Science 328 (2008) 421-428. Vaisman L., H.D. Wagner, Marom G. The role of surfactants in dispersion of carbon nanotubes //Advances in Colloid and Interface Science 128-130 (2006) 37-46. The application of the U.S. 20060099135, IPC D01F 9/12, 2006). The agreement is but this way of CNTS dispersed in water, containing dissolved surface-active substance, with the help of ultrasound. As surface-active substances used sodium salts of organic sulphonic acids (for example, dodecylsulfonate sodium, dodecylbenzenesulfonate sodium and others), the cationic surfactant is a Quaternary ammonium salt containing attached to the nitrogen atom long chain organic group, nonionic surfactants, which usually contain, as hydrophilic groups are polyethylene glycol, and as a hydrophobic group - alkyl substituted benzene ring. These surfactants adsorbed on the surface of CNTS with their hydrophobic groups, while the hydrophilic groups provide good wettability. Due to this it is possible to obtain a sufficiently stable aqueous dispersions of carbon nanotubes. Usually for disaggregation of CNTS in water in the presence of surfactants used ultrasound that is most convenient. However, the same result can be achieved by using devices such homogenizer, colloid mill, etc.

Common essential characteristics considered and the proposed method is used for dispersing CNTS bifunctional substances, capable, on the one hand, to interact with the surface of the CNTS, on the other hand, it is well wettable dispersion medium.

The disadvantage of this method is in the lane who's that that surfactant capable of decorrelates from the surface of the CNTS. If the dispersion of the CNTS used for the preparation of composite materials, the presence in their composition of surfactants in some cases undesirable. Another disadvantage of the considered method is that the surfactants of the specified type provide stable dispersions of carbon nanotubes in water, but is ineffective work in polar organic solvents and inefficient to obtain dispersions of carbon nanotubes in non-polar environments.

In the work (Application USA 20080176071, IPC WV 1/20, WV 27/06, 2008) described a method of producing dispersions of carbon nanotubes in which the nanotubes was dispersed ultrasonically in water mixed with a cationic surfactant containing a vinyl group, and then add the initiator of free radicals. The result of the CNT surface, covered with a layer of chemically related molecules of the surfactant. Due to the chemical grafting of surfactant molecules to the surface of the nanotubes obtained dispersion is stable at all dilutions, since the surfactant is not desorbed from the surface of the nanotubes.

Common essential characteristics considered and the proposed method is the treatment of carbon nanotubes with molecules containing reactive group and a hydrocarbon group, in terms of reaction prishivki molecules to the surface of the nanotubes.

The disadvantage of the review is sent to the steering method is that it is not possible to obtain a stable dispersion of CNTS in nonpolar environments.

There are various options of method of preparation of stable aqueous dispersions of carbon nanotubes, in which the stabilizer is applied biological polymers or chemically synthesized polar polymers (J.U. Lee, J. Huh, K.H. Kim, S. Park, W.H. Jo Aqueous suspension of carbon nanotubes via non-covalent functionalization with oligothiophene-terminated polyethylene glycol) //Carbon 45 (2007) 1051-1057., Moulton SE, Minett, A.I., R. Murphy, K.P. Ryan, D. McCarthy, J.N. Coleman, W.J. Blau, Wallace G.G. Biomolecules as selective dispersants for carbon nanotubes //Carbon 43 (2005) 1879-1884, Li Z., Wu Z., Li K. The high dispersion of DNA-multiwalled carbon nanotubes and their properties //Analytical Biochemistry 387 (2009) 267-270, U.S. Patent 7588941, IPC C12Q 1/18, C12M 1/00, 2009, the Application of the U.S. 20090162277, IPC F61K 9/14, C12Q 1/02, AK 51/02, AK 49/00, 2009).

Common essential characteristics considered and the proposed method is used for dispersing CNTS bifunctional substances, capable, on the one hand, to interact with the surface of the CNTS, and on the other hand, it is well to soak dispersion medium.

The disadvantage of the considered method is that it is not possible to obtain a dispersion of carbon nanotubes in non-polar organic media. In addition, again, using the so prepared dispersion of carbon nanotubes for preparation of composite materials, the presence of a composite material of biological molecules in some cases is undesirable.

And is known a method of producing dispersions of carbon nanotubes in polar organic solvents with the use of polymeric surfactant - polyvinylpyrrolidone (U.S. Pat. USA 7682590, IPC D01F 9/12, WV 1/00, C08J 3/02, SC 3/04, SC 7/24, 2010). This method involves the processing of suspensions of carbon nanotubes by ultrasound in a polar organic solvent containing dissolved polyvinylpyrrolidone.

Common essential characteristics considered and the proposed method is used for dispersing CNTS bifunctional substances, capable, on the one hand, to interact with the surface of the CNTS, and on the other hand, it is well to soak dispersion medium.

The disadvantage of the considered method is that it is not possible to obtain a dispersion of carbon nanotubes in non-polar organic media. In addition, for the preparation of composite materials, the presence of a composite material polyvinylpyrrolidone in some cases is undesirable.

A method of obtaining dispersions of carbon nanotubes in non-polar organic solvents (e.g. n-heptane), which includes the sonication of a suspension of carbon nanotubes in an organic solvent containing a block copolymer of polystyrene and polyisoprene (Sluzarenko N., Heurtefeu Century, Maugey M, Zakri C, Poulin P., S. Lecommandoux Diblock copolymer stabilization of multi-wall carbon nanotubes in organic solvents and their use in composites //Carbon, 2006, vol.44, p.3207-3212). In this case, the block copolymer is adsorbed on the surface of CNTS and provides the wettability of the non-polar solvent. Another variant of this method is described in the application U.S. 20090118420, IPC C08L 25/08, B29D 7/01, 2009, where as dispersant for CNTS using soluble in organic solvents block copolymers containing blocks with associated links and blocks without conjugate relations. In the presence of these copolymers CNTS dispersed by ultrasound in various organic solvents (chloroform, toluene, tetrahydrofuran). Get a stable dispersion.

Common essential characteristics considered and the proposed method is used for dispersing CNTS bifunctional substances, capable, on the one hand, to interact with the surface of the CNTS, and on the other hand, it is well to soak dispersion medium.

The disadvantage of the considered method is that when using the thus obtained dispersions of carbon nanotubes for the preparation of polymer composites, the presence of a composite material of a foreign polymer in some cases worsen the properties of the composite material. In addition, the block copolymers of this type, as a rule, are of laboratory developments and are not produced on an industrial scale.

Closest to the claimed invention is a method of producing dispersions of nanotubes described in US patent No. 8187566, CL SW 31/04, 29.05.12, including functionalization of carbon nanotubes carboxyl and/or hydro is strong groups and subsequent processing in an organic solvent ultrasound.

Overview of organic titanium compounds containing CNS group, their reactions and methods of obtaining derivatives containing CNS group and the remains of the fatty acids described in (Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition), vol. 24, 538 p. P.141, 142 (s-142). On the basis of indirect data, it was assumed that substances of this type are oligomers containing in the polymer chain titanicmovie links, and as side groups CNS group and residues of fatty acids. As follows from the information given in the U.S. patent 2621193 and Kirk-Othmer Encyclopedia of Chemical Technology, substances of this type are good dispersing agents and surface modifiers for carbon materials in non-polar environments. Probably, these substances work as surfactants adsorbed on the surface of carbon materials and providing good wetting of the particles of carbon materials nonpolar organic solvents.

Common essential features of the prototype method and the claimed invention is the functionalization of carbon nanotubes carboxyl and/or hydroxyl groups and the subsequent processing of functionalized nanotubes in an organic solvent ultrasound.

The disadvantage of the prototype method is that it does not provide a sufficiently stable dispersion is the second carbon nanotubes in non-polar organic media.

The basis of the claimed invention is tasked by pre-functionalization of carbon nanotubes carboxyl and/or hydroxyl groups and subsequent processing of functionalized nanotubes in an organic solvent ultrasound to obtain stable dispersions of carbon nanotubes in non-polar organic solvents.

The problem is solved in that in the method of producing dispersions of carbon nanotubes, including functionalization of carbon nanotubes carboxyl and/or hydroxyl groups, and the subsequent processing of functionalized nanotubes in an organic solvent by ultrasonic treatment in an organic solvent ultrasound is carried out in the presence of reaction products of tetrabutyltin with stearic or oleic acid.

The ultrasonic treatment is carried out at a temperature from 40°C to the boiling point of the solvent.

The optimal condition for the chemical binding of the specified substances modifier to the surface of carbon nanotubes are a temperature of not lower than 40°C. the Upper temperature limit is limited by the boiling point of the employed solvent.

The most effective dispersion of carbon nanotubes in the presence of these oligomeric organic titanates by using clicks the processing ultrasound. However, it is possible to convert a mix of mechanical energy in devices such as bead mill, vibrating mill, homogenizer different types.

Nature CNS groups in oligomeric organic titanate does not play a significant role for the implementation of the claimed invention, because all CNS group associated with the atom of titanium, have the ability to react with carboxylic acids, carboxylic groups on the surface of solid particles, and, in exchange reactions with hydroxyl groups on the surface of solid particles. Therefore, the choice of the source alkylsilane used for the synthesis of oligomeric organic titanate, is determined by availability and cost. As the most affordable can be applied tetrabutyltin, it is soluble in organic solvents, oligomers and oligomeric reaction products of tetrabutyltin or its oligomers with fatty acids. With the same success can also be applied tetraisopalmitate. The selection of the fatty acid is also determined by the availability and low cost, and stability under conditions of application of modified carbon nanotubes. In most cases, can be applied stearic acid. Can also be applied oleic acid, however, due to the presence of a double bond, it may enter into side reactions at high temperature, especially in the presence of oxygen. On the other hand, this increased reactivity residue of oleic acid may be useful if further chemical modification or if the goal is to achieve chemical crosslinking of nanotubes with the polymer matrix.

Synthesis of oligomeric organic titanates containing CNS group and residues from fatty acids, may be conducted by various methods, for example by reaction of tetraallylsilane with fatty acid at elevated temperature. Conditions for this process are described in the literature U.S. patent 2621193. However, oligomeric organic titanates such a structure can be also synthesized by the reaction of the oligomeric alkylsilanes (previously obtained by a controlled hydrolysis or thermal decomposition of tetraalkylammonium) with fatty acids, as described in Kirk-Othmer Encyclopedia of Chemical Technology. All oligomeric organic titanates of this type, regardless of the synthesis method suitable for the implementation of the claimed invention, provided that these compounds are soluble and contain CNS group and the remains of fatty acids.

For realization of the invention it is not necessary to use pure fatty acids. Can be used technical the definition mixture of synthetic fatty acids, obtained by oxidation of paraffin hydrocarbons.

As theoretically possible alternative to fatty acids can also be applied resin acids rosin or other carboxylic acid containing a sufficiently large hydrocarbon residue.

The following are the data demonstrating the ability of the proposed method and its effectiveness.

For carrying out the invention was applied following the initial substance.

Carbon nanotubes tunic with conical orientation of the carbon layers, production LLC Nanocenter Tambov, was characterized by an outer diameter of 20-70 nm and a length of more than 2 μm. To eliminate the agglomeration of these nanotubes additionally to grind initially dry in the cage, then in a bead mill in suspension in water, filtered and dried.

Carbon nanotubes Taunit-M with cylindrical orientation of the carbon layers, production LLC Nanocenter was characterized by an external diameter of 8 to 15 nm and a length of more than 2 μm.

For functionalization of carbon nanotubes taunt and Taunit-M carboxyl and hydroxyl groups were treated with a solution of ammonium persulfate with the addition of ammonia, washed with water and dried.

For dispersion of the nanotubes used ultrasonic installation of IL-10 on 50% power. Processing of suspensions of ultratv the lump was performed in several stages with intermediate cooling, to avoid excessive overheating of solutions.

Tetrabutyltin synthesized according to known methods described, for example, the article in the Kirk-Othmer Encyclopedia of Chemical Technology. The titanium tetrachloride mark H was dissolved in n-butanol grade analytical grade, missed ammonia to saturate when cooled reaction mixture was filtered, the resulting ammonium chloride without access of air moisture, and then drove an excess of ammonia with n-butanol in a stream of argon.

Oligomeric organic titanate containing butoxyl group and the remains of stearic acid was synthesized analogously to the procedure described in example 7 of U.S. patent 2621193.

Example 1. Synthesis of oligomeric organic titanate containing butoxyl group and the remains of stearic acid. In weighted round-bottom flask with a capacity of 250 ml per thin section NTTT put 11,88 g (0,0349 mol) of tetrabutyltin (TBT)was added to 98 ml of toluene grade analytical grade, then 19,86 g (0,0698 mol) of stearic acid. Gathered distillation apparatus, and the reaction mixture was loaded Teflon tube for purging with argon. All connections carefully condensed PTFE sealing material, to prevent access of moisture to the air. With stirring in a stream of argon (at the beginning of 0.2 l/min, then 0.5 l/min, and in the end 0,9 l/min) was heated flask with the reaction mixture in glycerol bath until p is stvorenie stearic acid and then in a stream of argon drove volatile substances (toluene and n-butanol), slowly heating the flask in a glycerin bath, the final bath temperature was 130°C. the Whole process took about one and a half hours. Weight of non-volatile residue in the flask (brownish viscous liquid) was 25,81, Upon cooling, solidifies to a waxy mass. The melt of the substance at 40°C was extracted three times with 40 ml of acetone (analytical grade), in which, according to the U.S. patent 2621193], titanates oligomer insoluble, but soluble by-product (Batistuta). Then drove acetone in a stream of argon, maintaining the bath temperature 55°C for 1 h Received 19,15 g of the target product, which at room temperature was a waxy mass, easily soluble in n-heptane, toluene and practically insoluble in acetone.

Example 2. Synthesis of oligomeric organic titanate containing butoxyl groups and residues of oleic acid.

The synthesis was carried out analogously to Example 1, but instead of stearic acid took equimolar amount of oleic acid. The product was a brownish viscous liquid.

Example 3 (example for comparison). Attempt to obtain a dispersion of carbon nanotubes Taunit in toluene by using functionalized nanotubes.

In this example, took defunctionalization carbon nanotubes taunt to eliminate agglomeration processed in de the integrator in the bead mill. In beaker 150 ml was placed 2 g of organic titanate, obtained according to Example 1 and dissolved in 98 ml of toluene, then added 2 g of these nanotubes. The mixture was treated with ultrasound in total for 1 h with intermediate cooling. Got muddy black suspension containing visible aggregates of particles (flakes). With time of the suspension fell sediment. Thus, from defunctionalizing carbon nanotubes cannot obtain a stable dispersion, using as a dispersant oligomeric organic titanate containing butoxyl group and the remains of stearic acid. Moreover, the particles in this system had a tendency to stick to the walls of the glass, which was not observed when the dispersion Tunica in toluene without the addition of any dispersant. Apparently, if the original nanotubes do not contain on its surface carboxyl or hydroxyl group, organic titanate is adsorbed on the surface of the carbon stearate groups, while polar butoxyl groups are facing outwards, resulting in poor wetting of non-polar solvent. Thus, the attempt to direct the use of oligomeric organic titanate containing butoxyl group and the remains of stearic acid, for dispersion in narodnih nanotubes in toluene, does not lead to success.

Example 4. Obtaining a dispersion of carbon nanotubes Taunit in toluene.

In beaker 150 ml was placed 2 g of organic titanate, obtained according to Example 1 and dissolved in 98 ml of toluene, then added 2 g of functionalized carbon nanotubes taunt. The mixture was treated with ultrasound in total for 1 h with intermediate cooling. Got a black liquid that does not contain sediment and visible aggregates of particles (flakes). The solution was stable during storage. Thus, functionalized carbon nanotubes Taunit possible to obtain a stable dispersion with a concentration of 2 g of carbon nanotubes in 100 ml of a non-polar solvent, using as a dispersant oligomeric organic titanate containing butoxyl group and the remains of stearic acid.

Drop the obtained dispersion when diluted in an excess of n-heptane or toluene gave yellow solution without agglomerates, stable during storage.

Example 5. Obtaining a dispersion of carbon nanotubes Taunit in toluene.

The experiment was carried out analogously to Example 4, but as an organic titanate applied the product obtained according to Example 2 (containing residues of oleic acid instead of stearic). Got a stable black clear solution of nanotubes is to taunt, in the same way as in Example 4.

Example 6. Obtaining a dispersion of carbon nanotubes Taunit-M in toluene.

In beaker 150 ml was placed 0.5 g of organic titanate, obtained according to Example 1 and dissolved in 49.5 ml of toluene, then added 0,250 g functionalized carbon nanotubes tounit) and the Mixture was treated with ultrasound in total for 0.5 h with intermediate cooling. Got a black liquid that does not contain sediment and visible aggregates of particles (flakes). The solution was stable during storage. Thus, functionalized carbon nanotubes Taunit-M possible to obtain a stable dispersion with a concentration of 0.5 g of carbon nanotubes per 100 ml of non-polar solvent, using as a dispersant oligomeric organic titanate containing butoxyl group and the remains of stearic acid.

Drop the obtained dispersion when diluted in an excess of n-heptane or toluene gave yellow solution without agglomerates, stable during storage.

For the implementation of the proposed method there is no need to allocate oligomeric organic titanates in pure form. With the same success it is possible to use the reaction mixture of the reaction products of tetrabutyltin with fatty acid, which may also contain some amount of by-product is in n-butanol and butyl ether fatty acids, as described in Example 7.

Example 7. Obtaining a dispersion of carbon nanotubes Taunit-M in toluene, with application of the crude reaction mixture of the reaction products of tetrabutyltin and stearic acid.

In a tapered cone with a capacity of 50 ml was injected 20 ml of analytical grade toluene and added 5 g (0,0147 mol) of tetrabutyltin. In another cone dissolved 4,18 g (0,0147 mol) of stearic acid in 21 ml of toluene by heating to 30°C. the Solution tetrabutyltin quickly added to a solution of stearic acid and mixed. To complete the reaction, the reaction mixture has stood for two days at room temperature in a tightly closed cone (for protection against access of moisture in the air).

In a glass with a capacity of 100 ml was placed a portion 0,500 g of carbon nanotubes Taunit processed in a bead mill and functionalized by oxidation with ammonium persulfate in an ammoniacal aqueous solution. Added and 47.5 ml of analytical grade toluene, 2.5 ml of toluene solution of the crude titanate, obtained as described above, and treated with ultrasound for a total of 30 min ULTRASONIC, taking breaks to cool the mixture. During ultrasonic processing, the temperature of the mixture ranged from 40 to 70°C. Got a black transparent solution without precipitate, stable during storage. The molar ratio of fatty acid and tetraallylsilane used DL is getting treated or untreated oligomeric alkylsilanes, containing residues of fatty acids, is not the essential feature of the claimed invention, as can be taken from known data. Conducted experiments with oligomeric organic titanates obtained when the molar ratio of fatty acid to tetrabutyltin 1:1 or 2:1, but other ratios that can be selected from the published data.

The mass ratio of oligomeric organic titanate containing CNS group and the remains of fatty acids, functionalized nanotubes is not the essential feature of the claimed invention because it can be calculated theoretically. Optimally, to 1 hydroxyl group (including carboxyl) on the surface of functionalized nanotubes had 1 CNS group oligomeric titanate. Since the content of functional groups on the surface of carbon nanotubes can be defined by the known methods (acid-base titration, x-ray photoelectron spectroscopy, mass Spectro-metric analysis), and the content of CNS groups in the oligomeric titanate easily calculated from the mass balance of the reaction of its receipt, to calculate the ratio of the titanate and nanotubes is not difficult. However, a positive effect is achieved when the excess titanate.

Re the Ktsia CNS groups, attached to the titanium with carboxyl groups occurs quickly enough. However, in order to guarantee the passage of chemical reactions vaccinations oligomeric titanate to the surface of functionalized carbon nanotubes preferably heating the mixture to a temperature from 40°C to the boiling point of the solvent. When using a sufficiently powerful ultrasonic generator heating is not a separate process, because it automatically under the action of ultrasound on the variance. You only need to be careful not to overheat the mixture to the boiling point of the solvent. The ultrasonic treatment is preferably carried out without access of air moisture.

Thus, the claimed invention can be used to obtain stable dispersions of carbon nanotubes in various non-polar and monopolarly organic solvents, as well as for the introduction of carbon nanotubes in non-polar organic polymers.

1. The method of producing dispersions of carbon nanotubes, including functionalization of carbon nanotubes carboxyl and/or hydroxyl groups and subsequent processing of functionalized nanotubes in an organic solvent ultrasound, characterized in that the processing in an organic solvent ultrasound is carried out in the presence of the products is eacli of tetrabutyltin with stearic or oleic acid.

2. The method according to claim 1, characterized in that the ultrasonic treatment is carried out at a temperature from 40°C to the boiling point of the solvent.



 

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3 cl, 2 tbl, 5 ex

FIELD: process engineering.

SUBSTANCE: invention can be used in machine building, aircraft engineering and automotive industries, etc. Proposed method comprises application of plaster on steel part surface under normal atmospheric conditions, said plaster being composed of coagulated nanodiamond powder particles of 200-250 nm size mixed with thick graphite lubricant. Then, steel surface ply is subjected to electromechanical processing to produce ferrite-sorbite-fine perlite structure. Graphite nanostructured ply is formed on steel surface, said ply being sintered with nanodiamond to get common hardened 1.2 mm deep ply.

EFFECT: higher tribotechnical parameters and wear resistance of coated parts.

4 dwg, 1 tbl

FIELD: oil and gas industry.

SUBSTANCE: in order to receive modified bitumen raw stock is treated by vacuum distillation of fuel oil in the vacuum distillation unit at residual pressure at the unit top of 15-25 Hg mm. The produced tar oil with content of paraffin-napthene hydrocarbons of 12-23 wt % is delivered to a buffer tank, where it is mixed with 10-30% of bituminous compound coming from the oxidizing reactor upper part and plasticiser in quantity of 5-15% of the total mass of the raw stock; the plasticiser represents a product of reaction of 15.0-15.5 wt % of styrene, 2.4-4.0 wt % of cyclohexanone peroxide, 3.1-6.0 wt % of styrenic solution of cobalt salts of synthetic fat acids C7-C9, and remaining part of overoxidized bitumen. Then the produced mixture with temperature of 170°C at least is delivered to the middle part of the oxidizing reactor under grid and valve tray, where air mass in volume up to 160 m3/t is delivered simultaneously with the raw stock; at that oxidation reaction in the primary oxidation zone is carried out at temperature of 215-230°C during 8-35 minutes in film mode with its further decreasing. Bitumen produced in result of oxidation is delivered to the lower bottom part of the oxidizing reactor wherein sulfur melt in quantity of 3-60% of the bitumen mass is supplied simultaneously; at that temperature in the bottom part is maintained at the level of 160-190°C, thereafter the produced oligomer-sulfur-bitumen is outputted from the lower part of the oxidizing reactor.

EFFECT: bitumen has improved adhesion and cohesion properties and a wide range of plasticity as well as lower brittleness point.

1 tbl

FIELD: chemistry.

SUBSTANCE: invention can be used in making catalyst supports, sorbents, electrochemical catalysts and lithium-ion batteries. The method includes reacting, at 700-900°C, a calcium salt, e.g., calcium tartrate or calcium tartrate doped with a transition metal, which is a template precursor, and liquid or gaseous carbon-containing compounds or mixtures thereof as a carbon source. The obtained product is treated with hydrochloric acid. Concentration of the doped transition metal is not more than 1 at%.

EFFECT: obtaining a homogeneous mesoporous carbon material characterised by specific surface area of 850-930 m2/g, pore volume of 2,9-3,3 cm3/g and average pore diameter of 10-30 nm.

4 cl, 3 dwg, 9 ex

FIELD: nanotechnology.

SUBSTANCE: invention relates to nanotechnology. The graphene structures in the form of flat carbon particles with the surface of up to 5 mm2 are obtained by burning in air atmosphere or inert gas of composite press material produced from micro- and nanodisperse powders of active metals such as aluminium, titanium, zirconium, nanodisperse powders of silicon or aluminium borides taken in an amount of 10-35 wt %, and fluoropolymers such as polytetrafluoroethylene or a copolymer of tetrafluoroethylene and vinylidene fluoride, taken in amount of 90-65 wt %.

EFFECT: increased yield of graphene.

3 tbl, 4 dwg, 5 ex

FIELD: process engineering.

SUBSTANCE: invention relates to powder metallurgy, particularly, to production of nanocrystalline magnetically soft powders. It can be used for production of high-efficiency electromagnetic protection systems built around radio wave absorbing materials. Initial material, an amorphous band of magnetically soft alloys is subjected to heat treatment at the temperature (0.35-0.37)Tliquidus for 30-90 minutes and, then, cooled in air. Heat treated band is ground in high-rpm disintegrator to nanocrystalline powder with fraction size of 15-35 mcm.

EFFECT: higher efficiency of production at high magnetic permeability.

FIELD: metallurgy.

SUBSTANCE: method of iron powder production involves preparation of iron-carbon melt with the carbon content of 3.9-4.3 wt %, its spraying into water by compressed air, dehydrating, drying to produce raw powder with the proportion of concentration of oxygen to carbon being equal to 1.1-2.0, and grinding down to the particle size of maximum 0.250 mm. The ground raw powder is mixed with granulated iron oxides produced from waste rolling muriatic pickling solutions, with the concentration of impurities of maximum 2 wt % and granule size of maximum 0.160 mm. Concentration of granulated iron oxides in the mix with iron powder is determined, then the obtained mix is annealed in a furnace under the temperature of 950-1000°C for 1.5-2 hours in the layer of 25-35 mm high on a continuously moving band, crushing with the isolation of proper fraction of iron powder with the particle size of less than 0.200 mm.

EFFECT: production of high quality iron powder with high chemical purity, satisfactory fluidity, high compressibility and increased strength of pressing.

2 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a matrix carrier composition for use in a pharmaceutical delivery system for oral administration, which is a suspension consisting of particles of a material in a continuous oil phase. The material consisting of particles comprises a first solid phase comprising silicon dioxide nanoparticles having hydrophobic surface, with particle size of 5-1000 nm, and a second solid phase comprising a biopolymer having hydrophilic and hydrophobic parts, said biopolymer containing polysaccharide. Said continuous oil phase is associated with the first and second solid phases, and the weight of the biopolymer is double that of the silicon dioxide nanoparticles. The invention also relates to a method of producing a matrix carrier composition, which includes mixing a first solid phase comprising silicon dioxide nanoparticles with oil, activating a second solid phase containing polysaccharide, wherein activation includes grinding, vacuum treatment, chemical treatment or ultrasonic treatment, adding said activated second solid phase to the oil and mixing the oil containing the first solid phase and oil containing the activated second solid phase.

EFFECT: improved efficiency and bioavailability of a medicinal agent encapsulated in a matrix carrier.

13 cl, 3 dwg, 1 tbl, 8 ex

FIELD: metallurgy.

SUBSTANCE: proposed method comprises making the mix of titanium and lithium compounds to be heat treated, heat treatment products being annealed. Beforehand, said titanium tetrachloride solution is subjected to salt hydrolysis in boiling solution of said tetrachloride at 120÷150°C. Then, formed pulp is filtered to flush obtained precipitate with solution of alkaline agent. The latter is selected from the group consisting of ammonia carbonate, ammonia hydroxide, lithium carbonate, lithium hydroxide. Now, it is flushed with water and dried. Lithium compound with titanium and lithium is selected from the group including: lithium carbonate, hydroxide, oxalate, acetate and mixes thereof. Then, heat treatment is performed at 400-500°C under pyrolysis conditions. Annealing of heat treated mix at conducted at 800-900°C for 5 hours.

EFFECT: simplified production of nanosized particles of spinel-structure powders of lithium titanate Li4Ti5O12.

5 cl, 3 dwg, 2 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in manufacturing composites, containing organic polymers. A dispersion of carbon nanotubes contains 1 wt.p. of oxidised carbon nanotubes and 0.25-10 wt.p. of a product of interaction of organic amine, which contains in a molecule at least one hydroxyl group and at least one amino group, with tetraalkyltitanate.

EFFECT: dispersion is stable with the high content of nanotubes and minimal content of ballast substances.

8 ex

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