Method of obtaining of magnetically susceptible water soluble hydrophobically modified polyacryleamides and magnetic liquid based on them

FIELD: chemistry.

SUBSTANCE: polyacryleamides are obtained by heterophase copolymerisation of vinyl monomers. First, n-dodecyclacrylamide is added to water solution of sodium dodecylsulfate, applied as stabiliser, with mixing. Then, water solution of acryleamide and acrylic acid is added to obtained dispersion. Reaction is carried out in alkaline medium at pH 9.5 with general concentration of copolymers from 3.0 to 3.8 mol/l. After that, particles of magnetic filler are added to obtained mixture with mixing in atmosphere of inert gas with gradual increase of reaction mass temperature from 20 to 55°C. Water solution of initiator, such as potassium persulphate or ammonium persulphate is added to obtained water dispersion to concentration 3.5-4.2 mmol/l. After that, obtained product is separated by known methods. As magnetic filler, applied is magnetite with particle size from 50 to 1000 nm or acicular particles of magnemite from 200 to 800 nm long with diameter from 20 to 50 nm. Magnetic liquid includes liquid phase - water or its mixture with organic solvents, such as ethanol methanol, and magnetic solid phase - upper said polyacryleamide.

EFFECT: invention makes it possible to obtain polyacryleamide by more technological economic method in absence of highly-toxic solvents and obtain magnetic liquid, which preserves sedimentation stability in magnetic field.

4 cl, 1 dwg, 1 tbl, 7 ex

 

The present invention relates to a method for producing hydrophilic magnetospirillum polymers, namely magnetospirillum water-soluble hydrophobically modified polyacrylamides comprising particles of a magnetic filler - oxides, Fe3O4and γ-Fe2O3, submicron size, as well as to obtain a magnetic fluid based on them.

Adding these polymers in water or its mixture with organic solvents (ethanol, methanol) is spontaneous formation of kinetically stable magnetic fluid is not subjected to phase separation under the influence of external magnetic field with an intensity of 1.4-7.4 EC.

The invention can most effectively be used in the oil industry for controlled under the action of the magnetic field of the processes of delivery and placement of magnetic fluids in the hydraulic fracturing of rocks (EMG), and also as a means of monitoring their location when pumping through the pipes, while in the well or in the crack.

Known methods for producing magnetic fluids by intensive mechanical mixing, for example, under the action of ultrasound, magnetic material filler with synthetic polymers [U.S. patents№3149996; 3228881; 3471415; 3725285; 4002804; Mendenhall, G. D. et al., J. Colloid Interface Sci., 1996, 184, 519], and with half the measures of natural origin, for example, xanthan gum, starch, carboxymethyl cellulose and other [U.S. patent No. 5670077 and 6475404; Josephson, L. et al., Magn. Reson. Imaging 1990, 8, 637; Molday, R. et al., J. Immunol. Methods 1982, 52, 353; Sjoren, C. E. etal., Reson. Imaging 1997, 15, 55].

A disadvantage of the known methods of obtaining magnetic fluids is the fact that their preparation requires intensive mechanical mixing in the factory and on site service is delivered ready magnetic liquid, a suspension of particles of magnetic particles in the carrier fluid, which occupies a large volume, which significantly increases its value because of the high cost of transportation.

A method of obtaining magnetic fluid by intensive mixing of concentrates consisting of particles of magnetic particles, corrosion inhibitors and thixotropic agents, in water or mixed solvents (water-organic solvent) [U.S. patent No. 6475404 B1].

The known method includes the preparation of concentrates mechanical agitation 90-99.9 wt.% magnetic filler, 0.1-10 wt.% corrosion inhibitor and 0.1-5 wt.% water-soluble thixotropic agent. As the magnetic filler use carbonyl iron, restored, carbonyl iron, iron alloys and mixtures thereof. As corrosion inhibitors used the form of the sodium nitrite, sodium nitrate, sodium benzoate, sodium tetraborate, phosphate ethanolamine or mixtures thereof. As thixotropic agents use derivatives of cellulose, polyethylene oxide, starch, polysaccharides, gums and their mixtures. To obtain a magnetic fluid specified dry concentrates are dissolved in water or mixed solvents under vigorous stirring.

Using the known method of dry concentrate that is mixed with water or mixed solvent before use, reduces transportation costs.

The disadvantage of this method is the low stability of magnetic fluids during storage, since the mechanical mixing is almost impossible to achieve uniform distribution of the magnetic particles of the filler in the polymeric matrix, and a magnetic liquid obtained by adding a liquid carrier to dry concentrates containing magnetic filler and thixotropic agent, will eventually lose coagulation and sedimentation stability. Another disadvantage of this method is the necessity to include in the dry concentrate corrosion inhibitor due to the potential for oxidative degradation incorporated magnetic particles, resulting in deterioration of the magnetic properties of the magnetic fluids [Bengele, H. H. et al., Magn. Reson. Imaging 1994, 12, 433; Josephson, L. et al., Magn. Reson. Imaging1988, 6, 647; U.S. patent No. 5492814, 1996; Papisov, M. I. et al., J. Magn. Magn. Mater. 1993, 122, 383]. Another disadvantage of this method is the need for intensive mixing of the dry concentrate with water or a mixed solvent, which increases the cost of obtaining magnetic fluid.

In the literature there is evidence that a uniform dispersion of particles in the polymeric matrix and protect them from degradation, for example, by creating on the surface of thin polymer membranes can be achieved with the introduction of magnetic particles of the filler in the polymer in situ during the polymerization, leading to magnetospirillum polymers [T. Gelbrich et al., Macromolecules, 2006, 39, 3469: R. Matsuno et al., Chem Mater., 2003, 15, 3; Dresco P. A. et al., Langmuir 1999, 75, 1945; U.S. patent No. 4358388; U.S. patent No. 4421660; U.S. patent No. 6866838].

Known methods for producing magnetospirillum polymers by grafting controlled radical polymerization in the presence of nanoparticles of magnetic particles [T. Gelbrich et al., Macromolecules, 2006, 39, 3469: R. Matsuno et al., Chem Mater., 2003, 15, 3]. According to these methods, the process of obtaining polymers is at least two steps: (1) surface modification of nanoparticles of Fe3O4by chemical interaction of surface hydroxyl Fe-OH groups with functional groups of the molecules of the components of the initiating system; (2) PR is Vivacia polymerization of monomers (2-methoxyethylmercury, styrene) through the "anchor" initiating groups on the mechanism of controlled radical polymerization. The resulting hybrid magnetovolume polymers adding liquid form with super-paramagnetic properties of stable dispersions in N,N-dimethylformamide and methanol.

The drawback of such methods is that they are multi-stage, as well as the fact that they are designed for processes of controlled radical polymerization. It is known that the number of monomers capable of polymerization by the mechanism controlled radical polymerization, is very limited. Widely used in the processes of production cheap and environmentally safe polymers based on acrylamide pretty hard to get by controlled radical polymerization mechanism "live" circuits, because such reactions are very sensitive to changes in pH of the reaction medium and are (to achieve high molecular weight products) for a long time [Thomas D. B. et al., Macromolecules, 2003, 36, 1436].

A method of obtaining magnetospirillum polymers according to the mechanism of free radical polymerization of vinyl monomers (methacrylic acid, hydroxyethylmethacrylate) in the presence of nanoparticles of Fe3O4diluted [Dresco P. A. et al., Langmuir 1999, 75, 1945]. In accordance with this known method the vinyl is the group of monomers chemically interact with the hydroxyl groups on the surface of nanoparticles of Fe 3O4[K. Wormuth, J. Colloid Interface Sci., 2001, 241, 366], providing vaccination polymer chains on the magnetite. Under the action of a crosslinking agent on the surface of the particle shell is formed from a chemically cross-linked gel, preventing not only the agglomeration of magnetic particles, but also their destruction in the oxidative degradation and/or biodegradation.

The disadvantage of this method is the formation on the surface of magnetic particles insoluble gel shell. For its destruction is required to enter additional destructive agents - destructors - in-hole, crack, and it is not automated and requires additional costs.

Magnetovolume polymers in the form of a polymer latex obtained by heterophase (suspension, emulsion) polymerization in the presence of micro - and nanoparticles of magnetic particles.

A method of obtaining a hydrophobic polymers based on vinyl aromatic monomers, particularly styrene, α-methylstyrene, ethylstyrene, tert-butylstyrene, vinyltoluene, by direct emulsion polymerization in the presence of nanoparticles of Fe3O4[U.S. patent No. 4358388]. According to this method, magnetic particles with a hydrophobic surface is dispersed in the solution of oil-soluble monomers and initiator in an organic solvent, and the resulting dispersion is mixed is with an aqueous solution of emulsifier.

Known to the introduction of hydrophilic nanoparticles of Fe3O4in a matrix of a hydrophobic polymer [U.S. patent No. 4421660]. According to a known method hydrophilic nanoparticles of Fe3O4is dispersed in an aqueous solution of the emulsifier, which gradually introduce a solution of oil-soluble initiator and a water-insoluble monomer in an organic solvent.

The main technical disadvantage of the known methods of carrying out polymerization in emulsions is the use of highly toxic, is not miscible with water, flammable organic solvents, including hexane, cyclohexane, octane, toluene, etc., disposal and recycling them for reuse increases the cost of the production process. In addition, their use may result in environmental pollution

A method of obtaining hydrophilic magnetospirillum polymers on the basis of hydrophobic derivatives of acrylamide - N-alkylacrylate or N,N-dialkylacrylamide by inverse emulsion copolymerization [U.S. patent No. 6866838]. This method was selected as a prototype.

According to the method prototype hydrophilic polymers containing nanoparticles of inorganic filler, in particular magnetic particles, with a diameter from 50 to 1000 nm, mainly from 100 to 200 nm, receive heterophase what Ameritania in invert emulsions, the continuous phase is an organic solvent, such as octane, and an aqueous solution of vinyl monomers, such as N-alkylacrylate or N,N-dialkylacrylamide, dispersed in the form of small droplets. The method consists of two stages: (1) preparation of a dispersion of magnetic particles in an organic solvent, such as octane, in the presence of lipophilic stabilizer; (2) the inverse emulsion polymerization of water soluble monomers under the action of thermal decomposition of an initiator such as potassium persulfate, and in the presence of crosslinking agents such as N,N'-methylenebisacrylamide. In the continuous phase in addition to the nanoparticles of magnetic particles, an organic solvent and emulsifier may contain a hydrophobic monomer, such as styrene and an oil-soluble initiator, such as DINITROL asuitable acid. The reaction formed a stable and redispersible dispersion of composite particles with hydrophilic shell of chemically cross-linked polymer core containing magnetic particles.

The disadvantage of the prototype is the need for additional stages of the preparation of a dispersion of nanoparticles of magnetic particles in the oil phase in the presence of stabilizers.

The disadvantages of the prototype also includes the necessity of using destructors to destroy hydrophilic is blocki of chemically cross-linked polymer.

The present invention is to develop a new, more technologically advanced one-step method of obtaining magnetospirillum water-soluble hydrophobically modified polyacrylamide (which resolves the above drawbacks and receiving magnetic fluid on the basis of such polyacrylamides.

The technical result is to create a new one-step method of obtaining magnetospirillum polymers by micellar polymerization in aqueous medium and receiving a magnetic fluid on the basis of such polymers, which does not undergo phase separation under the influence of external magnetic field with an intensity of 1.4-7.4 EC.

The problem is solved by a new method of obtaining magnetospirillum water-soluble hydrophobically modified polyacrylamide heterogeneous copolymerization of vinyl monomers in the presence of magnetic particles of the filler, to the aqueous solution of sodium dodecyl sulfate, used as a stabilizer, was added n-dodecylamine under stirring and then the resulting dispersion is added an aqueous solution of acrylamide and acrylic acid in an alkaline medium at pH=9.5 with a total concentration of comonomers from 3.0 to 3.8 mol/l, and then to the resulting mixture of particles of magnetic particles under stirring in the atmosphere is e inert gas at a gradual increase in the temperature of the reaction mass from 20 to 55°C, to the resulting aqueous dispersion type aqueous solution of initiator such as potassium persulfate or ammonium persulfate, to a concentration of 3.5-4.2 mmol/l and allocate the resulting product by known methods.

As the magnetic particles used magnetite with a particle size of from 50 to 1000 nm when its concentration in the polymer is from 20 to 60 wt.%. As specified magnetic particles used needle particles maghemite with a length of from 200 to 800 nm and a diameter of from 20 to 50 nm when its concentration in the polymer is from 20 to 60 wt.%.

Also the problem is solved ferrofluid, which includes a magnetic solid phase sensitive hydrophobically modified polyacrylamide, and as the liquid phase is water and its mixtures with organic solvents, such as ethanol, methanol, etc. when the next component content (wt.%):

hydrophobically modified polyacrylamides0.1-0.3
the liquid phase99.7-99.9

The invention is illustrated in Fig.1, which shows data comparing the sustainability of 0.15 wt.% aqueous dispersions of magnetic GM PAA in a magnetic field (7.4 EC).

Water-soluble magnetovolume hydrophobically modified polyacrylamides, sod is readie particle commercial iron oxide - Fe3O4and γ-Fe2O3produced by in situ micellar copolymerization of acrylamide with sodium acrylate (an) and N-dodecylamine (DDA) in the presence of magnetic particles of the filler - commercial iron oxides, Fe3O4and γ-Fe2O3, submicron size in the aquatic environment. The content in magnetospirillum polymers acrylamide links is to 88.5 89.0 mol.%, n-dodecylamine links from 1.5 to 1.0 mol.% and acrylate units - 10 mol.% parts of sodium acrylate. The content of the magnetic particles of the filler - commercial iron oxides, Fe3O4and γ-Fe2O3, submicron size ranges from 22 to 58 wt.% (based on polymer). Received magnetophosphenes hydrophobically modified polyacrylamide allocate deposition from water-methanol solution in a mixture of acetone-methanol. The selected polymer is dried in vacuum at room temperature to constant weight. Polymerization occurs both in solution and on the surface of particles of magnetic particles and results in polymers, in which the dispersed particles of magnetic particles covered with the polymer protective shell. Polymer protective coating prevents degradation of the magnetic particles of the filler and provides aggregate and sedimentation stability in water the environment.

Aggregate and sedimentation stability of magnetic fluids is due to the fact that in the process of synthesis magnetospirillum of hydrophobically modified polyacrylamides by in situ micellar copolymerization of acrylamide with sodium acrylate (an) and n-dodecylamine (DDA) in the presence of magnetic particles of the filler - commercial iron oxides, Fe3O4and γ-Fe2O3that is of submicron size in an aqueous environment, the formation of the polymer occurs not only in solution but also on the surface of particles of the magnetic filler. The resulting polymers are vodorastvorimye hydrophobically modified polyacrylamides, in which the dispersed particles of magnetic particles covered with the polymer protective shell. Adding these polymers in water polymer shell on the surface of the particles prevents agglomeration of the particles and thereby contribute to their more uniform distribution in the polymer matrix, aggregate saving and kinetic stability of magnetic fluid. On the other hand polymeric shell protects the particles of magnetic particles from oxidative degradation in the aquatic environment.

To the polymer shell prevented the adhesion of the magnetic particles of the filler, as polymers should be used water soluble hidrovo is but modified polymers, containing a sufficient number of hydrophobic groups, which provide steric stabilization of the particles and negatively charged parts of sodium acrylate for electrostatic stabilization. One of the possible types of hydrophobically modified polymers based on polyacrylamide represented by the following formula:

where R=-(CH2)nCH3, n=8, 11; X=-O-NH; Y=-H, -CH3.

As the magnetic filler in the present invention using magnetic materials with particles of micron size, which can act as a displacement vector of magnetic fluid under the influence of the magnetic field is controlled in the delivery and monitoring of location of magnetic fluids in oil production processes, as, for example, Fe3O4and γ-Fe2O3and so on

The proposed method for woodstork magnetospirillum of hydrophobically modified polyacrylamides and kinetically stable magnetic fluid can be used for controlled under the action of the magnetic field of the processes of delivery and placement of magnetic fluids in hydraulic fracturing, but also as a means of monitoring their location when pumping through the pipes in the borehole or in the crack.

The invention is illustrated graphics.

In Fig.1 shows pictures of the magnetic liquid is awn, containing 0.15 wt.% magnetospirillum hydrophobically modified polyacrylamide, before and after exposure to magnetic fields with intensity 7.4 EC.

The invention is illustrated by the following examples.

Example 1

Preparation of copolymer of acrylamide with DAA and an containing 1 wt.% magnetite (sample No. 2 in table).

To a solution consisting of 1.8851 g LTOs in 30 ml of bidistilled water, add 0.0850 g DDA. In the resulting dispersion solution is poured 2.1613 g of acrylamide and 0.2564 g of acrylic acid in 21 ml of water at pH 9.5. The pH value is set by adding 1.38 ml of 2.5 N aqueous NaOH solution. In the prepared reaction system load 0.6912 g of powder of Fe3O4(Aldrich). The mixture is stirred with a speed of 700 rpm in a stream of argon at the temperature of the reaction mixture to 55°C for 30 minutes After the complete dissolution of DDA in the resulting dispersion of particles of Fe3O4inject 0.5 ml, 0.57 mol/l aqueous solution of ammonium persulfate. After 3 hours of polymerization at 55°C, the copolymer is diluted with 100 ml of a mixture of bidistilled water and methanol (25 ml 75 ml). The obtained viscous solution was slowly poured to 500 ml of a mixture of acetone (400 ml) and 100 ml of methanol. The selected polymer is dried in vacuum at room temperature to constant weight.

Example 2

Preparation of copolymer of acrylamide with DAA and an containing 1 wt.% magnet is a (sample No. 3 in table).

To a solution consisting of 1.8861 g chipboard in 30 ml of bidistilled water, add 0.0857 g DDA and variance of 0.6426 g of powder of Fe3O4(Aldrich) in a solution 0.2052 g chipboard in 10 ml bidistilled water. In the prepared reaction system poured the solution being 2.1600 g of acrylamide and 0.2646 g of acrylic acid in 19.1 ml of water at pH 9.5. The pH value is set by adding 1.38 ml of 2.5 N aqueous NaOH solution. The mixture is stirred with a speed of 700 rpm in a stream of argon at the temperature of the reaction mixture to 55°C for 30 minutes After the complete dissolution of DDA in the resulting dispersion of particles of Fe3O4inject 0.5 ml, 0.57 mol/l aqueous solution of ammonium persulfate. After 3 hours of polymerization at 55°C, the copolymer is diluted with 100 ml of a mixture of bidistilled water and methanol (25 ml 75 ml). The obtained viscous solution was slowly poured to 500 ml of a mixture of acetone (400 ml) and 100 ml of methanol. The selected polymer is dried in vacuum at room temperature to constant weight.

Example 3

Preparation of copolymer of acrylamide with DAA and an containing 1 wt.% magnetite (sample No. 5 in table).

To a solution of 0.2630 g of acrylic acid in 10 ml bidistilled water at pH 9.5 add 0.6925 g of powder of Fe3O4(Aldrich). The pH value is set by adding 1.38 ml of 2.5 N aqueous sodium hydroxide solution. To the resulting dispersion was added with stirring 1.8851 D Is P 0.0851 g DDA and 30 ml of bidistilled water. In the prepared system solution is poured 2.1638 g of acrylamide in 18.3 ml of water at pH 9.5. The pH value of 9.5 set by adding 1.0 ml of 0.5 N aqueous NaOH solution. The mixture is stirred with a speed of 700 rpm in a stream of argon at the temperature of the reaction mixture to 55°C for 30 minutes After the complete dissolution of DDA in the resulting dispersion of particles of Fe3O4inject 0.5 ml, 0.57 mol/l aqueous solution of ammonium persulfate. After 3 hours of polymerization at 55°C, the copolymer is diluted with 100 ml of a mixture of bidistilled water and methanol (25 ml 75 ml). The obtained viscous solution was slowly poured to 500 ml of a mixture of acetone (400 ml) and 100 ml of methanol. The selected polymer is dried in vacuum at room temperature to constant weight.

Example 4

Preparation of copolymer of acrylamide with DAA and an containing 1 wt.% maghemite (sample No. 6 in table.)

To a solution consisting of 1.8221 g LTOs in 30 ml of bidistilled water, add 0.0856 g DDA and variance of 0.6678 g of powder of γ-Fe2O3(GNIHTEMOS) in solution 0.2039 g LTOs in 10 ml bidistilled water. In the prepared reaction system solution is poured 2.1639 g of acrylamide and 0.2588 g of acrylic acid in 19.1 ml of water at pH 9.5. The pH 9.5 set by adding 1.38 ml of 2.5 N aqueous NaOH solution. The mixture is stirred with a speed of 700 rpm in a stream of argon at the surface is to the temperature of the reaction mixture to 55°C for 30 minutes After complete dissolution of DDA in the resulting dispersion of particles of Fe3O4inject 0.5 ml, 0.57 mol/l aqueous solution of ammonium persulfate. After 3 hours of polymerization at 55°C, the copolymer is diluted with 100 ml of a mixture of bidistilled water and methanol (25 ml 75 ml). The obtained viscous solution was slowly poured to 500 ml of a mixture of acetone (400 ml) and 100 ml of methanol. The selected polymer is dried in vacuum at room temperature to constant weight.

Some characteristics of the magnetic GM PAA is shown in the table.

Example 5

Preparation of magnetic fluid by dissolving the copolymer of acrylamide with DAA and an containing 1 wt.% magnetite (sample No. 2 in table), in water

0.1 g of a copolymer of acrylamide with DAA and an containing 1 wt.% magnetite (sample No. 2 in table), pour 99.9 ml bidistilled water and leave to swell at room temperature, and then stirred by a mechanical stirrer with a speed of 700 rpm

Example 6

Preparation of magnetic fluid by dissolving the copolymer of acrylamide with DAA and an containing 1 wt.% magnetite (sample No. 2 in table), 2 wt.%-nom water-ethanol solution

0.1 g of a copolymer of acrylamide with DAA and an containing 1 wt.% magnetite (sample No. 2 in table), pour 99.9 ml of 2 wt.%-wow ethanol-water solution and allowed to swell at room temperature, and C is the is stirred by a mechanical stirrer with a speed of 700 rpm

Example 7

Check the stability of magnetic fluids under the action of magnetic field

Study the effect of magnetic field on the phase state of aqueous dispersions of magnetic copolymers when the mass concentration in the solution is not less than 0.15 wt.% and the content of magnetic particles 0.007 wt.% carried out by exposure to a constant magnetic field of 7.4 EC for 24 h at room temperature. As can be seen from Fig.1, the aqueous dispersion magnetospirillum GM PAA does not undergo phase separation under the influence of a magnetic field.

The proposed method for magnetospirillum water-soluble hydrophobically modified polyacrylamide is superior to the prototype because it does not require the use of highly toxic, is not miscible with water, flammable organic solvents, including hexane, cyclohexane, octane, toluene, etc., disposal and recycling them for reuse increases the cost of the production process. In addition, their use may result in environmental pollution.

Offer magnetophosphenes water-soluble hydrophobically modified polymers are preferably polymers described in the prototype, the fact that the polymer shell on the surface of particles of magnetic particles is formed in polymerizes and chemically adsorbed on the particles of the monomers and is a water-soluble polymer, not chemically cross-linked gel, the destruction of which need special destructors.

In addition, the inventive magnetic fluid obtained spontaneously adding polymers in a liquid that does not require intensive mixing. The obtained magnetic fluid aggregately stable and retain sedimentation stability in the magnetic field of 1.4-7.4 EC.

Thus, the claimed method of obtaining magnetospirillum water-soluble hydrophobically modified polyacrylamide by micellar polymerization is more efficient compared to the prototype, as it eliminates the use of flammable organic solvents, the claimed method is carried out in aqueous medium at one stage, during which the surface of magnetic particles is formed of a polymeric shell, to destroy which does not require special destructors. The economic effect in this case is achieved by reducing the cost of using expensive equipment needed to work with easily flammable liquids and waste the last.

For technical and economic advantages of the claimed magnetic fluid is spontaneous dissolution magnetospirillum water-soluble hydrophobically modified polyacrylamide in water and in mixed solvent, to avoid the cost of phase dispersion of magnetic particles in the carrier fluid in the presence of stabilizers, which requires the use of expensive equipment.

1. The method of obtaining magnetospirillum water-soluble hydrophobically modified polyacrylamide heterogeneous copolymerization of vinyl monomers in the presence of particles of magnetic particles, wherein the aqueous solution of sodium dodecyl sulfate, used as a stabilizer, was added with stirring n-dodecylamine, then, to the resulting dispersion type aqueous solution of acrylamide and acrylic acid, and the reaction is carried out in an alkaline medium at pH 9.5 at a total concentration of comonomers from 3.0 to 3.8 mol/l, and then to the resulting mixture of particles of magnetic particles under stirring in an atmosphere of inert gas at a gradual increase in the temperature of the reaction mass from 20 to 55°C, the resulting aqueous dispersion type aqueous solution of initiator such as potassium persulfate or ammonium persulfate, to a concentration of 3.5-4.2 mmol/l and allocate the resulting product by known methods.

2. The method according to p. 1, characterized in that as the magnetic particles used magnetite with a particle size of from 50 to 1000 nm when its concentration in the polymer is from 20 to 60 wt.%.

3. The method according to p. 1, ex is different, however, as the magnetic particles used needle particles maghemite length from 200 to 800 nm and a diameter of from 20 to 50 nm when its concentration in the polymer 20-60 wt.%.

4. Magnetic fluid comprising a magnetic solid phase and the liquid phase, characterized in that the magnetic solid phase used magnetophosphenes hydrophobically modified polyacrylamide obtained by the method according to PP.1-3, and as the liquid phase using water and its mixtures with organic solvents, such as ethanol, methanol, etc. when the next component content (wt.%):

hydrophobically modified polyacrylamides0.1-0.3
the liquid phase99.7-99.9



 

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EFFECT: invention makes it possible to simplify obtaining the maghemite nanoparticles, increase the chemical stability of the obtained supermagnetic nanoparticles of a spherical shape with the size less than 10 nm.

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21 cl, 9 dwg, 7 tbl, 5 ex

FIELD: metallurgy.

SUBSTANCE: invention relates to production of electric steel. Proposed process comprises melting the steel of the following chemical composition, wt %: Si 0.1-1, Al 0.005-1.0, C≤0.004, Mn 0.10-1.50, P≤0.2, S≤0.005, N≤0.002, Nb+V+Ti≤0.006, Fe and unavoidable impurities making the rest. Steel bar ingot is produced and heated to 1150-1200°C. It is kept at said temperature for definite time and subjected to hot rolling at 830-900°C to steel strip. The latter is cooled to ≥570°C and coiled. Hot-rolled strip is straightened by cold rolling at reduction factor of 2-5%. Cold-rolled strip is continuously normalised at, at least 950°C and held thereat for 30-180 s. Normalised strip is etched and cold rolled with total reduction factor of 70-80% to get the sheet of target depth. Said sheet is annealed by heating at the rate of 100°C/s to 800-1000°C. It is held at this temperature for 5-60 s and slowly cooled down to 600-750°C at the rate of 3-15°C/s.

EFFECT: magnetic induction increased by at least 200 GSt.

2 cl, 3 tbl, 2 ex, 1 dwg

FIELD: metallurgy.

SUBSTANCE: proposed sheet can be produced on taking that a1 (mcm) makes the depth of insulation coat film at the depth of linear grooves and a2 (mcm) defines the depth of insulation coat film at steel sheet surfaces other than linear grooves when a1 and a2 satisfy the following equations: 0.3 mcm≤a1≤3.5 mcm and a1/a2≤2.5.

EFFECT: reduced local curling of coat film, high rust resistance and insulation properties.

2 cl, 1 dwg, 1 tbl, 1 ex

FIELD: electricity.

SUBSTANCE: method includes manufacturing of an alloy based on Nd-Fe-B, its hydrogen embrittlement, coarse grinding and subsequent fine grinding in a vibration mill using toluene as a protective medium. Lubricants are added to toluene before grinding, such as dry powders of aluminium stearates, or copper, or zinc, or ethyl ethers of homological row of carbonic acids. After grinding of the powder to the average size of particles 2.5-3.5 mcm it is loaded in dry or moist condition into a container from molybdenum and/or graphite with charging density from 3.0 to 3.5 g/cm3, and texturing is carried out with a pulse magnetic field with subsequent vacuum sintering of powders along with slow heating to temperature of not more than 500°C.

EFFECT: reduced forces of friction between particles of powder textured in magnetic field with subsequent formation of sintered magnets with high extent of texture by magnetic characteristics.

5 cl, 2 dwg, 7 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: polyacrylamide-based flocculant modification method includes using microwave radiation directed on the starting crystalline polyacrylamide product. The microwave radiation has the following properties: frequency 2.45 GHz, power 700 W, duration of irradiating crystals of the starting flocculant 5-7 s.

EFFECT: method creates conditions for further interaction of macromolecules with each other and increase in molecular weight thereof, which improves the process.

1 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: claimed invention relates to a method of obtaining heterogeneous mixture used in the paper industry. Described is the method of manufacturing heterogeneous mixture of polymers, including: (a) introduction into a solution of the first portion of a polymerisation initiator and one or several anionic or cationic monomers, with monomers carrying the same charge; (b) introduction into the solution of the second portion of the polymerisation initiator and one or several non-ionic monomers; (c) introduction of the third portion of the polymerisation initiator and one or several ionic monomers, whose charge is opposite to the charge of monomers from (a); (d) gradual introduction of the fourth portion of polymerisation initiator for a reaction of any remaining monomer with formation of a heterogeneous mixture of polymers; and (e) in case of necessity neutralisation of the obtained heterogeneous mixture of polymers, with anionic monomers being selected from the group, consisting of: (1) acrylic acid, (2) methacrylic acid, (3) styrene sulfonic acid, (4) vinyl sulfonic acid, (5) acrylamido methylpropane sulfonic acid and (6) their mixtures; cationic monomers are selected from the group, which includes: (1) diallyldimethylammonium chloride, (2) acryloylethyl trimethylammonium chloride, (3) methacryloylethyltrimethylammonium chloride, (4) acryloylethyltrimethylammonium sulfate, (5) methacryloyl ethyltrimethylammonium sulfate, (6) acrylamidopropyltrimethylammonium chloride, (7) methacrylamidopropyl trimethylammonium chloride, (8) non-quaternised forms (2)-(7), (9) vinylformamide (further hydrolised into vinylamine) and (10) their mixtures, and non-ionic monomers are selected from the group, consisting of: (1) acrylamide, (2) methacrylamide, (3) N-alkylacrylamide, (4) vinylformamide and (5) their mixtures. Also described is the heterogeneous mixture of polymers, intended for increasing the content of a filling agent in paper or carton, obtained by the method described above. Methods of increasing the content of the filling agent in a paper or carton sheet with application of the said heterogeneous mixture of polymers are described.

EFFECT: increase of the content of an inorganic filling agent in paper with simultaneous preservation of weight, strength and suitability of the final product for processing.

17 cl, 9 tbl, 14 ex

FIELD: chemistry.

SUBSTANCE: composite material can be used to produce sheet decorating and heat-insulating materials in residential, agricultural and industrial construction, as well as for producing moulded packaging elements and containers susceptible to biodegradation, i.e., having biodegradable properties. The polymer composite material consists of, wt %: fibre filler - waste cardboard and/or paper 11.0-12.0, cationic-anionic polyacrylamide resin Ultrarez DS-150 56.0-57.0, polyvinyl alcohol in form of a 15 wt % aqueous solution 27.0-28.0, sodium tetraborate 6.0-3.0. Described is a method of producing a composite material which involves separating fibres of the fibre filler on a rotary disperser with rotor speed of 2500-3000 rpm, wherein the polyvinyl alcohol is added at the mixing step in form of a 15 wt % aqueous solution together with the cationic-anionic polyacrylamide resin Ultrarez DS-150 and sodium tetraborate, pressing and drying.

EFFECT: improved physical and mechanical properties of the polymer composite material while simplifying the production technique.

2 cl, 3 ex

FIELD: chemistry.

SUBSTANCE: composite material consists of the following, wt %: polyethylene 277 50-55 and a copper polyacrylamide polycomplex 50-45. The copper polyacrylamide polycomplex is obtained by dissolving copper powder in ammonia solution, mixing the obtained solution with aqueous polyacrylamide solution and separating the polycomplex from the solution with acetone or ethyl alcohol.

EFFECT: longer service life of friction assemblies operating in a dry environment, high hardness of articles.

2 tbl

FIELD: oil and gas industry.

SUBSTANCE: suspension-emulsion composition of anti-turbulent additive contains the following, wt %: polyacrylamide with "м.м." 5.5·106 and particle size of not more than 200 mcm - 30-20, polyethyleneglycol - 11-13, stearic acid - 2, ethanol - 42-50 and glycerin - 15.

EFFECT: anti-turbulent additive has decreased viscosity and provides reduction of hydrodynamic friction in oil flow.

8 ex

FIELD: oil and gas production.

SUBSTANCE: method to stabilise an aqueous solution of polyacrylamide consists in preparation of polyacrylamide in water with concentration from 0.15 to 0.30 wt %. Then polyacrylamide is dispersed by mixing of the produced solution with angular speed from 14000 rpm to 17000 rpm.

EFFECT: method makes it possible to reduce energy intensity and time for solution preparation, to preserve rheological properties of a solution within a long period of time, to increase efficiency of using the produced solution due to stabilisation of its dynamic viscosity.

3 dwg

FIELD: chemistry.

SUBSTANCE: method of producing hybrid organic-inorganic material comprises the following steps: (a) peptisation of material of inorganic particles selected from oxides, sulphides, sulphates, phosphates, arsenides and arsenates of noble metals and mixtures thereof, in anhydrous sulphuric acid or hydrogen fluoride, to obtain a solution of material of inorganic particles; (b) fractionation of the solution obtained at step (a) to obtain a solution of inorganic particles having particle size ranging from 5 nm to 100 nm; (c) mixing the fractionated solution obtained at step (b) with an organic solvent; (d) reacting the mixture from step (c) with a solution of a reactive organic monomer with silane functional groups in an organic solvent.

EFFECT: method of obtaining hybrid organic-inorganic monomer material enables to obtain monomer materials which combine desired products of material of inorganic particles and an organic monomer, in addition to unique nanoparticle properties.

15 cl

FIELD: chemistry.

SUBSTANCE: silicone-hydrogel composition for soft contact lenses contains a silicone monomer N,O-bis(trimethylsilyl)acrylamide and 2-hydroxyethylmethacrylate, to which a water-soluble monomer N-vinyl-2-pyrrolidone or N,N-dimethylacrylamide is added to improve hydrophilic properties, as well as a cross-linking agent, such as ethylene glycol dimethacrylate or divinylbenzene, to improve hydrophilic properties, high content of water, high oxygen permeability, good elongation and optical transparency.

EFFECT: obtaining hydrophilic lenses with high content of water and high oxygen permeability.

7 cl, 2 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to a system of reagents for extracting paint materials from recycled water, based on acrylic, melamine, polyurethane, nitrocellulose, epoxy and alkyde film-forming agents and can be used in wood processing, machine building, motorcar and other industries. Disclosed is a flocculant consisting of (wt %) polyacrylamide (6-10), activating additive selected from aminotriazole, guanidine carbonate and semicarbazide (0.1-1.5), hydrazine hydrate (0.1-1.5) and water (the rest).

EFFECT: possibility of varying the structure of the obtained deactivated wastes of paint materials, which enables processing of paint material wastes for reuse or recycling with minimum expenses.

1 cl, 1 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an acrylic composition for plugging threaded joints, particularly for fixing high frequency connectors of inter-block cables. The acrylic composition consists of an acrylic amide-containing resin, an organic colour pigment and a solvent. The acrylic amide-containing resin is a copolymer of butylmethacrylate and acrylamide. The solvent used is a mixture of acetone, xylene and butylacetate. The acrylic composition has high adhesion to different metals, long working life and a wide range of working temperature from minus 40 to plus 50°C. The composition can be used on vertical surfaces.

EFFECT: use of the composition prevents self-unfastening of low-loaded threaded joints subjected to vibration loads and, if needed, enables dismantling of assembled elements.

1 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to a comb-shaped copolymer comprising: (A) one or more repeating units obtained from olefinically unsaturated cationic or cation-active comonomers; and (B) one or more repeating units of formula where Y is a moiety which forms part of the copolymer backbone and is obtained from a monomer selected from at least one of the following monomers: olefinically unsaturated cationic or cation-active comonomers, acrylamide monomers, one or more olefinically unsaturated hydrophilic monomers, one or more olefinically unsaturated monomers; Z is a moiety capable of forming an associate with another moiety Z or other moieties in the preparation in which the copolymer will be used, and is a hydrophobic moiety selected from alkyl, aryl, aralkyl, fluoroalkyl groups having 8-50 carbon atoms, an organosilicon group having 35-25 linked SiO moieties, and silane; and b is a bond or a moiety, linking the moiety Z with a moiety Y, and represents covalent bonds formed by at least one ester, carbonyl, amide, amine oxide, hydrocarbon, amino, ether, polyoxyalkylene groups, or a bond resulting from ionic salt bonds. The invention also describes a personal hygiene product and a composition for the personal hygiene product containing said comb-shaped copolymer.

EFFECT: obtaining a comb-shaped cationic copolymer, which provides a balance of the required properties when used in personal hygiene products and other cosmetic preparations in terms of the sensory perception thereof and the degree of deposition or retention of active ingredients.

25 cl, 13 tbl, 73 ex

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