4764 results about "Dimethyl formamide" patented technology

The present invention relates to a high modulus macroscopic fiber comprising single-wall carbon nanotubes (SWNT) and an acrylonitrile-containing polymer. In one embodiment, the macroscopic fiber is a drawn fiber having a cross-sectional dimension of at least 1 micron. In another embodiment, the acrylonitrile polymer-SWNT composite fiber is made by dispersing SWNT in a solvent, such as dimethyl formamide or dimethyl acetamide, admixing an acrylonitrile-based polymer to form a generally optically homogeneous polyacrylonitrile polymer-SWNT dope, spinning the dope into a fiber, drawing and drying the fiber. Polyacrylonitrile/SWNT composite macroscopic fibers have substantially higher modulus and reduced shrinkage versus a polymer fiber without SWNT. A polyacrylonitrile/SWNT fiber containing 10 wt % SWNT showed over 100% increase in tensile modulus and significantly reduced thermal shrinkage compared to a control fiber without SWNT. With 10 wt % SWNT, the glass transition temperature of the polymer increased by more than 40° C.

An improved process for chlorination of sugars produces chlorodeoxy derivatives, in particular the chlorination of sucrose-6-esters to produce sucralose (4,1′,6′-trichloro-4,1′,6′-trideoxy galactosucrose), with thionyl chloride and N,N-dimethyl formamide (DMF) at the ration of about 1 molar equivalent of thionyl chloride for every molar equivalent of free hydroxyl group.

The invention discloses a high-yield preparing method for inorganic halogen perovskite fluorescent quantum dots at the room temperature. The fluorescent quantum dots are CsPbX3, wherein X is equal to AxB1-x and is larger than or equal to 0 and smaller than or equal to 1, and A and B are any one of Cl, Br and I. The method comprises the following steps that firstly, lead halide and cesium halide are dissolved into dimethyl formamide, surfactant oleylamine and oleic acid are added, the mixture is stirred until complete dissolution, and a precursor solution is obtained; secondly, the precursor solution is dripped into a poor solvent at the speed of 0.08-0.13 mL/s and stirred evenly at the uniform speed, and the inorganic halogen perovskite fluorescent quantum dots CsPbX3 are obtained. The preparing method is implemented at the room temperature, protection gas is not needed, equipment is simple, mass production can be achieved, and full visible light band shining can be achieved by selecting halogen and adjusting the proportion of halogen. The full width at half maximum of the inorganic halogen perovskite fluorescent quantum dots prepared through the preparing method ranges from 16 nm to 39 nm, the fluorescence quantum efficiency is close to 90%, and the inorganic halogen perovskite fluorescent quantum dots can be stably stored for more than three months, and can be used in the field of solar cells, lasers, light detectors, light-emitting diodes and the like.

The invention relates to the fields of a novel chemical electric power source and a new energy material, and particularly discloses a graphene/molybdenum disulfide composite electrode material and a preparation method of the composite electrode material. The preparation method comprises the steps of: (1) preparing graphite oxide from graphite as a raw material by an oxidation and intercalation method; (2) dissolving prepared graphite oxide with deionized water, carrying out ultrasonic stripping to obtain a graphene oxide solution, then adding DMF (dimethyl formamide) and molybdate, finally adding a reducing agent, and dispersing uniformly to obtain a mixed solution; and (3) transferring the mixed solution to a reaction kettle, keeping the temperature in the temperature condition of greater than or equal to 180 DEG C for 5-10h, centrifuging and washing the product to remove DMF, and drying to obtain the graphene/molybdenum disulfide composite electrode material product. The preparation method of the graphene/molybdenum disulfide composite electrode material is simple, uniform in reaction system and low in production cost, and is particularly suitable for requirements of industrial large scale production; and the prepared product graphene/molybdenum disulfide composite electrode material has better electrochemical performances.

The present invention discloses preparation and application of perovskite nanowires, a photoelectric detector and a solar cell. A preparation method of the perovskite nanowires comprises: (1) dissolving iodinated methylamine and haloid of lead in dimethyl formamide solution to prepare lead-halide perovskite precursor solution; (2) carrying out ultraviolet and ozone treatment on a substrate for at least 30 minutes to obtain the substrate with hydrophilcity; (3) roughening the edge of one end of the substrate and dispensing or spraying the lead-halide perovskite precursor solution on the substrate; and then jacking up the roughened edge end to enable an included angle to be formed between the substrate and the horizontal plane, carrying out standing and heating the substrate to obtain the lead-halide perovskite nanowires. According to the present invention, the lead-halide perovskite nanowires which are uniform in density and are ordered in direction can grow in a selective region of the substrate; and moreover, the grown lead-halide perovskite can be well combined with other parts or preparation methods of existing devices (for example, the lead-halide perovskite can be combined with other parts of the existing devices into the photoelectric detector, the solar cell and the like), so that performance of the devices are improved.

The invention discloses high-strength high-thermal-insulation silica aerogel and a preparation method thereof. The preparation method comprises the following steps: modifying halloysite with amino-terminated polysiloxane; adding ethyl orthosilicate, absolute ethyl alcohol, hydrochloric acid, dimethyl formamide and ammonium hydroxide to ensure a reaction and obtain gel; finally, carrying out carbon dioxide supercritical extraction to obtain the silica aerogel. As hollow natural clay fiber halloysite which is high in mechanical strength, low in thermal conductivity and high in thermal stability is taken as a reinforcing phase, the silica aerogel prepared according to the preparation method is relatively high in porosity, relatively low in density, excellent in mechanical property, favorable in heat-insulating property and relatively high in heat resistance.

The invention discloses a method for preparing a grapheme/silver nanoparticles composite material by using a liquid phase method. N and N-dimethyl formamide (DMF) serve as a reducing agent, grapheme powder with purity as high as 99% serves as a carrier, and silver forms a core and grows on a grapheme layer under a soft reaction condition to obtain the grapheme/silver nanoparticles composite material. The preparation method has the advantages of being simple, convenient, rapid and high-efficient in process, the grapheme/silver nanoparticles composite material prepared by using the method is high in purity and less in impurity content, and silver nanoparticles generated on the surface layer of the grapheme are small in particle size, uniform in distribution and high in bond strength with the grapheme. The silver nanoparticles are closely absorbed on the grapheme layer, aggregation of the grapheme is effectively avoided, and application of the grapheme/silver nanoparticles composite material in the fields of electron, catalysis, antibiosis and the like can be enlarged.

The invention relates to the technical field of nano materials and specifically relates to amino-modified silica with dual drug-loading effects. According to the technical scheme, firstly, mesoporous silica nanoparticles are prepared by a template method; secondly, surface amino modification is carried out onto the mesoporous silica nanoparticles by 3-aminopropyltriethoxy silane; thirdly, ursolic acid is chemically coupled to the spherical mesoporous silica nanoparticles by amido bonds; and fourthly, the coupled nanoparticles are dispersed in DMF (dimethyl formamide) solution; a proper amount of ursolic acid is added, mixed and stirred; and finally vacuum drying is carried out to obtain the amino-modified silica with dual drug-loading effects. The mesoporous nano material with dual drug-loading effects prepared by the mesoporous silica disclosed by the invention is high in loading rate, can achieve controlled release effect for the loading drug ursolic acid, so that drug effect lasts for a long period time, and therefore, bioavailability of the ursolic acid is greatly improved.

The invention discloses a tetravalent platinum complex with a bioactive group and a preparation method of the tetravalent platinum complex. The tetravalent platinum complex is a platinum (IV) complex and has the structure shown in the formula II (please see the formula in the description), wherein in the formula II, Y is OH or Cl, and Bio represents the bioactive group. The platinum (IV) complex is prepared according to the equation in the formula III (please see the formula in the description), wherein in the formula III, Y is OH or Cl, Bio-OH represents a compound with bioactivity, TBTU represents a coupling agent O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, TEA represents a catalyst triethylamine, DMF represents solvent N,N-dimethyl formamide, and DMSO represents solvent dimethylsulfoxide. Cis-platinum is adopted for the bottom face of an octahedron, a small-molecular targeted or medicine active group is introduced to one axial position, a hydroxyl group or helium atom is introduced into another axial position, and the anti-tumor tetravalent platinum complex overcoming cisplatin resistance is provided, so the high-efficiency and low-toxin platinum (IV) complex is obtained.

The invention relates to a polyurethane-polypeptide graft copolymer and a preparation method thereof. The graft copolymer is a comb-shaped polymer, wherein the molecular weight of polyurethane is 10,000 to 100,000; and the molecular weight of the polypeptide chain segment is 500 to 5,000. The preparation method comprises the following steps of: 1) synthesis of polyurethane provided with lateral carboxyl on the molecular chain: adding diisocyanate, polypropylene glycol, polyethylene glycol, dibutyltin dilaurate catalyst and dimethyl formamide solvent into a dry reaction bottle, performing stirring reaction under inert atmosphere, adding dimethylolpropionic acid dissolved in dimethyl formamide to react, adding butanediol to react, finally adding butanol to react, and obtaining a target product; and 2) synthesis of the polyurethane-polypeptide graft copolymer: putting the polyurethane provided with lateral carboxyl on the molecular chain, a solvent and a condensation agent into a dry reactor, adding polypeptide homopolymer into the reactor, and performing stirring reaction under the inert atmosphere to obtain a target product with pH response.

The invention provides a phosphorus-contained organic silicon resin fire retardant shown as a following formula and a preparation method thereof. The preparation method of the phosphorus-contained organic silicon resin fire retardant comprises the following steps: firstly, adopting polyalcohol and phosphorus oxychloride as raw materials to prepare chlorinated volution phosphoester; then carrying out hydrolytic condensation on amino-containing silane, dialkoxy silane and trialkoxysilane to obtain amino-containing organic silicon resin; finally dissolving the amino-containing organic silicon resin into a methylbenzene solvent, an N,N-dimethyl fomamide solvent or an acetonitrile solvent, and the like, and adding the chlorinated volution phosphoester and an acid-binding agent for synthesis to obtain the phosphorus-containing organic silicon resin fire retardant. The phosphorus-containing organic silicon resin fire retardant can be used as a fire retardant for polyolefin, makrolan, ABS, nylon and PC/ABS, has high efficiency and low toxicity compared with the traditional fire retardant and is an environmental protection type fire retardant for plastics. R1, R2, R3 and R4 are respectively selected from CH3 or C6H5, R5 is selected from CH2 or CH2CH2 or CH2CH2NHCH2CH2, and R6 is selected from the CH3 or C2H5; n is equal to integers of 1 subtracting 50, P is equal to integers of 1 subtracting 50, and q is equal to integers of 1 subtracting 50.

The invention discloses a convenient method for preparing binder-free stannic oxide/carbon fibrofelt for a negative pole of a high-performance lithium ion battery. The method disclosed by the invention comprises the following steps: dissolving polyacrylonitrile and stannous chloride which have certain concentrations to a N'N-dimethyl formamide solution, magnetically stirring the solution of polyacrylonitrile, the stannous chloride and the N'N-dimethyl formamide solution until the solution is clarified, electrostatically spinning the solution, and finally annealing the obtained solution which is obtained at a high temperature twice to obtain Sn-SnOx uniformly loaded nanometer composite materials of the carbon fibrofelt. For a compound which is prepared by the method disclosed by the invention, since the electrostatic spinning method is adopted, nanometer particles of metal-metallic oxide are uniformly dispersed into buffer substrate carbon fiber, and the circulation specific capacity and the stability of materials for the negative pole of the lithium ion battery are effectively improved. The preparation technology disclosed by the invention has the advantages that the operation is simple, the cost is low, the efficiency is high, the large-scale and industrial production is easy to realize, and the application range is broad.

The invention discloses a method for producing real leather intimating polyurethane synthetic leather, which comprises the following steps: firstly, preparing a wet synthetic leather semi-finished product; secondly, coating a polyurethane finishing agent on the surface of the wet synthetic leather semi-finished product to perform printing surface treatment; thirdly, sticking a release paper pattern transferred polyurethane film to the surface of the printed wet synthetic leather semi-finished product, wherein raw materials in polyurethane slurry comprise polyester-polyether-polycarbon copolymerized polyurethane resin, cracking resin, dimethyl formamide, down powder, wet wax sensitive toner and solvent pigment; and finally, performing kneading treatment. The polyurethane synthetic leather has frosting effect on the surface, smooth handfeel, color change when pushing the surface by hand and strong third dimension of patterns, has good physical properties such as scratch resistance, cold resistance, hydrolysis resistance and the like, and can replace real leather in many aspects so as to reduce the requirement for furs, protect the nature and keep ecological balance.

A hydrophilic polyurethane dressing for wound is composed of the soft foam chips of hydrophilic polyurethane and the water-proof bacteria-isolating air and moisture permeable polyurethane film. Its preparing process includes such steps as mixing polygolyol, toluene diisocyanate (TDI-80) and propanetriol, stirring, reaction at 80-90 deg.C for 90-120 min to obtain prepolymer of polyurethane, mixingit with polyether, organotin catalyst, alamine catalyst pore-forming agent, stabilizer and water, foaming and ageing to obtain said soft foam chips, preparing the solution of said prepolymer in acetone and/or N,N-dimethyl formamide, adding water, filming, removing solvent, and solidifying reaction to obtain polyurethane film.

The invention discloses a metal/grapheme nanocomposite and a preparation method thereof. The method comprises a photo-reduction one-step method and a photocatalytic reduction one-step method. The photo-reduction one-step method comprises the steps as follows: a grapheme oxide and metal complex acid or inorganic salt and a photo-reduction agent are mixed at the room temperature or under the condition of an ice-water bath, and under the light condition, organic negative hydrogen donors reduce metal ions and the grapheme oxide, so that a product is obtained. One approach of the photocatalytic reduction one-step method comprises the steps as follows: the grapheme oxide and the metal complex acid or salt are mixed in a DMF (dimethyl formamide) water solution containing a reducing agent, a metal ligand and a photocatalyst or in a water solution, catalysis is performed through the catalyst under the light condition, and at the same time, the reducing agent reduces the metal ions and the grapheme oxide, so that a product is obtained; and the other approach of the photocatalytic reduction one-step method comprises the steps as follows: the grapheme oxide and a metal organic complex are mixed in a DMF water solution containing the reducing agent and the photocatalyst or in a water solution, then catalysis is performed through the catalyst under the light condition, and the reducing agent reduces the metal organic complex and the grapheme oxide, so that a product is obtained.

The invention discloses a method for preparing a G/Sn/PAN-base carbon nanometer fiber membrane. The method for preparing the G/Sn/PAN-base carbon nanometer fiber membrane includes: 1) preparing spinning solution, to be more specific, weighing polyacrylonitrile, nanometer tin powder and graphene nanometer film according to certain mass ratio, blending and dissolving in N-N dimethyl formamide, and stirring to obtain the uniformly dispersed electrostatic spinning solution; b) electrostatic spinning, to be more specific, carrying out electrostatic spinning on the electrostatic spinning solution of the step a) to obtain a graphene/tin/polyacrylonitrile nanometer fiber membrane; c) pre-oxidizing, to be more specific, pre-oxidizing the graphene/tin/polyacrylonitrile nanometer fiber membrane of the step b) in air atmosphere to obtain the pre-oxidized nanometer fiber membrane; d) carbonizing, to be more specific, carbonizing the pre-oxidized nanometer fiber membrane in argon atmosphere to obtain the G/Sn/PAN-base carbon nanometer fiber membrane. The method for preparing the G/Sn/PAN-base carbon nanometer fiber membrane is easy to operate, the graphene coats the nanometer fiber well; the G/Sn/PAN-base carbon nanometer fiber membrane has advantages of large specific surface area, high porosity, and high electrical conductivity and so on, and has broad expanding space.

A polyacrylnitrile-base carbon fibre spinning liquid is prepared from acrylnitrile, dimethyl formamide, distilled water, azodiisobutylnitrile and chain transfer agent through homopolymerization, introducing ammonia gas to stop reaction, and regulating pH value by ammonia gas. Its advantages are uniform distribution of function groups on macro-molecular chain, simple process and easy control.

The invention discloses a method for preparing quaternary amine salt ion adsorbent by using a plant with high cellulose content. Straw stalks with high cellulose content, epichlorohydrin and tri-ethylamine are taken as raw materials, ethylene diamine, diethylene triamine pentacetic acid (DTPA) or triethylenetetramine, etc are used as crosslinking agent to prepare the adsorbent under the condition of existence of N, N-dimethyl formamide. The method has the advantages of simple process, low cost, economic and practical, reproducible, etc. The adsorbent prepared by the method has the advantages of high liveweight growth rate, low secondary pollution, high stability, sound adsorption effect, wide application scope, etc; and the adsorbent can be extensively applied to the treatment of eutrophication of waters.

Disclosed is a method for making pH sensitive PVDF hollow fiber intelligent film and products made thereby, wherein the making process comprises the steps of, (1) steeping the film in pure water for 24 hours, (2) preparing 10-20% alkali solution, and charging 3-4gl/L of tetrabutylammonium bromide, charging immersed film in alkali solution, heating by water bath, (3) preparing 1-2 mol/L of AAC solution, charging dimethyl formamide solution by 40-50ml/L, mixing uniformly, charging alkali-treated film in the mixed solution, steeping 10-20 minutes at room temperature, preparing solution of crosslinking agent 0.01-0.09mol/L and K2S2O3 0.1-0.3g, charging the readily made film into the solution, filling N2 and sealing, water-bathing, heating and washing with deionized water, the crosslinking agent is MBAA or diacrylic acid ethylene glycol ester.

The invention discloses a preparation method for a high-dielectricity polyvinylidene fluoride/poly-dopamine-coated graphene nanocomposite. The method comprises the following steps: graphene oxide is prepared through a Hummers oxidation method, dopamine is automatically polymerized under the alkaline condition to coat the surface of the graphene oxide, reduction is performed on the poly-dopamine graphene oxide through hydrazine hydrate, centrifugal washing is performed repeatedly for removing impurities, the obtained poly-dopamine-coated grapheme can disperse in N, N-dimethylformamide well after being subjected to ultrasonic treatment, the polyvinylidene difluoride and the poly-dopamine-coated graphene are mixed through a solution method, and hot press molding is performed on the mixture, so that the nanocomposite is obtained. The preparation process is simple and easy to operate, the repeatability is good, the composite is good in flexibility and machinability, and has high potential for being applied to dielectric materials of energy storage parts such as capacitors.

The invention relates to a preparation process of a metal-organic framework porous adsorption material for C4-C8 normal paraffin and isoparaffin adsorption separation. According to the preparation method of the synthesized metal-organic framework porous adsorption material, metal ion nitrate and an organic ligand are dissolved according to the mass ratio of 1:1-15 in a mixed solution of N,N-dimethylformamide and N,N-diethyl formamide; stirring is carried out for 0.5-12 h; reaction temperature is controlled to 80-250 DEG C, and reaction time is 12-120 h; and by a hydrothermal synthesis method, the metal-organic framework porous adsorption material is prepared. The material has characteristics as follows: specific surface area is large; pore structure height is ordered; pore size is controllable; surface potential energy is controllable; and adsorption capacity of normal paraffin is large. The material can selectively adsorb normal paraffin from mixed materials of normal paraffin and isoparaffin, has high selectivity and has a wide practical application prospect in normal paraffin and isoparaffin separation.

The invention relates to a blocking remover of a gas well shaft. The blocking remover comprises, by weight, 5-25% of an alcohol ether compound, 0.5-10% of a dispersant, 1-10% of a cleaning agent, and 0.5-5% of chelating agent, with the balance being a nitrogen-containing polar solvent, wherein the nitrogen-containing polar solvent is one selected from N,N dimethyl formamide, N,N dimethyl acetamide, and N-methyl pyrrolidone, the alcohol ether compound is one selected from glycol-ether, glycol-propyl ether, glycol-butyl ether, and diglycol-ether, the disperant whose micelle particle size is from 20nm to 100nm is a middle-phase microemulsion-type dispersant mixed by kerosene, water, a surfactant and a cosurfactant, the cleaning agent is one selected from allene diamine, acetonitrile and pentylamine, and the chelating agent is one selected from sodium citrate and EDTA. The blocking remover has the advantages that corrosivity is weak, that the speed of dissolving blockage is fast, that the product performance is stable in high temperatures, and that the blocking remover can reduce damages caused by water locking and fouling in areas close to gas wells, and can recover the permeability of storing layers.