88 results about "Tetramethylethylenediamine" patented technology

The invention discloses a self-adaptive hydrogel coupling agent as well as a preparation method and application thereof, belongs to the field of medical instruments, and particularly relates to a preparation method of the self-adaptive hydrogel coupling agent. The preparation method comprises the following steps: dissolving a main monomer, a functional monomer, a molecular weight regulator and a reinforcing filler in sterilized deionized water under dark and sterile conditions, carrying out a free radical polymerization reaction under the action of a persulfate solution and tetramethylethylenediamine, and carrying out dialysis and sterilization treatment to obtain the self-adaptive hydrogel coupling agent. The self-adaptive hydrogel coupling agent prepared by the invention eliminates tissue deformation caused by probe pressurization, significantly improves the accuracy of measurement of the actual distance of a target by ultrasound in an operation, and meanwhile, the self-adaptive hydrogel coupling agent is good in biocompatibility, can be sterile, is convenient to operate, and is suitable for open or endoscopic surgical wounds.

The invention relates to the technical field of gel material preparation, in particular to a bio-based gel material for dangerous chemical leakage disposal and a preparation method thereof.The preparation method comprises the steps that gelatin and deionized water are added into a reaction container, a gelatin solution is obtained under the preset dissolution condition, alkaline protease is added into the gelatin solution for an enzymolysis reaction, and a gelatin solution is obtained; a modified gelatin solution is obtained; the preparation method comprises the following steps: adding a phytic acid-chitosan compound and magnesium-aluminum layered double hydroxide into dispersion equipment, and obtaining a composite inorganic matter dispersion liquid under a preset dispersion condition; adding the modified gelatin solution, the composite inorganic substance dispersion liquid, polyethylene glycol and phase change microcapsules into a mixing reactor, and obtaining a premixed solution under a preset mixing condition; sequentially adding an initiator, a cross-linking agent and tetramethylethylenediamine into the premixed liquid, and performing cross-linking reaction under preset cross-linking conditions to obtain a bio-based gel initial product. The plugging efficiency of the bio-based gel material on dangerous chemical leakage is improved.

The invention relates to the technical field of oilfield chemistry, in particular to a clay stabilizer containing dihydroxyl quaternary ammonium salt and a preparation method thereof, and the preparation method of the clay stabilizer containing dihydroxyl quaternary ammonium salt comprises the following steps: mixing required amounts of tetramethylethylenediamine, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride and a hydrogen bond donor for reaction to obtain the clay stabilizer containing dihydroxyl quaternary ammonium salt. And after the reaction is ended, obtaining the clay stabilizer containing the dihydroxyl quaternary ammonium salt. The clay stabilizer containing dihydroxyl quaternary ammonium salt is high in charge density and remarkable in clay expansion prevention effect; the fabric has the characteristic of multi-point adsorption and is high in washing resistance; the polymer is composed of small molecular weight compounds and can be used for transformation of low-permeability and ultra-low-permeability reservoirs. And meanwhile, the fracturing fluid has good compatibility with the fracturing fluid, the influence on the viscosity of the fracturing fluid is small, and the sand-carrying performance of the fracturing fluid can be guaranteed while reservoir protection is realized. The preparation method of the clay stabilizer containing the dihydroxyl quaternary ammonium salt is simple in process, easy to control and implement and suitable for industrial large-scale production.

The invention belongs to the technical field of underground engineering grouting materials, and discloses an anti-dispersion solid waste grouting filling material and a preparation method and application thereof. The slurry A is prepared from the following components in parts by mass: 400 to 1000 parts of fly ash, 500 to 1000 parts of blast furnace slag, 100 to 500 parts of Portland cement, 250 to 1200 parts of water, 5 to 50 parts of sodium hydroxide and 10 to 50 parts of PolyFure-I; the polyFure-I comprises acrylamide and N, N, N ', N'-tetramethylethylenediamine, and the polyFure-I comprises acrylamide and N, N, N ', N'-tetramethylethylenediamine; the slurry B is prepared from the following components in parts by mass: water glass and PolyFure-II; the PolyFure-II is prepared from water glass, an ammonium persulfate solution, xanthan gum and carboxymethyl cellulose. The flowing water dispersion resistance of the grouting material is effectively improved, the blocking effect of flowing water is enhanced, and the problem of insufficient blocking of a traditional grouting material is solved.

This invention relates to a method for preparing a broadband absorption hydrogel. The method comprises the following steps: S1, mixing solvent A (N,N-dimethylformamide or acetonitrile) with deionized water to obtain a mixed solvent; S2, adding polyethylene glycol methyl ether acrylate-480 and acryloylmorpholine to the solvent in S1 and dissolving them to obtain a mixed solution; S3, removing dissolved oxygen from the mixed solution in S2, sealing the container, and stirring under ice bath conditions; S4, adding potassium persulfate and N,N,N',N'-tetramethylethylenediamine to the mixed solution after stirring in S3, and sealing the container again; S5, completing the polymerization reaction in the container at 60 °C to obtain the hydrogel. Compared with the prior art, the hydrogel material provided by this invention has improved reflection loss intensity and effective absorption bandwidth performance, thus providing a new perspective for developing highly flexible and efficient electromagnetic wave absorbers.

The invention relates to polyvinyl alcohol polynitrogen isoacrylamide cellulose hydrogel with an anisotropic structure as well as a preparation method and application of the polyvinyl alcohol polynitrogen isoacrylamide cellulose hydrogel, and belongs to the technical field of water catching materials. The preparation method of the hydrogel comprises the following steps: S1, adding polyvinyl alcohol, glutaraldehyde and lithium chloride into deionized water to obtain a mixed solution A; s2, adding the cellulose nanocrystal powder into deionized water to obtain a cellulose nanocrystal dispersion liquid; s3, adding N-isoacrylamide and N, N-methylene bisacrylamide into deionized water, so as to obtain a mixed solution B; s4, adding the mixed solution A and the cellulose nanocrystal dispersion solution into the mixed solution B, and reacting to obtain a mixed solution C; s5, ammonium persulfate, hydrochloric acid and tetramethylethylenediamine are added into the mixed solution C, freezing, low-temperature crosslinking and unfreezing are conducted, and then freezing-unfreezing circulation crosslinking is conducted; and finally, taking out, unfreezing and dialyzing. The hydrogel provided by the invention has a highly anisotropic structure and regular vertical pore channels.

This invention relates to the field of organic synthesis technology, specifically to a highly efficient and stable Grignard preparation and its green preparation method. By weight, it comprises 8-18 parts of a magnesium source, 40-92 parts of a halogenated hydrocarbon, 150-200 parts of a green solvent, 15-20 parts of ethylene glycol dimethyl ether, and 2.3-3.2 parts of a synergistic stabilizer. The green solvent is 2-methyltetrahydrofuran, or a composite solvent with a weight ratio of 2-methyltetrahydrofuran:methyl tert-butyl ether of 150-160:40-50. The synergistic stabilizer is composed of 1.5-2.0 parts of N,N,N',N'-tetramethylethylenediamine and 0.8-1.2 parts of butylated hydroxytoluene, or composed of 1.5-2.0 parts of N,N,N',N'-tetramethylethylenediamine and 1.0 part of phenothiazine. This invention uses a green solvent system to replace traditional toxic and harmful solvents, and combines it with a solvent recovery process to achieve solvent recycling, which greatly reduces waste emissions and makes the production process safer and more environmentally friendly, in line with the development direction of green chemical industry.

The invention relates to a hydrogel with both strength and electromagnetic wave absorption and a preparation method thereof. The preparation method of the hydrogel material comprises the following steps: S1, carrying out amination treatment on Fe3O4; s2, adding Fe3O4-NH2 and GO in the step S1 into deionized water, and carrying out ultrasonic dispersion; s3, adding polyethylene glycol methyl ether acrylate-480 and acryloyl morpholine into the dispersion liquid in the S2, and dissolving the polyethylene glycol methyl ether acrylate-480 and the acryloyl morpholine to obtain a mixed liquid; s4, removing dissolved oxygen in the mixed solution in S3, sealing the container, and stirring under an ice bath condition; s5, adding potassium persulfate and N, N, N ', N'-tetramethylethylenediamine into the mixed solution stirred in the step S4, and closing the container again; s6, the container is subjected to a polymerization reaction at the temperature of 60 DEG C, and hydrogel is obtained. Compared with the prior art, when the thickness of the hydrogel material is 2.07 mm, strong broadband microwave absorption is achieved, RLmin is-57.0 dB, EABmax is 6.4 GHz, meanwhile, excellent flexibility is kept, and the work provides a new view angle for developing a high-flexibility and efficient electromagnetic wave absorber.

The present invention relates to a composition comprising at least one amine selected from the group consisting of N,N,N',N'-tetramethylethylenediamine, N,N,N',N'- tetramethylpropylenediamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, N,N- dimethylethylenediamine, 4-methylmorpholine, dimethyl-(2-azidoethyl)amine and mixtures thereof; at least one organic solvent selected from the group consisting of acetonitrile, dimethyl isosorbide, acetone, dimethylsulfoxide, and mixtures thereof; and at least one carboxylic, nitrate, or sulfate salt of a transition metal; wherein the transition metal is completely dissolved in the composition. The invention also relates to hypergolic compositions and uses thereof.

The application provides a fluorine-substituted graphdiyne-protected zinc ion secondary battery zinc negative electrode and a preparation method and application thereof. The preparation method comprises the following steps: (1) preparing a reaction solution, wherein the reaction solution comprises 1,3,5-trifluoro-2,4,6-tri-alkynyl benzene, cuprous iodide, pyridine, tetrahydrofuran and N,N,N',N'-tetramethyl ethylenediamine; and (2) taking a zinc foil as a substrate, and preparing the fluorine-substituted graphdiyne-protected zinc ion secondary battery zinc negative electrode in situ on the surface of the zinc foil through a cross-coupling reaction of 1,3,5-trifluoro-2,4,6-tri-alkynyl benzene in the reaction solution. According to the preparation method, the fluorine-substituted graphdiyne can be controllably grown on the surface of the zinc foil through an in-situ preparation method, the preparation method has the advantages of mild conditions, simple operation and suitability for large-scale preparation. Moreover, the prepared fluorine-substituted graphdiyne-protected zinc ion secondary battery zinc negative electrode can be used as a new negative electrode material of the zinc ion secondary battery, can inhibit zinc dendrite growth and relieve hydrogen evolution, and can significantly improve the cycle life of the zinc ion secondary battery.

The application belongs to the technical field of adsorbents, and provides a composite adsorbent material for uremia and a preparation method thereof, and the preparation steps are as follows: S1. Acrylamide, N,N'-methylenebisacrylamide, glycerol and deionized water are mixed, stirred, sodium alginate is added, stirred and dissolved, ammonium persulfate, calcium sulfate and tetramethylethylenediamine are sequentially added, stirred, ultrasonically treated, and heated and reacted to obtain a sodium alginate derivative; S2. The sodium alginate derivative and deionized water are mixed, modified high-density polyethylene is added, stirred, and soaked in a CaCl2 solution for crosslinking to obtain a sodium alginate composite material; S3. CeO2 / MoS2 functional material, sodium alginate and deionized water are mixed, the sodium alginate composite material is added and stirred, shaped, soaked in a CaCl2 solution for crosslinking, washed, and dried to obtain the composite adsorbent material. The composite adsorbent material has a high adsorption rate and high adsorption capacity for uremia toxins, and has good biocompatibility and hemocompatibility.

The invention relates to a polynitrogen isoacrylamide graphene oxide cellulose hydrogel with an anisotropic structure as well as a preparation method and application of the polynitrogen isoacrylamide graphene oxide cellulose hydrogel, and belongs to the technical field of water treatment. The preparation method of the hydrogel comprises the following steps: S1, adding graphene oxide into deionized water to obtain a graphene oxide dispersion liquid; s2, adding the cellulose nanocrystal powder into deionized water to obtain a cellulose nanocrystal dispersion liquid; s3, nitrogen isoacrylamide and nitrogen nitrogen methylene bisacrylamide are added into deionized water, and a mixed solution is obtained; s4, adding a graphene oxide dispersion liquid and a cellulose nanocrystal dispersion liquid into the mixed liquid, and reacting to obtain a nanocrystal solution; s5, a catalyst and tetramethylethylenediamine are added into the nanocrystalline solution, freezing, low-temperature crosslinking and unfreezing are conducted, and then freezing-unfreezing circulation crosslinking is conducted; and finally, taking out, unfreezing and dialyzing. The hydrogel provided by the invention has excellent solar photo-thermal water evaporation performance.

This invention relates to DNA-functionalized thermosensitive phase transition polymers, their preparation methods, and applications, belonging to the interdisciplinary field of functional polymers and biomaterials. It aims to solve the technical problems of existing exosome separation methods, such as long processing time, low purity, high cost, and inability to specifically separate exosome subtypes. This invention provides a polymer prepared via free radical polymerization using N-isopropylacrylamide and acrylamide-modified DNA as monomers, and ammonium persulfate and tetramethylethylenediamine as initiators. This polymer exhibits reversible phase transition properties at physiological temperatures and is applied to the separation and detection of exosome subtypes. Specific capture and quantitative analysis are achieved through DNA recognition probes and fluorescently labeled antibodies. The polymer of this invention is simple to operate, quick to prepare, low in cost, and high in purity. It requires only a common centrifuge for non-destructive separation of exosomes and can integrate detection functions, providing technical support for diagnosis and detection.

The present application relates to the technical field of biomedical materials, and particularly relates to a 3D-printed self-produced electricity hydrogel scaffold for promoting wound healing and a preparation method and application thereof, comprising an anode scaffold and a cathode scaffold, the anode scaffold is prepared from a zinc-containing hydrogel, and the cathode scaffold is prepared from an iron-containing hydrogel; the anode scaffold further comprises a prepolymerization solution prepared from dopamine, ammonium persulfate, N,N'-methylene bisacrylamide, acrylamide and tetramethylethylenediamine; the hydrogel scaffold can gradually degrade to release metal ions, play an anti-inflammatory and angiogenic role, can remove free radicals such as active oxygen and active nitrogen, and play an antioxidant role; the output voltage can be stabilized for more than 7 days, the expression of repair-related genes can be improved through physiological micro-current stimulation, the proliferation and migration of fibroblasts can be promoted, the wound can be accelerated to realize scarless healing within 16 days, and the hydrogel scaffold has a wide application prospect.

The application discloses a preparation method of an ion-thermal sensitive composite gel for efficiently extracting nicotine. The method comprises the following steps: physically mixing boron nitride (BN) and anhydrous citric acid, ball milling, washing, centrifuging and drying to obtain boron nitride nanosheets. Then, the boron nitride nanosheets and ionic liquid are reacted under a nitrogen atmosphere for 24 h to obtain ionic liquid-boron nitride nanosheets (IL-BNNs). The IL-BNNs are dispersed into a monomer solution, a crosslinking agent is added after the formation of the gel, and then tetramethylethylenediamine and ammonium persulfate are added and stirred in an ice bath. The mixed system is transferred into a mold to react for 12-24 h to obtain the ion-thermal sensitive composite gel. The application forms dense nicotine binding sites in the interior of the composite material by using ionic liquid, so that the adsorption-desorption performance of the material to nicotine is enhanced. Meanwhile, the desorption performance of the material is strengthened by using the thermal conductivity of boron nitride and the phase change characteristics of the gel, so that the nicotine extraction process is simplified, and the amount of eluent in the nicotine recovery process is reduced.

The application discloses a self-adapting hydrogel coupling agent and a preparation method and application thereof, and belongs to the field of medical devices, and particularly relates to a preparation method of a self-adapting hydrogel coupling agent; the preparation method comprises the following steps: under the conditions of light avoidance and sterility, main monomers, functional monomers, a molecular weight regulator and reinforcing fillers are dissolved in sterilized deionized water, and then free radical polymerization is carried out under the action of a persulfate solution and tetramethylethylenediamine, and after dialysis and sterilization treatment, the self-adapting hydrogel coupling agent is obtained. The self-adapting hydrogel coupling agent prepared by the application eliminates tissue deformation caused by probe pressurization, significantly improves the measurement accuracy of an actual distance of a target in an operation by ultrasonic waves, and is good in biocompatibility, can be sterilized, is convenient to operate, and is suitable for open or endoscopic operation wounds.

The invention belongs to the technical field of grouting materials, and particularly relates to an anti-aging hydrogel composite grouting material for water gushing plugging and a preparation method of the anti-aging hydrogel composite grouting material. The composite grouting material comprises the following components in parts by mass: anti-aging hydrogel, and the anti-aging hydrogel is prepared from the following raw materials in parts by mass: 60-80 parts of a poly (N-isopropylacrylamide) solution, 20-40 parts of a sodium acrylate solution, 1 part of ammonium persulfate, 1 part of N, N-dimethylformamide, 1 part of a cross-linking agent, 1 part of a cross-linking agent, 1 part of a cross-linking agent, 1 part of a cross-linking agent, and 1 part of a cross-linking agent. The concrete is prepared from, by weight, 1 part of N, N-methylene bisacrylamide, 0.775 part of tetramethylethylenediamine, 1-3 parts of composite cement, 3 parts of a surface enhancer and 1 part of a water guide agent. The composite cement comprises the following components: sulphoaluminate cement clinker and gypsum. According to the invention, the aging resistance of the hydrogel for water burst plugging can be improved. In addition, the addition of the composite cement also helps to improve the expansion rate of the prepared anti-aging hydrogel, so as to improve the effect of water gushing plugging.

The invention discloses a preparation method and application of a swelling-inhibiting dual-network membrane, and the method comprises the following steps: (1) putting chloromethylated polysulfone and tetramethylethylenediamine into a NaOH solution for pre-crosslinking to obtain a crosslinked chloromethylated polysulfone solution; (2) mixing the cross-linked chloromethylated polysulfone solution with the sulfonated polyetheretherketone solution, stirring at 60-80 DEG C for 2-4 hours, then cooling to 40-50 DEG C at a rate of 5-10 DEG C / h, and stirring at a constant temperature for 8-12 hours to obtain a membrane casting solution; and (3) drying the membrane casting solution to prepare the swelling-inhibiting dual-network membrane. According to the invention, through precise regulation and control of covalent cross-linked network density and directional optimization of a blended microphase structure, synergistic improvement of swelling inhibition, efficient ion conduction, excellent mechanical properties and zinc dendrite resistance is synchronously realized in a strong alkaline environment.

The invention provides a stable and durable wearable sweat and sugar electrochemical sensor. A sensing interface of the sensor is prepared by sequentially dispensing a glucose sensing solution and a film forming solution on the surface of a carbon electrode, the glucose sensing solution comprises a zeolite imidazate framework-90 (ZIF-90 at GOx) composite material loaded with glucose oxidase, Prussian blue nanoparticles (PBNPs) and a conductive gel solution, and the film forming solution comprises ammonium persulfate and tetramethylethylenediamine. Glucose in sweat is oxidized by using ZIF-90 at GOx on a sensing interface, generated hydrogen peroxide reacts with PBNPs to generate a current signal on an electrode, and then quantitative analysis is performed on the glucose in the sweat based on a standard curve method. The wearable sweat and sugar electrochemical sensor provided by the invention has excellent environmental adaptability and durability, can be used outdoors for a long time, is simple to prepare and good in product performance, and has a very good application prospect in the field of development of wearable sweat and sugar sensors.

This invention discloses a methyl β-cyanoethylsiloxane-polyethylene glycol copolymer, its preparation method, and its applications, relating to the fields of polymer materials and electrochemical technology. The preparation method of this copolymer is as follows: tetramethylethylenediamine is reacted with cuprous oxide under an inert atmosphere to obtain a catalyst; methyldichlorosilane and acrylonitrile are dissolved in solvent A, and the catalyst is added to carry out the reaction; polyethylene glycol is added to the reaction solution, and the reaction continues under concentrated sulfuric acid catalysis to obtain a crude product; solvent B is added to the crude product, followed by washing and vacuum drying to obtain the methyl β-cyanoethylsiloxane-polyethylene glycol copolymer. This invention effectively improves the interfacial stability of the electrolyte and the efficiency of interfacial ion transport, thereby enhancing the cycle and rate performance of lithium-ion batteries.

The invention relates to the technical field of soldering flux, and particularly discloses a water-soluble normal-temperature solidification type soldering flux for an aluminum soldering tin wire and a preparation method of the soldering flux. The invention relates to a water-soluble normal-temperature solidification type soldering flux for an aluminum soldering tin wire. The soldering flux comprises the following components in parts by mass: 16-24 parts of polyethylene glycol; 16 to 24 parts of fluoboric acid; 15 to 31 parts of tri-n-octylamine; 14 to 26 parts of tetramethylethylenediamine; 8 to 12 parts of water-soluble zinc salt; 2 to 8 parts of water-soluble stannous salt; 0.4 to 1 part of a surfactant; and 0.6-2 parts of a slow release agent. The water-soluble soldering flux has the advantages that the water-soluble soldering flux which is in a solid state at normal temperature can better improve the welding strength, and the residual color after welding is relatively light.

The application discloses a preparation method of a hydrogen peroxide and zinc ion double-response hydrogel precursor, and the method comprises the following steps: firstly, preparing a Fe-MOF suspension, and then mixing the Fe-MOF suspension with a buffer solution of acrylamide and N,N-methylene bisacrylamide, and a solution containing an oxidant and tetramethylethylenediamine to obtain a hydrogel precursor. Then, the hydrogel precursor is dried to obtain a hydrogel. The application further discloses the use of the hydrogel precursor and the hydrogel. According to the preparation method, the reaction time is short, the preparation method is simple, and the method has certain universality. The prepared hydrogel material has good mechanical properties, a large specific surface area, a three-dimensional network structure, good electrical conductivity, and the property of fast response to changes, and can be used in electrochemical sensors, and has wide application prospects in the fields of biological detection, disease diagnosis, food hygiene and the like.

The invention discloses a preparation method of a toughness and conductivity synergistically enhanced high-performance hydrogel wearable sensor based on hydrophobic association, which comprises the following steps: mixing a gelatin aqueous solution with MXene, and then adding lauryl sodium sulfate, NaCl and octadecyl methacrylate to prepare a micelle solution; adding acrylamide into the micelle solution, stirring and cooling, and then adding ammonium persulfate, N, N '-methylene bisacrylamide and N, N, N', N '-tetramethylethylenediamine; and finally, transferring the solution into a mold, and carrying out gelation reaction at room temperature. Therefore, the high-performance hydrogel with synergistically enhanced toughness and conductivity based on hydrophobic association is obtained. The gelatin / polyacrylamide / MXene hydrogel is obtained by introducing micelles into the hydrogel, utilizing a hydrophobic association method and adopting thermal initiation polymerization, and the gelatin / polyacrylamide / MXene hydrogel has the advantages of simple process, easiness in operation, controllable reaction conditions, high sensing sensitivity and large strain monitoring range, and can be applied to various occasions.

The application relates to the technical field of organic synthesis, in particular to a catalyst for catalytic synthesis of N,N,N',N'-tetramethyl ethylenediamine and a preparation method and application thereof. The copper-nickel-cerium-zirconium catalyst is composed of CuO-NiO-CeO2-ZrO2; wherein the molar ratio of CuO, NiO, CeO2 and ZrO2 is (60-65):(5-25):(10-25):(1-10). The copper-nickel-cerium-zirconium catalyst provided by the application can efficiently catalyze the reaction of dimethylamine and ethylene glycol to prepare N,N,N',N'-tetramethyl ethylenediamine, the conversion rate of ethylene glycol can reach 99%, and the selectivity of N,N,N',N'-tetramethyl ethylenediamine can reach 90%.

The invention discloses a preparation method of high-durability high-modulus modified asphalt. The preparation method comprises the following steps: (1) pre-emulsification: mixing a monomer system with an emulsification system; (2) seed polymerization and core-shell structure construction; and (3) chemical functionalization modification: adding 3-5 parts of epichlorohydrin and 0.1-0.2 part of tetramethylethylenediamine into the product, reacting for 4 hours at 70 + / -1 DEG C under the protection of nitrogen, and controlling the gel content to be less than or equal to 8%. Carboxyl introduced by methacrylic acid and polar groups in asphalt form chemical bonding, epoxy group crosslinking enhances the interface bonding force between latex and asphalt, and the water sensitivity is remarkably reduced; the performance of the latex can be adjusted according to the requirements of different climate zones through particle size grading and reaction parameter regulation and control, and the adaptability is wider.

The invention belongs to the field of biopesticide preparation, and particularly discloses a preparation process of avermectin B2a fine powder. The process comprises the following steps: (1) carrying out vacuum concentration on the abamectin B1a crystallization mother liquor until no fraction exists, so as to obtain paste; adding ethyl acetate into the paste, heating, dissolving and washing to obtain an ethyl acetate dissolving solution; (2) slowly cooling the ethyl acetate solution to-5 DEG C to-15 DEG C, performing primary crystallization, and performing suction filtration to obtain abamectin B2a coarse powder; (3) adding ethyl acetate into the abamectin B2a coarse powder, stirring and dissolving at high temperature, slowly cooling, carrying out secondary crystallization, and carrying out suction filtration to obtain abamectin B2a primary fine powder; and (4) adding ethyl acetate into the primary avermectin B2a fine powder, stirring at high temperature until the primary avermectin B2a fine powder is completely dissolved, adding tetramethylethylenediamine or triethylamine, slowly cooling, carrying out last crystallization, and carrying out suction filtration and drying to obtain the avermectin B2a fine powder. The storage stability of the obtained abamectin B2a is effectively improved while the high purity is maintained.

The invention relates to a diamond thinning grinding wheel based on gel-casting physical foaming molding, which is characterized by being mainly prepared from the following raw materials: powder, water, acrylamide, N, N '-methylene bisacrylamide, a dispersing agent, a surfactant, an initiator and tetramethylethylenediamine, the powder is formed by mixing, by weight, 18%-25% of a ceramic bond and the balance diamond abrasives. 75%-82% of a diamond abrasive; the addition amount of water is 40-60% of the weight of the powder; the sum of the weight of the powder and the water is recorded as slurry. The thinned grinding wheel has high porosity and a regular pore structure, the self-sharpening performance and the chip containing and discharging performance of the grinding wheel can be improved, the grinding performance and the grinding surface performance of the grinding wheel are improved, and the technological process is simple.

The invention relates to an asymmetric adhesion bionic hydrogel dressing and a preparation method thereof. The preparation method is characterized by comprising the following steps: (1) dissolving acrylamide and acrylic acid in water; then adding N, N '-methylene bisacrylamide and N, N, N', N '-tetramethylethylenediamine, then adding FeCl3 and ammonium persulfate, and carrying out crosslinking to obtain upper-layer hydrogel; (2) adding protocatechuic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide into the hydroxypropyl chitosan solution, so as to obtain an adhesive layer; and (3) coating one surface of the upper-layer hydrogel with the adhesion layer, and curing at room temperature to obtain the asymmetric adhesion bionic hydrogel dressing. The asymmetric adhesion bionic hydrogel dressing has the advantages that one surface of the prepared asymmetric adhesion bionic hydrogel dressing has good adhesion performance and is used for being adhered to a wound, and the other surface of the asymmetric adhesion bionic hydrogel dressing is low in adhesion performance; the adhesive composition can be firmly adhered to tissues and can prevent the generation of bad adhesion.

The application provides a cellulose-based nanofiber material and a preparation method and application thereof, and the preparation method is as follows: a cellulose raw material is dissolved in an ionic liquid, an aprotic solvent is added, and an electrospinning solution is obtained; the electrospinning solution comprises, in percentage by mass, 4-6% of cellulose, 10-76% of ionic liquid, 20-84% of aprotic solvent, 0.2-1.5% of soluble ferric salt, 0.4-3% of soluble ferrous salt, and a cellulose polymerization degree of 100-1200; spinning is performed by using the electrospinning solution under ambient humidity of 50-80%, the product is immersed in a NaOH solution, and then cleaned with water to obtain cellulose nanofibers; the cellulose nanofibers are immersed in a mixed solution of N-isopropyl acrylamide, a crosslinking agent and an initiator for 12-24 hours, and then immersed in a tetramethylethylenediamine liquid for 12-24 hours to obtain the cellulose-based nanofiber material. The cellulose-based nanofiber material has high oil-water separation efficiency, good recycling performance, and can realize automatic oil-water separation on demand.