44results about How to "Avoid hydrolysis" patented technology

The invention discloses a catechol side group-containing polylysine derivative as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) dissolving catechol acid in an organic phase, firstly adding NHS, stirring and dissolving until the materials are uniformly mixed, then adding EDC.HCl, and stirring and reacting to obtain a catechol-NHS intermediate solution; (2) dissolving polylysine or a salt thereof in a water phase, and adjusting the pH value to 6.0-7.0 by using an alkaline solution to obtain a solution of polylysine or a salt thereof; and (3) adding the intermediate solution obtained in the step (1) into the polylysine or the salt solution thereof obtained in the step (2), and maintaining the pH value of the reaction system at 5.0-6.0 by using an alkaline solution to obtain the catechol side group-containing polylysine derivative. The preparation method is short in reaction time and mild in reaction condition, and the obtained product is high in grafting rate and high in raw material conversion rate and has a good application prospect in the aspects of tissue adhesives and the like.

This invention belongs to the technical field of lithium battery anode materials, specifically relating to a highly conductive graphite electrode material and its preparation method. The preparation method includes: pre-dissolving sodium carboxymethyl cellulose into a gel solution, then ball-milling and mixing graphite and conductive carbon black, dispersing them together with a cobalt hexacyanorubium(II)-dodecyltungstencobalt(III) salt hybrid material and hafnium diboride nanomaterials in the gel solution, adjusting the acidity, adding styrene-butadiene rubber emulsion to obtain a uniform slurry, and then coating, drying, and compacting to obtain the anode sheet. This invention significantly improves the conductivity and structural stability of the graphite anode through the synergistic effect of the interface modification of the cobalt hexacyanorubium(II)-dodecyltungstencobalt(III) salt hybrid material and the conductive framework of the hafnium diboride nanomaterials. The process is safe and controllable, and suitable for industrial production of lithium-ion batteries.

The invention relates to high-solid-content AlN ceramic slurry for tape casting, a substrate and a preparation method of the substrate, and belongs to the field of ceramic substrates. The ceramic slurry is prepared from the following components in percentage by mass: 60 to 68 weight percent of high-purity AlN powder, 3 to 6 weight percent of dispersing agent, 3 to 5 weight percent of binding agent, 4 to 6 weight percent of plasticizer, 3 to 6 weight percent of sintering aid and 32 to 45 weight percent of solvent, the mass ratio of the plasticizer to the binder ranges from 3: 5 to 4: 5. By regulating and controlling the proportion of the dispersing agent in the AlN ceramic slurry and the solid content of the high-purity AlN powder, the slurry has excellent flowability, dispersity and stability while maintaining high solid content, and is suitable for a tape casting process. The AlN ceramic substrate prepared through sintering is high in density and excellent in heat conductivity, and engineering application can be achieved.

This invention discloses a process for recovering germanium from germanium-silicon alloy waste, belonging to the field of germanium recovery technology. The process includes the following steps: S1. Oxidizing and roasting the germanium-silicon alloy waste to obtain roasted clinker; S2. Sulfidating and fixing the roasted clinker and pyrite to obtain activated clinker; S3. Leaching the activated clinker with sulfuric acid, followed by solid-liquid separation, and collecting the germanium-containing leachate; S4. Performing multi-stage countercurrent extraction on the germanium-containing leachate using an amine extractant to obtain a loaded organic phase; then back-extracting the loaded organic phase with an alkaline back-extraction solution to obtain a germanate solution; S5. Hydrolyzing and precipitating the germanate solution to obtain pure germanium dioxide. The roasting process of this invention fixes impurities and activates elemental germanium into soluble germanium dioxide. The purification stage efficiently separates germanium from other impurity ions, and the final hydrolysis precipitation controls product consistency. This invention's recovery process has high recovery efficiency and purity, is more environmentally friendly, and is expected to achieve large-scale production.

The application belongs to the technical field of sodium-ion battery cathode materials, and discloses a pyrophosphoric acid sodium iron phosphate composite material and a preparation method and application thereof. By regulating the microenvironment of chelation reaction, the chelation state of iron ions is optimized, iron ion precipitation is avoided, and the formation of electrochemically inert impurities is inhibited. Meanwhile, graphene oxide constructs a three-dimensional conductive network to improve the electronic transmission capacity of the material. The pyrophosphoric acid sodium iron phosphate composite material prepared by the application has small particle size, uniform dispersion, no inert impurities and is tightly coated by the conductive network. The material has a discharge specific capacity of 120.9 mAh·g ‑1 at 0.5 C, still maintains a reversible capacity of 78.1 mAh·g ‑1 at 20 C high rate, and has a capacity retention rate of 84.9% after 1000 cycles, and the full battery assembled with the hard carbon negative electrode also exhibits excellent rate and cycle performance.

This invention relates to the field of organic compound preparation technology, specifically a method for preparing 11-triglycerides of carbonate via low-temperature acylation. This method uses glycerol and undecanoyl chloride as raw materials, employing a synergistic system of a "composite acid-binding agent + Lewis acid catalyst," and combines in-situ dehydration technology and a stepwise heating strategy in a dual-solvent environment to achieve efficient synthesis. The specific steps include: under nitrogen protection, dissolving glycerol in a dichloromethane-toluene dual solvent, adding a composite acid-binding agent of pyridine and N,N-diisopropylethylamine, anhydrous zinc chloride catalyst, and 4A molecular sieve for in-situ dehydration; dropwise adding undecanoyl chloride at a low temperature of 5-10°C, followed by sequential heating to 30°C for 2-3 hours and then reacting at 50°C for 12-16 hours; and post-processing using a combined process of filtration-multi-stage extraction-membrane separation-column chromatography. This invention provides mild reaction conditions, effectively suppresses side reactions, produces high-purity products, increases molar yield, and reduces solvent toxicity and purification costs.

This invention belongs to the field of metal rust prevention technology, specifically relating to an environmentally friendly water-based rust-preventive composition, its preparation method, and its application. The composition comprises, by weight, 3-8 parts of a first triazine compound, 1-5 parts of a second triazine compound, 10-20 parts of 2-amino-2-methyl-1,3-propanediol, 2-5 parts of dipropylene glycol monomethyl ether, and 65-85 parts of water. The first triazine compound is a triazine compound having substituents containing hydrophobic segments and at least two aminocarboxylic acid substituents, and the second triazine compound is a triazine compound having thiol substituents. This invention forms a dual-anchored protective film on the metal surface through the two triazine compounds, exhibiting excellent salt spray resistance, damp heat resistance, and film density. It achieves a salt spray test duration of 72 hours, a damp heat test duration of 960 hours, and an adhesion rating of 0. Furthermore, it is free of nitrites, phosphates, and heavy metals. The preparation method is simple, suitable for industrial production, and can be widely applied to metal rust prevention in machinery manufacturing, automotive parts, and other fields.

The application discloses a traditional Chinese medicine composition set for treating lung diseases and a preparation method thereof. The traditional Chinese medicine composition set is composed of one to six independently packaged prescriptions, wherein the one to five prescriptions are oral dosage forms, and are respectively directed to cold cough and asthma, hot and real cough and asthma, virtual cough and asthma, lung cancer specificity and cancer advanced stage for systematic intervention; the sixth prescription is a plaster external application dosage form, and realizes internal and external combined treatment. The medicine liquid is uniformly and equally divided and stored by low-temperature freezing after being pressure-cooked for 20 minutes in a full-closed and zero-gas emission state by using an electric pressure cooker, and is taken by water separation and hot water. Clinical application shows that the application greatly improves the systematic treatment effect on complex lung diseases such as tuberculosis, tumors, lung cancer cough and asthma by the mode of six prescriptions cooperation and dynamic syndrome differentiation and treatment. The accurate closed decoction process perfectly retains volatile oil and weak stability alkaloids in the compound prescription, and effectively improves the stability and repeatability of the batch effect.

The invention discloses a preparation method of an efficient light-emitting silver-indium-sulfur and silver-indium-zinc-sulfur composite nano material, and belongs to the technical field of light-emitting nano materials and preparation. The preparation method comprises the following steps: by taking silver dibutyl dithiocarbamate, indium dibutyl dithiocarbamate and zinc carboxylate as precursors, uniformly mixing at a dodecane neutralization pretreatment temperature to form a mixed solution A; naturally cooling, adding dodecanethiol, and uniformly stirring and mixing to obtain a mixed solution B; at the reaction temperature, decomposing part of silver dibutyldithiocarbamate in the mixed solution B to generate silver sulfide clusters; the activity of the silver sulfide cluster is closely related to the size, the silver sulfide cluster is used as a seed to induce growth of silver-indium-zinc-sulfur, meanwhile, silver sulfide is converted into silver-indium-sulfur, finally, the silver-indium-sulfur and silver-indium-zinc-sulfur composite nano material is obtained, the band gap is 2.0-2.8 eV, the luminous efficiency is 52% or above, and the luminous efficiency can still be kept at 78% or above after five months. The preparation process disclosed by the invention is low in raw material cost and good in process controllability.

The application provides a preparation method of a photo-acid generator sulfonate for ARF photoresist, and belongs to the technical field of organic synthesis. The application uses 2-bromo-2,2-difluoroacetate as a reaction raw material, and is low in cost. The application improves an existing sulfinylation process, specifically, the application uses triphenylmethyl mercaptan as a raw material to introduce a-S- group, and through subsequent hydrogen peroxide oxidation, a sulfonate with high stability is obtained, and the reaction is easy to monitor. Moreover, the application introduces the-S- group first and then introduces an ester group, and in the subsequent deprotection and acylation reaction, heating in an alkaline environment is not needed, and the hydrolysis reaction of the ester group can be avoided.

The invention provides a Tl-series superconducting thin film and a preparation method thereof, and belongs to the field of superconducting thin film materials. The preparation method of the Tl-series superconducting thin film provided by the invention comprises the following steps: mixing nitrate or acetate of metal, ethylenediaminetetraacetic acid, a water-soluble high-molecular polymer and water to obtain precursor sol; the metals are thallium, barium, calcium and copper; the molar ratio of thallium to barium to calcium to copper to ethylenediamine tetraacetic acid is (2-3): 2: 1: 2: (7-8); coating a substrate with the precursor sol to obtain a precursor film; and carrying out heat treatment on the precursor thin film in an oxygen atmosphere under a closed condition to obtain the Tl-series superconducting thin film. The Tl-series superconducting thin film obtained by the preparation method provided by the invention presents a Tl-2212 phase, no impurity phase is generated, and the critical transition temperature can reach 100K and is close to the Tl-2212 theoretical superconducting transition temperature.

This invention relates to the field of daily chemical product technology, specifically to an anti-wrinkle and firming composition, its preparation method, and its application. By weight, the anti-wrinkle and firming composition comprises the following components: 0.01-2 parts of snow lotus extract, 0.1-29.94 parts of Astragalus membranaceus root extract, 0.01-4.5 parts of lime peel extract, 0.1-3 parts of ginseng extract, 0.01-1 part of type heptadecanol, 0.1-10.5 parts of pro-Xylane, 0.4-2 parts of 1,2-pentanediol, 0.4-2 parts of 1,2-hexanediol, and 49.06-99.67 parts of deionized water. By optimizing the preparation process of each raw material in the composition, products containing this composition exhibit significantly improved anti-wrinkle and firming effects. The process is simple, suitable for large-scale industrial production, and meets consumers' demands for safe and effective skincare. This contributes to the transformation of the cosmetics industry towards plant-based raw materials and multi-target intervention for precise anti-aging.

This invention proposes an industrial preparation method for a highly stable, low-impurity ferrous sulfate solution. Targeting 98% high-purity raw materials, it pioneers a fixed mass-to-volume ratio, combined with constant-temperature dissolution at 50-60℃ and sealed protection. Through a four-dimensional linkage of "raw material purity - ratio - temperature - anti-oxidation," the final Fe solution achieves optimal stability. 2+ The concentration is stabilized at 5.2%–6.5%, with a concentration deviation of ≤±0.1%. Simultaneously, a triple logic of "raw material impurity content detection + theoretical calculation + pH closed-loop control" is employed, adapting to the strong neutralizing characteristics of 32% high-concentration liquid alkali, precisely controlling the pH at 4.0–5.0, achieving an impurity removal rate ≥93%, and ensuring that the finished product contains Al <10ppm, Ti <8ppm, and Fe <10ppm. 2+ Retention rate ≥98.5%; filtration efficiency is increased by more than 5 times through a dual-stage high-pressure filtration system (0.7MPa).

The application discloses a kind of preparation methods of anti-oxidation nano silicon slurry, comprising the following steps: (1) oxidation inhibitor is added in alcohol solvent, stirring dissolves;(2) the silicon powder of D50 5-10um is dispersed in above-mentioned solution, and stirring is matched into the silicon slurry of solid content 10%-20%;(3) silicon slurry is ground by sand mill wet, and grinding is carried out in two stages, first using coarse grinding sand mill grinding 2-4h, then switching fine grinding sand mill grinding 15-30h.The application is by adding organic weak acid as oxidation inhibitor in sand mill solvent, so that the oxidation phenomenon of prepared nano silicon slurry is reduced.In addition, the addition of organic weak acid also helps to improve the dispersion performance of slurry, improve the fluidity of slurry, improve sand mill efficiency, and thus greatly improve the electrochemical performance of prepared silicon powder.

This invention belongs to the field of organic synthesis technology and discloses a method for preparing trans-3-chloro-2-propenylhydroxylamine hydrochloride. The method involves adding trans-1,3-dichloropropene to a ketoxime, a base, a phase transfer catalyst, and a first solvent for etherification. After the reaction, the mixture is first extracted with an extractant, and the resulting oil phase is then distilled to obtain the oxime ether. The oxime ether, an aqueous hydrochloric acid solution, and a second solvent are mixed and subjected to vacuum distillation in a distillation column to obtain trans-3-chloro-2-propenylhydroxylamine hydrochloride. This invention avoids the use of an aqueous base in the etherification stage, effectively preventing the hydrolysis of the ketoxime. The purified oxime ether obtained in the etherification step is purified by distillation, significantly reducing side reactions during the subsequent hydrolysis. Adding a solvent during the hydrolysis stage allows for better mixing of the aqueous hydrochloric acid solution and the oxime ether, resulting in more uniform acidification, a more complete reaction, and improved conversion and selectivity.

The utility model relates to a kind of cooling device of sand mill, belong to sand mill cooling technical field, this kind of cooling device of sand mill, including liquid nitrogen storage tank, one side of the liquid nitrogen storage tank is fixedly connected with low-temperature infusion pipeline, one end of the low-temperature infusion pipeline is provided with cooling bin, the inside of the cooling bin is provided with grinding bin low-temperature infusion pipeline is provided with low-temperature liquid nitrogen pump, one side of the grinding bin is fixedly connected with feeding bin, the top of the feeding bin is fixedly connected with feed inlet, one side of the grinding bin is fixedly connected with discharge bin, liquid nitrogen is rapidly transported to cooling bin, the boiling point of liquid nitrogen extremely low can quickly absorb a large amount of heat, can make the temperature of grinding bin located in cooling bin rapidly drop to ultra-low temperature, the flow guide strip specially arranged in cooling bin, liquid nitrogen can be guided to contact with grinding bin uniformly and efficiently, ensure the uniformity and stability of cooling effect.

The application relates to the technical field of plant beverage processing, and discloses a compound star anise liquor and fructooligosaccharide beverage and a preparation process thereof, which is prepared from 11.8wt%-19.6wt% of star anise liquor extract, 8wt%-15wt% of fructooligosaccharide, 0.1wt%-0.3wt% of anhydrous citric acid, potassium sorbate, sodium ascorbate and purified water; the process comprises the following steps: preparing high-concentration fructooligosaccharide syrup by using part of the purified water, adding the extract and sodium ascorbate into the fructooligosaccharide syrup to obtain a high-viscosity complex mother liquor, sterilizing and rapidly cooling the mother liquor under near-neutral conditions, preparing a deep quenching liquid by mixing the remaining purified water, anhydrous citric acid and potassium sorbate, and synchronously colliding and mixing the cooled mother liquor and the deep quenching liquid to carry out sterile filling. The application improves the dispersion state of the hydrophobic components by using a local high-concentration polysaccharide environment, decouples the heating sterilization process and the acid adjusting process, effectively inhibits polysaccharide hydrolysis and essential oil coalescence, and improves the physical and chemical stability of the finished product.

The application discloses a lithium hexafluorophosphate processing device and method, and belongs to the field of lithium battery material production equipment. The device comprises a negative pressure distillation cabin, a nitrogen tank, a liquid nitrogen cabin, a vacuum pump, a gas-liquid separator tank, a waste gas treatment assembly, a compression pump and a material recovery cabin. Nitrogen and liquid nitrogen are mixed to control temperature to-20 DEG C to-30 DEG C, and are input into the negative pressure distillation cabin to realize low-temperature cooling. The negative pressure distillation cabin is divided into upper and lower cabins, and is internally provided with a spraying pipe, a spraying head and a differential pressure backflow valve. When the vacuum pump works, the valve is closed to guarantee distillation. When the vacuum pump stops, the valve is opened to make the material automatically backflow and circulate. After gas-liquid separation, nitrogen is recycled and utilized through compression. The material recovery cabin is internally provided with a hollow shape-changing part. Negative pressure expansion assists crystallization, normal-pressure resetting facilitates unloading. The application is precise in temperature control, high in distillation efficiency, recyclable in nitrogen, non-sticky in crystallization, completely sealed in the whole process, free of water and oxygen, significantly improves the purity and yield of lithium hexafluorophosphate, reduces production cost and is suitable for industrialized production.

The invention relates to the technical field of separation, and relates to chelate resin for removing calcium and magnesium ions in water as well as a preparation method and application of the chelate resin. The chelate resin for removing calcium and magnesium ions in water provided by the invention is composed of the matrix resin and the modified group, and the introduction of the modified group improves the adsorption capacity and stability of the matrix resin to the calcium and magnesium ions, and can respectively reduce the concentrations of calcium ions and magnesium ions in high-salt sewage to 0.5 ppm or below. And the capacity is still kept at 85% or above after 15 times of recycling, so that the sewage treatment cost is greatly reduced, and the method has a wide application prospect.

The invention relates to an anti-impact hinge joint repairing epoxy structural adhesive and a preparation method thereof, and belongs to the technical field of structural adhesives. According to the structural adhesive disclosed by the invention, polysiloxane epoxy resin and silane polyimide are introduced into a basic formula, so that a dual-crosslinking structure is formed, the mechanical strength and toughness of the structural adhesive are enhanced, meanwhile, a preparation method of silane polyimide is optimized, and the stability of substances is improved; besides, organic montmorillonite and silanized carbon nanotubes are added as fillers, a line-plane structure arrangement form is formed in a system, the orientation of the carbon nanotubes can be effectively changed to achieve a dispersion effect, the toughness and strength are greatly improved, and the structural adhesive has excellent impact resistance and no sagging phenomenon, and meets the requirements of plate girder bridge hinge joint repair.

The application relates to the technical field of heat-preservation elbow pipe fittings, and discloses a processing device and method of a heat-preservation elbow pipe fitting, which comprises a template, the template comprises an upper template and a lower template used for butt joint fixing on the peripheral side of a steel elbow, a lower mold injection hole is arranged on the lower template, an upper mold exhaust hole is arranged on the upper template to form a heat-preservation layer, adjusting bolts are arranged at the middle positions of the two sides of the lower template, the adjusting bolts penetrate through the lower template to ensure that the steel elbow is concentric with the lower template; there is no wood support or other materials between the working steel elbow and the forming die, the overall integrity of the heat-preservation layer is guaranteed, and the heat-preservation effect and the overall strength of the heat-preservation layer are improved. Secondly, since the heat-preservation protective layer is wound after the heat-preservation layer is formed, defects existing in the heat-preservation layer can be found in time and repaired, and the possibility that the heat-preservation effect of the heat-preservation layer at local positions is poor can be avoided.

This invention relates to the field of petroleum extraction technology, and discloses a compound, a polymer with oil displacement function, its preparation method, and its application. The compound of this invention has the structure shown in formula (8); the polymer of this invention has good solubility at 20-95℃ and a salinity of 500-50000 mg / L, exhibits good viscosity-enhancing effect on the aqueous phase at high temperatures, can improve the mobility ratio, effectively expand the swept volume, and has good temperature resistance. Simultaneously, it can emulsify and disperse crude oil, reduce interfacial tension, and can be used for polymer flooding to improve oil recovery in conventional reservoirs, high-temperature and high-salinity reservoirs, and ordinary heavy oil reservoirs.

The application discloses a kind of fiber reinforced polylactic acid composite material and its preparation method and application, it is related to fiber material technical field.The composite material is made of polylactic acid matrix 50-90 parts, polymer fiber 5-40 parts, plasticizer 1-10 parts, coupling agent 0.5-5 parts, stabilizer 0.5-5 parts are composed, wherein stabilizer is realized molecular level anti-aging protection by deuterium group and heterocyclic structure, and polymer fiber is treated by alkali solution and enhanced interface bonding.The material has excellent toughness and weather resistance, and can be widely used in biodegradable medical implant devices, high weather resistance packaging materials and environmental protection daily necessities field.

The application belongs to the technical field of adhesive manufacturing, and discloses a long-acting anti-aging high-adhesion-strength elastic hybrid adhesive, a preparation method and application thereof. The preparation method comprises the following steps: preparing a long-acting A component with weak acidity and high storage stability, and preparing a long-acting B component with high storage stability; through synchronous improvement of the adhesive formula and process, a ternary hybrid system is adopted, and the problems of compatibility of the ternary system and hydrolysis of the MS catalyst are overcome, so that the prepared A and B components can be stored stably for a long time, the adhesive can have high strength, high elasticity, high storage stability and low cost at the same time, the adhesive is convenient to produce and can be stored stably for a long time, and the adhesive can be widely applied to the manufacturing of power battery cells and other products and can meet various actual application requirements of the industry.

The utility model discloses a mobile sample protection, isolation and transfer device, the mobile sample protection, isolation and transfer device comprises a base, a main body and an air inlet structure, the main body is fixedly installed at the top end of the base, a plurality of limiting plates and transverse plates are arranged in the main body, and the air inlet structure is arranged in the main body. The interior of the main body is divided into a plurality of accommodating cavities by limiting plates and transverse plates, the accommodating cavities are used for placing samples to be transferred, the air inlet structure is arranged at the bottom of the rear side of the main body, and a sealing door is arranged on one side of the main body and is used for completely sealing the main body. According to the utility model, the occurrence of secondary exposure of the sample in the transfer or storage process is effectively avoided, the safety of operators and the environment is guaranteed, the influence of environmental factors such as a light source, temperature and humidity on the properties of the sample is reduced, and the flux of single transfer can be improved.

The present application relates to a kind of pyraclostrobin chlorothalonil water emulsion and its preparation method, it relates to the technical field of pesticide preparation, wherein, by mass percentage, the water emulsion includes pyraclostrobin 8-12%, chlorothalonil 16-24%, solvent 10-18%, composite surfactant 8-15%, photosynthesis promoter 2-6%, penetration spreader 3-8%, epichlorohydrin 1-3%, glycerol 3-6%, organic silicon defoaming agent 0.1-0.5%, the rest is water;The mass ratio of pyraclostrobin and chlorothalonil is 1:2.The present application realizes the rapid penetration of liquid medicine and the rapid dry of disease spot by accurate particle size control and formula system, simultaneously significantly enhances the photosynthesis of crops using photosynthesis promoter, realizes the dual effect of spot control and leaf, quality increase and yield increase while high-efficiency sterilization.

The application provides a vacuum drying method of a sodium ion battery cell, and belongs to the technical field of sodium ion battery manufacturing; the technical problem to be solved is that existing sodium ion battery pole pieces are prone to water absorption, and electrolyte is prone to hydrolysis; the technical solution for solving the technical problem is that: step 1: pretreating the cell; step 2: placing the cell into an oven, starting a vacuum system and a heating system in the oven; step 3.1: preheating the oven; step 3.2: starting an inert gas supply system, introducing inert gas into the oven for pulse purging, and controlling the heating system to perform vacuum pulse baking, the purging period of pulse purging is consistent with the baking period of vacuum pulse baking; step 4: turning off the heating system, and taking out the cell after the temperature in the oven is naturally cooled; wherein, one baking period comprises a temperature rising stage, a constant temperature stage and a temperature falling stage; the application is applied to the production of sodium ion battery energy storage and power batteries.

The application discloses a kind of high-strength polylactic acid melt-spun fibers prepared by low-temperature cold drawing.The preparation method comprises the following steps: (1) drying, polylactic acid chip is placed in oven for drying; (2) melt extrusion, polylactic acid chip after drying is put into screw extruder for heating and extrusion; (3) drawing, extruded polylactic acid melt is introduced to drawing roller, and the fiber is thinned by rotating speed; (4) collection, polylactic acid fiber is introduced to collection roller for winding.The application dries polylactic acid chip before use to remove moisture, avoiding hydrolysis in melt processing; spinning is carried out at a lower spinning temperature, ensuring the flowability of polylactic acid while avoiding the probability of high-temperature thermal degradation; drawing is carried out at room temperature, and polylactic acid fiber is oriented and induced to crystallize.The polylactic acid fiber obtained by the method has good mechanical properties.

The invention belongs to the technical field of self-assembled microsphere arrays, and particularly relates to a pore-adjustable and stable self-assembled microsphere array as well as a preparation method and application thereof. The microsphere array disclosed by the invention is self-assembled in a manner of combining electrostatic mediation and covalent coupling, and contact among the microspheres is guided by virtue of electrostatic interaction, so that guidance is provided for realizing controllable covalent coupling among the microspheres by virtue of Schiff base reaction. The combination of covalent coupling and electrostatic force can improve the flexibility of the microsphere array and the stability of the combination between the microspheres, so as to improve the stability of pores between the microspheres, reduce the collapse of the microsphere array, provide a good and controllable three-dimensional space for the creeping growth of cells, and facilitate the promotion of wound healing and growth. The self-assembled microsphere array is suitable for application modes such as smearing or injection, and the scene applicability is greatly improved.

The application discloses a preparation method of 3-chloro-5-fluoro-2-methylbenzoic acid, relates to the technical field of 3-chloro-5-fluoro-2-methylbenzoic acid production, and the method is characterized in that: 2-methyl-5-nitrobenzoic acid is used as a starting raw material, selective chlorination is carried out on the starting raw material in preheated high-temperature concentrated sulfuric acid and dichloro hydantoin, then esterification is completed by a one-pot method, catalytic hydrogenation reduction is carried out under low-pressure and low-temperature conditions by the synergistic action of a Raney nickel catalyst and a platinum-carbon catalyst, a high-purity amino intermediate is obtained, smooth thermal decomposition fluorination is carried out in a diglycol dimethyl ether solvent, alkaline hydrolysis and refinement are carried out, and finally the end product is obtained; the product has high purity and high yield.