226 results about "Non solvent" patented technology

The invention discloses a mixed matrix membrane for efficient oxygen and nitrogen separation and a preparation method and application thereof. The mixed matrix membrane comprises a polymer continuous phase and an MOF filler uniformly dispersed in the polymer continuous phase, the MOF filler can separate nitrogen and oxygen, and the surface of the MOF filler is modified by the silane coupling agent, so that the MOF filler is well compatible with a polymer, and the oxygen-nitrogen separation effect is improved. The polymer solution and the MOF filler dispersion liquid are mixed, the mixed matrix membrane is prepared through the non-solvent induced phase separation method, and the method has the advantages of being simple in reaction condition, high in efficiency, easy to amplify and the like and has wide engineering prospects.

The present invention discloses a preparation method of a photothermal super-hydrophobic coating with excellent anti-icing / de-icing performance under a low temperature and high relative humidity environment, first by in situ growth of photothermal Cu-MOF nanoparticles on the surface of low thermal conductivity fibrous clay mineral nanoparticles, constructing a two-level nano- / nano-structured composite photothermal particle, which is then subjected to low surface energy modification and introduced into a low thermal conductivity binder, and a binder is induced to phase separate to form a micron-scale binder / low surface energy nanoparticle aggregate by a non-solvent, and finally a photothermal super-hydrophobic coating with a three-level micro- / nano- / nano-structure is constructed by spraying. The three-level micro- / nano- / nano-structure of the coating simultaneously gives the coating excellent photothermal performance and the Cassie-Baxter state stability of the droplet on the coating surface under a low temperature and high relative humidity environment, so that it has excellent passive anti-icing / frosting and active de-icing / defrosting performance in this environment. The low thermal conductivity of the coating further suppresses the heat exchange between the substrate-water droplets, so that the passive anti-icing / frosting performance of the coating is further improved. In addition, the present invention has the advantages of simple preparation method and large-area preparation, laying a solid foundation for the practical application of photothermal superhydrophobic anti-icing coatings.

The application belongs to the technical field of membrane separation materials, and discloses an ultrahydrophilic oil-water separation membrane, a preparation method and application thereof, and comprises the following steps: 2-(2-bromoisobutyryloxy)ethyl methacrylate monomers are prepared from 2-hydroxyethyl methacrylate and 2-bromoisobutyryl bromide, and a polymer with an atom transfer radical polymerization initiator is prepared through a free radical polymerization reaction; the polymer with the atom transfer radical polymerization initiator and polyacrylonitrile are dissolved into a solvent, and a PAN / P(AN-g-BIEM) blended membrane is prepared through a non-solvent induced phase separation method; and a hydrophilic polymer brush is grafted to the surface of the PAN / P(AN-g-BIEM) blended membrane to obtain the ultrahydrophilic oil-water separation membrane; the ultrahydrophilic oil-water separation membrane prepared by the application has a high separation flux, excellent oil-water separation efficiency and separation performance for different oil-in-water emulsions.

The application relates to a preparation method of a hollow fiber membrane composite thermal insulation material, which comprises the following steps: adding 18-22% of polyurethane, 4-8% of polyethylene glycol 2000 and 72-76% of N,N-dimethylacetamide into a spinning reaction kettle to mix, stir and defoam to prepare homogeneous casting solution; based on a non-solvent induced phase separation method, the homogeneous casting solution is coated on the surface of a polyester braided tube through a spinneret by adopting a concentric circle composite spinning technology, is gathered on a spinning wheel after a coagulation bath to form a reinforced polyurethane hollow fiber membrane assembly which is arranged in parallel and obliquely crosses and is mutually bonded, and the fiber membrane assembly is hot-pressed to prepare the hollow fiber membrane composite thermal insulation material under the conditions of a temperature of 60-150 DEG C and a pressure of 120-470 MPa. Since the coating layer and the braided tube are both through porous structures, the prepared composite material has good air permeability.

A method for producing a 3D porous sorbent structure may include building a 3D porous green body from a build material including a solvent, an inorganic porous sorbent material, and an organic binder material dissolved in the solvent. The build material is deposited as filaments in a plurality of stacked layers to obtain the 3D porous green body, and at least some of the filaments are spaced apart; inducing phase inversion of the body by exposing it to a non-solvent for the organic binder material. The solidified body is dried to obtain the 3D porous sorbent structure. The build material has 30-70% by weight of the inorganic porous sorbent material and 5-30% by weight of the organic binder material, based on the total weight of the build material, the 3D porous sorbent structure comprising at least a portion of the organic binder material.

The invention belongs to the technical field of adhesive tapes, and particularly relates to a UV protective film for packaging substrate cutting and a preparation method thereof.The UV protective film comprises a PO base material layer, a non-solvent type UV viscosity-reducing adhesive layer and a PET release layer, and the non-solvent type UV viscosity-reducing adhesive layer is located between the PO base material layer and the PET release layer; the non-solvent type UV viscosity-reducing adhesive layer comprises the following components: an acrylate soft monomer, an acrylate hydroxyl monomer, an acrylate hard monomer, an acrylate monomer with a space crosslinking site, n-dodecanethiol, a photoinitiator and a photosensitive multifunctional group acrylate monomer. The non-solvent type UV viscosity-reducing adhesive layer is introduced, so that the preparation process is environment-friendly and free of solvent volatilization, the UV protective adhesive is high in viscosity and excellent in impact resistance before UV irradiation, the adhesive layer is stably attached before cutting, and the UV protective film is stripped at low stress and free of residual adhesive after irradiation.

The invention belongs to the technical field of hydrogel high polymer materials, and particularly relates to a preparation method of high-strength and high-conductivity nano hydrogel and the hydrogel prepared by the preparation method. The preparation method of the hydrogel provided by the invention comprises the following steps: firstly, dissolving polyvinyl alcohol in a good solvent dimethyl sulfoxide of polyvinyl alcohol, and keeping an extended conformation and a staggered network; then, a poor solvent ethyl acetate of polyvinyl alcohol is introduced for non-solvent quenching, so that in-situ phase separation is promoted, polymer chains are drawn close, and interaction between the chains is enhanced; finally, neutral solvent water of polyvinyl alcohol is introduced for solvent replacement, the polymer microphase is evolved into nanofibers, and the polyvinyl alcohol hydrogel with nanoscale pores is formed. The hydrogel prepared by the invention has relatively high fracture stress strain and ionic conductivity, and effectively solves the problems of easy fracture, poor conductivity and the like of the traditional ionic thermoelectric gel.

The embodiment of the invention provides a carbon nanotube / fluorocarbon resin composite microsphere photo-thermal super-hydrophobic anti-condensation coating and a preparation method thereof.The preparation method comprises the steps that firstly, carbon nanotubes and fluorocarbon resin are evenly dispersed in a solvent, then a small amount of non-solvent water is added to enable a solution system to be subjected to phase separation, and carbon nanotube / fluorocarbon resin composite microsphere dispersion liquid is formed; and finally, spraying the carbon nanotube / fluorocarbon resin composite microsphere dispersion liquid, and curing to obtain the photo-thermal super-hydrophobic anti-condensation coating. The carbon nano tube is in a microsphere shape in the coating, so that a typical micro / nano coarse structure is obtained on the surface, the water drop contact angle of the coating is as high as 158 degrees, the icing delay time is as high as 434s, and the ice adhesion force is as low as 16kPa; under the irradiation of sunlight, the temperature of the coating can be increased to 54.5 DEG C within 10 minutes under the photo-thermal action of the carbon nanotubes, so that the melting of ice is accelerated.

The invention discloses a double-layer foaming porous polishing pad as well as a preparation method and application thereof, and relates to a double-layer pore structure chemical mechanical polishing pad, the upper part of a polishing layer of the polishing pad is provided with closely distributed finger-shaped pores, the average inner diameter is 0.17-0.25 mm, and the pore wall thickness of the finger-shaped pores is 15-20 microns; the lower part of the polishing layer is a sponge hole layer, and the average inner diameter of the sponge hole layer is 5-10 microns; the main body structure of the polishing layer is prepared from coating slurry comprising polyurethane resin, polyvinyl chloride resin and ethyl acetate in a coagulating bath through a non-solvent phase inversion method. The rebound rate of the polishing pad can be effectively improved by controlling the relative thickness of the double-layer holes of the polishing layer, the abrasion resistance of the polishing pad is remarkably improved through resin blending, the service life is prolonged, meanwhile, the hardness of the polishing layer is moderate, and product defects are effectively reduced. The polishing pad has excellent wear resistance and moderate hardness, the service life is remarkably prolonged, particle defects in the polishing process are reduced, and the polishing pad is suitable for a high-precision polishing process.

The application belongs to the technical field of composite membrane materials, and particularly relates to a preparation method and application of a super-hydrophilic composite membrane capable of removing various pollutants in water bodies; the preparation method comprises the following steps: preparing a bimetallic organic framework material FeZr-MOF through a one-step solvothermal method; dispersing FeZr-MOF powder in a suitable solvent, mixing, adding polyvinylidene fluoride and polyvinylpyrrolidone, stirring under water bath conditions at 30-80 DEG C, obtaining a uniformly mixed casting solution, and then preparing a FeZr-MOF / PVDF composite membrane through a non-solvent induced phase separation method after ultrasonic defoaming treatment; then, a polyaniline coating layer is in-situ polymerized on the surface of the composite membrane to obtain a PANI / FeZr-MOF / PVDF composite membrane. The super-hydrophilic composite membrane capable of removing various pollutants in water bodies has good effects in oil-water separation, removal of antibiotics and chromium ions in water and the like.

A photoresist composition comprising one or more non-solvent alkali-insoluble substrates present in a total amount exceeding 50% by weight based on the total solids content of the photoresist composition, and a nonpolymeric ionic photoacid generator compound comprising an anion and an iodonium or sulfonium cation, wherein the anion is defined by formula (1) as defined herein. [Formula 1] TIFF2026528972000047.tif49166(wherein b is an integer from 1 to 4, and at least one R) 1 (This is a group that is substituted with a halogen.) A photoresist composition comprising a nonpolymeric ionic photoacid generator compound and a solvent, as represented by [formula].

The application discloses a kind of polymer porous membrane, its preparation method and application in turbidity removal pre-filtering, belong to the technical field of porous membrane preparation.Its technical scheme includes: when the non-solvent phase separation of film-forming polymer solution occurs and the separation layer is formed on the outer surface of polymer membrane, simultaneously, water-soluble coating layer polymer solution is coated on the surface of separation layer, to obtain polymer porous membrane;Film-forming polymer solution uses polysulfone polymer as film-forming base material, uses water-soluble chloride as porogen, uses nitrogen-containing organic matter as solvent;Coating layer polymer solution has porogen effect, and viscosity is 200-1000 mPa·s.The application is applied to turbidity removal pre-filtering, solves the technical problems that existing non-solvent phase separation technology is difficult to obtain large aperture, surface opening rate is high and easy to appear finger-shaped hole, has the characteristics of large aperture, surface opening rate is high, cross section is sponge hole.

A salt-philic solvent-phobic (SP2) polymer coating on a lithium anode, sodium anode, or a silicon anode selectively transports salt over solvent and is configured to promote salt-derived SEI formation on the anode. The SP2 coating can include a polymer backbone, a first side chain comprising a first moiety having salt affinity, and a second side chain comprising a second moiety immiscible with polar aprotic solvents.

The invention relates to the technical field of membrane separation, in particular to a composite ultrafiltration membrane based on blending modification and surface modification and a preparation method and application thereof. The method comprises the following steps: firstly, preparing a polydopamine functionalized multi-walled carbon nanotube through oxidation cross-linking auto-polymerization and adhesion of a dopamine compound in an aqueous solution; dissolving a film-forming polymer, a pore-foaming agent and the prepared polydopamine functionalized multi-walled carbon nanotube in an organic solvent, degassing, and preparing a blend film by adopting a non-solvent induced phase separation method; the prepared blended membrane is sequentially and alternately immersed in a tannic acid solution and an aluminum salt solution, a tannic acid-aluminum ion metal phenolic aldehyde network layer is formed on the surface of the blended membrane through a coordination-driven layer-by-layer self-assembly method, and the composite ultrafiltration membrane is obtained. The composite ultrafiltration membrane prepared by the invention has high flux, high selectivity and excellent anti-pollution performance, and is especially suitable for treating and recycling wastewater containing organic macromolecules such as protein, colloid and the like.

A photoresist composition comprising one or more alkali-insoluble, non-solvent base materials present in a combined amount of more than 50 wt% based on the total solids of the photoresist composition; a non-polymeric ionic photoacid generator compound comprising an anion and an iodonium or sulfonium cation, the anion being represented by formula (1); a photodegradable quencher, a basic quencher or a combination thereof and a solvent: where Ar 1 for a monocyclic or polycyclic aromatic C 3-60 -Group stands; L 1 L represents a single bond or one or more binary linkage groups. 1 is free of fluorine; Z 1 an anion-stabilizing group, wherein Z 1is designed in such a way that it forms an intramolecular non-covalent bond with the sulfonate anion group, forming a ring with 5 to 8 atoms; and the remaining substituents are defined as shown here.

The invention provides a cigarette flavor base formula sheet dosage data processing method, which comprises the following steps: carrying out component identification on a solvent component and a non-solvent component in a target cigarette flavor base formula sheet to obtain an identification result, according to a target standard sum, performing first difference value judgment on the sum of the dosages of different non-solvent components in the identification result, and according to a first difference value judgment result, correcting the target cigarette flavor base formula list to obtain a first correction result; correcting the first correction result according to a target precision requirement to obtain a second correction result; and according to the target standard sum, performing second difference judgment on the sum of the component dosages of the solvent component and the non-solvent component in the second correction result, and according to a second difference judgment result, performing polling correction on the second correction result to complete correction after a target difference is reached. The invention further provides a cigarette flavor base formula sheet dosage data processing device and electronic equipment.

A polymer film has a loofah-like structure. It has a fibrous framework structure formed by three-dimensional interwoven and interconnected polymer fibers and a three-dimensional interconnected network pore structure distributed in the fibrous framework structure. The polymer is an organic polymer and the fibrous framework structure is integrally formed by the polymer. The film has a volume porosity of from 50% to 95%. The film is obtained by means of a combination method for atomization pretreatment and non-solvent phase separation. The film can be used in the fields of gas filtration, liquid filtration, oil-water separation, adsorption materials, catalysis, pharmaceutical sustained release materials, anti-adhesion coatings, oil delivery and oil spill interception.

A photoresist composition comprising one or more non-solvent base-insoluble base materials present in a combined amount greater than 50 wt% based on the total solids of the photoresist composition; a non-polymeric ionic photoacid generator compound comprising an anion and an iodonium or sulfonium cation, wherein the anion is represented by formula (1); a photodecomposable quencher, a basic quencher, or a combination thereof; and a solvent, wherein Ar 1 is a monocyclic or polycyclic C 3‑60 aromatic group; L 1 is a single bond or one or more divalent linking groups, wherein L 1 contains no fluorine; Z 1 comprises an anion stabilizing group, wherein Z 1 is configured to form an intramolecular non-covalent bond with a sulfonate anion group to form a ring having 5 to 8 atoms; and the remaining substituents are as defined herein. (1)

The application discloses a polyketone filter membrane containing a composite pore structure and a preparation method thereof, and belongs to the technical field of organic filter membranes. Aliphatic polyketone is used as a main body resin, is uniformly mixed with an additive and a diluent dimethyl sulfoxide at 130-160 DEG C, and a filter membrane is prepared through a composite thermally induced phase separation method. The preparation method is simple, safe and environmentally friendly. The prepared membrane has the membrane structure characteristics of a non-solvent induced phase separation method and a thermally induced phase separation method, has a finger-shaped pore and a double-continuous net-shaped composite structure, and has a low price, good hydrophilicity and good solvent resistance. The aliphatic polyketone has a good application prospect in the field of membrane separation.

The application relates to a preparation method of a high-porosity high-flux asymmetric membrane, and belongs to the field of membrane separation technology. The preparation method of the high-porosity high-flux asymmetric membrane comprises the following steps: uniformly dissolving a polymer and a hydrophilic additive in an organic solvent to prepare a homogeneous casting solution; preparing a nascent membrane from the casting solution; then, performing atomization pretreatment on the nascent membrane; rapidly cooling the nascent membrane after the pretreatment; then, immersing the nascent membrane in a gel bath to form an asymmetric membrane; and performing multiple flushing and soaking on the asymmetric membrane in normal-temperature deionized water to obtain the high-porosity high-flux asymmetric membrane. The asymmetric membrane adopts a non-solvent atomization technology combined with cooling-induced crystallization, the non-solvent atomization is introduced into the surface of the nascent membrane, the solution is rapidly saturated by accurate temperature control, the crystal formation is triggered, the macroporous pores are formed, and the membrane porosity and flux are improved. The obtained asymmetric membrane has a macroporous network on the surface layer and a finger-shaped pore on the support layer, the porosity is 75% to 85%, the pure water flux is greatly improved, and the high-efficiency separation requirement is met.

The application provides a high-voltage and high electrochemical performance electrolyte for a low-temperature lithium ion battery, a preparation method and application thereof, and belongs to the technical field of low-temperature lithium ion batteries.The electrolyte comprises the following components: a lithium salt, a base solvent and a non-solvated cosolvent; the base solvent is one or a combination of two or more of linear siloxanes or nitriles; the non-solvated cosolvent is one or a combination of two or more of fluorinated silanes or stannanes; and the volume ratio of the base solvent and the non-solvated cosolvent is 5-9:1-5.The pseudo-coordination bond between Sn (Si) in the non-solvated cosolvent and O (N) in the base solvent can be used to effectively adjust the solvation structure of the electrolyte, so that high ion conductivity at low temperature is achieved; and the prepared electrolyte is applied to a lithium ion battery, and exhibits excellent high-voltage and long cycle stability and other electrochemical performances at low temperature, so that the electrolyte has a good application prospect.

A method for separating a first layer from a second layer in a multilayer structure is disclosed. The method comprises the step of contacting the multilayer structure with a treatment solution comprising a solvent and a non-solvent until the first layer is separated from the second layer. The first layer comprises a polymer, wherein the polymer is soluble in the solvent and the polymer is insoluble in the non-solvent. The separated layer, an article comprising the separated layer, and a use of the treatment solution to separate the first layer from the second layer in the multilayer structure are also disclosed.

The invention discloses a preparation method and application of a bio-based polyester porous membrane, an organic solvent is used as a poly-3-hydroxybutyrate-co-4-hydroxybutyrate solvent, water is used as a non-solvent, and a phase inversion method is adopted to prepare the porous membrane. By adjusting the concentration of the membrane casting solution and the temperature of the coagulating bath, the phase separation behavior in the membrane forming process is regulated and controlled, the poly-3-hydroxybutyrate-co-4-hydroxybutyrate porous membrane with a controllable structure is prepared, and the porous membrane is uniform in pore distribution and high in porosity. The preparation method of the green polymer porous membrane material, provided by the invention, has the advantages of low cost, simple method, easiness in operation, energy conservation, environment friendliness and the like, and has a wide application prospect in the fields of oil-water separation, lithium ion batteries and the like; the problems of non-uniform pore size distribution, poor repeatability and the like of the existing polyhydroxyalkanoate in the phase separation film forming process are solved.

The application discloses a kind of oil-containing water body separation membrane for refining process of Bupleurum volatile oil and preparation method and application.The preparation method of the application is first mixed and dissolved according to proportion with cellulose acetate and cellulose nitrate powder, form casting membrane liquid, and the base membrane is prepared using non-solvent phase conversion method;Second, the film is deacetylated;After that, it is soaked in acyl chloride n-hexane solution for crosslinking;Finally, by in-situ hydrolysis of silane coupling agent on the membrane surface, a hydrophobic surface is prepared, and an oil-containing water body separation membrane for refining process of Bupleurum volatile oil is obtained.This method forms a hydrophobic layer on the surface of the membrane, which strengthens the rapid passage of Bupleurum volatile oil molecules and inhibits the penetration of water;Using the oil-containing water body separation membrane avoids the formation of emulsion during oil-water separation, showing high separation efficiency and stability, and widening the application of cellulose acetate membrane in traditional Chinese medicine preparation process.

The invention relates to the technical field of radiation cooling materials, and discloses a double-layer film with high day and night radiation cooling power and a preparation method and application thereof. The preparation method comprises the following steps: uniformly mixing first inorganic particles, polyether sulfone and a first organic solvent to obtain a membrane casting solution; coating the coating on a glass substrate, and then immersing the glass substrate in a non-solvent coagulating bath for curing; after curing, taking out and drying to obtain a porous substrate film; uniformly mixing second inorganic particles, polyvinylidene fluoride and a second organic solvent to obtain a spraying solution; and spraying the spraying liquid on the surface of the porous substrate film, and drying to obtain the double-layer film with high day and night radiation cooling power. The PES / inorganic particle porous substrate is prepared through non-solvent induced phase separation, the PVDF / inorganic particle layer is sprayed on the surface of the PES / inorganic particle porous substrate, the double-layer radiation cooling film is constructed, high radiation cooling power can be kept at the same time in the daytime and at night, the preparation process is simple, and large-scale production can be achieved.

The application relates to a method for preparing a polysulfone nanofiltration membrane through a porous membrane surface thermal initiation polymerization crosslinking reaction, and belongs to the membrane separation technical field.The method comprises the following steps: 1) dissolving a polysulfone polymer and a thermal initiation polymerization small molecule in a suitable solvent, and preparing a homogeneous casting solution after adding an additive; 2) coating the casting solution on a substrate, immersing the substrate in a coagulation bath, and forming a polysulfone separation base film through non-solvent induced phase separation; and 3) heating the membrane embryo for a proper time length, and controlling the temperature to be slightly lower than the glass transition temperature of the polysulfone polymer, and meanwhile, the thermal initiation polymerization small molecule added in the step 1) can be polymerized to cause thermal crosslinking, so that a dense separation thin layer is formed on the surface of the polysulfone material, and a membrane embryo with nanofiltration separation performance is formed. The scheme is simple and easy to implement, the process design is ingenious, the selected polysulfone polymer material source is relatively wide, and the obtained polysulfone nanofiltration separation membrane has high permeability and retention rate.

The invention provides a biodegradable ammonium persulfate coating gel breaker for fracturing operation and a preparation method of the biodegradable ammonium persulfate coating gel breaker. The preparation method comprises the following steps: determining a mass ratio R of rosin glyceride to ethyl cellulose according to a target reservoir temperature T, and calculating a coating weight gain ratio coefficient K and the total mass of a coating material according to target delayed gel breaking time t; preparing a core material ammonium persulfate into a water phase, and emulsifying in an oil phase to form a reversed-phase microemulsion; a gradient interface deposition method is adopted, a coating solution A prepared from rosin glyceride and part of ethyl cellulose and a coating solution B prepared from the remaining ethyl cellulose are dropwise added in sequence, and a coating material is sequentially deposited on a core material liquid drop interface through pressure reduction to form a compact bottom layer and a slow-release main body layer; according to the invention, the coating layer is biodegradable, chlorine-free and corrosion-free, through the cooperation of the material ratio and the process, the accurate and controllable delay of the gel breaking time at high temperature is realized, the reservoir is effectively protected, and the fracturing effect is improved.

This invention relates to the field of coatings and discloses a peelable protective coating and its preparation method. The peelable protective coating comprises: a polyurethane mother liquor: 5-10 parts diisocyanate, 90-110 parts diol, 1-3 parts catalyst, 1-8 parts chain extender, 40-70 parts solvent, 2-5 parts triethylamine, and 45-55 parts deionized water; 15-30 parts reinforcing filler; and 3-10 parts production aids. This invention's coating can achieve excellent isolation and protection of the substrate with a dry film thickness of only 20-40 μm. The coating formed by this invention is acid and alkali resistant, and after protection, it can be peeled off entirely by hand without damaging the substrate or leaving any marks. Furthermore, the polyurethane mother liquor used in this invention is solvent-free, and the solvent can be recovered by vacuum distillation, making it practical and environmentally friendly. The coating preparation process is simple, and the curing method does not require high-temperature sintering, thus eliminating site limitations.

The invention discloses a bifunctional group copolymerization separation membrane with a main chain containing crown ether as well as a preparation method and application of the bifunctional group copolymerization separation membrane. According to the method, 2, 2 '-bis (3-sulfonated propoxy) biphenyl disodium and isatin are used as monomers, a bifunctional material with a main chain containing crown ether is prepared through a superacid catalyzed polycondensation reaction under the condition of a certain reaction temperature, and a pure product is obtained through a large amount of water washing; secondly, preparing the prepared sample into a film through a non-solvent phase transfer method. The prepared bifunctional group copolymerization separation membrane material with the main chain containing crown ether shows relatively good ion exchange capacity, permeation selectivity and stability for lithium element in waste liquid, is simple and convenient to operate and controllable in cost, and shows a good application prospect.

This invention provides a high-performance, high-precision gradient pore ultrafiltration membrane and its preparation method, belonging to the field of membrane preparation technology. Lithium chloride can alter the thermodynamic properties of the casting solution, affecting the aggregation state of polymer molecules and the phase separation process. CTAB has multiple functions in the phase inversion membrane preparation process; as a non-solvent additive, it regulates the phase separation behavior of the polymer PVDF, promoting the formation of more uniform nanoscale channels. DOP has a unique molecular structure and physicochemical properties, playing a multifaceted role in improving membrane performance; by inserting itself between PVDF molecular chains, it weakens the intermolecular forces, making the molecular chains more loosely arranged, thereby forming more interconnected channels and increasing flux. Simultaneously, it helps to form a narrow pore size distribution, reducing macropore defects and improving retention accuracy. This invention, through the mixing of the above substances, effectively achieves a high-porosity, nanoscale pore structure, realizing a high-performance, high-precision gradient pore ultrafiltration membrane preparation method.