CN115582031A

CN115582031A - Amphiphilic polyvinylidene fluoride hollow fiber dry film and preparation method thereof

Info

Publication number: CN115582031A
Application number: CN202211369231.0A
Authority: CN
Inventors: 包进锋; 沈红梅; 黄赋; 吕晓龙
Original assignee: Zhejiang Changxing Qiushi Membrane Technology Co ltd; Zhejiang Chuangqi Environmental Protection Technology Co ltd
Current assignee: Zhejiang Changxing Qiushi Membrane Technology Co ltd; Zhejiang Chuangqi Environmental Protection Technology Co ltd
Priority date: 2022-11-03
Filing date: 2022-11-03
Publication date: 2023-01-10

Abstract

The invention provides an amphiphilic polyvinylidene fluoride hollow fiber dry film and a preparation method thereof, and relates to the technical field of water treatment. The invention provides a preparation method of an amphiphilic polyvinylidene fluoride hollow fiber dry film, which comprises the following steps: forming a polyvinylidene fluoride solution through a mold, and then sequentially carrying out initiation polymerization, non-solvent phase inversion curing and cleaning to prepare an amphiphilic polyvinylidene fluoride hollow fiber dry film; the polyvinylidene fluoride solution comprises a hydrophilic monomer, a hydrophobic monomer, an initiator, polyvinylidene fluoride powder, a solvent and an additive. The preparation method has the advantages of simple and controllable production process and low manufacturing cost, and the prepared amphiphilic polyvinylidene fluoride hollow fiber dry film has the advantages of good hydrophilic property, high interception precision and high permeability, can be dried at high temperature, and abandons the traditional glycerin moisturizing process.

Description

Amphiphilic polyvinylidene fluoride hollow fiber dry film and preparation method thereof

Technical Field

The invention relates to the technical field of water treatment, in particular to an amphiphilic polyvinylidene fluoride hollow fiber dry film and a preparation method thereof.

Background

Among many membrane materials, polyvinylidene fluoride (PVDF), as a crystalline polymer membrane material, has excellent mechanical properties, thermal stability, chemical cleaning resistance, weather resistance, oxidation resistance, radiation resistance, etc., and has been widely used in the preparation of microfiltration ultrafiltration membranes. However, the PVDF separation membrane still has the following problems in application: (1) The hydrophobic property of the water-based cleaning agent enables the water-based cleaning agent to be easy to adsorb and pollute protein when treating water-based system solutions containing natural organic substances such as biochemical pharmacy, food and beverage, domestic sewage and the like, thereby increasing the cleaning cost and the operation cost; (2) Due to the extremely low surface energy of the hydrophobic PVDF membrane, the water flux of the microporous membrane is low, and the energy consumption is high; (3) The existing membrane preparation and modification methods often cause contradiction between flux and rejection rate, the flux is usually improved at the cost of reducing the rejection rate, and the flux is usually reduced by improving the rejection rate; (4) The membrane is usually moisturized by adding a protective liquid, which is not favorable for storage, transportation and use of the membrane, and is easy to breed bacteria to cause secondary pollution.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The first purpose of the invention is to provide a preparation method of the amphiphilic polyvinylidene fluoride hollow fiber dry film, which has low cost and simple production process.

A second object of the present invention is to provide an amphiphilic polyvinylidene fluoride hollow fiber dry film having high hydrophilicity, high permeation flux and high interception accuracy, which can solve at least one of the above problems.

In a first aspect, the invention provides a preparation method of an amphiphilic polyvinylidene fluoride hollow fiber dry film, which comprises the following steps:

forming a polyvinylidene fluoride solution through a mold, and then sequentially carrying out initiation polymerization, non-solvent phase inversion curing and cleaning to prepare an amphiphilic polyvinylidene fluoride hollow fiber dry film;

the polyvinylidene fluoride solution comprises a hydrophilic monomer, a hydrophobic monomer, an initiator, polyvinylidene fluoride powder, a solvent and an additive.

As a further technical scheme, the hydrophilic monomer has an N-vinyl group and comprises at least one of N-vinyl pyrrolidone, N-vinyl acetamide, N-vinyl imidazole, N-vinyl caprolactam and N-vinyl formamide;

the hydrophobic monomer comprises propylene oxide;

the initiator is a radiation initiator and comprises a water-soluble peroxydisulfate initiator and a transition metal ion co-initiator;

the water-soluble peroxydisulfate initiator comprises sodium peroxydisulfate, potassium peroxydisulfate or ammonium peroxydisulfate; the transition metal ion co-initiator comprises iron/ferrous, copper/cuprous, tetravalent cerium/trivalent cerium, cobalt/cobaltous, vanadate (V)/vanadate (IV), permanganate and manganese/manganous;

the solvent is a water-soluble solvent and comprises at least one of triethyl phosphate, N-dimethylformamide, N-dimethylacetamide, dimethyl sulfoxide and N-methylpyrrolidone;

the additive is an alcohol or acid additive and comprises at least one of glycol, glycol polymer, glycerol, dicarboxylic acid and citric acid.

As a further technical scheme, in the polyvinylidene fluoride solution, the content of hydrophilic monomers is 1-10 wt.%, the content of hydrophobic monomers is 1-10 wt.%, the content of initiators is 0.01-5 wt.%, the content of polyvinylidene fluoride powder is 10-25 wt.%, the content of solvents is 25-88 wt.%, and the content of additives is 1-25 wt.%;

preferably, in the polyvinylidene fluoride solution, the content of the hydrophilic monomer is 3wt.%, the content of the hydrophobic monomer is 3wt.%, the content of the initiator is 0.6wt.%, the content of the polyvinylidene fluoride powder is 17wt.%, the content of the solvent is 66.4wt.%, and the content of the additive is 10wt.%.

As a further technical scheme, the mould is formed by molding the polyvinylidene fluoride solution through a hollow fiber mould under the pressurizing condition.

As a further technical scheme, the method also comprises defoaming and filtering before the mould is formed.

As a further technical scheme, the initiation polymerization comprises ultraviolet radiation initiation polymerization, and the radiation time is 5-100 s.

As a further technical scheme, the non-solvent phase inversion curing is to immerse the molding material after the initiation of polymerization into a coagulating bath;

preferably, the coagulation bath contains at least 20wt.% of an alcohol non-solvent;

preferably, the alcohol non-solvent includes at least one of ethylene glycol, a dimer of ethylene glycol, and glycerol.

As a further technical solution, the washing comprises water washing;

preferably, the temperature for cleaning is 40-80 ℃;

preferably, the cleaning further comprises drying;

preferably, the temperature of the drying is 40 to 60 ℃.

In a second aspect, the invention provides an amphiphilic polyvinylidene fluoride hollow fiber dry film, which is prepared by adopting the preparation method.

As a further technical scheme, the water content of the amphiphilic polyvinylidene fluoride hollow fiber dry film is less than or equal to 1wt.%, the static hydrophilic contact angle is less than or equal to 40 degrees, the dynamic water contact angle penetration time is less than or equal to 15s, the average pore diameter is less than or equal to 100nm, and the pure water penetration performance is more than or equal to 1000LMH/bar.

Compared with the prior art, the invention has the following beneficial effects:

the PVDF hollow fiber membrane is modified by in-situ polymerization of an amphiphilic polymer. The hydrophilic monomer, the hydrophobic monomer and the PVDF resin are fully mutually soluble, after the hydrophilic monomer and the hydrophobic monomer are initiated, the hydrophilic monomer and the hydrophobic monomer are subjected to polymerization reaction, and the generated amphiphilic polymer is entangled with PVDF molecular chains to form an interpenetrating network structure. The structure enables a large number of physical cross-linking points to be formed between two molecules, and the amphiphilic polymer can be lost only after the material is aged and a molecular chain is broken if you are your and your, so that the hydrophilic effect is more durable, and the hydrophilic effect is represented as a lower water contact angle and a higher pure water flux at the beginning. The obtained polyvinylidene fluoride hollow fiber membrane can be dried at high temperature, the traditional glycerol moisturizing process is abandoned, the storage and transportation cost of the membrane is reduced, and the polyvinylidene fluoride hollow fiber membrane is a dry membrane capable of being repeatedly wetted and dried. The preparation method has the advantages of simple and controllable production process and low manufacturing cost, and the prepared amphiphilic polyvinylidene fluoride hollow fiber dry film has the advantages of good hydrophilic property, high interception precision and high permeability.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic flow diagram of a method for preparing the amphiphilic PVDF hollow fiber dry film of example 1;

FIG. 2 is the dynamic water contact angle of the amphiphilic PVDF hollow fiber dry film of example 1;

fig. 3 is a pore size distribution of the amphiphilic PVDF hollow fiber dry film of example 1.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to embodiments and examples, but those skilled in the art will understand that the following embodiments and examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Those who do not specify the conditions are performed according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

In general, the blending modification of the amphiphilic polymer is carried out by utilizing the hydrophobic interaction between a hydrophobic connecting segment in the amphiphilic polymer and PVDF molecules, but the intermolecular force action is limited, and the amphiphilic polymer gradually runs off from the blending modified PVDF hollow fiber membrane under the action of long-time flowing water scouring and molecular chain movement, so that the hydrophilicity of the membrane material is reduced. The PVDF hollow fiber membrane is modified by in-situ polymerization of amphiphilic polymer. The hydrophilic monomer, the hydrophobic monomer and the PVDF resin are fully mutually soluble, after the hydrophilic monomer and the hydrophobic monomer are initiated, the hydrophilic monomer and the hydrophobic monomer are subjected to polymerization reaction, and the generated amphiphilic polymer is entangled with PVDF molecular chains to form an interpenetrating network structure. The structure enables a large number of physical cross-linking points to be formed between two molecules, and the amphiphilic polymer can be lost only after the material is aged and a molecular chain is broken if you are your and your, so that the hydrophilic effect is more durable, and the hydrophilic effect is represented as a lower water contact angle and a higher pure water flux at the beginning. The obtained polyvinylidene fluoride hollow fiber membrane can be dried at high temperature, the traditional glycerol moisturizing process is abandoned, the storage and transportation cost of the membrane is reduced, and the polyvinylidene fluoride hollow fiber membrane is a dry membrane capable of being repeatedly wetted and dried.

In some preferred embodiments, the hydrophilic monomer has an N-vinyl group including, but not limited to, at least one of N-vinylpyrrolidone, N-vinylacetamide, N-vinylimidazole, N-vinylcaprolactam, and N-vinylformamide;

the hydrophobic monomer comprises propylene oxide;

the initiator is a radiation initiator, including but not limited to water-soluble peroxodisulfate initiators and transition metal ion co-initiators;

the water soluble peroxodisulfate initiator includes, but is not limited to, sodium peroxodisulfate, potassium peroxodisulfate, or ammonium peroxodisulfate; the transition metal ion co-initiator comprises iron/ferrous, copper/cuprous, tetravalent cerium/trivalent cerium, cobalt/cobaltous, vanadate (V)/vanadate (IV), permanganate and manganese/manganous;

the solvent is a water-soluble solvent, and comprises at least one of triethyl phosphate, N-dimethylformamide, N-dimethylacetamide, dimethyl sulfoxide and N-methylpyrrolidone;

the additive is an alcohol or acid additive, including but not limited to at least one of ethylene glycol, a polymer of ethylene glycol, glycerol, dicarboxylic acid, citric acid.

In some preferred embodiments, the amount of hydrophilic monomer in the polyvinylidene fluoride solution can be, for example, but not limited to, 1wt.%, 2wt.%, 4wt.%, 6wt.%, 8wt.%, or 10wt.%, preferably 3wt.%;

the amount of hydrophobic monomer is 1wt.%, 2wt.%, 4wt.%, 6wt.%, 8wt.% or 10wt.%, preferably 3wt.%;

the amount of initiator is 0.01wt.%, 0.02wt.%, 0.05wt.%, 0.1wt.%, 0.2wt.%, 0.5wt.%, 1wt.%, 2wt.% or 5wt.%, preferably 0.6wt.%;

the content of polyvinylidene fluoride powder is 10wt.%, 15wt.%, 20wt.% or 25wt.%, preferably 17wt.%;

the amount of solvent is 25wt.%, 45wt.%, 65wt.% or 88wt.%, preferably 66.4wt.%;

the content of the additive is 1wt.%, 5wt.%, 10wt.%, 15wt.%, 20wt.% or 25wt.%, preferably 10wt.%.

Through further optimization and adjustment of each component and proportion in the polyvinylidene fluoride solution, the reaction is sufficient, and the hydrophilic effect is durable.

In some preferred embodiments, the mold is formed by molding the polyvinylidene fluoride solution through a hollow fiber mold under a pressurized condition, the invention is not limited to the pressure, and the polyvinylidene fluoride solution can be formed, for example, under a pressure of 0.2 Mpa.

In some preferred embodiments, the polyvinylidene fluoride solution may be formulated, for example, as: adding a hydrophilic monomer, a hydrophobic monomer, an initiator, polyvinylidene fluoride powder, a solvent, and an alcohol or acid additive into a dissolving kettle according to the proportion of a membrane-making liquid, and heating, stirring and dissolving under a protective atmosphere.

In some preferred embodiments, deaeration and filtration are further included prior to molding the mold.

The polyvinylidene fluoride solution may contain air bubbles and solid impurities, and in order to avoid structural defects of the hollow fiber membrane, the polyvinylidene fluoride solution is preferably subjected to deaeration and filtration before the mold is formed, and the deaeration and filtration may be performed in a manner known to those skilled in the art.

In some preferred embodiments, the initiating polymerization comprises ultraviolet radiation initiating polymerization, and the radiation may be for a time period of, for example, but not limited to, 5s, 10s, 20s, 40s, 60s, 80s, or 100s.

In some preferred embodiments, the non-solvent phase inversion curing is to immerse the polymerization-initiated form in a coagulation bath;

In some preferred embodiments, the washing comprises water washing to remove solvent, alcohol, or acid soluble materials;

preferably, the temperature of the washing may be, for example, but not limited to, 40 ℃, 50 ℃, 60 ℃, 70 ℃ or 80 ℃ to accelerate dissolution of the soluble material;

preferably, the cleaning is further followed by drying to remove excess moisture;

preferably, the temperature of the drying may be, for example, but not limited to, 40 ℃, 45 ℃, 50 ℃, 55 ℃ or 60 ℃.

In a second aspect, the invention provides an amphiphilic polyvinylidene fluoride hollow fiber dry film which is prepared by the preparation method.

Tests show that the water content of the amphiphilic polyvinylidene fluoride hollow fiber dry film prepared by the preparation method is less than or equal to 1wt.%, the static hydrophilic contact angle is less than or equal to 40 degrees, the dynamic water contact angle penetration time is less than or equal to 15s, the average pore diameter is less than or equal to 100nm, and the pure water permeability is more than or equal to 1000LMH/bar.

The invention is further illustrated by the following specific examples and comparative examples, but it should be understood that these examples are for purposes of illustration only and are not to be construed as limiting the invention in any way.

Example 1

A method for manufacturing an amphiphilic polymer in-situ polymerization modified polyvinylidene fluoride hollow fiber dry film (amphiphilic polyvinylidene fluoride hollow fiber dry film) comprises the following steps:

(1) Preparing a polyvinylidene fluoride solution: adding 3wt.% of hydrophilic monomer N-vinyl pyrrolidone, 3wt.% of hydrophobic monomer propylene oxide, 0.5wt.% of ammonium peroxodisulfate and 0.1wt.% of ferric sulfate/ferrous iron as a radiation initiator, 17wt.% of PVDF powder (Solvay 1015), 66.4wt.% of solvent N, N-dimethylacetamide and 10wt.% of polyethylene glycol 400 into a dissolving kettle, heating to 70 ℃ under the protection of nitrogen, and stirring for dissolving;

(2) Forming through a die: standing, defoaming and filtering the PVDF solution prepared in the step (1), and then forming a primary formed product through a hollow fiber mould (model phi 54X phi 2.8X phi 2.0X phi 1.75) under the pressure of 0.2 MPa;

(3) Polymerization and non-solvent phase inversion curing by radiation initiation: initiating polymerization by ultraviolet radiation before the formed product obtained in the step (2) is immersed in a water bath of 30% polyethylene glycol 400 for solidification, wherein the radiation time is 20s, and obtaining a PVDF hollow fiber membrane;

(4) The solubles were removed and dried: and (3) leaching the PVDF hollow fiber membrane obtained in the step (3) in hot water at 60 ℃ for 5 stages to remove soluble substances such as solvents N, N-dimethylacetamide and polyethylene glycol 400, and drying in hot air at 60 ℃ to obtain the amphiphilic polymer in-situ polymerization modified PVDF hollow fiber dry membrane. The PVDF hollow fiber dry film modified by the in-situ polymerization of the amphiphilic polymer obtained by the method is a hollow fiber film with the outer diameter of 2.0mm and the wall thickness of 100 mu m.

Example 2

A method for manufacturing an amphiphilic polyvinylidene fluoride hollow fiber dry film, an experimental process is shown in figure 1, and the method comprises the following steps:

(1) Preparing a polyvinylidene fluoride solution: adding 10wt.% of hydrophilic monomer N-vinyl acetamide, 10wt.% of hydrophobic monomer propylene oxide, 4wt.% of potassium peroxodisulfate and 1wt.% of copper sulfate/cuprous sulfate as a radiation initiator, 10wt.% of PVDF powder (Solvay 1015), 64wt.% of solvent triethyl phosphate and 1wt.% of glycerol into a dissolving kettle, heating to 70 ℃ under the protection of nitrogen, and stirring to dissolve;

(2) Forming through a die: standing, defoaming and filtering the PVDF solution prepared in the step (1), and forming a preliminary formed object through a hollow fiber mould (model phi 54X phi 2.8X phi 2.0X phi 1.75) under the pressure of 0.2 MPa;

(3) Polymerization initiated by radiation and non-solvent phase inversion curing: initiating polymerization by ultraviolet radiation before the formed product obtained in the step (2) is immersed in a water bath containing 20% of glycerol for solidification, wherein the radiation time is 100s, and obtaining a PVDF hollow fiber membrane;

(4) The solubles were removed and dried: and (4) leaching the PVDF hollow fiber membrane obtained in the step (3) in hot water at 60 ℃ for 5 grades to remove soluble substances such as triethyl phosphate and glycerol, and drying in hot air at 60 ℃ to obtain the amphiphilic polymer in-situ polymerization modified PVDF hollow fiber dry membrane.

Example 3

A method for manufacturing an amphiphilic polyvinylidene fluoride hollow fiber dry film comprises the following steps:

(1) Preparing a polyvinylidene fluoride solution: 2wt.% of hydrophilic monomer N-vinyl caprolactam, 1wt.% of hydrophobic monomer propylene oxide, 0.08wt.% of sodium peroxodisulfate and 0.02wt.% of cobalt sulfate/cobaltous, 25wt.% of PVDF powder (Solvay 1015), 46.9wt.% of solvent dimethyl sulfoxide and 25wt.% of ethylene glycol are added into a dissolving kettle and heated to 70 ℃ under the protection of nitrogen gas to be dissolved by stirring;

(3) Polymerization and non-solvent phase inversion curing by radiation initiation: initiating polymerization by ultraviolet radiation before the formed product obtained in the step (2) is immersed in a water bath of 60% glycol for solidification, wherein the radiation time is 5s, and obtaining a PVDF hollow fiber membrane;

(4) The solubles were removed and dried: and (3) leaching the PVDF hollow fiber membrane obtained in the step (3) in hot water at 60 ℃ for 5 stages to remove soluble substances such as dimethyl sulfoxide, ethylene glycol and the like, and drying in hot air at 60 ℃ to obtain the amphiphilic polymer in-situ polymerization modified PVDF hollow fiber dry membrane.

Comparative example 1

A hollow fiber membrane is prepared by the following steps:

(1) Preparing a polyvinylidene fluoride solution: adding 6wt.% of amphiphilic polymer PVP-PPO, 17wt.% of PVDF powder (Solvay 1015), 67wt.% of solvent N, N-dimethylacetamide and 10wt.% of polyethylene glycol 400 into a dissolving kettle, heating to 70 ℃ under the protection of nitrogen, and stirring for dissolving;

(3) Curing by non-solvent phase inversion: flying the formed product obtained in the step (2) in the air for 20s before being immersed in a water bath of 30% polyethylene glycol 400 for solidification to obtain a PVDF hollow fiber membrane;

(4) The solubles were removed and dried: and (3) leaching the PVDF hollow fiber membrane obtained in the step (3) in hot water at 60 ℃ for 5 grades to remove soluble substances such as solvents N, N-dimethylacetamide and polyethylene glycol 400, and drying in hot air at 60 ℃ to obtain the amphiphilic polymer blending modified PVDF hollow fiber dry membrane.

The amphiphilic polymer blending modified PVDF hollow fiber dry film obtained by the comparative example is a hollow fiber film with the outer diameter of 2.0mm and the wall thickness of 100 mu m.

Test example 1

The performance of the hollow fiber membranes prepared in example 1 and comparative example 1 was measured as follows:

(1) Pure water flux (LMH/bar)

Fully wetting the membrane with water, folding two hollow membranes with the effective length of 50cm into a U shape, filling the U-shaped hollow membranes or flat membrane with the effective diameter of 5cm into a flat mold, testing the stable permeation flow rate of the pure water of the membrane at the pressure of 0.1MPa and the temperature of 25 ℃, and calculating the flow rate of unit time and unit area, namely the pure water flux of the membrane.

(2) Determination of contact Angle

The film sample was applied flat to a slide glass with double sided tape and vacuum dried at 40 ℃ for 24 hours. The dynamic contact angle and the static contact angle of the sample film were measured with a video optical contact angle tester (OCA 50AF, dataphysics, germany) having a high-speed image pickup function. And (3) lightly touching 3 mu l of deionized water on the surface of the sample film, acquiring a dynamic image of the liquid drop changing along with time by using a camera, and fitting by corresponding software to obtain a dynamic contact angle.

(3) Determination of hydrophilic stability

Fully wetting the membrane with water, folding two hollow membranes with the effective length of 50cm into a U shape, filling the U-shaped hollow membranes or flat membrane with the effective diameter of 5cm into a flat mold, operating at the temperature of 25 ℃ for 48h at the constant flow of 60LMH pure water flux, taking out a membrane sample, and testing the contact angle.

(4) Determination of membrane pore size

And (3) wetting a membrane sample by using ethanol or Isopar G liquid, and then determining the pore size distribution and the average pore size of the membrane by using a gas-liquid displacement capillary flow pore size analyzer.

As shown in fig. 2 and 3, the hollow fiber membrane provided in example 1 was measured to have a static hydrophilic contact angle of 32 °, a dynamic water contact angle permeation time of 8s, an average pore diameter of 21nm, a pure water permeation performance of 1200LMH/bar, a static hydrophilic contact angle of 34 ° after 48h of operation, and a dynamic water contact angle permeation time of 8s. The hollow fiber membrane provided in comparative example 1 had a static hydrophilic contact angle of 65 °, a dynamic water contact angle permeation time of 28s, an average pore size of 25nm, a pure water permeability of 980LMH/bar, a static hydrophilic contact angle of 72 ° after 48h of operation, and a dynamic water contact angle permeation time of 42s.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. The preparation method of the amphiphilic polyvinylidene fluoride hollow fiber dry film is characterized by comprising the following steps:

2. The method of claim 1, wherein the hydrophilic monomer has an N-vinyl group and includes at least one of N-vinylpyrrolidone, N-vinylacetamide, N-vinylimidazole, N-vinylcaprolactam, and N-vinylformamide;

the hydrophobic monomer comprises propylene oxide;

3. The method according to claim 1, wherein the polyvinylidene fluoride solution contains 1 to 10wt.% of hydrophilic monomer, 1 to 10wt.% of hydrophobic monomer, 0.01 to 5wt.% of initiator, 10 to 25wt.% of polyvinylidene fluoride powder, 25 to 88wt.% of solvent, and 1 to 25wt.% of additive;

4. The method of claim 1, wherein the die is shaped by passing the polyvinylidene fluoride solution through a hollow fiber die under pressure.

5. The method of claim 1, further comprising debubbling and filtering before the mold is formed.

6. The method of claim 1, wherein the initiating polymerization comprises ultraviolet radiation initiated polymerization for a period of time ranging from 5 to 100 seconds.

7. The preparation method according to claim 1, wherein the non-solvent phase inversion curing is performed by immersing the polymerization-initiated molding in a coagulation bath;

8. The production method according to claim 1, wherein the washing includes water washing;

preferably, the temperature for cleaning is 40-80 ℃;

preferably, the washing further comprises drying;

preferably, the drying temperature is 40 to 60 ℃.

9. An amphiphilic polyvinylidene fluoride hollow fiber dry film, which is characterized by being prepared by the preparation method of any one of claims 1 to 8.

10. The amphiphilic polyvinylidene fluoride hollow fiber dry film according to claim 9, wherein the amphiphilic polyvinylidene fluoride hollow fiber dry film has a water content of not more than 1wt.%, a static hydrophilic contact angle of not more than 40 °, a dynamic water contact angle permeation time of not more than 15s, an average pore diameter of not more than 100nm, and pure water permeability of not less than 1000LMH/bar.