WO2017107317A1

WO2017107317A1 - Method for modifying polymer separation membrane by means of ultrasonic in-situ polymerization

Info

Publication number: WO2017107317A1
Application number: PCT/CN2016/076029
Authority: WO
Inventors: 秦舒浩; 邵会菊; 韦福建; 吴斌; 罗大军; 张凯舟; 张敏敏; 姚勇; 杨敬葵; 崔振宇
Original assignee: 贵州省材料产业技术研究院
Priority date: 2015-12-22
Filing date: 2016-03-10
Publication date: 2017-06-29
Also published as: JP6715348B2; JP2019507011A; CN105597562A; CN105597562B

Abstract

A method for modifying a polymer membrane by means of ultrasonic in-situ polymerization, and a polymer separation membrane prepared using the method. Nearby polymer macromolecules or micromolecules are cracked to generate free radicals by means of the cavitation effect of ultrasonic waves, thereby initiating monomers to be grafted on the surface of a base membrane and undergo an in-situ polymerization reaction to form a copolymer modified thin layer. The polymerized monomers selected are conventional, easily available, and low in cost. Moreover, the preparation method is simple, the operation process is controllable, and the membrane material obtained by modification has stable and long-lasting hydrophilic performance, and therefore has a good separation effect when applied to water treatment.

Description

Method for modifying polymer separation membrane by ultrasonic in-situ polymerization

Technical field

The invention relates to the technical field of polymer materials, in particular to a method for modifying a polymer separation membrane by ultrasonic in-situ polymerization.

Background technique

Film products prepared from polymer materials such as polypropylene, polyethylene, and polyvinylidene fluoride have low raw material prices, good acid, alkali and salt solution properties and chemical stability, and high mechanical strength has become the most widely used. Membrane products. However, there is a major disadvantage in the preparation of liquid separation membranes from such materials, that is, their hydrophobicity is strong. In the application of water treatment process, the hydrophobic membrane resists the adhesion and affinity of water molecules due to its surface free energy, resulting in large transmembrane pressure and low water flux. At the same time, the hydrophobic membrane easily adsorbs organic matter and microorganisms, thereby causing pollution. Therefore, the hydrophilic modification technique has become a key technology for preparing a polymer hollow fiber membrane excellent in performance.

A variety of different methods have been developed for the surface modification of polymer microporous membranes, which are mainly divided into chemical methods and physical methods. There are many methods for chemical modification, including simple treatment with corona, ultraviolet, plasma, etc., and grafting some hydrophilic groups onto the matrix material to improve the hydrophilic properties of the material. However, the hollow fiber membrane obtained by this modification method is not hydrophilic inside, so the efficiency is relatively low. In addition, this method requires more severe conditions and expensive equipment, damage to the membrane, poor hydrophilization, and poor durability. The physical modification method, such as coating method, treats the microporous membrane with a hydrophilic agent (such as an alcohol, a surfactant, a polyelectrolyte complex, etc.) or directly immerses the microporous membrane in a polymer solution, and then evaporates the solvent.

Although this technique is simple, since the surface modifier is fixed only by physical adsorption, the surface modifier is easily lost, and the hydrophilicity gradually decreases during use.

Summary of the invention

The technical problem existing in the prior art is that the existing chemically modified polymer material is not hydrophilic inside the hollow fiber membrane and requires severe conditions and expensive equipment to damage the membrane; The treatment of the polymer microporous membrane by the physical modification method is to fix the surfactant by physical adsorption, and there is a defect that the surface modifier is easily lost and the hydrophilicity gradually decreases during use.

The invention aims to provide a method for modifying a polymer separation membrane by ultrasonic in-situ polymerization, which has a simple preparation process, and the prepared hollow fiber membrane has an efficient and long-lasting hydrophilic effect, and is applied to water treatment. It has a good separation effect to overcome the deficiencies of the prior art.

The problem of the prior art in order to solve the problems of the prior art is to achieve polymer separation membrane modification by providing the following technical solutions:

A method for modifying a polymer separation membrane by ultrasonic in-situ polymerization, which comprises the following steps:

1) dissolving the polymerization monomer and the initiator in an organic solvent to prepare a uniform solution;

2) immersing the polymer separation membrane in the solution obtained in the step 1) for 24 hours, and then performing ultrasonic treatment to accelerate the diffusion and adsorption of the polymerization monomer and the initiator in the membrane material, so that they are sufficiently adsorbed on the surface of the membrane and Inside the membrane pores;

3) After the polymer separation membrane adsorbing the polymerization monomer and the initiator is taken out from the solution, it is immediately placed in an organic solvent, and the cavitation effect of the ultrasonic wave is used to generate radicals of the polymer macromolecule or small molecule, thereby The polymerized monomer is grafted on the surface of the base film containing the active point, and simultaneously polymerized in situ to form a copolymer modified layer;

4) The polymer separation membrane after the in-situ polymerization reaction is taken out and repeatedly washed with ethanol to remove residual oligomers and an excessive amount of the initiator to obtain a finished product.

Wherein, preferably, the method for modifying a polymer separation membrane by ultrasonic in-situ polymerization is characterized in that the polymer separation membrane is polypropylene, polyethylene, polysulfone, polyethersulfone or poly A vinylidene fluoride is a flat plate or a hollow fiber membrane of a material.

Wherein, preferably, the polymerizable monomer is a combination of one or a combination of styrene, maleic anhydride, acrylic acid, methacrylic acid or methyl methacrylate in any ratio.

Wherein, preferably, the organic solvent is ethanol, acetone or toluene.

Among them, preferably, the initiator is benzoyl peroxide.

Among them, preferably, the initiator is 0.1 to 0.5% of the total mass of the polymerized monomers.

In addition, the present invention also provides a method for modifying a polymer film by using ultrasonic in-situ polymerization, which comprises the following steps:

1) dissolving the polymerizable monomer and the initiator in a first organic solvent to prepare a uniform solution;

2) immersing the polymer film in the solution obtained in the step 1) for more than 24 hours, and then performing ultrasonic treatment to diffuse and adsorb the polymerizable monomer and the initiator in the film material and in the pores of the film;

3) After the polymer film adsorbing the polymerization monomer and the initiator is taken out from the solution, it is immediately placed in the first organic solvent, and the polymerized monomer is grafted to the base film containing the active site by the cavitation effect of the ultrasonic wave. In-situ polymerization in the surface and/or pores of the film to form a copolymer modified layer;

4) The polymer separation membrane after the in-situ polymerization reaction is taken out and rinsed with a second organic solvent to obtain a polymer film modified product.

Wherein, preferably, the polymer film is a flat plate or a hollow fiber membrane made of polypropylene, polyethylene, polysulfone, polyethersulfone or polyvinylidene fluoride.

Wherein, preferably, the polymerizable monomer is a combination of one or a combination of styrene, maleic anhydride, acrylic acid, methacrylic acid or methyl acrylate or methyl methacrylate in any ratio.

Wherein, preferably, the first organic solvent and the second organic solvent are each independently obtained from ethanol, acetone or toluene.

Among them, preferably, the initiator is benzoyl peroxide.

Among them, preferably, the initiator is from 0.1 to 0.5%, more preferably from 0.1 to 0.3%, based on the mass of the polymerizable monomer.

Among them, preferably, the mass ratio of the total amount of the polymerized monomers to the polymer film is from 1 to 6%.

Wherein, preferably, in the step (2), the temperature is from room temperature to 50 ° C; preferably, the frequency of the ultrasonic wave is 40 kHz; more preferably, the ultrasonic power is from 100 to 500 W; more preferably, the ultrasonic intensity is from 600 to 2000 W/ m ² ; more preferably, the ultrasonic time is 1-3 h.

Wherein, preferably, in the step (3), the temperature is from 60 ° C to 80 ° C; preferably, the frequency of the ultrasonic wave is 60 kHz; more preferably, the ultrasonic power is from 100 to 700 W; more preferably, the ultrasonic intensity is from 600 to 5000 W /m ² ; More preferably, the ultrasonic time is 1-6 h.

Wherein, preferably, in the step (1), the ratio of the total mass of the polymerized monomer to the volume of the first organic solvent is 0.05-0.12 g/mL, 0.06-0.08 g/mL.

Due to the adoption of the above technical solution, the present invention utilizes the cavitation effect of ultrasonic waves to cleave nearby polymer macromolecules or small molecules to generate free radicals, thereby inducing monomer grafting on the surface of the base film and or film. The in-situ polymerization is carried out in the pores to form a copolymer modified thin layer. The polymerization monomer selected by the invention is conventionally available, the cost is low, the preparation method is simple, the operation process is controllable, the membrane material obtained by the modification has a porosity of 62-89%, and the pure water flux reaches 256 L/m ^{2 .} Above h, the pure water flux after modification is increased by more than 50% compared with that before modification, and can even be increased to 160%. Therefore, the hydrophilic property is stable and durable, and it has good separation effect in water treatment. .

DRAWINGS

1 is a schematic view of an ultrasonic in-situ polymerization process of the present invention.

detailed description

The present invention provides a method for modifying a polymer film, preferably a polymer separation membrane. In a preferred embodiment, the present invention provides a method for modifying a polymer separation membrane by ultrasonic in-situ polymerization, the method Including the following steps:

3) The polymer separation membrane adsorbing the polymerization monomer and the initiator is taken out from the solution, immediately placed in an organic solvent, and subjected to ultrasonic treatment, and the macromolecule or small molecule of the polymer is freely utilized by the cavitation effect of the ultrasonic wave. a base, thereby polymerizing the polymerized monomer on the surface of the base film containing the active site and the inner surface of the pores of the membrane, and simultaneously performing in-situ polymerization to form a copolymer modified layer;

The polymer separation membrane is a flat plate or a hollow fiber membrane made of polypropylene, polyethylene, polysulfone, polyethersulfone or polyvinylidene fluoride.

The polymerizable monomer is a combination of one or a combination of styrene, maleic anhydride, acrylic acid, methacrylic acid or methyl acrylate or methyl methacrylate in any ratio.

The solvent is ethanol, acetone or toluene.

The initiator is benzoyl peroxide.

Preferably, in the present invention, the polymer separation membrane or polymer membrane used is a porous membrane;

In addition, preferably, in the present invention, the initiator is 0.1-0.5% of the mass of the polymerized monomer, preferably Choose 0.1-0.3%.

It is also preferred that the mass ratio of the polymerizable monomer to the polymer separation membrane is from 1 to 6%.

Still preferably, the frequency of the ultrasonic wave described in the step 2) is 30KHZ-50KHZ, more preferably 40KHZ, the power of the ultrasonic wave is 100-500W, the ultrasonic intensity is 600-2000W/m ² , and the liquid temperature is normal temperature to 50 ° C. The treatment time is 1-3 hours.

Still preferably, the ultrasonic wave in the step 3) has a frequency of 30 KHZ-70 KHZ, more preferably 60 KHZ, an ultrasonic power of 100-700 W, an ultrasonic intensity of 600-5000 W/m ² , and an in-situ polymerization under ultrasound. The temperature is 60-80 ° C and the time is 1-6 hours. In the step (1), the ratio of the total mass of the polymerized monomer to the volume of the first organic solvent is 0.05-0.12 g/ml, preferably 0.06-0.08 g/mL.

The ultrasonic in-situ polymerization method of the present invention can provide a polymer separation membrane excellent in separation effect for water treatment by improving the hydrophilicity of the polymer film and increasing the hydrophilic flux.

The method of the present invention will now be described in detail by way of specific examples.

Among them, the model of the ultrasonic instrument used in the following examples is SCQ-9200C, and the manufacturer is Wuxi NVC Ultrasonic Co., Ltd.; wherein the method for testing the porosity of the hollow fiber membrane is by weighing the membrane in a dry and wet state. The porosity is obtained by weight and is expressed by ε.

ε: porosity; W ₁ : wet film weight, g; W ₂ : dry film weight, g;

: density of water, g/cm ³ ; V: apparent volume of the membrane, cm ³ .

Pure water flux measurement method: pure water permeation amount per unit membrane area measured by a conventional instrument at an operating pressure of 0.1 MPa and normal temperature.

Further, in all of the following embodiments, in the step 2), the frequency of the ultrasonic waves used is 40 kHz; in the step 3), the frequency of the ultrasonic waves used is 60 kHz. The output power of the ultrasonic waves used in the step 2) and the step 3) was 500 W, wherein the ultrasonic intensity in the step 2) was 1000 W/m ² and the ultrasonic intensity in the step 3) was 2000 W/m ² . Further, in all of the following examples, the total amount of the polymerized monomers used was 5% by mass relative to the polymer film.

Example 1: A method of modifying a polymer separation membrane by using ultrasonic in-situ polymerization, including the following step:

1) 9.8 g of maleic anhydride, 10.4 g of styrene, 0.05 g of dibenzoyl peroxide were dissolved in 300 ml of acetone to prepare a uniform solution;

2) The polypropylene hollow fiber membrane having a pore diameter of 0.1-0.2 μm is placed in the solution obtained in the step 1) for 24 hours, and then ultrasonicated at room temperature for 1 hour to accelerate the polymerization of the monomer and the initiator in the membrane material. Diffusion, adsorption, so that they are fully adsorbed on the surface of the membrane and in the pores of the membrane;

3) After removing the polypropylene hollow fiber membrane adsorbed with the polymerization monomer and the initiator from the solution, it is immediately placed in 200 ml of ethanol and sonicated at 70 ° C for 5 hours to graft the polymerized monomer to the active site. The base film surface and the inner pore surface, and simultaneously carry out in-situ polymerization to form a copolymer modified layer;

The foregoing steps gave a hollow fiber membrane were tested, a porosity of 65%; at 0.1MPa, which when pure water flux increased from unmodified 140L / m ² · h to 256L / m ² · h.

Embodiment 2 of the present invention: a method for modifying a polymer separation membrane by using ultrasonic in-situ polymerization, comprising the following steps:

1) 9.8 g of maleic anhydride, 10.4 g of styrene, 0.05 g of dibenzoyl peroxide are dissolved in 300 ml of ethanol to prepare a uniform solution;

The foregoing steps gave a hollow fiber membrane were tested, a porosity of 67%; at 0.1MPa, which when pure water flux increased from unmodified 140L / m ² · h to 263L / m ² · h.

Embodiment 3 of the present invention: a method for modifying a polymer separation membrane by using ultrasonic in-situ polymerization, comprising the following steps:

1) dissolving 14.7 g of maleic anhydride, 10.4 g of styrene, and 0.05 g of dibenzoyl peroxide in 300 ml of ethanol to prepare a uniform solution;

2) The polypropylene hollow fiber membrane having a pore diameter of 0.1-0.2 μm is placed in the solution obtained in the step 1) for 24 hours, and then ultrasonicated at 50 ° C for 1 hour to accelerate the polymerization of the monomer and the initiator in the membrane material. Diffusion, adsorption, so that they are fully adsorbed on the surface of the membrane and in the pores of the membrane;

3) After removing the polypropylene hollow fiber membrane adsorbed with the polymerization monomer and the initiator from the solution, it is immediately placed in 200 ml of ethanol and sonicated at 70 ° C for 1 hour to graft the polymerized monomer to the active site. The base film surface and the inner pore surface, and simultaneously carry out in-situ polymerization to form a copolymer modified layer;

The foregoing steps gave a hollow fiber membrane were tested, a porosity of 64%; at 0.1MPa, which when pure water flux increased from unmodified 140L / m ² · h to 355L / m ² · h.

Embodiment 4 of the present invention: a method for modifying a polymer separation membrane by using ultrasonic in-situ polymerization, comprising the following steps:

2) The polypropylene hollow fiber membrane having a pore diameter of 0.1-0.2 μm is placed in the solution obtained in the step 1) for 24 hours, and then ultrasonicated at room temperature for 2 hours to accelerate the polymerization of the monomer and the initiator in the membrane material. Diffusion, adsorption, so that they are fully adsorbed on the surface of the membrane and in the pores of the membrane;

3) After removing the polypropylene hollow fiber membrane adsorbed with the polymerization monomer and the initiator from the solution, it is immediately placed in 200 ml of ethanol and sonicated at 70 ° C for 6 hours to graft the polymerized monomer to the active site. The base film surface and the inner pore surface, and simultaneously carry out in-situ polymerization to form a copolymer modified layer;

The foregoing steps gave a hollow fiber membrane were tested, a porosity of 64%; at 0.1MPa, which when pure water flux increased from unmodified 140L / m ² · h to 363L / m ² · h.

Embodiment 5 of the present invention: a method for modifying a polymer separation membrane by using ultrasonic in-situ polymerization, comprising the following steps:

1) Dissolve 9.8 g of maleic anhydride, 10.4 g of styrene, and 0.05 g of dibenzoyl peroxide in 300 ml. In ethanol, formulated into a uniform solution;

2) The polysulfone hollow fiber membrane is placed in the solution obtained in the step 1) for 24 hours, and then ultrasonicated at room temperature for 2 hours to accelerate the diffusion and adsorption of the polymerization monomer and the initiator in the membrane material, so that they are Fully adsorbed on the surface of the membrane and in the pores of the membrane;

3) After removing the polysulfone hollow fiber membrane adsorbed with the polymerization monomer and the initiator from the solution, it is immediately placed in 200 ml of ethanol and sonicated at 70 ° C for 6 hours to graft the polymerized monomer to the active site. The base film surface and the inner pore surface, and simultaneously carry out in-situ polymerization to form a copolymer modified layer;

The foregoing steps gave a hollow fiber membrane were tested, a porosity of 72%; at 0.1MPa, which when pure water flux increased from unmodified 210L / m ² · h to 354L / m ² · h.

Embodiment 6 of the present invention: A method for modifying a polymer separation membrane by using ultrasonic in-situ polymerization, comprising the following steps:

2) The polysulfone hollow fiber membrane is placed in the solution obtained in the step 1) for 24 hours, and then ultrasonicated at 40 ° C for 2 hours to accelerate the diffusion and adsorption of the polymerization monomer and the initiator in the membrane material. They are fully adsorbed on the surface of the membrane and in the pores of the membrane;

3) The polysulfone hollow fiber membrane to which the polymerization monomer and the initiator were adsorbed was taken out from the solution, immediately placed in 200 ml of ethanol, and sonicated at 80 ° C for 3 hours to graft the polymerized monomer to the active site. The base film surface and the inner pore surface, and simultaneously carry out in-situ polymerization to form a copolymer modified layer;

The foregoing steps gave a hollow fiber membrane were tested, a porosity of 71%; at 0.1MPa, which when pure water flux increased from unmodified 210L / m ² · h to 406L / m ² · h.

Embodiment 7 of the present invention: A method for modifying a polymer separation membrane by using ultrasonic in-situ polymerization, comprising the following steps:

2) The polyethersulfone hollow fiber membrane is placed in the solution obtained in the step 1) for 24 hours, and then ultrasonicated at room temperature for 2 hours to accelerate the diffusion and adsorption of the polymerization monomer and the initiator in the membrane material. They are fully adsorbed on the surface of the membrane and in the pores of the membrane;

3) After removing the polyethersulfone hollow fiber membrane adsorbed with the polymerization monomer and the initiator from the solution, it is immediately placed in 200 ml of ethanol and sonicated at 70 ° C for 6 hours to graft the polymerized monomer to contain the active agent. The base film surface and the inner pore surface of the point are simultaneously subjected to in-situ polymerization to form a copolymer modified layer;

The foregoing steps gave a hollow fiber membrane were tested, a porosity of 89%; at 0.1MPa, which when pure water flux increased from unmodified 183L / m ² · h to 372L / m ² · h.

Embodiment 8 of the present invention: a method for modifying a polymer separation membrane by using ultrasonic in-situ polymerization, comprising the following steps:

2) The polyvinylidene fluoride hollow fiber membrane is immersed in the solution obtained in the step 1) for 24 hours, and then ultrasonicated at room temperature for 2 hours to accelerate the diffusion and adsorption of the polymerization monomer and the initiator in the membrane material. Make them fully adsorbed on the surface of the membrane and in the pores of the membrane;

3) The polyvinylidene fluoride hollow fiber membrane to which the polymerization monomer and the initiator were adsorbed was taken out from the solution, immediately placed in 200 ml of ethanol, and sonicated at 70 ° C for 6 hours to graft the polymerized monomer therein. The base film surface and the inner pore surface of the active point are simultaneously subjected to in-situ polymerization to form a copolymer modified layer;

The foregoing steps gave a hollow fiber membrane were tested, a porosity of 62%; at 0.1MPa, which when pure water flux increased from unmodified 230L / m ² · h to 451L / m ² · h.

Embodiment 9 of the present invention: A method for modifying a polymer separation membrane by using ultrasonic in-situ polymerization, comprising the following steps:

1) dissolving 19.6 g of maleic anhydride, 10.4 g of styrene, and 0.05 g of dibenzoyl peroxide in 300 ml of ethanol to prepare a uniform solution;

3) After removing the polypropylene hollow fiber membrane adsorbed with the polymerization monomer and the initiator from the solution, it is immediately placed in 200 ml of ethanol and sonicated at 70 ° C for 6 hours to graft the polymerized monomer to the active site. The surface of the base film, and simultaneously in situ polymerization to form a copolymer modified layer;

The foregoing steps gave a hollow fiber membrane were tested, a porosity of 63%; at 0.1MPa, which when pure water flux increased from unmodified 140L / m ² · h to 358L / m ² · h.

It is to be understood that the invention is not limited to the specific embodiments described above, and various modifications and changes may be made by those skilled in the art without departing from the scope of the invention.

The above is a further detailed description of the present invention in connection with specific alternative embodiments, and it is not intended that the specific embodiments of the invention are limited to the description. It is to be understood by those skilled in the art that the present invention can be made in the form of a number of simple deductions or substitutions without departing from the inventive concept.

Claims

A method for modifying a polymer separation membrane by ultrasonic in-situ polymerization, which comprises the following steps:

1) dissolving the polymerization monomer and the initiator in an organic solvent to prepare a uniform solution;

2) immersing the polymer separation membrane in the solution obtained in the step 1) for 24 hours, and then performing ultrasonic treatment to accelerate the diffusion and adsorption of the polymerization monomer and the initiator in the membrane material, so that they are sufficiently adsorbed on the surface of the membrane and Inside the membrane pores;

3) After the polymer separation membrane adsorbing the polymerization monomer and the initiator is taken out from the solution, it is immediately placed in an organic solvent, and the cavitation effect of the ultrasonic wave is used to generate radicals of the polymer macromolecule or small molecule, thereby The polymerized monomer is grafted on the surface of the base film containing the active point, and simultaneously polymerized in situ to form a copolymer modified layer;

4) The polymer separation membrane after the in-situ polymerization reaction is taken out and repeatedly washed with ethanol to remove residual oligomers and an excessive amount of the initiator to obtain a finished product.
The method for modifying a polymer separation membrane by ultrasonic in-situ polymerization according to claim 1, wherein the polymer separation membrane is polypropylene, polyethylene, polysulfone, polyethersulfone or polybuturization. Fluoroethylene is a flat plate or hollow fiber membrane of a material.
The method for modifying a polymer separation membrane by ultrasonic in-situ polymerization according to claim 1, wherein the polymerized monomer is styrene, maleic anhydride, acrylic acid, methacrylic acid or methacrylic acid. One or a combination of the two of the methyl esters is combined in any ratio.
The method for modifying a polymer separation membrane by ultrasonic in-situ polymerization according to claim 1, wherein the organic solvent is ethanol, acetone or toluene.
The method for modifying a polymer separation membrane by ultrasonic in-situ polymerization according to claim 1, wherein the initiator is benzoyl peroxide.
The method for modifying a polymer separation membrane by ultrasonic in-situ polymerization according to claim 1, 3 or 5, characterized in that the initiator is from 0.1 to 0.5% by mass of the polymerized monomer.
A method for modifying a polymer film by ultrasonic in-situ polymerization, comprising: the following steps:

1) dissolving the polymerizable monomer and the initiator in a first organic solvent to prepare a uniform solution;

2) immersing the polymer film in the solution obtained in the step 1) for more than 24 hours, and then performing sonication to diffuse and adsorb the polymerizable monomer and the initiator in the film material and adsorb into the film surface and/or the pores of the film;

3) After the polymer film adsorbing the polymerization monomer and the initiator is taken out from the solution, it is immediately placed in the first organic solvent, and the polymerized monomer is grafted on the surface of the film containing the active site by the cavitation effect of the ultrasonic wave. And/or in the pores of the membrane, and simultaneously in situ polymerization to form a copolymer modified layer;

4) The polymer separation membrane after the in-situ polymerization reaction is taken out and rinsed with a second organic solvent to obtain a polymer film modified product.
The method for modifying a polymer film by ultrasonic in-situ polymerization according to claim 7, wherein the polymer film is polypropylene, polyethylene, polysulfone, polyethersulfone or polybuturization. Fluoroethylene is a flat plate or hollow fiber membrane of a material.
The method for modifying a polymer separation membrane by ultrasonic in-situ polymerization according to claim 7, wherein the polymerized monomer is styrene, maleic anhydride, acrylic acid, methacrylic acid or methyl acrylate Or a combination of one or two of methyl methacrylate in any ratio.
The method for modifying a polymer separation membrane by ultrasonic in-situ polymerization according to claim 7, wherein the first organic solvent and the second organic solvent are each independently obtained from ethanol or acetone. Toluene.
The method for modifying a polymer separation membrane by ultrasonic in-situ polymerization according to claim 7, wherein the initiator is benzoyl peroxide.
The method for modifying a polymer film by ultrasonic in-situ polymerization according to any one of claims 7 to 11, characterized in that the initiator is 0.1-0.5% by mass of the polymerized monomer, preferably 0.1- 0.3%.
The method for modifying a polymer film by ultrasonic in-situ polymerization according to any one of claims 7 to 12, characterized in that the total mass of the polymerized monomer is from 1 to 6% by mass relative to the mass of the polymer film. .
The method for modifying a polymer film by ultrasonic in-situ polymerization according to any one of claims 7 to 13, characterized in that in the step (2), the temperature is from room temperature to 50 ° C; preferably, the ultrasonic wave The frequency is 30 KHZ-50 KHZ; more preferably, the ultrasonic power is 100-500 W; more preferably, the ultrasonic intensity is 600-2000 W/m 2 ; more preferably, the ultrasonic time is 1-3 h.
The method for modifying a polymer film by ultrasonic in-situ polymerization according to any one of claims 7-14, wherein in the step (3), the temperature is from 60 ° C to 80 ° C; preferably, The frequency of the ultrasonic waves is 30 kHz to 70 kHz; more preferably, the ultrasonic power is 100 to 700 W; more preferably, the ultrasonic intensity is 600 to 5000 W/m 2 ; more preferably, the ultrasonic time is 1-6 h.
The method for modifying a polymer film by ultrasonic in-situ polymerization according to any one of claims 7 to 15, wherein in step (1), the total mass of the polymerized monomer and the volume of the first organic solvent The ratio is: 0.05-0.12 g/ml, preferably 0.06-0.08 g/ml.
A polymer separation membrane obtained by the method according to any one of claims 1 to 16, which has a porosity of 62 to 89% and a pure water flux of 256 L/m 2 h or more.