CN100337730C - Preparation method of structurally symmetrical polyethersulfone hydrophilic microporous membrane - Google Patents

Abstract

The invention relates to a preparation method of a polymer microporous membrane, and aims to provide a preparation method of a symmetrical polyethersulfone hydrophilic microfiltration flat membrane. The method provided by the invention comprises the steps of preparing polyethersulfone microporous membrane casting solution, scraping a nascent liquid membrane on a flat carrier, partial gelation in the first coagulation bath, complete gelation in the second coagulation bath and water washing. The polyethersulfone microporous membrane prepared by the method provided by the invention has structural symmetry, hydrophilicity and temperature resistance, and the pore diameter can be adjusted between 0.5 and 10 μm, and is especially suitable as a medical membrane material.

Description

Preparation method of structurally symmetrical polyethersulfone hydrophilic microporous membrane

technical field

The invention relates to a preparation method of a polymer microporous membrane, in particular to a preparation method of a symmetrical polyethersulfone hydrophilic microfiltration flat membrane.

Background technique

Membrane separation technology is an emerging separation technology, which has the advantages of high efficiency, low energy consumption, and easy integration with other technologies, representing the development direction of separation technology. The core of membrane separation technology is the membrane with separation function. According to the pore size from small to large, separation membranes are divided into reverse osmosis membranes, nanofiltration membranes, ultrafiltration membranes and microfiltration membranes, among which microporous membranes with a pore size of 0.1 μm or more (microfiltration membranes) are the most widely used. , the most widely used film variety. Because microporous membrane filtration technology has the advantages of simple, fast, high-efficiency and energy-saving, it has great application significance in the fields of petroleum, chemical industry, medicine/medical treatment, chemical industry, electronics, energy and environmental protection. For decades, microporous membrane filtration technology has gradually replaced or improved many traditional separation and purification processes, such as: replacing the original cardboard fine filter in beer clarification filtration, improving the clarity of beer; It replaces the original cotton cloth and activated carbon filled tower to ensure the sterilization effect; it replaces the traditional distillation technology in pharmaceutical and chemical industry, and realizes concentration and separation at low temperature; the technology combined with bioreactor to realize microbial separation is used for fermentation and Wastewater treatment; used as lithium-ion battery diaphragm; used for infusion treatment of traditional Chinese medicine liquid filtration, etc.

From the perspective of material types, there are two types of microporous membranes: inorganic membranes and organic polymer membranes. The former is characterized by temperature resistance, good hydrophilicity, and less pollution, but the preparation cost is high; the latter is mainly made of nylon, Cellulose, polysulfone, polyvinylidene fluoride, polyester, etc. are characterized by low production cost, but they have problems of poor temperature resistance, poor hydrophilicity or both. At the same time, most organic polymer microporous membranes are prepared by the phase inversion method. The characteristics of the existing phase inversion method lead to the large pores in the membrane. Symmetry is not easy to control, and most membranes are asymmetric membranes with different pore sizes on both sides of the membrane, which limits some important applications of organic polymer microporous membranes.

Polyether sulfone (PES), also known as polyphenylene ether sulfone or polyaryl ether sulfone, has the rigidity of benzene ring, the flexibility of ether group and the large conjugated system formed by sulfone group and the whole structural unit in the molecular chain. It has high strength, Temperature resistance (can be used above 180°C), flame resistance, radiation resistance, acid resistance, oxidation resistance, solvent resistance, biocompatibility, etc., is a polymer material with excellent comprehensive properties. In recent years, it has also become a separation membrane material. More and more attention has been paid. The preparation method of polyethersulfone separation membrane is mainly the phase inversion method. Existing reports include: Chinese patent 000125306 discloses a preparation method of sulfonated polyethersulfone nanofiltration membrane, and the obtained molecular weight cut-off of the membrane is 300-1000; Manufacturing method; Chinese patent 03130557.1 discloses the preparation method of polyethersulfone hollow fiber ultrafiltration or dialysis membrane; US patents 5,869,174, 4,629,563 and 4,774,039 disclose the method of preparing highly asymmetric polyethersulfone membrane. From a comprehensive point of view, these existing reports have three outstanding features. First, the methods used are all phase inversion methods of one-step gelation to complete the solidification of the liquid film, that is, starting from the nascent liquid film and passing through a gel bath once. Solid polyethersulfone membranes are obtained by gelation; second, these membranes have an asymmetric structure, one side of the membrane has a dense skin layer, and the other side has a macroporous structure, which is mostly used for super-rate membranes and dialysis membranes; It is that the pore channel in the membrane is mainly a finger-like pore structure. Recently, U.S. Patent No. 6,056,903 announced the preparation method of polyethersulfone microporous membrane with structural symmetry, but it uses a mixture solution of fatty alcohol and water with 2 to 20 carbons as the only coagulation bath, and the core is still a primary gelation solidification. Phase inversion method, and the obtained polyethersulfone membrane is still hydrophobic. In order to meet the needs of membrane separation technology in the fields of separation and purification of water treatment, pharmaceuticals, medical precision infusion sets, and medicinal liquid filtration, the inventors have obtained a symmetrical, hydrophilic polymer based on systematic experiments and research results. Secondary gel phase inversion method for ethersulfone microporous membranes.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art, providing a kind of preparation method of structurally symmetrical hydrophilic polyethersulfone microporous membrane, comprising the following steps:

(1) Mix polyethersulfone, hydrophilic agent, thickener and solvent, stir at 20-100°C for 10-30 hours to dissolve, then slowly add additives to the solution, and then continue stirring at the same temperature for 10-30 hours 30 hours; cooled to room temperature, degassing in vacuum for 1 to 30 hours to obtain a casting solution for preparing polyethersulfone microporous membrane; each component composition and the mass percentage of each component in the casting solution are:

Polyethersulfone: molecular weight 2×10 ⁴ ~5×10 ⁵ , 8~18%;

Hydrophilic agent: sulfonated polyethersulfone with a sulfonation degree of 5-10%, 0.5-5%;

Thickener: at least one of polyvinylpyrrolidone or polyethylene glycol with a molecular weight of 2×10 ³ to 2×10 ⁶ , 1-7%;

Solvent: any one of N,N'-dimethylacetamide, N,N'-dimethylformamide or N-methylpyrrolidone, 65-90%;

Additive: any one of water, glycerin, ethylene glycol or diethylene glycol ether, 1-10%;

The sum of the contents of the above components is equal to 100%;

(2) Scrape the casting solution at 10-70°C on the flat carrier to form a 100-600 μm thick primary liquid film, and stay in the air with a temperature of 10-40°C and a relative humidity of 40-90% for 5-60 Second;

(3) Immerse the nascent liquid film on the flat carrier in the first coagulation bath at 10-60°C for 5-60 seconds for partial gelation; the first coagulation bath is a mixture of two components, each group The composition and mass concentration of the points are:

The first component: any one of N, N'-dimethylacetamide, N, N'-dimethylformamide or N-methylpyrrolidone is the same solvent as in the casting solution, 50% to 90%;

The second component: any one of water or ethylene glycol, 10-50%;

(4) Immerse the partially gelled liquid film in a second coagulation bath at 10-50°C for 50-180 seconds to fully gel to obtain a solid film; the composition and mass concentration of each component of the second coagulation bath are:

The first component: any one of N,N'-dimethylacetamide, N,N'-dimethylformamide or N-methylpyrrolidone is the same solvent as in the casting solution, 0-30%;

The second component: surfactant sodium dodecylsulfonate, 0-0.05%;

The third component: water, 70-100%;

(5) The fully gelled solid polyethersulfone membrane is soaked in water at 10-60°C for 24-72 hours and then dried.

As an improvement of the present invention, the gelled solid polyethersulfone membrane further includes a step of soaking in 0.2-0.6 wt% sodium hypochlorite aqueous solution at 10-60°C for 24-72 hours before soaking and washing.

As an improvement of the present invention, the concentration of the aqueous solution of sodium hypochlorite is 0.3-0.5wt%, the soaking temperature is 40-50°C, and the soaking time is 40-50 hours; the temperature of soaking and washing is 20-50°C, and the time is 40-50°C. 50 hours; the drying temperature is controlled below 80°C.

As an improvement of the present invention, the composition of the first coagulation bath is as follows: the first component is any solvent of N, N'-dimethylacetamide or N, N'-dimethylformamide, Mixed solution with any one of the second component water or ethylene glycol; the mass content of the first component solvent is 65% to 85%; the temperature of the first coagulation bath is 20 to 40°C; The time for partial gelation in the coagulation bath is 10 to 40 seconds.

As an improvement of the present invention, the composition of the second coagulation bath is a mixed solution of N, N'-dimethylacetamide, sodium dodecylsulfonate and water, wherein N, N'-dimethyl The mass content of acetamide is 10-20%; the mass content of sodium dodecylsulfonate is 0.02-0.03%; the temperature of the second coagulation bath is 20-40°C; fully gelled in the second coagulation bath The time is 80-120 seconds.

As an improvement of the present invention, the components and mass concentrations of the prepared casting solution are:

Polyethersulfone concentration: 12-16%;

Concentration of sulfonated polyethersulfone: 1-3%;

Thickener: polyvinylpyrrolidone with a molecular weight of 5×10 ⁴ to 2×10 ⁵ , with a concentration of 3 to 6%;

Solvent: N, N'-dimethylacetamide, concentration 75-85%;

Additive: water or diethylene glycol ether, concentration 2-6%;

The sum of the contents of the above components is equal to 100%.

As an improvement of the present invention, the temperature of the casting solution is 20-40°C; the flat plate carrier is a stainless steel plate; when staying in the air, the air temperature is 20-30°C, and the relative humidity is 55-85%. The residence time is 10 to 35 seconds.

As an improvement of the present invention, after the casting solution is prepared, a step of filtering the casting solution is also included.

The beneficial effects of the present invention are:

Different from the previous method for preparing polyethersulfone membrane by primary gelation, the present invention provides a secondary gel phase inversion method to obtain a polyethersulfone microporous membrane with a symmetrical structure, which solves the problem of the preparation of the existing phase inversion method. The microporous membrane is an asymmetric structure, and the cortex affects the flux.

Moreover, a kind of secondary gel phase inversion method provided in the present invention obtains a spongy interconnected pore structure inside the polyethersulfone microporous membrane, which has a high porosity while still having relatively high strength, which is different from the existing The polyethersulfone microporous membrane prepared by the phase inversion method has a finger-like pore structure inside, and its strength is low.

Also, in the method provided by the present invention, by adjusting the composition and temperature of the casting solution, the first coagulation bath and the second coagulation bath, and the residence time of the nascent liquid film in the air, it is possible to prepare a film with a pore size of 0.5-10 μm. polyethersulfone microporous membrane.

In addition, in the method provided by the present invention, the sulfonated polyethersulfone is used as the hydrophilic agent to blend with polyethersulfone in the casting solution, and the hydrophilization and hydrophilicity of the polyethersulfone microporous membrane can be realized simultaneously during the preparation process. The modification efficiency is high and the cost is low; at the same time, since the sulfonated polyethersulfone is a water-insoluble polymer, the hydrophilicity of the polyethersulfone microporous membrane is permanent.

In addition, in the method provided by the present invention, after the solid polyethersulfone membrane is treated with an aqueous solution of sodium hypochlorite, the flux of the membrane can be further improved, and the pore structure does not change significantly.

In summary, the polyethersulfone microporous membrane prepared by the method provided by the present invention has a symmetrical structure, hydrophilicity and temperature resistance, and the pore diameter can be adjusted between 0.5 and 10 μm, and is especially suitable for use as a medical membrane material.

Detailed ways

A method for preparing a structurally symmetrical hydrophilic polyethersulfone microporous membrane provided by the present invention consists of five steps, and the specific implementation of each step is as follows:

1) Preparation of casting solution: mix polyethersulfone, sulfonated polyethersulfone, thickener, additive and solvent, stir at 20-100°C for 20-50 hours to dissolve; cool to room temperature, defoam in vacuum for 1 After ~30 hours, the casting solution for preparing the polyethersulfone microporous membrane was obtained.

The specifications and mass concentrations of the components in the casting solution are: Polyethersulfone (PES): sulfonated polyether with a molecular weight of 2×10 ⁴ to 5×10 ⁵ , 8 to 18%; a sulfonation degree of 5-10% Sulfone (SPES): 0.5-5%; thickener: polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG) or a mixture of the two with a molecular weight of 2×10 ³ to 2× ¹⁰ 6 , 1-7% ; Additives: water, glycerin, ethylene glycol or diethylene glycol ether, 1 to 10%; Solvents: N, N'-dimethylacetamide (DMAC), N, N'-dimethylformamide (DMF ) or N-methylpyrrolidone (NMP), 65-90%.

The best conditions are: PES concentration: 12-16%; SPES concentration: 1-3%; thickener: PVP with a molecular weight of 5×10 ⁴ ～2×10 ⁵ , concentration 3-6%; solvent: DMAC, Concentration 75-85%; additive: water or diethylene glycol ether, concentration 2-6%.

The temperature and stirring time for preparing the casting solution shall be subject to the sufficient uniformity of the casting solution. The vacuum degassing time shall be subject to fully removing the air in the casting solution.

2) Scrape the primary liquid film and pre-evaporate in the air: Scrape the casting solution at 10-70°C on a flat carrier such as glass, stainless steel or polyester to form a primary liquid film with a thickness of 100-600 μm, and heat it at a temperature of Stay in the air at 10-40°C and relative humidity of 40-90% for 5-60 seconds.

The best conditions are: casting solution: 20-40°C; carrier: stainless steel; air temperature: 20-30°C; relative air humidity: 55-85%; residence time: 5-35 seconds.

Among them, the thickness of the primary liquid film depends on the thickness of the final solid polyethersulfone microporous membrane, and is controlled by the depth of the scraper edge. The optimal thickness of the primary liquid film is 200-400 μm. In order to prevent the influence of large insoluble particles in the casting solution on the uniformity of the polyethersulfone membrane and eliminate pinholes, the membrane solution needs to be properly filtered.

3) The first gelation: the nascent liquid film on the carrier that has been suspended in the air is immersed in the first coagulation bath at 10-60° C. for 5-60 seconds to perform partial gelation. The composition of the coagulation bath is: a mixed liquid composed of solvent DMAC, DMF or NMP and the second component of water or ethylene glycol, wherein the mass content of the solvent is 50-90%.

Optimum conditions: solvent DMAC or DMF, 65%-85%; second component: ethylene glycol or water: 15-35%; temperature: 20-40°C; time: 10-40 seconds.

4. The second gelation: The partially gelled nascent liquid film on the carrier is immersed in the second coagulation bath at 10-50°C for 50-180 seconds to fully gel to obtain solid polyethersulfone membrane. Second coagulation bath composition: a mixture of solvent DMAC, DMF or NMP, water, and surfactant sodium dodecylsulfonate (TOSN _a ). Wherein the concentration of each component: solvent: 0-30%; water: 70-100%; sodium dodecylsulfonate: 0-0.05%.

Optimum conditions: solvent: DMAC, 10-20%; water: 80-90%; sodium dodecylsulfonate: 0.02-0.03% temperature 20-40°C; immersion time: 80-120 seconds.

5) Post-treatment of solid-state membrane: The polyethersulfone membrane that has been gelled for the second time, completely solidified and peeled off from the carrier is soaked in 0.2-0.6wt% sodium hypochlorite (NaClO) aqueous solution at 10-60°C for 24-24～ Soak in water at 10-60°C for 72 hours, wash for 24-72, and then dry. The best conditions are: soaking in 40-50°C and 0.3-0.5wt% sodium hypochlorite aqueous solution for 40-50 hours; soaking in 40-50°C water for 40-50 hours; drying conditions are not limited, but the temperature is below 80°C.

In the preparation method, by adjusting the composition and temperature of the casting solution, the first coagulation bath and the second coagulation bath, and the residence time of the nascent liquid film in the air, polyethersulfone microstructures with different pore sizes can be prepared. Porous film. An important method to control the pore size of the membrane is: when preparing a polyethersulfone microporous membrane with a large pore size, the content of thickeners and additives in the casting solution; the required temperature of the casting solution is increased, and the temperature and humidity of the scraping air are lower High, or the initial liquid film stays in the air for a long time; the first and second coagulation baths have high solvent content and high temperature.

When using the thickener PVP, it needs to be soaked in sodium hypochlorite aqueous solution for post-treatment. Along with the raising of PVP content in the film-casting liquid, suitably improve the concentration and the temperature of sodium hypochlorite aqueous solution high, prolong the treatment time long; When PVP is not used as the thickener of the casting solution, it is not necessary to use sodium hypochlorite aqueous solution in the post-treatment of the solid polyethersulfone membrane.

The following is an example of preparation of a hydrophilic symmetrical structure polyethersulfone microporous membrane. The implementation conditions of the examples are listed in the list, and the implementation steps of all the examples are the same as the aforementioned implementation steps.

The various implementation conditions of embodiment 1 are as shown in table 1:

Table I Casting solution Composition and mass content (%) Stirring conditions vacuum degassing PES SPES PEG DMAC water 50℃, 24h 20℃, 5h 17.0 1.5 2.5 77.0 2.0 Scratch film Casting solution temperature carrier Depth of scraper edge air environment dwell time 20°C Stainless steel 300μm 20℃, relative humidity 65% 5 seconds first gelation Mass composition of the first coagulation bath temperature(℃) time (seconds) DMAc55%, water 45% 20 5 second gelation Mass composition of the second coagulation bath temperature(℃) time (seconds) water 100% 20 50 Post-processing Sodium hypochlorite aqueous solution immersion water immersion dry / 20℃, 72h Air dry for 24 hours

Main raw materials: PES: RADEL ^® A100, Solvay Advanced Polymers, LLC); SPES: sulfonation degree 6.5%, Changchun Jida High-tech Materials Co., Ltd.; PEG: 20000, China Pharmaceutical Group Shanghai Chemical Reagent Company; DMAc: Shanghai Jingwei Chemical Co., Ltd. company.

The various implementation conditions of embodiment 2 are as shown in table two:

Table II Casting solution Composition and mass content (%) Stirring conditions vacuum degassing PES SPES pvp DMAC water 60℃, 36h 25℃, 5h 15.5 3.0 3.5 75.0 3.0 Scratch film Casting solution temperature carrier Depth of scraper edge air environment dwell time 25°C Glass 250μm 25℃, relative humidity 70% 10 seconds first gelation Mass composition of the first coagulation bath temperature(℃) time (seconds) DMAc65%, water 35% 30 20 second gelation Mass composition of the second coagulation bath temperature(℃) time (seconds) TOSN _a 0.01%, water 99.99% 30 90 Post-processing Soak in NaClO aqueous solution water immersion dry NaClO concentration: 0.2%, 20°C, 48h 30℃, 48h Air dry for 24 hours

Wherein: PVP, K60, China Pharmaceutical Group Shanghai Chemical Reagent Company; Other raw materials are as shown in Table 3 with the implementation conditions of Example 1 and Example 3:

Table three Casting solution Composition and mass content (%)) Stirring conditions vacuum degassing PES SPES PVP-K90 DMAC Ethylene glycol 55℃, 36h 25℃, 15h 12.5 4.0 3.5 75.0 5.0 Scratch film Casting solution temperature carrier Depth of scraper edge air environment dwell time 30℃ Stainless steel 250μm 25℃, relative humidity 75% 20 seconds first gelation Mass composition of the first coagulation bath temperature(℃) time (seconds) DMAc78%, water 22% 35 30 second gelation Mass composition of the second coagulation bath temperature(℃) time (seconds) TOSN _a 0.02%, water 89.98%, DMAC10% 40 90 Post-processing Soak in NaClO aqueous solution water immersion dry NaClO concentration: 0.4%, 45°C, 48h 45℃, 48h Air dry for 24 hours

Wherein: PVP, K90, China Pharmaceutical Group Shanghai Chemical Reagent Company; other raw materials are the same as in Example 1.

The various implementation conditions of embodiment 4 are as shown in table four:

Table four Casting solution Composition and mass content (%) Stirring conditions vacuum degassing PES SPES PVP-K90 DMAC water 60℃, 48h 25℃, 20h 12.5 2.0 4.5 77.0 3.0 Scratch film Casting solution temperature carrier Depth of scraper edge air environment dwell time 35°C Stainless steel 300μm 25℃, relative humidity 80% 30 seconds first gelation Mass composition of the first coagulation bath temperature(℃) time (seconds) DMAc82%, water 22% 40 30 second gelation Mass composition of the second coagulation bath temperature(℃) time (seconds) TOSN _a 0.04%, water 69.96%, DMAc 30% 40 120 Post-processing Soak in NaClO aqueous solution water immersion dry / 45℃, 72h Air dry for 24 hours

Raw material is with embodiment 3.

The various implementation conditions of embodiment 5 are as shown in table five:

Table five Casting solution Composition and mass content (%) Stirring conditions vacuum degassing PES SPES PVP-K90 DMAC water 60℃, 48h 25℃, 20h 12.5 1.0 4.5 79.0 3 Scratch film Casting solution temperature carrier Depth of scraper edge air environment dwell time 35°C Stainless steel 300μm 25℃, relative humidity 80% 30 seconds first gelation Mass composition of the first coagulation bath temperature(℃) time (seconds) DMAc90%, water 10% 40 30

Second gelation The mass composition of the second coagulation bath Temperature (°C) time (seconds) TOSN _a 0.04%, water 69.96%, DMAc 30% 40 120 Post-processing Soak in NaClO aqueous solution Soak in water dry NaClO concentration: 0.5%, 45°C, 40h 45℃, 24h After drying, dry at 65°C for 10 hours

Raw material is with embodiment 4.

The various implementation conditions of embodiment 6 are as shown in table six:

Table six Casting solution Composition and mass content (%) Stirring conditions vacuum degassing PES SPES PVP-K90 DMAC water 60℃, 48h 10℃, 24h 14.5 0.5 3.5 79.0 2.5 Scratch film Casting solution temperature carrier Depth of scraper edge air environment dwell time 10°C Stainless steel 600μm 10℃, relative humidity 50% 60 seconds first gelation Mass composition of the first coagulation bath temperature(℃) time (seconds) DMAc50%, water 50% 40 60 second gelation Mass composition of the second coagulation bath temperature(℃) time (seconds) TOSN _a 0.06%, water 69.94%, DMAc 30% 40 120 Post-processing Soak in NaClO aqueous solution water immersion dry / 10℃, 72h Air dry for 24 hours

Raw material is with embodiment 5.

The various implementation conditions of embodiment 7 are as shown in table seven:

Table Seven Casting solution Composition and mass content (%) Stirring conditions vacuum degassing PES SPES pvp DMAC water 60℃, 48h 25℃, 5h 9.0 0.5 2.0 87.5 1.0 Scratch film Casting solution temperature carrier Depth of scraper edge air environment dwell time 70°C Glass 100μm 20℃, relative humidity 70% 55 seconds

The first gelation The mass composition of the first coagulation bath Temperature (°C) time (seconds) DMAc25%, water 75% 25 20 Second gelation The mass composition of the second coagulation bath Temperature (°C) time (seconds) TOSN _a 0.05%, water 99.95% 45 180 Post-processing Soak in NaClO aqueous solution Soak in water dry NaClO concentration: 0.6%, 20°C, 24h 60℃, 48h Dry in the air for 24 hours

Raw material is with embodiment 2

The various implementation conditions of embodiment 8 are as shown in table eight:

table eight Casting solution Composition and content (g) Stirring conditions vacuum degassing PES SPES PVP-K90 DMAC glycerin 60℃, 48h 15℃, 20h 13.5 5.0 7.0 65.5 10.0 Scratch film Casting solution temperature carrier Depth of scraper edge air environment dwell time 15°C Stainless steel 300μm 15℃, relative humidity 60% 10 seconds first gelation Mass composition of the first coagulation bath temperature(℃) time (seconds) DMAc55%, water 45% 15 30 second gelation Mass composition of the second coagulation bath temperature(℃) time (seconds) Water 70%, DMAc30% 15 180 Post-processing Soak in NaClO aqueous solution water immersion dry / 15℃, 72h Air dry for 24 hours

Raw material is with embodiment 4.

The various implementation conditions of embodiment 9 are as shown in table nine:

Table nine Casting solution Composition and mass content (%) Stirring conditions vacuum degassing PES SPES PVP-K90 DMF Diethylene glycol ether 55℃, 36h 25℃, 15h 11.5 1.0 6.5 79.5 3.0

Scratch film Casting liquid temperature carrier Depth of scraper edge air environment Dwell time 70℃ Stainless steel 250μm 25℃, relative humidity 85% 50 seconds The first gelation The mass composition of the first coagulation bath Temperature (°C) time (seconds) DMAc85%, water 15% 55 40 Second gelation The mass composition of the second coagulation bath Temperature (°C) time (seconds) TOSN _a 0.05%, water 14.95%, DMAc 85% 40 150 Post-processing Soak in NaClO aqueous solution Soak in water dry NaClO concentration: 0.4%, 45°C, 48h 45℃, 48h Dry in the air for 24 hours

Other raw materials are with embodiment 3.

The structure and performance of polyethersulfone microporous membrane samples in each embodiment are shown in Table 10, wherein:

Water flux test set: use a sample with a diameter of 10cm to test under the static pressure of a water column of 1m;

Determination of membrane pore size and porosity: mercury porosimetry (instrument: DEMO9500 mercury porosimeter, Micromecritics Instrument Corp, USA)

table ten sample number Average pore size (μm) Porosity (%) Film thickness (μm) 1m water column static pressure water flux L/(m ² ·h) Example 1 1.05 63.5 56 986 Example 2 2.65 68.3 63 2300 Example 3 5.12 77.4 70 8588 Example 4 8.86 75.8 77 14057 Example 5 9.03 76.6 74 15783 Example 6 0.52 61.5 214 395 Example 7 4.85 67.3 34 4340

Example 8 2.07 59.3 61 1930 Example 9 10.23 76.6 75 17250

Finally, it should also be noted that what is listed above are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All deformations that can be directly derived or associated by those skilled in the art from the content disclosed in the present invention should be considered as the protection scope of the present invention.

Claims (8)

1, a kind of preparation method of symmetrical configuration hydrophilic polyethersulfone microporous barrier may further comprise the steps:

(1), after 20～100 ℃ stirring was dissolved in 10～30 hours down, in solution, slowly drips additive, again in the lasting down stirring of uniform temp 10～30 hours with polyether sulfone, hydrophilizing agent, thickener and solvent; Cool to room temperature, deaeration is 1～30 hour in a vacuum, obtains being used to prepare the casting solution of microporous membrane of polyethersulfone; Each component composition and each component mass percent in casting solution is:

Polyether sulfone: molecular weight is 2 * 10 ⁴～5 * 10 ⁵, 8～18%;

Hydrophilizing agent: sulfonation degree is 5～10% sulfonated polyether sulfone, 0.5～5%;

Thickener: molecular weight is 2 * 10 ³～2 * 10 ⁶Polyvinylpyrrolidone or polyethylene glycol wherein at least a, 1～7%;

Solvent: N, N '-dimethylacetylamide, N, N '-dimethyl formamide or N-methyl pyrrolidone wherein any one, 65～90%;

Additive: water, glycerine, ethylene glycol or diethylene glycol ether wherein any one, 1～10%;

More than each constituent content sum equal 100%;

(2) 10～70 ℃ casting solution is spread to the thick nascent liquid film of 100～600 μ m on dull and stereotyped carrier, and be that 10～40 ℃, relative humidity are to stop 5～60 seconds in 40～90% the air in temperature;

(3) the nascent liquid film on the dull and stereotyped carrier is immersed in 10～60 ℃ first coagulating bath and carry out partial gelization in 5～60 seconds; Described first coagulating bath is the mixed liquid that two kinds of components are formed, and the composition of each component and mass concentration are:

First component: N, N '-dimethylacetylamide, N, N '-dimethyl formamide or N-methyl pyrrolidone wherein any one with casting solution in identical solvent, 50～90%;

Second component: water or ethylene glycol wherein any one, 10～50%;

(4) liquid film of partial gelization is immersed 10～50 ℃ second coagulating bath abundant gelation in 50～180 seconds and obtain solid film; The composition of described second each component of coagulating bath and mass concentration are:

First component: N, N '-dimethylacetylamide, N, N '-dimethyl formamide or N-methyl pyrrolidone wherein any one with casting solution in identical solvent, 0～30%;

Second component: surfactant dodecyl sodium sulfate, 0～0.05%;

The 3rd component: water, 70～100%;

(5) the solid-state poly (ether sulfone) film after the abundant gelation is dry after 24～72 hours through 10～60 ℃ soaking and water washing.

2, according to the preparation method of the described microporous membrane of polyethersulfone of claim 1, it is characterized in that, solid-state poly (ether sulfone) film after the described gelation also comprises the step that the 0.2～0.6wt% aqueous sodium hypochlorite solution that uses 10～60 ℃ soaked 24～72 hours before soaking and water washing.

According to the preparation method of the described microporous membrane of polyethersulfone of claim 2, it is characterized in that 3, described aqueous sodium hypochlorite solution concentration is 0.3～0.5wt%, soaking temperature is 40～50 ℃, and soak time is 40～50 hours; The temperature of soaking and water washing is 20～50 ℃, and the time is 40～50 hours; Baking temperature is controlled at below 80 ℃.

4, according to the preparation method of the described microporous membrane of polyethersulfone of claim 1, it is characterized in that, consisting of of described first coagulating bath: first component is N, N '-dimethylacetylamide or N, N '-dimethyl formamide is any one solvent wherein, with the second component water or the ethylene glycol mixed liquor of any one composition wherein; Wherein the mass content of first component solvent is 65%～85%; The temperature of first coagulating bath is 20～40 ℃; The time of part gelation is 10～40 seconds in first coagulating bath.

5, according to the preparation method of the described microporous membrane of polyethersulfone of claim 1, it is characterized in that, described second coagulating bath consist of N, the mixed liquor that N '-dimethylacetylamide, dodecyl sodium sulfate and water are formed, N wherein, the mass content of N '-dimethylacetylamide is 10～20%; The mass content of dodecyl sodium sulfate is 0.02～0.03%; The temperature of second coagulating bath is 20～40 ℃; Fully the time of gelation is 80～120 seconds in second coagulating bath.

According to the preparation method of the described microporous membrane of polyethersulfone of claim 1, it is characterized in that 6, each the component composition and the mass concentration of described preparation casting solution are:

Polyether sulfone concentration: 12～16%;

Sulfonated polyether sulfone concentration: 1～3%;

Thickener: molecular weight 5 * 10 ⁴～2 * 10 ⁵Polyvinylpyrrolidone, concentration 3～6%;

Solvent: N, N '-dimethylacetylamide, concentration 75～85%;

Additive: water or diethylene glycol ether, concentration 2-6%;

More than each constituent content sum equal 100%.

According to the preparation method of the described microporous membrane of polyethersulfone of claim 1, it is characterized in that 7, described casting solution temperature is 20～40 ℃; Described dull and stereotyped carrier is a corrosion resistant plate; When stopping in air, air themperature is 20～30 ℃, and relative humidity is 55～85%, and the time of staying is 10～35 seconds.

8, according to the preparation method of the described microporous membrane of polyethersulfone of claim 1, it is characterized in that, after the described casting solution preparation, also comprise the step that casting solution is filtered.