Preparation method of anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization

Abstract

The invention provides a preparation method of an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization, which comprises the following steps: step 1, dissolving PES (Polyether Sulfonate) and PVP (Polyvinyl Pyrrolidone) in a solvent, and mixing to form an initial solution; 2, adding SBMA and NaSS monomers into the initial solution, and mixing to form a uniform solution; 3, adding a cross-linking agent and an initiator into the uniform solution, and stirring to form a uniform membrane casting solution; 4, defoaming the membrane casting solution; 5, preparing a hollow fiber membrane; wherein free radicals are generated when the initiator is decomposed in the step 3, and double bonds of the SBMA and the NaSS are initiated to be opened to form monomer free radicals; the cross-linking agent forms a covalent bond between SBMA and NaSS through a bonding effect so as to construct a cross-linked network. A new additive can be introduced in the preparation process of the hollow fiber membrane, and the water flux, the long-term stability and the biocompatibility of the membrane are synchronously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of hemodialysis membrane preparation, in particular to a method for preparing an anti-pollution and anti-coagulation blood membrane based on in-situ micro-crosslinking-polymerization. Background Art

[0002] Hemodialysis, as an extracorporeal blood purification technique, removes metabolic waste accumulated in patients with end-stage renal disease (ESRD) through semipermeable membrane-mediated diffusion and convection. It is a core treatment for acute and chronic renal failure. Polysulfone (PSU) and polyethersulfone (PES) have become the mainstream membrane materials for hemodialysis membranes due to their excellent chemical stability, mechanical strength, and processing properties. For example, patent application CN104190271B discloses a polyethersulfone / alginate composite hollow fiber membrane and its preparation method, which can be used to prepare composite hollow fiber membranes that are resistant to steam sterilization, have high hydrophilicity, and ion adsorption.

[0003] However, the inherent hydrophobicity of polysulfone (PSU) and polyethersulfone (PES) membranes easily activates the complement system and promotes platelet adhesion, triggering the release of inflammatory factors and the coagulation cascade, reducing biocompatibility. Furthermore, the gradual elution of additives (such as polyvinylpyrrolidone) causes the membrane's hydrophilicity to decay, weakening its long-term stability, while membrane fouling caused by protein adsorption can lead to reduced membrane flux. Therefore, it is necessary to introduce new additives to simultaneously improve the membrane's water flux, long-term stability, and biocompatibility. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing an anti-pollution and anti-coagulation membrane based on in situ micro-crosslinking-polymerization, which can introduce new additives during the preparation of hollow fiber membranes to simultaneously improve the water flux, long-term stability and biocompatibility of the membrane.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for preparing an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization comprises the following steps:

[0007] Step 1: Dissolve PES and PVP in a solvent and mix to form an initial solution;

[0008] Step 2: Add SBMA and NaSS monomers to the initial solution and mix to form a homogeneous solution;

[0009] Step 3: adding a crosslinking agent and an initiator to the uniform solution and stirring to form a uniform casting solution;

[0010] Step 4: Degassing the casting solution;

[0011] Step 5: preparing hollow fiber membrane;

[0012] In step 3, the initiator generates free radicals when it decomposes, which triggers the double bonds of SBMA and NaSS to open and form monomer free radicals; the cross-linking agent forms a covalent bond between SBMA and NaSS through bonding, thereby constructing a cross-linked network.

[0013] Preferably, in step 1, the PES and PVP are dissolved in NMP solvent and stirred for 4-6 hours to form the initial solution.

[0014] Preferably, in step 2, after adding SBMA and NaSS monomers to the initial solution, stirring is performed for 2-4 hours to form a homogeneous solution.

[0015] Preferably, in step 3, after adding the crosslinking agent and the initiator to the uniform solution, the solution is stirred for 10-12 hours to form a uniform casting solution.

[0016] Preferably, in step 5, the preparation method of the hollow fiber membrane is as follows:

[0017] S1: The casting solution obtained in step 4 is extruded through a spinneret and then enters an external coagulation bath to obtain the desired hollow fiber membrane;

[0018] S2: The cleaning module cleans the hollow fiber membrane.

[0019] S3: The drying module dries the hollow fiber membrane to obtain a hollow fiber membrane product.

[0020] Preferably, in S1, the spinneret is provided with spinnerets and channels coaxially arranged with the spinnerets, the casting liquid is extruded through the spinnerets to form a hollow fiber membrane, and the channels are used to input an internal coagulant into the hollow fiber membrane.

[0021] Preferably, the internal coagulant is deionized water, and the external coagulation bath is a mixture of water and a solvent.

[0022] Preferably, the temperature of the spinneret is 50-60°C.

[0023] Preferably, there are several cleaning modules, and the cleaning time of the hollow fiber membrane in each cleaning module is 2-3 minutes.

[0024] Preferably, there are several drying modules, and gradient drying can be set. The drying time of the hollow fiber membrane in each cleaning module is 2-3 minutes.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] In the present invention, the initial solution in step 2 can be blended with betaine SBMA (hydrophilic monomer sulfonylcholine methacrylate) and NaSS (sodium styrene sulfonate) through a free radical copolymerization reaction. The initiator (such as AIBN (azobisisobutyronitrile)) decomposes to generate free radicals, which trigger the opening of the double bonds of SBMA and NaSS to form monomer free radicals. The crosslinker participates in the polymerization through the double bonds, forming a covalent bond between SBMA and NaSS to construct a crosslinked network.

[0027] This cross-linked network can fix the hydrophilic copolymer in the hydrophobic PES matrix and also impart structural stability to the membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 This is a diagram of the polymerization principle of the present invention.

[0030] Figure 2 2 is a comparison chart of the protein adsorption amount changes between the embodiments of the present invention and the prior art. DETAILED DESCRIPTION

[0031] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the embodiments of the present invention. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0032] In the description of the embodiments of the present invention, it should be understood that the terms "length", "vertical", "horizontal", "top", "bottom", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the embodiments of the present invention.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0034] In the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," "fixed," etc. should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on specific circumstances.

[0035] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0036] The disclosure below provides many different embodiments or examples for implementing different structures of the embodiments of the present invention. In order to simplify the disclosure of the embodiments of the present invention, the components and configurations of specific examples are described below. Of course, these are merely examples and are not intended to limit the embodiments of the present invention. In addition, the embodiments of the present invention may repeat reference numerals and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0037] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0038] Example 1

[0039] See Figure 1-Figure 2 This embodiment discloses a method for preparing an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization, comprising the following steps:

[0040] Step 1: Dissolve PES and PVP in a solvent and mix to form an initial solution;

[0041] Step 2: Add SBMA and NaSS monomers to the initial solution and mix to form a homogeneous solution;

[0042] Step 3: adding a crosslinking agent and an initiator to the uniform solution and stirring to form a uniform casting solution;

[0043] Step 4: Degassing the casting solution;

[0044] Step 5: preparing hollow fiber membrane;

[0045] In step 3, the initiator generates free radicals when it decomposes, which triggers the double bonds of SBMA and NaSS to open and form monomer free radicals; the cross-linking agent forms a covalent bond between SBMA and NaSS through bonding, thereby constructing a cross-linked network.

[0046] In this embodiment, the mass parts of the raw materials for preparing the casting solution are as follows: 16-20 parts of PES, 1-5 parts of SBMA, 0.5-3 parts of NaSS, 70-75 parts of solvent and 2-6 parts of PVP; wherein, the cross-linking agent is 0.2-1 parts, the initiator is 0.1-0.5 parts; the PES is polyethersulfone, the PVP is polyvinylpyrrolidone, and the solvent is N-methylpyrrolidone (NMP) / N, N-dimethylacetamide (DMAc) / N or N-dimethylformamide (DMF); in step 2, the initial The starting solution can be blended with a hydrophilic monomer, SBMA (sulfonylcholine methacrylate), and sodium styrene sulfonate (NaSS), through a free radical copolymerization reaction with a crosslinker, such as N,N-methylenebisacrylamide or MBA (N,N"-methylenebisacrylamide). At 60-70°C, an initiator, such as AIBN (azobisisobutyronitrile), decomposes to produce free radicals, which trigger the opening of the double bonds in SBMA and NaSS, forming monomeric free radicals. The crosslinker participates in the polymerization through the double bonds, forming covalent bonds between SBMA and NaSS and building a crosslinked network.

[0047] This cross-linked network can fix the hydrophilic copolymer (a copolymer formed by SBMA and NaSS) in the hydrophobic PES matrix, while giving the membrane structure stability. During the polymerization process, the two short-chain molecules of SBMA and NaSS undergo simple polymerization in an alkaline environment through initiators and cross-linkers to generate longer chains, which are cross-linked with the long-chain molecules of PES to form a semi-interpenetrating network structure; after polymerization, the casting liquid is made into an ultrafiltration membrane by a phase inversion method. During the replacement of solvent and water, the hydrophilic copolymer is enriched on the membrane surface and pore wall to form a hydrophilic surface layer. When the hollow fiber membrane is actually used, SBMA contains sulfonic acid groups (-SO3 - ) and quaternary ammonium salts (-N +(CH3)2) groups bind a large number of water molecules through electrostatic interaction and hydrogen bonding to form a dense hydration layer (about 8 water molecules / sulfonic acid unit). The hydration layer acts as a physical barrier to prevent direct contact between proteins (such as BSA, fibrinogen) and the membrane surface, significantly reducing the occurrence of membrane fouling. At the same time, as a zwitterionic polymer, SBMA's positive charge of the quaternary ammonium salt and the negative charge of the sulfonic acid group balance each other, avoiding the specific adsorption of proteins caused by a single charge (such as cationic groups easily adsorb negatively charged proteins). The sulfonic acid group (-SO3 - ) binds to Ca in plasma through electrostatic adsorption 2 + , can reduce the activity of coagulation factor (thrombin); at the same time, sulfonic acid group (-SO3 - ) can also inhibit platelet activation and reduce thrombosis.

[0048] The SBMA provides a durable hydration layer, while the NaSS imparts anticoagulant properties. The two complement each other in their copolymerization. The semi-interpenetrating network structure ensures uniform distribution of the copolymer throughout the membrane, avoiding the peeling problem associated with traditional coating methods and enhancing the long-term stability of the membrane structure.

[0049] Further optimization, in step 1, after the PES and PVP are dissolved in the NMP solvent, stirring is performed for 4-6 hours to form the initial solution. The stirring is performed to uniformly dissolve the solute in the solvent to form a uniform solution.

[0050] Further optimization is performed, in step 2, after adding SBMA and NaSS monomers to the initial solution, stirring is performed for 2-4 hours to form a homogeneous solution, so that SBMA and NaSS are evenly distributed in the solution.

[0051] Further optimization involves adding a crosslinker and initiator to the homogeneous solution in step 3, followed by stirring for 10-12 hours to form a uniform casting solution. This ensures that the initiator and crosslinker are evenly distributed throughout the solution, allowing the solution to uniformly produce a copolymer and that the copolymer formed by SBMA and NaSS is uniformly crosslinked within the PES backbone.

[0052] Further optimization, in step 4, the casting solution is degassed at 60-70° C. for 12-24 hours.

[0053] Example 2

[0054] See Figure 1 - Figure 2, this embodiment is further optimized based on Example 1. In step 5, the hollow fiber membrane preparation method is as follows:

[0055] S1: The casting solution obtained in step 4 is extruded through a spinneret and then enters an external coagulation bath to obtain the desired hollow fiber membrane;

[0056] S2: The cleaning module cleans the hollow fiber membrane.

[0057] S3: The drying module dries the hollow fiber membrane to obtain a hollow fiber membrane product.

[0058] In this embodiment, the hollow fiber filaments extruded from the spinneret in S1 enter the external coagulation bath through the air gap for molding; the spinning speed is 20 m / min, and the air gap is 1-5 cm.

[0059] Further optimizing, in S1, the spinneret is provided with spinnerets and channels coaxially arranged with the spinnerets. The casting solution is extruded through the spinnerets to form a hollow fiber membrane. The channels are used to introduce an internal coagulant into the hollow fiber membrane. In this embodiment, the internal coagulant introduced into the hollow fiber membrane through the channels is used to rapidly phase separate the casting solution and form a support layer. Upon entry into the external coagulation bath, the hollow fiber membrane can slow the phase separation rate, increase the occurrence of delayed liquid-liquid phase separation, reduce the rate of finger-like macropores, and improve the mechanical strength of the hollow fiber membrane.

[0060] The internal coagulant is deionized water, and the external coagulation bath is a mixture of water and a solvent. In this embodiment, the solvent is NMP, and the volume ratio of water to NMP is 80:20. By using the same aqueous solution as the solvent in the external coagulation bath, the phase separation rate outside the membrane can be slowed, thereby increasing the membrane's retention rate.

[0061] Further optimization, the temperature of the spinneret is 50-60°C.

[0062] Further optimization is that there are several cleaning modules, and the cleaning time of the hollow fiber membrane in each cleaning module is 2-3 minutes. The cleaning module is used to remove residual solvents and small molecule dissolutions in the hollow fiber membrane. In this embodiment, the cleaning module is a conventional ultrasonic cleaning module in the prior art (such as YF3-YF6 series), including a primary cleaning tank, a secondary cleaning tank and a tertiary rinsing tank. The primary cleaning liquid in the primary cleaning is a 30% ethanol aqueous solution, the cleaning temperature of the primary cleaning tank is set to 40°C, the ultrasonic frequency is 40kHz (low-frequency deep penetration), and the cleaning time is 2.5-3min. The hollow fiber membrane can dissolve residual NMP and small molecular polymers in the primary cleaning; the secondary cleaning liquid in the secondary cleaning is deionized water, the cleaning temperature of the secondary cleaning is set to 35°C, the ultrasonic frequency is 120kHz (high-frequency surface stripping), and the cleaning time is 2.5-3min. The hollow fiber membrane can remove organic solvents and ionic impurities in the secondary cleaning; the rinsing liquid in the tertiary rinsing is ultrapure water at 25°C, and the cleaning time is 2-2.5min. The cleanliness of the hollow fiber membrane meets the standard after the tertiary rinsing treatment.

[0063] Further optimization, the drying modules have several, gradient drying can be set, and the drying time of the hollow fiber membrane in each cleaning module is 2-3 minutes. In this embodiment, the drying module is a conventional hot air dryer in the prior art.

[0064] Example 3

[0065] In this embodiment, the mass parts of the raw materials for preparing the casting solution are as follows: 18 parts of polyethersulfone (PES), 2 parts of betaine (SBMA), 3 parts of sodium styrene sulfonate (NaSS), 73.6 parts of N-methylpyrrolidone (NMP), 3 parts of polyvinylpyrrolidone (PVP), 0.3 parts of a cross-linking agent (MBA (N,N"-methylenebisacryloyl) and 0.3 parts of an initiator (AIBN (azobisisobutyronitrile)); wherein, PES and PVP are dissolved in NMP solvent and stirred for 6 hours to form a uniform solution; SBMA and NaSS monomers are then added and stirred for 4 hours; finally, the cross-linking agent and initiator are added and stirred for 12 hours to obtain a uniform casting solution; the casting solution is degassed at 65°C for 12 hours; the spinneret temperature is 60°C, the air gap is 5 cm, and the spinning speed is 20 m / min.

[0066] Example 4

[0067] In this embodiment, the mass parts of the raw materials for preparing the casting solution are as follows: 18 parts of polyethersulfone (PES), 3 parts of betaine (SBMA), 2 parts of sodium styrene sulfonate (NaSS), 73.6 parts of N-methylpyrrolidone (NMP), 3 parts of polyvinylpyrrolidone (PVP), 0.3 parts of a cross-linking agent (MBA (N,N"-methylenebisacryloyl) and 0.3 parts of an initiator (AIBN (azobisisobutyronitrile)); wherein, PES and PVP are dissolved in NMP solvent and stirred for 6 hours to form a uniform solution; then SBMA and NaSS monomers are added and stirring is continued for 4 hours; finally, the cross-linking agent and initiator are added and stirred for 12 hours to obtain a uniform casting solution; the casting solution is degassed at 65°C for 12 hours; the spinneret temperature is 60°C, the air gap is 5 cm; and the spinning speed is 20 m / min.

[0068] Example 5

[0069] In this embodiment, the mass parts of the raw materials for preparing the casting solution are as follows: 18 parts of polyethersulfone (PES), 5 parts of betaine (SBMA), 2 parts of sodium styrene sulfonate (NaSS), 71.2 parts of N-methylpyrrolidone (NMP), 3 parts of polyvinylpyrrolidone (PVP), 0.5 parts of a cross-linking agent (MBA (N,N"-methylenebisacryloyl) and 0.3 parts of an initiator (AIBN (azobisisobutyronitrile)); wherein, PES and PVP are dissolved in NMP solvent and stirred for 6 hours to form a uniform solution; then SBMA and NaSS monomers are added and stirring is continued for 4 hours; finally, the cross-linking agent and initiator are added and stirred for 12 hours to obtain a uniform casting solution; the casting solution is degassed at 65°C for 12 hours; the spinneret temperature is 60°C, the air gap is 5 cm; and the spinning speed is 20 m / min.

[0070] Table 1 shows the performance comparison of the hollow fiber membranes of Examples 3 to 5 and common hemodialysis membranes on the market:

[0071]

[0072] In this embodiment, the membrane in the comparative example is a conventional high-pass polyethersulfone hemodialysis membrane in the prior art (for example, the ZOE series hemodialyzer with national medical device registration number 20223100958);

[0073] As shown in Table 1, the activated partial thromboplastin time (APTT) and thrombin time (TT) were compared using a kit (Siemens); the ultrafiltration coefficient was measured and calculated under the conditions of a blood flow rate QB = 300 ml / min and a transmembrane pressure TMP = 100 mmHg (bovine plasma); protein adsorption was tested using a BAS instrument, and the change in protein adsorption over time can be found in Figure 1 Compared with the comparative example (high-pass), the activated partial thromboplastin time of Example 1 is 17 seconds longer on average, the thrombin time is 3 seconds longer on average, and the protein adsorption is 3.4 μg / cm2 less, which is more excellent in terms of anti-coagulation and anti-fouling performance.

[0074] Example 6

[0075] See Figure 1-Figure 2This embodiment is further optimized on the basis of the first and second embodiments. In this embodiment, the membrane filaments extruded through the spinneret in S1 sequentially pass through the first external coagulation bath and the second external coagulation bath arranged in parallel. The volume ratio of water and NMP of the internal and external coagulants in the first external coagulation bath is 80:20; the volume ratio of water and NMP of the internal and external coagulants in the second external coagulation bath is 95:5; the membrane filaments pass through the first external coagulation bath (staying for 3s) and the second external coagulation bath in sequence at a speed of 20m / min. (stay for 5s), wherein the high concentration of external coagulant in the first external coagulation bath can delay phase separation and form a dense sponge layer; the low concentration of external coagulant in the second external coagulation bath can accelerate phase separation and generate finger-shaped pores; the number of the first external coagulation bath and the second external coagulation bath and the stay frequency of the membrane filaments in the first external coagulation bath and the second external coagulation bath can be set according to actual needs, so as to control the ratio of the sponge layer and the finger-shaped pores and reduce the defect rate of the membrane structure (surface pore dispersion) of the traditional single coagulation bath.

[0076] Example 7

[0077] See Figure 1-Figure 2 This embodiment is further optimized on the basis of Example 1 and Example 2. In this embodiment, the internal coagulant is a mixture of diethylene glycol monomethyl ether (DEGME) and polyethylene glycol 400 (PEG400), and the volume ratio of DEGME to PEG 400 is 7:3.

[0078] DEGME is a polar organic solvent (boiling point 194°C) that is partially compatible with the casting solution solvent NMP (mutual solubility is approximately 60% at 25°C). Unlike ionized water, it does not directly induce coagulation through strong solvent-nonsolvent exchange. PEG400 is a low-toxic polymer ether that further reduces its repulsion with NMP, thus avoiding the problem that the strong coagulation ability of ionized water can easily lead to excessive phase separation, which may cause excessive development of finger-like pores inside the membrane and affect mechanical strength.

[0079] The mixture of DEGME and ethylene glycol 400 promotes phase separation by destroying the thermodynamic stability of the casting solution: the partial compatibility of DEGME and NMP reduces the solubility of the solvent in the casting solution for PES, while the weak hydrogen bonding between PEG400 and PVP further weakens the interaction between the polymer and the solvent, ultimately causing the casting solution to separate from the homogeneous phase into a polymer-rich phase (membrane structure) and a solvent-rich phase (pores).

[0080] Further optimization was performed, and the temperature of the mixture of DEGME and polyethylene glycol 400 was 35-40°C, which matched the spinneret temperature, to avoid local phase separation fluctuations caused by temperature differences. The flow rate was 0.8-1.2 mL / min, and the flow rate could be adjusted according to the spinneret hole diameter to ensure that the internal coagulant formed a stable liquid core in the membrane cavity.

[0081] The process of the internal coagulant (DEGME / PEG400 mixed solution) entering the membrane cavity through the coaxial channel of the spinneret is as follows:

[0082] Initial stage (0-2s): The internal coagulant contacts the inner wall of the casting solution and slowly penetrates through weak interactions (hydrogen bonds between PEG400 and PVP), reducing the solubility of the local solvent for PES, inducing slow phase separation, and forming a dense inner surface support layer;

[0083] Mid-term (2-5s): With the further diffusion of the internal coagulant and NMP, the thermodynamic stability of the casting solution continues to decrease, the polymer-rich phase gradually separates, and a uniform sponge-like pore structure is formed (the proportion of finger-like pores is reduced);

[0084] Later stage (after 5s): the membrane filaments enter the external coagulation bath (water / NMP=80:20). The strong non-solvent effect of the external coagulation bath accelerates the phase separation of the outer surface, and cooperates with the slow phase separation of the internal coagulant to form a membrane structure with dense inner and uniform outer structure.

[0085] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing an anti-pollution and anti-coagulation membrane based on in situ micro-crosslinking-polymerization, The method comprises the following steps, which is characterized in that: Step 1: Dissolve PES and PVP in a solvent and mix to form an initial solution; Step 2: Add SBMA and NaSS monomers to the initial solution and mix to form a homogeneous solution; Step 3: adding a crosslinking agent and an initiator to the uniform solution and stirring to form a uniform casting solution; Step 4: Degassing the casting solution; Step 5: preparing hollow fiber membrane; In step 3, the initiator generates free radicals when it decomposes, which triggers the double bonds of SBMA and NaSS to open and form monomer free radicals; the cross-linking agent forms a covalent bond between SBMA and NaSS through bonding, thereby constructing a cross-linked network.

2. The method for preparing an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization according to claim 1, characterized in that: In step 1, the PES and PVP are dissolved in NMP solvent and stirred for 4-6 hours to form the initial solution.

3. The method for preparing an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization according to claim 2, characterized in that: In step 2, SBMA and NaSS monomers are added to the initial solution and stirred for 2-4 hours to form a homogeneous solution.

4. The method for preparing an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization according to claim 3, characterized in that: In step 3, after adding a crosslinking agent and an initiator to the uniform solution, the solution is stirred for 10-12 hours to form a uniform casting solution.

5. The method for preparing an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization according to claim 1, characterized in that: In step 5, the hollow fiber membrane is prepared as follows: S1: The casting solution obtained in step 4 is extruded through a spinneret and then enters an external coagulation bath to obtain the desired hollow fiber membrane; S2: The cleaning module cleans the hollow fiber membrane. S3: The drying module dries the hollow fiber membrane to obtain a hollow fiber membrane product.

6. The method for preparing an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization according to claim 5, characterized in that: In S1, the spinneret is provided with spinnerets and channels coaxially arranged with the spinnerets. The casting liquid is extruded through the spinnerets to form a hollow fiber membrane. The channels are used to input an internal coagulant into the hollow fiber membrane.

7. The method for preparing an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization according to claim 6, characterized in that: The internal coagulant is deionized water, and the external coagulation bath is a mixture of water and solvent.

8. The method for preparing an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization according to claim 5, characterized in that: The temperature of the spinneret is 50-60°C.

9. The method for preparing an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization according to claim 5, characterized in that: There are several cleaning modules, and the cleaning time of the hollow fiber membrane in each cleaning module is 2-3 minutes.

10. The method for preparing an anti-pollution and anti-coagulation membrane based on in-situ micro-crosslinking-polymerization according to claim 5, characterized in that: There are several drying modules, which can be set to gradient drying. The drying time of the hollow fiber membrane in each cleaning module is 2-3 minutes.

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