Self-polymerized microporous polymer hollow fiber ultrafiltration membrane as well as preparation method and application thereof

Abstract

The invention provides a self-polymerized microporous polymer hollow fiber ultrafiltration membrane as well as a preparation method and application thereof, and belongs to the technical field of ultrafiltration membranes. The preparation method comprises the following steps: mixing a self-polymerized microporous polymer (PIM), a plasticizer and an organic solvent to obtain a spinning solution, and carrying out wet spinning on the spinning solution in one step to obtain the hollow fiber ultrafiltration membrane. According to the invention, a self-polymerized microporous polymer (PIM) is added in the spinning process, and the PIM material realizes molecular-level self-assembly through dynamic covalent bonds (such as imine bonds and borate bonds) to form a pore channel continuous network structure, so that the performance of the ultrafiltration membrane is improved. The hollow fiber ultrafiltration membrane prepared from the self-polymerization microporous polymer with the specific structure has good hydrophilic performance, the permeability coefficient of the ultrafiltration membrane is 100 Lm <-2 > h <-1 > or above, efficient filtration can be achieved at low pressure, and energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrafiltration membranes, and particularly to a self-polymerized microporous polymer hollow fiber ultrafiltration membrane, a preparation method thereof, and an application thereof. Background Art

[0002] With the increasing urgency of global water resource shortage, environmental pollution control requirements, and the rapid development of the biomedical industry, membrane separation technology, as an energy-efficient separation means, is experiencing unprecedented development opportunities. In water treatment, ultrafiltration membranes have become one of the core technologies in the membrane separation field due to their nanoscale pore sizes (usually 1 - 100 nm) and pore size sieving effects. Ultrafiltration membranes can effectively remove suspended solids, bacteria, and macromolecular organic matter in water; in the food processing field, they are helpful for liquid concentration, purification, and separation; while in the biomedical industry, ultrafiltration membranes are widely used in important processes such as cell separation and protein purification. However, traditional ultrafiltration membrane production methods usually face problems such as low production efficiency, unstable membrane performance, serious membrane fouling, and environmental pollution, which limit their further development in practical applications. Summary of the Invention

[0003] The purpose of the present invention is to provide a self-polymerized microporous polymer hollow fiber ultrafiltration membrane, a preparation method thereof, and an application thereof, which can improve the production efficiency of ultrafiltration membranes, obtain ultrafiltration membranes with stable performance, and have strong environmental friendliness.

[0004] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a preparation method of a self-polymerized microporous polymer hollow fiber ultrafiltration membrane, comprising the following steps:

[0006] Mix a self-polymerized microporous polymer, a plasticizer, and an organic solvent to obtain a spinning solution;

[0007] Mix water and glycerol to obtain a core liquid;

[0008] Perform wet spinning on the spinning solution and the core liquid, and then solidify in a coagulation bath to obtain a self-polymerized microporous polymer hollow fiber ultrafiltration membrane;

[0009] The preparation monomers of the self-polymerized microporous polymer include tetrafluoroterephthalonitrile and 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethylspirobiindane.

[0010] Preferably, the plasticizer includes diethylene glycol, glycerol, polydimethylsiloxane, or dioctyl phthalate; the organic solvent includes tetrahydrofuran, chloroform, or N,N-dimethylacetamide.

[0011] Preferably, the contents of the components in the spinning solution are as follows: self-polymerized microporous polymer 22-30 wt%, plasticizer 7-10 wt%, and organic solvent 60-70 wt%.

[0012] Preferably, the mass ratio of water to glycerol in the core solution is 80:20 to 20:80.

[0013] Preferably, the preparation method of the self-polymerized microporous polymer comprises the following steps:

[0014] Mix tetrafluoroterephthalonitrile, 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethylspirobiindane, potassium carbonate and N,N-dimethylacetamide, carry out a polymerization reaction, and then successively carry out precipitation, boiling water treatment and vacuum drying to obtain the self-polymerized microporous polymer.

[0015] Preferably, the molar concentration of tetrafluoroterephthalonitrile in N,N-dimethylacetamide is 10-30 mmol / L, the molar concentration of 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethylspirobiindane in N,N-dimethylacetamide is 15-50 mmol / L, and the molar concentration of potassium carbonate in N,N-dimethylacetamide is 50-100 mmol / L.

[0016] Preferably, the temperature of the polymerization reaction is 100-200 °C and the time is 30-60 min.

[0017] The present invention provides a self-polymerized microporous polymer hollow fiber ultrafiltration membrane prepared by the preparation method described in the above technical solution, with an inner diameter of 0.5-0.8 mm and an outer diameter of 1.0-1.3 mm.

[0018] Preferably, at 0.1 MPa, the permeability coefficient of the self-polymerized microporous polymer hollow fiber ultrafiltration membrane > 100 Lm -2 h -1 .

[0019] The present invention provides the application of the self-polymerized microporous polymer hollow fiber ultrafiltration membrane described in the above technical solution in the fields of water treatment, food separation or pharmaceutical separation.

[0020] The present invention provides a preparation method of a self-polymerized microporous polymer hollow fiber ultrafiltration membrane. Mix a self-polymerized microporous polymer (PIM), a plasticizer and an organic solvent to obtain a spinning solution, and the spinning solution is directly prepared into a hollow fiber ultrafiltration membrane by wet spinning. In the spinning process of the present invention, a self-polymerized microporous polymer (PIM) is added. The PIM material realizes molecular-level self-assembly through dynamic covalent bonds (such as imine bonds and borate ester bonds) to form a continuous pore network structure, thereby improving the performance of the ultrafiltration membrane. The hollow fiber ultrafiltration membrane prepared by using a self-polymerized microporous polymer with a specific structure in the present invention has good hydrophilic properties, and the ultrafiltration membrane permeability coefficient is 100 Lm-2 h -1 As described above, it can achieve efficient filtration under low pressure and reduce energy consumption.

[0021] In addition, the present invention prepares the hollow fiber ultrafiltration membrane by a one-step method. The preparation process is relatively simple, the preparation cost is relatively low, it has a high cost performance, is suitable for large-scale production, and produces less waste during the production process, with strong environmental protection. The method of the present invention simplifies multiple steps required in the traditional film-forming process, reduces the complexity of the system, and improves the production efficiency. At the same time, the simplified process flow is more conducive to realizing automated production, thus having significant advantages in industrial production.

[0022] The present invention can adjust the physical and chemical properties of the core liquid according to the specific requirements of the membrane, and optimize the membrane-forming process and performance of the membrane.

[0023] The hollow fiber ultrafiltration membrane prepared by the present invention can be widely used in various application fields, such as water treatment, food separation, and medicine. Description of the Drawings

[0024] Figure 1 Schematic diagram of the synthesis process of the self-polymerized microporous polymer in Example 1;

[0025] Figure 2 XRD pattern of the self-polymerized microporous polymer prepared in Example 1;

[0026] Figure 3 FTIR pattern of the self-polymerized microporous polymer prepared in Example 1;

[0027] Figure 4 Thermogravimetric curve of the self-polymerized microporous polymer prepared in Example 1;

[0028] Figure 5 Schematic diagram of the process for preparing the hollow fiber ultrafiltration membrane in Example 1;

[0029] Figure 6 Inner surface SEM image of the hollow fiber ultrafiltration membrane prepared in Example 1;

[0030] Figure 7 Cross-section SEM image of the hollow fiber ultrafiltration membrane prepared in Example 1;

[0031] Figure 8 Contact angle image of the hollow fiber ultrafiltration membrane prepared in Example 1. Detailed Description of the Invention

[0032] In the present invention, unless otherwise specified, the raw materials or reagents required for preparation are all commercially available products well-known to those skilled in the art.

[0033] The present invention provides a method for preparing a self-polymerized microporous polymer hollow fiber ultrafiltration membrane, comprising the following steps:

[0034] Mix a self-polymerized microporous polymer, a plasticizer and an organic solvent to obtain a spinning solution;

[0035] Mix water and glycerol to obtain a core liquid;

[0036] After wet spinning the spinning solution and the core liquid, solidify in a coagulation bath to obtain a self-polymerized microporous polymer hollow fiber ultrafiltration membrane;

[0037] The preparation monomers of the self-polymerized microporous polymer include tetrafluoroterephthalonitrile and 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethylspirobiindane.

[0038] In the present invention, the method for preparing the self-polymerized microporous polymer (PIM) preferably comprises the following steps:

[0039] Mix tetrafluoroterephthalonitrile, 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethylspirobiindane, potassium carbonate and N,N-dimethylacetamide, carry out a polymerization reaction, and then successively carry out precipitation, boiling water treatment and vacuum drying to obtain a self-polymerized microporous polymer.

[0040] In the present invention, the molar concentration of tetrafluoroterephthalonitrile in N,N-dimethylacetamide is preferably 10-30 mmol / L, more preferably 10-20 mmol / L; the molar concentration of 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethylspirobiindane in N,N-dimethylacetamide is 15-50 mmol / L, more preferably 30 mmol / L, and the molar concentration of potassium carbonate in N,N-dimethylacetamide is 50-100 mmol / L, more preferably 70-80 mmol / L.

[0041] The present invention preferably adds tetrafluoroterephthalonitrile, 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethylspirobiindane, anhydrous potassium carbonate and N,N-dimethylacetamide to a reaction vessel, stir evenly at room temperature, transfer the reaction device to an oil bath for heating and mechanical stirring, and carry out a polymerization reaction.

[0042] In the present invention, the temperature of the polymerization reaction is preferably 100-200 °C, more preferably 200 °C, and the time is preferably 30-60 min, more preferably 30 min.

[0043] After the polymerization reaction is completed, it is preferred in the present invention to cool the reaction product to be reacted, pour the PIM reaction product into anhydrous methanol for precipitation, filter the obtained precipitate, dissolve it with chloroform, and precipitate it again into anhydrous methanol. After subjecting the obtained fluorescent yellow solid to boiling water treatment, it is dried in a vacuum drying oven under vacuum to obtain self-polymerized microporous polymer (PIM) powder.

[0044] In the present invention, based on 50 - 100 g of the PIM reaction product, the volume of anhydrous methanol required for precipitation in anhydrous methanol is 300 - 600 mL, more preferably 400 mL; the volume of chloroform required for dissolution is 50 - 100 mL, more preferably 50 mL; the volume of anhydrous methanol required for re-precipitation in anhydrous methanol is 300 - 600 mL, more preferably 400 mL.

[0045] In the present invention, the time of the boiling water treatment is preferably 6 - 12 h, more preferably 10 h; the temperature of the vacuum drying is preferably 80 - 100 °C, more preferably 80 °C, and the time is preferably 12 - 24 h, more preferably 12 h.

[0046] In the present invention, the content of each component in the spinning solution is preferably: self-polymerized microporous polymer 22 - 30 wt%, plasticizer 7 - 10 wt%, organic solvent 60 - 70 wt%.

[0047] In the present invention, the content of the self-polymerized microporous polymer in the spinning solution is more preferably 25 - 30 wt%, the content of the plasticizer is more preferably 8 - 10 wt%, and the content of the organic solvent is more preferably 62 - 67 wt%.

[0048] In the present invention, the plasticizer preferably includes diethylene glycol, glycerol, polydimethylsiloxane or dioctyl phthalate; the organic solvent preferably includes tetrahydrofuran, chloroform or N,N-dimethylacetamide.

[0049] In the present invention, the self-polymerized microporous polymer provides the matrix structure framework of the membrane, the plasticizer improves the flexibility and stability of the membrane, and the organic solvent fully dissolves and uniformly disperses other components to ensure the consistency, fluidity and stability of the spinning solution.

[0050] In the present invention, it is preferred to mix the self-polymerized microporous polymer, the plasticizer and the organic solvent and then crush them to form a spinning solution. There are no special limitations on the crushing in the present invention, and the materials can be mixed evenly by crushing according to the methods well-known in the art.

[0051] In the present invention, the mass ratio of water to glycerol in the core liquid is preferably 80:20 to 20:80, more preferably 40:60 or 60:40. The addition of glycerol helps to adjust the viscosity and permeability of the core liquid, thereby affecting the formation of the membrane pore structure and the separation performance of the final membrane. By adjusting the ratio of water to glycerol, the properties of the core liquid can be optimized to meet the requirements of different membrane preparations.

[0052] In the present invention, the spinning solution is preferably extruded through the spinneret holes of the casting solution at room temperature, while the core liquid is injected through the core liquid holes and fills the hollow fiber structure; the extruded membrane filaments vertically fall into the coagulation bath to complete the preliminary forming of the membrane, and the formed membrane filaments are collected by a wire collecting device. After drying, a self-polymerized microporous polymer hollow fiber ultrafiltration membrane is obtained.

[0053] In the present invention, the coagulation bath is preferably water, the temperature of the coagulation bath is preferably 20 to 70 °C, more preferably 30 to 50 °C, and the coagulation time is preferably 1 to 15 minutes, more preferably 10 minutes.

[0054] The present invention uses a self-microporous polymer as the polymer material, ensuring the structural uniformity of the hollow fiber membrane and its high separation performance, while having high production stability and controllability. By optimizing the temperature and time of the coagulation bath, the pore structure and physical properties of the membrane can be precisely controlled to improve the final use effect of the membrane. This spinning process has low cost and high automation level, and is suitable for large-scale industrial production.

[0055] The present invention provides a self-polymerized microporous polymer hollow fiber ultrafiltration membrane prepared by the preparation method described in the above technical solution, with an inner diameter of 0.5 to 0.8 mm, more preferably 0.7 mm, and an outer diameter of 1.0 to 1.3 mm, more preferably 1.2 mm.

[0056] In the present invention, at 0.1 MPa, the permeability coefficient of the self-polymerized microporous polymer hollow fiber ultrafiltration membrane > 100 Lm -2 h -1 .

[0057] The present invention provides the application of the self-polymerized microporous polymer hollow fiber ultrafiltration membrane described in the above technical solution in the fields of water treatment, food separation or pharmaceutical separation. The present invention has no special limitation on the method of the application, and it can be applied according to the methods well-known in the art.

[0058] In addition, for the batch spinning modularization of the hollow fiber membrane, the present invention can be easily integrated and expanded by optimizing the spinning process flow and the membrane pore structure design to meet the operating requirements of different scales and demands.

[0059] The specific embodiments of the present invention will be described in detail below. However, it should be understood that the protection scope of the present invention is not limited by the specific embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are all conventional methods unless otherwise specified.

[0060] The following experimental methods and detection methods are all conventional methods unless otherwise specified; the following reagents and raw materials are all commercially available unless otherwise specified.

[0061] The permeability coefficient P in the present invention w is defined as: under certain conditions, the mass flowing out per unit time per unit area per unit. P w = Δm / (ρAΔt), with the unit of Lm -2 h -1 , where Δm (kg) is the mass increment of the filtrate within the separation time of Δt (h), ρ is the density of the filtrate (kg L -1 ), and A (m 2 ) is the effective filtration area.

[0062] Example 1

[0063] As Figure 1 shown, 10 mmol of tetrafluoroterephthalonitrile, 30 mmol of 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethylspirobifluorene, 70 mmol of anhydrous potassium carbonate, and 1000 mL of N,N-dimethylacetamide were added to the reactor of the water separator, stirred at room temperature for 60 min. After stirring evenly, the reaction device was transferred to an oil bath at 200 °C for heating and mechanical stirring for 30 min. After the reaction system cooled, every 50 g of the reaction product was poured into 400 mL of anhydrous methanol for precipitation. The obtained precipitate was filtered, the precipitate was dissolved in 50 mL of chloroform, and then precipitated again into 400 mL of anhydrous methanol. The obtained fluorescent yellow solid was treated in boiling water for 10 h and dried in a vacuum drying oven at 80 °C for 12 h to obtain a self-polymerized microporous polymer (PIM) powder, denoted as PIM-1;

[0064] According to the ratio, 22 wt% of the self-polymerized microporous polymer prepared above, 8 wt% of diethylene glycol, and 70 wt% of tetrahydrofuran were mixed at room temperature to obtain a spinning solution;

[0065] Water and glycerol were mixed according to a mass percentage of 80:20 to obtain a core liquid;

[0066] As Figure 4As shown, at room temperature, the spinning solution is extruded through the spinneret holes of the casting solution, while the core liquid is injected through the core liquid holes. The extruded membrane filaments vertically fall into a coagulation bath (tap water) at 20 °C, with a coagulation time of 10 minutes. After forming, the filaments are collected by a wire collecting device and dried to obtain a self-polymerized microporous polymer hollow fiber ultrafiltration membrane. The inner diameter is 0.7 mm, the outer diameter is 1.2 mm, and the permeability coefficient is 120 Lm -2 h -1 。

[0067] Figure 1 Figure 1 is a schematic diagram of the synthesis process of the self-polymerized microporous polymer in Example 1. The self-polymerized microporous polymer PIM is synthesized by the reaction of the monomer 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethylspirobiindane and tetrafluoroterephthalonitrile.

[0068] Figure 2 Figure 2 is the XRD pattern of the self-polymerized microporous polymer prepared in Example 1. The XRD pattern shows two polymer peaks at 2θ of 14.0 degrees and 22.6 degrees, and the corresponding d spacings are and attributed to the micropores and effective chain segments between the polymer chains, respectively.

[0069] Figure 3 Figure 3 is the FTIR pattern of the self-polymerized microporous polymer prepared in Example 1. The FTIR pattern shows a carbonyl (C=O) absorption peak near 1600 cm-1. Characteristic C-H vibration peaks of the aromatic ring are in the ranges of 3000 - 3100 cm-1 and 1600 - 1450 cm-1. The characteristic peaks of the rigid backbone of PIMs (such as the spiro structure) are near 700 - 900 cm-1, indicating the successful synthesis of the self-polymerized microporous polymer.

[0070] Figure 4 Figure 4 is the thermogravimetric curve of the self-polymerized microporous polymer prepared in Example 1. As Figure 3 shown, it mainly includes two weight loss processes. Among them, the mass loss of PIM at 50 - 120 °C is 5%, mainly due to the loss of surface organic solvents. Then, starting from 480 °C, 30% of PIM decomposes, causing the structure to collapse. This thermogravimetric result indicates that PIM has relatively high thermal stability.

[0071] Figure 5 Figure 5 is a schematic diagram of the process for preparing the hollow fiber ultrafiltration membrane in Example 1, showing the production process of the membrane filaments. The inner and outer diameter dimensions of the membrane filaments are precisely measured by a computer-controlled automatic size analyzer. This automated system can monitor the size changes of the membrane filaments in real time and ensure that each membrane filament meets the design requirements during the preparation process through high-precision measurement techniques, thus ensuring the uniformity and performance stability of the membrane. Through this precise measurement method, the overall quality of the hollow fiber ultrafiltration membrane can be effectively improved, and the filtration efficiency and anti-fouling performance of the membrane can be ensured to reach the optimal level.

[0072] Figure 6 SEM image of the inner surface of the hollow fiber ultrafiltration membrane prepared in Example 1, as shown in Figure 6 The inner surface of the hollow fiber of this ultrafiltration membrane is a dense structure.

[0073] Figure 7 SEM image of the cross-section of the hollow fiber ultrafiltration membrane prepared in Example 1, as shown in Figure 7 It shows that its interior presents a porous network with a uniform pore distribution, forming a sponge-like fine pore structure, which can effectively increase the membrane surface area and improve the separation performance while maintaining a low fluid resistance.

[0074] Figure 8 Contact angle image of the hollow fiber ultrafiltration membrane prepared in Example 1, as shown in Figure 8 The contact angle of the inner surface of the microporous polymer is 58°, indicating that this ultrafiltration membrane has good hydrophilicity. The smaller contact angle means that water molecules can more easily contact the membrane surface, thus improving the hydrophilicity of the membrane, which plays an important role in enhancing the performance of the ultrafiltration membrane.

[0075] Example 2

[0076] The difference from Example 1 is only that: spinning solution formulation: self-polymerized microporous polymer 25wt%, diethylene glycol 8wt%, tetrahydrofuran 67wt%.

[0077] Others are the same as Example 1.

[0078] The inner diameter of the self-polymerized microporous polymer hollow fiber ultrafiltration membrane prepared in this example is 0.7 mm, the outer diameter is 1.2 mm, and the permeability coefficient is 170 Lm -2 h -1 .

[0079] Example 3

[0080] The difference from Example 1 is only that: spinning solution formulation: self-polymerized microporous polymer 30wt%, diethylene glycol 8wt%, tetrahydrofuran 62wt%.

[0081] Others are the same as Example 1.

[0082] The inner diameter of the self-polymerized microporous polymer hollow fiber ultrafiltration membrane prepared in this example is 0.8 mm, the outer diameter is 1.3 mm, and the permeability coefficient is 198 Lm -2 h -1 .

[0083] Example 4

[0084] The difference from Example 1 is only that: Spinning solution formulation: self-polymerized microporous polymer 22 wt%, diethylene glycol 10 wt%, tetrahydrofuran 68 wt%.

[0085] Other conditions are the same as in Example 1.

[0086] The inner diameter of the self-polymerized microporous polymer hollow fiber ultrafiltration membrane prepared in this example is 0.8 mm, the outer diameter is 1.3 mm, and the permeability coefficient is 178 Lm -2 h -1 。

[0087] Example 5

[0088] The difference from Example 1 is only that: Spinning solution formulation: self-polymerized microporous polymer 22 wt%, diethylene glycol 8 wt%, tetrahydrofuran 70 wt%.

[0089] Core liquid formulation: water and glycerol are mixed according to the mass percentage of 60:40.

[0090] Other conditions are the same as in Example 1.

[0091] The inner diameter of the self-polymerized microporous polymer hollow fiber ultrafiltration membrane prepared in this example is 0.8 mm, the outer diameter is 1.3 mm, and the permeability coefficient is 188 Lm -2 h -1 。

[0092] Example 6

[0093] The difference from Example 1 is only that: Spinning solution formulation: self-polymerized microporous polymer 22 wt%, diethylene glycol 8 wt%, tetrahydrofuran 70 wt%.

[0094] Core liquid formulation: water and glycerol are mixed according to the mass percentage of 40:60.

[0095] Other conditions are the same as in Example 1.

[0096] The inner diameter of the self-polymerized microporous polymer hollow fiber ultrafiltration membrane prepared in this example is 0.8 mm, the outer diameter is 1.3 mm, and the permeability coefficient is 195 Lm -2 h -1 。

[0097] Example 7

[0098] The difference from Example 1 is only that:

[0099] At room temperature, the spinning solution is extruded through the spinneret holes of the casting solution, and at the same time, the core liquid is injected through the core liquid holes. The extruded membrane filaments vertically fall into a coagulation bath (deionized water) at 30 °C, the coagulation time is 10 minutes, and after forming, the filaments are collected by a wire collecting device and dried to obtain a self-polymerized microporous polymer hollow fiber ultrafiltration membrane.

[0100] Others are the same as in Example 1.

[0101] The inner diameter of the self - polymerized microporous polymer hollow fiber ultrafiltration membrane prepared in this example is 0.8 mm, the outer diameter is 1.3 mm, and the permeability coefficient is 106 Lm -2 h -1 。

[0102] Example 8

[0103] The difference from Example 1 is only that:

[0104] At room temperature, the spinning solution is extruded through the spinneret holes of the casting solution, and at the same time, the core liquid is injected through the core liquid holes. The extruded membrane filaments vertically fall into a coagulation bath (deionized water) at 20 °C, the coagulation time is 15 minutes, and after forming, the filaments are collected by a wire - collecting device and dried to obtain a self - polymerized microporous polymer hollow fiber ultrafiltration membrane.

[0105] Others are the same as in Example 1.

[0106] The inner diameter of the self - polymerized microporous polymer hollow fiber ultrafiltration membrane prepared in this example is 0.8 mm, the outer diameter is 1.3 mm, and the permeability coefficient is 185 Lm -2 h -1 。

[0107] The above - mentioned are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a self-polymerized microporous polymer hollow fiber ultrafiltration membrane, characterized in that: The following steps are involved: The self-polymerizing microporous polymer, a plasticizer and an organic solvent are mixed to obtain a spinning solution; Mix water and glycerin to obtain core liquid; The spinning solution and the core solution are wet-spinned and then coagulated in a coagulation bath to obtain a self-polymerized microporous polymer hollow fiber ultrafiltration membrane; The monomers for preparing the self-polymerized microporous polymer include tetrafluoroterephthalonitrile and 5,5',6,6'-tetrahydroxy-3,3',3,3'-tetramethyl spirobiindene.

2. The preparation method according to claim 1, characterized in that: The plasticizer includes diethylene glycol, glycerol, polydimethylsiloxane or dioctyl phthalate; the organic solvent includes tetrahydrofuran, chloroform or N,N-dimethylacetamide.

3. The preparation method according to claim 1 or 2, characterized in that: The contents of the components in the spinning solution are: 22-30 wt % of self-polymerized microporous polymer, 7-10 wt % of plasticizer, and 60-70 wt % of organic solvent.

4. The preparation method according to claim 1, characterized in that: The mass ratio of water to glycerol in the core liquid is 80:20 to 20:

80.

5. The preparation method according to claim 1, characterized in that: The method for preparing the self-polymerized microporous polymer comprises the following steps: Tetrafluoroterephthalonitrile, 5,5',6,6'-tetrahydroxy-3,3',3,3'-tetramethyl spirobiindene, potassium carbonate and N,N-dimethylacetamide are mixed, subjected to polymerization reaction, and then precipitated, treated with boiling water and vacuum dried in sequence to obtain a self-polymerized microporous polymer.

6. The preparation method according to claim 5, characterized in that: The molar concentration of tetrafluoroterephthalonitrile in N,N-dimethylacetamide is 10-30 mmol / L, the molar concentration of 5,5',6,6'-tetrahydroxy-3,3',3,3'-tetramethyl spirobisindene in N,N-dimethylacetamide is 15-50 mmol / L, and the molar concentration of potassium carbonate in N,N-dimethylacetamide is 50-100 mmol / L.

7. The preparation method according to claim 6, characterized in that: The polymerization reaction is carried out at a temperature of 100 to 200° C. and for a time of 30 to 60 minutes.

8. The self-polymerized microporous polymer hollow fiber ultrafiltration membrane prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The inner diameter is 0.5~0.8mm, and the outer diameter is 1.0~1.3mm.

9. The self-polymerized microporous polymer hollow fiber ultrafiltration membrane according to claim 8, characterized in that: At 0.1 MPa, the permeability coefficient of the self-polymerized microporous polymer hollow fiber ultrafiltration membrane is >100 Lm -2 h -1 .

10. Use of the self-polymerizing microporous polymer hollow fiber ultrafiltration membrane according to claim 8 or 9 in the fields of water treatment, food separation or pharmaceutical separation.

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