A surface-coated in-situ modified hollow fiber membrane material and its preparation method

Abstract

This invention provides a surface-coated in-situ modified hollow fiber membrane material and its preparation method. The preparation method includes the following steps: Step 1, preparing a casting solution; the casting solution is used to prepare a hollow fiber membrane precursor through a spinning process; Step 2, the hollow fiber membrane precursor is sequentially passed through an air gap, a cooling tank, and a solvent exchange tank to obtain a semi-finished membrane; the coolant in the cooling tank is a plasma-treated ethylene glycol aqueous solution; Step 3, the semi-finished membrane is further surface-treated with plasma to obtain a hollow fiber membrane containing a surface polyethylene glycol coating structure. This invention fully utilizes the components of the coolant and combines it with plasma polymerization treatment to perform in-situ modification on the surface of the hollow fiber membrane, rapidly and efficiently forming a polyethylene glycol coating on the surface of the hollow fiber membrane.

Description

Technical Field

[0001] This invention belongs to the field of material surface modification technology, and specifically provides a surface coating in-situ modified hollow fiber membrane material and its preparation method. Background Technology

[0002] The composition and structure of the material surface are important factors determining the application effect of hollow fiber membranes. Hollow fiber membranes used in membrane oxygenators as blood contact materials need to have stable chemical and mechanical properties, good leak-proof performance, blood compatibility, and good gas exchange performance. These characteristics can improve the service life and efficiency of blood gas exchange membranes and reduce a series of immune reactions such as hemolysis and coagulation.

[0003] When hollow fiber membrane materials come into direct contact with blood as foreign substances, they rapidly trigger a series of reactions, affecting the human coagulation and immune systems, ultimately leading to thrombosis or hemolysis. Therefore, improving the blood compatibility of membrane materials is extremely important. Modern research and development of hollow fiber membrane materials for membrane oxygenators focuses on surface coatings. By coating the fiber surface with materials possessing good oxygen permeability and anticoagulant properties, the efficiency of artificial lungs can be improved. Simultaneously, the thin and dense surface layer, in contact with blood, prevents plasma permeation, allowing for long-term clinical application. Currently, various technologies and methods have been developed to prepare coatings on the surface of hollow fiber membranes. However, existing immersion coating methods also have drawbacks, such as complex coating solution composition, long immersion times, the need for fiber membrane pretreatment, and the inability to couple with existing hollow fiber membrane preparation equipment. Summary of the Invention

[0004] To address the aforementioned problems in existing technologies, the present invention aims to propose a technique for preparing hollow fiber membranes with surface coatings by adjusting the cooling and post-processing processes. This technique fully utilizes the coolant used in the hollow fiber membrane preparation process and combines it with plasma polymerization treatment to achieve in-situ formation of a polyethylene glycol coating on the surface of the hollow fiber membrane, thereby obtaining a hollow fiber membrane material with in-situ modified surface coating.

[0005] The purpose of this invention is to improve the cooling process in the preparation of hollow fiber membranes by thermally induced phase separation (TIPS) by using an aqueous solution of ethylene glycol that has been treated with plasma. This effectively cools the fiber membrane while simultaneously using subsequent plasma polymerization to polymerize the ethylene glycol components into polyethylene glycol-like structures, thereby rapidly and efficiently forming a coating on the surface of the hollow fiber membrane.

[0006] The first aspect of this invention provides a method for preparing a surface-coated in-situ modified hollow fiber membrane material, the method comprising the following steps:

[0007] Step 1: Prepare a casting solution containing polyolefin material and diluent. The casting solution is used to prepare hollow fiber membrane precursor through a spinning process.

[0008] Step 2: The hollow fiber membrane precursor is passed sequentially through an air gap, a cooling tank, and a solvent exchange tank to obtain a semi-finished membrane after the diluent has been removed; the coolant in the cooling tank is an ethylene glycol aqueous solution that has been treated with plasma.

[0009] Step 3: Place the cooled semi-finished membrane under plasma for polymerization treatment to obtain a hollow fiber membrane with in-situ modified surface coating.

[0010] Furthermore, the polyolefin material content in the casting solution is 20wt% to 50wt%, and the diluent content is 50wt% to 80wt%.

[0011] Furthermore, the polyolefin material is selected from poly-4-methyl-1-pentene or polypropylene.

[0012] Further, the diluent is selected from at least one of dioctyl phthalate, glyceryl triacetate, dibutyl phthalate, and dioctyl phthalate.

[0013] Further, in step 1, the spinning process involves extruding the casting solution through a spinneret to form hollow fibers, wherein the difference between the outer diameter and the inner diameter of the spinneret is 5 μm to 500 μm. Preferably, the difference between the outer diameter and the inner diameter of the spinneret is 150 μm to 500 μm.

[0014] Further, the inner diameter of the spinneret is 50μm to 500μm, and the outer diameter of the spinneret is 100μm to 1000μm. Preferably, the inner diameter of the spinneret is 100μm to 300μm, and the outer diameter of the spinneret is 200μm to 800μm.

[0015] Furthermore, the air gap is 10mm to 500mm. Preferably, the air gap is 50mm to 300mm.

[0016] Furthermore, the extrusion spinning speed is 20 m / min to 200 m / min. Preferably, the extrusion spinning speed is 20 m / min to 80 m / min.

[0017] Furthermore, the coolant in the cooling pool is selected from an ethylene glycol aqueous solution that has undergone plasma treatment; the temperature of the cooling pool is 25℃ to 66℃. The ethylene glycol content in the ethylene glycol aqueous solution is 50% to 80%.

[0018] Furthermore, the coolant is an activated solution produced by treating an aqueous ethylene glycol solution using atmospheric pressure plasma technology, with the atmospheric pressure plasma treatment time ranging from 20 to 180 minutes, preferably from 30 to 120 minutes.

[0019] Further, in step 2, the solvent exchange tank is provided with an extractant, and the diluent is removed by extraction with the extractant; the extractant is selected from at least one of ethanol, isopropanol, N,N-dimethylformamide, ethyl acetate, amyl acetate, dichloromethane and ethylene glycol butyl ether.

[0020] Furthermore, in step 3, the plasma is generated by the discharge of nitrogen and oxygen, with a gas ratio of 1:0.01 to 1:0.1, and the plasma treatment time is 10 min to 45 min.

[0021] The second aspect of the present invention provides a surface-coated in-situ modified hollow fiber membrane material prepared by the above preparation method.

[0022] The third aspect of the present invention provides the use of the above-mentioned surface-coated in-situ modified hollow fiber membrane material, wherein the surface-coated in-situ modified hollow fiber membrane material prepared by the above preparation method is used as a medium for blood gas exchange during extracorporeal membrane oxygenation.

[0023] Beneficial effects

[0024] Compared with existing technologies, this invention makes full use of the key role of the cooling process in the spinning process. By designing and screening the cooling liquid, the activity of the ethylene glycol aqueous solution is activated by plasma. While ensuring the cooling of the hollow fiber membrane, the surface of the hollow fiber membrane is activated and modified. The subsequent plasma polymerization treatment forms a polyethylene glycol coating, thereby forming a coating on the surface of the hollow fiber membrane quickly and efficiently. Attached Figure Description

[0025] Figure 1 Electron microscope images of hollow fiber membranes obtained using the conventional method in Comparative Example 1.

[0026] Figure 2 Electron microscope images of hollow fiber membranes were obtained using the method described in Example 1 of this invention.

[0027] Figure 3 The image shows the infrared spectrum of the hollow fiber membrane obtained using the conventional method in Comparative Example 1.

[0028] Figure 4 The image shows the infrared spectrum of the hollow fiber membrane obtained using the method described in Example 1 of this invention. Detailed Implementation

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but this should not be construed as limiting the scope of the present invention.

[0030] The technical solution of the present invention does not limit the structure of the cooling pool for impregnation with cooling liquid and the structure of the solvent exchange pool, because those skilled in the art can design the above-mentioned device according to specific experimental needs under the condition of hollow fiber membrane spinning and forming.

[0031] This invention does not limit the plasma generating device for plasma-activated ethylene glycol solution, because those skilled in the art, given the discharge gas and the target to be treated, can design atmospheric pressure plasma generating devices such as plasma jets and dielectric barrier discharges according to specific experimental needs. Furthermore, this invention does not limit the plasma discharge power, as different discharge devices produce different discharge powers. Those skilled in the art can adjust the discharge power based on the generating device, gas flow rate, and the condition of the solution to be treated, as long as the desired effect is achieved.

[0032] Some specific embodiments of the present invention provide a method for preparing a surface-coated in-situ modified hollow fiber membrane material, the preparation method comprising the following steps:

[0033] Step 1: Melt the polyolefin material and diluent in a twin-screw extruder, stir, degas, and then obtain a casting solution. Extrude the casting solution through a spinneret to form a hollow fiber membrane precursor; the total content of the polyolefin material and diluent is 100%.

[0034] In some specific embodiments, in step 1, the content of polyolefin material in the casting solution is 20 wt% to 50 wt%, and the content of diluent is 50 wt% to 80 wt%. For example, the content of polyolefin material is 20 wt% and the content of diluent is 80 wt%; the content of polyolefin material is 30 wt% and the content of diluent is 70 wt%; the content of polyolefin material is 40 wt% and the content of diluent is 60 wt%; the content of polyolefin material is 50 wt% and the content of diluent is 50 wt%.

[0035] In some specific implementations, in step 1, the polyolefin material is selected from poly-4-methyl-1-pentene or polypropylene.

[0036] In some specific implementations, in step 1, the diluent is selected from at least one of dioctyl phthalate, glyceryl triacetate, dibutyl phthalate, and dioctyl phthalate.

[0037] In some specific implementations, in step 2, the difference between the outer diameter and the inner diameter of the spinneret is 150 μm to 500 μm. For example, it is 200 μm, 300 μm, or 400 μm.

[0038] In some specific implementations, the inner diameter of the spinneret is 100μm to 300μm, for example, 200μm; the outer diameter of the spinneret is 200μm to 800μm, for example, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, or 800μm.

[0039] In some specific embodiments, the extrusion spinning speed is 20 m / min to 200 m / min. Preferably, the extrusion spinning speed is 20 m / min to 80 m / min. For example, it is 30 m / min, 40 m / min, 50 m / min, 60 m / min, or 70 m / min.

[0040] In some specific embodiments, the casting solution is obtained by melting, stirring, and degassing polyolefin materials and diluents in a twin-screw extruder.

[0041] Step 2: The hollow fiber membrane precursor is passed sequentially through an air gap, a cooling tank, and a solvent exchange tank to obtain a semi-finished membrane after the diluent has been removed; the coolant in the cooling tank is an ethylene glycol aqueous solution that has been treated with plasma.

[0042] In some specific embodiments, the gas in the air gap is at least one selected from air, nitrogen, and carbon dioxide, and the air gap is 50 mm to 300 mm, for example, 100 mm or 200 mm.

[0043] Furthermore, the coolant in the cooling pool is selected from an ethylene glycol aqueous solution that has undergone plasma treatment; the temperature of the cooling pool is 25°C to 66°C, for example, 30°C, 40°C, 50°C, or 60°C. The ethylene glycol content in the ethylene glycol aqueous solution is 50% to 80%, for example, 60% or 70%.

[0044] Furthermore, the coolant is an activated solution produced by treating an aqueous ethylene glycol solution using atmospheric pressure plasma technology. The atmospheric pressure plasma treatment time is 20 min to 180 min, preferably 30 min to 120 min, for example, 30 min, 40 min, 50 min, 60 min, 80 min, 100 min, 120 min, 140 min, or 160 min.

[0045] In some specific implementations, in step 2, the solvent exchange tank is provided with an extractant to remove the diluent through extraction with the extractant; the extractant is selected from at least one of ethanol, isopropanol, N,N-dimethylformamide, ethyl acetate, amyl acetate, dichloromethane, and ethylene glycol butyl ether.

[0046] Step 3: Place the cooled semi-finished membrane under plasma for polymerization treatment to obtain a hollow fiber membrane with in-situ modified surface coating.

[0047] Furthermore, in step 3, the plasma is generated by the discharge of nitrogen and oxygen, with a gas ratio of 1:0.01 to 1:0.1, and the plasma treatment time is 10 min to 45 min, for example, 15 min, 20 min, 25 min, 30 min, 35 min, and 40 min.

[0048] The method of the present invention uses a special coolant to replace the conventional coolant of the thermally induced phase separation (TIPS) method, so that the hollow fiber membrane precursor is activated by the plasma solution during the cooling process, thereby forming a coating on the surface of the hollow fiber membrane quickly and efficiently.

[0049] The hollow fiber membrane obtained by the preparation method of the present invention has a stable and uniform coating and is prepared rapidly, and can be used on a large scale as a medium for blood gas exchange in extracorporeal membrane oxygenation.

[0050] Example 1

[0051] Step 1: Melt, stir, and degas the raw material containing 30 wt% poly4-methyl-1-pentene and 70 wt% dibutyl phthalate in a twin-screw extruder to obtain a casting solution; spun the casting solution through a spinneret with an inner diameter of 100 μm and an outer diameter of 500 μm at a spinning speed of 40 m / min to obtain a hollow fiber membrane precursor;

[0052] Step 2: The hollow fiber membrane precursor is sequentially passed through an air gap, a cooling tank, and a solvent exchange tank to obtain a semi-finished membrane after the diluent has been removed. The coolant in the cooling tank is a plasma-treated ethylene glycol aqueous solution at a temperature of 25°C. The ethylene glycol aqueous solution contains 50% ethylene glycol, and the plasma treatment is atmospheric pressure plasma treatment for 30 minutes. The air gap is 100 mm wide, and the gas in the air gap is air. The extractant in the solvent exchange tank is ethanol.

[0053] Step 3: The cooled semi-finished membrane is placed under plasma for polymerization treatment to obtain a hollow fiber membrane with in-situ modified surface coating. The plasma is generated by the discharge of nitrogen and oxygen in a gas ratio of 1:0.01, and the plasma treatment time is 30 minutes.

[0054] Example 2

[0055] Step 1: Melt, stir, and degas the raw material containing 30% poly-4-methyl-1-pentene and 70% triacetylglycerol in a twin-screw extruder to obtain a casting solution; spun the casting solution through a spinneret with an inner diameter of 200 μm and an outer diameter of 600 μm at a spinning speed of 40 m / min to obtain a hollow fiber membrane precursor;

[0056] Step 2: The hollow fiber membrane precursor is sequentially passed through an air gap, a cooling tank, and a solvent exchange tank to obtain a semi-finished membrane after the diluent has been removed. The coolant in the cooling tank is a plasma-treated ethylene glycol aqueous solution at a temperature of 50°C. The ethylene glycol aqueous solution contains 80% ethylene glycol, and the atmospheric pressure plasma treatment time is 40 minutes. The air gap is 200 mm wide, and the gas in the air gap is air. The extractant in the solvent exchange tank is isopropanol.

[0057] Step 3: The cooled semi-finished membrane is subjected to plasma polymerization treatment to obtain a hollow fiber membrane with in-situ modified surface coating. The plasma is generated by nitrogen and oxygen discharge in a ratio of 1:0.05, and the plasma treatment time is 40 minutes.

[0058] Example 3

[0059] Step 1: The raw material containing 35% poly-4-methyl-1-pentene and 75% dioctyl phthalate is melted, stirred, and degassed in a twin-screw extruder to obtain a casting solution; the casting solution is then spun out through a spinneret with an inner diameter of 300 μm and an outer diameter of 800 μm at a spinning speed of 40 m / min to obtain a hollow fiber membrane precursor;

[0060] Step 2: The hollow fiber membrane precursor is sequentially passed through an air gap, a cooling tank, and a solvent exchange tank to obtain a semi-finished membrane after the diluent has been removed. The coolant in the cooling tank is a plasma-treated ethylene glycol aqueous solution at a temperature of 40°C. The ethylene glycol aqueous solution contains 70% ethylene glycol, and the atmospheric pressure plasma treatment time is 90 minutes. The air gap is 300 mm wide, and the gas in the air gap is air. The extractant in the solvent exchange tank is ethyl acetate.

[0061] Step 3: The cooled semi-finished membrane is subjected to plasma polymerization treatment to obtain a hollow fiber membrane with in-situ modified surface coating. The plasma is generated by the discharge of nitrogen and oxygen in a gas ratio of 1:0.06, and the plasma treatment time is 40 minutes.

[0062] Example 4

[0063] Step 1: Dissolve, stir, and degas the raw material containing 40% poly-4-methyl-1-pentene and 60% triacetylglycerol in a twin-screw extruder to obtain a casting solution; spun the casting solution through a spinneret with an inner diameter of 200 μm and an outer diameter of 600 μm at a spinning speed of 40 m / min to obtain a hollow fiber membrane precursor;

[0064] Step 2: The hollow fiber membrane precursor is sequentially passed through an air gap, a cooling tank, and a solvent exchange tank to obtain a semi-finished membrane after the diluent has been removed. The coolant in the cooling tank is a plasma-treated ethylene glycol aqueous solution at a temperature of 60°C. The ethylene glycol aqueous solution contains 65% ethylene glycol, and the atmospheric pressure plasma treatment time is 100 min. The air gap is 200 mm, and the gas in the air gap is nitrogen. The extractant in the solvent exchange tank is dichloromethane.

[0065] Step 3: The cooled semi-finished membrane is placed under plasma for polymerization treatment to obtain a hollow fiber membrane with in-situ modified surface coating. The plasma is generated by the discharge of nitrogen and oxygen in a gas ratio of 1:0.08, and the plasma treatment time is 35 minutes.

[0066] Example 5

[0067] Step 1: Dissolve, stir, and degas the raw material containing 20% ​​polypropylene and 80% dioctyl oxalate in a twin-screw extruder to obtain a casting solution; spray the casting solution through a spinneret with an inner diameter of 50 μm and an outer diameter of 200 μm at a spinning speed of 35 m / min to obtain a hollow fiber membrane precursor.

[0068] Step 2: The hollow fiber membrane precursor is sequentially passed through an air gap, a cooling tank, and a solvent exchange tank to obtain a semi-finished membrane after the diluent has been removed. The coolant in the cooling tank is a plasma-treated ethylene glycol aqueous solution at a temperature of 45°C. The ethylene glycol aqueous solution contains 55% ethylene glycol, and the atmospheric pressure plasma treatment time is 120 minutes. The air gap is 50 mm, and the gas in the air gap is nitrogen. The solvent in the solvent exchange tank is N,N-dimethylformamide.

[0069] Step 3: The cooled semi-finished membrane is subjected to plasma polymerization treatment to obtain a hollow fiber membrane with in-situ modified surface coating. The plasma is generated by nitrogen and oxygen discharge in a gas ratio of 1:0.09, and the plasma treatment time is 35 minutes.

[0070] Comparative Example 1

[0071] The same method as in Example 1 is used, except that conventional water is used as the coolant.

[0072] Effect Experiment

[0073] First, the surface and cross-section of the hollow fiber were observed using a scanning electron microscope. Figure 1 The image shown is a scanning electron microscope image of the poly(4-methyl-1-pentene) hollow fiber membrane obtained using conventional water cooling liquid in Comparative Example 1. It can be seen that the outer skin of the hollow fiber membrane is smooth and flat, while the cross-section shows a distinctly rough morphology.

[0074] Scanning electron microscope images of the hollow fiber membrane obtained in Example 1 are shown below. Figure 2 As shown, compared with conventional processes, the method of this invention does not affect the morphology of the inner skin layer, thus ensuring the mechanical properties and permeability of the membrane fibers. However, the outer skin layer of the fiber membrane exhibits a relatively rough coating morphology, confirming the successful preparation of hollow fiber membranes with in-situ surface coating modification.

[0075] Furthermore, the hollow fiber membranes obtained in Example 1 and Comparative Example 2 were compared using infrared spectroscopy. Comparative Example 1 ( Figure 3 The infrared spectrum of the hollow fiber membrane obtained (as shown) is that of a conventional poly4-methyl-1-pentene hollow fiber membrane, and it does not possess any other characteristic peaks. By comparison, it can be seen that Example 1 ( Figure 4 (As shown) The hollow fiber membrane prepared by the method of the present invention retains the characteristic peaks of conventional fiber membranes, and also exhibits peaks at 1550 cm⁻¹. -1 ~1750cm -1 The presence of characteristic peaks such as C=O, CN, and CC confirms the presence of polyethylene glycol components, indicating that the method of this invention can form polyethylene glycol structures in situ on the surface of hollow fiber membranes. These results demonstrate that this method yields a hollow fiber membrane material with in-situ modified surface coating.

Claims

1. A method for preparing a surface-coated in-situ modified hollow fiber membrane material, characterized in that, The preparation method includes the following steps: Step 1: Prepare a casting solution containing polyolefin material and diluent. The casting solution is used to prepare hollow fiber membrane precursor through a spinning process. Step 2: The hollow fiber membrane precursor is passed sequentially through an air gap, a cooling tank, and a solvent exchange tank to obtain a semi-finished membrane after the diluent has been removed; the coolant in the cooling tank is an ethylene glycol aqueous solution that has been treated with plasma. Step 3: The cooled semi-finished membrane is subjected to plasma polymerization treatment to obtain a hollow fiber membrane with in-situ modified surface coating; The coolant is an activated solution produced by treating an aqueous ethylene glycol solution using atmospheric pressure plasma technology, with the atmospheric pressure plasma treatment time ranging from 20 min to 180 min.

2. The preparation method according to claim 1, characterized in that, The casting solution contains 20 wt% to 50 wt% polyolefin material and 50 wt% to 80 wt% diluent.

3. The preparation method according to claim 2, characterized in that, The polyolefin material is selected from poly-4-methyl-1-pentene or polypropylene.

4. The preparation method according to claim 2, characterized in that, The diluent is selected from at least one of dioctyl phthalate, glyceryl triacetate, dibutyl phthalate, and dioctyl phthalate.

5. The preparation method according to claim 1, characterized in that, In step 1, the spinning process involves extruding the casting solution through a spinneret to form hollow fibers. The difference between the outer diameter and the inner diameter of the spinneret is 5 μm to 500 μm.

6. The preparation method according to claim 5, characterized in that, In step 1, the difference between the outer diameter and the inner diameter of the spinneret is 150μm to 500μm.

7. The preparation method according to claim 5, characterized in that, The inner diameter of the spinneret is 50 μm to 500 μm, and the outer diameter of the spinneret is 100 μm to 1000 μm.

8. The preparation method according to claim 5, characterized in that, The inner diameter of the spinneret is 100μm to 300μm, and the outer diameter of the spinneret is 200μm to 800μm.

9. The preparation method according to claim 1, characterized in that, The air gap is 10 mm to 500 mm; the gas in the air gap is selected from at least one of air, nitrogen, and carbon dioxide.

10. The preparation method according to claim 9, characterized in that, The air gap is 50 mm to 300 mm.

11. The preparation method according to claim 5, characterized in that, The extrusion spinning speed is 20 m / min to 200 m / min.

12. The preparation method according to claim 11, characterized in that, The extrusion spinning speed is 20 m / min to 80 m / min.

13. The preparation method according to claim 1, characterized in that, The temperature of the cooling pool is 25℃~66℃.

14. The preparation method according to claim 13, characterized in that, The ethylene glycol aqueous solution contains 50% to 80% ethylene glycol.

15. The preparation method according to claim 1, characterized in that, In step 2, the solvent exchange tank is provided with an extractant, and the diluent is removed by extraction with the extractant; the extractant is selected from at least one of ethanol, isopropanol, N,N-dimethylformamide, ethyl acetate, amyl acetate, dichloromethane and ethylene glycol butyl ether.

16. The preparation method according to claim 1, characterized in that, In step 3, the plasma is generated by the discharge of nitrogen and oxygen, with a gas ratio of 1:0.01 to 1:0.1, and the plasma treatment time is 10 min to 45 min.

17. The surface-coated in-situ modified hollow fiber membrane material prepared by the preparation method according to any one of claims 1-16.

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