Polyethersulfone hollow fiber blend membrane with polydopamine attached to inner surface and preparation method of polyether sulfone hollow fiber blend membrane

Abstract

The invention discloses a polyether sulfone hollow fiber blend membrane with polydopamine attached to the inner surface and a preparation method of the polyether sulfone hollow fiber blend membrane. The polyether sulfone hollow fiber blend membrane comprises the following raw material components: 10-20 wt% of polyether sulfone, 1-3 wt% of polydopamine, 5-10 wt% of a pore-foaming agent and 60-85 wt% of an organic solvent. The outer diameter of the hollow fiber membrane is 0.1-50 mm, the inner diameter of the hollow fiber membrane is 0.1-50 mm, the micropore diameter of the hollow fiber membrane is 0.01 mu m-1mm, and the porosity of the hollow fiber membrane is 50-95%; the invention has the following beneficial effects: the film can resist steam sterilization; and moreover, good hydrophilicity is achieved, and waste can be biodegraded.

Description

Technical Field

[0001] The present invention relates to the technical field of hemodialysis, in particular to a polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface thereof and a preparation method thereof. Background Art

[0002] Hemodialysis has a history of more than 90 years. Dialysis membrane materials have evolved from copper-based membranes, regenerated cellulose membranes, and modified cellulose membranes to artificial synthetic membranes. Synthetic membranes are high-molecular polymers with good biocompatibility and are available in many varieties. Currently, commonly used synthetic membrane materials include polysulfone (PS), polyacrylonitrile (PAN), polyamide (PA), polycarbonate membrane (PC), polyethersulfone (PES), polymethyl methacrylate membrane (PMMA), and cellulose acetate (CA). These membrane materials are widely used, with polysulfone being the most widely used due to its excellent mechanical properties, stable physicochemical properties, high solute permeability, high clearance rate for middle-molecular toxins, and its low price and availability. However, the current advanced hemodialyzer sterilization method uses water vapor, and the pore structure of polysulfone porous membranes can change after long-term use at 80°C, making them unsuitable for 138°C steam sterilization. Polyethersulfone has a Tg of up to 223°C and can be used for long periods at 140°C, making it the preferred hemodialysis membrane material resistant to steam sterilization.

[0003] Although today's artificial kidneys have greatly improved in both structure and function, they are still far behind the human kidney. In particular, some membrane materials require the use of heparin after hemodialysis. Long-term use of heparin not only increases the financial burden but also leads to diseases such as osteoporosis and poor coagulation function.

[0004] In view of the above situation, it is necessary to improve the existing membrane materials so that they can adapt to the current needs of hemodialysis. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface, the raw material components of which include: 10-20wt% of polyethersulfone, 1-3wt% of polydopamine, 5-10wt% of a porogen, and 60-85wt% of an organic solvent; the outer diameter of the hollow fiber membrane is 0.1-50mm, the inner diameter is 0.1-50mm, the micropore diameter is 0.01um-1mm, and the porosity is 50-95%.

[0006] As a further supplement to the present technical solution, the preparation method of polydopamine comprises the following steps:

[0007] Dopamine is oxidized in aqueous solution and undergoes cross-linking reaction to form a polydopamine composite layer rich in catechol groups on the surface of the material. Among them, the catechol active groups can react secondary. Under alkaline conditions, these groups are easily oxidized into quinone structures, thereby undergoing Michael addition and Schiff base reactions with thiol (-SH) molecules; catechol groups are easily oxidized to generate dopamine quinone compounds with catechol structures; dopamine and dopamine quinone undergo an anti-disproportionation reaction to produce semiquinone free radicals, which are then coupled to form cross-linked bonds to form polydopamines with different molecular weights; the preferred molecular weight in this experiment is 50,000-80,000 Daltons.

[0008] As a further supplement to the technical solution, the viscosity-average molecular weight of the polyethersulfone is 40,000 to 120,000; and the molecular weight of the polydopamine is 50,000 to 80,000.

[0009] As a further supplement to the present technical solution, the porogen water-soluble polymer is one of starch, carboxymethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl chitosan, gelatin, polyethylene glycol, polyvinyl alcohol, polyacrylamide, polyacrylic acid, polyethylene oxide, polyethylene imine, and polyvinyl pyrrolidone (PVP).

[0010] As a further supplement to the technical solution, the organic solvent is one of dimethyl sulfoxide, N-methyl-2-pyrrolidone, dimethylamide, and dimethylacetamide.

[0011] A method for preparing a polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface comprises the following steps:

[0012] (1) Polyethersulfone and a porogen are added to an organic solvent, heated and stirred to form a uniform polymer solution, which is filtered and degassed to form a spinning solution; an aqueous solution of polydopamine and a solvent forms a core liquid, wherein polydopamine is 1-3%, an organic solvent is 30-50%, and the remainder is purified water.

[0013] (2) The organic solvent of polyethersulfone and porogen and water are mixed to form a spinning coagulation bath, wherein the weight concentration of the organic solvent is 0 to 20% and the temperature is 0° C. to 70° C.

[0014] To further supplement the present technical solution, the spinning solution is prepared from the following raw materials in weight percentage: 70-80% solvent, 10-20% membrane material, 2-4% PVP, and 0-3% purified water; wherein the solvent is dimethylacetamide (DMAC) and the membrane material is polyethersulfone (PES); the PVP uses 80% PVP, K90 or 20% PVP, K30 to form membrane micropores of appropriate size; wherein 80% PVP, K90 can produce large micropores to remove medium and large molecular toxins; 20% PVP, K30 can produce small micropores to remove water and small molecular toxins, maintain the uniformity of the micropore size, and at the same time maintain a certain pressure difference between the inside and outside of the membrane to avoid blood pressure fluctuations during dialysis.

[0015] As a further supplement to the present technical solution, the method for preparing the spinning solution comprises the following steps:

[0016] (1) PVP, membrane material and 25-30% solvent are mixed and extruded in a screw extruder, mixed evenly to form a preliminary high-viscosity spinning solution; after the extrusion is qualified, it is put into a stirring preparation kettle, 50% solvent and 0-3% purified water are added; it is heated to 60-85℃ to dissolve, dissolved for 6-8 hours, and degassed at a negative pressure of 0.3-0.5 bar for 2-3 hours until the spinning solution is clear and transparent.

[0017] (2) The spinning solution obtained in step (1) is extruded through a spinneret for spinning hollow fiber membranes, and solidified into a polyethersulfone hollow fiber membrane by wet spinning or dry-wet spinning, and polydopamine is attached to the inner surface of the membrane, with an air layer height of 20-50 cm;

[0018] (3) The solidified polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface of the membrane is stretched 1 to 3 times in a water bath at a temperature of 50°C to 99°C; the residual solvent, part of the porogen, and part of the polydopamine are washed away in a water bath at 70°C to 99°C; and the membrane is dried at 80°C to 180°C to obtain the polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface.

[0019] The beneficial effects are as follows: (1) the polyethersulfone of the main material of the polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface prepared by the present invention is resistant to steam sterilization, which is conducive to the use of advanced methods for sterilization of artificial kidney dialyzers;

[0020] (2) The polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface prepared by the present invention contains a certain amount of polydopamine with high biocompatibility and a water-soluble polymer porogen, which can improve the hydrophilicity and biocompatibility of the membrane;

[0021] (3) The modified material polydopamine of the polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface prepared by the present invention has good anti-coagulant properties, reduces the adsorption and deposition of coagulation factors, platelets and proteins on the membrane surface, improves the anti-pollution ability of the membrane, stabilizes the dialysis rate, and does not increase the dialysis pressure; with the continuous hemodialysis filter prepared by the present invention, patients do not need to use or use less heparin, and can be treated continuously for 24 hours, thereby avoiding the need for patients to replace the hemodialysis filter every 4-6 hours during hemodialysis treatment. At the same time, the present invention also reduces the cost of hemodialysis and alleviates the burden on patients with kidney disease. DETAILED DESCRIPTION

[0022] In order to make the technical solution more clear to those skilled in the art, the technical solution of the present invention will be described in detail below with reference to embodiments:

[0023] Example 1

[0024] Prepare the following ingredients by weight percentage: 15% polyethersulfone, 75% dimethylacetamide, and 10% PVP (K30 + K90). Preliminary mixing of the solvent and solids is performed in a screw extruder. Add the ingredients to a container, heat to 70°C, and stir to dissolve the resulting solution. Filter the solution and vacuum degas for 5 hours. The spinning solution is then placed in a barrel equipped with a heating and insulation function and maintained at 70°C. The core liquid formulation consists of 1% polydopamine, 50% dimethylacetamide, and the remainder purified water. The spinning solution is extruded through a spinneret for spinning hollow fiber membranes and solidified and formed using a dry-wet spinning process. The parameters are: an air layer height of 40 cm, a coagulation bath water temperature of 50°C; a single-stage stretching, a water bath as a stretching medium, a water bath temperature of 80°C, and a stretching ratio of 1.5 times; then the solvent and part of the porogen are removed in 80°C water, the membrane is dried under nitrogen protection, and sterilized to obtain a polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface; the hollow fiber membrane has an outer diameter of 0.3 mm, an inner diameter of 0.05 mm, a micropore diameter of 10-15 nm, and a porosity of 70-80%.

[0025] Example 2

[0026] The ingredients are prepared according to the following components and mass percentages: 15% polyethersulfone, 10% polyethylene glycol (molecular weight 10,000), and 75% dimethyl sulfoxide. First, preliminarily mix some of the solvent and solids in a screw extruder. Add the above raw materials to a container, heat to 75°C, stir and dissolve to form a solution, filter the solution, and vacuum degas for 5 hours. Load the spinning solution into a barrel with heating and heat preservation functions and maintain the temperature at 75°C. The core liquid formula is 2% polydopamine, 45% dimethyl sulfoxide, and the rest is purified water. Dimethyl sulfoxide and water are mixed to form a spinning coagulation bath with a weight concentration of dimethyl sulfoxide of 2%. Extrude through a spinneret for spinning hollow fiber membranes and solidify and form using a dry-wet spinning process. The parameters are: air layer height 45 cm, coagulation bath is a dimethyl sulfoxide aqueous solution with a dimethyl sulfoxide weight concentration of 2%, and temperature 50°C. The stretching process is performed in two stages, using a water bath at 80°C as the stretching medium and a stretching ratio of 4. The solvent, part of the porogen, and part of the polydopamine are then removed in 80°C water. The membrane is then air-dried and sterilized to produce a polyethersulfone hollow fiber blend membrane with polydopamine attached to its inner surface. The hollow fiber membrane has an outer diameter of 0.3mm, an inner diameter of 0.05mm, a micropore size of 10-15nm, and a porosity of 70-80%.

[0027] Example 3

[0028] The following components and weight percentages are used: 20% polyethersulfone, 5% PVP (K90+K30), and 75% N-methyl-2-pyrrolidone. Part of the solvent and solids are initially mixed in a screw extruder. The raw materials are then added to a container, heated to 65°C, stirred and dissolved to form a solution. The solution is filtered and vacuum degassed for 5 hours. The spinning solution is then loaded into a barrel equipped with a heating and heat preservation function and maintained at 65°C. Methyl-2-pyrrolidone and water are mixed to form a spinning coagulation bath, with a weight concentration of 3% methyl-2-pyrrolidone. The core liquid formulation consists of 3% polydopamine, 50% dimethylacetamide, and the remainder purified water. The hollow fiber membrane is extruded through a spinneret for spinning and solidified by a dry-wet spinning process. The parameters are: an air layer height of 50 cm, a coagulation bath of a 3% by weight methyl-2-pyrrolidone aqueous solution at 50°C; stretching is performed in two stages, with a water bath as the stretching medium, the water bath temperature being 80°C, and the stretching ratio being 3 times; then the solvent and porogen are removed in 85°C water, the membrane is dried with nitrogen blown, and sterilized to obtain a polyethersulfone hollow fiber blend membrane with polydopamine attached to its inner surface. The hollow fiber membrane has an outer diameter of 0.3 mm, an inner diameter of 0.05 mm, a micropore diameter of 10-15 nm, and a porosity of 70-80%.

[0029] The above technical solutions only reflect the preferred technical solutions of the technical solutions of the present invention. Any changes that may be made to certain parts thereof by those skilled in the art all reflect the principles of the present invention and fall within the scope of protection of the present invention.

Claims

1. A polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface, characterized in that: Its raw material components include: 10-20wt% of polyethersulfone, 1-3wt% of polydopamine, 5-10wt% of porogen, and 60-85wt% of organic solvent; the outer diameter of the hollow fiber membrane is 0.1-50mm, the inner diameter is 0.1-50mm, the micropore diameter is 0.01um-1mm, and the porosity is 50-95%.

2. The polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface according to claim 1, characterized in that: The preparation method of the polydopamine comprises the following steps: Dopamine is oxidized in aqueous solution and undergoes cross-linking reaction to form a polydopamine composite layer rich in catechol groups on the surface of the material. Among them, the catechol active groups can react secondary. Under alkaline conditions, these groups are easily oxidized into quinone structures, thereby undergoing Michael addition and Schiff base reactions with thiol (-SH) molecules; catechol groups are easily oxidized to generate dopamine quinone compounds with catechol structures; dopamine and dopamine quinone undergo an anti-disproportionation reaction to produce semiquinone free radicals, which are then coupled to form cross-linked bonds to form polydopamines with different molecular weights; the preferred molecular weight in this experiment is 50,000-80,000 Daltons.

3. The polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface according to claim 2, characterized in that: The viscosity average molecular weight of the polyethersulfone is 40,000 to 120,000; the molecular weight of the polydopamine is 50,000 to 80,000.

4. The polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface according to claim 1, characterized in that: The porogen water-soluble polymer is one of starch, carboxymethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl chitosan, gelatin, polyethylene glycol, polyvinyl alcohol, polyacrylamide, polyacrylic acid, polyethylene oxide, polyethylene imine, and polyvinyl pyrrolidone (PVP).

5. The polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface according to claim 1, characterized in that: The organic solvent is one of dimethyl sulfoxide, N-methyl-2-pyrrolidone, dimethylamide and dimethylacetamide.

6. A method for preparing a polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface, characterized in that: The following steps are involved: (1) polyethersulfone and a porogen are added to an organic solvent, heated and stirred to form a uniform polymer solution, which is filtered and degassed to form a spinning solution; an aqueous solution of polydopamine and the solvent forms a core solution, wherein the polydopamine is 1-3%, the organic solvent is 30-50%, and the remainder is purified water; (2) The organic solvent of polyethersulfone and porogen and water are mixed to form a spinning coagulation bath, wherein the weight concentration of the organic solvent is 0 to 20% and the temperature is 0° C. to 70° C.

7. The method for preparing a polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface according to claim 6, characterized in that: The spinning solution is prepared from the following raw materials by weight percentage: 70-80% solvent, 10-20% membrane material, 2-4% PVP, and 0-3% purified water; wherein the solvent is dimethylacetamide (DMAC) and the membrane material is polyethersulfone (PES); the PVP is 80% PVP, K90 or 20% PVP, K30, thereby forming membrane micropores of appropriate size; wherein 80% PVP, K90 can produce large micropores to remove medium and large molecular toxins; 20% PVP, K30 can produce small micropores to remove water and small molecular toxins, maintain the uniformity of the micropore size, and at the same time maintain a certain pressure difference between the inside and outside of the membrane to avoid blood pressure fluctuations during dialysis.

8. The method for preparing a polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface according to claim 7, characterized in that: The preparation method of the spinning solution comprises the following steps: (1) PVP, membrane material, and 25-30% solvent are mixed and extruded in a screw extruder, mixed evenly, and a preliminary high-viscosity spinning solution is formed; after the extrusion is qualified, the solution is put into a stirring kettle, 50% solvent and 0-3% purified water are added; the solution is heated to 60-85°C and dissolved for 6-8 hours, and degassed at a negative pressure of 0.3-0.5 bar for 2-3 hours until the spinning solution is clear and transparent; (2) The spinning solution obtained in step (1) is extruded through a spinneret for spinning hollow fiber membranes, and solidified into a polyethersulfone hollow fiber membrane by wet spinning or dry-wet spinning, and polydopamine is attached to the inner surface of the membrane, with an air layer height of 20-50 cm; (3) The solidified polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface of the membrane is stretched 1 to 3 times in a water bath at a temperature of 50°C to 99°C; the residual solvent, part of the porogen, and part of the polydopamine are washed away in a water bath at 70°C to 99°C; and the membrane is dried at 80°C to 180°C to obtain the polyethersulfone hollow fiber blend membrane with polydopamine attached to the inner surface.