A pmp polymer breathable film and a method for preparing the same

Abstract

The application belongs to a PMP polymer breathable film and a preparation method thereof, and specifically comprises the following steps: step one, PES particle activation; step two, GO dispersion liquid and polymer solution are configured; step three, the activated PES particles are modified by being mixed with the GO dispersion liquid and the polymer solution in sequence; step four, a spinning solution is prepared; step five, a film is spun; step six, ultraviolet lithography; step seven, potential adjusting agent and post-irradiation sterilization; the application is significantly superior to the prior art in terms of breathability, mechanical strength, biocompatibility and structure controllability through material compounding, gradient pore-forming agent design, biomimetic modification and multi-process synergy (plasma treatment + ultraviolet crosslinking + lithography microchannel). The innovation directly aims at the defects of the traditional PMP film, and especially in the field of artificial lungs and hemodialysis, can realize efficient gas exchange, long-term stability and low biological risk.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a PMP polymer breathable membrane and its preparation method. Background Technology

[0002] Polymethylpentene (PMP) polymer breathable membranes have important applications in medical fields such as artificial lungs and hemodialysis membranes, but existing technologies have the following key drawbacks:

[0003] 1) Limitations in permeability and pore structure: Traditional PMP membranes have uneven pore distribution and low gas exchange efficiency due to the hydrophobicity of the material. Existing technologies mostly rely on simple pore-forming agents, resulting in insufficient pore size and connectivity, making it difficult to meet high permeability requirements. 2) Insufficient mechanical strength and durability: Existing PMP membranes are prone to cracking or deformation during long-term use due to mechanical stress (such as hydraulic shock in hemodialysis), mainly due to the lack of reinforcing fillers or cross-linking structures. 3) Biocompatibility issues: The oxygen permeability of existing polytetrafluoroethylene membranes contradicts blood compatibility, easily leading to thrombosis or inflammatory reactions on the membrane surface. 4) Complex and poorly controllable manufacturing processes: Existing technologies mostly rely on single modification methods (such as plasma treatment or chemical grafting), which are cumbersome and difficult to precisely control the multi-level structure of the membrane.

[0004] Therefore, providing a PMP polymer breathable membrane with high air permeability, stable mechanical properties, and high biocompatibility has become an urgent problem to be solved. Summary of the Invention

[0005] To address the above problems, this invention provides a PMP polymer breathable membrane and its preparation method, comprising the following steps:

[0006] Step 1: Mix polyethersulfone (PES) particles with a particle size of 100-200μm and a water content of <0.1% with anhydrous ethanol, ultrasonically clean at 40-50kHz for 20-30 minutes, remove and vacuum dry at 60-70℃ for 6-7 hours to remove surface residue.

[0007] Preferably, the mass ratio of the PES particles to anhydrous ethanol is 1:8.

[0008] Step 2: Place the PES particles into a radio frequency low-temperature plasma treatment device and introduce a mixed gas at a flow rate of 20-30 sccm. Turn on the device in pulse mode with a duty cycle of 45-55% and a frequency of 1-2 kHz. Set the reaction chamber pressure to 30-40 Pa, the material temperature to 35-40 °C, and the treatment time to 5-10 min. After turning off the plasma, continue to introduce nitrogen gas until the temperature reaches room temperature to obtain activated PES particles.

[0009] Preferably, the mixed gas is argon and oxygen in a volume ratio of 4:1.

[0010] Preferably, the nitrogen flow rate is 10-20 sccm.

[0011] Step 3: Mix graphene oxide with a thickness of 0.8-1.2 nm and a sheet diameter of 1-5 μm with an ethanol solution, and sonicate at 0-2℃ and 40-50 kHz for 30-40 min to obtain a GO dispersion; mix sulfobetaine methacrylate (SBMA), acrylic acid (AA) and phosphate buffer, and purge the mixture with nitrogen gas for 30-40 min at a flow rate of 50-60 mL / min to obtain a polymer solution.

[0012] Preferably, the ratio of graphene oxide to ethanol solution is 0.1 mg:1 mL. Most preferably, the volume fraction of the ethanol solution is 50%-60%.

[0013] Preferably, the ultrasonic on / off time is 5s / 2s.

[0014] Preferably, the ratio of SBMA, AA, and phosphate buffer is 13.5 mg: 1.5 mg: 1 mL.

[0015] Preferably, the phosphate buffer solution comprises 7 mM sodium dihydrogen phosphate (NaH2PO4) and 3 mM disodium hydrogen phosphate (Na2HPO4) based on water.

[0016] Step 4, (4.1) Mix the activated PES particles with the GO dispersion, shake at 40-50℃ and 120-150rpm for 3-4h, take out the PES particles, wash the surface with deionized water, and dry at 60-70℃ for 2-3h.

[0017] (4.2) Mix the dried PES particles with the polymer solution at a concentration of 250-260 nm and 15 mW / cm. 2 Irradiate the mixture with ultraviolet light at a distance of 8-10 cm from the surface for 20-30 min, remove the PES particles and wash the surface with anhydrous ethanol, then dry at 40-50℃ for 40-60 min.

[0018] (4.3) Repeat the process (4.1)→(4.2) 2-3 times with the PES particles obtained in (4.2) to obtain modified PES particles.

[0019] Preferably, the ratio of the activated PES particles, GO dispersion, and polymer solution is 5g:50mL:75mL.

[0020] Step 5: Mix polymethylpentene (PMP) and solvent, stir at 160-165℃ and 300-500rpm for 1-1.5h, then cool to 70-80℃ at 10℃ / min, add 30% of the total mass of polyacrylonitrile (PAN), plasticizer and porogen, stir at 600-800rpm for 40-60min, then cool to 50-60℃ at 5℃ / min, add 30% of the total mass of porogen and dispersant, stir at 1000-1200rpm for 1-1.5h, then cool to 30-40℃ at 5℃ / min, add 40% of the total mass of modified PES particles and porogen, stir at 800-1000rpm for 2-2.5h, then cool to 0-2℃, add biomimetic phospholipids, sonicate at 40-50kHz for 30-40min, degas at -0.08mPa for 30-40min, and obtain the spinning solution.

[0021] Preferably, the mass ratio of the total mass of the modified PES particles, PMP, PAN, plasticizer, dispersant, biomimetic phospholipid, pore-forming agent, and solvent is 12:9:8:3:1:1:5:80.

[0022] Preferably, the plasticizer is polyethylene glycol 400.

[0023] Preferably, the dispersant is a 30% sodium citrate solution.

[0024] Preferably, the pore-forming agent is polyethylene glycol 6000 and NaCl in a mass ratio of 4:1.

[0025] Preferably, the solvent is N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), and decahydronaphthalene in a mass ratio of 5:2:3.

[0026] Step 6: Inject the spinning solution into a multi-needle electrospinning machine with 21G stainless steel needles, an array spacing of 5cm, a spinning solution delivery rate of 1.0-1.2mL / h, an initial voltage of 18kV, increasing to 22kV at a rate of 2kV / h, an initial receiving distance of 15cm, increasing to 20cm at a rate of 0.5cm / h, and an initial spinning solution temperature of 70-80℃, increasing to 90-100℃ at a rate of 5℃ / h. The nascent membrane spun is dried at 50-55℃ and -0.09mPa for 2-2.5h, then mixed with an ethanol-water solution and shaken at 200-300rpm for 30-40min to obtain the finished membrane.

[0027] Preferably, the mass ratio of the primary membrane to the ethanol-water solution is 1:10, and the volume ratio of the ethanol to the water is 7:3.

[0028] Step 7: Mix the finished film with the deposition agent, sonicate at 50-60℃ for 10-20 minutes, then cure at 50-60℃ for 0.5-1 hour and at 70-80℃ for 1-1.5 hours.

[0029] Preferably, the mass ratio of the finished film to the deposition agent is 1:0.05.

[0030] Preferably, the deposition agent comprises fluorosilane (FAS-17), biomimetic phospholipid, coupling agent, anhydrous ethanol, and chloroform in a mass ratio of 2:1:0.1:70:30. Most preferably, the coupling agent is KH-570.

[0031] Step 8: Apply SU-83050 photoresist onto the film at a spin coating speed of 2000-2500 rpm, a thickness of 100-120 μm, and a PDMS microchannel template with a width of 50 μm and a depth of 100 μm, an aspect ratio of 2:1. Hold at -0.05 MPa for 5-10 minutes for adsorption and bonding, at a wavelength of 365 nm and an energy density of 200 mJ / cm². 2 Exposure time 45-50s, soak in PGMEA developer for 5-10min, then dry at 150-160℃ in a nitrogen atmosphere for 30-40min.

[0032] Preferably, the mass ratio of the membrane to the PGMEA developer is 1:1.

[0033] Step 9: Mix the membrane treated in Step 8 with the potential regulator and oscillate at 25-30℃ and 120-150rpm for 2-2.5h. After removing the membrane, irradiate it with γ at a dose of 25-35kGy under a nitrogen atmosphere. After irradiation, vacuum anneal at 60-70℃ for 2-2.5h to obtain the PMP polymer breathable membrane.

[0034] Preferably, the ratio of the membrane to the potential regulator is 10 g: 1 L. Most preferably, the potential regulator is a 0.2% sodium alginate solution.

[0035] The present invention has the following advantages:

[0036] (1) This invention enhances the hydrophilicity of the membrane surface by using GO dispersion and combines it with polyethylene glycol 6000 / NaCl gradient pore maker (added in stages) to form multi-level interconnected channels, which significantly improves the air permeability. Introducing biomimetic phospholipids into the spinning solution reduces channel blockage and further optimizes the gas diffusion path, thus solving the problems of uneven pore distribution and insufficient air permeability of traditional membranes.

[0037] (2) This invention activates PES particles with radio frequency plasma and then repeatedly composites them with GO / polymer solution to form a cross-linked network structure, which significantly improves tensile strength. Ultraviolet irradiation promotes the chemical bonding between SBMA-AA copolymer and PES particles, enhances interfacial bonding, and overcomes the problems of low mechanical strength and easy deformation of traditional PMP membranes.

[0038] (3) In this invention, biomimetic phospholipids and sodium alginate are introduced into the spinning solution and depositing agent to simulate the cell membrane structure and significantly reduce platelet adhesion. The NMP-DMAc-decahydronaphthalene composite solvent system is used in combination with vacuum degassing to ensure complete solvent evaporation, avoid biotoxicity, and eliminate the risk of solvent residue and biorejection in traditional processes.

[0039] (4) This invention combines electrospinning and photolithography to significantly improve gas / liquid exchange efficiency. By gradient pressure, dynamic receiving distance and temperature control, fiber diameter uniformity is achieved, solving the problems of poor structural controllability and easy blockage of microchannels in traditional processes. Detailed Implementation

[0040] The technical solutions in the embodiments of the invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] Step 1: PES particles with a particle size of 150μm and a water content of 0.05% are mixed with anhydrous ethanol at a mass ratio of 1:8, ultrasonically cleaned at 50kHz for 25min, and then vacuum dried at 65℃ for 6h to remove residual liquid on the surface.

[0043] Step two: Place the PES particles into a radio frequency low-temperature plasma treatment device and introduce a mixed gas at a flow rate of 25 sccm. The device is set to pulse mode with a duty cycle of 50%, a frequency of 2 kHz, a reaction chamber pressure of 35 Pa, a material temperature of 40°C, and a treatment time of 10 minutes. After the plasma is turned off, nitrogen is continuously introduced until the temperature reaches room temperature, resulting in activated PES particles. The mixed gas is argon and oxygen in a volume ratio of 4:1. The nitrogen flow rate is 15 sccm.

[0044] Step 3: Graphene oxide with a thickness of 1 nm and a sheet diameter of 1.2 μm was mixed with an ethanol solution at a ratio of 0.1 mg:1 mL, and sonicated at 1 °C and 50 kHz for 35 min, with the sonication on / off cycle lasting 5 s / 2 s, to obtain a GO dispersion. SBMA, AA, and phosphate buffer were mixed at a ratio of 13.5 mg:1.5 mg:1 mL, and nitrogen gas was bubbled through the mixture for 30 min at a flow rate of 50 mL / min to obtain a polymer solution. The ethanol solution had a volume fraction of 50%. The phosphate buffer, based on water, included 7 mM NaH2PO4 and 3 mM Na2HPO4.

[0045] Step 4, (4.1) Mix the activated PES particles with the GO dispersion, shake at 45°C and 120 rpm for 3 h, take out the PES particles, wash the surface with deionized water, and dry at 65°C for 2.5 h.

[0046] (4.2) The dried PES particles were mixed with the polymer solution at 254 nm and 15 mW / cm. 2 Irradiate the mixture with ultraviolet light at a distance of 10 cm from the surface for 30 min, remove the PES particles and wash the surface with anhydrous ethanol, then dry at 45℃ for 50 min.

[0047] (4.3) The PES particles obtained in (4.2) are repeated three times according to the method of (4.1)→(4.2) to obtain modified PES particles. The ratio of activated PES particles, GO dispersion and polymer solution is 5g:50mL:75mL.

[0048] Step 5: Mix PMP and solvent, stir at 163℃ and 400rpm for 1.5h, then cool to 80℃ at 10℃ / min, add PAN, polyethylene glycol 400 and 30% of the total mass of porogen, stir at 700rpm for 50min, then cool to 60℃ at 5℃ / min, add 30% of the total mass of porogen and 30% of the mass of sodium citrate solution, stir at 1200rpm for 1h, then cool to 40℃ at 5℃ / min, add modified PES particles and 40% of the total mass of porogen, stir at 1000rpm for 2h, then cool to 1℃, add biomimetic phospholipids, sonicate at 50kHz for 40min, degas at -0.08mPa for 30min, and obtain the spinning solution. The mass ratio of the modified PES particles, PMP, PAN, polyethylene glycol 400, sodium citrate solution, biomimetic phospholipids, total mass of porogen and solvent is 12:9:8:3:1:1:5:80. The pore-forming agent is polyethylene glycol 6000 and NaCl in a mass ratio of 4:1. The solvent is NMP, DMAc, and decahydronaphthalene in a mass ratio of 5:2:3.

[0049] Step Six: The spinning solution is injected into a multi-needle electrospinning machine with 21G stainless steel needles, an array spacing of 5cm, a spinning solution delivery rate of 1.0mL / h, an initial voltage of 18kV, increased to 22kV at a rate of 2kV / h, an initial receiving distance of 15cm, increased to 20cm at a rate of 0.5cm / h, and an initial spinning solution temperature of 80℃, increased to 90℃ at a rate of 5℃ / h. The spun nascent membrane is dried at 50℃ and -0.09mPa for 2h, then mixed with an ethanol-water solution and shaken at 300rpm for 30min to obtain the finished membrane. The mass ratio of the nascent membrane to the ethanol-water solution is 1:10, and the volume ratio of ethanol to water is 7:3.

[0050] Step 7: Mix the finished membrane with the deposition agent, sonicate at 55℃ for 15 minutes, then cure at 60℃ for 0.5 hours and at 80℃ for 1 hour. The mass ratio of the finished membrane to the deposition agent is 1:0.05. The deposition agent includes FAS-17, biomimetic phospholipids, KH-570, anhydrous ethanol, and chloroform, with a mass ratio of 2:1:0.1:70:30.

[0051] Step 8: Apply SU-83050 photoresist onto the film at a spin coating speed of 2200 rpm to a thickness of 110 μm. Use a PDMS microchannel template with a width of 50 μm and a depth of 100 μm, with an aspect ratio of 2:1. Hold at -0.05 MPa for 10 minutes for adsorption and bonding. Use a wavelength of 365 nm and an energy density of 200 mJ / cm². 2 The exposure time was 50 seconds, followed by immersion in PGMEA developer for 10 minutes, and then drying at 150°C under a nitrogen atmosphere for 30 minutes. The mass ratio of the film to the PGMEA developer was 1:1.

[0052] Step nine: The membrane treated in step eight is mixed with a 0.2% sodium alginate solution and shaken at 30°C and 150 rpm for 2 hours. After removal, the membrane is subjected to γ-irradiation at a dose of 30 kGy under a nitrogen atmosphere, followed by vacuum annealing at 65°C for 2 hours to obtain a PMP polymer breathable membrane. The ratio of the membrane to the 0.2% sodium alginate solution is 10 g: 1 L.

[0053] Experimental Example 1

[0054] Test equipment and conditions:

[0055] Gas permeability tester (LabthinkVAC-V2); Test gas: pure oxygen (purity ≥99.99%); Temperature: 25±0.5℃; Effective membrane area: 10cm² 2 Pressure difference: 1 bar (downstream is a vacuum chamber).

[0056] Experimental steps:

[0057] 1. Sample preparation: The PMP membrane prepared in Example 1 (experimental group) and the traditional medical-grade polytetrafluoroethylene membrane (control group) purchased from Dongguan Shengli New Materials Co., Ltd. were respectively made into circular samples with a diameter of 5cm and uniform thickness (±0.02mm); the samples were equilibrated for 24h at 25℃ and 50% humidity.

[0058] 2. Test procedure: Clamp the membrane sample in the test chamber, seal it, and evacuate it to ≤10Pa; introduce pure oxygen upstream and maintain the pressure at 1 bar, and record the downstream oxygen permeation rate (mL / min); repeat the test 5 times for each group of samples and take the average value;

[0059] 3. Data Processing: Oxygen Transport Efficiency (OTE) calculation formula: OTE = Permeation Rate / Membrane Area (mL / min·cm²) 2 )

[0060] The OTE values ​​of the membrane of this invention and the conventional membrane were compared, and the percentage improvement was calculated. The results are shown in Table 1.

[0061] Experimental Example 2

[0062] Experimental materials and conditions: Fresh platelet-rich plasma (PRP, platelet concentration ≥ 2 × 10⁻⁶) 5 / μL); phosphate buffer (PBS, pH 7.4); 2.5% glutaraldehyde solution (fixative); scanning electron microscope (SEM, Hitachi SU8010); platelet adhesion rate quantification kit (e.g., lactate dehydrogenase method, LDH detection);

[0063] Experimental steps: 1. Sample pretreatment: Prepare the membrane sample (1×1cm). 2 Soak in PBS for 24 hours to remove residual solvent; sterilize with UV for 30 minutes and place in a 24-well plate.

[0064] 2. Platelet contact assay: Add 1 mL PRP to each well, incubate at 37°C for 2 h, gently rinse 3 times with PBS to remove unadhered platelets, fix with 2.5% glutaraldehyde for 30 min, dehydrate in a gradient (50%–100% ethanol), and dry at the critical point.

[0065] 3. Adhesion rate detection:

[0066] LDH method: Immerse the platelet-adhered membrane in 1% Triton X-100 lysis buffer, centrifuge, collect the supernatant, and detect LDH activity according to the kit instructions to calculate the adhesion rate.

[0067] Adhesion rate = Sample LDH activity / Total LDH activity × 100%.

[0068] Each group of samples was repeated 3 times, and the average value was taken. The results are shown in Table 1.

[0069] Experimental Example 3

[0070] Test conditions: simulated body fluid (Hank's balanced salt solution, pH 7.4, 37℃); mechanical stress simulation: cyclic pressure (0~100mmHg, frequency 1Hz); test cycle: 72 hours.

[0071] Experimental steps: 1. Initial performance test: Record the initial oxygen transport efficiency (OTE) and tensile strength of the membrane (universal testing machine, ASTM D638 standard).

[0072] 2. Continuous simulation: Place the membrane sample in simulated body fluid and apply circulatory pressure (simulating the hemodialysis environment). Remove the sample every 24 hours and test it according to the following steps:

[0073] OTE test: Same as in Experiment 1, oxygen transport efficiency determination;

[0074] Tensile strength test: Tensile rate 10 mm / min, record the breaking strength;

[0075] SEM observation: Check whether the pore structure on the membrane surface is blocked or deformed;

[0076] 3. Performance degradation calculation: Degradation rate formula:

[0077] Attenuation value = (initial value - 72-hour value) / initial value × 100%

[0078] Each group of samples was repeated 3 times, and the average value was taken. The results are shown in Table 1.

[0079] Table 1

[0080]

[0081]

[0082] As shown in Table 1, this invention enhances pore connectivity through gradient pore-forming agents and GO, resulting in a 40% increase in OTE compared to traditional PTFE membranes. This invention also significantly reduces platelet adhesion rate to 8.5% through biomimetic phospholipid modification, approaching the clinical safety threshold (<10%). After 72 hours of continuous operation, the PMP membrane prepared by this invention exhibits a decrease in both OTE and mechanical strength of <10%, significantly superior to traditional PTFE membranes, meeting the requirements for long-term medical use.

[0083] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a PMP polymer breathable membrane, characterized in that, Includes the following steps: Step 1: PES particles are treated with radio frequency plasma to obtain activated PES particles. Step 2: Graphene oxide is mixed with ethanol solution to obtain GO dispersion, SBMA, AA acrylic acid and buffer are mixed, and nitrogen gas is passed into the mixture to obtain polymer solution; Step 3, (3.1) Mix and shake the activated PES particles with the GO dispersion, and then remove the PES particles to clean their surface; (3.2) Mix the dried PES particles with the polymer solution, irradiate with ultraviolet light, remove the PES particles and clean the surface to obtain modified PES particles. Step 4: Mix PMP and solvent, stir at 160-165℃, then cool to 70-80℃, add 30% of the total mass of PAN, plasticizer and porogen, stir, then cool to 50-60℃, add 30% of the total mass of porogen and dispersant, stir, then cool to 30-40℃, add 40% of the total mass of modified PES particles and porogen, stir, then cool to 0-2℃, add biomimetic phospholipid, ultrasonically disperse, and vacuum degas to obtain spinning solution; Step 5: Inject the spinning solution into a multi-needle electrospinning machine with a voltage of 18-22kV, a receiving distance of 15cm-20cm, and a spinning solution temperature of 70-100℃ to obtain a nascent film. Dry the film and mix it with an ethanol-water solution to obtain a finished film. Then mix the finished film with a deposition agent, ultrasonically treat it, and solidify it. Step six: Apply photoresist to the film treated in step five, adhere the microchannel template, expose to ultraviolet light, immerse in developer, and dry. Step 7: The membrane treated in step 6 is mixed with a potential regulator and oscillated, then irradiated with γ to obtain a PMP polymer breathable membrane.

2. The method for preparing a PMP polymer breathable membrane according to claim 1, characterized in that, In step two, the ratio of graphene oxide to ethanol solution is 0.1 mg: 1 mL, and the ratio of SBMA, AA acrylate, and buffer solution is 13.5 mg: 1.5 mg: 1 mL.

3. The method for preparing a PMP polymer breathable membrane according to claim 1, characterized in that, The volume fraction of the ethanol solution in step two is 50%-60%, and the buffer solution is based on water and includes 7mM NaH2PO4 and 3mM Na2HPO4.

4. The method for preparing a PMP polymer breathable membrane according to claim 1, characterized in that, In step three, the ratio of activated PES particles, GO dispersion, and polymer solution is 5g:50mL:75mL.

5. The method for preparing a PMP polymer breathable membrane according to claim 1, characterized in that, Step three also includes (3.3), which involves repeating the PES particles obtained in (3.2) 2-3 times according to the method of (3.1)→(3.2) to obtain modified PES particles.

6. The method for preparing a PMP polymer breathable membrane according to claim 1, characterized in that, The mass ratio of the total mass of the modified PES particles, PMP, PAN, plasticizer, dispersant, biomimetic phospholipid, pore-forming agent, and solvent in step four is 12:9:8:3:1:1:5:

80.

7. The method for preparing a PMP polymer breathable membrane according to claim 1, characterized in that, The plasticizer mentioned in step four is polyethylene glycol 400, the dispersant is a 30% sodium citrate solution, the pore-forming agent is polyethylene glycol 6000 and NaCl in a mass ratio of 4:1, and the solvent is NMP, DMAc and decahydronaphthalene in a mass ratio of 5:2:

3.

8. The method for preparing a PMP polymer breathable membrane according to claim 1, characterized in that, The depositing agent comprises FAS-17, biomimetic phospholipids, coupling agents, anhydrous ethanol, and chloroform in a mass ratio of 2:1:0.1:70:

30.

9. The method for preparing a PMP polymer breathable membrane according to claim 1, characterized in that, The potential regulator is a 0.2% sodium alginate solution.

10. The PMP polymer breathable membrane prepared by the method according to any one of claims 1-9.

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