Medical polyethersulfone as well as preparation method and application thereof

Abstract

The invention belongs to the field of high polymer material synthesis, and relates to medical polyethersulfone as well as a preparation method and application thereof. The prepared medical polyethersulfone has excellent gamma ray resistance stability, the weight-average molecular weight retention rate is greater than 85% after gamma ray irradiation sterilization, the key problem that the performance of the polyethersulfone is obviously reduced after irradiation sterilization is solved, and the medical polyethersulfone has important significance for improving the medical value of the polyethersulfone.

Description

Technical Field

[0001] The present invention belongs to the field of polymer material synthesis, and specifically, relates to a medical polyethersulfone and its preparation method and application. Background Art

[0002] Polyethersulfone is a thermoplastic polymer material with excellent thermal stability, water vapor resistance, mechanical strength, biocompatibility, etc., and is widely used in the fields of electronics and electrical appliances, transportation, kitchenware, medical devices, etc., especially having irreplaceable advantages in the field of hemodialysis membranes.

[0003] In recent years, hemodialysis has been the main means for treating kidney diseases, so the demand for high-end polyethersulfone dialysis materials has been continuously increasing. However, in the actual use process, when conventional polyethersulfone is used as a medical dialysis material, problems such as reduced dialysis effect and decreased mechanical properties, which cannot meet the dialysis requirements, will occur. In severe cases, this problem will endanger the health of patients. Therefore, developing a medical polyethersulfone with stable performance and suitable for the medical device field is an important topic.

[0004] In addition, the assembled hemodialyzer needs to be sterilized before use. Generally, the sterilization methods used are gamma ray (γ-ray) irradiation, electron beam irradiation, high-temperature steam sterilization or ethylene oxide method. Due to the advantages of simple operation and no residual toxicity of γ-ray, it is frequently used. Invention Patent CN 3107983B2 discloses a method for γ-ray irradiation sterilization of a hemodialyzer, and uses an aqueous solution of propylene glycol or polypropylene glycol, phosphate buffer solution, etc. to moisten the dialysis membrane before irradiation to weaken the deterioration of the membrane, but the author did not characterize the influence of irradiation on the structure and molecular weight of the dialysis material. Invention Patent JP4288601B2 discloses a method for irradiating a polysulfone-based hemodialysis membrane with γ-ray irradiation sterilization. After irradiation at 40 kGy / h, the breaking strength of the hollow fiber membrane is reduced to about 80% of that before irradiation, indicating that the polysulfone material has deteriorated after γ-ray irradiation, but the author did not further study the deterioration. At present, there are few reports on the research of the influence of irradiation on the structure of dialysis materials. Summary of the Invention

[0005] The inventors of the present application unexpectedly found through research that after polyethersulfone polymer materials are irradiated with gamma rays (γ-rays), because γ-rays are high-energy rays, they will stimulate the polymer materials to generate a large number of free radicals, causing irreversible damage to the materials, such as chain scission, crosslinking, embrittlement, etc. of the polymer chains, thus resulting in reduced dialysis effect and decreased mechanical properties, which cannot meet the dialysis requirements. On this basis, to solve the problem that the performance of polyethersulfone drops significantly after γ-ray irradiation, a medical polyethersulfone product with good radiation sterilization resistance and suitable for the medical device field is developed.

[0006] Another object of the present invention is to provide a method for preparing such a medical polyethersulfone resistant to γ-ray irradiation.

[0007] A further object of the present invention is to provide the application of such a medical polyethersulfone.

[0008] To achieve the above invention objects, the present invention adopts the following technical solutions:

[0009] A medical polyethersulfone, the structure of which is shown in Formula 1:

[0010]

[0011] The medical polyethersulfone satisfies the following formula after being sterilized by γ-ray irradiation:

[0012] x = M2 / M1 > 85%; preferably: x = M2 / M1 > 98%;

[0013] Wherein, M1 is the weight-average molecular weight measured by GPC of the polyethersulfone before being sterilized by γ-ray irradiation, and M2 is the weight-average molecular weight measured by GPC of the polyethersulfone after being sterilized by γ-ray irradiation.

[0014] In some specific embodiments, the total amount of residual monomers in the medical polyethersulfone is < 20 ppm, the residual solvent is < 20 ppm, and the metal ion content is < 50 ppm.

[0015] In some specific embodiments, the γ-ray irradiation sterilization is carried out under normal temperature, normal pressure and static conditions, the γ-ray irradiation intensity is 10 - 150 kGy / h, and the irradiation treatment time is 5 min to 48 h.

[0016] In some specific embodiments, the weight-average molecular weight of the polyethersulfone measured by GPC before being sterilized by γ-ray irradiation is between 40,000 and 200,000 g / mol, preferably 40,000 - 120,000 g / mol.

[0017] On the other hand, the preparation method of the aforementioned medical polyethersulfone is characterized by comprising the following steps:

[0018] Dissolve monomer one and monomer two in the first organic solvent, then add the salt-forming agent and the second organic solvent to the reaction kettle in portions or continuously under stirring, carry out the salt-forming reaction for 2 - 6 h, the salt-forming reaction temperature is 140 - 210 °C, preferably adopt the way of gradient temperature rise, after the salt-forming is completed, raise the temperature to completely evaporate the second solvent in the reaction kettle, then react at 160 - 230 °C for 2 - 48 h, then add the first organic solvent for dilution, add the end-capping agent, and then filter press, crush, wash and dry the reaction solution to obtain the medical polyethersulfone.

[0019] In some specific embodiments, the first monomer is any one of bisphenol S, bisphenol A, and 4,4'-dihydroxybiphenyl; and / or

[0020] the second monomer is dichlorodiphenyl sulfone; and / or

[0021] the salt-forming agent is one or more of sodium hydroxide, potassium hydroxide, cesium hydroxide, potassium carbonate, sodium carbonate, barium carbonate, cesium carbonate, potassium bicarbonate, and sodium bicarbonate; and / or

[0022] the first organic solvent is one or more of N-methylpyrrolidone, dimethyl sulfone, diphenyl sulfone, sulfolane, N,N-dimethylformamide, and N,N-dimethylacetamide; and / or

[0023] the second organic solvent is one or more of toluene, xylene, o-xylene, mesitylene, chlorobenzene, and dichlorobenzene; and / or

[0024] the capping agent is one or more of chloromethane and 4-chlorophenyl phenyl sulfone.

[0025] In some specific embodiments,

[0026] the molar ratio of the first monomer to the second monomer is 1.0 - 1.05:1; and / or

[0027] the addition amount of the salt-forming agent is 1.05 - 1.5 times the molar amount of the first monomer; and / or

[0028] the addition amount of the first organic solvent is 25 - 60 times the molar amount of the first monomer; and / or

[0029] the addition amount of the second organic solvent is 10 - 50% of the mass of the first solvent; and / or

[0030] the addition amount of the capping agent is 0.05 - 0.5 times the molar amount of the first monomer; and / or;

[0031] Preferably, the temperature of the salt-forming reaction is 180 - 200 °C, and the reaction time is 3 - 5 h.

[0032] In some specific embodiments, the capping agent is added or introduced in multiple equal or unequal portions, and the capping temperature is between 130 °C and 190 °C;

[0033] Preferably, when the capping agent is chloromethane, the pipe for introducing chloromethane is perforated every 0.2 - 20 cm, and the pore diameter is 0.1 - 1 cm.

[0034] In some specific embodiments, the washing is performed by boiling in water and / or washing with an aqueous solution of an organic solvent;

[0035] Preferably, the organic solvent is selected from at least one of methanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and sulfolane. The mass content of water in the aqueous solution of the organic solvent is preferably between 10% and 90%.

[0036] In a preferred embodiment, monomer one and monomer two are dissolved in a first organic solvent, and then a salt-forming agent and a second organic solvent are added to the reaction kettle in portions or continuously with stirring. The salt-forming reaction is carried out at 140-210°C for 2-6 h. After the salt-forming reaction is completed, the temperature is raised to completely evaporate the second solvent in the reaction kettle. Subsequently, the reaction is carried out at 160-230°C for 2-48 h. Then, a first organic solvent is added for dilution, and a capping agent is added. The capping agent is added or introduced in multiple equal or unequal portions, and the capping temperature is between 130°C and 190°C. Subsequently, the reaction solution is pressure-filtered, crushed, washed, and dried to obtain the medical polyethersulfone.

[0037] On the other hand, the application of the aforementioned medical polyethersulfone or the medical polyethersulfone prepared by the aforementioned preparation method in the field of medical devices, especially in the field of hemodialysis membranes.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention creatively develops a medical polyethersulfone product suitable for the field of medical devices. After being sterilized by gamma-ray irradiation, the weight-average molecular weight retention rate of the polyethersulfone measured by GPC is greater than 85%, which solves the key problem that the performance of the polyethersulfone significantly decreases after irradiation disinfection, and is of great significance for improving the medical value of the polyethersulfone.

[0040] The preparation method of the present invention enhances the structural stability of the polyethersulfone by increasing the chloromethane capping rate, and further reduces the content of various impurities such as residual monomers, residual solvents, and metal ions in the polymer, reduces the generation of free radicals during the irradiation process, and avoids the significant reduction of the performance of the prepared polyethersulfone after gamma-ray irradiation sterilization. Detailed Embodiments

[0041] Other features and advantages of the present invention will be described in conjunction with the detailed embodiments section. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein.

[0042] In one aspect of the present invention, a medical polyethersulfone has a structure as shown in Formula 1:

[0043]

[0044] The medical polyethersulfone satisfies the following formula after being sterilized by gamma-ray irradiation:

[0045] x = M2 / M1 > 85%, such as 86%, 87%, 88%, 89.5%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.6%, 99.8%, 99.9%, etc.; preferably: x = M2 / M1 > 98%;

[0046] Wherein, M1 is the weight - average molecular weight of polyethersulfone measured by GPC before γ - ray irradiation sterilization, and M2 is the weight - average molecular weight of polyethersulfone measured by GPC after γ - ray irradiation sterilization. The test conditions for measuring the weight - average molecular weight of polyethersulfone by GPC in the present invention are as follows. Those skilled in the art can understand that when measuring the molecular weight by GPC, different mobile phases have an impact on the molecular weight size, but show the same law for the ratio of molecular weights and have little impact.

[0047] In a preferred embodiment, the total amount of residual monomers in the medical polyethersulfone < 20 ppm, such as 19 ppm, 18 ppm, 17 ppm, 15 ppm, 14 ppm, 13 ppm, 12 ppm, 11 ppm, 10 ppm, 9 ppm, 8 ppm, 7 ppm, 6 ppm, 5 ppm, 4 ppm, 3 ppm, 2 ppm, 1 ppm, etc., the residual solvent < 20 ppm, such as 19 ppm, 18 ppm, 17 ppm, 15 ppm, 14 ppm, 13 ppm, 12 ppm, 11 ppm, 10 ppm, 9 ppm, 8 ppm, 7 ppm, 6 ppm, 5 ppm, 4 ppm, 3 ppm, 2 ppm, 1 ppm, etc., and the metal ion content < 50 ppm, such as 50 ppm, 40 ppm, 30 ppm, 20 ppm, 10 ppm, 8 ppm, 7 ppm, 6 ppm, 5 ppm, 3 ppm, 2 ppm, 1 ppm, etc.

[0048] In some specific embodiments, the γ - ray irradiation sterilization is carried out under normal temperature, normal pressure and static conditions. The γ - ray irradiation intensity is 10 - 150 kGy / h, such as 15 kGy / h, 20 kGy / h, 30 kGy / h, 45 kGy / h, 50 kGy / h, 60 kGy / h, 70 kGy / h, 80 kGy / h, 90 kGy / h, 100 kGy / h, 110 kGy / h, 120 kGy / h, 130 kGy / h, 140 kGy / h, etc., and the irradiation treatment time is 5 min to 48 h, such as 40 min, 1 h, 5 h, 10 h, 15 h, 20 h, 30 h, 35 h, 40 h, etc.

[0049] In a preferred embodiment, the weight-average molecular weight of the polyethersulfone determined by GPC before being sterilized by γ-ray irradiation is between 40,000 and 200,000 g / mol, such as 50,000, 60,000, 80,000, 100,000, 110,000, 125,000, 140,000, 150,000, 160,000, 170,000, 180,000, 190,000 g / mol, etc., and preferably is between 40,000 and 120,000 g / mol.

[0050] Those skilled in the art can understand that after the polyethersulfone product with the aforementioned performance characteristics is sterilized by γ-ray irradiation, its performance basically remains unchanged, and there will be no problem of reduced dialysis effect. It can be fully applied to the medical device field, especially the hemodialysis membrane field, regardless of the preparation method used. Below, a preparation method of a medical polyethersulfone product with the above performance characteristics will be exemplarily given, but it does not mean that only this specific method can obtain the product with the above performance characteristics.

[0051] In a specific embodiment, the medical polyethersulfone is prepared by a method including the following steps:

[0052] Dissolve monomer one and monomer two in the first organic solvent, and then add the salt-forming agent and the second organic solvent to the reaction kettle in portions or continuously under stirring, heat to 140 - 210 °C for reflux reaction for 2 - 6 h, such as reflux at 145 °C, 150 °C, 160 °C, 165 °C, 170 °C, 175 °C, 180 °C, 185 °C, 190 °C, 195 °C, 200 °C, 210 °C for 3, 4, 5 h, etc., raise the temperature to completely distill out the second solvent in the reaction kettle, and then react at 160 - 230 °C for 2 - 48 h, such as react at 160 °C, 165 °C, 170 °C, 175 °C, 180 °C, 185 °C, 190 °C, 195 °C, 200 °C, 210 °C, 220 °C, 230 °C for 3, 4, 5, 10, 15, 20, 25, 30, 35, 40 h, then add the first organic solvent for dilution, add a certain amount of capping agent, and then filter press, crush, wash, and dry the reaction solution to obtain polyethersulfone;

[0053] More specifically, the monomer one is any one of bisphenol S, bisphenol A, and 4,4'-dihydroxybiphenyl, preferably bisphenol S; the monomer two is dichlorodiphenyl sulfone; the salt-forming agent is one or more of sodium hydroxide, potassium hydroxide, cesium hydroxide, potassium carbonate, sodium carbonate, barium carbonate, cesium carbonate, potassium bicarbonate, and sodium bicarbonate; the first organic solvent is one or more of dimethyl sulfone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, diphenyl sulfone, and sulfolane; the second organic solvent is one or more of toluene, xylene, o-xylene, chlorobenzene, and dichlorobenzene; the capping agent is chloromethane.

[0054] Among them, the molar ratio of the amounts of each raw material is monomer one: monomer two: salt-forming agent: first organic solvent: capping agent = 1: 1 to 1.05: 1.1 to 1.5: 25 to 60: 0.05 to 0.5. For example, 1: 1: 1.1: 25: 0.05, 1: 1.05: 1.5: 60: 0.5, 1: 1.01: 1.4: 40: 0.3, 1: 1.05: 1.1: 30: 0.1, 1: 1.02: 1.15: 30: 0.2, etc. The amount of the second organic solvent is 10% to 50% of the mass of the first organic solvent. For example, 20%, 30%, 40%, etc.

[0055] The present invention improves the chloroform capping rate to improve the γ-ray irradiation stability of the polyethersulfone product. The capping agent of the present invention is added in multiple equal portions or multiple unequal portions, such as 2 times, 3 times, 4 times, 5 times or more, preferably 3 times. Specifically, for example, the capping agent is added in three equal portions three times, or added in three unequal portions such as 1: 2: 3 or 1: 3: 5, etc. Preferably, a porous gas pipe is inserted below the liquid surface to introduce the capping agent, and at the same time, the capping temperature is controlled between 130 °C and 190 °C, such as 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, etc., to improve the chloroform capping rate, thereby improving the γ-ray irradiation stability of the polyethersulfone product, that is, after γ-ray irradiation, the performance of the polyethersulfone product hardly deteriorates and meets the requirements of hemodialysis.

[0056] The present invention also finds that by controlling the total amount of residual monomers in the polyethersulfone < 20 ppm, the residual solvent < 20 ppm, and the metal ion content < 100 ppm, the γ-ray irradiation stability of the polyethersulfone can be further enhanced. To reduce the content of impurities such as residual monomers, residual solvents, and metal ions, the present invention adopts the methods of boiling with water, washing with alcohol, or washing with an aqueous solution of an organic solvent. Among them, the range of the organic solvent includes but is not limited to any one of methanol, ethanol, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, and sulfolane. Preferably, the mass content of water in the aqueous solution of the organic solvent is between 10% and 90%, such as 20%, 35%, 40%, 50%, 55%, 60%, 70%, 80%, etc. Among them, the metal ion is mainly potassium ion because potassium is generated by the reaction of the salt-forming agent and has the highest content, while other metal ions are almost introduced by the environment or equipment and have a very low content and can be ignored.

[0057] The reaction conditions of the present invention are all carried out under a nitrogen atmosphere. The reaction vessel used is baked and dried to remove water, and evacuated and filled with nitrogen multiple times.

[0058] The method of the present invention is further explained and illustrated by more specific examples below, but it does not constitute any limitation.

[0059] Method for testing the molecular weight of polyethersulfone: Using DMF containing 20 mmol of lithium bromide as the mobile phase, PMMA as the standard sample, and connecting Agilent MIXD C, MIXD D, and MIXD E columns in series, with a flow rate of 1.0 mL / min.

[0060] The total amount of residual monomers in polyethersulfone is analyzed by liquid chromatography, the total amount of residual solvents is analyzed by gas chromatography, and the K ion content is analyzed by inductively coupled plasma emission spectrometer.

[0061] Example 1

[0062] A method for synthesizing and irradiating polyethersulfone for sterilization, the detailed steps are as follows: Add 2002 g of bisphenol S and 2320 g of dichlorodiphenyl sulfone to 6894 g of sulfolane in sequence for dissolution, add 1327 g of potassium carbonate, keep the system temperature at 180 °C, reflux with xylene for 2 h, then release a certain amount of xylene and raise the temperature to 200 °C and continue refluxing for 2 h. After no water is produced, raise the temperature to 220 °C to completely distill out the xylene in the reaction kettle, continue the reaction at 220 °C for 3.5 h, then add 4224 g of sulfolane for dilution. After the system cools down to 150 °C, introduce chloromethane until the pressure in the reaction kettle reaches 0.3 mPa for sealed capping. After 30 min, introduce chloromethane again to make the pressure in the reaction kettle reach 0.3 mPa and continue capping. Repeat introducing chloromethane 3 times, and then the capping ends. Subsequently, release the reaction solution, filter it under pressure, crush it, wash it, and dry it under vacuum to obtain polyethersulfone. The total amount of residual monomers in polyethersulfone is 10 ppm, the total amount of residual solvents is 8 ppm, and the K ion content is 16 ppm.

[0063] Molecular structure characterization: The weight-average molecular weight of polyethersulfone is 96650 g / mol, and the molecular weight distribution is 1.71. After being irradiated with gamma rays at an intensity of 75 kGy / h for 30 min, M2 / M1 = 99.0%. After being irradiated with gamma rays at an intensity of 100 kGy / h for 5 min, M2 / M1 = 98.2%.

[0064] Example 2

[0065] A method for preparing polyethersulfone, which is different from Example 1 in that: Using N-methylpyrrolidone as the solvent, the polymerization temperature is 200 °C, and the polymerization time is 3 h. The total amount of residual monomers in polyethersulfone is 10 ppm, the total amount of residual solvents is 14 ppm, and the K ion content is 15 ppm.

[0066] Molecular structure characterization: The weight-average molecular weight of polyethersulfone is 97210 g / mol, and the molecular weight distribution is 1.68. After being irradiated with gamma rays at an intensity of 75 kGy / h for 30 min, M2 / M1 = 98.8%.

[0067] Example 3

[0068] A preparation method of polyethersulfone, different from Example 1 in that: the capping temperature is 130 °C, and methyl chloride is introduced to make the pressure in the reaction kettle reach 0.5 mPa. The total amount of residual monomers in the polyethersulfone is 15 ppm, the total amount of residual solvents is 10 ppm, and the K ion content is 12 ppm.

[0069] Molecular structure characterization: The weight-average molecular weight of the polyethersulfone is 97040 g / mol, and the molecular weight distribution is 1.73. After being irradiated with gamma rays at a strength of 75 kGy / h for 30 min, M2 / M1 = 99.5%.

[0070] Example 4

[0071] A preparation method of polyethersulfone, different from Example 1 in that: the capping temperature is 170 °C, and methyl chloride is introduced to make the pressure in the reaction kettle reach 0.2 mPa. The total amount of residual monomers in the polyethersulfone is 18 ppm, the total amount of residual solvents is 15 ppm, and the K ion content is 20 ppm.

[0072] Molecular structure characterization: The weight-average molecular weight of the polyethersulfone is 96580 g / mol, and the molecular weight distribution is 1.78. After being irradiated with gamma rays at a strength of 75 kGy / h for 30 min, M2 / M1 = 98.4%.

[0073] Example 5

[0074] A preparation method of polyethersulfone, different from Example 1 in that: methyl chloride is introduced to make the pressure in the reaction kettle reach 0.1 mPa. The total amount of residual monomers in the polyethersulfone is 16 ppm, the total amount of residual solvents is 18 ppm, and the K ion content is 14 ppm.

[0075] Molecular structure characterization: The weight-average molecular weight of the polyethersulfone is 96020 g / mol, and the molecular weight distribution is 0.174. After being irradiated with gamma rays at a strength of 75 kGy / h for 30 min, M2 / M1 = 98.1%.

[0076] Example 6

[0077] A preparation method of polyethersulfone, different from Example 1 in that: the capping temperature is 140 °C, and methyl chloride is introduced for the first, second, and third times to make the pressure in the reaction kettle reach 0.1, 0.3, and 0.5 mPa respectively. The total amount of residual monomers in the polyethersulfone is 10 ppm, the total amount of residual solvents is 10 ppm, and the K ion content is 9 ppm.

[0078] Molecular structure characterization: The weight-average molecular weight of the polyethersulfone is 96820 g / mol, and the molecular weight distribution is 1.75. After being irradiated with gamma rays at a strength of 75 kGy / h for 30 min, M2 / M1 = 99.3%.

[0079] Comparative Example 1

[0080] A method for preparing polyethersulfone, which is different from Example 1 in that the end-capping temperature is 200° C. The total amount of residual monomers in the polyethersulfone is 50 ppm, the total amount of residual solvent is 40 ppm, and the K ion content is 35 ppm.

[0081] Molecular structure characterization: The weight average molecular weight of polyethersulfone is 96530 g / mol, and the molecular weight distribution is 1.92. After being irradiated with gamma rays at an intensity of 75 kGy / h for 30 minutes, M2 / M1=82.0%.

[0082] Comparative Example 2

[0083] A method for preparing polyethersulfone, which is different from Example 1 in that methyl chloride is introduced once to make the pressure in the reactor reach 0.3 mPa. The total amount of residual monomers in the polyethersulfone is 45 ppm, the total amount of residual solvent is 48 ppm, and the K ion content is 45 ppm.

[0084] Molecular structure characterization: The weight average molecular weight of polyethersulfone is 97130 g / mol, and the molecular weight distribution is 1.80. After being irradiated with gamma rays at an intensity of 75 kGy / h for 30 minutes, M2 / M1=78.5%.

[0085] Comparative Example 3

[0086] Commercially available polyethersulfone grade F2050 was purchased from Youju New Materials Co., Ltd., and the total amount of residual monomers, the total amount of residual solvents, and the K ion content were 32 ppm, 62 ppm, and 78 ppm, respectively.

[0087] Molecular structure characterization: The weight average molecular weight of polyethersulfone is 92250 g / mol, and the molecular weight distribution is 1.86. After being irradiated with gamma rays at an intensity of 75 kGy / h for 30 minutes, M2 / M1=76.8%.

Claims

1. A medical polyethersulfone, whose structure is shown in Formula 1: It is characterized in that after being sterilized by γ-ray irradiation, it satisfies the following formula: x = M2 / M1 > 85%; preferably, x = M2 / M1 > 98%; wherein, M1 is the weight-average molecular weight measured by GPC before the polyethersulfone is sterilized by γ-ray irradiation, and M2 is the weight-average molecular weight measured by GPC after the polyethersulfone is sterilized by γ-ray irradiation.

2. The medical polyethersulfone according to claim 1, it is characterized in that the total amount of residual monomers in the medical polyethersulfone < 20 ppm, the residual solvent < 20 ppm, and the metal ion content < 50 ppm.

3. The medical polyethersulfone according to claim 1 or 2, it is characterized in that the γ-ray irradiation sterilization is carried out under normal temperature, normal pressure and static conditions, the γ-ray irradiation intensity is 10 - 150 kGy / h, and the irradiation treatment time is 5 min to 48 h.

4. The medical polyethersulfone according to any one of claims 1 - 3, it is characterized in that the weight-average molecular weight measured by GPC before the polyethersulfone is sterilized by γ-ray irradiation is between 40,000 and 200,000 g / mol, preferably 40,000 - 120,000 g / mol.

5. A preparation method of the medical polyethersulfone according to any one of claims 1 - 4, it is characterized in that it includes the following steps: Dissolve monomer one and monomer two in the first organic solvent, then add the salt-forming agent and the second organic solvent to the reaction kettle in portions or continuously under stirring, carry out the salt-forming reaction for 2 - 6 h, the salt-forming reaction temperature is 140 - 210 °C, after the salt-forming reaction is completed, raise the temperature to completely distill out the second solvent in the reaction kettle, then react at 160 - 230 °C for 2 - 48 h, then add the first organic solvent for dilution, add the end-capping agent, and then filter press, crush, wash and dry the reaction liquid to obtain the medical polyethersulfone.

6. The preparation method according to claim 5, it is characterized in that the monomer one is any one of bisphenol S, bisphenol A, 4,4'-dihydroxybiphenyl; and / or the monomer two is dichlorodiphenyl sulfone; and / or the salt-forming agent is one or more of sodium hydroxide, potassium hydroxide, cesium hydroxide, potassium carbonate, sodium carbonate, barium carbonate, cesium carbonate, potassium bicarbonate, sodium bicarbonate; and / or the first organic solvent is one or more of N-methylpyrrolidone, dimethyl sulfone, diphenyl sulfone, sulfolane, N,N-dimethylformamide, N,N-dimethylacetamide; and / or the second organic solvent is one or more of toluene, xylene, o-xylene, mesitylene, chlorobenzene, dichlorobenzene; and / or the end-capping agent is one or more of chloromethane, 4-chlorophenyl phenyl sulfone.

7. The preparation method according to claim 5 or 6, it is characterized in that the molar ratio of the monomer one to the monomer two is 1.0 - 1.05:1; and / or the addition amount of the salt-forming agent is 1.05 - 1.5 times the molar amount of the monomer one; and / or the addition amount of the first organic solvent is 25 - 60 times the molar amount of the monomer one; and / or the addition amount of the second organic solvent is 10 - 50% of the mass of the first solvent; and / or The addition amount of the capping agent is 0.05 to 0.5 times the molar amount of the monomer; and / or; Preferably, the temperature of the salt-forming reaction is 180 to 200 °C, and the reaction time is 3 to 5 h.

8. The preparation method according to claim 5, characterized in that the capping agent is added or introduced in multiple equal or unequal portions, and the capping temperature is between 130 °C and 190 °C; Preferably, when the capping agent is chloromethane, the pipe for introducing chloromethane is perforated every 0.2 to 20 cm, and the pore diameter is 0.1 to 1 cm.

9. The preparation method according to claim 5, characterized in that the washing is carried out by boiling in water and / or washing with an aqueous solution of an organic solvent; Preferably, the organic solvent is selected from at least one of methanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and sulfolane, and the mass content of water in the aqueous solution of the organic solvent is preferably between 10% and 90%.

10. Use of the medical polyethersulfone according to any one of claims 1 to 4 or the medical polyethersulfone prepared by the preparation method according to any one of claims 5 to 9 in the field of medical devices, especially in the field of hemodialysis membranes.

Images