Antibacterial thermoplastic polyimide resin for medical catheter as well as preparation method and application of antibacterial thermoplastic polyimide resin

Abstract

The invention relates to the technical field of polyimide materials, in particular to antibacterial thermoplastic polyimide resin for medical catheters as well as a preparation method and application of the antibacterial thermoplastic polyimide resin. The antibacterial thermoplastic polyimide resin is synthesized from a diamine monomer modified by sulfobetaine and quaternary ammonium salt and dianhydride through a chemical imine method. In the molecular structural formula, R is any one of methyl, ethyl, propyl and butyl; y is any one element of Cl, Br and I; n and m are respectively any integer between 1 and 50; and z is any integer between 0 and 20. The antibacterial polyimide resin is suitable for the field of medical catheter materials, through the synergistic antibacterial effect of the two modified diamine monomers, microbial adhesion and biofilm formation on the surface of a medical catheter are effectively inhibited, and the antibacterial performance of polyimide is improved; the technical problem that an existing polyimide material is poor in antifouling, antibacterial and bactericidal performance can be effectively solved.

Description

Technical Field

[0001] This invention relates to the field of polyimide materials technology, and in particular to an antibacterial thermoplastic polyimide resin for medical catheters, its preparation method, and its application. Background Technology

[0002] With the rapid development of modern polymer medical devices, patients' quality of life has been significantly improved. However, at the same time, infection problems have become increasingly prominent. Indwelling urinary catheters, as a common invasive polymer medical device, play a vital role in disease treatment and improving the quality of medical care. Statistics show that the United States currently consumes approximately 30 million urinary catheters and 150 million endovascular catheters annually. With the popularization of minimally invasive surgery and the increase in the number of patients with cardiovascular and urinary system diseases, the use of medical catheters is showing a continuous upward trend. Patients requiring indwelling devices during medical or surgical treatments may develop healthcare-related infections due to bacteria adhering to the material surface. Approximately 60% to 70% of these infections are related to medical devices, with catheter-related urinary tract infections and catheter-related bloodstream infections being particularly common.

[0003] In recent years, polyimide materials have been increasingly widely used in the field of medical catheters. However, most existing polyimide medical catheters use commercially available general-purpose polyimide materials, which have poor antifouling and antibacterial properties. An ideal antibacterial surface should first prevent bacterial adhesion and biofilm formation through antifouling properties. Furthermore, it should possess bactericidal capabilities to rapidly kill pathogenic microorganisms that inevitably come into contact with or invade the surface, thereby achieving long-lasting antibacterial activity. Therefore, there is room for further optimization and improvement in existing methods for modifying the antibacterial properties of polyimides. There is a lack of polyimide materials specifically designed for medical antibacterial needs, and there is an urgent need to develop a polyimide material that combines antifouling and bactericidal functions. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an antibacterial thermoplastic polyimide resin for medical catheters, its preparation method, and its application. The present invention chemically modifies diamine monomers using sulfonate betaine and quaternary ammonium salts, and synthesizes block-modified antibacterial polyimide via a chemical imide method based on the two modified diamine monomers and aryl dianhydride. This enhances the antibacterial properties of the polyimide, effectively inhibiting microbial adhesion and biofilm formation on the surface of polyimide medical catheters, and effectively solving the technical problem of poor antifouling, antibacterial, and bactericidal properties of existing polyimide materials.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0006] An antibacterial thermoplastic polyimide resin for medical catheters is obtained by modifying a diamine monomer modified with sulfonate betaine and a diamine monomer modified with a quaternary ammonium salt, and has the molecular structure shown in Formula I:

[0007]

[0008] In Formula I, R is any one of methyl, ethyl, propyl, and butyl.

[0009] Y is any one of the elements Cl, Br, and I;

[0010] n and m can be any integers between 1 and 50;

[0011] z can be any integer between 0 and 20.

[0012] In some possible implementations, the ratio of n to m is any ratio between (0.6 to 1.5):1.

[0013] In some possible embodiments, the sulfobetaine-modified diamine monomer (BS-DA) has the molecular structure shown in Formula II:

[0014]

[0015] In Formula II, R is any one of methyl, ethyl, propyl, and butyl.

[0016] In some possible embodiments, the quaternary ammonium salt-modified diamine monomer (QAS-DA) has the molecular structure shown in Formula III:

[0017]

[0018] In Formula III, Y is any one of Cl, Br, and I; z takes any integer between 0 and 20.

[0019] In some possible implementations, in any of the molecular structural formulas of Formulas I to III:

[0020] Ar 1 Use any of the following structures:

[0021]

[0022] Ar 2 Use any of the following structures:

[0023]

[0024] Ar can use any of the following structures:

[0025]

[0026] The present invention also provides a method for preparing the antibacterial thermoplastic polyimide resin for medical catheters as described in any of the above embodiments, comprising the following steps:

[0027] S1, At room temperature, the diamine monomer modified with sulfonate betaine and the diamine monomer modified with quaternary ammonium salt are mixed and completely dissolved in a polar solvent to obtain a diamine monomer solution;

[0028] S2, the diamine monomer solution in step S1 is cooled and replaced with an inert gas. After the system stabilizes and reaches the set low temperature environment, the dianhydride monomer is slowly added under an inert gas atmosphere. After low-temperature stirring, a polyamic acid (PAA) solution is obtained.

[0029] S3, add an organic base to the polyamic acid solution in step S2, slowly add a dehydrating agent, then heat and stir to obtain a reaction solution;

[0030] S4. The reaction solution from step S3 is slowly added dropwise into an alcohol solvent, and a precipitate is immediately formed. The precipitate is then filtered under reduced pressure to obtain resin powder. The resin powder is then washed, filtered, and dried using an alcohol solvent to obtain antibacterial thermoplastic polyimide resin.

[0031] Furthermore, in step S1, the polar solvent is any one or more of DMF, DMAc, NMP, and DMSO.

[0032] In some possible embodiments, the sulfonate betaine-modified diamine monomer is prepared by the following steps:

[0033] (1) Add trihaloaromatic hydrocarbon, dialkylamine and base to polar solvent, stir at high temperature, after the reaction is completed, pour the reaction solution into water, filter to obtain solid, and after washing and drying, dialkylamine-substituted dihalohydrocarbon, i.e. intermediate 1;

[0034] (2) Add intermediate 1 from step (1) to a polar solvent and purge with nitrogen gas. After heating, add 1,3-propanesulfonyl lactone dropwise. After the reaction is complete, remove the solvent by rotary evaporation. After washing and drying, obtain intermediate 2.

[0035] (3) Add intermediate 2, aminophenol and base from step (2) to a polar solvent, stir at high temperature, remove the solvent by rotary evaporation after the reaction is completed, and obtain the diamine monomer modified with sulfonate betaine (BS-DA) after washing and drying.

[0036] In some possible implementations, in step (1), the trihaloaromatic hydrocarbon is selected from either 1,3,5-trichlorobenzene or 1,3,5-trifluorobenzene.

[0037] In some possible implementations, in step (1), the dialkylamine is selected from any one of dimethylamine hydrochloride, diethylamine, diisopropylamine, and dibutylamine.

[0038] In some possible implementations, in step (1), the molar ratio of trihalomethane to dialkylamine is (1-1.2):1.

[0039] In some possible implementations, in step (1), the molar ratio of dialkylamine to base is 1:(1-5).

[0040] Furthermore, in steps (1) and (3), the alkali is any one of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, sodium tert-butoxide, potassium tert-butoxide, and sodium hydride.

[0041] Furthermore, in steps (1) and (3), the polar solvent is any one of DMF, DMAc, and NMP.

[0042] Furthermore, in step (1), the amount of polar solvent added is calculated based on dialkylamine, the concentration of which is 0.1 to 1 mol / L.

[0043] Furthermore, in step (1), the reaction temperature is 80–150°C and the reaction time is 2–24 h.

[0044] Furthermore, in step (1), the volume of water is 5 times or more the volume of the polar solvent.

[0045] In some possible implementations, in step (2), the molar ratio of intermediate 1 to 1,3-propanesulfonyl lactone is 1:(1-2).

[0046] Furthermore, in step (2), the nitrogen purging time is 15 to 60 minutes.

[0047] Further, in step (2), the polar solvent is any one of methanol, ethanol, isopropanol, tert-butanol, trifluoroethanol, hexafluoroisopropanol, acetonitrile, tetrahydrofuran, dioxane, DMF, DMAc, and NMP.

[0048] Furthermore, in step (2), the amount of polar solvent added is calculated based on intermediate 1, the concentration of intermediate 1 in the polar solvent being 0.1 to 1 mol / L.

[0049] Furthermore, in step (2), the dropping time of 1,3-propanesulfonyl lactone is 0.5 to 6 hours.

[0050] Furthermore, in step (2), the reaction temperature is 40–70°C and the reaction time is 3–6 h.

[0051] Further, in step (2), the washing and drying process is as follows: the solid obtained after removing the solvent by rotary evaporation is washed three times with an ether solvent, and the remaining solid is vacuum dried for 6 to 12 hours.

[0052] Furthermore, in step (2), the ether solvent is any one of diethyl ether, methyl tert-butyl ether, or diethanol dimethyl ether.

[0053] In some possible implementations, in step (3), aminophenol is selected from either p-aminophenol or m-aminophenol.

[0054] In some possible implementations, in step (3), the molar ratio of intermediate 2 to aminophenol is 1:(2-4).

[0055] In some possible implementations, in step (3), the molar ratio of intermediate 2 to base is 1:(2-5).

[0056] Furthermore, in step (3), the reaction temperature is 80–150°C and the reaction time is 2–24 h.

[0057] Further, in step (3), the washing and drying process is as follows: after the reaction is completed, the solvent is removed by rotary evaporation, and then the solid is washed with a large amount of dichloromethane to obtain the solid. The dichloromethane is then removed by rotary evaporation, and the solid is washed three times with ether solvent. The remaining solid is then vacuum dried for 6 to 12 hours.

[0058] Furthermore, in step (3), the amount of dichloromethane used is determined by the absence of obvious fluorescent spots by TLC.

[0059] Furthermore, in step (3), the ether solvent is any one of diethyl ether, methyl tert-butyl ether, or diethanol dimethyl ether.

[0060] In some possible implementations, the quaternary ammonium salt-modified diamine monomer is prepared by the following steps:

[0061] (A) N,N-dimethylethanolamine, haloalkanes and organic solvents were mixed and heated to reflux. After the reaction was completed, the organic phases were extracted with ethyl acetate and water and combined. The organic phases were dried with a desiccant, filtered and then evaporated using a selective evaporator to remove the organic solvent, to obtain intermediate 3.

[0062] (B) Add intermediate 3, dihalobenzoic acid and acid catalyst to organic solvent, reflux and stir at high temperature, and use a water separator to separate water. After the reaction is completed, remove organic solvent by rotary evaporation and obtain intermediate 4 by recrystallization.

[0063] (C) Add intermediate 4, aminophenol, and base from step (B) to a polar solvent, stir at high temperature, and remove the solvent by rotary evaporation after the reaction is complete; after washing and drying, the quaternary ammonium salt modified diamine monomer (QAS-DA) is obtained.

[0064] In some possible implementations, in step (A), the haloalkane is selected from any one of bromopropane, bromobutane, bromopentane, bromohexane, bromoheptane, bromooctane, bromononane, bromodecane, bromoundecane, and bromododecane.

[0065] In some possible implementations, in step (A), the molar ratio of N,N-dimethylethanolamine to haloalkanes is (1-5):1.

[0066] Further, in step (A), the organic solvent is any one of methanol, ethanol, n-propanol, isopropanol, acetonitrile, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, methyl tert-butyl ether, and toluene.

[0067] Further, in step (A), the molar concentration of the haloalkane in the organic solvent is 0.01 to 1 mol / L.

[0068] Furthermore, in step (A), the reflux temperature is 60–120°C, and the reflux time is 2–24 h.

[0069] Furthermore, in step (A), the desiccant is anhydrous sodium sulfate or anhydrous magnesium sulfate.

[0070] In some possible implementations, in step (B), the dihalobenzoic acid is selected from either 3,5-difluorobenzoic acid or 3,5-dichlorobenzoic acid.

[0071] In some possible implementations, in step (B), the molar ratio of intermediate 3 to dihalobenzoic acid is (0.5-3):1.

[0072] Further, in step (B), the acid catalyst can be any one of sulfuric acid, methanesulfonic acid, or p-toluenesulfonic acid; the molar ratio of the acid catalyst to dihalobenzoic acid is (0.05–0.15):1.

[0073] Furthermore, in step (B), the organic solvent used is toluene or xylene.

[0074] Furthermore, in step (B), the reflux temperature is 110–160°C, and the reflux time is 2–24 h.

[0075] In some possible implementations, in step (C), aminophenol is selected from either p-aminophenol or m-aminophenol.

[0076] In some possible implementations, in step (C), the molar ratio of intermediate 4 to aminophenol is 1:(1-4).

[0077] In some possible implementations, in step (C), the base is selected from any one of sodium hydroxide, potassium hydroxide, potassium carbonate, cesium carbonate, sodium tert-butoxide, and potassium tert-butoxide.

[0078] In some possible implementations, in step (C), the molar ratio of intermediate 4 to base is 1:(1-5).

[0079] Furthermore, in step (C), the polar solvent is any one of NMP, DMF, or DMAc.

[0080] Furthermore, in step (C), the reaction temperature is 80–150°C, and the reaction time is 2–24 h.

[0081] Further, in step (C), the washing and drying process is as follows: after the reaction is completed, the solvent is removed by rotary evaporation, and then the solid is washed with a large amount of dichloromethane to obtain the solid. The dichloromethane is then removed by rotary evaporation, and the solid is washed three times with an ether solvent. The remaining solid is then vacuum dried for 6 to 12 hours.

[0082] Furthermore, in step (C), the amount of dichloromethane used can be determined by the absence of obvious fluorescence spots on TLC.

[0083] Furthermore, in step (C), the ether solvent can be any one of diethyl ether, methyl tert-butyl ether, or dimethyl diethanol ether.

[0084] In some possible embodiments, in step S2, the molar ratio of the diamine monomer to the dianhydride monomer is 1:(1.05-2), and the dianhydride monomer is an aryl dianhydride, employing any of the following structures:

[0085]

[0086] Furthermore, in step S2, the solid content of the polyamic acid solution is ≥5%.

[0087] Furthermore, in step S2, the inert gas is argon or nitrogen.

[0088] Furthermore, in step S2, the stirring temperature is between -10℃ and 5℃, and the stirring time is between 2 and 24 hours.

[0089] Further, in step S3, the organic base is any one or more of triethylamine, ethylenediamine, diisopropylethylamine, diethylamine, pyridine, 2,6-dimethylpyridine, 2,4,6-trimethylpyridine, 2,6-di-tert-butylpyridine, DMAP, and DBU.

[0090] Further, in step S3, the dehydrating agent is any one or more of acetic anhydride, propionic anhydride, acetyl chloride, dicyclohexylcarboimide (DCC), trifluoroacetic anhydride, and thionyl chloride.

[0091] Further, in step S3, the molar ratio of organic base to dehydrating agent is 1:(1-2), and the molar ratio of diamine monomer to dehydrating agent is 1:(2-8).

[0092] Furthermore, in step S3, the stirring temperature is 80–150°C, and the stirring time is 2–24 h.

[0093] Further, in step S4, the alcohol solvent is one or more of methanol, ethanol, propanol, isopropanol, hexafluoroisopropanol, butanol, tert-butanol, and acetone.

[0094] Furthermore, in step S4, the amount of alcohol solvent used is 2 to 50 times the volume of the polar solvent used in step S1.

[0095] The present invention also provides the application of the antibacterial thermoplastic polyimide resin in any of the above-described embodiments, or the antibacterial thermoplastic polyimide resin prepared by the preparation method described in any of the above-described embodiments, in medical catheter materials.

[0096] The present invention has the following beneficial effects:

[0097] This invention utilizes diamine monomers chemically modified with sulfonate betaine and quaternary ammonium salts to prepare antibacterial thermoplastic polyimide resins. The provided antibacterial thermoplastic polyimide resins are suitable for the field of medical catheter materials, exhibiting good antibacterial properties without damaging the mechanical properties of the materials. The resin side chains contain both sulfonate betaine and quaternary ammonium salts, combining zwitterionic sulfonate betaine and quaternary ammonium salts for synergistic antibacterial effects. This effectively reduces initial bacterial attachment and delays microbial colonization on the surface, thereby preventing biofilm formation. At the same time, it can rapidly kill invasive and contact pathogenic microorganisms, endowing the material with long-lasting bactericidal activity. Attached Figure Description

[0098] Figure 1 The image shows a comparison of the antibacterial test results of the resin powders obtained in Examples 1-4 and Comparative Example 1. Detailed Implementation

[0099] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention will be presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments.

[0100] Currently, methods for modifying the antibacterial properties of polyimide typically employ single antibacterial structures such as sulfonate betaine zwitterions. An ideal antibacterial surface should first prevent bacterial adhesion and biofilm formation through its antifouling properties. Furthermore, it should possess bactericidal capabilities, rapidly killing pathogenic microorganisms that inevitably come into contact with or invade the surface, thereby achieving long-lasting antibacterial activity. Therefore, there is room for further optimization and improvement in existing methods for modifying the antibacterial properties of polyimide to achieve superior antibacterial effects.

[0101] To address the aforementioned issues, this invention provides an antibacterial thermoplastic polyimide resin for medical catheters. This resin material combines zwitterionic sulfobetaine and quaternary ammonium salt, possessing both antifouling and bactericidal functions. Through the synergistic antibacterial effect of the two modified diamine monomers, it effectively inhibits microbial adhesion and biofilm formation on the surface of medical catheters. This antibacterial thermoplastic polyimide material is suitable for the field of medical catheter materials.

[0102] Example

[0103] An embodiment of the present invention provides an antibacterial thermoplastic polyimide resin for medical catheters, which is modified from a diamine monomer modified with sulfonate betaine and a diamine monomer modified with a quaternary ammonium salt, and has the molecular structure shown in Formula I:

[0104]

[0105] In Formula I, R is any one of methyl, ethyl, propyl, and butyl.

[0106] Y is any one of the elements Cl, Br, and I;

[0107] n and m can be any integers between 1 and 50;

[0108] z can be any integer between 0 and 20.

[0109] In some embodiments, the ratio of n to m is any ratio between (0.6 to 1.5):1.

[0110] In some embodiments, the sulfobetaine-modified diamine monomer (BS-DA) has the molecular structure shown in Formula II:

[0111]

[0112] In Formula II, R is any one of methyl, ethyl, propyl, and butyl.

[0113] In some embodiments, the quaternary ammonium salt-modified diamine monomer (QAS-DA) has the molecular structure shown in Formula III:

[0114]

[0115] In Formula III, Y is any one of Cl, Br, and I; z takes any integer between 0 and 20.

[0116] In some embodiments, in any of the molecular structural formulas of Formulas I to III:

[0117] Ar 1 Use any of the following structures:

[0118]

[0119] Ar 2 Use any of the following structures:

[0120]

[0121] Ar can use any of the following structures:

[0122]

[0123] The present invention also provides a method for preparing the antibacterial thermoplastic polyimide resin for medical catheters as described in any of the above embodiments, comprising the following steps:

[0124] S1, At room temperature, the diamine monomer modified with sulfonate betaine and the diamine monomer modified with quaternary ammonium salt are mixed and completely dissolved in a polar solvent to obtain a diamine monomer solution;

[0125] S2, the diamine monomer solution in step S1 is cooled and replaced with an inert gas. After the system stabilizes and reaches the set low temperature environment, the dianhydride monomer is slowly added under an inert gas atmosphere. After low-temperature stirring, a polyamic acid (PAA) solution is obtained.

[0126] S3, add an organic base to the polyamic acid solution in step S2, slowly add a dehydrating agent, then heat and stir to obtain a reaction solution;

[0127] S4. The reaction solution from step S3 is slowly added dropwise into an alcohol solvent, and a precipitate is immediately formed. The precipitate is then filtered under reduced pressure to obtain resin powder. The resin powder is then washed, filtered, and dried using an alcohol solvent to obtain antibacterial thermoplastic polyimide resin.

[0128] In step S1, the polar solvent is any one or more of DMF, DMAc, NMP, and DMSO.

[0129] The preparation route for the diamine monomer modified with the above-mentioned sulfonate betaine is as follows:

[0130]

[0131] X can be any one of F, Cl, or Br;

[0132] R is any one of methyl, ethyl, propyl, or butyl.

[0133] Specifically, the diamine monomer modified with sulfonate betaine is prepared through the following steps:

[0134] (1) Add trihaloaromatic hydrocarbon, dialkylamine and base to a polar solvent and stir at 80-150℃ for 2-24h. After the reaction is completed, pour the reaction solution into water, filter to obtain solid, and after washing and drying, obtain dialkylamine-substituted dihalohydrocarbon, i.e. intermediate 1.

[0135] (2) Add intermediate 1 from step (1) to a polar solvent and purge with nitrogen gas. React at 40-70°C for 3-6 hours. Add 1,3-propanesulfonyl lactone dropwise during the reaction. After the reaction is complete, remove the solvent by rotary evaporation. After washing and drying, obtain intermediate 2 modified with sulfonate betaine.

[0136] (3) Add intermediate 2, aminophenol and base from step (2) to a polar solvent and react at 80-150℃ for 2-24 hours. After the reaction is completed, remove the solvent by rotary evaporation, and obtain the diamine monomer modified with sulfonate betaine (BS-DA) after washing and drying.

[0137] In some possible implementations, in step (1), the trihaloaromatic hydrocarbon is selected from either 1,3,5-trichlorobenzene or 1,3,5-trifluorobenzene.

[0138] In some possible implementations, in step (1), the dialkylamine is selected from any one of dimethylamine hydrochloride, diethylamine, diisopropylamine, and dibutylamine.

[0139] In step (1), the molar ratio of trihalomethane to dialkylamine is (1-1.2):1.

[0140] In step (1), the molar ratio of dialkylamine to base is 1:(1-5).

[0141] In steps (1) and (3), the alkali is any one of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, sodium tert-butoxide, potassium tert-butoxide, and sodium hydride.

[0142] In steps (1) and (3), the polar solvent is any one of DMF, DMAc, and NMP.

[0143] In step (1), the amount of polar solvent added is calculated based on dialkylamine, the concentration of which is 0.1 to 1 mol / L.

[0144] In step (1), the volume of water is 5 times or more the volume of the polar solvent.

[0145] In step (2), the molar ratio of intermediate 1 to 1,3-propanesulfonyl lactone is 1:(1-2).

[0146] In step (2), the nitrogen gas is introduced for 15 to 60 minutes.

[0147] In step (2), the polar solvent is any one of methanol, ethanol, isopropanol, tert-butanol, trifluoroethanol, hexafluoroisopropanol, acetonitrile, tetrahydrofuran, dioxane, DMF, DMAc, and NMP.

[0148] In step (2), the amount of polar solvent added is calculated based on intermediate 1, the concentration of intermediate 1 in the polar solvent is 0.1 to 1 mol / L.

[0149] In step (2), the dripping time of 1,3-propanesulfonyl lactone can be 0.5 to 6 hours.

[0150] In step (2), the washing and drying process is as follows: the solid obtained after removing the solvent by rotary evaporation is washed three times with an ether solvent, and the remaining solid is vacuum dried for 6 to 12 hours.

[0151] In step (2), the ether solvent is any one of diethyl ether, methyl tert-butyl ether, or diethanol dimethyl ether.

[0152] In step (3), aminophenol is selected from either p-aminophenol or m-aminophenol.

[0153] In step (3), the molar ratio of intermediate 2 to aminophenol is 1:(2-4).

[0154] In step (3), the molar ratio of intermediate 2 to base is 1:(2-5).

[0155] In step (3), the washing and drying process is as follows: after the reaction is completed, the solvent is removed by rotary evaporation, and then the solid is washed with a large amount of dichloromethane. The dichloromethane is then removed by rotary evaporation, and the solid is washed three times with ether solvent. The remaining solid is then vacuum dried for 6 to 12 hours.

[0156] In step (3), the amount of dichloromethane used was determined by the absence of obvious fluorescence spots by TLC.

[0157] In step (3), the ether solvent is any one of diethyl ether, methyl tert-butyl ether, or dimethyl diethanol ether.

[0158] The preparation route for the quaternary ammonium salt-modified diamine monomers described above is as follows:

[0159]

[0160] Wherein, X can be any one of F, Cl, or Br;

[0161] Y is any one of the elements Cl, Br, and I;

[0162] z can be any integer between 0 and 20.

[0163] Specifically, the quaternary ammonium salt-modified diamine monomer is prepared through the following steps:

[0164] (A) After mixing N,N-dimethylethanolamine, haloalkanes and organic solvents, the mixture was refluxed at 60-120°C for 2-24 hours. After the reaction was completed, the organic phases were extracted with ethyl acetate and water and combined. The mixture was dried with a desiccant, filtered, and then the organic solvent was removed by selective evaporation to obtain intermediate 3.

[0165] (B) Add intermediate 3, dihalobenzoic acid and acid catalyst to an organic solvent, reflux at 110-160°C for 2-24 hours, and use a water separator to separate water. After the reaction is completed, remove the organic solvent by rotary evaporation and obtain intermediate 4 by recrystallization.

[0166] (C) Add intermediate 4, aminophenol, and base from step (B) to a polar solvent and react at 80–150 °C for 2–24 h. After the reaction is complete, remove the solvent by rotary evaporation. After washing and drying, obtain the quaternary ammonium salt modified diamine monomer (QAS-DA).

[0167] In step (A), the haloalkane is selected from any one of bromopropane, bromobutane, bromopentane, bromohexane, bromoheptane, bromooctane, bromononane, bromodecane, bromoundecane, and bromododecane.

[0168] In step (A), the molar ratio of N,N-dimethylethanolamine to haloalkanes is (1-5):1.

[0169] In step (A), the organic solvent is any one of methanol, ethanol, n-propanol, isopropanol, acetonitrile, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, methyl tert-butyl ether, and toluene.

[0170] In step (A), the molar concentration of the haloalkane in the organic solvent is 0.01 to 1 mol / L.

[0171] In step (A), the desiccant is anhydrous sodium sulfate or anhydrous magnesium sulfate.

[0172] In step (B), the dihalobenzoic acid is selected from either 3,5-difluorobenzoic acid or 3,5-dichlorobenzoic acid.

[0173] In step (B), the molar ratio of intermediate 3 to dihalobenzoic acid is (0.5-3):1.

[0174] In step (B), the acid catalyst can be any one of sulfuric acid, methanesulfonic acid, or p-toluenesulfonic acid; the molar ratio of the acid catalyst to dihalobenzoic acid is (0.05–0.15):1.

[0175] In step (B), the organic solvent used is toluene or xylene.

[0176] In step (C), aminophenol is selected from either p-aminophenol or m-aminophenol.

[0177] In step (C), the molar ratio of intermediate 4 to aminophenol is 1:(1-4).

[0178] In step (C), the base is selected from any one of sodium hydroxide, potassium hydroxide, potassium carbonate, cesium carbonate, sodium tert-butoxide, and potassium tert-butoxide.

[0179] In step (C), the molar ratio of intermediate 4 to base is 1:(1-5).

[0180] In step (C), the polar solvent is any one of NMP, DMF, or DMAc.

[0181] In step (C), the washing and drying process is as follows: after the reaction is completed, the solvent is removed by rotary evaporation, and then the solid is washed with a large amount of dichloromethane to obtain the solid. The dichloromethane is then removed by rotary evaporation, and the solid is washed three times with ether solvent. The remaining solid is then vacuum dried for 6 to 12 hours.

[0182] In step (C), the amount of dichloromethane used can be determined by the absence of obvious fluorescence spots by TLC.

[0183] In step (C), the ether solvent can be any one of diethyl ether, methyl tert-butyl ether, or diethanol dimethyl ether.

[0184] In some embodiments, in step S2, the molar ratio of the diamine monomer to the dianhydride monomer is 1:(1.05-2), and the dianhydride monomer is an aryl dianhydride, employing any one of the following structures:

[0185]

[0186] In step S2, the solid content of the polyamic acid solution is ≥5%.

[0187] In step S2, the inert gas is argon or nitrogen.

[0188] In step S2, the stirring temperature is between -10℃ and 5℃, and the stirring time is between 2 and 24 hours.

[0189] In step S3, the organic base is any one or more of triethylamine, ethylenediamine, diisopropylethylamine, diethylamine, pyridine, 2,6-dimethylpyridine, 2,4,6-trimethylpyridine, 2,6-di-tert-butylpyridine, DMAP, and DBU.

[0190] In step S3, the dehydrating agent is any one or more of acetic anhydride, propionic anhydride, acetyl chloride, dicyclohexylcarboimide (DCC), trifluoroacetic anhydride, and thionyl chloride.

[0191] In step S3, the molar ratio of organic base to dehydrating agent is 1:(1-2), and the molar ratio of diamine monomer to dehydrating agent is 1:(2-8).

[0192] In step S3, the stirring temperature is 80–150°C, and the stirring time is 2–24 h.

[0193] In step S4, the alcohol solvent is one or more of methanol, ethanol, propanol, isopropanol, hexafluoroisopropanol, butanol, tert-butanol, and acetone.

[0194] In step S4, the amount of alcohol solvent used is 2 to 50 times the volume of polar solvent used in step S1.

[0195] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention are described in further detail below. Unless otherwise specified, the raw materials used in the following examples are all commercially available products, and the reagents are analytical grade reagents.

[0196] Preparation Example 1

[0197] This preparation example provides a sulfonate betaine-modified aromatic diamine monomer with the following structural formula:

[0198]

[0199] The synthetic route for the sulfonate betaine-modified aromatic diamine monomer is as follows:

[0200]

[0201] The specific preparation steps are as follows:

[0202] (1) 1,3,5-trichlorobenzene (10 mmol, 1.81 g), dimethylamine hydrochloride (10 mmol, 0.815 g) and potassium carbonate (30 mmol, 4.15 g) were added to 50 mL of DMF and stirred at 100 °C for 12 h. After the reaction was completed, the reaction solution was poured into 500 mL of water to precipitate the solid. The solid obtained after filtration was washed three times with water and methanol respectively, and then dried in a vacuum oven at 75 °C for 12 h to obtain dimethylamine-substituted dihalohydrocarbon (intermediate 1).

[0203] (2) Add intermediate 1 (10 mmol, 1.9 g) to 20 mL of methanol and purge with nitrogen for 30 min. Then add 1,3-propanesulfonyl lactone (12 mmol, 1.47 g) dropwise at 65 °C until the addition is completed within the reaction time. After the reaction is completed, remove the solvent by rotary evaporation. The obtained solid is washed three times with diethyl ether and then dried under vacuum for 12 h to obtain intermediate 2.

[0204] (3) Intermediate 2 (10 mmol, 3.12 g), p-aminophenol (22 mmol, 2.4 g), and potassium carbonate (25 mmol, 3.46 g) were added to 30 mL of NMP and stirred at 120 °C for 12 h. After the reaction was completed, the solvent was removed by rotary evaporation, and the solid was washed with a large amount of dichloromethane. The dichloromethane was removed by rotary evaporation, and the solid was washed three times with diethyl ether and then dried under vacuum for 12 h to obtain the diamine monomer modified with sulfonate betaine (BS-DA).

[0205] The NMR data of the sulfonate betaine-modified aromatic diamine monomer prepared in this embodiment are as follows:

[0206] 1 H NMR (400MHz, DMSO-d6) δ 6.80–6.69 (m, 4H), 6.58–6.46 (m, 7H), 3.54 (s, 6H), 3.22 (t, J = 5.6Hz, 2H), 2.47 (t, J = 5.9Hz, 2H), 2.29 (p, J = 5.8Hz, 2H).

[0207] Preparation Example 2

[0208] This preparation example provides a quaternary ammonium salt modified aromatic diamine monomer with the following structural formula:

[0209]

[0210] The synthetic route for the quaternary ammonium salt-modified aromatic diamine monomer is as follows:

[0211]

[0212] The specific preparation steps are as follows:

[0213] (A) N,N-dimethylethanolamine (11 mmol, 0.98 g), bromododecane (10 mmol, 2.51 g) and ethanol (20 mL) were mixed thoroughly and heated under reflux for 20 h. After the reaction was completed, the mixture was extracted with ethyl acetate (50 mL / time, 3 times) and water (200 mL) in sequence. The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the organic solvent was removed by selective evaporation to obtain intermediate 3.

[0214] (B) Intermediate 3 (11 mmol, 3.72 g), dichlorobenzoic acid (10 mmol, 1.91 g), and methanesulfonic acid (1 mmol, 0.096 g) were added to toluene and stirred under reflux at 130 °C for 12 h. Water was separated using a water separator. After the reaction was completed, toluene was removed by rotary evaporation and intermediate 4 was obtained by recrystallization.

[0215] (C) Intermediate 4 (10 mmol, 5.08 g), p-aminophenol (11 mmol, 1.2 g), and NaOH (20 mmol) were added to 10 mL of NMP and stirred at 120 °C for 12 h. After the reaction was completed, the solvent was removed by vacuum distillation using a rotary evaporator. The solid was then washed with a large amount of dichloromethane. The dichloromethane solution was collected and the dichloromethane was removed by rotary evaporation to obtain the solid. The solid was washed three times with diethyl ether and the remaining solid was dried under vacuum for 12 h to obtain the quaternary ammonium salt modified diamine monomer (QAS-DA).

[0216] The NMR data of the quaternary ammonium salt-modified diamine monomer prepared in this embodiment are as follows:

[0217] 1 H NMR (400MHz, DMSO-d6) δ7.21(dt,J=12.6,2.1Hz,2H),6.95(t,J=2.0Hz,1H),6.87–6.80(m,2H),6.79–6.72(m,2H),6.62–6.50(m,4H),4.69(t,J =3.9Hz,2H),3.70(t,J=3.9Hz,2H),3.22(t,J=7.7Hz,2H),2.87(s,3H), 2.68(s,3H),1.51–1.39(m,2H),1.36–1.18(m,18H),0.95–0.79(m,3H).

[0218] Example 1

[0219] This embodiment provides a sulfonate betaine-modified antibacterial thermoplastic polyimide resin (BSPI), with the following structural formula:

[0220]

[0221] The specific preparation steps are as follows:

[0222] S1, At room temperature, 4.57 g (10 mmol) of the diamine monomer BS-DA synthesized in Preparation Example 1 was mixed with 100 ml of N-methylpyrrolidone (NMP) until completely dissolved to obtain a diamine monomer solution;

[0223] S2, the diamine monomer solution was cooled and purged with argon. The reaction solution was monitored with a thermometer. After the system temperature reached -5℃, 2.398 g (11 mmol) of pyromellitic dianhydride (PMDA) was slowly added under an inert gas atmosphere. The mixture was stirred at low temperature (-5℃) for 12 h. Then, 0.296 g of phthalic anhydride was added as a capping agent and the reaction was continued for 2 h to obtain a polyamic acid (PAA) solution.

[0224] S3, add 0.8 mL (10 mmol) of pyridine to PAA solution, and slowly add 1.88 mL (20 mmol) of acetic anhydride as a dehydrating agent. After the addition is complete, heat to 85 °C and stir for 16 h. The solution changes from transparent to light yellow reaction solution.

[0225] S4. The reaction solution from step S3 is slowly added dropwise to rapidly stirred methanol, and a light yellow precipitate is immediately precipitated. The precipitate is filtered under reduced pressure to obtain a light yellow resin powder. The light yellow resin powder is washed, filtered, and dried with methanol to obtain antibacterial thermoplastic polyimide resin.

[0226] The NMR data of the antibacterial thermoplastic polyimide resin prepared in this embodiment are as follows:

[0227] 1 H NMR (400MHz, DMSO-d6) δ8.33(d,J=5.9Hz,2H),8.18–8.10(m,2H),7.82–7.74(m,2H),7.07–7.00(m,2H),6.80–6.72(m,2H),6.54(t,J=2. 1Hz, 1H), 6.42 (t, J = 2.0Hz, 1H), 6.28 (t, J = 2.0Hz, 1H), 3.56 (s, 6H), 3.22 (t, J = 5.9Hz, 2H), 2.47 (t, J = 5.6Hz, 2H), 2.29 (p, J = 5.7Hz, 2H).

[0228] Example 2

[0229] This embodiment provides a quaternary ammonium salt modified antibacterial thermoplastic polyimide resin (QASPI), with the following structural formula:

[0230]

[0231] The specific preparation steps are as follows:

[0232] S1, At room temperature, 6.57 g (10 mmol) of the diamine monomer QAS-DA synthesized in Preparation Example 2 was mixed with 100 ml of N-methylpyrrolidone (NMP) until completely dissolved to obtain a diamine monomer solution.

[0233] S2, the diamine monomer solution was cooled and purged with argon. The reaction solution was monitored with a thermometer. After the system temperature reached -5℃, 2.398 g (11 mmol) of pyromellitic dianhydride (PMDA) was slowly added under an inert gas atmosphere. The mixture was stirred at low temperature (-5℃) for 12 h. Then, 0.296 g of phthalic anhydride was added as a capping agent and the reaction was continued for 2 h to obtain a polyamic acid (PAA) solution.

[0234] S3, add 0.8 mL (10 mmol) of pyridine to PAA solution, and slowly add 1.88 mL (20 mmol) of acetic anhydride as a dehydrating agent. After the addition is complete, heat to 85 °C and stir for 16 h. The solution changes from transparent to light yellow reaction solution.

[0235] S4. The reaction solution from step S3 is slowly added dropwise to rapidly stirred ethanol, and a light yellow precipitate is immediately precipitated. The precipitate is filtered under reduced pressure to obtain a light yellow resin powder. The light yellow resin powder is washed, filtered, and dried with ethanol to obtain antibacterial thermoplastic polyimide resin.

[0236] The NMR data of the antibacterial thermoplastic polyimide resin prepared in this embodiment are as follows:

[0237] 1 H NMR(400MHz, DMSO-d6)δ8.33(d,J=2.0Hz,2H),8.21–8.08(m,2H),7.86–7.72(m,2 H),7.25(dt,J=11.0,1.9Hz,2H),7.06–6.99(m,2H),6.97(t,J=2.0Hz,1H),6.88–6 .78(m,2H),4.69(t,J=4.0Hz,2H),3.70(t,J=4.0Hz,2H),3.22(t,J=7.7Hz,2H),2. 88(s,3H),2.74(s,3H),1.53–1.39(m,2H),1.35–1.19(m,18H),0.94–0.80(m,3H).

[0238] Example 3

[0239] This embodiment provides an antibacterial thermoplastic polyimide resin modified with sulfonate betaine and quaternary ammonium salt, with the following structural formula:

[0240]

[0241] The specific preparation steps are as follows:

[0242] S1, at room temperature, 2.29 g (5 mmol) of BS-DA synthesized in Preparation Example 1, 3.28 g (5 mmol) of diamine monomer QAS-DA synthesized in Preparation Example 2, and 100 ml of N-methylpyrrolidone (NMP) were mixed until completely dissolved to obtain a diamine monomer solution.

[0243] S2, the diamine monomer solution was cooled and purged with argon. The reaction solution was monitored with a thermometer. After the system temperature reached -5℃, 2.398 g (11 mmol) of pyromellitic dianhydride (PMDA) was slowly added under an inert gas atmosphere. The mixture was stirred at low temperature (-5℃) for 12 h. Then, 0.296 g of phthalic anhydride was added as a capping agent and the reaction was continued for 2 h to obtain a polyamic acid (PAA) solution.

[0244] S3, add 0.8 mL (10 mmol) of pyridine to PAA solution, and slowly add 1.88 mL (20 mmol) of acetic anhydride as a dehydrating agent. After the addition is complete, heat to 85 °C and stir for 16 h. The solution changes from transparent to light yellow reaction solution.

[0245] S4. The reaction solution from step S3 is slowly added dropwise to rapidly stirred ethanol, and a light yellow precipitate is immediately precipitated. The precipitate is filtered under reduced pressure to obtain a light yellow resin powder. The light yellow resin powder is washed, filtered, and dried with ethanol to obtain antibacterial thermoplastic polyimide resin.

[0246] The NMR data of the antibacterial thermoplastic polyimide resin prepared in this embodiment are as follows:

[0247] 1H NMR (400MHz, DMSO-d6) δ8.34(d,J=2.6Hz,4H),8.19–8.10(m,2H),8.10–8.02(m,2H),8.03–7.95(m,2H),7.80–7.71(m,2H),7.41(t,J =2.0Hz,1H),7.24–7.17(m,2H),7.15(t,J=2.0Hz,1H),7.10–7.02(m,3H),7.01–6.93(m,2H),6.71–6.64(m,2H),6.61(t,J=2.0Hz,1H ),6.50(t,J=2.0Hz,1H),6.20(t,J=2.0Hz,1H),4.69(t,J=3.8Hz,2H),3.70(t,J=3.8Hz,2H),3.64(d,J=8.5Hz,6H),3.30–3.13(m,4H ),2.77(s,3H),2.60(s,3H),2.47(t,J=5.8Hz,2H),2.29(p,J=5.8Hz,2H),1.50–1.40(m,2H),1.37–1.12(m,18H),0.93–0.80(m,3H).

[0248] Example 4

[0249] This embodiment provides an antibacterial polyimide modified by blending BS-modified polyimide (BSPI) and QAS-modified polyimide (QASPI). The structural formulas of the two polyimides are as follows:

[0250]

[0251] The preparation method of this blend-modified antibacterial polyimide is as follows:

[0252] The BSPI prepared in Preparation Example 1 and the QASPI prepared in Preparation Example 2 were mixed uniformly at a molar ratio of 1:1 and extruded through a twin-screw extruder to obtain a blended modified antibacterial polyimide material.

[0253] Example 5

[0254] This embodiment provides an antibacterial thermoplastic polyimide resin modified with sulfonate betaine and quaternary ammonium salt, with the following structural formula:

[0255]

[0256] The specific preparation steps are as follows:

[0257] S1, at room temperature, 2.29 g (5 mmol) of BS-DA synthesized in Preparation Example 1, 3.28 g (5 mmol) of diamine monomer QAS-DA synthesized in Preparation Example 2, and 100 ml of N-methylpyrrolidone (NMP) were mixed until completely dissolved to obtain a diamine monomer solution.

[0258] S2, the diamine monomer solution was cooled and purged with argon. The reaction solution was monitored with a thermometer. After the system temperature reached -5℃, 4.362 g (20 mmol) of pyromellitic dianhydride (PMDA) was slowly added under an inert gas atmosphere. The mixture was stirred at low temperature (-5℃) for 12 h. Then, 0.296 g of phthalic anhydride was added as a capping agent and the reaction was continued for 2 h to obtain a polyamic acid (PAA) solution.

[0259] S3, add 0.8 mL (10 mmol) of pyridine to PAA solution, and slowly add 1.88 mL (20 mmol) of acetic anhydride as a dehydrating agent. After the addition is complete, heat to 85 °C and stir for 16 h. The solution changes from transparent to light yellow reaction solution.

[0260] S4. The reaction solution from step S3 is slowly added dropwise to rapidly stirred ethanol, and a light yellow precipitate is immediately precipitated. The precipitate is filtered under reduced pressure to obtain a light yellow resin powder. The light yellow resin powder is washed, filtered, and dried with ethanol to obtain antibacterial thermoplastic polyimide resin.

[0261] The NMR data of the antibacterial thermoplastic polyimide resin prepared in this embodiment are as follows:

[0262] 1H NMR (400MHz, DMSO-d6) δ8.34(d,J=2.6Hz,4H),8.19–8.10(m,2H),8.10–8.02(m,2H),8.03–7.95(m,2H),7.80–7.71(m,2H),7.41(t,J =2.0Hz,1H),7.24–7.17(m,2H),7.15(t,J=2.0Hz,1H),7.10–7.02(m,3H),7.01–6.93(m,2H),6.71–6.64(m,2H),6.61(t,J=2.0Hz,1H ),6.50(t,J=2.0Hz,1H),6.20(t,J=2.0Hz,1H),4.69(t,J=3.8Hz,2H),3.70(t,J=3.8Hz,2H),3.64(d,J=8.5Hz,6H),3.30–3.13(m,4H ),2.77(s,3H),2.60(s,3H),2.47(t,J=5.8Hz,2H),2.29(p,J=5.8Hz,2H),1.50–1.40(m,2H),1.37–1.12(m,18H),0.93–0.80(m,3H).

[0263] Example 6

[0264] This embodiment provides an antibacterial thermoplastic polyimide resin modified with sulfonate betaine and quaternary ammonium salt, with the following structural formula:

[0265]

[0266] The specific preparation steps are as follows:

[0267] S1, at room temperature, 2.29 g (5 mmol) of BS-DA synthesized in Preparation Example 1, 3.28 g (5 mmol) of diamine monomer QAS-DA synthesized in Preparation Example 2, and 100 ml of N-methylpyrrolidone (NMP) were mixed until completely dissolved to obtain a diamine monomer solution.

[0268] S2, the diamine monomer solution was cooled and purged with argon. The reaction solution was monitored with a thermometer. After the system temperature reached -5℃, 3.412 g (11 mmol) of 4,4'-oxophthalic anhydride was slowly added under an inert gas atmosphere. The mixture was stirred at low temperature (-5℃) for 12 h. Then, 0.296 g of phthalic anhydride was added as a capping agent and the reaction was continued for 2 h to obtain a polyamic acid (PAA) solution.

[0269] S3, add 0.8 mL (10 mmol) of pyridine to PAA solution, and slowly add 1.88 mL (20 mmol) of acetic anhydride as a dehydrating agent. After the addition is complete, heat to 85 °C and stir for 16 h. The solution changes from transparent to light yellow reaction solution.

[0270] S4. The reaction solution from step S3 is slowly added dropwise to rapidly stirred ethanol, and a light yellow precipitate is immediately precipitated. The precipitate is filtered under reduced pressure to obtain a light yellow resin powder. The light yellow resin powder is washed, filtered, and dried with ethanol to obtain antibacterial thermoplastic polyimide resin.

[0271] The NMR data of the antibacterial thermoplastic polyimide resin prepared in this embodiment are as follows:

[0272] 1 H NMR(400MHz, DMSO-d6)δ8.14(dq,J=8.4,2.5Hz,4H),8.11–8.03(m,5H),7.86(d,J=7.5Hz,1H),7.79–7.69(m,2H),7.57(dq,J=4.2,2.0Hz,6H), 7.50(dd,J=7.5,1.9Hz,1H),7.44(d,J=1.9Hz,1H),7.22–7.15(m,2H),7.12(t,J=2.0Hz,1H),7.08–6.94(m,6H),6.87(t,J=2.1Hz,1H),6.81–6 .73(m,2H),6.65(t,J=2.0Hz,1H),6.50(t,J=2.0Hz,1H),4.69(t,J=3.7Hz,2H),3.70(t,J=3.7Hz,2H),3.64(s,3H),3.56(s,3H),3.26–3.18(m ,4H),3.07(s,3H),2.93(s,3H),2.47(t,J=6.4Hz,2H),2.34–2.24(m,2 H),1.45(tt,J=7.6,5.6Hz,2H),1.29–1.24(m,18H),0.92–0.81(m,3H).

[0273] Comparative Example 1

[0274] This comparative example provides a thermoplastic polyimide with the following structural formula:

[0275]

[0276] The specific preparation steps are as follows:

[0277] S1, At room temperature, 2.398 g (11 mmol) of pyromellitic dianhydride (PMDA) and 100 ml of N-methylpyrrolidone (NMP) were mixed until completely dissolved. The mixture was then cooled and purged with argon. The reaction solution was monitored with a thermometer. After the system temperature reached -5°C, 2.92 g (10 mmol) of 1,3-bis(4'-aminophenoxy)benzene (CAS: 2479-46-1) was slowly added under an inert gas atmosphere. The mixture was stirred at low temperature (-5°C) for 12 h. Then, 0.296 g of phthalic anhydride was added as a capping agent and the reaction was continued for 2 h to obtain a polyamic acid (PAA) solution.

[0278] S2, add 0.8 mL (10 mmol) of pyridine to PAA solution, and slowly add 1.88 mL (20 mmol) of acetic anhydride as a dehydrating agent. After the addition is complete, heat to 85 °C and stir for 16 h. The solution changes from transparent to light yellow reaction solution.

[0279] S3. The reaction solution from step S2 is slowly added dropwise to rapidly stirred ethanol, and a light yellow precipitate is immediately precipitated. The precipitate is filtered under reduced pressure to obtain a light yellow resin powder. The light yellow resin powder is washed, filtered, and dried with ethanol to obtain thermoplastic polyimide resin.

[0280] Performance testing

[0281] Test (I) Mechanical Property Test

[0282] The mechanical properties of the polyimide resins prepared in Examples 1-6 and Comparative Example 1 were tested according to the following standards:

[0283] The glass transition temperature T of the sample was tested in accordance with GB / T 19466.5-2022 "Differential Scanning Calorimetry (DSC) for Plastics - Part 5: Determination of Temperature, Time, Enthalpy and Conversion of Characteristic Reaction Curves". g and melting temperature and glass transition temperature T m ;

[0284] The tensile strength and elongation at break of the samples were tested in accordance with GB / T 1040.2-2022 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics".

[0285] The test results are shown in Table 1.

[0286] Table 1 Mechanical properties of polyimide resins

[0287]

[0288] Analysis of Table 1 shows that, compared with Comparative Example 1, Examples 1-4 have better mechanical properties, indicating that the side chains grafted with antibacterial groups help to significantly reduce the glass transition temperature of the material and improve its thermoplasticity. At the same time, the mechanical data of Examples 1-4 are similar, indicating that the simultaneous grafting of sulfonate betaine and quaternary ammonium salt onto the resin side chains does not damage the mechanical properties of the material.

[0289] Compared with Example 3, the overall performance of Example 5 is still better, but the tensile strength and elongation at break are worse. This may be because excessive acid anhydride hinders the imidization process and destroys the local imidization structure.

[0290] Compared to Example 3, Example 6 still performs better overall, but T g and T m The strength and mechanical properties are reduced. This may be because excessive aromatic ether structures increase structural flexibility while reducing structural strength.

[0291] Test (II) Antibacterial Performance Test

[0292] The specific antibacterial test method is as follows: The resin powders obtained in Examples 1-4 and Comparative Example 1 are dissolved in DMF solution respectively, and sterile filter paper with a diameter of 6 mm is soaked in the prepared solution to fully impregnate it. After the filter paper is removed and dried, it is spread flat on the agar inoculated with the bacterial strain, and the bacterial growth is observed after 7 days of growth in a constant temperature incubator at 37°C.

[0293] refer to Figure 1 Test results: The inhibition zone diameter of Example 3 was approximately 15 mm (sample diameter 6 mm), and the inhibition zone diameter of Example 4 was approximately 12 mm.

[0294] As can be seen, although both Examples 1 and 2 introduced antibacterial groups sulfonate betaine and quaternary ammonium salt onto their side chains, Example 1 only showed a very weak antibacterial effect after 7 days, Example 2 had a smaller inhibition zone, while Examples 3 and 4 were able to form larger inhibition zones. The antibacterial effect of the copolymerized sulfonate betaine and quaternary ammonium salt-modified antibacterial thermoplastic polyimide resin prepared in Example 3 was significantly better than that of the blended antibacterial thermoplastic polyimide resin prepared in Example 4. Therefore, the antibacterial effect of the copolymerized sulfonate betaine and quaternary ammonium salt-modified antibacterial thermoplastic polyimide resin is superior to that of polyimide resins modified with a single functional group or blended modification.

[0295] The mechanical and antibacterial performance test results show that the copolymerized sulfonate betaine and quaternary ammonium salt modified antibacterial thermoplastic polyimide resin provided by the present invention has excellent antibacterial and thermoplastic properties and can be used in the manufacture of interventional medical catheters.

[0296] Although the preferred embodiments of the present invention have been disclosed above, they are not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. An antibacterial thermoplastic polyimide resin for medical catheters, characterized in that, It is obtained by modification of diamine monomers modified with sulfonate betaine and diamine monomers modified with quaternary ammonium salts, and has the molecular structure shown in Formula I: In Formula I, R is any one of methyl, ethyl, propyl, and butyl. Y is any one of the elements Cl, Br, and I; n and m can be any integers between 1 and 50; z can be any integer between 0 and 20.

2. The antibacterial thermoplastic polyimide resin for medical catheters according to claim 1, characterized in that, The ratio of n to m is any ratio between (0.6 to 1.5):

1.

3. The antibacterial thermoplastic polyimide resin for medical catheters according to claim 1, characterized in that, The diamine monomer modified with sulfobetaine has the molecular structure shown in Formula II: In Formula II, R is any one of methyl, ethyl, propyl, and butyl.

4. The antibacterial thermoplastic polyimide resin for medical catheters according to claim 1, characterized in that, The quaternary ammonium salt-modified diamine monomer has the molecular structure shown in Formula III: In Formula III, Y is any one of Cl, Br, and I; z takes any integer between 0 and 20.

5. The antibacterial thermoplastic polyimide resin for medical catheters according to any one of claims 1 to 4, characterized in that, In any of the molecular structural formulas in Formulas I to III: Ar 1 Use any of the following structures: Ar 2 Use any of the following structures: Ar can use any of the following structures:

6. A method for preparing an antibacterial thermoplastic polyimide resin for medical catheters as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1, At room temperature, the diamine monomer modified with sulfonate betaine and the diamine monomer modified with quaternary ammonium salt are dissolved in a polar solvent to obtain a diamine monomer solution; S2, the diamine monomer solution in step S1 is cooled and replaced with an inert gas, dianhydride monomer is added, and polyamic acid solution is obtained after low-temperature stirring; S3, add an organic base to the polyamic acid solution in step S2, add a dehydrating agent dropwise, and then heat and stir to obtain a reaction solution; S4. The reaction solution from step S3 is added dropwise into an alcohol solvent. After the precipitate is formed, it is filtered under reduced pressure to obtain resin powder. The resin powder is then washed, filtered, and dried using an alcohol solvent to obtain antibacterial thermoplastic polyimide resin.

7. The method for preparing the antibacterial thermoplastic polyimide resin for medical catheters according to claim 6, characterized in that, The sulfonate-betaine-modified diamine monomer was prepared by the following steps: (1) Add trihaloaromatic hydrocarbon, dialkylamine and base to polar solvent, stir at high temperature, after the reaction is completed, pour the reaction solution into water, filter to obtain solid, and after washing and drying, obtain intermediate 1; (2) Add a polar solvent to intermediate 1 in step (1) and purge with nitrogen gas. After heating, add 1,3-propanesulfonyl lactone dropwise. After the reaction is complete, evaporate the solvent and wash and dry to obtain intermediate 2. (3) Add intermediate 2, aminophenol and base from step (2) to a polar solvent, stir at high temperature, and after the reaction is completed, evaporate the solvent, and after washing and drying, obtain the diamine monomer modified with sulfonate betaine. In step (1), the molar ratio of trihalomethane to dialkylamine is (1-1.2):1, and the molar ratio of dialkylamine to base is 1:(1-5). In step (2), the molar ratio of intermediate 1 to 1,3-propanesulfonyl lactone is 1:(1-2); In step (3), the molar ratio of intermediate 2 to aminophenol is 1:(2-4), and the molar ratio of intermediate 2 to base is 1:(2-5).

8. The method for preparing the antibacterial thermoplastic polyimide resin for medical catheters according to claim 6, characterized in that, The quaternary ammonium salt-modified diamine monomer is prepared through the following steps: (A) N,N-dimethylethanolamine, haloalkanes and organic solvents were mixed and heated to reflux; after the reaction was completed, the mixture was extracted, dried and filtered, and the organic solvent was evaporated to obtain intermediate 3. (B) Add intermediate 3, dihalobenzoic acid and acid catalyst to an organic solvent, reflux at high temperature, and after the reaction is completed, evaporate the organic solvent and recrystallize to obtain intermediate 4. (C) Add intermediate 4, aminophenol, and base from step (B) to a polar solvent, stir at high temperature, and after the reaction is complete, evaporate the solvent; after washing and drying, obtain the quaternary ammonium salt modified diamine monomer; In step (A), the molar ratio of N,N-dimethylethanolamine to haloalkanes is (1-5):1; In step (B), the molar ratio of intermediate 3 to dihalobenzoic acid is (0.5-3):1, and the molar ratio of acid catalyst to dihalobenzoic acid is (0.05-0.15):

1. In step (C), the molar ratio of intermediate 4 to aminophenol is 1:(1-4), and the molar ratio of intermediate 4 to base is 1:(1-5).

9. The method for preparing the antibacterial thermoplastic polyimide resin for medical catheters according to claim 6, characterized in that, In step S2, the molar ratio of the diamine monomer to the dianhydride monomer is 1:(1.05-2), and the dianhydride monomer is an aryl dianhydride, employing any one of the following structures:

10. The use of an antibacterial thermoplastic polyimide resin as described in any one of claims 1 to 5, or an antibacterial thermoplastic polyimide resin prepared by the preparation method as described in any one of claims 6 to 9, in medical catheter materials.

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