A diamine monomer, self-repairing thermoplastic polyimide resin and preparation method

Abstract

The present application relates to the technical field of high molecular compound, in particular to a kind of diamine monomer, self-repairing thermoplastic polyimide resin and preparation method.The molecular structure formula of the diamine monomer is, in the formula, Y is one of N atom or O atom, m is any integer between 1~5.The self-repairing thermoplastic polyimide resin prepared by the diamine monomer of the present application has the crosslinking structure of dynamic disulfide bond, compared with the structure containing disulfide bond in polyimide main chain, the polyimide resin of the present application has higher structural strength, and the performance after repair is better, which can effectively solve the technical problems of poor material self-repairing ability and poor mechanical properties of existing polyimide materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular compounds, in particular to a diamine monomer, a self-repairing thermoplastic polyimide resin and a preparation method. BACKGROUND

[0002] Polyimide (PI) has high thermal stability, good mechanical properties and excellent chemical properties, and is widely used in microelectronics, aerospace, energy storage, coating and other fields. At the same time, polyimide can be used as a dielectric protective layer and a passivation layer, and is applied to the packaging and manufacturing of important equipment microelectronic devices. In addition, polyimide is increasingly used as a medical catheter due to its high temperature resistance, corrosion resistance, low friction coefficient and good biocompatibility.

[0003] However, after the polyimide is formed into a catheter, the PI catheter formed as part of the functional components of a medical device is not only prone to micro-damage during post-processing and transportation, but also causes certain micro-damage to the catheter itself during use when it is assembled and combined with a guide wire and other parts. Therefore, it is necessary to develop a polyimide material with self-repairing function to avoid affecting the performance and use effect of the material due to some damage.

[0004] At present, the common polymer repair system through microcapsules or supramolecular forces has the problems of limited number of material repairs, insufficient material strength, poor mechanical properties and the like. In addition, dynamic covalent bond technology can also be used to repair polyimide. However, introducing too many flexible dynamic covalent bonds into the main chain of polyimide will reduce the structural strength of polyimide, limiting the application scenarios of polyimide materials. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a novel lipoic acid modified diamine monomer and a thermoplastic polyimide resin with self-repairing function synthesized based on the monomer and a preparation method thereof. The thermoplastic polyimide resin provided by the present application can effectively solve the technical problems of poor self-repairing ability and poor mechanical properties of existing polyimide materials.

[0006] In order to achieve the above technical purpose, the present application adopts the following technical solutions:

[0007] In one technical solution of the present application, a diamine monomer is provided, which has a molecular structure formula as shown in formula I:

[0008]

[0009] Formula I

[0010] In the formula, Y is one of N atom or O atom, and m is any integer between 1 and 5.

[0011] Another technical solution of the present application provides a preparation method of the above-mentioned diamine monomer, and the preparation route is as follows:

[0012]

[0013] Specifically includes the following steps:

[0014] S1: raw material 1, p-aminophenol, and an alkaline compound are added into a polar solvent, heated and stirred, after the reaction is completed, the reaction solution is poured into water, and a solid is obtained by filtration, and then washed and dried to obtain intermediate 1;

[0015] S2: intermediate 1, raw material 2, and an organic base are dissolved in dichloromethane, a condensing agent solution is slowly added dropwise into the dichloromethane solution, after stirring until the reaction is completed, the solution is diluted with ethyl acetate, and then washed with hydrochloric acid solution, saturated brine, and saturated sodium bicarbonate solution in sequence, the obtained solution is filtered with a drying agent, and then rotary evaporation is performed to obtain intermediate 2;

[0016] S3: intermediate 2, lipoic acid, and an organic base are dissolved in dichloromethane, a condensing agent solution is slowly added dropwise into the dichloromethane solution, after stirring until the reaction is completed, the solution is diluted with ethyl acetate, and then washed with hydrochloric acid solution, saturated brine, and saturated sodium bicarbonate solution in sequence, the obtained solution is filtered with a drying agent, and then rotary evaporation is performed to obtain the diamine monomer.

[0017] In some possible implementation manners, in step S1, the raw material 1 is any one of 2,6-dichlorobenzoic acid and 2,6-difluorobenzoic acid.

[0018] In some possible implementation manners, in step S1, the molar ratio of the raw material 1 to the p-aminophenol is 1: (1-5).

[0019] Preferably, in step S1, the molar ratio of the raw material 1 to the p-aminophenol is 1: (1.5-3).

[0020] In some possible implementation manners, in step S1, the alkaline compound 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.

[0021] In some possible implementation manners, in step S1, the molar ratio of the raw material 1 to the alkaline compound is 1: (1-5).

[0022] Preferably, in step S1, the molar ratio of the raw material 1 to the alkaline compound is 1: (2-4).

[0023] In some possible implementation manners, in step S1, the polar solvent is any one of DMF, DMAc, and NMP.

[0024] In some possible implementation manners, in step S1, the concentration of the raw material 1 in the polar solvent is 0.05-0.5 mol / L.

[0025] In some possible implementation manners, in step S1, the heating and stirring time is 2-24 h, and the heating temperature is 80-150 ℃.

[0026] In some possible implementation manners, in step S1, the amount of water is 2-5 times the volume of the polar solvent.

[0027] In some possible implementation manners, in step S2, the raw material 2 has a molecular structure as shown in Formula II.

[0028]

[0029] Formula II

[0030] In the formula, Y is one of N atom or O atom, and m is any integer between 1 and 5.

[0031] For example, in step S2, the raw material 2 can be HOCH2CH2OH, HOCH2(CH2)2OH, HOCH2(CH2)3OH, HOCH2(CH2)4OH, HOCH2(CH2)5OH, NH2CH2CH2NH2, NH2CH2(CH2)2NH2, NH2CH2(CH2)3NH2, NH2CH2(CH2)4NH2, or NH2CH2(CH2)5NH2.

[0032] In some possible implementation manners, in step S2, the molar ratio of the intermediate 1 to the raw material 2 is 1:(1-5).

[0033] Preferably, in step S2, the molar ratio of the intermediate 1 to the raw material 2 is 1:(1-3).

[0034] In some possible implementation manners, in step S2, the organic base is any one of pyridine, 2,6-dimethylpyridine, 2,6-di-tert-butylpyridine, 2,4,6-trimethylpyridine, 4-dimethylaminopyridine, and 4-pyrrolidinylpyridine.

[0035] In some possible implementation manners, in step S2, the molar ratio of the intermediate 1 to the organic base is 1:(1-5).

[0036] In some possible implementation manners, in step S2, the condensing agent is any one of N,N'-diisopropylcarbodiimide (DIC), dicyclohexylcarbodiimide (DCC), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI).

[0037] In some possible implementation manners, in step S2, the molar ratio of the intermediate 1 to the condensing agent is 1:(1-5).

[0038] In some possible implementation manners, in step S2, the solvent of the condensing agent solution is any one of DMF, DCM, DMAc, and NMP.

[0039] In some possible implementation manners, in step S2, the dropping speed of the condensing agent solution is 1-2 mL / min.

[0040] In some possible implementation manners, in step S2, the drying agent is any one of anhydrous sodium sulfate and anhydrous magnesium sulfate.

[0041] In some possible implementation manners, in step S2, the molar concentration of the raw material 1 in dichloromethane is 0.01-1 mol / L.

[0042] In some possible implementation manners, in step S2, the molar concentration of the raw material 1 in the solvent used by the condensing agent solution is 0.01-1 mol / L.

[0043] In some possible implementation manners, in step S2, the stirring reaction time is 2-24 h.

[0044] In some possible implementation manners, in step S2, the amount of ethyl acetate is 1-10 times the volume of the reaction solution.

[0045] In some possible implementation manners, in step S3, the molar ratio of lipoic acid to the intermediate 2 is 1:(1-5).

[0046] Preferably, in step S3, the molar ratio of lipoic acid to the intermediate 2 is 1:(1-3).

[0047] In some possible implementation manners, in step S3, the organic base is any one of pyridine, 2,6-dimethylpyridine, 2,6-di-tert-butylpyridine, 2,4,6-trimethylpyridine, 4-dimethylaminopyridine, and 4-pyrrolidinylpyridine.

[0048] In some possible implementation manners, in step S3, the molar ratio of lipoic acid to the organic base is 1:(1-5).

[0049] Preferably, in step S3, the molar ratio of lipoic acid to the organic base is 1:(1-3).

[0050] In some possible embodiments, in step S3, the condensing agent is any one of N,N'-diisopropylcarbodiimide (DIC), dicyclohexylcarbodiimide (DCC), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI).

[0051] In some possible embodiments, in step S3, the solvent of the condensing agent solution is any one of DMF, DCM, DMAc, and NMP.

[0052] In some possible embodiments, in step S3, the dropping speed of the condensing agent solution is 1-2 mL / min.

[0053] In some possible embodiments, in step S3, the molar ratio of lipoic acid to the condensing agent is 1:(1-5).

[0054] Preferably, in step S3, the molar ratio of lipoic acid to the condensing agent is 1:(1-3.5).

[0055] In some possible embodiments, in step S3, the drying agent is any one of anhydrous sodium sulfate and anhydrous magnesium sulfate.

[0056] In some possible embodiments, in step S3, the molar concentration of lipoic acid in dichloromethane is 0.01-1 mol / L.

[0057] In some possible embodiments, in step S3, the molar concentration of lipoic acid in the solvent used for the condensing agent solution is 0.01-1 mol / L.

[0058] In some possible embodiments, in step S3, the stirring reaction time is 2-24 h.

[0059] In some possible embodiments, in step S3, the amount of ethyl acetate is 1-10 times the volume of the reaction solution.

[0060] The application also provides a preparation method of a self-repairing thermoplastic polyimide resin, comprising the following steps:

[0061] (1) mixing a dianhydride monomer with a polar solvent at room temperature until completely dissolved; then performing cooling and inert gas replacement, adding a diamine monomer for low-temperature stirring to prepare a polyamide acid solution;

[0062] (2) adding an organic base to the polyamide acid solution prepared in step (1), then slowly adding a dehydrating agent, stirring after the addition is completed, slowly adding the obtained solution into an alcohol solvent after the reaction is completed, and precipitating a precipitate; obtaining a resin powder through reduced-pressure suction filtration, and washing, suction filtration, and drying the resin powder using an alcohol solvent to prepare a self-repairing thermoplastic polyimide resin.

[0063] In some possible embodiments, in step (1), the diamine monomer is prepared by using the diamine monomer described above or prepared by using the preparation method in any of the above schemes.

[0064] In some possible embodiments, in step (1), the dianhydride monomer is prepared by using an aryl dianhydride having any of the structures shown in the following formulas A1-A16:

[0065]

[0066] .

[0067] In some possible embodiments, in step (1), the molar ratio of the diamine monomer to the dianhydride monomer is 1: (1.05-2).

[0068] Preferably, in step (1), the molar ratio of the diamine monomer to the dianhydride monomer is 1: (1-1.5).

[0069] In some possible embodiments, in step (1), the polar solvent is any one or more of DMF, DMAc, NMP, and DMSO.

[0070] In some possible embodiments, in step (1), the molar concentration of the dianhydride monomer in the polar solvent is 0.01-0.5 mol / L.

[0071] In some possible embodiments, in step (1), the inert gas is any one of argon or nitrogen.

[0072] In some possible embodiments, in step (1), the solid content of the polyamic acid solution is ≥5%.

[0073] In some possible embodiments, in step (1), the temperature of the low-temperature stirring is ≤5°C, and the low-temperature stirring time is 2-24 h.

[0074] In some possible embodiments, in step (2), 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, 4-dimethylaminopyridine, and 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0075] In some possible embodiments, in step (2), the dehydrating agent is any one or more of acetic anhydride, propionic anhydride, acetyl chloride, dicyclohexylcarbodiimide, trifluoroacetic anhydride, and thionyl chloride.

[0076] In some possible implementation manners, in step (2), the molar ratio of the organic base to the dehydrating agent is 1: (1-4).

[0077] Preferably, in step (2), the molar ratio of the organic base to the dehydrating agent is 1: (1.5-3).

[0078] In some possible implementation manners, in step (2), the molar ratio of the dehydrating agent to the diamine monomer is (1-8): 1.

[0079] Preferably, in step (2), the molar ratio of the dehydrating agent to the diamine monomer is (1.5-4): 1.

[0080] In some possible implementation manners, in step (2), the dropping speed of the dehydrating agent is 1-2 mL / min.

[0081] In some possible implementation manners, in step (2), the alcohol solvent is one or more of methanol, ethanol, propanol, isopropanol, hexafluoroisopropanol, butanol, tert-butanol, and acetone.

[0082] In some possible implementation manners, in step (2), the amount of the alcohol solvent is 5-50 times the volume of the polar solvent.

[0083] In some possible implementation manners, in step (2), the temperature of the temperature-raising stirring is 65-150 ℃, and the temperature-raising stirring time is 2-24 h.

[0084] The application also provides a self-repairing thermoplastic polyimide resin prepared by the preparation method of any of the above technical solutions, which has a molecular structure formula as shown in formula III.

[0085]

[0086] Formula III

[0087] In formula III, Y is one of an N atom or an O atom, m is any integer between 1 and 5, n≥5, and x≥5. Preferably, n≥50 and x≥50; more preferably, n≥100 and x≥100.

[0088] In formula III, the Ar part has any one of the structures as shown in formula B1-B16.

[0089] .

[0090] The application has the following beneficial effects: the application modifies the molecular structure by introducing lipoic acid ester or lipoic acid amide in the diamine monomer structure, and uses the above-mentioned diamine monomer containing lipoic acid ester or lipoic acid amide and aryl dianhydride as starting materials to prepare a self-repairing thermoplastic polyimide resin by a chemical imidization method in a polar solvent. The polyimide resin provided by the application has a cross-linked structure of dynamic disulfide bonds, and compared with the structure containing disulfide bonds in the PI main chain, has better structural strength and mechanical properties, excellent self-repairing performance, and prolongs the service life of the polyimide product. The self-repairing performance of the disulfide bond can effectively repair some damage caused to the polyimide product in the processes of production, manufacturing, transportation, assembly and use, thereby ensuring the product performance and use effect. Especially when used as a medical catheter, the micro-damage caused in the processes of post-processing, transportation, assembly and use can be automatically repaired, thereby ensuring that the use effect of the product is not affected. BRIEF DESCRIPTION OF DRAWINGS

[0091] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, illustrate embodiments of the application, and are used to explain the application, and do not constitute a limitation on the application.

[0092] Figure 1 The self-repairing process diagram of the polyimide in Example 1 of the application is shown in Figure 1.

[0093] Figure 2 The self-repairing process diagram of the polyimide in Example 2 of the application is shown in Figure 2.

[0094] Figure 3 The self-repairing process diagram of the polyimide in Example 3 of the application is shown in Figure 3.

[0095] Figure 4 The self-repairing process diagram of the polyimide in Example 4 of the application is shown in Figure 4.

[0096] Figure 5 The self-repairing test process diagram of the polyimide prepared in Comparative Example 1 of the application is shown in Figure 5.

[0097] Figure 6 The self-repairing test process diagram of the polyimide prepared in Comparative Example 2 of the application is shown in Figure 6. DETAILED DESCRIPTION

[0098] In order to make the purpose, technical scheme and advantages of the application clearer, the embodiments of the application will be described below with reference to the drawings, and those skilled in the art can easily understand other advantages and effects of the application from the content disclosed in the specification. Although the description of the application will be introduced together with the preferred embodiments, this does not mean that the features of the application are limited to the embodiments. The raw materials used in the following examples are all ordinary commercially available goods, and the reagents are analytical pure reagents.

[0099] A lipoic acid modified diamine monomer is provided in the embodiments of the present application, which has a molecular structural formula as shown in formula I:

[0100]

[0101] Formula I

[0102] In formula I, Y is one of N atom or O atom, and m is an arbitrary integer between 1 and 5.

[0103] A synthesis route of the lipoic acid modified diamine monomer is as follows:

[0104]

[0105] A preparation method of the lipoic acid modified diamine monomer includes the following steps:

[0106] S1: raw material 1, p-aminophenol, and an alkaline compound are added into a polar solvent, and stirred at 80-150°C for 2-24h. After the reaction is completed, the reaction solution is poured into water, and a solid is obtained by filtration, and then washed and dried to obtain intermediate 1.

[0107] S2: intermediate 1, raw material 2, and an organic base are dissolved into dichloromethane, and then a condensing agent solution is slowly added dropwise into the dichloromethane solution, and stirred for 2-24h. After the reaction is completed, the solution is diluted with ethyl acetate, and then sequentially washed with hydrochloric acid solution, saturated brine, and saturated sodium bicarbonate solution. The obtained solution is filtered with a drying agent, and then rotary evaporated to obtain intermediate 2.

[0108] In some embodiments, the raw material 1 is any one of 2,6-dichlorobenzoic acid and 2,6-difluorobenzoic acid.

[0109] In some embodiments, the raw material 2 has a molecular structural formula as shown in formula II:

[0110]

[0111] Formula II

[0112] In formula II, Y is one of N atom or O atom, and m is an arbitrary integer between 1 and 5.

[0113] S3: intermediate 2, lipoic acid, and an organic base are dissolved into dichloromethane, and then a condensing agent solution is slowly added dropwise into the dichloromethane solution, and stirred for 2-24h. After the reaction is completed, the solution is diluted with ethyl acetate, and then sequentially washed with hydrochloric acid solution, saturated brine, and saturated sodium bicarbonate solution. The obtained solution is filtered with a drying agent, and then rotary evaporated to obtain the diamine monomer.

[0114] In some embodiments, the components and amounts are as follows:

[0115] In step S1:

[0116] The molar ratio of raw material 1 to p-aminophenol is 1: (1-5), preferably 1: (1.5-3);

[0117] The basic compound 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.

[0118] The molar ratio of raw material 1 to the basic compound is 1: (1-5), preferably 1: (2-4).

[0119] The polar solvent is any one of DMF, DMAc, and NMP.

[0120] The amount of water is 2-5 times the volume of the polar solvent.

[0121] In step S2:

[0122] The molar ratio of intermediate 1 to raw material 2 is 1: (1-5), preferably 1: (1-3);

[0123] The organic base is any one of pyridine, 2,6-dimethylpyridine, 2,6-di-tert-butylpyridine, 2,4,6-trimethylpyridine, 4-dimethylaminopyridine, and 4-pyrrolidinopyridine.

[0124] The molar ratio of intermediate 1 to the organic base is 1: (1-5).

[0125] The condensing agent is any one of N,N'-diisopropylcarbodiimide (DIC), dicyclohexylcarbodiimide (DCC), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI).

[0126] The molar ratio of intermediate 1 to the condensing agent is 1: (1-5).

[0127] The drying agent is any one of anhydrous sodium sulfate and anhydrous magnesium sulfate.

[0128] The molar concentration of raw material 1 in dichloromethane is 0.01-1 mol / L.

[0129] The solvent of the condensing agent solution is any one of DMF, DCM, DMAc, and NMP.

[0130] The dropping speed of the condensing agent solution is 1-2 mL / min.

[0131] The molar concentration of raw material 1 in the solvent used for the condensing agent solution is 0.01-1 mol / L.

[0132] The amount of ethyl acetate is 1-10 times of the volume of the reaction solution.

[0133] In step S3:

[0134] The molar ratio of lipoic acid to intermediate 2 is 1: (1-5), preferably 1: (1-3).

[0135] The organic base is any one of pyridine, 2,6-dimethylpyridine, 2,6-di-tert-butylpyridine, 2,4,6-trimethylpyridine, 4-dimethylaminopyridine, and 4-pyrrolidinopyridine.

[0136] The molar ratio of lipoic acid to organic base is 1: (1-5), preferably 1: (1-3).

[0137] The condensing agent is any one of N,N'-diisopropylcarbodiimide (DIC), dicyclohexylcarbodiimide (DCC), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI).

[0138] The molar ratio of lipoic acid to condensing agent is 1: (1-5), preferably 1: (1-3.5).

[0139] The drying agent is any one of anhydrous sodium sulfate and anhydrous magnesium sulfate.

[0140] The molar concentration of lipoic acid in dichloromethane is 0.01-1 mol / L.

[0141] The solvent of the condensing agent solution is any one of DMF, DCM, DMAc, and NMP.

[0142] The dropping speed of the condensing agent solution is 1-2 mL / min.

[0143] The molar concentration of lipoic acid in the solvent used for the condensing agent solution is 0.01-1 mol / L.

[0144] The amount of ethyl acetate is 1-10 times of the volume of the reaction solution.

[0145] The self-repairing thermoplastic polyimide resin prepared by using the lipoic acid-modified diamine monomer has a molecular structure as shown in Formula III.

[0146]

[0147] Formula III

[0148] In the formula, Y is one of N atom or O atom, m is any integer between 1 and 5, n≥5, and x≥5. Preferably, n≥50 and x≥50; more preferably, n≥100 and x≥100.

[0149] The Ar part of the above formula has any one of the structures shown in the following formulas B1-B16:

[0150]

[0151] The preparation method of the self-repairing thermoplastic polyimide resin comprises the following steps:

[0152] (1) At room temperature, the dianhydride monomer is mixed with a polar solvent until completely dissolved; then, cooling and inert gas replacement are performed, and after the system is stable and reaches a set low temperature environment (temperature ≤ 5℃), the above-mentioned diamine monomer is slowly added under an inert gas atmosphere for low-temperature stirring for 2-24h, and a capping agent is added for continued reaction for 2h, to obtain a polyamic acid solution;

[0153] (2) An organic base is added to the polyamic acid solution obtained in step (1), and then a dehydrating agent is added dropwise; after the dropwise addition is completed, the temperature is raised to 65-150℃ for stirring for 2-24h; after the reaction is completed, the obtained solution is slowly added to an alcohol solvent to precipitate a precipitate; the resin powder is obtained by reduced-pressure suction filtration, and then the resin powder is washed, suction filtered and dried using an alcohol solvent, to obtain a self-repairing thermoplastic polyimide resin.

[0154] In some embodiments, the dianhydride monomer is an aryl dianhydride, which has any one of the structures shown in the following formulas A1-A16:

[0155]

[0156]

[0157] In some embodiments, in step (1), the molar ratio of the diamine monomer to the dianhydride monomer is 1: (1.05-2), preferably 1: (1-1.5).

[0158] In some embodiments, in step (1), the polar solvent is any one or more of DMF, DMAc, NMP and DMSO.

[0159] In some embodiments, the molar concentration of the dianhydride monomer in the polar solvent is 0.01-0.5 mol / L.

[0160] In some embodiments, in step (1), the inert gas is any one of argon or nitrogen.

[0161] In some embodiments, in step (1), the capping agent is phthalic anhydride, and the amount of the capping agent is 15-25% of the mass of the diamine monomer. Preferably, the amount of the capping agent is 20% of the mass of the diamine monomer.

[0162] In some embodiments, in step (2), 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, 4-dimethylaminopyridine, and 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0163] In some embodiments, in step (2), the dehydrating agent is any one or more of acetic anhydride, propionic anhydride, acetyl chloride, dicyclohexylcarbodiimide, trifluoroacetic anhydride, and thionyl chloride.

[0164] In some embodiments, in step (2), the molar ratio of the organic base to the dehydrating agent is 1:(1-4), preferably 1:(1.5-3).

[0165] In some embodiments, in step (2), the molar ratio of the dehydrating agent to the diamine monomer is (1-8):1, preferably (1.5-4):1.

[0166] In some embodiments, in step (2), the dropping speed of the dehydrating agent is 1-2 mL / min.

[0167] In some embodiments, in step (2), the alcohol solvent is one or more of methanol, ethanol, propanol, isopropanol, hexafluoroisopropanol, butanol, tert-butanol, and acetone, and the amount of the alcohol solvent is 5-50 times the volume of the reaction solution.

[0168] Preparation Example 1

[0169] The present preparation example provides a diamine monomer, which is a 1,3-diarylether diamine modified by ethylene glycol-linked thioctic acid ester, and the molecular structural formula thereof is:

[0170]

[0171] The synthesis route of the above diamine monomer is as follows:

[0172]

[0173] The specific synthesis steps are as follows:

[0174] S1, 1.91 g (10 mmol) of 2,6-dichlorobenzoic acid (CAS No.: 50-30-6), 1.31 g (12 mmol) of p-aminophenol (CAS No.: 123-30-8), 1.2 g (30 mmol) of NaOH were added into 100 mL of NMP, stirred at 120°C for 12 h, after the reaction was completed, the reaction solution was filtered through diatomite and silica gel, then poured into a large amount of water, and the solid was obtained by filtration, washed and dried to obtain the intermediate 1. The molar ratio of 2,6-dichlorobenzoic acid to p-aminophenol was 1:1.2, and the molar ratio of 2,6-dichlorobenzoic acid to NaOH was 1:3.

[0175] S2, 3.36 g (10 mmol) of intermediate 1, 1.24 g (20 mmol) of ethylene glycol, 1.47 g (12 mmol) of 4-dimethylaminopyridine were dissolved in 70 mL of dichloromethane, and then 50 mL of a DMF solution containing 2.3 g (12 mmol) of EDCI was slowly added to the reaction solution at a speed of 1.5 mL / min, and stirred for 16 h. After the reaction was completed, it was diluted with 200 mL of ethyl acetate, and then washed with 100 mL of dilute hydrochloric acid solution, 100 mL of saturated brine, and 100 mL of saturated sodium bicarbonate solution, respectively. The obtained solution was dried with anhydrous magnesium sulfate and filtered, and then intermediate 2 was obtained by rotary evaporation. The molar ratio of intermediate 1 to ethylene glycol was 1:2, the molar ratio of intermediate 1 to 4-dimethylaminopyridine was 1:1.2, and the molar ratio of intermediate 1 to EDCI was 1:1.2.

[0176] S3, 2.06 g (10 mmol) of lipoic acid, 4.56 g (12 mmol) of intermediate 2, 1.47 g (12 mmol) of 4-dimethylaminopyridine were dissolved in 70 mL of dichloromethane, and then 50 mL of a DMF solution containing 2.3 g (12 mmol) of EDCI was slowly added to the reaction solution at a speed of 1.5 mL / min, and stirred for 16 h. After the reaction was completed, it was diluted with 200 mL of ethyl acetate, and then washed with 100 mL of dilute hydrochloric acid solution, 100 mL of saturated brine, and 100 mL of saturated sodium bicarbonate solution, respectively. The obtained solution was dried with anhydrous magnesium sulfate and filtered, and then the diamine monomer was obtained by rotary evaporation. The molar ratio of lipoic acid to intermediate 2 was 1:1.2, the molar ratio of lipoic acid to 4-dimethylaminopyridine was 1:1.21, and the molar ratio of lipoic acid to EDCI was 1:1.2.

[0177] NMR data:

[0178] 1H NMR (500 MHz, Chloroform-d) δ 7.41 (t, J = 7.5 Hz, 1H), 6.82 (d, J= 7.5 Hz, 2H), 6.75 – 6.68 (m, 4H), 6.64 – 6.58 (m, 4H), 5.28 (ddd, J = 12.4, 10.7, 1.9 Hz, 1H), 5.08 (ddd, J = 12.6, 10.8, 1.9 Hz, 1H), 3.87 (ddt, J = 12.3, 10.7, 1.5 Hz, 2H), 2.66 – 2.55 (m, 2H), 2.49 (dt, J = 12.6, 7.1 Hz, 1H), 2.34 (p, J = 7.0 Hz, 1H), 2.19 – 2.07 (m, 1H), 2.02 – 1.92 (m, 2H), 1.83 – 1.69 (m, 2H), 1.51 (ddt, J = 12.8, 6.8, 3.3 Hz, 1H), 1.31 (tdd, J = 14.3, 8.2, 2.6 Hz, 2H), 0.99 (dtd, J = 13.3, 11.4, 10.5, 3.1 Hz, 1H).

[0179] Preparation Example 2

[0180] This comparative example provides a diamine monomer, specifically a thioctic acid amide-modified 1,3-diarylether diamine linked by propylene diamine, which has the following molecular structure:

[0181]

[0182] The synthesis route of the above diamine monomer is as follows:

[0183]

[0184] The specific synthesis steps are as follows:

[0185] S1, 1.91 g (10 mmol) of 2,6-dichlorobenzoic acid (CAS No.: 50-30-6), 1.31 g (12 mmol) of p-aminophenol (CAS No.: 123-30-8), and 1.2 g (30 mmol) of NaOH were added to 100 mL of NMP, stirred at 120°C for 12 h, after the reaction was completed, the reaction solution was filtered through diatomite and silica gel, then poured into a large amount of water, and a solid was obtained by filtration, washed and dried to obtain the intermediate 1. The molar ratio of 2,6-dichlorobenzoic acid to p-aminophenol was 1:1.2, and the molar ratio of 2,6-dichlorobenzoic acid to NaOH was 1:3.

[0186] S2, 3.36 g (10 mmol) of intermediate 1, 1.48 g (20 mmol) of propylene diamine, and 1.47 g (12 mmol) of 4-dimethylaminopyridine were dissolved in 70 mL of dichloromethane, then 50 mL of a DMF solution containing 2.3 g (12 mmol) of EDCI was slowly added to the reaction solution at a rate of 1.5 mL / min, and stirred for 16 h. After the reaction was completed, the solution was diluted with 200 mL of ethyl acetate, then washed with 100 mL of dilute hydrochloric acid solution, 100 mL of saturated brine, and 100 mL of saturated sodium bicarbonate solution, respectively, the obtained solution was dried with anhydrous magnesium sulfate and filtered, then rotary evaporated to obtain the intermediate 2. The molar ratio of intermediate 1 to ethylene glycol was 1:2, the molar ratio of intermediate 1 to 4-dimethylaminopyridine was 1:1.2, and the molar ratio of intermediate 1 to EDCI was 1:1.2.

[0187] S3, 2.06 g (10 mmol) of lipoic acid, 4.7 g (12 mmol) of intermediate 2, and 1.47 g (12 mmol) of 4-dimethylaminopyridine were dissolved in 70 mL of dichloromethane, then 50 mL of a DMF solution containing 2.3 g (12 mmol) of EDCI was slowly added to the reaction solution at a rate of 1.5 mL / min, and stirred for 16 h. After the reaction was completed, the solution was diluted with 200 mL of ethyl acetate, then washed with 100 mL of dilute hydrochloric acid solution, 100 mL of saturated brine, and 100 mL of saturated sodium bicarbonate solution, respectively, the obtained solution was dried with anhydrous magnesium sulfate and filtered, then rotary evaporated to obtain the diamine monomer. The molar ratio of lipoic acid to intermediate 2 was 1:1.78, the molar ratio of lipoic acid to 4-dimethylaminopyridine was 1:1.21, and the molar ratio of lipoic acid to EDCI was 1:1.2.

[0188] Example 1

[0189] The present embodiment provides a self-repairing thermoplastic polyimide resin, and the molecular structure formula is as follows:

[0190]

[0191] The specific synthesis steps are as follows:

[0192] (1) At room temperature, 2.398 g (11 mmol) of pyromellitic dianhydride was mixed with 100 mL of NMP until completely dissolved; then, cooling was performed and argon replacement was performed, and the reaction solution was detected by thermometer, and after the system temperature reached -5 ℃, 5.68 g (10 mmol) of diamine monomer provided by Preparation Example 1 was slowly added under the condition of maintaining inert gas atmosphere, and after continuing low-temperature stirring for 12 h, 1.14 g of end-capping agent phthalic anhydride was added and reacted for 2 h to obtain a polyamic acid solution. The molar ratio of diamine to dianhydride was 1:1 by calculation.

[0193] (2) 0.8 mL (10 mmol) of pyridine was added to the polyamic acid solution prepared in step (1), and 1.88 mL (20 mmol) of acetic anhydride was slowly added at a rate of 1.5 mL / min, and after the addition was completed, the temperature was raised to 85 ℃ and stirred for 16 h, and after the reaction was completed, the light yellow solution obtained was added to 250 mL of rapidly stirred ethanol solvent, and light yellow precipitate was immediately precipitated. Light yellow resin powder was obtained by vacuum suction filtration, and the light yellow powder was washed, suction filtered and dried using ethanol to obtain a self-repairing thermoplastic polyimide resin. The molar ratio of pyridine to acetic anhydride was 1:2; the molar ratio of acetic anhydride to diamine monomer was 2:1 by calculation.

[0194] NMR data are as follows:

[0195] 1H NMR (500 MHz, Chloroform-d) δ 8.43 (s, 2H), 7.67 – 7.61 (m, 2H), 7.36 (d, J = 1.9 Hz, 2H), 7.33 – 7.27 (m, 2H), 6.97 – 6.92 (m, 2H), 6.87 (t, J = 2.0 Hz, 1H), 6.70 – 6.62 (m, 2H), 4.49 (d, J = 2.4 Hz, 4H), 2.60 (t, J = 7.0 Hz, 1H), 2.48 (t, J = 7.1 Hz, 1H), 2.40 – 2.30 (m, 3H), 2.08 (q, J = 7.1 Hz, 1H), 1.76 (q, J = 7.0 Hz, 1H), 1.72 – 1.54 (m, 3H), 1.28 (dq, J = 23.3, 7.0 Hz, 2H), 1.19 (p, J = 7.1 Hz, 1H).

[0196] Example 2

[0197] The present example provides a self-repairing thermoplastic polyimide resin, whose molecular structure is as follows:

[0198]

[0199] The specific synthesis steps are as follows:

[0200] (1) At room temperature, 2.398 g (11 mmol) of pyromellitic dianhydride was mixed with 100 mL of NMP until completely dissolved; then cooled and replaced with argon, and the reaction solution was detected by thermometer. When the system temperature reached -5°C, 5.8 g (10 mmol) of diamine monomer provided by Preparation Example 2 was slowly added under the condition of maintaining inert gas atmosphere. After continuing low-temperature stirring for 12 h, 1.16 g of end-capping agent phthalic anhydride was added for further reaction for 2 h, to obtain a polyamic acid solution. The molar ratio of diamine to dianhydride was calculated to be 1:1.

[0201] (2) 0.8 mL (10 mmol) of pyridine was added to the polyamic acid solution prepared in step (1), and then 1.88 mL (20 mmol) of acetic anhydride was slowly added at a speed of 1.5 mL / min. After the addition was completed, the temperature was raised to 85°C and stirred for 16 h. The solution color changed from transparent to light yellow. The light yellow solution was added to 250 mL of rapidly stirred ethanol solvent, and light yellow precipitate was immediately precipitated. Light yellow resin powder was obtained by vacuum filtration, and the light yellow powder was washed, filtered and dried with ethanol to obtain a self-repairing thermoplastic polyimide resin. The molar ratio of pyridine to acetic anhydride was calculated to be 1:2; the molar ratio of acetic anhydride to diamine monomer was 2:1.

[0202] Example 3

[0203] The present example provides a self-repairing thermoplastic polyimide resin, whose molecular structure is as follows:

[0204]

[0205] The specific synthesis steps are as follows:

[0206] (1) 3.54 g (11 mmol) of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) was mixed with 100 mL of NMP at room temperature until completely dissolved; then, the reaction solution was detected by a thermometer, and after the system temperature reached -5°C, 5.68 g (10 mmol) of the diamine monomer provided in Preparation Example 1 was slowly added under the condition of maintaining an inert gas atmosphere, and low-temperature stirring was continued for 12 h, and then 1.14 g of the end-capping agent phthalic anhydride was added for further reaction for 2 h to obtain a polyamic acid solution. The molar ratio of the diamine to the dianhydride was 1:1 by calculation.

[0207] (2) 0.8 mL (10 mmol) of pyridine was added to the polyamic acid solution obtained in step (1), and then 1.88 mL (20 mmol) of acetic anhydride was slowly added at a rate of 1.5 mL / min, and after the addition was completed, the solution was heated to 85°C and stirred for 16 h, and the color of the solution changed from transparent to light yellow. The light yellow solution was added to 250 mL of rapidly stirred ethanol solvent, and light yellow precipitates were immediately precipitated. Light yellow resin powder was obtained by vacuum suction filtration, and the light yellow powder was washed with ethanol, suction filtered, and dried to obtain a self-repairing thermoplastic polyimide resin. The molar ratio of pyridine to acetic anhydride was 1:2 by calculation; the molar ratio of acetic anhydride to diamine monomer was 2:1.

[0208] Example 4

[0209] This example provides a self-repairing thermoplastic polyimide resin, and the molecular structural formula thereof is:

[0210]

[0211] The specific synthesis steps are as follows:

[0212] (1) 3.54 g (11 mmol) of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) was mixed with 100 mL of NMP at room temperature until completely dissolved; then, the reaction solution was detected by a thermometer, and after the system temperature reached -5°C, 5.68 g (10 mmol) of the diamine monomer provided in Preparation Example 1 was slowly added under the condition of maintaining an inert gas atmosphere, and low-temperature stirring was continued for 12 h, and then 1.14 g of the end-capping agent phthalic anhydride was added for further reaction for 2 h to obtain a polyamic acid solution. The molar ratio of the diamine to the dianhydride was 1:1 by calculation.

[0213] (2) To the polyamic acid solution prepared in step (1), 0.8 mL (10 mmol) of pyridine was added, and then 1.88 mL (20 mmol) of acetic anhydride was slowly added at a rate of 1.5 mL / min. After the addition was completed, the solution was stirred at 85 °C for 16 h, and the color of the solution changed from transparent to light yellow. The light yellow solution was added to 250 mL of rapidly stirred ethanol solvent, and light yellow precipitates were immediately separated out. The light yellow resin powder was obtained by vacuum filtration, and then the light yellow powder was washed, filtered and dried using ethanol to obtain a thermoplastic polyimide resin. The molar ratio of pyridine to acetic anhydride was 1:2, and the molar ratio of acetic anhydride to diamine monomer was 2:1.

[0214] Comparative Example 1

[0215] The comparative example 1 provides a thermoplastic polyimide, and the molecular structure formula is as follows:

[0216]

[0217] The preparation method of the thermoplastic polyimide resin in the comparative example is as follows:

[0218] (1) 2.398 g (11 mmol) of pyromellitic dianhydride was mixed with 100 mL of NMP at room temperature until completely dissolved; then the reaction solution was cooled and replaced with argon, and the temperature of the system was detected by a thermometer. When the temperature reached -5 °C, 2.92 g (10 mmol) of 1,3-bis(4'-aminophenoxy) benzene (CAS No.: 2479-46-1) was slowly added under the condition of maintaining an inert gas atmosphere. After continuing to stir at low temperature for 12 h, 1.14 g of end-capping agent phthalic anhydride was added and reacted for 2 h to obtain a polyamic acid solution. The molar ratio of 1,3-bis(4'-aminophenoxy) benzene to pyromellitic dianhydride was 1:1.

[0219] (2) To the polyamic acid solution prepared in step (1), 0.8 mL (10 mmol) of pyridine was added, and then 1.88 mL (20 mmol) of acetic anhydride was slowly added at a rate of 1.5 mL / min. After the addition was completed, the solution was stirred at 85 °C for 16 h, and the color of the solution changed from transparent to light yellow. The light yellow solution was added to 250 mL of rapidly stirred ethanol solvent, and light yellow precipitates were immediately separated out. The light yellow resin powder was obtained by vacuum filtration, and then the light yellow powder was washed, filtered and dried using ethanol to obtain a thermoplastic polyimide resin. The molar ratio of pyridine to acetic anhydride was 1:2, and the molar ratio of acetic anhydride to diamine monomer was 2:1.

[0220] Comparative Example 2

[0221] Comparative Example 2 provides a thermoplastic polyimide, the molecular structure of which is as follows:

[0222]

[0223] The synthesis method of the thermoplastic polyimide resin of this structure is as follows:

[0224] (1) 3.54 g (11 mmol) of 3,3',4,4'-benzophenonetetracarboxylic dianhydride was mixed with 100 mL of NMP at room temperature until completely dissolved; then, cooling was performed and argon replacement was performed, the reaction solution was detected by a thermometer, after the system temperature reached -5℃, 2.92 g (10 mmol) of 1,3-bis(4'-aminophenoxy)benzene (CAS No.: 2479-46-1) was slowly added under the condition of maintaining an inert gas atmosphere, after 12 h of low-temperature stirring, 1.14 g of the end-capping agent phthalic anhydride was added and the reaction was continued for 2 h to obtain a polyamic acid solution. The molar ratio of 1,3-bis(4'-aminophenoxy)benzene to 3,3',4,4'-benzophenonetetracarboxylic dianhydride was 1:1 by calculation.

[0225] (2) 0.8 mL (10 mmol) of pyridine was added to the polyamic acid solution prepared in step (1), and 1.88 mL (20 mmol) of dehydrating agent acetic anhydride was slowly added at a speed of 1.5 mL / min. After the addition was completed, the temperature was raised to 85℃ and stirring was performed for 16 h, and the solution turned from transparent to light yellow. The light yellow solution obtained was added to 250 mL of rapidly stirred ethanol solvent, and light yellow precipitate was immediately precipitated. Light yellow resin powder was obtained by vacuum suction filtration, and finally the light yellow powder was washed, suction filtered and dried with ethanol to obtain a self-repairing thermoplastic polyimide resin. The molar ratio of pyridine to acetic anhydride was 1:2; the molar ratio of acetic anhydride to diamine monomer was 2:1 by calculation.

[0226] Experimental data

[0227] Self-repairing performance test method: the thermoplastic polyimide resin film obtained in Examples 1-4 was cut with a blade, heated at 60℃, placed under an optical microscope, and the healing state of the scratch of the sample at different heating times was tracked.

[0228] From Figures 1-4 it can be seen that the thermoplastic polyimide resin obtained in Examples 1-4 has achieved a certain degree of healing of the blade scratch at 60℃ for 3 h, and the blade scratch of the film of each example has been basically repaired when the time is extended to 12 h, it can be seen that the thermoplastic polyimide resin film prepared by the present application has good self-repairing performance. Referring to Figure 4 and Figure 5It can be seen that the ordinary polyimide material in Comparative Examples 1-2 does not complete the repair of the shear trace after being heated at the same temperature for the same time as Examples 1-4, and does not have a self-repairing function.

[0229] Mechanical properties: the tensile strength and elongation at break of the polyimide resin materials prepared in Examples 1-4 and Comparative Examples 1-2 were tested according to standard GB / T1040.2-2022, and the bending strength was tested according to standard GB / T9341-2008. The test results are shown in Table 1 below.

[0230] Table 1 Mechanical properties of polyimide resin

[0231]

[0232] From Table 1 above, it can be seen that the polyimide resin prepared by the present application has excellent self-repairing performance and good mechanical properties.

[0233] Although the preferred embodiments of the present application have been disclosed as above, they are not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application by using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, which does not deviate from the technical solutions of the present application, shall fall within the protection scope of the present application.

Claims

1. A diamine monomer characterized in that, has a molecular formula as shown in formula I: Formula I In the formula, Y is one of NH or O atom, and m is an arbitrary integer between 1 and 5.

2. A method of preparing a diamine monomer as claimed in claim 1, characterized in that, The method comprises the following steps: S1: adding raw material 1, p-aminophenol and alkaline compound into a polar solvent, heating and stirring, filtering to obtain a solid after the reaction is completed, and washing and drying to obtain intermediate 1; The raw material 1 is any one of 2,6-dichlorobenzoic acid and 2,6-difluorobenzoic acid; S2: dissolving intermediate 1, raw material 2 and organic base into dichloromethane, slowly adding a condensing agent solution into the dichloromethane solution, stirring until the reaction is completed, diluting with ethyl acetate, then sequentially washing the diluted solution with hydrochloric acid solution, saturated brine and saturated sodium bicarbonate solution, filtering the obtained solution with a drying agent, and then rotary evaporating to obtain intermediate 2; The raw material 2 has a molecular formula as shown in formula II: Formula II In the formula, Y is one of NH or O atom, and m is an arbitrary integer between 1 and 5. S3: dissolving intermediate 2, thioctic acid and organic base into dichloromethane, slowly adding a condensing agent solution into the dichloromethane solution, stirring until the reaction is completed, diluting with ethyl acetate, then sequentially washing the diluted solution with hydrochloric acid solution, saturated brine and saturated sodium bicarbonate solution, filtering the obtained solution with a drying agent, and then rotary evaporating to obtain the diamine monomer.

3. The preparation method according to claim 2, characterized in that, In step S1, the alkaline compound 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; The molar ratio of the raw material 1 to p-aminophenol is 1:(1-5); The molar ratio of the raw material 1 to the alkaline compound is 1:(1-5).

4. The preparation method according to claim 2, characterized in that, In steps S2 and S3, the organic base is any one of pyridine, 2,6-dimethylpyridine, 2,6-di-tert-butylpyridine, 2,4,6-trimethylpyridine, 4-dimethylaminopyridine and 4-pyrrolidinopyridine; The condensing agent is any one of N,N'-diisopropylcarbodiimide, dicyclohexylcarbodiimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride; The solvent of the condensing agent solution is any one of DMF, DCM, DMAc and NMP.

5. The preparation method according to claim 2, characterized in that, In step S2: The molar ratio of intermediate 1 to raw material 2 is 1:(1-5); The molar ratio of intermediate 1 to organic base is 1:(1-5); The molar ratio of intermediate 1 to condensing agent is 1:(1-5).

6. The preparation method according to claim 2, characterized in that, In step S3: The molar ratio of thioctic acid to intermediate 2 is 1:(1-5); The molar ratio of thioctic acid to organic base is 1:(1-5); The molar ratio of thioctic acid to condensing agent is 1:(1-5).

7. A method for producing a self-repairing thermoplastic polyimide resin, characterized by, The method comprises the following steps: (1) mixing a dianhydride monomer and a polar solvent at room temperature until the dianhydride monomer is completely dissolved, then performing cooling and inert gas replacement, and adding a diamine monomer to stir at low temperature to obtain a polyamic acid solution; (2) adding an organic base into the polyamide acid solution prepared in step (1), then adding a dehydrating agent dropwise, stirring after temperature rising after the dropwise addition is completed, adding the obtained solution into an alcohol solvent after the reaction is completed, and precipitating a precipitate; obtaining a resin powder through reduced pressure suction filtration, and washing, suction filtration and drying the resin powder using an alcohol solvent, thereby preparing a self-repairing thermoplastic polyimide resin; In step (1), the diamine monomer is the diamine monomer according to claim 1 or the diamine monomer prepared by the preparation method according to any one of claims 2-6. In step (1), the dianhydride monomer has any one of the structures shown in the following formulae A1-A9: 。 8. The preparation method according to claim 7, characterized in that, In step (1), the molar ratio of the diamine monomer to the dianhydride monomer is 1:(1.05-2).

9. The preparation method according to claim 7, characterized in that, In step (2), 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, 4-dimethylaminopyridine, and 1,8-diazabicyclo[5.4.0]undec-7-ene. The dehydrating agent is any one or more of acetic anhydride, propionic anhydride, acetyl chloride, dicyclohexylcarbodiimide, trifluoroacetic anhydride, and thionyl chloride. The molar ratio of the organic base to the dehydrating agent is 1:(1-4). The molar ratio of the dehydrating agent to the diamine monomer is (1-8):

1.

10. A self-repairing thermoplastic polyimide resin prepared by the method of any one of claims 7 to 9, characterized in that, has a molecular structural formula as shown in formula III: Formula III In the formula, Y is one of NH or O atom, m is any integer between 1 and 5, n≥5, and x≥5. In the formula, the Ar part has any one of the structures shown in the following formulae: 。

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