Cationic modified polyimide resin and preparation method thereof

Abstract

The invention discloses cation modified polyimide resin and a preparation method thereof, and the preparation method comprises the following steps: S1, mixing a dianhydride monomer with a polar solvent, adding a cation diamine monomer, and stirring to obtain a polyamide acid solution; and S2, adding an organic alkali and a dehydrating agent into the polyamide acid solution, heating, stirring, adding the reaction solution into an alcohol solvent to separate out a precipitate, collecting the precipitate, washing, and drying to obtain the cation modified polyimide resin, the side chain of which contains an imidazole cation modified group, and the cation modified polyimide resin has good hydrophilic performance and mechanical property.

Description

Technical Field

[0001] The invention relates to the technical field of polyimide materials, and in particular to a cation-modified polyimide resin and a preparation method thereof. Background Art

[0002] Polyimide has excellent thermal stability, good mechanical properties and excellent chemical properties, and is widely used in interventional medical devices, aerospace, microelectronics and other fields. Medical catheters are the core components of minimally invasive medical devices. However, in actual use, due to the poor water wettability of ordinary polyimide, the surface friction and adhesion of medical catheters are large, which can easily damage epithelial tissues such as the urethra and blood vessel walls when inserted into the human body, causing pain or burning sensations. In addition, it is easy for bacteria to adhere and thrombosis to form, increasing the risk of infection.

[0003] At present, the common technical means to improve the hydrophilicity of polyimide medical catheters is to use plasma technology or surface coating to modify the surface of polyimide medical catheters to be hydrophilic. However, the post-treatment method requires the addition of additional processing steps, which makes the process complicated. On the other hand, the peeling or shedding of the coating will not only lead to a decrease in hydrophilicity, but also increase the risk of use for medical catheters. Summary of the invention

[0004] In order to overcome the above disadvantages, the present invention also provides a cationic modified polyimide resin, the side chain of which contains an imidazole cationic modified group, has good hydrophilic properties, and does not lose the mechanical properties of the resin. The resin has the following structural formula:

[0005]

[0006] wherein Ar is selected from an aromatic structure;

[0007] n≥5; 0≤a≤6; 1≤b≤3;

[0008] X is selected from any one of F, Cl, Br, and I;

[0009] R is an alkyl group;

[0010] Y is selected from imidazole compounds.

[0011] Preferably, n≥50, more preferably, n≥100.

[0012] Furthermore, Y is selected from any one of the following structures:

[0013]

[0014] Further, Ar is selected from any one of the following structures:

[0015]

[0016] The raw materials for preparing the above-mentioned cation-modified polyimide resin include cationic diamine monomers, and the structural formula thereof is as follows:

[0017]

[0018] Wherein, 0≤a≤6; 1≤b≤3; X is selected from any one of F, Cl, Br, and I; R is an alkyl group; and Y is selected from imidazole compounds.

[0019] The synthetic route of cationic diamine monomer is as follows:

[0020]

[0021] Among them: 0≤a≤6, 1≤b≤3, illustratively, a is 0, 1, 2, 3, 4, 5, 6, and b is 1, 2, 3.

[0022] X is selected from any one of F, Cl, Br, and I, R is an alkyl group, and Y is selected from imidazole compounds;

[0023] The specific synthesis steps of the above cationic diamine monomer are:

[0024] Step 1, adding raw material 1, raw material 2, and an acid catalyst to toluene or xylene, heating and stirring to react, and after the reaction is completed, obtaining intermediate 1 by recrystallization;

[0025] Step 2, adding intermediate 1 and YR into an organic solvent, heating and refluxing, and after the reaction is completed, purifying to obtain intermediate 2;

[0026] Step 3: adding intermediate 2, p-aminophenol and a base to a polar solvent, heating and stirring, and after the reaction is completed, purifying to obtain a cationic diamine monomer.

[0027] Preferably, the synthesis steps of the cationic diamine monomer are:

[0028] Step 1, adding raw material 1, raw material 2, and an acid catalyst to toluene or xylene, stirring at 110-160° C. for 2-24 hours, and using a water separator to separate water. After the reaction is completed, intermediate 1 is obtained by recrystallization;

[0029] Step 2, adding intermediate 1 and YR to an organic solvent, reflux at 60-120°C for 2-24h, after the reaction is completed, extract with ethyl acetate and water, combine the organic phases, dry, filter, and rotary evaporate to obtain intermediate 2;

[0030] Step 3: add intermediate 2, p-aminophenol and base to a polar solvent, stir at 80-150° C. for 2-24 hours, and after the reaction is completed, pour the reaction solution into water, filter, wash and dry to obtain a cationic diamine monomer.

[0031] Furthermore, in step 1, raw material 1 is any one of 2,6-dichlorobenzoic acid and 2,6-difluorobenzoic acid.

[0032] Furthermore, in step 1, raw material 2 is any one of bromoethanol, tribromoethanol, bromopropanol, bromobutanol and bromopentanol.

[0033] Furthermore, in step 1, the molar ratio of raw material 1 to raw material 2 is 1:0.5-4.

[0034] Preferably, in step 1, the molar ratio of raw material 1 to raw material 2 is 1:1-3.

[0035] Furthermore, in step 1, the acid catalyst is selected from any one or more of sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid.

[0036] Furthermore, in step 1, the molar ratio of raw material 1 to acid catalyst is 1:0.05-0.3.

[0037] Preferably, in step 1, the molar ratio of raw material 1 to acid catalyst is 1:0.1-0.2.

[0038] Furthermore, in step 2, the synthesis method of YR is as follows: after YH, RX and an organic solvent are uniformly mixed, the mixture is heated to reflux; after the reaction is completed, the raw material YR is purified;

[0039] Further, RX is selected from any halogenated alkane, and X is selected from any one of F, Cl, Br, and I;

[0040] Further, YH is selected from any one of the following structures:

[0041]

[0042]

[0043] Furthermore, in step 2, the molar ratio of intermediate 1 to YR is 1:1-5.

[0044] Furthermore, in step 2, the organic solvent is selected from any one or more of acetonitrile, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, methyl tert-butyl ether, and toluene.

[0045] In some embodiments, in step 2, the molar concentration of the organic solvent relative to the intermediate 1 can be any value between 0.01M and 1M.

[0046] Furthermore, in step 3, the base is selected from any one or more 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.

[0047] Furthermore, in step 3, the polar solvent is selected from any one or more of DMF, DMAc, and NMP.

[0048] Furthermore, in step 3, the molar ratio of intermediate 2 to p-aminophenol is 1:1-5.

[0049] Illustratively, the molar ratio of intermediate 2 to p-aminophenol is 1:1, 1:2, 1:3, 1:4, 1:5 or a range consisting of any two thereof.

[0050] Furthermore, in step 3, the molar ratio of the intermediate 2 to the base is 1:1-5.

[0051] Illustratively, the molar ratio of intermediate 2 to the base is 1:1, 1:2, 1:3, 1:4, 1:5 or a range consisting of any two thereof.

[0052] Furthermore, in step 3, the concentration of intermediate 2 in the polar solvent is 0.1M to 1M (M represents mol / L).

[0053] Furthermore, the raw materials for preparing the above-mentioned cationic modified polyimide resin also include a dianhydride monomer, and the dianhydride monomer is any one of the following structures:

[0054]

[0055] The preparation method of the above-mentioned cationic modified polyimide resin comprises the following steps:

[0056] S1, mixing the dianhydride monomer and the polar solvent, adding the cationic diamine monomer, stirring, and obtaining a polyamic acid solution;

[0057] S2. Adding an organic base and a dehydrating agent to the polyamic acid solution, heating and stirring, adding the reaction solution to an alcohol solvent to precipitate a precipitate, collecting the precipitate, washing and drying, and obtaining a cationic modified polyimide resin.

[0058] Preferably, the preparation method of the above-mentioned cationic modified polyimide resin comprises the following steps:

[0059] S1. At room temperature, the dianhydride monomer and the polar solvent are mixed until completely dissolved, and then the temperature is lowered and replaced with an inert gas. After the system reaches a set temperature, a cationic diamine monomer is added under an inert gas atmosphere, and stirring is continued at ≤5°C for 2-24h to obtain a polyamic acid solution;

[0060] S2. Add an organic base to the polyamic acid solution, slowly drop a dehydrating agent, stir at 80-180°C for 2-24 hours, slowly drop the reaction solution into an alcohol solvent to precipitate a precipitate, and filter under reduced pressure to obtain a resin powder. Wash the powder with an alcohol solvent, filter, and dry it to obtain a cationic modified polyimide resin.

[0061] Furthermore, in step S1, the molar ratio of the cationic diamine monomer to the dianhydride monomer is 1:1.05 to 1:2.

[0062] Illustratively, the molar ratio of the cationic diamine monomer to the dianhydride monomer is 1:1.05, 1:1.10, 1:1.15, 1:2, or a range consisting of any two thereof.

[0063] Furthermore, in step S1, the polar solvent is selected from any one or more of DMF, DMAc, NMP, and DMSO.

[0064] Furthermore, in step S1, the amount of polar solvent used is calculated based on the amount of monomers used so that the solid content of the system is between 10 and 20 wt%.

[0065] Furthermore, in step S1, the inert gas is selected from any one of nitrogen or argon.

[0066] Furthermore, in step S1, the solid content of the polyamic acid is ≥5%.

[0067] Further, in step S2, the organic base is selected from any one or more of triethylamine, ethylenediamine, diisopropylethylamine, diethylamine, pyridine, 2,6-lutidine, 2,4,6-trimethylpyridine, 2,6-di-tert-butylpyridine, 4-dimethylaminopyridine, and 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0068] Furthermore, in step S2, the dehydrating agent is selected from any one or more of acetic anhydride, propionic anhydride, acetyl chloride, dicyclohexylcarbocyanine, trifluoroacetic anhydride, and thionyl chloride.

[0069] Furthermore, in step S2, the molar ratio of the organic base to the dehydrating agent is 1:1-2.

[0070] Furthermore, in step S2, the molar ratio of the dehydrating agent to the cationic diamine monomer is 2 to 8:1.

[0071] Furthermore, in step S2, the alcohol solvent is selected from one or more of methanol, ethanol, propanol, isopropanol, hexafluoroisopropanol, butanol, tert-butanol, and acetone.

[0072] Furthermore, in step S2, the amount of the alcohol solvent used is 5-50 times the volume of the reaction solution.

[0073] The beneficial effects of the present invention are:

[0074] (1) The polyimide resin prepared by the present invention using cationic diamine monomers contains imidazolium cationic modification groups on the side chains, which improves the hydrophilicity of the resin while ensuring its mechanical properties. After being prepared into products such as medical catheters, no hydrophilic post-treatment is required, thereby simplifying the preparation process of medical catheters and saving resources.

[0075] (2) The hydrophilic groups of the present application are grafted onto the side chains of polyimide, which will not cause the risk of peeling or falling off like the hydrophilic coating obtained by post-treatment, thereby reducing the risk of use and being able to exert the hydrophilic effect more lastingly. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0077] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0078] Figure 1 This is a test diagram of the water contact angle of the resin prepared in Example 1 of the present invention;

[0079] Figure 2 This is a test diagram of the water contact angle of the resin prepared in Example 2 of the present invention;

[0080] Figure 3 This is a water contact angle test diagram of the resin prepared in Example 3 of the present invention;

[0081] Figure 4 This is a water contact angle test diagram of the resin prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0082] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0083] Except as shown in the operating examples or otherwise indicated, all numbers used in the specification and claims to indicate the amount of ingredients, physicochemical properties, etc. are understood to be adjusted by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters listed in the above specification and the attached claims are approximate values, and those skilled in the art can use the teachings disclosed herein to seek to obtain the desired properties and appropriately change these approximate values. The use of numerical ranges expressed as endpoints includes all numbers within the range and any range within the range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4 and 5, etc.

[0084] Imidazole is the most common main structure of ionic liquids, and has been verified for a long time in terms of material stability, hydrophilicity, and environmental protection. The applicant has found that the introduction of imidazole structure into polyester can effectively improve hydrophilicity without losing its mechanical properties. The details are as follows:

[0085] A cationic modified polyimide resin has the following structural formula:

[0086]

[0087] wherein Ar is selected from an aromatic structure;

[0088] n≥5; 0≤a≤6; 1≤b≤3;

[0089] X is selected from any one of F, Cl, Br, and I;

[0090] R is an alkyl group;

[0091] Y is selected from imidazole compounds.

[0092] In some embodiments, n≥50.

[0093] In some embodiments, n≥100.

[0094] In some embodiments, Y is selected from any one of the following structures:

[0095]

[0096] In some embodiments, Ar is selected from any one of the following structures:

[0097]

[0098] In some embodiments, the raw materials for preparing the above-mentioned cationic modified polyimide resin further include a dianhydride monomer, and the dianhydride monomer is any one of the following structures:

[0099]

[0100] The preparation method of the above-mentioned cationic modified polyimide resin comprises the following steps:

[0101] S1. At room temperature, mix the dianhydride monomer and the polar solvent until they are completely dissolved; then cool down and replace with inert gas, wait for the system to stabilize and reach the set low temperature environment, add the cationic diamine monomer under the inert gas atmosphere, continue stirring at low temperature for 2 to 24 hours, and obtain a polyamic acid solution.

[0102] S2, adding an organic base to the polyamic acid solution obtained in step S1, and slowly dripping a dehydrating agent. Then, heating to 80-180°C and stirring for 2-24 hours, slowly dripping the reaction solution into an alcohol solvent, precipitating a precipitate, and filtering under reduced pressure to obtain a resin powder, and then washing the powder with an alcohol solvent, filtering, and drying to obtain a cationic modified polyimide resin.

[0103] In some embodiments, in step S1, the molar ratio of the cationic diamine monomer to the dianhydride monomer is 1:1.05 to 1:2.

[0104] In some embodiments, in step S1, the polar solvent is selected from any one or more of DMF, DMAc, NMP, and DMSO.

[0105] Furthermore, in step S1, the amount of polar solvent used is calculated based on the amount of monomers used so that the solid content of the system is between 10 and 20 wt%.

[0106] In some embodiments, in step S1, the inert gas is selected from argon or nitrogen.

[0107] In some embodiments, in step S1, the low temperature environment is ≤5°C.

[0108] In some embodiments, in step S1, the solid content of the polyamic acid solution is ≥5%.

[0109] In some embodiments, in step S2, the organic base is selected from any one or more of triethylamine, ethylenediamine, diisopropylethylamine, diethylamine, pyridine, 2,6-lutidine, 2,4,6-trimethylpyridine, 2,6-di-tert-butylpyridine, 4-dimethylaminopyridine, and 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0110] In some embodiments, in step S2, the dehydrating agent is selected from any one or more of acetic anhydride, propionic anhydride, acetyl chloride, dicyclohexylcarbocyanine, trifluoroacetic anhydride and thionyl chloride.

[0111] In some embodiments, in step S2, the molar ratio of the organic base to the dehydrating agent is 1:1-2.

[0112] In some embodiments, in step S2, the molar ratio of the dehydrating agent to the diamine monomer is 2 to 8:1.

[0113] In some embodiments, in step S2, the alcohol solvent is selected from one or more of methanol, ethanol, propanol, isopropanol, hexafluoroisopropanol, butanol, tert-butanol, and acetone.

[0114] In some embodiments, in step S2, the amount of alcohol solvent used is 5 to 50 times the volume of the reaction solution.

[0115] The raw materials for preparing the above-mentioned cation-modified polyimide resin involve a cationic diamine monomer, and the structural formula of the cationic diamine monomer is:

[0116]

[0117] Wherein, 0≤a≤6; 1≤b≤3; X is selected from any one of F, Cl, Br, and I; R is an alkyl group; and Y is selected from imidazole compounds.

[0118] In some embodiments, the synthesis route of the cationic diamine monomer is as follows:

[0119]

[0120] Wherein: 0≤a≤6, 1≤b≤3, X is selected from any one of F, Cl, Br, I, R is an alkyl group, and Y is selected from imidazole compounds;

[0121] The specific synthesis steps of the cationic diamine monomer are:

[0122] Step 1: Add raw material 1, raw material 2, and an acid catalyst to toluene or xylene, stir at 110-160° C. for 2-24 hours, and use a water separator to separate water. After the reaction is completed, obtain intermediate 1 by recrystallization;

[0123] Step 2: Add intermediate 1 and YR to an organic solvent, reflux at 60-120°C for 2-24 hours. After the reaction is completed, extract with ethyl acetate and water, combine the organic phases, dry, filter, and rotary evaporate to obtain intermediate 2;

[0124] Step 3: Add intermediate 2, p-aminophenol and base to a polar solvent, stir at 80-150° C. for 2-24 hours. After the reaction is completed, pour the reaction solution into water, filter, wash and dry to obtain a cationic diamine monomer.

[0125] In some embodiments, in step 1, raw material 1 is any one of 2,6-dichlorobenzoic acid and 2,6-difluorobenzoic acid.

[0126] In some embodiments, in step 1, raw material 2 is any one of bromoethanol, tribromoethanol, bromopropanol, bromobutanol and bromopentanol.

[0127] In some embodiments, in step 1, the molar ratio of raw material 1 to raw material 2 is 1:0.5-4.

[0128] In some embodiments, in step 1, the molar ratio of raw material 1 to raw material 2 is 1:1-3.

[0129] In some embodiments, in step 1, the acid catalyst is selected from any one or more of sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid.

[0130] In some embodiments, in step 1, the molar ratio of raw material 1 to acid catalyst is 1:0.05-0.3.

[0131] In some embodiments, in step 1, the molar ratio of raw material 1 to acid catalyst is 1:0.1-0.2.

[0132] In some embodiments, in step 2, the molar ratio of intermediate 1 to YR is 1:1-5.

[0133] In some embodiments, in step 2, the organic solvent is selected from any one or more of acetonitrile, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, methyl tert-butyl ether, and toluene.

[0134] In some embodiments, in step 2, the molar concentration of the intermediate 1 in the organic solvent can be any value between 0.01M and 1M.

[0135] In some embodiments, in step 2, the desiccant is any one of anhydrous sodium sulfate and anhydrous magnesium sulfate.

[0136] In some embodiments, in step 2, the synthesis method of YR is as follows: after YH, RX and an organic solvent are uniformly mixed, the mixture is heated to reflux; after the reaction is completed, the raw material YR is obtained by post-treatment and purification;

[0137] In some embodiments, RX is selected from any halogenated alkane, and X is selected from any one of F, Cl, Br, and I.

[0138] In some embodiments, YH is selected from any one of the following structures:

[0139]

[0140] In some embodiments, in step 3, the base is selected from any one or more 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.

[0141] In some embodiments, in step 3, the polar solvent is selected from any one or more of DMF, DMAc, and NMP.

[0142] In some embodiments, in step 3, the molar ratio of intermediate 2 to p-aminophenol is 1:1-5.

[0143] In some embodiments, in step 3, the molar ratio of intermediate 2 to base is 1:1-5.

[0144] Example

[0145] The following examples describe the disclosure of the present invention in more detail, and these examples are intended for illustrative purposes only, as various modifications and variations within the scope of the disclosure of the present invention will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0146] The CAS numbers of the key raw materials used in the preparation examples, embodiments and comparative examples are shown in Table 1.

[0147] Table 1

[0148] Compound CAS Number 2,6-Dichlorobenzoic acid 50-30-6 p-Aminophenol 123-30-8 1,3-Bis(4'-aminophenoxy)benzene 2479-46-1 N-Methylimidazole 616-47-7 N-Methylbenzimidazole 1632-83-3

[0149] Preparation Example 1

[0150] This example prepares a 1,3-diaryl ether diamine modified with an N-methylimidazolium cation, and the specific structural formula is as follows:

[0151]

[0152] The synthetic route of the diamine monomer is as follows:

[0153]

[0154] Specific synthesis steps:

[0155] Step 1: 2,6-dichlorobenzoic acid (raw material 1, 1.91 g, 10 mmol), bromoethanol (raw material 2, 1.5 g, 12 mmol), and methanesulfonic acid (0.096 g, 1 mmol) were added to 100 mL of toluene, refluxed and stirred at 115°C, and water was separated using a water separator. After reacting for 12 hours, toluene was removed by rotary evaporation, and intermediate 1 was obtained by recrystallization. It was calculated that the molar ratio of 2,6-dichlorobenzoic acid to bromoethanol was 1:1.2; the molar ratio of 2,6-dichlorobenzoic acid to methanesulfonic acid was 1:0.1.

[0156] Step 2: Add intermediate 1 (3.0 g, 10 mmol) and N-methylimidazole (0.984 g, 12 mmol) to 100 mL of acetonitrile, mix well, and reflux for 12 h; after the reaction, extract with ethyl acetate and water, combine the organic phases, dry with anhydrous sodium sulfate, filter, and remove acetonitrile with a rotary evaporator to obtain intermediate 2. The molar ratio of intermediate 1 to N-methylimidazole is calculated to be 1:1.2.

[0157] Step 3: Add intermediate 2 (3.8 g, 10 mmol), p-aminophenol (1.31 g, 12 mmol), and NaOH (1.2 g, 30 mmol) to 100 mL of NMP, and stir at 120° C. for 12 h. After the reaction is completed, filter the reaction solution through diatomaceous earth and silica gel, pour it into a large amount of water, filter to obtain a solid, and after washing and drying, obtain a cationic diamine monomer 1. It is calculated that the molar ratio of intermediate 2 to p-aminophenol is 1:1.2; the molar ratio of intermediate 2 to the base is 1:3.

[0158] NMR data of cationic diamine monomer 1: 1 H NMR(500MHz,Chloroform-d)δ7.60(t,J=7.5Hz,1H),7.10(d,J=7.5Hz,2H),6.63–6.52(m,8H),6.33(s,1H ), 6.30 (d, J = 7.5Hz, 1H), 6.02 (d, J = 7.5Hz, 1H), 5.49 (t, J = 4.6Hz, 2H), 4.99 (t, J = 4.6Hz, 2H), 3.16 (s, 3H).

[0159] Preparation Example 2

[0160] This example prepares a 1,3-diaryl ether diamine modified with an N-methylbenzimidazole cation, and the specific structural formula is as follows:

[0161]

[0162] The synthetic route of the diamine monomer is as follows:

[0163]

[0164] Specific synthesis steps:

[0165] Step 1: 2,6-dichlorobenzoic acid (1.91 g, 10 mmol), bromoethanol (1.5 g, 12 mmol), and methanesulfonic acid (0.096 g, 1 mmol) were added to 100 mL of toluene, refluxed and stirred at 115°C, and water was separated using a water separator. After reacting for 12 hours, toluene was removed by rotary evaporation, and intermediate 1 was obtained by recrystallization. It was calculated that the molar ratio of 2,6-dichlorobenzoic acid to bromoethanol was 1:1.2; the molar ratio of 2,6-dichlorobenzoic acid to methanesulfonic acid was 1:0.1.

[0166] Step 2: Add intermediate 1 (3.0 g, 10 mmol) and N-methylbenzimidazole (1.58 g, 12 mmol) to 100 mL of acetonitrile, mix well, and reflux for 12 h; after the reaction, extract with ethyl acetate and water, combine the organic phases, dry with anhydrous sodium sulfate, filter, and remove acetonitrile with a rotary evaporator to obtain intermediate 2. The molar ratio of intermediate 1 to N-methylbenzimidazole is calculated to be 1:1.2.

[0167] Step 3: Add intermediate 2 (4.3 g, 10 mmol), p-aminophenol (1.31 g, 12 mmol), and NaOH (1.2 g, 30 mmol) to 100 mL of NMP, and stir at 120°C for 12 h. After the reaction is completed, filter the reaction solution through diatomaceous earth and silica gel, pour it into a large amount of water, filter the solid, wash and dry it, and obtain the cationic diamine monomer 2. It is calculated that the molar ratio of intermediate 2 to p-aminophenol is 1:1.2; the molar ratio of intermediate 2 to the base is 1:3.

[0168] Preparation Example 3

[0169] This example prepares a 1,3-diaryl ether diamine modified with a tri-N-methylimidazolium cation, and the specific structural formula is as follows:

[0170]

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

[0172]

[0173] Step 1: 2,6-dichlorobenzoic acid (1.91 g, 10 mmol), tribromoethanol (3.4 g, 12 mmol), and methanesulfonic acid (0.096 g, 1 mmol) were added to 100 mL of toluene, refluxed at 115°C with stirring and separated by a water separator, reacted for 12 hours, and toluene was removed by rotary evaporation, and intermediate 1 was obtained by recrystallization. It was calculated that the molar ratio of 2,6-dichlorobenzoic acid to tribromoethanol was 1:1.2; the molar ratio of 2,6-dichlorobenzoic acid to methanesulfonic acid was 1:0.1.

[0174] Step 2: Add intermediate 1 (4.56 g, 10 mmol) and N-methylimidazole (2.95 g, 36 mmol) to 100 mL of acetonitrile, mix well, and reflux for 12 h; after the reaction, extract with ethyl acetate and water, combine the organic phases, dry with anhydrous sodium sulfate, filter, and remove acetonitrile with a rotary evaporator to obtain intermediate 2. The molar ratio of intermediate 1 to N-methylimidazole is calculated to be 1:3.6.

[0175] Step 3: Add intermediate 2 (7.02 g, 10 mmol), p-aminophenol (1.31 g, 12 mmol), and NaOH (1.2 g, 30 mmol) to 100 mL NMP, and stir at 120° C. for 12 h. After the reaction is completed, filter the reaction solution through diatomaceous earth and silica gel, pour it into a large amount of water, filter the solid, and wash and dry it to obtain cationic diamine monomer 3. It is calculated that the molar ratio of intermediate 2 to p-aminophenol is 1:1.2; the molar ratio of intermediate 2 to base is 1:3.

[0176] Example 1

[0177] This example prepares a polyimide modified with N-methylimidazole cation, and the specific structural formula is as follows:

[0178]

[0179] The synthesis method of the polyimide resin of this structure is as follows:

[0180] S1: Under room temperature, completely dissolve pyromellitic anhydride (2.398 g, 11 mmol) in N-methylpyrrolidone NMP (100 ml); then cool down and replace with argon, detect the reaction solution with a thermometer, wait for the system temperature to drop to -5 ° C, and slowly add the cationic diamine monomer 1 (10 mmol, 5.25 g) synthesized in Preparation Example 1 under the condition of maintaining an inert gas atmosphere, stir at low temperature for 12 hours, add phthalic anhydride as a capping agent, and continue to react for 2 hours to obtain a polyamic acid solution. It is calculated that the molar ratio of pyromellitic anhydride to cationic diamine monomer 1 is 1:1.1.

[0181] S2: Add pyridine (0.8mL, 10mmol) to the polyamic acid solution obtained in S1, and slowly drip the dehydrating agent acetic anhydride (1.88mL, 20mmol). After the addition is completed, heat to 150℃ and stir for 16h, and the solution turns from transparent to light yellow. After the reaction is completed, slowly drip the obtained light yellow solution into the rapidly stirred ethanol, and a light yellow precipitate will precipitate immediately. The light yellow resin powder is obtained by vacuum filtration, and finally the light yellow powder is washed, filtered and dried with ethanol to obtain a cationic modified polyimide resin. It is calculated that the molar ratio of pyridine to acetic anhydride is 1:2; the molar ratio of acetic anhydride to cationic diamine monomer is 2:1.

[0182] NMR data: 1 H NMR(500MHz,Chloroform-d)δ8.44(s,2H),8.20–8.10(m,2H),7.46(t,J=2.0Hz,1H),7.37(t,J=2.0Hz,1H),7.18–7.06(m,3H),7 .07–6.99(m,2H),6.91–6.81(m,2H),6.39(s,1H),6.37–6.22(m,2H),5.49(t,J=4.1Hz,2H),4.99(t,J=4.1Hz,2H),3.05(s,3H).

[0183] Example 2

[0184] This example prepares a polyimide modified with N-methylbenzimidazole cation, and the specific structural formula is as follows:

[0185]

[0186] The synthesis method of the polyimide resin of this structure is as follows:

[0187] S1: Under room temperature, completely dissolve pyromellitic anhydride (2.398 g, 11 mmol) in N-methylpyrrolidone (100 ml); then cool down and replace with argon, detect the reaction solution with a thermometer, wait for the system temperature to reach -5°C, and slowly add the cationic diamine monomer 2 (5.75 g, 10 mmol) synthesized in Preparation Example 2 under the condition of maintaining an inert gas atmosphere, continue stirring at low temperature for 12 hours, add phthalic anhydride as a capping agent, and continue to react for 2 hours to obtain a polyamic acid solution. It is calculated that the molar ratio of pyromellitic anhydride to cationic diamine monomer 2 is 1:1.1.

[0188] S2: Add pyridine (0.8mL, 10mmol) to the polyamic acid solution obtained in S1, and slowly drip the dehydrating agent acetic anhydride (1.88mL, 20mmol). After the addition is completed, heat to 150℃ and stir for 16h, and the solution turns from transparent to light yellow. After the reaction is completed, slowly drip the obtained light yellow solution into the rapidly stirred ethanol, and a light yellow precipitate will precipitate immediately. The light yellow resin powder is obtained by vacuum filtration, and finally the light yellow powder is washed, filtered and dried with ethanol to obtain a cationic modified polyimide resin. It is calculated that the molar ratio of pyridine to acetic anhydride is 1:2; the molar ratio of acetic anhydride to cationic diamine monomer 2 is 2:1.

[0189] Example 3

[0190] This example prepares a tri-N-methylimidazolium cation-modified polyimide, the specific structural formula of which is as follows:

[0191]

[0192] The synthesis method of the polyimide resin of this structure is as follows:

[0193] S1: Under room temperature, completely dissolve pyromellitic anhydride (2.398 g, 11 mmol) in N-methylpyrrolidone (100 ml), then cool down and replace with argon, detect the reaction solution with a thermometer, wait until the system temperature reaches -5°C, and slowly add the cationic diamine monomer 3 (8.47 g, 10 mmol) prepared in Preparation Example 3 under the condition of maintaining an inert gas atmosphere, continue stirring at low temperature for 12 hours, add phthalic anhydride as a capping agent, and continue to react for 2 hours to obtain a polyamic acid solution. It is calculated that the molar ratio of pyromellitic anhydride to cationic diamine monomer 3 is 1:1.1.

[0194] S2: Add pyridine (0.8mL, 10mmol) to the polyamic acid solution obtained in S1, and slowly drop the dehydrating agent acetic anhydride (1.88mL, 20mmol). After the addition is completed, heat to 150℃ and stir for 16h, and the solution turns from transparent to light yellow. After the reaction is completed, slowly drop the obtained light yellow solution into the rapidly stirred ethanol, and a light yellow precipitate will immediately precipitate. The light yellow resin powder is obtained by vacuum filtration, and finally the light yellow powder is continued to be washed, filtered and dried with ethanol to obtain a cationic modified polyimide resin. It is calculated that the molar ratio of pyridine to acetic anhydride is 1:2; the molar ratio of acetic anhydride to cationic diamine monomer 3 is 2:1.

[0195] Comparative Example 1

[0196] In this comparative example, the structure of the thermoplastic polyimide is as follows:

[0197]

[0198] The synthesis method of the thermoplastic polyimide resin of this structure is as follows:

[0199] S1: Under room temperature, completely dissolve pyromellitic anhydride (2.398 g, 11 mmol) in N-methylpyrrolidone (100 ml), then cool down and replace with argon, detect the reaction solution with a thermometer, wait for the system temperature to reach -5 ° C, and slowly add 1,3-bis (4'-aminophenoxy) benzene 2.92 g (10 mmol) under the condition of maintaining an inert gas atmosphere, continue to stir at low temperature for 12 hours, add phthalic anhydride as a capping agent, and continue to react for 2 hours to obtain a polyamic acid solution. It is calculated that the molar ratio of pyromellitic anhydride to 1,3-bis (4'-aminophenoxy) benzene is 1:1.1.

[0200] Step 2: Add pyridine (0.8 mL, 10 mmol) to the polyamic acid solution obtained in S1, and slowly drop the dehydrating agent acetic anhydride (1.88 mL, 20 mmol). After the addition is completed, heat to 150 ° C and stir for 16 hours, and the solution turns from transparent to light yellow. After the reaction is completed, slowly drop the obtained light yellow solution into the rapidly stirred ethanol, and a light yellow precipitate will immediately precipitate. The light yellow resin powder is obtained by vacuum filtration, and finally the light yellow powder is continued to be washed, filtered and dried with ethanol to obtain a thermoplastic polyimide resin. It is calculated that the molar ratio of pyridine to acetic anhydride is 1:2; the molar ratio of acetic anhydride to 1,3-bis(4'-aminophenoxy)benzene is 2:1.

[0201] Test Case

[0202] The performance tests were performed on the resins prepared in Examples 1-3 and Comparative Example 1. The test results are shown in Table 1.

[0203] Table 1:

[0204] Test items Example 1 Example 2 Example 3 Comparative Example 1 Water contact angle 45.5° 76.7° 28.3° 93.5° Tensile strength(Mpa) 102 98 95 92 Elongation at break (%) 90 93 92 90 Bending strength(Mpa) 135 132 130 130

[0205] From Table 1 and Figure 1-4 It can be seen from the hydrophilicity test results that the water contact angles of Examples 1-3 are significantly smaller than that of Comparative Example 1, and have excellent hydrophilic effects, and the mechanical properties of Examples 1-3 are not weaker than those of Comparative Example 1. From the above data, it can be seen that the samples of Examples 1-3 provided by the present invention have not only excellent hydrophilicity, but also good material mechanical properties.

[0206] The present invention illustrates the detailed process equipment and process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, change of structural morphology, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0207] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0208] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0209] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

[0210] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A cation-modified polyimide resin, characterized in that: The cationic modified polyimide resin has the following structural formula: wherein Ar is selected from an aromatic structure; n≥5; 0≤a≤6; 1≤b≤3; X is selected from any one of F, Cl, Br, and I; R is an alkyl group; Y is selected from imidazole compounds.

2. The cation-modified polyimide resin according to claim 1, characterized in that: Y is selected from any one of the following structures:

3. The cation-modified polyimide resin according to claim 1, characterized in that: Ar is selected from any one of the following structures:

4. The cation-modified polyimide resin according to claim 1, characterized in that: The raw materials for preparing the cationic modified polyimide resin include cationic diamine monomers, and the structural formula of the cationic diamine monomers is: Wherein, 0≤a≤6; 1≤b≤3; X is selected from any one of F, Cl, Br, and I; R is an alkyl group; and Y is selected from imidazole compounds.

5. The cation-modified polyimide resin according to claim 4, characterized in that: The synthetic route of the cationic diamine monomer is as follows: Wherein: 0≤a≤6, 1≤b≤3, X is selected from any one of F, Cl, Br, I, R is an alkyl group, and Y is selected from imidazole compounds; The synthesis steps of the cationic diamine monomer are: Step 1, adding raw material 1, raw material 2, and an acid catalyst to toluene or xylene, heating and stirring to react, and after the reaction is completed, obtaining intermediate 1 by recrystallization; Step 2, adding intermediate 1 and YR into an organic solvent, heating and refluxing, and after the reaction is completed, purifying to obtain intermediate 2; Step 3: adding intermediate 2, p-aminophenol and a base to a polar solvent, heating and stirring, and after the reaction is completed, purifying to obtain a cationic diamine monomer.

6. The cation-modified polyimide resin according to claim 5, characterized in that: In step 1, the molar ratio of raw material 1 to raw material 2 is 1:0.5-4; In step 1, the raw material 1 is any one of 2,6-dichlorobenzoic acid and 2,6-difluorobenzoic acid; In step 1, the raw material 2 is any one of bromoethanol, tribromoethanol, bromopropanol, bromobutanol and bromopentanol; In step 1, the acid catalyst is selected from any one or more of sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid; In step 1, the molar ratio of the raw material 1 to the acid catalyst is 1:0.05-0.3; In step 2, the molar ratio of the intermediate 1 to YR is 1:1-5; In step 2, the organic solvent is selected from any one or more of acetonitrile, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, methyl tert-butyl ether, and toluene; In step 3, the base is selected from any one or more 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; In step 3, the polar solvent is selected from any one or more of DMF, DMAc, and NMP; In step 3, the molar ratio of intermediate 2 to p-aminophenol is 1:1-5; In step 3, the molar ratio of intermediate 2 to base is 1:1-5.

7. The cation-modified polyimide resin according to claim 5, characterized in that: The synthesis method of YR is as follows: after YH, RX and an organic solvent are uniformly mixed, the mixture is heated to reflux; after the reaction is completed, the raw material YR is obtained by post-processing and purification; The RX is selected from any halogenated alkane, and X is selected from any one of F, Cl, Br, and I; The YH is selected from any one of the following structures:

8. The cation-modified polyimide resin according to claim 1, characterized in that: The raw materials for preparing the cationic modified polyimide resin include dianhydride monomers, and the dianhydride monomers are any one of the following structures:

9. The method for preparing a cation-modified polyimide resin according to any one of claims 1 to 8, characterized in that: The steps include: S1, mixing the dianhydride monomer and the polar solvent, adding the cationic diamine monomer, stirring, and obtaining a polyamic acid solution; S2. Adding an organic base and a dehydrating agent to the polyamic acid solution, heating and stirring, adding the reaction solution to an alcohol solvent to precipitate a precipitate, collecting the precipitate, washing and drying, and obtaining a cationic modified polyimide resin.

10. The method for preparing a cation-modified polyimide resin according to claim 9, characterized in that: In step S1, the molar ratio of the cationic diamine monomer to the dianhydride monomer is 1:1.05 to 1:2; In step S1, the polar solvent is selected from any one or more of DMF, DMAc, NMP, and DMSO; In step S1, the organic base is selected from any one or more of triethylamine, ethylenediamine, diisopropylethylamine, diethylamine, pyridine, 2,6-lutidine, 2,4,6-trimethylpyridine, 2,6-di-tert-butylpyridine, 4-dimethylaminopyridine, and 1,8-diazabicyclo[5.4.0]undec-7-ene; In step S2, the dehydrating agent is selected from any one or more of acetic anhydride, propionic anhydride, acetyl chloride, dicyclohexylcarbocyanine, trifluoroacetic anhydride, and thionyl chloride; In step S2, the molar ratio of the organic base to the dehydrating agent is 1:1-2; In step S2, the molar ratio of the dehydrating agent to the cationic diamine monomer is 2 to 8:1; In step S2, the alcohol solvent is selected from one or more of methanol, ethanol, propanol, isopropanol, hexafluoroisopropanol, butanol, tert-butanol, and acetone.

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