A diamine monomer containing a flexible fatty chain and its preparation method and application

Abstract

The present invention belongs to the technical field of polyimide materials, specifically relating to a diamine monomer containing a flexible fatty chain, its preparation method, and its application. The diamine monomer prepared by the present invention increases the flexibility of the molecular chain by introducing an alkyl chain into the molecule, and ensures good interchain stacking by introducing aromatic units at both ends of the alkyl chain. The resulting polyimide exhibits the advantages of low dielectric constant, low dielectric loss, and high dimensional stability. Furthermore, the preparation method is simple to operate, facilitating commercial applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyimide materials and more specifically relates to a diamine monomer containing a flexible fatty chain and a preparation method and application thereof. Background Art

[0002] The arrival of fifth-generation mobile communication technology (5G) has driven the development of many industrial chains and provided development opportunities for corresponding materials. Among them, modified polyimide (MPI) is one of the key dielectric materials in the 5G communication field. It is a new type of 5G antenna material obtained by modifying traditional polyimide (PI). In addition to its advantages such as excellent mechanical properties, high electrical and chemical stability, and high temperature resistance, it also has the advantages of simple production process and low cost. However, the dielectric constant and dielectric loss of existing MPI materials are high, which cannot meet the development requirements of the 5G communication field.

[0003] At present, the above problems are often solved by modifying the monomers of MPI to improve the hydrophobicity of MPI, reduce the molar polarizability, and reduce the dielectric constant of the polymer. However, while the existing technology modifies MPI and reduces the dielectric constant of the polymer, there are problems such as loose stacking between molecules. Although loose stacking between molecules can reduce the dielectric constant of the polymer to a certain extent, it will also reduce the dimensional stability of the polymer. For example, Popovici et al. disclosed a cyclohexanediamine monomer, and the polymer prepared from the cyclohexanediamine monomer can reduce the dielectric constant of the polymer to a certain extent (Dumitru Popovici, Camelia Hulubei, Vasile Cozan, Gabriela Lisa, Maria Bruma, Polyimides containing cycloaliphatic segments for low dielectric material, High Performance Polymers, 2012, 24 (3): 194-199.), which is 3.14-2.83@10 6 Hz, but the stacking tightness between its molecules is extremely poor, which makes the polymer have poor dimensional stability, which is not conducive to its application in the field of 5G communications. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of the existing MPI molecules, such as poor stacking compactness and poor dimensional stability, and to provide a diamine monomer containing a flexible fatty chain, which can be used to prepare MPI with good stacking compactness, good dimensional stability, low dielectric constant and low dielectric loss.

[0005] The purpose of the present invention is to provide a method for preparing a diamine monomer containing a flexible fatty chain.

[0006] Another object of the present invention is to provide an application of a diamine monomer containing a flexible fatty chain in the preparation of a polyimide material.

[0007] Another object of the present invention is to provide a polyimide material prepared from diamine monomers containing flexible fatty chains.

[0008] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0009] A diamine monomer containing a flexible fatty chain, the structural formula of which is shown in formula (I) or formula (II):

[0010]

[0011] Wherein, R1 and R2 are each independently selected from substituted or unsubstituted aromatic rings, substituted or unsubstituted aromatic heterocycles, and the substituents of the substituted aromatic rings or substituted aromatic heterocycles are H, F, C 1～5 One or more of alkoxy groups;

[0012] R3 is an aromatic amine group; 1≦n≦18.

[0013] Preferably, R1 and R2 are each independently selected from substituted or unsubstituted benzene ring, substituted or unsubstituted naphthalene ring, substituted or unsubstituted anthracene ring, substituted or unsubstituted carbazole, wherein the substituent is H, F, C 1～3 One or more of alkoxy groups; R3 is aniline or aminopyridine; 1≦n≦10.

[0014] Preferably, R1 and R2 are each independently selected from

[0015] One of

[0016] Wherein, R3 is an aniline group or an aminopyridine group; R 4～13 Each independently selected from H, F, C 1～3 One of the alkoxy groups; 4≦n≦8.

[0017] The diamine monomer of the present invention introduces an alkyl chain into the main chain, thereby weakening the interaction force between molecular chains and increasing the free volume. The introduction of the non-polar alkyl chain can effectively reduce the number of polarized molecules per unit volume and improve the hydrophobicity of the polymer, thereby reducing the dielectric constant and dielectric loss of the obtained polyimide. At the same time, by appropriately destroying the rigid structure of the main chain (i.e., introducing the alkyl chain to increase the flexibility of the molecular chain), combined with the π-π stacking effect of the aromatic units at both ends of the alkyl chain to ensure good stacking between the molecular chains, the polyimide has good dimensional stability.

[0018] The present invention also provides a method for preparing a diamine monomer containing a flexible fatty chain, comprising the following steps:

[0019] S1. Dissolve X-R1 in an organic solvent, adjust the pH to alkaline, react for 30 to 60 minutes, and then add After the reaction is complete, the compound represented by formula (III) or formula (IV) is obtained by post-treatment;

[0020]

[0021] S2. X-R2 is dissolved in an organic solvent, the pH is adjusted to alkaline, and the reaction is continued for 30 to 60 minutes. The compound of formula (III) obtained in step S1 is added and the reaction is completed. The compound is then post-treated to obtain a compound of formula (V);

[0022]

[0023] S3. The catalyst, and (the compound of formula (IV) obtained in step S1 or the compound of formula (V) obtained in step S2) are dissolved in an organic solvent, and then a carbonate aqueous solution is added and heated in an inert gas atmosphere to complete the reaction, and then post-treated to obtain the product;

[0024] Wherein, X is a halogen; and the definitions of R1, R2, R3, and n are consistent with those above.

[0025] Preferably, in steps S1 and S2, the pH is adjusted to alkaline using sodium hydroxide, potassium hydroxide or potassium carbonate.

[0026] Preferably, in step S1, the reaction temperature is 25-80°C.

[0027] Preferably, in step S2, the reaction temperature is 25-80°C.

[0028] Preferably, in step S3, the catalyst is a palladium catalyst;

[0029] Preferably, in step S3, the temperature of the heating reaction is 80-100°C.

[0030] Preferably, in step S3, the heating reaction time is 12 to 36 hours.

[0031] Preferably, in step S3, the inert gas is nitrogen or argon.

[0032] Preferably, in step S3, the carbonate aqueous solution is a sodium carbonate aqueous solution or a potassium carbonate aqueous solution.

[0033] Preferably, in steps S1, S2, and S3, the organic solvent is one or more of N,N-dimethylformamide, toluene, and ethanol.

[0034] The present invention also protects the use of a diamine monomer containing a flexible fatty chain in the preparation of a polyimide material.

[0035] The present invention also protects a polyimide material prepared from a diamine monomer containing a flexible fatty chain.

[0036] The present invention has the following beneficial effects:

[0037] The diamine monomer prepared by the present invention increases the flexibility of the molecular chain by introducing an alkyl chain into the molecule, and ensures good stacking between the molecular chains by introducing aromatic units at both ends of the alkyl chain, so that the polyimide prepared therefrom not only has the properties of low dielectric constant, low dielectric loss, and high dimensional stability; moreover, the preparation method of the diamine monomer of the present invention is simple, suitable for large-scale industrial production, and conducive to commercial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the NMR spectrum of the DiCzDA diamine monomer prepared in Example 5 of the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the accompanying drawings and specific examples, but the examples do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0040] Unless otherwise specified, all reagents and materials used in the following examples were commercially available.

[0041] Example 1 Preparation of Flexible Fatty Chain Diamine Monomer (DiPhDA)

[0042]

[0043] S1. Dissolve p-bromophenol (10 g, 58.16 mmol) and potassium hydroxide (7.69 g, 139.58 mmol) in ethanol (150 mL). Heat to 80°C and reflux with stirring for 1 hour. Then add 1,4-dibromobutane (2.9 mL, 24.23 mmol) and continue to reflux and stir at 80°C until the reaction is complete. Remove ethanol by distillation under reduced pressure, and extract with a mixed solution of distilled water and dichloromethane in a volume ratio of 1:1. The organic layer is dried over anhydrous magnesium sulfate and filtered. Remove the solvent by distillation under reduced pressure and separate by column chromatography. The eluent is a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:0 to 0:1 to obtain the initial product a with a yield of 45% (4.34 g).

[0044]

[0045] S2. Tetrakis(triphenylphosphine)palladium (300 mg, 0.26 mmol), initial product a (4 g, 10.05 mmol), and 3-aminophenylboronic acid (3.58 g, 26.13 mmol) were added to a mixture of sodium carbonate aqueous solution (2M, 26 mL, 52 mmol), toluene (90 mL), and ethanol (20 mL). The mixture was stirred at 90°C overnight under a nitrogen atmosphere, cooled to room temperature, and extracted with a mixed solution of distilled water and dichloromethane in a volume ratio of 1:1. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was removed by distillation under reduced pressure and then separated by column chromatography. The eluent was a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:0 to 0:1 to obtain a diamine monomer (DiPhDA) with a yield of about 53% (2.26 g).

[0046]

[0047] The NMR data are: 1 H NMR (300MHz, DMSO, ppm): δ1.99 (m, 4H), 4.41 (m, 4H), 5.09 (s, 4H), 6.56 (d, 2H, J= 7.9Hz), 6.89 (s, 2H), 6.97 (m, 6H), 7.32 (t, 2H, J = 7.2Hz), 7.83 (d, 4H, J = 8.5Hz).

[0048] Example 2 Preparation of Flexible Fatty Chain Diamine Monomer (PhCzDA)

[0049]

[0050] S1. 3-Bromocarbazole (10 g, 40.82 mmol) and sodium hydroxide (2.45 g, 61.23 mmol) were dissolved in N,N-dimethylformamide (20 mL) solution and stirred at room temperature for 30 minutes. 1,4-Dibromobutane (14.7 mL, 122.46 mmol) was added and the reaction was continued until the reaction was complete. The mixture was extracted with a mixed solution of distilled water and dichloromethane in a volume ratio of 1:1. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was removed by distillation under reduced pressure. The intermediate a was purified by column chromatography (eluent: a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:0 to 0:1) and recrystallization to obtain the intermediate a with a yield of about 69% (10.67 g).

[0051]

[0052] S2. Dissolve p-bromophenol (3.18 g, 18.47 mmol) and potassium carbonate (10.2 g, 73.88 mmol) in N,N-dimethylformamide (50 mL) solution, heat and stir at 80°C for 1 hour, add intermediate a (10.5 g, 27.71 mmol), continue heating and reflux with stirring until the reaction is complete, extract with a mixed solution of distilled water and dichloromethane in a volume ratio of 1:1, take the organic layer, dry it with anhydrous magnesium sulfate, filter it, remove the solvent by distillation under reduced pressure, and separate it by column chromatography. The eluent is a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:0 to 0:1 to obtain the initial product b with a yield of about 30% (2.69 g).

[0053]

[0054] S3. Tetrakis(triphenylphosphine)palladium (161 mg, 0.14 mmol), initial product b (2.6 g, 5.37 mmol), and 3-aminophenylboronic acid (1.91 g, 13.96 mmol) were dissolved in a mixture of sodium carbonate aqueous solution (2M, 14 mL, 28 mmol), toluene (80 mL), and ethanol (10 mL). The mixture was stirred at 90°C overnight under a nitrogen atmosphere, cooled to room temperature, and extracted with a mixed solution of distilled water and dichloromethane in a volume ratio of 1:1. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was removed by distillation under reduced pressure and then separated by column chromatography. The eluent was a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:0 to 0:1 to obtain a diamine monomer (PhCzDA) with a yield of about 42% (1.12 g).

[0055]

[0056] The NMR data are: 1 H NMR (300MHz, DMSO, ppm): δ1.89(m,4H),4.38(m,4H),5.10(s,4H),6.55(d,2H,J=7.9Hz),6.89–6.99(m,6H),7.11(t,1H,J=7.7H z),7.18(t,2H,J=7.4Hz),7.41–7.53(m,4H),7.57(d,1H,J=7.7Hz),7.62(d,1H,J=8.6Hz),8.20(d,1H,J=7.7Hz),8.32(s,1H).

[0057] Example 3 Preparation of Flexible Fatty Chain Diamine Monomer (DiOcCzDA)

[0058]

[0059] S1. 3-Bromocarbazole (11.2 g, 45.72 mmol) and sodium hydroxide (5.49 g, 137.16 mmol) were dissolved in N,N-dimethylformamide (60 mL) solution and stirred at room temperature for 30 minutes. 1,8-Dibromooctane (3.5 mL, 19.05 mmol) was added to complete the reaction. The mixture was extracted with a mixed solution of distilled water and dichloromethane in a volume ratio of 1:1. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was removed by distillation under reduced pressure. The product c was purified by column chromatography (eluent: a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:0 to 0:1) and recrystallization. The yield was about 49% (5.6 g).

[0060]

[0061] S2. Tetrakis(triphenylphosphine)palladium (277 mg, 0.24 mmol), initial product c (5.6 g, 9.33 mmol), and 3-aminophenylboronic acid (3.33 g, 24.26 mmol) were dissolved in a mixture of sodium carbonate aqueous solution (2M, 24 mL, 48 mmol), toluene (100 mL), and ethanol (20 mL). The mixture was stirred at 90°C overnight under a nitrogen atmosphere, cooled to room temperature, and extracted with a mixed solution of distilled water and dichloromethane in a volume ratio of 1:1. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was removed by distillation under reduced pressure and then separated by column chromatography. The eluent was a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:0 to 0:1 to obtain a diamine monomer (DiOcCzDA) with a yield of about 44% (2.57 g).

[0062]

[0063] The NMR data are: 1 H NMR (300MHz, DMSO, ppm): δ1.42(m,8H),1.87(m,4H),4.37(m,4H),5.12(s,4H),6.55(d,2H,J=7.9Hz),6.89(d,2H,J=7.7Hz),6.94(s,2H),7.1 1(t,2H,J=7.7Hz),7.18(t,2H,J=7.4Hz),7.41(t,2H,J=7.2Hz),7.53–7.57(m,4H),7.62(d,2H,J=8.6Hz),8.20(d,2H,J=7.7Hz),8.32(s,2H).

[0064] Example 4 Preparation of Flexible Fatty Chain Diamine Monomer (DiHeCzDA)

[0065]

[0066] S1. 3-Bromocarbazole (10.7 g, 43.368 mmol) and sodium hydroxide (5.2 g, 131.04 mmol) were dissolved in a solution of N,N-dimethylformamide (60 mL), stirred at room temperature for 30 minutes, and 1,6-dibromohexane (2.92 mL, 18.2 mmol) was added to complete the reaction. The mixture was extracted with a mixed solution of distilled water and dichloromethane in a volume ratio of 1:1. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was removed by distillation under reduced pressure, and the initial product d was purified by column chromatography (a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:0 to 0:1) and recrystallization. The yield was about 53% (5.5 g).

[0067]

[0068] S2. Tetrakis(triphenylphosphine)palladium (289 mg, 0.25 mmol), initial product d (5.5 g, 9.61 mmol), and 3-aminophenylboronic acid (3.43 g, 25 mmol) were dissolved in a mixture of aqueous sodium carbonate solution (2 M, 25 mL, 50 mmol), toluene (110 mL), and ethanol (20 mL). The mixture was stirred at 90°C overnight under a nitrogen atmosphere, cooled to room temperature, and extracted with a mixed solution of distilled water and dichloromethane in a volume ratio of 1:1. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was removed by distillation under reduced pressure and then separated by column chromatography. The eluent was a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:0 to 0:1 to obtain a diamine monomer (DiHeCzDA) with a yield of about 41% (2.36 g).

[0069]

[0070] The NMR data are: 1 H NMR (300MHz, DMSO, ppm): δ1.43(m,4H),1.87(m,4H),4.38(m,4H),5.12(s,4H),6.56(d,2H,J=7.9Hz),6.89(d,2H,J=7.7Hz),6.94(s,2H),7.1 1(t,2H,J=7.7Hz),7.18(t,2H,J=7.4Hz),7.41(t,2H,J=7.2Hz),7.53–7.57(m,4H),7.62(d,2H,J=8.6Hz),8.20(d,2H,J=7.7Hz),8.32(s,2H).

[0071] Example 5 Preparation of Flexible Fatty Chain Diamine Monomer (DiBuCzDA)

[0072]

[0073] S1. 3-Bromocarbazole (11.6 g, 47.35 mmol) and sodium hydroxide (5.68 g, 142.05 mmol) were dissolved in N,N-dimethylformamide (60 mL) solution and stirred at room temperature for 30 minutes. 1,4-Dibromobutane (2.33 mL, 19.73 mmol) was added to complete the reaction. The mixture was extracted with a mixed solution of distilled water and dichloromethane in a volume ratio of 1:1. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was removed by distillation under reduced pressure. The initial product e was purified by column chromatography (eluent: a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:0 to 0:1) and recrystallization. The yield was about 52% (5.6 g).

[0074]

[0075] S2. Tetrakis(triphenylphosphine)palladium (308 mg, 0.267 mmol), initial product e (5.59 g, 10.27 mmol), and 3-aminophenylboronic acid (3.66 g, 26.69 mmol) were dissolved in a mixture of aqueous sodium carbonate solution (2M, 27 mL, 54 mmol), toluene (120 mL), and ethanol (20 mL). The mixture was stirred at 90°C overnight under a nitrogen atmosphere, cooled to room temperature, and extracted with a mixed solution of distilled water and dichloromethane in a volume ratio of 1:1. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was removed by distillation under reduced pressure and then separated by column chromatography. The eluent was a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 1:0 to 0:1 to obtain a diamine monomer (DiBuCzDA) with a yield of about 43% (2.5 g).

[0076]

[0077] The NMR data are: 1 H NMR (400 MHz, DMSO, ppm): δ1.89 (m, 4H), 4.39 (m, 4H), 5.12 (s, 4H), 6.56 (dd, 2H, J1 = 7.88 Hz, J2 = 1.4 Hz), 6.90 (d, 2H, J = 7.72 Hz), 6.95 (s, 2H), 7.12 (t, 2H, J = 7.72 Hz), 7.19 (t, 2H, J = 7.36 Hz), 7.42 (t, 2H, J = 7.2 Hz), 7.54–7.58 (m, 4H), 7.63 (dd, 2H, J1 = 8.56 Hz, J2 = 1.64 Hz), 8.21 (d, 2H, J = 7.68 Hz), 8.33 (s, 2H) (the spectrum is shown in FIG. Figure 1 shown).

[0078] Mass spectral data: HRMS (ESI) m / z: (M+H) + calcd.for C40 H 35 N4,571.2856; found,571.2845.Elemental Analysis,Calcd for C 37 H 26 N2:C,84.18;H,6.00;N,9.82.Found:C,84.082;H,5.671;N,9.655.

[0079] Experimental Example 1

[0080] The present invention uses the diamine monomer prepared in Example 5 as an example for performance testing. The monomer structures prepared in other examples are similar to those in Example 5, that is, the central core all uses a non-polar alkyl chain with aromatic units introduced at both ends, and thus have similar effects to Example 5.

[0081] The diamine monomer DiBuCzDA (3.7 mmol) and hexafluorodianhydride (6FDA) (3.7 mmol) in Example 5 were dissolved in 20 mL of N,N-dimethylacetamide solvent (hexafluorodianhydride was added in batches), and the reaction was completed by stirring at room temperature under a nitrogen atmosphere to obtain a polyamic acid (PAA) solution. The PAA solution was then coated into a film, and then subjected to gradient imidization at 100°C, 200°C, 300°C, and 350°C to obtain a polyimide film.

[0082] The resulting polyimide film had an average thickness of 37 μm, a dielectric constant of 3.35, and a dielectric loss of 0.012 at a frequency of 10 GHz (measured using a vector network analyzer). This demonstrates that the monomers described in the present invention are advantageous for obtaining polyimide with a low dielectric constant and low dielectric loss.

[0083] The coefficient of thermal expansion (CTE) is 61.02 μm / (m·°C), which proves that the obtained polyimide film has good dimensional stability.

[0084] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A diamine monomer containing a flexible fatty chain, characterized in that: The structural formula is shown in formula (II): Wherein, the R1 is selected from R2 is independently selected from One of the following; Among them, R 4～ R 13 is H; R3 is aminophenyl or aminopyridyl; 4≦n≦8.

2. The method for preparing the diamine monomer according to claim 1, wherein The diamine monomer is Its preparation comprises the following steps: S1. dissolving 3-bromocarbazole in an organic solvent, adjusting the pH to alkaline, reacting for 30 to 60 minutes, adding 1,4-dibromobutane to complete the reaction, and post-treating to obtain the compound represented by formula (III); S2. dissolving p-bromophenol in an organic solvent, adjusting the pH to alkaline, reacting for 30 to 60 minutes, adding the compound of formula (III) obtained in step S1, and reacting completely, followed by post-treatment to obtain a compound represented by formula (V); S3. The catalyst, 3-aminophenylboronic acid and the compound of formula (V) obtained in step S2 are dissolved in an organic solvent, and then a carbonate aqueous solution is added and heated in an inert gas atmosphere to complete the reaction, and then post-treated to obtain the product.

3. The method for preparing the diamine monomer according to claim 1, characterized in that: The diamine monomer is Its preparation comprises the following steps: S1. dissolving 3-bromocarbazole in an organic solvent, adjusting the pH to alkaline, reacting for 30 to 60 minutes, adding 1,8-dibromooctane to complete the reaction, and post-treating to obtain the compound represented by formula (III); Formula (III); S2. The catalyst, 3-aminophenylboronic acid and the compound of formula (III) obtained in step S1 are dissolved in an organic solvent, and then a carbonate aqueous solution is added and heated in an inert gas atmosphere to complete the reaction, and then post-treated to obtain the product.

4. The method for preparing the diamine monomer according to claim 1, characterized in that: The diamine monomer is Its preparation comprises the following steps: S1. dissolving 3-bromocarbazole in an organic solvent, adjusting the pH to alkaline, reacting for 30 to 60 minutes, adding 1,6-dibromohexane to complete the reaction, and post-processing to obtain the compound represented by formula (III); S2. The catalyst, 3-aminophenylboronic acid and the compound of formula (III) obtained in step S1 are dissolved in an organic solvent, and then a carbonate aqueous solution is added and heated in an inert gas atmosphere to complete the reaction, and then post-treated to obtain the product.

5. The method for preparing the diamine monomer according to claim 1, characterized in that: The diamine monomer is Its preparation comprises the following steps: S1. dissolving 3-bromocarbazole in an organic solvent, adjusting the pH to alkaline, reacting for 30 to 60 minutes, adding 1,4-dibromobutane to complete the reaction, and post-treating to obtain the compound represented by formula (III); S2. The catalyst, 3-aminophenylboronic acid and the compound of formula (III) obtained in step S1 are dissolved in an organic solvent, and then a carbonate aqueous solution is added and heated in an inert gas atmosphere to complete the reaction, and then post-treated to obtain the product.

6. The preparation method according to any one of claims 2 to 5, characterized in that: In step S3 of claim 2 or step S2 of claims 3 to 5, the catalyst is a palladium catalyst.

7. The preparation method according to any one of claims 2 to 5, characterized in that: In step S3 of claim 2 or step S2 of claims 3 to 5, the temperature of the heating reaction is 80 to 100°C.

8. The preparation method according to any one of claims 2 to 5, characterized in that: In step S3 of claim 2 or step S2 of claims 3 to 5, the heating reaction time is 12 to 36 hours.

9. The preparation method according to any one of claims 2 to 5, characterized in that: In step S3 of claim 2 or step S2 of claims 3 to 5, the carbonate aqueous solution is a sodium carbonate aqueous solution or a potassium carbonate aqueous solution.

10. Use of the diamine monomer according to claim 1 in the preparation of polyimide materials.

11. A polyimide material prepared from the diamine monomer according to claim 1.

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