Aromatic diamine monomer, polyimide and preparation method and application thereof

Abstract

The invention provides an aromatic diamine monomer, polyimide and a preparation method and application thereof, and relates to the technical field of preparation of aromatic diamine monomers and high-performance polymers of the aromatic diamine monomers, adamantyl, pyridine heterocyclic rings and flexible ether bonds are introduced into the aromatic diamine monomer, and when the aromatic diamine monomer is used for preparing the polyimide, the aromatic diamine monomer can be used for preparing the polyimide. The polyimide not only has higher solubility and glass transition temperature in a specific solvent, but also has excellent optical performance and lower dielectric constant, and can be used for preparing polyimide films and electronic packaging materials.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of aromatic diamine monomers and their high-performance polymers, and particularly relates to an aromatic diamine monomer, a polyimide, and their preparation methods and applications. Background Art

[0002] With the increasing demand for high-performance materials in the development of science and technology, special engineering plastics have emerged as the times require. Among them, common commercial special plastics mainly include polyimide (PI), polyether ether ketone, polyether sulfone, and polyphenylene sulfide, etc. These materials have the properties of high temperature resistance, high strength, high modulus, corrosion resistance, wear resistance, and light weight. The molecular chain of polyimide contains a large number of aromatic rings and heterocycles, which endows it with excellent heat stability. Therefore, it is the special engineering plastic with the highest heat resistance grade. Compared with polyimide, materials such as PEEK and PPS have relatively low glass transition temperatures, generally not exceeding 150 °C, which limits their applications at higher temperatures. However, due to the strong intermolecular interaction of ordinary polyimide, most polyimides are not only insoluble in specific solvents but also have poor melting properties. The disadvantages of insolubility and infusibility of polyimide limit the processing and applications of polyimide in many fields. Traditional polyimides usually have a rigid conjugated aromatic structural backbone and strong intermolecular forces, so they have excellent heat resistance, mechanical properties, and dielectric properties. However, traditional polyimides usually have a relatively deep color due to electron conjugation and the formation of intermolecular and intramolecular charge transfer complexes (CTC), which hinders their application as optical films. On the other hand, the extensive charge transfer effect in PI will lead to poor dielectric and dielectric loss performance of PI at high frequencies. For example, the commercial Kapton film has poor processing performance, low transparency, and high dielectric constant, which limits its application range. Therefore, it is of great significance to design polyimides with high solubility, optical transparency, and low dielectric constant. Summary of the Invention

[0003] The present invention aims to provide an aromatic diamine monomer, a polyimide, and their preparation methods and applications.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides an aromatic diamine monomer, which includes an adamantyl group, a pyridine heterocycle, and a flexible ether bond. The structural formula of the aromatic diamine monomer is shown as follows:

[0006]

[0007] Among them, R is one of -H, C1-6 alkyl, halogenated C1-6 alkyl, -F, -Cl, and -Br, preferably -CH3 or -CF3.

[0008] The present invention also provides a method for preparing the aromatic diamine monomer as described above, comprising the following steps:

[0009] S1: Under a protective atmosphere, add 1,3-adamantanediol and phenol into a reaction vessel equipped with mechanical stirring, further add a first catalyst, heat up to 80 - 90 °C and react for 6 - 12 h, then end the reaction. After sedimentation, filtration, drying and recrystallization, 1,3-bis(4-hydroxyphenyl)adamantane can be obtained;

[0010] S2: Mix the 1,3-bis(4-hydroxyphenyl)adamantane, a pyridine source containing nitro group and a base in a first organic solvent, and carry out a substitution reaction at a temperature of 80 - 120 °C for 8 - 12 h to obtain a dinitro compound;

[0011] S3: Mix the dinitro compound, a hydrogenation catalyst, a second organic solvent and a reducing agent, and carry out a catalytic hydrogenation reaction at a temperature of 40 - 100 °C for 8 - 12 h to obtain the aromatic diamine monomer.

[0012] Furthermore, according to the method for preparing the aromatic diamine monomer provided by the present invention, the first catalyst is one of concentrated sulfuric acid, trifluoroacetic acid, methanesulfonic acid and trifluoromethanesulfonic acid, preferably methanesulfonic acid;

[0013] and / or, the pyridine source is one of 2-chloro-5-nitropyridine, 2-chloro-3-methyl-5-nitropyridine, 2-chloro-3-trifluoromethyl-5-nitropyridine, 2-chloro-3-fluoro-5-nitropyridine, 2,3-dichloro-5-nitropyridine and 2-chloro-3-bromo-5-nitropyridine;

[0014] and / or, the base includes at least one of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, sodium bicarbonate and potassium bicarbonate;

[0015] and / or, the first organic solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide;

[0016] and / or, the hydrogenation catalyst includes at least one of palladium-carbon, platinum-carbon, rhodium-carbon and active nickel;

[0017] and / or, the second organic solvent includes at least one of tetrahydrofuran, ethanol, methanol, isopropanol, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, 1,4-dioxane, ethyl acetate, benzene, toluene and xylene;

[0018] and / or, the reducing agent is hydrazine hydrate, and preferably the hydrazine hydrate is added in the form of an aqueous hydrazine hydrate solution.

[0019] Furthermore, according to the preparation method of the aromatic diamine monomer provided by the present invention, the molar ratio of the 1,3-adamantanediol to the phenol is 1:8;

[0020] and / or, the molar ratio of the 1,3-bis(4-hydroxyphenyl)adamantane to the base is 1:1.2 to 3.0;

[0021] and / or, the molar ratio of the 1,3-bis(4-hydroxyphenyl)adamantane to the pyridine source is 1:2 to 2.2;

[0022] The mass ratio of the 1,3-bis(4-hydroxyphenyl)adamantane to the dosage of the first organic solvent is 1 g:9 to 11 mL, preferably 1 g:10 mL;

[0023] and / or, the mass percentage content of the metal element in the palladium-carbon, platinum-carbon and rhodium-carbon is preferably 5 to 10%;

[0024] and / or, the mass of the hydrogenation catalyst is 10 to 15% of the mass of the dinitro compound;

[0025] and / or, the mass concentration of the hydrazine hydrate aqueous solution is 80 to 99%, preferably 98%;

[0026] and / or, the molar ratio of the dinitro compound to the hydrazine hydrate in the hydrazine hydrate aqueous solution is 1:4 to 12, preferably 1:10.

[0027] The present invention also provides a polyimide. The raw materials for synthesizing the polyimide include the aromatic diamine monomer as described above or the aromatic diamine monomer prepared by the preparation method of the aromatic diamine monomer as described above;

[0028] The structural formula of the polyimide is shown as follows:

[0029]

[0030] Among them, R is one of -H, C1-6 alkyl, halogenated C1-6 alkyl, -F, -Cl and -Br, preferably -CH3 or -CF3;

[0031] A is

[0032] Furthermore, according to the polyimide provided by the present invention, the number-average molecular weight of the polyimide is 5.3 - 10.4×10 4 g / mol;

[0033] and / or, the glass transition temperature (Tg) of the polyimide is 222 - 301 °C;

[0034] and / or, the temperature at which 5% of the polyimide undergoes thermal weight loss is 470 - 520 °C;

[0035] and / or, the temperature at which 10% of the polyimide undergoes thermal weight loss is 486 - 550 °C;

[0036] and / or, the dielectric constant of the polyimide at 10 GHz is 2.56 - 3.10;

[0037] and / or, the cut-off wavelength of the polyimide is 343 - 385 nm;

[0038] and / or, the polyimide is soluble in aprotic polar solvents, and the aprotic polar solvents include at least one of N,N-dimethylacetamide, N-methylpyrrolidone, N,N-dimethylformamide, m-cresol, butyrolactone, and sulfolane, preferably including at least one of N,N-dimethylacetamide, N-methylpyrrolidone, N,N-dimethylformamide, and m-cresol.

[0039] The present invention also provides a method for preparing the polyimide as described above, comprising the following steps:

[0040] Thermal imidization method: Under nitrogen protection, add the aromatic diamine monomer and aromatic dianhydride monomer to a third organic solvent, carry out a polycondensation reaction to obtain a polyamic acid solution, and then carry out a dehydration cyclization reaction by gradient heating to synthesize a film-like polyimide;

[0041] Or,

[0042] Chemical imidization method: Under nitrogen protection, add the aromatic diamine monomer and aromatic dianhydride monomer to a third organic solvent, carry out a polycondensation reaction to obtain a polyamic acid solution, then add a dehydrating agent and a catalyst to the polyamic acid solution, stir at 80 - 100 °C for 8 - 12 h, and then pour the obtained mixed solution into ethanol for precipitation, filtration, washing, and drying to obtain a fibrous or flocculent polyimide;

[0043] The temperature of the polycondensation reaction is 23 °C - 28 °C, and the time of the polycondensation reaction is greater than or equal to 24 h;

[0044] and / or, the temperature of the dehydration cyclization of the polyamic acid is 60 - 300 °C;

[0045] and / or, the time of the dehydration cyclization of the polyamic acid is 6 - 12 h, preferably 8 h.

[0046] Furthermore, according to the method for preparing the polyimide provided by the present invention, the aromatic dianhydride monomer is one of diphenyl ether tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, ester bond dianhydride, hexafluorodiacid dianhydride, pyromellitic dianhydride, and bisphenol A dianhydride;

[0047] And / or, the third organic solvent includes at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,4-butyrolactone.

[0048] Further, according to the method for preparing polyimide provided by the present invention, the molar ratio of the aromatic diamine monomer to the dianhydride monomer is 1:1 to 1.3;

[0049] And / or, the molar ratio of the aromatic diamine monomer to the dianhydride monomer is preferably 1:1;

[0050] And / or, the solid content of the mixed solution obtained by mixing the aromatic diamine monomer, the dianhydride monomer, and the third organic solvent is 10-25%.

[0051] The present invention also provides an application of the polyimide as described above or the polyimide prepared by the method for preparing polyimide as described above in the preparation of polyimide film materials or electronic packaging materials.

[0052] An aromatic diamine monomer, a polyimide, and a preparation method and application thereof containing an adamantyl group and a pyridine heterocyclic structure provided by the present invention have the following beneficial effects:

[0053] (1) The aromatic diamine monomer containing an adamantyl group and a pyridine heterocyclic structure prepared by the present invention has cheap and easily available raw materials, a simple synthesis route, the product is easy to recrystallize, purify and separate, the yield is greater than 80%, and it is stable at room temperature.

[0054] (2) The present invention can obtain polyimide films by two cyclization methods, namely chemical imidization method and thermal imidization method. The synthesis and preparation process is simple and easy to industrialize.

[0055] (3) The polyimide prepared by the present invention, including an aromatic diamine monomer containing an adamantyl group, a pyridine heterocyclic ring, and a flexible ether bond, not only has high solubility and high glass transition temperature in a specific solvent, but also has excellent optical properties and low dielectric constant, and can be used in the preparation of polyimide films and electronic packaging materials. Description of the Drawings

[0056] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0057] Figure 1They are the infrared spectra of the intermediate dinitro compound 1,3-bis[4-(2-trifluoromethyl-4-nitropyridyloxy)phenyl]adamantane (AMTFDT) and the aromatic diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane (AMTFDM) in Example 1 provided by the present invention.

[0058] Figure 2 They are the infrared spectra of the polyimides prepared by reacting the aromatic diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane (AMTFDM) with diphenyl ether tetracarboxylic dianhydride (ODPA), benzophenone tetracarboxylic dianhydride (BTDA), biphenyltetracarboxylic dianhydride (α-BPDA), ester bond dianhydride (TAHQ), and bisphenol A dianhydride (BPADA) respectively, provided by the present invention.

[0059] Figure 3 They are the DSC diagrams of the thermal performance curves of the polyimides prepared by reacting the aromatic diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane (AMTFDM) with diphenyl ether tetracarboxylic dianhydride (ODPA), benzophenone tetracarboxylic dianhydride (BTDA), biphenyltetracarboxylic dianhydride (α-BPDA), ester bond dianhydride (TAHQ), hexafluorodiacid dianhydride (6FDA), pyromellitic dianhydride (PMDA), and bisphenol A dianhydride (BPADA) respectively, provided by the present invention.

[0060] Figure 4 They are the TGA diagrams of the thermal performance curves of the polyimides prepared by reacting the aromatic diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane (AMTFDM) with diphenyl ether tetracarboxylic dianhydride (ODPA), benzophenone tetracarboxylic dianhydride (BTDA), biphenyltetracarboxylic dianhydride (α-BPDA), ester bond dianhydride (TAHQ), hexafluorodiacid dianhydride (6FDA), pyromellitic dianhydride (PMDA), and bisphenol A dianhydride (BPADA) respectively, provided by the present invention.

[0061] Figure 5 They are the ultraviolet spectra of the polyimides prepared by reacting the aromatic diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane (AMTFDM) with diphenyl ether tetracarboxylic dianhydride (ODPA), benzophenone tetracarboxylic dianhydride (BTDA), biphenyltetracarboxylic dianhydride (α-BPDA), ester bond dianhydride (TAHQ), hexafluorodiacid dianhydride (6FDA), pyromellitic dianhydride (PMDA), and bisphenol A dianhydride (BPADA) respectively, provided by the present invention. Detailed implementation manners

[0062] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Those skilled in the art should understand that the described embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The process parameters without specific conditions noted in the following embodiments are usually in accordance with conventional conditions.

[0063] In the ranges disclosed in the present invention, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0064] According to the first aspect of the present invention, an aromatic diamine monomer is provided, which includes an adamantyl group, a pyridine heterocycle, and a flexible ether bond. The structural formula of the aromatic diamine monomer is shown as follows:

[0065]

[0066] Wherein, R is one of -H, C1-6 alkyl, halogenated C1-6 alkyl, -F, -Cl, and -Br, preferably -CH3 or -CF3.

[0067] C1-6 alkyl refers to a straight-chain or branched-chain alkyl containing 1-6 carbons, such as methyl, ethyl, propyl, n-butyl, isobutyl, 2,2-dimethylbutane, etc. Halogenated C1-6 alkyl refers to the hydrogen in a straight-chain or branched-chain alkyl containing 1-6 carbons being replaced by a halogen.

[0068] In the aromatic diamine monomer of the present invention, a bulky adamantyl group, a pyridine heterocycle, and a flexible ether bond are introduced. When used to prepare polyimide, the solubility of the polyimide in a specific solvent can be effectively improved. Specifically, the adamantyl group in the aromatic diamine monomer provided by the present invention is an alicyclic structure, which hinders the close packing of the polyimide molecular chains, making it easy for the solvent to diffuse between the chains, thereby increasing the solubility, optical properties, etc. In addition, the presence of the flexible ether group can change the torsion angle of the polyimide molecule, which is beneficial to the rotation of the aromatic ring. At the same time, the solubility of the polyimide prepared therefrom can be further improved by protonation of the lone pair electrons on the nitrogen atom of the pyridine ring. In addition, due to the large volume of the adamantyl group in the aromatic diamine monomer provided by the present invention, the free volume of the polyimide prepared therefrom is increased, and the number of polar groups per unit volume is reduced, thereby reducing the dielectric constant of the polyimide. In addition, due to the excellent heat resistance of adamantane, introducing an adamantane unit into the polyimide can also increase the glass transition temperature of the material.

[0069] According to the second aspect of the present invention, a method for preparing an aromatic diamine monomer is provided, including the following steps:

[0070] S1: Under a protective atmosphere, add 1,3-adamantanediol and phenol into a reaction vessel equipped with mechanical stirring, further add a first catalyst, heat to 80-90 °C and react for 6-12 h, then end the reaction. After sedimentation, filtration, drying, and recrystallization, 1,3-bis(4-hydroxyphenyl)adamantane can be obtained;

[0071] S2: Mix the 1,3-bis(4-hydroxyphenyl)adamantane, a pyridine source containing nitro, and a base in a first organic solvent, and carry out a substitution reaction at a temperature of 80-120 °C for 8-12 h to obtain a dinitro compound;

[0072] S3: Mix the dinitro compound, a hydrogenation catalyst, a second organic solvent, and a reducing agent, and carry out a catalytic hydrogenation reaction at a temperature of 40-100 °C for 8-12 h to obtain the aromatic diamine monomer.

[0073] Specifically, in step S1, the present invention has no special limitation on the protective atmosphere, and conventional protective atmospheres can be used, such as a nitrogen atmosphere or an inert gas atmosphere, etc.

[0074] Specifically, step S2 further includes the following steps:

[0075] When 1,3-bis(4-hydroxyphenyl)adamantane, a pyridine source, a base, and a first organic solvent undergo a substitution reaction at a temperature of 80 to 120 °C, the mixing order of 1,3-bis(4-hydroxyphenyl)adamantane, the pyridine source, the base, and the first organic solvent is not particularly limited and can be any mixing order. After reacting for 8 to 12 h, the reaction solution obtained from the substitution reaction is cooled to room temperature. Further, the reaction solution obtained from the substitution reaction is poured into water, and then solid-liquid separation is carried out. The solid obtained from the solid-liquid separation is washed with water and dried in sequence to obtain a crude dinitro compound; then the crude dinitro compound is recrystallized to obtain a dinitro compound containing an adamantyl group and a pyridine heterocyclic structure;

[0076] Among them, the volume ratio of the first organic solvent to water is preferably 1:2 to 3;

[0077] Furthermore, the above-mentioned recrystallization steps are as follows:

[0078] The crude dinitro compound containing an adamantyl group and a pyridine heterocyclic structure is mixed with N,N-dimethylacetamide, and the temperature is raised to 115 to 125 °C to completely dissolve the crude dinitro compound. Then, it is naturally cooled to 85 to 95 °C to prevent the water added subsequently from being directly lost in the form of water vapor. Then, water is added dropwise until crystals precipitate, and then the addition of water is stopped. After continuing to cool to room temperature and standing for 6 to 12 h, solid-liquid separation is carried out to obtain a recrystallized product. The recrystallized product is washed and dried to obtain a dinitro compound containing an adamantyl group and a pyridine heterocyclic structure;

[0079] The above-mentioned recrystallization is more preferably to mix the crude dinitro compound containing an adamantyl group and a pyridine heterocyclic structure with N,N-dimethylacetamide, raise the temperature to 120 °C, then naturally cool to 90 °C, then add water dropwise until crystals precipitate, and then stop adding water. After continuing to naturally cool to room temperature and standing for 12 h, solid-liquid separation is carried out to obtain a recrystallized product. The recrystallized product is washed and dried to obtain a dinitro compound containing an adamantyl group and a pyridine heterocyclic structure;

[0080] During the above-mentioned recrystallization process, the dosage ratio of the crude dinitro compound containing an adamantyl group and a pyridine heterocyclic structure to N,N-dimethylacetamide is preferably 1 g:9 to 11 mL; the washing liquid for washing is preferably a mixed liquid of N,N-dimethylacetamide and water, and the volume ratio of N,N-dimethylacetamide to water is preferably 4.5 to 5.5:1, more preferably 5:1.

[0081] Specifically, step S3 includes the following steps:

[0082] The preferred mixing sequence of the dinitro compound, hydrogenation catalyst, second organic solvent, and reducing agent is as follows: First, mix the dinitro compound, hydrogenation catalyst, and second organic solvent to obtain a mixed solution; then heat up to the temperature of the catalytic hydrogenation reaction, and then dropwise add the reducing agent to the above-mentioned mixed solution; the dropwise addition is preferably completed within 30 minutes. In the present invention, since a large amount of heat is released and a large number of bubbles are generated during the reduction reaction when the reducing agent is dropwise added, a material that can prevent too-fast dropwise addition needs to be added when hydrazine hydrate is dropwise added.

[0083] Among them, the time of the catalytic hydrogenation reaction refers to the time counted from the completion of the mixing of the dinitro compound, hydrogenation catalyst, second organic solvent, and reducing agent. In the examples provided by the present invention, it is counted from the completion of the addition of the reducing agent.

[0084] After the catalytic hydrogenation reaction is completed, the present invention preferably performs hot solid-liquid separation on the reaction solution obtained from the catalytic hydrogenation reaction (i.e., directly performs solid-liquid separation at the temperature of the catalytic hydrogenation reaction), and then after removing the solvent from the obtained filtrate, mixes it with water for precipitation, and dries the obtained precipitate to obtain an aromatic diamine monomer containing an adamantyl group, a pyridine heterocycle, and a flexible ether bond.

[0085] To avoid the precipitation of the product in the above-mentioned hot solid-liquid separation, the hydrogenation catalyst needs to be removed, and the preferred method for removing the solvent is rotary evaporation; the ratio of the amount of the above-mentioned water to the amount of the dinitro compound is 9 - 11 mL:1 g; the above-mentioned drying is preferably vacuum drying, the temperature of the above-mentioned drying is preferably 75 - 85 °C, more preferably 80 °C, and the time is preferably 23 - 25 h, more preferably 24 h.

[0086] As an optional implementation mode of the present invention, the first catalyst is one of concentrated sulfuric acid, trifluoroacetic acid, methanesulfonic acid, and trifluoromethanesulfonic acid, and preferably methanesulfonic acid;

[0087] And / or, the pyridine source is one of 2-chloro-5-nitropyridine, 2-chloro-3-methyl-5-nitropyridine, 2-chloro-3-trifluoromethyl-5-nitropyridine, 2-chloro-3-fluoro-5-nitropyridine, 2,3-dichloro-5-nitropyridine, and 2-chloro-3-bromo-5-nitropyridine;

[0088] And / or, the base includes at least one of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, sodium bicarbonate, and potassium bicarbonate;

[0089] And / or, the first organic solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide;

[0090] And / or, the hydrogenation catalyst includes at least one of palladium-carbon, platinum-carbon, rhodium-carbon, and active nickel;

[0091] And / or, the second organic solvent includes at least one of tetrahydrofuran, ethanol, methanol, isopropanol, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, 1,4-dioxane, ethyl acetate, benzene, toluene, and xylene;

[0092] And / or, the reducing agent is hydrazine hydrate, and preferably the hydrazine hydrate is added in the form of an aqueous solution of hydrazine hydrate.

[0093] As an alternative embodiment of the present invention, the molar ratio of 1,3-adamantanediol to the phenol is 1:8;

[0094] And / or, the molar ratio of 1,3-bis(4-hydroxyphenyl)adamantane to the base is 1:1.2 to 3.0;

[0095] And / or, the molar ratio of 1,3-bis(4-hydroxyphenyl)adamantane to the pyridine source is 1:2 to 2.2;

[0096] The mass ratio of 1,3-bis(4-hydroxyphenyl)adamantane to the amount of the first organic solvent used is 1 g: 9 to 11 mL, preferably 1 g: 10 mL;

[0097] And / or, the mass percentage content of the metal element in the palladium-carbon, platinum-carbon, and rhodium-carbon is preferably 5 to 10%;

[0098] And / or, the mass of the hydrogenation catalyst is 10 to 15% of the mass of the dinitro compound;

[0099] And / or, the mass concentration of the aqueous solution of hydrazine hydrate is 80 to 99%, preferably 98%;

[0100] And / or, the molar ratio of the dinitro compound to the hydrazine hydrate in the aqueous solution of hydrazine hydrate is 1:4 to 12, preferably 1:10.

[0101] When the first organic solvent is two or more of the above specific selections, the present invention has no special limitation on the ratio of 1,3-bis(4-hydroxyphenyl)adamantane, the pyridine source, and the base, and they can be mixed in any ratio.

[0102] The present invention has no special limitation on the amount of the first organic solvent used, as long as it can ensure the smooth progress of the reaction.

[0103] Among them, the base plays a catalytic role and can promote the substitution reaction; when the base is two or more of the above specific selections, the present invention has no special limitation on the ratio of 1,3-bis(4-hydroxyphenyl)adamantane, the pyridine source, and the first organic solvent, and they can be mixed in any ratio.

[0104] When two or more of the above specific hydrogenation catalysts are used, the present invention does not impose any special limitation on the ratio of the dinitro compound containing an adamantyl group and a pyridine heterocyclic structure, the second organic solvent, and the reducing agent, and they can be mixed in any ratio.

[0105] When two or more of the above specific second organic solvents are used, the present invention does not impose any special limitation on the ratio of the dinitro compound containing an adamantyl group and a pyridine heterocyclic structure, the hydrogenation catalyst, and the reducing agent, and they can be mixed in any ratio.

[0106] According to the third aspect of the present invention, there is provided a polyimide, and the raw materials for synthesizing the polyimide include the aromatic diamine monomer as described above or the aromatic diamine monomer prepared by the preparation method of the aromatic diamine monomer as described above;

[0107] The structural formula of the polyimide is as follows:

[0108]

[0109] Wherein, R is one of -H, C1-6 alkyl, halogenated C1-6 alkyl, -F, -Cl, and -Br, preferably -CH3 or -CF3;

[0110] A is

[0111] As an optional embodiment of the present invention, the number average molecular weight of the polyimide is 5.3 - 10.4×10 4 g / mol;

[0112] And / or, the glass transition temperature (Tg) of the polyimide is 222 - 301 °C;

[0113] And / or, the temperature of 5% thermal weight loss of the polyimide is 470 - 520 °C;

[0114] And / or, the temperature of 10% thermal weight loss of the polyimide is 486 - 550 °C;

[0115] And / or, the dielectric constant of the polyimide at 10 GHz is 2.56 - 3.10;

[0116] And / or, the cut-off wavelength of the polyimide is 343 - 385 nm;

[0117] And / or, the polyimide is soluble in an aprotic polar solvent, which includes at least one of N,N-dimethylacetamide, N-methylpyrrolidone, N,N-dimethylformamide, m-cresol, butyrolactone and sulfolane, preferably including at least one of N,N-dimethylacetamide, N-methylpyrrolidone, N,N-dimethylformamide and m-cresol.

[0118] According to the fourth aspect of the present invention, there is provided a method for preparing the polyimide as described above, comprising the following steps:

[0119] Thermal imidization method: Under nitrogen protection, the aromatic diamine monomer and the aromatic dianhydride monomer are added to a third organic solvent for polycondensation reaction to obtain a polyamic acid solution. The polyamic acid solution is coated on a substrate, and then undergoes a dehydration cyclization reaction by gradient heating. After cooling, the film formed on the substrate is peeled off to synthesize a film-like polyimide.

[0120] Or,

[0121] Chemical imidization method: Under nitrogen protection, the aromatic diamine monomer and the aromatic dianhydride monomer are added to a third organic solvent for polycondensation reaction to obtain a polyamic acid solution. Then, a dehydrating agent and a catalyst are added to the polyamic acid solution, and after stirring at 80-100°C for 8-12 h, the obtained mixed solution is poured into ethanol for precipitation, and then filtered, washed and dried to obtain a fibrous or flocculent soluble polyimide.

[0122] The temperature of the polycondensation reaction is 23°C - 28°C, and the time of the polycondensation reaction is greater than or equal to 24 h;

[0123] And / or, the temperature of the dehydration cyclization of the polyamic acid is 60-300°C;

[0124] And / or, the time of the dehydration cyclization of the polyamic acid is 6-12 h, preferably 8 h.

[0125] Specifically, in the thermal imidization method, the temperature of the dehydration cyclization reaction by gradient heating is 60-300°C, and the temperature is gradually increased and maintained within this temperature range; the gradient heating can specifically be heating at 60°C for 8 hours, and then drying in a vacuum oven at 100°C, 150°C, 200°C, 250°C and 300°C for 30 min each.

[0126] In the chemical imidization method, after adding the dehydrating agent and the catalyst for reaction, the present invention preferably cools the obtained reaction solution to room temperature, mixes it with a polar solvent for precipitation, and then sequentially washes and dries the obtained precipitate to obtain a soluble polyimide.

[0127] The above polar solvent is preferably at least one of methanol, ethanol, and water, more preferably ethanol; the polar solvent is preferably 100 times the mass of the diamine; there are no special limitations on the washing in the present invention, as long as the third organic solvent can be removed. In the examples provided by the present invention, the washing solvent is preferably ethanol, the washing method is preferably soaking and stirring washing, and the number of washing times is preferably 3 times.

[0128] The process for preparing polyimide is a two-step method, that is, a polyamic acid solution is formed under stirring at room temperature without the need to convert the reaction equipment. Under heating conditions, a dehydrating agent and a catalyst are added to prepare polyimide.

[0129] Those skilled in the art can prepare the soluble polyimide into the required materials according to needs, such as films; in the examples provided by the present invention, the soluble polyimide is preferably prepared into a polyimide film. The preparation method of the polyimide film preferably includes the following steps:

[0130] Dissolve the soluble polyimide in an aprotic polar solvent to obtain a polyimide solution;

[0131] After defoaming the polyimide solution, coat it on a substrate and cure it to obtain a polyimide film.

[0132] As an alternative embodiment of the present invention, the aromatic dianhydride monomer is one of diphenyl ether tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, ester bond dianhydride, hexafluorodiacid dianhydride, pyromellitic dianhydride, and bisphenol A dianhydride;

[0133] And / or, the third organic solvent includes at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,4-butyrolactone.

[0134] Among them, when two or more of the above solvents are selected as the third organic solvent, the present invention has no special limitations on the specific ratios of the above substances, and they can be mixed in any ratio; the third organic solvent is preferably dried before use.

[0135] Among them, the present invention has no special limitations on the amount of the third organic solvent, as long as the reaction can proceed smoothly. In the examples provided by the present invention, the amount of the third organic solvent is preferably based on the solid content of the mixed solution obtained by mixing the aromatic diamine monomer, dianhydride monomer, and the third organic solvent.

[0136] The present invention does not have any special limitation on the mixing order of the aromatic diamine monomer, the dianhydride monomer and the third organic solvent, and the mixing order well-known to those skilled in the art can be adopted. In the embodiments provided by the present invention, the preferred mixing order of the aromatic diamine monomer, the third organic solvent and the dianhydride monomer is to mix the aromatic diamine monomer and the third organic solvent, and then mix the obtained mixture with the dianhydride monomer.

[0137] As an alternative embodiment of the present invention, the molar ratio of the aromatic diamine monomer to the dianhydride monomer is 1:1 to 1.3;

[0138] and / or, the molar ratio of the aromatic diamine monomer to the dianhydride monomer is preferably 1:1;

[0139] and / or, the solid content of the mixture obtained by mixing the aromatic diamine monomer, the dianhydride monomer and the third organic solvent is 10 to 25%.

[0140] According to the fifth aspect of the present invention, there is provided an application of the above polyimide or a polyimide prepared by the preparation method of the above polyimide in the preparation of polyimide film materials or electronic packaging materials.

[0141] In the present invention, the soluble polyimide formed by the above dianhydride monomer and the aromatic diamine monomer containing an adamantyl group and a pyridine heterocyclic structure has a low dielectric constant and excellent optical properties, and can be used for preparing polyimide film materials or electronic packaging materials.

[0142] The present invention will be further described in detail below with specific examples and comparative examples.

[0143] Example 1

[0144] Preparation of an aromatic diamine monomer containing an adamantane structure and a trifluoromethylpyridine heterocycle:

[0145] (a) Under nitrogen sweeping, 16.5 g of 1,3 - adamantanediol (0.10 mol) and 75 g of phenol (0.8 mol) were added to a 250 ml three - necked flask equipped with mechanical stirring. The temperature was raised to 90 °C. After the phenol melted, 9.6 g (0.20 mol) of methanesulfonic acid was added while stirring. The reaction was carried out at this temperature for 8 h. Then the reaction product was poured into 500 ml of deionized water, and a white - pink precipitate was formed. The product was filtered and washed with deionized water several times. The washed precipitate was dissolved in 200 ml of ethyl acetate, and then 500 mL of n - heptane solution was added thereto, and a white precipitate was formed. After stirring at room temperature for 30 min, it was filtered. The crude product was recrystallized from toluene and then vacuum - dried at 100 °C for 8 hours, thus obtaining 26.4 g of the intermediate adamantanebisphenol compound 1,3 - bis(4 - hydroxyphenyl)adamantane (white crystals), and the yield was 84% (the yield here was obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound).

[0146] (b) Under nitrogen protection, 10 g of the adamantanebisphenol compound 1,3 - bis(4 - hydroxyphenyl)adamantane (31.2 mmol) and 50 ml of DMF were added to a 250 ml three - necked flask equipped with magnetic stirring. After the solid was completely dissolved, 8.6 g of anhydrous K2CO3 (62.4 mmol) was added. At this time, the colorless solution became a white turbid solution. After the temperature was raised to 100 °C and reacted for 30 min, 14.07 g of 2 - chloro - 3 - trifluoromethyl - 5 - nitropyridine (62.4 mmol) was added, and the solution turned yellow - green. After reacting at this temperature for 8 h, it was then cooled and poured into a methanol - water (volume ratio 1:1) solution, and a white - yellow precipitate was formed. The crude product was filtered and recrystallized from tetrahydrofuran - water (volume ratio 1:3) to obtain 19.4 g of 1,3 - bis[4 - (2 - trifluoromethyl - 4 - nitropyridyloxy)phenyl]adamantane, and the yield was 89% (the yield here was obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound).

[0147] The 1,3 - bis[4 - (2 - trifluoromethyl - 4 - nitropyridyloxy)phenyl]adamantane obtained in this example was characterized by NMR, and the results are as follows: 1 HNMR(600MHz, CDCl3)δ:8.58(s,2H),8.29 - 8.27(d,2H),7.50 - 7.48(d,4H),7.09 - 7.08(d,4H),6.95 - 6.94(d,2H),2.39(s,2H),2.06(s,2H),2.00(s,8H),1.83(s,2H). 1313C NMR (600 MHz, CDCl3): δ = 161.33, 151.89, 148.47, 141.56, 128.75, 127.06, 123.80, 120.35, 116.93, 49.25, 42.23, 37.25, 35.63, 29.45.

[0148] (c) 10 g of the dinitro compound 1,3-bis[4-(2-trifluoromethyl-4-nitrophenoxyphenyl)]adamantane (14.3 mmol) was dissolved in 80 mL of ethanol in a 250 mL three-necked flask equipped with a stirrer and a spherical condenser. Using 0.2 g of Pd / C (10 wt%) as a catalyst, the temperature was raised to the reflux state (80 °C); then 10 g of hydrazine hydrate solution was added to the reaction system within 30 min, and then the reaction was continued at a constant temperature for 8 h. TLC was used to determine the end of the reaction. Then, the palladium carbon was removed by hot filtration, water was added for precipitation, and then the precipitate was washed and filtered. Finally, the obtained solid was dried in a vacuum oven at 80 °C to obtain 8.4 g of a white powdery diamine monomer, 1,3-bis[4-(2-trifluoromethyl-4-aminophenoxyphenyl)]adamantane, with a yield of 92% (the yield here is obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound).

[0149] The 1,3-bis[4-(2-trifluoromethyl-4-aminophenoxyphenyl)]adamantane obtained in this example was characterized by NMR, and the results are as follows: 1 1H NMR (600 MHz, DMSO-d6) δ: 7.36 - 7.34 (d, 4H), 6.91 - 6.90 (d, 2H), 6.85 - 6.84 (d, 2H), 6.81 - 6.79 (d, 6H), 5.43 (s, 4H), 2.23 (s, 2H), 1.89 - 1.83 (s, 10H), 1.72 (s, 2H). 13 13C NMR (600 MHz, CDCl3): δ = 156.03, 146.56, 145.23, 142.20, 126.04, 122.31, 119.34, 117.39, 112.93, 49.44, 42.35, 36.86, 35.80, 29.56.

[0150] As Figure 1 shown, the infrared spectra of 1,3-bis[4-(2-trifluoromethyl-4-nitrophenoxyphenyl)]adamantane (AMTFDT) and the aromatic diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminophenoxyphenyl)]adamantane (AMTFDM) are shown. Among them, the peak at 3383 cm -1 represents the stretching vibration peak of the amino N-H, proving the success of the reduction reaction. At 2940 cm-1 The peak represents the C-H vibration absorption peak on adamantane, at 1616 cm -1 The peak represents the characteristic peak of the pyridine ring, at 1332 cm -1 The peak represents the stretching vibration absorption peak of the nitro group. After reduction, the characteristic absorption of the nitro group disappears. At 1271 cm -1 Represents the absorption vibration peak of C-O, 1132 cm -1 The peak represents the vibration absorption peak of -O-.

[0151] Example 2

[0152] Preparation method of diamine monomer containing adamantane structure and pyridine heterocycle, comprising the following steps:

[0153] (a) Under nitrogen sweeping, add 16.5 g of 1,3-adamantanediol (0.10 mol) and 75 g of phenol (0.8 mol) to a 250 ml three-necked flask equipped with mechanical stirring. Heat up to 80 °C. After the phenol melts, add 10 g of concentrated sulfuric acid while stirring. React at this temperature for 8 h, then pour the reactant into 500 ml of deionized water to precipitate a white-pink precipitate. Filter the product and wash it with deionized water multiple times. Dissolve the washed precipitate in 200 ml of ethyl acetate, then add 500 mL of n-heptane solution thereto to precipitate a white precipitate. Stir at room temperature for 30 min and then filter. The crude product is recrystallized from toluene and then vacuum dried at 100 °C for 8 hours to obtain the intermediate adamantane bisphenol compound 1,3-bis(4-hydroxyphenyl)adamantane (white crystal), and the yield is 87% (the yield here is obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound).

[0154] (b) Under nitrogen protection, 10 g of adamantane bisphenol compound 1,3-bis(4-hydroxyphenyl)adamantane (31.2 mmol) and 50 ml of DMF were added to a 250 ml three-necked flask equipped with a magnetic stirrer. After the solid was completely dissolved, 8.6 g of anhydrous K2CO3 (62.4 mmol) was added. At this time, the colorless solution became a white turbid liquid. After heating to 120 °C and reacting for 30 min, 9.89 g of 2-chloro-5-nitropyridine (62.4 mmol) was added, and the solution turned yellow-green. After reacting at this temperature for 8 h, it was then cooled and poured into a methanol-water (volume ratio 1:1) solution to precipitate a white-yellow precipitate. The crude product was filtered and recrystallized with tetrahydrofuran-water (volume ratio 1:3) to obtain 1,3-bis[4-(4-nitropyridyloxy)phenyl]adamantane, and the yield was 86% (the yield here was obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound). (c) 10 g of the dinitro compound 1,3-bis[4-(4-nitropyridyloxy)phenyl]adamantane (14.3 mmol) was dissolved in 60 ml of ethanol in a 250 mL three-necked flask equipped with a stirrer and a spherical condenser. Using 0.2 g of Pd / C (Pd content 10 wt%) as a catalyst, the temperature was raised to the reflux state (85 °C); then 10 g of hydrazine hydrate solution was added to the reaction system within 30 min, and then the reaction was continued at a constant temperature for 10 h. TLC method was used to determine the end of the reaction. Then, the palladium carbon was removed by hot filtration, water was added for precipitation, and then the precipitate was washed and filtered. Finally, the obtained solid was dried in a vacuum oven at 80 °C to obtain a white powdery diamine monomer, 1,3-bis[4-(4-aminopyridyloxy)phenyl]adamantane, and the yield was 91% (the yield here was obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound).

[0155] Example 3

[0156] Preparation of an aromatic diamine monomer containing an adamantane structure and a methylpyridine ring:

[0157] (a) Under nitrogen sweeping, 16.5 g of 1,3-adamantanediol (0.10 mol) and 75 g of phenol (0.8 mol) were added to a 250 ml three-necked flask equipped with a mechanical stirrer. The temperature was raised to 90 °C. After the phenol melted, 30 g (0.20 mol) of trifluoromethanesulfonic acid was added while stirring. The reaction was carried out at this temperature for 6 h. Then the reaction product was poured into 500 ml of deionized water, and a white-pink precipitate was formed. The product was filtered and washed with deionized water several times. The washed precipitate was dissolved in 200 ml of ethyl acetate, and then 500 mL of n-heptane solution was added thereto, and a white precipitate was formed. After stirring at room temperature for 30 min, it was filtered. The crude product was recrystallized from toluene and then dried under vacuum at 100 °C for 8 hours. Thus, 28 g of the intermediate adamantane bisphenol compound 1,3-bis(4-hydroxyphenyl)adamantane (white crystals) was obtained, and the yield was 86.% (the yield here was obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound).

[0158] (b) Under nitrogen protection, 10 g of the adamantane bisphenol compound 1,3-bis(4-hydroxyphenyl)adamantane (31.2 mmol) and 50 ml of DMF were added to a 250 ml three-necked flask equipped with a magnetic stirrer. After the solid was completely dissolved, 8.6 g of anhydrous K2CO3 (62.4 mmol) was added. At this time, the colorless solution became a white turbid solution. After the temperature was raised to 100 °C and reacted for 30 min, 10.77 g of 2-chloro-3-methyl-5-nitropyridine (62.4 mmol) was added, and the solution turned yellow-green. After reacting at this temperature for 8 h, it was then cooled and poured into a methanol-water (volume ratio 1:1) solution, and a white-yellow precipitate was formed. The crude product was filtered and recrystallized from tetrahydrofuran-water (volume ratio 1:3) to obtain 19.4 g of 1,3-bis[4-(2-methyl-4-nitropyridyloxy)phenyl]adamantane, and the yield was 89% (the yield here was obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound).

[0159] (c) In a 250 mL three-necked flask equipped with a stirrer and a spherical condenser, 10 g of the dinitro compound 1,3-bis[4-(2-methyl-4-nitrophenylpyridinyl)phenyl]adamantane (14.3 mmol) was dissolved in 80 mL of ethanol. Using 0.4 g of Pd / C (Pd content 10 wt%) as a catalyst, the temperature was raised to the reflux state (80 °C). Then, 10 g of hydrazine hydrate solution was added to the reaction system within 30 min, and then the reaction was continued at a constant temperature for 8 h. The TLC method was used to determine the end of the reaction. Then, the palladium carbon was removed by hot filtration, water was added for precipitation, and then the precipitate was washed and filtered. Finally, the obtained solid was dried in a vacuum oven at 80 °C to obtain 8.4 g of a yellow powdery diamine monomer, 1,3-bis[4-(2-methyl-4-aminopyridyloxy)phenyl]adamantane, with a yield of 92% (the yield here was obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound).

[0160] Example 4

[0161] Preparation of an aromatic diamine monomer containing an adamantane structure and a chloropyridine ring:

[0162] (a) Under nitrogen purge, 16.5 g of 1,3-adamantanediol (0.10 mol) and 75 g of phenol (0.8 mol) were added to a 250 ml three-necked flask equipped with a mechanical stirrer. The temperature was raised to 90 °C. After the phenol melted, 9.6 g (0.20 mol) of methanesulfonic acid was added while stirring. The reaction was carried out at this temperature for 8 h, and then the reactant was poured into 500 ml of deionized water to precipitate a white-pink precipitate. The product was filtered and washed with deionized water several times. The washed precipitate was dissolved in 200 ml of ethyl acetate, and then 500 mL of n-heptane solution was added thereto to precipitate a white precipitate. After stirring at room temperature for 30 min, it was filtered. The crude product was recrystallized from toluene and then vacuum dried at 100 °C for 8 hours to obtain 26.4 g of the intermediate adamantane bisphenol compound 1,3-bis(4-hydroxyphenyl)adamantane (white crystals) with a yield of 84% (the yield here was obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound).

[0163] (b) Under nitrogen protection, 10 g of adamantane bisphenol compound 1,3-bis(4-hydroxyphenyl)adamantane (31.2 mmol) and 60 ml of DMF were added to a 250 ml three-necked flask equipped with a magnetic stirrer. After the solid was completely dissolved, 8.6 g of anhydrous K2CO3 (62.4 mmol) was added. At this time, the colorless solution became a white turbid liquid. After heating to 120 °C and reacting for 30 min, 12.04 g of 2,3-dichloro-5-nitropyridine (62.4 mmol) was added, and the solution turned yellow-green. After reacting at this temperature for 8 h, it was then cooled and poured into an ethanol-water (volume ratio 1:1) solution to precipitate a white-yellow precipitate. The crude product was filtered and recrystallized with tetrahydrofuran-water (volume ratio 1:3) to obtain 19.8 g of 1,3-bis[4-(2-chloro-4-nitropyridyloxy)phenyl]adamantane, and the yield was 88% (the yield here was obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound).

[0164] (c) 12 g of the dinitro compound 1,3-bis[4-(2-chloro-4-nitropyridyloxy)phenyl]adamantane (14.3 mmol) was dissolved in 80 ml of ethanol in a 250 mL three-necked flask equipped with a stirrer and a spherical condenser. Using 0.2 g of Pd / C (Pd content 10 wt%) as a catalyst, the temperature was raised to the reflux state (85 °C); then 10 g of hydrazine hydrate solution was added to the reaction system within 30 min, and then the reaction was continued at a constant temperature for 8 h. The TLC method was used to determine the end of the reaction. Then, the palladium carbon was removed by hot filtration, water was added for precipitation, and then the precipitate was washed and filtered. Finally, the obtained solid was dried in a vacuum oven at 80 °C to obtain 8.4 g of a yellow powdery diamine monomer, which was 1,3-bis[4-(2-chloro-4-aminopyridyloxy)phenyl]adamantane, and the yield was 90% (the yield here was obtained from the ratio of the mass of the actually obtained intermediate compound to the mass of the theoretically obtained intermediate compound).

[0165] The yields and purities of the aromatic diamine monomers obtained in Examples 1-4 are shown in Table 1.

[0166] Table 1

[0167]

[0168]

[0169] According to Table 1, the diamine monomers synthesized in Examples 1 and 3 have high yields and are suitable for industrial production. Among them, the product obtained in Example 1 has a higher purity and also contains a trifluoromethyl group, which has strong polarity and electrophilicity. Therefore, 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane prepared in Example 1 is used as an example to illustrate the preparation of the polyimide polymer.

[0170] Example 5

[0171] In this example, the aromatic diamine monomer prepared in Example 1 was used to prepare polyimide polymers by thermal imidization method and chemical imidization method respectively. Since the adamantane diamine monomer containing trifluoromethyl prepared in Example 1 introduced both a large-volume adamantane structure and a trifluoromethyl group with relatively high electronegativity, it was expected to achieve excellent light transmittance and dielectric properties. The diamine monomers prepared in Examples 2, 3 and 4 had similar structures to the monomer prepared in Example 1, and both introduced a large-volume adamantane structure and side groups, which was beneficial to increasing the solubility of the polymer.

[0172] Preparation of polyimide polymer containing adamantane structure and trifluoromethyl pyridine ring:

[0173] (1) Thermal imidization method: Under the protection of nitrogen, 1 mmol of diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminophenylpyridyl)phenyl]adamantane was fully dissolved in N-methylpyrrolidone under stirring. At 25 °C, 1 mmol of diphenyl ether tetracarboxylic dianhydride was added. After stirring at 25 °C for 24 hours, the solution was filtered and cast on a glass plate. The glass plate was placed on a hot stage at 60 °C and heated for 8 hours, and then baked in a vacuum oven at 100 °C, 150 °C, 200 °C, 250 °C and 300 °C for 30 min each. After cooling, the film was immersed in deionized water, peeled off, and then dried at 150 °C for 2 hours to obtain a polyimide film (AMTFDM+ODPA(T)), with Mn being 10.2×10 4 g / mol.

[0174] (2) Chemical imidization method: Under the protection of nitrogen, 1 mmol of diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyl)phenyl]adamantane was fully dissolved in N-methylpyrrolidone under stirring. At 25 °C, 1 mmol of diphenyl ether tetracarboxylic dianhydride was added. After stirring at 25 °C for 24 hours, 4 ml of acetic anhydride and 2 ml of pyridine mixture were added, and the temperature was raised to 80 °C and stirred for 12 h. The solution was poured into a large amount of ethanol, filtered, and dried in vacuum at 80 °C. The dried product was dissolved in NMP to prepare a PI solution with a solid content of 15%. Subsequently, the film was spread on a glass plate with a scraper. After evaporating at 60 °C for 8 h, the film was vacuum dried at 140 °C for 5 h and at 200 °C for 5 h to completely remove the solvent. Then, the glass plate with the polyimide film was immersed in deionized water, and the polyimide film (AMTFDM+ODPA(C)) was peeled off, with Mn being 10.4×10 4 g / mol.

[0175] Table 2 shows the optical, dielectric, and thermal properties of the polyimide synthesized in this example. Table 3 shows the mechanical properties of the polyimide, and Table 4 shows the solubility of the Polyimide. The specific test methods are as follows:

[0176] Differential scanning calorimetry (DSC) was carried out on a Mettler DSC instrument. The melting point (mp.) of the diamine and the glass transition temperature (Tg) of the PI were evaluated under a nitrogen gas flow rate of 50 mL / min and a heating rate of 20 mL / min. Among them, Tg was taken from the second heating curve to eliminate the thermal history.

[0177] Thermogravimetric analysis (TGA) was performed on a Mettler TGA. The nitrogen flow rate was 50 mL / min, and it was carried out in N2 at a rate of 20 °C / min within the range of 50 - 800 °C.

[0178] The mechanical properties of 20 mm × 6 mm × 0.05 mm thin film samples were tested using a universal testing machine Instron5567A. The sensor was 100 N, and the tensile rate was 5 mm / min. Five groups were measured respectively, and their average values were taken.

[0179] The solubility was determined by dissolving 10 mg of the polyimide sample in the corresponding solvent (2 ml) and dissolving it at 25 °C for 24 hours.

[0180] The ultraviolet-visible spectrum was recorded in transmission mode using an ultraviolet / visible / near-infrared spectrophotometer Lambda 1050+ in the wavelength range of 250 - 800 nm.

[0181] The dielectric properties were tested by a network analyzer for the dielectric constant and dielectric loss at 10 GHz and 20 GHz at room temperature.

[0182] According to Figure 2 , for the infrared spectra of the polyimides (AMTFDM+ODPA(C), AMTFDM+ODPA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane with diphenyl ether tetracarboxylic dianhydride (ODPA), it can be seen that at the peaks of 2923 cm -1 and 2836 cm -1 are -C-H, at the peaks of 1779 cm -1 and 1727 cm -1 are -C=O, and at the peak of 1375 cm -1 is -C-N.

[0183] According to Figure 3, it is the DSC chart of the thermal performance curve of the polyimide (AMTFDM+ODPA(C), AMTFDM+ODPA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and diphenyl ether tetracarboxylic dianhydride (ODPA). The glass transition temperature of AMTFDM+ODPA(C) is 249 °C.

[0184] According to Figure 4 , it is the TGA chart of the thermal performance curve of the polyimide (AMTFDM+ODPA(C), AMTFDM+ODPA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and diphenyl ether tetracarboxylic dianhydride (ODPA). The 5% and 10% thermal weight loss temperatures of AMTFDM+ODPA(C) are 504 °C and 523 °C respectively.

[0185] According to Figure 5 , it is the ultraviolet spectrum chart of the polyimide (AMTFDM+ODPA(C), AMTFDM+ODPA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and diphenyl ether tetracarboxylic dianhydride (ODPA). The light transmittance at 450 nm is 76.3%.

[0186] Example 6

[0187] In this example, the aromatic diamine monomer prepared in Example 1 was used to prepare polyimide polymers by the thermal imidization method and the chemical imidization method respectively.

[0188] Preparation of polyimide polymer containing adamantane structure and trifluoromethyl pyridine ring:

[0189] (1) Thermal imidization method: Under the protection of nitrogen, 1 mmol of the diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane was fully dissolved in N-methylpyrrolidone with stirring. 1 mmol of benzophenone tetracarboxylic dianhydride was added at 25 °C. After stirring at 25 °C for 24 hours, the solution was filtered and cast on a glass plate. The glass plate was placed on a hot stage at 60 °C and heated for 8 hours, and then baked in a vacuum oven at 100 °C, 150 °C, 200 °C, 250 °C and 300 °C for 30 min each. After cooling, the film was immersed in deionized water, peeled off, and then dried at 150 °C for 2 hours to obtain a polyimide film (AMTFDM+BTDA(T)), and Mn is 8.2×10 4 g / mol.

[0190] (2) Chemical imide method: Under the protection of nitrogen, 1 mmol of diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane was fully dissolved in N-methylpyrrolidone with stirring. 1 mmol of benzophenone tetracarboxylic dianhydride was added at 25 °C. After stirring at 25 °C for 24 hours, a mixture of 4 ml of acetic anhydride and 2 ml of pyridine was added, and the temperature was raised to 80 °C and stirred for 12 h. The solution was poured into a large amount of ethanol, filtered, and dried in vacuo at 80 °C. The dried product was dissolved in NMP to prepare a PI solution with a solid content of 15%. Subsequently, the solution was cast on a glass plate with a spatula and evaporated at 60 °C for 8 h. Then the film was vacuum dried at 140 °C for 5 h and at 200 °C for 5 h to completely remove the solvent. The glass plate with the polyimide film attached was immersed in deionized water, and the polyimide film (AMTFDM + BTDA(C)) was peeled off, with Mn being 7.4×10 4 g / mol.

[0191] Table 2 shows the optical, dielectric, and thermal properties of the polyimide synthesized in this example, Table 3 shows the mechanical properties of the polyimide, and Table 4 shows the solubility of Polyimide. The specific test methods are the same as those in Example 5.

[0192] According to Figure 2 , for the infrared spectra of polyimides (AMTFDM + BTDA(C), AMTFDM + BTDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane with benzophenone tetracarboxylic dianhydride (BTDA), it can be seen that the peaks at 2923 cm -1 and 2836 cm -1 are for -C-H, the peaks at 1779 cm -1 and 1727 cm -1 are for -C=O, and the peak at 1375 cm -1 is for -C-N.

[0193] According to Figure 3 , for the DSC thermal property curves of polyimides (AMTFDM + BTDA(C), AMTFDM + BTDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane with benzophenone tetracarboxylic dianhydride (BTDA). The glass transition temperature of AMTFDM + BTDA(C) is 252 °C.

[0194] According to Figure 4, is the thermogravimetric curve TGA diagram of polyimide (AMTFDM + BTDA(C), AMTFDM + BTDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane with benzophenone tetracarboxylic dianhydride (BTDA). The 5% and 10% thermal weight loss temperatures of AMTFDM + BTDA(C) are 502 °C and 526 °C, respectively.

[0195] According to Figure 5 , is the ultraviolet spectrum diagram of polyimide (AMTFDM + BTDA(C), AMTFDM + BTDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane with benzophenone tetracarboxylic dianhydride (BTDA). The transmittance at 450 nm is 70.7%.

[0196] Example 7

[0197] In this example, the aromatic diamine monomer prepared in Example 1 was used to prepare polyimide polymers by the thermal imidization method and the chemical imidization method, respectively.

[0198] Preparation of polyimide polymer containing adamantane structure and trifluoromethyl pyridine ring

[0199] (1) Thermal imidization method: Under the protection of nitrogen, 1 mmol of diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane was fully dissolved in N-methylpyrrolidone under stirring. 1 mmol of bisphenol A dianhydride was added at 25 °C. After stirring at 25 °C for 24 hours, the solution was filtered and cast on a glass plate. The glass plate was placed on a hot stage at 60 °C and heated for 8 hours, and then baked in a vacuum oven at 100 °C, 150 °C, 200 °C, 250 °C and 300 °C for 30 min each. After cooling, the film was immersed in deionized water, peeled off, and then dried at 150 °C for 2 hours to obtain a polyimide film (AMTFDM + BPADA(T)), and Mn was 8.0×10 4 g / mol.

[0200] (2) Chemical imide method: Under the protection of nitrogen, 1 mmol of diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane was fully dissolved in N-methylpyrrolidone under stirring. 1 mmol of bisphenol A dianhydride was added at 25 °C and stirred at 25 °C for 24 hours. Then, a mixture of 4 ml of acetic anhydride and 2 ml of pyridine was added, and the temperature was raised to 80 °C and stirred for 12 h. The solution was poured into a large amount of ethanol, filtered, and dried in vacuo at 80 °C. The dried product was dissolved in NMP to prepare a PI solution with a solid content of 15%. Subsequently, the solution was cast on a glass plate with a scraper and evaporated at 60 °C for 8 h. Then, the film was vacuum dried at 140 °C for 5 h and at 200 °C for 5 h to completely remove the solvent. The glass plate with the polyimide film was immersed in deionized water, and the polyimide film (AMTFDM+BPADA(C)) was peeled off. The Mn was 9.8×10 4 g / mol.

[0201] Table 2 shows the optical properties, dielectric properties, and thermal properties of the polyimide synthesized in this example. Table 3 shows the mechanical properties of the polyimide, and Table 4 shows the solubility of the polyimide. The specific test methods are the same as those in Example 5.

[0202] According to Figure 2 , for the infrared spectra of the polyimides (AMTFDM+BPADA(C), AMTFDM+BPADA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and bisphenol A dianhydride (BPADA), it can be seen that the peaks at 2923 cm -1 and 2836 cm -1 are -C-H, the peaks at 1779 cm -1 and 1727 cm -1 are -C=O, and the peak at 1375 cm -1 is -C-N.

[0203] According to Figure 3 , for the DSC thermal property curves of the polyimides (AMTFDM+BPADA(C), AMTFDM+BPADA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and bisphenol A dianhydride (BPADA), the glass transition temperature of AMTFDM+BPADA(C) is 222 °C.

[0204] According to Figure 4, it is the TGA graph of the thermal performance curve of polyimide (AMTFDM+BPADA(C), AMTFDM+BPADA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and bisphenol A dianhydride (BPADA). The 5% and 10% thermal weight loss temperatures of AMTFDM+BPADA(C) are 509 °C and 524 °C respectively.

[0205] According to Figure 5 , it is the ultraviolet spectrum of polyimide (AMTFDM+BPADA(C), AMTFDM+BPADA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and bisphenol A dianhydride (BPADA). The light transmittance at 450 nm is 75.5%.

[0206] Example 8

[0207] In this example, the aromatic diamine monomer prepared in Example 1 was used to prepare polyimide polymers by the thermal imidization method and the chemical imidization method respectively.

[0208] Preparation of polyimide polymer containing adamantane structure and trifluoromethyl pyridine ring

[0209] (1) Thermal imidization method: Under the protection of nitrogen, 1 mmol of diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane was fully dissolved in N-methylpyrrolidone under stirring. At 25 °C, 1 mmol of ester bond dianhydride (p-phenylene-bis(trimellitate dianhydride)) was added. After stirring at 25 °C for 24 hours, the solution was filtered and cast on a glass plate. The glass plate was placed on a hot stage at 60 °C and heated for 8 hours, and then baked in a vacuum oven at 100 °C, 150 °C, 200 °C, 250 °C and 300 °C for 30 min each. After cooling, the film was immersed in deionized water, peeled off, and then dried at 150 °C for 2 hours to obtain a polyimide film (AMTFDM+TAHQ(T)), and Mn is 7.9×10 4 g / mol.

[0210] (2) Chemical imide method: Under the protection of nitrogen, 1 mmol of diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminophenoxyphenyl)]adamantane was fully dissolved in N-methylpyrrolidone with stirring. 1 mmol of ester bond dianhydride was added at 25 °C. After stirring at 25 °C for 24 hours, a mixture of 4 ml of acetic anhydride and 2 ml of pyridine was added, and the temperature was raised to 80 °C and stirred for 12 h. The solution was poured into a large amount of ethanol, filtered, and dried in vacuo at 80 °C. The dried product was dissolved in NMP to prepare a PI solution with a solid content of 15%. Subsequently, the solution was cast on a glass plate with a spatula and evaporated at 60 °C for 8 h. Then the film was vacuum dried at 140 °C for 5 h and at 200 °C for 5 h to completely remove the solvent. The glass plate with the polyimide film was immersed in deionized water and the polyimide film (AMTFDM+TAHQ(C)) was peeled off, with Mn being 5.3×10 4 g / mol.

[0211] Table 2 shows the optical, dielectric and thermal properties of the polyimide synthesized in this example, Table 3 shows the mechanical properties of the polyimide, and Table 4 shows the solubility of the polyimide. The specific test methods are the same as those in Example 5.

[0212] According to Figure 2 , for the infrared spectra of the polyimides (AMTFDM+TAHQ(C), AMTFDM+TAHQ(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane with ester bond dianhydride (TAHQ), it can be seen that the peaks at 2923 cm -1 and 2836 cm -1 are for -C-H, the peaks at 1779 cm -1 and 1727 cm -1 are for -C=O, and the peak at 1375 cm -1 is for -C-N.

[0213] According to Figure 3 , for the DSC thermal property curves of the polyimides (AMTFDM+TAHQ(C), AMTFDM+TAHQ(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane with ester bond dianhydride (TAHQ), the glass transition temperature of AMTFDM+TAHQ(C) is 237 °C.

[0214] According to Figure 4, it is the TGA graph of the thermal performance curve of the polyimide (AMTFDM+TAHQ(C), AMTFDM+TAHQ(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane with ester bond dianhydride (TAHQ). The 5% and 10% thermal weight loss temperatures of AMTFDM+TAHQ(C) are 470 °C and 488 °C respectively.

[0215] According to Figure 5 , it is the UV spectrum of the polyimide (AMTFDM+TAHQ(C), AMTFDM+TAHQ(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane with ester bond dianhydride (TAHQ). The transmittance at 450 nm is 58.5%.

[0216] Example 9

[0217] In this example, the aromatic diamine monomer prepared in Example 1 was used to prepare polyimide polymers by the thermal imidization method and the chemical imidization method respectively.

[0218] Preparation of Polyimide Polymer Containing Adamantane Structure and Trifluoromethyl Pyridine Ring

[0219] (1) Thermal imidization method: Under the protection of nitrogen, 1 mmol of the diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane was fully dissolved in N-methylpyrrolidone with stirring. At 25 °C, 1 mmol of 2,3,3',4'-biphenyltetracarboxylic dianhydride was added. After stirring at 25 °C for 24 hours, the solution was filtered and cast on a glass plate. The glass plate was placed on a hot stage at 60 °C and heated for 8 hours, and then baked in a vacuum oven at 100 °C, 150 °C, 200 °C, 250 °C and 300 °C for 30 min each. After cooling, the film was immersed in deionized water, peeled off, and then dried at 150 °C for 2 hours to obtain a polyimide film (AMTFDM+α-BPDA(T)), and Mn was 10.4×10 4 g / mol.

[0220] (2) Chemical imide method: Under the protection of nitrogen, 1 mmol of diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane was fully dissolved in N-methylpyrrolidone under stirring. At 25 °C, 1 mmol of 2,3,3',4'-biphenyltetracarboxylic dianhydride was added. After stirring at 25 °C for 24 hours, a mixture of 4 ml of acetic anhydride and 2 ml of pyridine was added, and the temperature was raised to 80 °C and stirred for 12 h. The solution was poured into a large amount of ethanol, filtered, and dried in vacuo at 80 °C. The dried product was dissolved in NMP to prepare a PI solution with a solid content of 15%. Subsequently, the solution was cast on a glass plate with a spatula, and after evaporation at 60 °C for 8 h, the film was vacuum dried at 140 °C for 5 h and then at 200 °C for 5 h to completely remove the solvent. The glass plate with the polyimide film attached was immersed in deionized water, and the polyimide film (AMTFDM+α-BPDA(C)) was peeled off, with Mn being 9.7×10 4 g / mol.

[0221] Table 2 shows the optical properties, dielectric properties, and thermal properties of the polyimide synthesized in this example, Table 3 shows the mechanical properties of the polyimide, and Table 4 shows the solubility of the polyimide. The specific test methods are the same as those in Example 5.

[0222] According to Figure 2 , for the infrared spectra of the polyimides (AMTFDM+α-BPDA(C), AMTFDM+α-BPDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and biphenyltetracarboxylic dianhydride (α-BPDA), it can be seen that the peaks at 2923 cm -1 and 2836 cm -1 are for -C-H, the peaks at 1779 cm -1 and 1727 cm -1 are for -C=O, and the peak at 1375 cm -1 is for -C-N.

[0223] According to Figure 3 , for the DSC thermal performance curve of the polyimides (AMTFDM+α-BPDA(C), AMTFDM+α-BPDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and biphenyltetracarboxylic dianhydride (α-BPDA). Among them, its glass transition temperature is 269 °C.

[0224] According to Figure 4, is the TGA graph of the thermal performance curve of the polyimide (AMTFDM+α-BPDA(C), AMTFDM+α-BPDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and biphenyltetracarboxylic dianhydride (α-BPDA). The thermal weight loss temperatures at 5% and 10% are 519 °C and 537 °C respectively.

[0225] According to Figure 5 , is the ultraviolet spectrum diagram of the polyimide (AMTFDM+α-BPDA(C), AMTFDM+α-BPDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and biphenyltetracarboxylic dianhydride (α-BPDA). The transmittance at 450 nm is 73.8%.

[0226] Example 10

[0227] In this example, the aromatic diamine monomer prepared in Example 1 was used to prepare polyimide polymers by the thermal imidization method and the chemical imidization method respectively.

[0228] Preparation of polyimide polymer containing adamantane structure and trifluoromethyl pyridine ring

[0229] (1) Thermal imidization method: Under the protection of nitrogen, 1 mmol of the diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane was fully dissolved in N-methylpyrrolidone with stirring. 1 mmol of hexafluorodiacid anhydride was added at 25 °C. After stirring at 25 °C for 24 hours, the solution was filtered and cast on a glass plate. The glass plate was placed on a hot stage at 60 °C and heated for 8 hours, and then baked in a vacuum oven at 100 °C, 150 °C, 200 °C, 250 °C and 300 °C for 30 min each. After cooling, the film was immersed in deionized water, peeled off, and then dried at 150 °C for 2 hours to obtain a polyimide film (AMTFDM+6FDA(T)), and Mn was 8.6×10 4 g / mol.

[0230] (2) Chemical imide method: Under the protection of nitrogen, 1 mmol of diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane was fully dissolved in N-methylpyrrolidone under stirring. 1 mmol of hexafluorodiacid anhydride was added at 25 °C. After stirring at 25 °C for 24 hours, a mixture of 4 ml of acetic anhydride and 2 ml of pyridine was added, and the temperature was raised to 80 °C and stirred for 12 h. The solution was poured into a large amount of ethanol, filtered, and dried in vacuo at 80 °C. The dried product was dissolved in NMP to prepare a PI solution with a solid content of 15%. Subsequently, the film was spread on a glass plate with a spatula. After evaporating for 8 h at 60 °C, the film was vacuum dried at 140 °C for 5 h and then at 200 °C for 5 h to completely remove the solvent. The glass plate with the polyimide film attached was immersed in deionized water, and the polyimide film (AMTFDM+6FDA(C)) was peeled off. The Mn was 9.5×10 4 g / mol.

[0231] Table 2 shows the optical properties, dielectric properties, and thermal properties of the polyimide synthesized in this example. Table 3 shows the mechanical properties of the polyimide, and Table 4 shows the solubility of the polyimide. The specific test methods are the same as those in Example 5.

[0232] According to Figure 3 , it is the DSC diagram of the thermal performance curve of the polyimide (AMTFDM+6FDA(C), AMTFDM+6FDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and hexafluorodiacid anhydride (6FDA). The glass transition temperature of AMTFDM+ODPA(C) is 273 °C.

[0233] According to Figure 4 , it is the TGA diagram of the thermal performance curve of the polyimide (AMTFDM+6FDA(C), AMTFDM+6FDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and hexafluorodiacid anhydride (6FDA). The 5% and 10% thermal weight loss temperatures of AMTFDM+6FDA(C) are 504 °C and 523 °C, respectively.

[0234] According to Figure 5 , it is the ultraviolet spectrum diagram of the polyimide (AMTFDM+6FDA(C), AMTFDM+6FDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and hexafluorodiacid anhydride (6FDA). The transmittance of AMTFDM+6FDA(T) at 450 nm is 76.3%.

[0235] Example 11

[0236] When preparing polyimide polymers using pyromellitic dianhydride (PMDA) by the chemical imide method, gelation occurs and subsequent characterization cannot be carried out. Therefore, in this example, the aromatic diamine monomer prepared in Example 1 was used to prepare polyimide polymers by the thermal imide method.

[0237] Preparation of polyimide polymers containing adamantane structure and trifluoromethyl pyridine ring:

[0238] (1) Thermal imide method: Under the protection of nitrogen, 1 mmol of diamine monomer 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane was fully dissolved in N-methylpyrrolidone with stirring. At 25 °C, 1 mmol of pyromellitic dianhydride (PMDA) was added. After stirring at 25 °C for 24 hours, the solution was filtered and cast on a glass plate. The glass plate was placed on a hot stage at 60 °C and heated for 8 hours, and then baked in a vacuum oven at 100 °C, 150 °C, 200 °C, 250 °C, and 300 °C for 30 min each. After cooling, the film was immersed in deionized water, peeled off, and then dried at 150 °C for 2 hours to obtain a polyimide film (AMTFDM+PMDA(T)), with Mn being 6.5×104 g / mol.

[0239] Table 2 shows the optical properties (Optical), dielectric properties (Dielectric), and thermal properties (Thermal) of the polyimide synthesized in this example. Table 3 shows the mechanical properties of the polyimide, and Table 4 shows the solubility of the polyimide. The specific test methods are the same as those in Example 5.

[0240] According to Figure 3 , it is the DSC diagram of the thermal performance curve of the polyimide (AMTFDM+PMDA(T)) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and pyromellitic dianhydride (PMDA). The glass transition temperature of AMTFDM+PMDA(T) is 301 °C.

[0241] According to Figure 4 , it is the TGA diagram of the thermal performance curve of the polyimide AMTFDM+PMDA(T) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and pyromellitic dianhydride (PMDA). The 5% and 10% thermal weight loss temperatures of AMTFDM+PMDA(T) are 518 °C and 533 °C, respectively.

[0242] According to Figure 5, it is the ultraviolet spectrum diagram of polyimide AMTFDM+6FDA(T) prepared by the reaction of 1,3-bis[4-(2-trifluoromethyl-4-aminopyridyloxy)phenyl]adamantane and pyromellitic dianhydride (PMDA). Among them, the transmittance of AMTFDM+PMDA(T) at 450 nm is 18.3%.

[0243] Comparative Example 1

[0244] This comparative example is the commercially available Kapton film in the prior art. Its optical properties, dielectric properties, thermal properties, mechanical properties and solubility are tested by exactly the same test methods as those in Examples 5-10, as shown in Tables 2-4 specifically.

[0245] Table 2 Optical properties, dielectric properties and thermal properties of polyimides synthesized in Examples 5-11 and Comparative Example 1

[0246]

[0247]

[0248] Table 3 Mechanical properties of polyimides synthesized in Examples 5-11 and Comparative Example 1

[0249]

[0250]

[0251] Table 4 Solubility of polyimides synthesized in Examples 5-11 and Comparative Example 1

[0252]

[0253] Note: +: Dissolve at room temperature; +-: Partially dissolve or swell; -: Do not dissolve.

[0254] It can be seen from Table 2 that compared with Comparative Example 1, the polyimide prepared in Examples 5-11 provided by the present invention has more excellent optical properties, indicating that the polyimide prepared by the present invention has better light transparency and can meet the requirements for polyimide films in the optical field.

[0255] It can be seen from Table 2 that compared with Comparative Example 1, the polyimide prepared in Examples 5-11 provided by the present invention has more excellent dielectric properties, indicating that the polyimide prepared by the present invention has a lower dielectric constant. The lower the dielectric constant, the better the charge transfer effect, and it can be used in electronic packaging materials.

[0256] As can be seen from Table 2, compared with Comparative Example 1, the polyimides prepared in Examples 5-11 provided by the present invention have little difference in thermal properties, indicating that the polyimides prepared by the present invention all have a relatively high glass transition temperature and can be applied at a relatively high temperature, with a wider range of applicability.

[0257] As can be seen from Table 3, compared with Comparative Example 1, the polyimides prepared in Examples 5-11 provided by the present invention exhibit more excellent certain mechanical properties, indicating that the polyimides prepared by the present invention have properties such as high strength, high modulus, corrosion resistance, wear resistance, and light weight.

[0258] As can be seen from Table 4, compared with Comparative Example 1, the polyimides prepared in Examples 5-11 provided by the present invention all have good solubility in specific solvents, indicating that the polyimides prepared by the present invention are easy to process and have a wider range of applicability.

[0259] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An aromatic diamine monomer, characterized in that, It includes adamantyl, pyridine heterocycle and flexible ether bond, and the structural formula of the aromatic diamine monomer is as follows: Wherein, R is one of -H, C1-6 alkyl, halogenated C1-6 alkyl, -F, -Cl and -Br, preferably -CH3 or -CF3.

2. A method for preparing the aromatic diamine monomer according to claim 1, characterized in that, It includes the following steps: S1: Under a protective atmosphere, add 1,3-adamantanediol and phenol into a reaction vessel equipped with mechanical stirring, further add a first catalyst, heat up to 80-90 °C and react for 6-12 h, then end the reaction. After sedimentation, filtration, drying and recrystallization, 1,3-bis(4-hydroxyphenyl)adamantane can be obtained; S2: Mix the 1,3-bis(4-hydroxyphenyl)adamantane, the pyridine source containing nitro and a base in a first organic solvent, and carry out a substitution reaction at a temperature of 80-120 °C for 8-12 h to obtain a dinitro compound; S3: Mix the dinitro compound, a hydrogenation catalyst, a second organic solvent and a reducing agent, and carry out a catalytic hydrogenation reaction at a temperature of 40-100 °C for 8-12 h to obtain the aromatic diamine monomer.

3. According to the method for preparing the aromatic diamine monomer described in claim 2, characterized in that, The first catalyst is one of concentrated sulfuric acid, trifluoroacetic acid, methanesulfonic acid or trifluoromethanesulfonic acid, preferably methanesulfonic acid; And / or, the pyridine source is one of 2-chloro-5-nitropyridine, 2-chloro-3-methyl-5-nitropyridine, 2-chloro-3-trifluoromethyl-5-nitropyridine, 2-chloro-3-fluoro-5-nitropyridine, 2,3-dichloro-5-nitropyridine and 2-chloro-3-bromo-5-nitropyridine; And / or, the base includes at least one of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, sodium bicarbonate and potassium bicarbonate; And / or, the first organic solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide; And / or, the hydrogenation catalyst includes at least one of palladium carbon, platinum carbon, rhodium carbon and active nickel; And / or, the second organic solvent includes at least one of tetrahydrofuran, ethanol, methanol, isopropanol, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, 1,4-dioxane, ethyl acetate, benzene, toluene and xylene; And / or, the reducing agent is hydrazine hydrate, and preferably the hydrazine hydrate is added in the form of an aqueous hydrazine hydrate solution.

4. According to the method for preparing the aromatic diamine monomer described in claim 3, characterized in that, The molar ratio of the 1,3-adamantanediol to the phenol is 1:8; And / or, the molar ratio of the 1,3-bis(4-hydroxyphenyl)adamantane to the base is 1:1.2-3.0; And / or, the molar ratio of the 1,3-bis(4-hydroxyphenyl)adamantane to the pyridine source is 1:2-2.2; The mass ratio of the 1,3-bis(4-hydroxyphenyl)adamantane to the dosage of the first organic solvent is 1 g:9-11 mL, preferably 1 g:10 mL; And / or, the mass percentage content of the metal element in the palladium carbon, platinum carbon and rhodium carbon is preferably 5-10%; And / or, the mass of the hydrogenation catalyst is 10-15% of the mass of the dinitro compound. And / or, the mass concentration of the aqueous hydrazine solution is 80-99%, preferably 98%; And / or, the molar ratio of the dinitro compound to hydrazine in the aqueous hydrazine solution is 1:4-12, preferably 1:

10.

5. A polyimide, characterized in that, The raw materials for synthesizing the polyimide include the aromatic diamine monomer as described in claim 1 or the aromatic diamine monomer prepared by the preparation method of the aromatic diamine monomer as described in any one of claims 2-4; The structural formula of the polyimide is as follows: Wherein, R is one of -H, C1-6 alkyl, halogenated C1-6 alkyl, -F, -Cl and -Br, preferably -CH3 or -CF3; A is 6. According to the polyimide described in claim 5, characterized in that, The number-average molecular weight of the polyimide is 5.3 - 10.4×10 4 g / mol; And / or, the glass transition temperature (Tg) of the polyimide is 222-301 °C; And / or, the temperature of 5% thermal weight loss of the polyimide is 470-520 °C; And / or, the temperature of 10% thermal weight loss of the polyimide is 486-550 °C; And / or, the dielectric constant of the polyimide at 10 GHz is 2.56-3.10; And / or, the cut-off wavelength of the polyimide is 343-385 nm; And / or, the polyimide is soluble in aprotic polar solvents, and the aprotic polar solvents include at least one of N,N-dimethylacetamide, N-methylpyrrolidone, N,N-dimethylformamide, m-cresol, butyrolactone and sulfolane, preferably including at least one of N,N-dimethylacetamide, N-methylpyrrolidone, N,N-dimethylformamide and m-cresol.

7. A method for preparing a polyimide according to any one of claims 5-6, characterized in that, Comprising the following steps: Thermal imidization method: Under nitrogen protection, the aromatic diamine monomer and the aromatic dianhydride monomer are added to a third organic solvent for polycondensation reaction to obtain a polyamic acid solution, and then dehydration cyclization reaction is carried out by gradient heating to synthesize a film-like polyimide; Or, Chemical imidization method: Under nitrogen protection, the aromatic diamine monomer and the aromatic dianhydride monomer are added to a third organic solvent for polycondensation reaction to obtain a polyamic acid solution, then a dehydrating agent and a catalyst are added to the polyamic acid solution, and after stirring at 80-100 °C for 8-12 h, the obtained mixed solution is poured into ethanol for precipitation, filtered, washed and dried to obtain fibrous or flocculent polyimide; The temperature of the polycondensation reaction is 23 °C-28 °C, and the time of the polycondensation reaction is greater than or equal to 24 h; And / or, the temperature of polyamic acid dehydration cyclization is 60-300 °C; And / or, the time of polyamic acid dehydration cyclization is 6-12 h, preferably 8 h.

8. The method for preparing a polyimide according to claim 7, characterized in that, The aromatic dianhydride monomer is one of diphenyl ether tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, ester bond dianhydride, hexafluorodiacid dianhydride, pyromellitic dianhydride and bisphenol A dianhydride; And / or, the third organic solvent includes at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide and 1,4-butyrolactone.

9. The method for preparing a polyimide according to claim 7, characterized in that, The molar ratio of the aromatic diamine monomer to the aromatic dianhydride monomer is 1:1-1.3; And / or, the molar ratio of the aromatic diamine monomer to the aromatic dianhydride monomer is preferably 1:1; And / or, the solid content of the mixed solution obtained by mixing the aromatic diamine monomer, the aromatic dianhydride monomer and the third organic solvent is 10-25%.

10. Use of a polyimide according to any one of claims 5-6 or a polyimide prepared by the method for preparing a polyimide according to any one of claims 7-9 in the preparation of a polyimide film material or an electronic packaging material.

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