Preparation method of aromatic diamine monomer containing double trifluoromethyl, single methyl side group and meta benzene structure and polyimide thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHANGZHOU UNIV
- Filing Date
- 2026-03-27
- Publication Date
- 2026-06-19
Smart Images
Figure CN122233928A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the preparation of aromatic diamine monomers and their polymers, and particularly to a class of diamine monomers and polyimides containing bis(trifluoromethyl), monomethyl side groups and m-phenyl structures. Background Technology
[0002] Thanks to the strong bond energy of imide and aromatic structures, polyimide films possess glass transition temperatures above 200℃ and thermal decomposition temperatures exceeding 500℃, tensile strengths of up to 100MPa, and excellent creep resistance. Their low dielectric loss and dielectric constant indicate their promising potential applications, leading to their widespread use in electronics, aerospace, and microelectronics. However, with increasingly stringent requirements for materials across various fields, particularly in the core applications of polyimide, the miniaturization and integration of electronic devices are presenting increasingly demanding challenges to these superior properties, placing higher demands on their overall performance. Common polyimides, such as Kapton NH films, possess excellent thermodynamic and mechanical properties thanks to their imide bonds. However, this also results in poor solubility of polyimides, reducing the plasticity of the polymer. Their dielectric constant is 3.4 at 1 kHz, and an excessively high dielectric constant can lead to communication delays and distortions. Furthermore, the electron transfer complex (CTC) structure also causes the film to have a dark brown color, further limiting its high-performance applications in microelectronic devices.
[0003] Experiments have shown that adding functional side groups to polyimides can effectively regulate polymer properties. Fluorinated bulky side groups and alkyl side groups are often popular choices, as they can significantly reduce the dielectric constant and dielectric loss of the material. On the other hand, adding an isophenyl structure to the main chain is also an effective modification method. Compared with the usual p-phenyl structure, which promotes π=π stacking of molecular chains and the formation of hydrogen bond networks, adding a fixed angle to the main chain can disrupt the close packing, thereby improving the flexibility of the polymer. Summary of the Invention
[0004] This invention synthesizes a diamine monomer, 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene, and synthesizes a novel polyimide polymer by polymerizing it with equimolar amounts of diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A tetracarboxylic dianhydride, respectively. The invention introduces bis(trifluoromethyl) and monomethyl side groups and a m-phenylene structure into the polyimide.
[0005] This invention introduces methyl, trifluoromethyl, and meta structures through molecular structure design to increase the free volume of the polymer, improve the proportion of amorphous phase in the material, and reduce the close packing of molecular chains, in order to prepare a low-dielectric, highly transparent, flexible polyimide with good plasticity, while ensuring its appropriate thermodynamic and mechanical properties.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] An aromatic diamine monomer containing a bis(trifluoromethyl) group, a monomethyl side group, and a m-phenylene structure, wherein the aromatic diamine monomer 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene has the following structural formula:
[0008] .
[0009] The method for preparing aromatic diamine monomers containing bis(trifluoromethyl), monomethyl side groups, and m-phenyl structures includes the following steps:
[0010] (1) 2,6-dihydroxytoluene, 2-chloro-5-nitrotrifluorotoluene and a basic catalyst were mixed in an organic solvent, stirred and heated to 140-150°C for 4-8 h under a nitrogen atmosphere. After the reaction was completed, the product was poured into deionized water to settle for 10-14 h, then the solid was filtered out and washed with anhydrous ethanol and dried. Recrystallization yielded the dinitro intermediate 2,6-bis(4-nitro-2-trifluoromethylphenoxy)toluene.
[0011] Preferably, the alkaline catalyst in step (1) is an inorganic or organic base, more preferably an inorganic base; such as sodium carbonate, potassium carbonate, sodium hydroxide, or potassium hydroxide. The organic solvent is a high-boiling-point aprotic polar solvent, such as one or more of N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), or dimethyl sulfoxide (DMSO).
[0012] Preferably, the molar ratio of each raw material in step (1) is: 2,6-dihydroxytoluene: 2-chloro-5-nitrotrifluorotoluene: alkaline catalyst = 1:(2.0~2.2):(1.2~2.0).
[0013] (2) The dinitro intermediate 2,6-bis(4-nitro-2-trifluoromethylphenoxy)toluene, organic solvent and catalyst are placed in a reaction vessel, stirred and heated to 80~85°C under nitrogen protection, and the reducing agent is slowly added dropwise using a constant pressure dropping funnel. The reaction is carried out for 5~7 hours. After the reaction is completed, the product is allowed to stand and precipitate to obtain the product 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene.
[0014] Preferably, the catalyst in step (2) is a noble metal catalyst, such as palladium on carbon; its amount is 3% to 10% of the mass of the dinitro intermediate.
[0015] The reducing agent is hydrazine hydrate. Its dosage is 4 to 10 times the molar amount of the dinitro intermediate.
[0016] The organic solvent is preferably an alcohol solvent, such as methanol, anhydrous ethanol, or ethylene glycol methyl ether.
[0017] This invention also provides a class of polyimides containing bis(trifluoromethyl) and monomethyl side groups and an isophenyl structure, the structural formula of which is:
[0018]
[0019] in, It can be One of them, with repeating units n=30~100.
[0020] The preparation method of the above-mentioned polyimide polymer containing bis(trifluoromethyl) and monomethyl side groups and isophenyl structures includes the following specific steps:
[0021] Four types of polyimides were prepared by a one-step method. Diamine monomer and dianhydride were added to a three-necked flask, heated to 105-115°C (preferably 110°C), and stirred until the solid was completely dissolved in the solvent. Then, a catalyst was added, and the mixture was heated to 170-180°C (preferably 174°C) under a nitrogen atmosphere and reacted for 3-8 hours until the reactants became viscous. The viscous reaction product was poured into anhydrous ethanol to precipitate, yielding a white solid product. Finally, after drying, the polyimide product was obtained.
[0022] The diamine monomer containing bis(trifluoromethyl) and monomethyl side groups and m-phenyl structures is 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene, and the dianhydride is one of diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A dianhydride.
[0023] The organic solvent is m-cresol or N-methylpyrrolidone, and its amount is 7 to 15 times the total mass of the diamine and dianhydride monomers; the catalyst is isoquinoline, and its amount is 1% to 3% of the mass of the diamine.
[0024] The specific synthetic route for the aromatic diamine monomer and polyimide polymer containing bis(trifluoromethyl) and monomethyl side groups and m-phenyl structures of the present invention is as follows:
[0025] (1) Synthesis of diamine monomers containing bis(trifluoromethyl) and monomethyl side groups and m-phenyl structures:
[0026]
[0027]
[0028] (2) Synthesis of polymers containing bis(trifluoromethyl) and monomethyl side groups and isophenyl structures:
[0029]
[0030] The polyimide polymer film containing bis(trifluoromethyl) and monomethyl side groups and isophenyl structures of the present invention has important potential application value in the field of microelectronics.
[0031] The specific application method is as follows: add the polyimide polymer to an organic solvent to prepare a 5wt%~10wt% solution, filter it, coat it with a film, and dry it at 60~100℃ for 12~24 h to obtain a polyimide film material containing bis(trifluoromethyl), monomethyl side groups and isophenyl structures.
[0032] The beneficial effects of this invention are:
[0033] (1) The diamine monomer containing bis(trifluoromethyl) and monomethyl side groups and m-phenyl structures prepared by the present invention uses readily available starting materials, adopts a relatively simple synthetic route, and the product is easy to purify and separate, has a high yield, and is stable at room temperature.
[0034] (2) The polyimide membrane material prepared by the present invention can be obtained directly by one-step solution polycondensation to obtain polyimide polymer, without the need to convert polyamic acid into polyimide. The synthesis and preparation process is simple and easy to industrialize.
[0035] (3) The polyimide film material prepared by the present invention has good solubility, heat resistance and dielectric properties due to the introduction of bis(trifluoromethyl) and monomethyl side groups and isophenyl structure into the polymer molecular structure. The film prepared has potential application value in the field of microelectronics. Attached Figure Description
[0036] Figure 1 In the embodiments of the present invention, the intermediate dinitro compound and the diamine monomer 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene 1 H NMR spectrum.
[0037] Figure 2 In the examples, four polyimides PI-A~D were prepared by reacting the diamine monomer 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene with diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A tetracarboxylic dianhydride, respectively. 1 The H NMR spectra, from top to bottom, are PI-B, PI-A, PI-C, and PI-D.
[0038] Figure 3 The infrared spectra of the intermediate dinitro compound and the diamine monomer are shown in the examples.
[0039] Figure 4In this embodiment, the infrared spectra of four polyimides PI-A~D prepared by diamine monomer 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene with diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A tetracarboxylic dianhydride are shown.
[0040] Figure 5 The following are DSC curves of four polyimides PI-A~D prepared by diamine monomer 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene with diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A tetracarboxylic dianhydride, respectively, in the examples.
[0041] Figure 6 The graphs show the thermogravimetric curves of polyimides made from diamine monomers 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene and hexafluoroisopropyltetracarboxylic dianhydride under N2 and air, respectively, in the implementation case.
[0042] Figure 7 The images show the UV-Vis spectra of four polyimide PI-A~D films prepared from the diamine monomer 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene with diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A tetracarboxylic dianhydride, respectively, in the implementation case.
[0043] Figure 8 The graph shows the relationship between the dielectric constant and the electric field frequency of four polyimides PI-A~D prepared by diamine monomer 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene with diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A tetracarboxylic dianhydride, respectively. Detailed Implementation
[0044] Preferred embodiments of the present invention will now be described in more detail with reference to specific examples.
[0045] The following are the raw materials and pharmaceuticals used in the examples:
[0046] 2-Chloro-5-nitrotrifluorotoluene: Sinopharm Chemical Reagent Co., Ltd., purity 98%.
[0047] Anhydrous ethanol: Sinopharm Chemical Reagent Co., Ltd., purity 99%.
[0048] Hydrazine hydrate: Sinopharm Chemical Reagent Co., Ltd., purity ≥ 50%.
[0049] 2,6-Dihydroxytoluene: Saan Chemical Technology (Shanghai) Co., Ltd., 99% purity.
[0050] Pd / C catalyst: Shaanxi Kaida Chemical Co., Ltd., palladium content: 5.0%.
[0051] Diphenyl ether tetracarboxylic dianhydride: Nantong Juyan New Materials Co., Ltd., purity 99%.
[0052] Hexafluoroisopropyltetracarboxylic dianhydride: Nantong Juyan New Materials Co., Ltd., purity 99%.
[0053] Benzophenone tetracarboxylic dianhydride: Nantong Juyan New Materials Co., Ltd., purity 99%.
[0054] Bisphenol A tetracarboxylic dianhydride: Nantong Juyan New Materials Co., Ltd., purity 99%.
[0055] m-Cresol: Aladdin Reagent Co., Ltd., purity 99%.
[0056] Isoquinoline: Alfa Corporation, 99% purity.
[0057] N-Methylpyrrolidone, N,N-Dimethylacetamide: Shanghai Lingfeng Chemical Reagent Co., Ltd., purity 99%.
[0058] Example 1
[0059] (1) Preparation of aromatic diamine monomers containing bis(trifluoromethyl) and monomethyl side groups and m-phenyl structures
[0060] (a) 2,6-Dihydroxytoluene (12.414 g, 0.1 mol), 2-chloro-5-nitrotrifluorotoluene (45.11 g, 0.2 mol), and anhydrous sodium carbonate (15.89 g, 0.15 mol) were placed in a three-necked flask equipped with a reflux evaporator. 150 mL of DMAc was added to dissolve the solid in the three-necked flask, and the mixture was stirred and heated to 145 °C for 6 h under a nitrogen atmosphere. After the reaction was completed, the product was poured into 500 mL of deionized water to settle for 12 h. The solid was then filtered off and washed with anhydrous ethanol to obtain a crude product, which was dried for 24 h. The dried crude product was then recrystallized from a 1:1 mixture of DMAc and anhydrous ethanol to obtain the dinitro intermediate 2,6-bis(4-nitro-2-trifluoromethylphenoxy)toluene (MPTN) in 88% yield (the yield here is obtained by the ratio of the actual mass of the intermediate compound obtained to the theoretical mass of the intermediate compound).
[0061] (b) The dinitro intermediate (32.4 g, 0.063 mol) and anhydrous ethanol (360 ml) were placed in a three-necked flask with a palladium catalyst on carbon (1.8 g). The mixture was stirred and heated to 80 °C under nitrogen protection. 20 ml of hydrazine hydrate was slowly added dropwise using a constant-pressure dropping funnel, and the reaction was allowed to proceed for 6 h. After the reaction was complete, the palladium catalyst on carbon was filtered off from the reactants. The filtered product was then poured into a beaker and allowed to stand until 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene precipitated, with a yield of 87%. (The yield here is obtained by the ratio of the actual mass of the diamine monomer obtained to the theoretical mass of the diamine monomer.) 1 H NMR (DMSO-d6, 400MHz) as attached Figure 1 As shown; FT-IR (KBr) as Figure 3 As shown.
[0062] (2) Preparation of polyimides containing bis(trifluoromethyl) and monomethyl side groups and isophenyl structures
[0063] 1.68 g (3.8 mmol) of 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene, 1.178 g (3.8 mmol) of diphenyl ether tetracarboxylic dianhydride, and 18.6 ml of m-cresol were added to a three-necked flask containing a Dean-Stark apparatus. The mixture was heated to 110 °C and stirred until the solid was completely dissolved in the solvent. Six drops of isoquinoline were then added dropwise, and the reaction was continued at 174 °C for 5 h under a nitrogen atmosphere until the reactant became viscous. The viscous reaction product was poured into anhydrous ethanol to precipitate, yielding a white solid product. This solid product was soaked in ethanol for 23 h and then washed with plenty of deionized hot water to remove the solvent from the polymer. Finally, after drying, the polyimide polymer (PI-A) was obtained. Yield: 95%. 1 H NMR (DMSO-d6, 400 MHz) as attached Figure 2 As shown; FT-IR (KBr) as Figure 4 As shown.
[0064] Example 2
[0065] (1) Preparation of aromatic diamine monomers containing bis(trifluoromethyl) and monomethyl side groups and m-phenyl structures
[0066] (a) 2,6-Dihydroxytoluene (9.931 g, 0.08 mol), 2-chloro-5-nitrotrifluorotoluene (36.08 g, 0.16 mol), and anhydrous sodium carbonate (12.71 g, 0.12 mol) were placed in a three-necked flask equipped with a reflux evaporator. 150 mL of DMAc was added to dissolve the solid in the three-necked flask, and the mixture was stirred and heated to 145 °C for 6 h under a nitrogen atmosphere. After the reaction was completed, the product was poured into 500 mL of deionized water to settle for 13 h. The solid was then filtered off and washed with anhydrous ethanol to obtain a crude product, which was dried for 24 h. The dried crude product was then recrystallized from a 1:1 mixture of DMAc and anhydrous ethanol to obtain the dinitro intermediate 2,6-bis(4-nitro-2-trifluoromethylphenoxy)toluene (MPTN) in 87% yield (the yield here is obtained by the ratio of the actual mass of the intermediate compound obtained to the theoretical mass of the intermediate compound).
[0067] (b) The dinitro intermediate (36 g, 0.071 mol) and anhydrous ethanol (360 ml) were placed in a three-necked flask with palladium catalyst on carbon (1.8 g). The mixture was stirred and heated to 80 °C under nitrogen protection. 20 ml of hydrazine hydrate was slowly added dropwise using a constant-pressure dropping funnel, and the reaction was allowed to proceed for 7 h. After the reaction was complete, the palladium catalyst on carbon was filtered off from the reactants. The filtered product was then poured into a beaker and allowed to stand until 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene precipitated, with a yield of 89%. (The yield here is obtained by the ratio of the actual mass of the diamine monomer obtained to the theoretical mass of the diamine monomer.) ¹H NMR (DMSO-d6, 400 MHz) is attached. Figure 1 As shown; FT-IR (KBr) as Figure 3 As shown.
[0068] (2) Preparation of polyimides containing bis(trifluoromethyl) and monomethyl side groups and isophenyl structures
[0069] 1.68 g (3.8 mmol) of 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene, 1.688 g (3.8 mmol) of hexafluoroisopropyltetracarboxylic dianhydride, and 18.6 ml of m-cresol were added to a three-necked flask containing a Dean-Stark apparatus. The mixture was heated to 110 °C and stirred until the solid was completely dissolved in the solvent. Then, 5 drops of isoquinoline were added dropwise, and the reaction was continued at 174 °C for 7 h under a nitrogen atmosphere until the reactant became viscous. The viscous reaction product was poured into anhydrous ethanol to precipitate and a white solid product was obtained. The solid product was soaked in ethanol for 24 h and then washed with a large amount of deionized hot water to remove the solvent from the polymer. Finally, after drying, the polyimide polymer (PI-B) was obtained. Yield: 94%; ¹H NMR (DMSO-d6, 400 MHz) is shown in the attached image. Figure 2 As shown; FT-IR (KBr) as Figure 4 As shown.
[0070] Example 3
[0071] (1) Preparation of aromatic diamine monomers containing bis(trifluoromethyl) and monomethyl side groups and m-phenyl structures
[0072] (a) 2,6-Dihydroxytoluene (9.31 g, 0.075 mol), 2-chloro-5-nitrotrifluorotoluene (33.83 g, 0.15 mol), and anhydrous sodium carbonate (11.91 g, 0.11 mol) were placed in a three-necked flask equipped with a reflux evaporator. 150 mL of DMAc was added to dissolve the solid in the three-necked flask, and the mixture was stirred and heated to 145 °C for 6 h under a nitrogen atmosphere. After the reaction was completed, the product was poured into 500 mL of deionized water to settle for 14 h. The solid was then filtered off and washed with anhydrous ethanol to obtain a crude product, which was dried for 24 h. The dried crude product was then recrystallized from a 1:1 mixture of DMAc and anhydrous ethanol to obtain the dinitro intermediate 2,6-bis(4-nitro-2-trifluoromethylphenoxy)toluene (MPTN) in 85% yield (the yield here is obtained by the ratio of the actual mass of the intermediate compound obtained to the theoretical mass of the intermediate compound).
[0073] (b) The dinitro intermediate (25.2 g, 0.049 mol) and anhydrous ethanol (360 ml) were placed in a three-necked flask with palladium catalyst on carbon (1.8 g). The mixture was stirred and heated to 82 °C under nitrogen protection. 16 ml of hydrazine hydrate was slowly added dropwise using a constant-pressure dropping funnel, and the reaction was allowed to proceed for 5 h. After the reaction was complete, the palladium catalyst on carbon was filtered off from the reactants. The filtered product was then poured into a beaker and allowed to stand until 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene precipitated, with a yield of 88%. (The yield here is obtained by the ratio of the actual mass of the diamine monomer obtained to the theoretical mass of the diamine monomer.) ¹H NMR (DMSO-d6, 400 MHz) is attached. Figure 1 As shown; FT-IR (KBr) as Figure 3 As shown.
[0074] (2) Preparation of polyimides containing bis(trifluoromethyl) and monomethyl side groups and isophenyl structures
[0075] 1.68 g (3.8 mmol) of 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene, 1.224 g (3.8 mmol) of benzophenone tetracarboxylic dianhydride, and 18.6 ml of m-cresol were added to a three-necked flask containing a Dean-Stark apparatus. The mixture was heated to 110 °C and stirred until the solid was completely dissolved in the solvent. Then, 7 drops of isoquinoline were added dropwise, and the reaction was continued at 174 °C for 7 h under a nitrogen atmosphere until the reactant became viscous. The viscous reaction product was poured into anhydrous ethanol to precipitate and a white solid product was obtained. The solid product was soaked in ethanol for 24 h and then washed with a large amount of deionized hot water to remove the solvent from the polymer. Finally, after drying, the polyimide polymer (PI-C) was obtained. Yield: 92%; 1H NMR (DMSO-d6, 400 MHz) is shown in the attached image. Figure 2 As shown; FT-IR (KBr) as Figure 4 As shown.
[0076] Example 4
[0077] (1) Preparation of aromatic diamine monomers containing bis(trifluoromethyl) and monomethyl side groups and m-phenyl structures
[0078] (a) 2,6-Dihydroxytoluene (8.68 g, 0.07 mol), 2-chloro-5-nitrotrifluorotoluene (31.57 g, 0.14 mol), and anhydrous sodium carbonate (10.59 g, 0.1 mol) were placed in a three-necked flask equipped with a reflux evaporator. 150 mL of DMAc was added to dissolve the solid in the three-necked flask, and the mixture was stirred and heated to 145 °C for 7 h under a nitrogen atmosphere. After the reaction was completed, the product was poured into 500 mL of deionized water to settle for 11 h. The solid was then filtered off and washed with anhydrous ethanol to obtain a crude product, which was dried for 24 h. The dried crude product was then recrystallized from a 1:1 mixture of DMAc and anhydrous ethanol to obtain the dinitro intermediate 2,6-bis(4-nitro-2-trifluoromethylphenoxy)toluene (MPTN) in 91% yield (the yield here is obtained by the ratio of the actual mass of the intermediate compound obtained to the theoretical mass of the intermediate compound).
[0079] (b) The dinitro intermediate (27.72 g, 0.054 mol) and anhydrous ethanol (360 mL) were placed in a three-necked flask with palladium catalyst on carbon (1.8 g). The mixture was stirred and heated to 83 °C under nitrogen protection. 16 mL of hydrazine hydrate was slowly added dropwise using a constant-pressure dropping funnel, and the reaction was allowed to proceed for 7 h. After the reaction was complete, the palladium catalyst on carbon was filtered off from the reactants. The filtered product was then poured into a beaker and allowed to stand until 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene precipitated, with a yield of 86%. (The yield here is obtained by the ratio of the actual mass of the diamine monomer obtained to the theoretical mass of the diamine monomer.) ¹H NMR (DMSO-d6, 400 MHz) is attached. Figure 1 As shown; FT-IR (KBr) as Figure 3 As shown.
[0080] (2) Preparation of polyimides containing bis(trifluoromethyl) and monomethyl side groups and isophenyl structures
[0081] 1.68 g (3.8 mmol) of 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene, 1.977 g (3.8 mmol) of bisphenol A tetracarboxylic dianhydride, and 19.6 ml of m-cresol were added to a three-necked flask containing a Dean-Stark apparatus. The mixture was heated to 110 °C and stirred until the solid was completely dissolved in the solvent. Six drops of isoquinoline were then added dropwise, and the reaction was continued at 174 °C for 6 h under a nitrogen atmosphere until the reactant became viscous. The viscous reaction product was poured into anhydrous ethanol to precipitate, yielding a white solid product. This solid product was soaked in ethanol for 24 h and then washed with plenty of deionized hot water to remove the solvent from the polymer. Finally, after drying, the polyimide polymer (PI-D) was obtained. Yield: 89%; ¹H NMR (DMSO-d6, 400 MHz) is shown in the attached image. Figure 2 As shown; FT-IR (KBr) as Figure 4 As shown.
[0082] Table 1. Intrinsic viscosity and molecular weight of polyimide
[0083]
[0084] Table 1 lists the M values of four polyimides PI-A~D prepared from diamine monomer 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene with diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A tetracarboxylic dianhydride, respectively, in DMAc or dissolved in solvents such as DMF. w M n Values and polydispersity index (PDI).
[0085] Table 2 Solubility properties of polyimide
[0086]
[0087] Note: +++, 0.1 g sample dissolved in 1 mL solvent (10 wt %); ++, soluble at 5 wt %; +, soluble at 1 wt %; +-, swelling; -, insoluble.
[0088] Table 2 shows the solubility of four polyimides PI-A~D prepared from diamine monomer 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene with diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A tetracarboxylic dianhydride, respectively, and commercially available Kapton polyimide films without side groups.
[0089] Table 3 Thermal and mechanical properties of polyimide
[0090]
[0091] Table 3 shows the thermal and mechanical properties of four polyimides PI-A~D prepared from diamine monomer 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene with diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A tetracarboxylic dianhydride, respectively.
[0092] Table 4. Dielectric and optical properties of polyimide
[0093]
[0094] Table 4 shows the dielectric and optical properties of four polyimides PI-A~D prepared from diamine monomer 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene with diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A tetracarboxylic dianhydride, respectively, and commercially available Kapton polyimide films without side groups.
[0095] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A class of aromatic diamine monomers containing a bis(trifluoromethyl) group, a monomethyl side group, and a m-phenylene structure, characterized in that: The aromatic diamine monomer is 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene, and its structural formula is: 。 2. A method for preparing the dinitro intermediate required for the aromatic diamine monomer as described in claim 1, characterized in that: The intermediate is 2,6-bis(4-nitro-2-trifluoromethylphenoxy)toluene; The preparation method is as follows: 2,6-dihydroxytoluene, 2-chloro-5-nitrotrifluorotoluene and alkaline catalyst are mixed in an organic solvent, stirred and heated to 140~150℃ for 4~8h under nitrogen atmosphere protection; after the reaction is completed, the product is poured into deionized water to settle, the solid is filtered out, washed and dried, and the dinitro intermediate 2,6-bis(4-nitro-2-trifluoromethylphenoxy)toluene is collected.
3. A method for preparing an aromatic diamine monomer containing a bis(trifluoromethyl) and monomethyl side group and a m-phenyl structure as described in claim 1, characterized in that: The preparation method is as follows: the dinitro intermediate as described in claim 2, the organic solvent and the catalyst are placed in a reaction vessel, stirred and heated to 80~85°C under nitrogen protection, a reducing agent is added dropwise, and the reaction is carried out for 5~7 hours; after the reaction is completed, the product is allowed to stand and precipitate to obtain the product 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene.
4. A class of polyimides containing bis(trifluoromethyl), monomethyl side groups, and isophenyl structures, characterized in that: The polyimide is polymerized from the aromatic diamine monomer and dianhydride monomer described in claim 1, and its structural formula is: in, for One of them, n=30~100.
5. A method for preparing a polyimide containing a bis(trifluoromethyl), a monomethyl side group, and an isophenyl structure as described in claim 4, characterized in that: Polyimide was prepared by a one-step method: 2,6-bis(4-amino-2-trifluoromethylphenoxy)toluene and dianhydride were added to an organic solvent and stirred at 105-115°C until dissolved. After adding a catalyst, the mixture was heated to 170-180°C under a nitrogen atmosphere and the reaction was continued for 3-8 hours until the reactants became viscous. The viscous reaction product was poured into anhydrous ethanol to precipitate and obtain a solid product. Finally, after drying, the polyimide product was obtained.
6. The method for preparing polyimide containing bis(trifluoromethyl), monomethyl side groups and isophenyl structures as described in claim 5, characterized in that: The dianhydride monomer is one of diphenyl ether tetracarboxylic dianhydride, hexafluoroisopropyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, and bisphenol A tetracarboxylic dianhydride.
7. The method for preparing polyimide containing bis(trifluoromethyl), monomethyl side groups and isophenyl structures as described in claim 5, characterized in that: The organic solvent is m-cresol or N-methylpyrrolidone, and its amount is 7 to 15 times the total mass of the diamine and dianhydride monomers.
8. The method for preparing polyimide containing bis(trifluoromethyl), monomethyl side groups and isophenyl structures as described in claim 5, characterized in that: The catalyst is isoquinoline, and its amount is 1% to 3% of the diamine mass.
9. The application of the polyimide containing bis(trifluoromethyl), monomethyl side groups and isophenyl structures as described in claim 4, characterized in that: The application is for preparing polyimide films; the specific application method is as follows: add the polyimide polymer to an organic solvent to prepare a 5wt%~10wt% solution, filter it, coat it with a film, and dry it at 60~100℃ for 12~24 h to obtain a polyimide film material containing bis(trifluoromethyl), monomethyl side groups and isophenyl structures.