Silicon-based alkyne amine, polyimide and preparation method of silicon-based alkyne amine and polyimide

Abstract

The invention discloses silicon-based alkyne amine, polyimide and a preparation method thereof. The preparation method of the silicon-based alkyne amine monomer comprises the following steps: (1) reacting dichlorosilane containing R1 and R2 structures with ethynyl magnesium bromide in a solvent to obtain a silicon-based diyne compound; and (2) carrying out Sonogashira coupling reaction on the silicon-based diyne compound prepared in the step (1) and an iodo aniline derivative under the action of a palladium catalyst and a copper catalyst to obtain the silicon-based alkyne amine monomer, wherein the iodo-aniline derivative is selected from one of 2-iodine, 3-iodine and 4-iodo-aniline derivatives. The introduction of silicon group and alkynyl can effectively improve the heat resistance and thermal stability of polyimide, and has important application potential in many fields. The method has the advantages that raw materials are easy to obtain, operation is easy, conditions are mild, and the structure can be regulated and controlled.

Description

Technical Field

[0001] The invention belongs to the technical field of synthesis of high-performance polymer materials, and specifically relates to a silicon-based alkynylamine, a polyimide and a preparation method thereof. Background Art

[0002] Polyimide (PI) is widely used in high-end fields such as aerospace, electronics, and automobiles due to its excellent thermal stability, mechanical strength, and chemical resistance. The performance of traditional polyimide materials in high temperature and extreme environments has been fully demonstrated. However, with the continuous increase in industrial demand, the performance requirements for polyimide are also increasing. Especially in harsh environments such as high temperature and strong radiation, the thermal stability, mechanical strength, and corrosion resistance of the material need to be further improved.

[0003] Although traditional polyimide materials have excellent thermal stability, their thermal stability is often limited by certain groups (such as phenyl or amide groups), and long-term exposure to high temperature environments may cause thermal degradation or performance degradation. In addition, while being resistant to high temperatures, the mechanical strength or toughness of the material may be sacrificed. In some applications that require high strength or rigidity and high temperature resistance, the performance of existing polyimide materials may not be sufficient. At the same time, in some special environments (such as contact with strong acids, strong bases or organic solvents), its chemical corrosion resistance may not be ideal, especially in the fields of chemical industry and electronic packaging. The processability of traditional polyimide is relatively poor, especially when high temperature curing is required, which may cause problems such as difficult molding or poor processing accuracy. Summary of the invention

[0004] In order to solve the above problems, the main purpose of the present invention is to provide a silicon-based alkynylamine, which introduces silicon and alkynyl groups to construct a new diamine monomer, which can be polymerized with commercial dianhydride to obtain a polyimide with high temperature resistance.

[0005] Another object of the present invention is to provide a method for preparing the above silicon-based alkynylamine.

[0006] Another object of the present invention is to provide a polyimide comprising the above silicon-based alkynylamine and a preparation method thereof.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] One of the technical solutions of the present invention is a silicon-based alkynylamine monomer, the molecular structure of which is shown in formula (I):

[0009] (I)

[0010] Among them, R 1 and R 2Each of them is selected from hydrogen, C1-C6 alkyl, isopropyl, cyclohexyl, vinyl, propenyl, tert-butyl or phenyl.

[0011] The second technical solution of the present invention is a method for preparing the above-mentioned silicon-based alkynylamine monomer, comprising the following steps:

[0012] (1) The R 1 and R 2 The dichlorosilane of the structure is reacted with ethynylmagnesium bromide in a solvent to obtain a silicon-based diacetylene compound; specifically, under an inert gas atmosphere, 1 and R 2 The dichlorosilane with the structure is dissolved in tetrahydrofuran solution, and ethynylmagnesium bromide solution is slowly added dropwise under ice bath, and the reaction is carried out at room temperature. After the reaction is completed, the quenching and extraction are carried out, and the organic phases are combined, washed, dried and filtered. The filtrate is concentrated under reduced pressure, and the crude product is separated by silica gel column chromatography (eluent is petroleum ether: ethyl acetate = 50 / 1~20 / 1, V / V) to obtain a silicon-based diacetylene compound. Among them, ethynylmagnesium bromide and containing R 1 and R 2 The molar ratio of dichlorosilane in the structure is greater than 2:1.

[0013] (2) The silicon-based diyne compound and the iodoaniline derivative prepared in step (1) are subjected to a Sonogashira coupling reaction under the action of a palladium catalyst and a copper catalyst to obtain the silicon-based alkynylamine monomer; wherein the iodoaniline derivative is selected from one of 2-iodo, 3-iodo or 4-iodoaniline derivatives. The molar ratio of the iodoaniline derivative to the silicon-based diyne compound is greater than 2:1. Specifically, under an inert gas atmosphere, the silicon-based diyne compound, the iodoaniline derivative, the palladium catalyst and the copper catalyst are uniformly mixed in a solvent, and diisopropylamine is slowly added dropwise under an ice bath. After the addition is completed, the reaction is stirred at room temperature for 8 to 14 hours. After the reaction is completed, the reaction is quenched with a saturated ammonium chloride solution, extracted with ethyl acetate, the organic phases are combined, washed with a saturated sodium chloride solution, dried over anhydrous magnesium sulfate and filtered, the filtrate is concentrated under reduced pressure, and the crude product is separated by silica gel column chromatography (the eluent is petroleum ether:ethyl acetate = 40 / 1 to 1.5 / 1, V / V) to obtain the silicon-based alkynylamine monomer.

[0014] Preferably, anhydrous tetrahydrofuran is used as a solvent in step (1), anhydrous tetrahydrofuran is used as a solvent in step (2), the palladium catalyst is bis(triphenylphosphine)palladium dichloride, and the copper catalyst is cuprous iodide.

[0015] The third technical solution of the present invention is a polyimide polymer with high temperature resistance containing the above diamine monomer, the molecular structure of which is shown in formula (II):

[0016] (II)

[0017] Among them, R in formula (II) 1 , R 2 Each of them is selected from one of hydrogen, C1-C6 alkyl, isopropyl, cyclohexyl, vinyl, propenyl, tert-butyl or phenyl, n represents the degree of polymerization, n=5-9, and X is selected from one of the following structures:

[0018] .

[0019] The silicon-based (Si) chemical structure has high-temperature stability and excellent chemical corrosion resistance. Introducing silicon into the polyimide structure can effectively improve the high-temperature resistance and ablation resistance of polyimide. As a highly reactive functional group, the alkynyl group (C≡C) also plays a key enhancing role in the design of polyimide, especially in the cross-linking degree and structural strength of the material. The combination of silicon-alkynyl groups can improve the cross-linking density and structural strength of polyimide. Compared with traditional siloxane groups, alkynyl groups have stronger cross-linking properties. The use of a combination of silicon and alkynyl groups in polyimide not only retains the high-temperature resistance and chemical stability of the silicon group, but also provides additional cross-linking strength through the alkynyl group. This makes the final material have better mechanical properties and heat resistance under extreme conditions.

[0020] A fourth technical solution of the present invention is a method for preparing the above-mentioned polyimide polymer, comprising the following steps:

[0021] (1) in an inert gas atmosphere, dissolving the prepared silicon-based alkynylamine monomer in an organic solvent to obtain a diamine solution, and dissolving the dianhydride monomer in an organic solvent to obtain a dianhydride solution;

[0022] (2) slowly adding the dianhydride solution to the diamine solution for polycondensation reaction, and then adding the end-capping agent 4-phenylethynylphthalic anhydride in batches to obtain a polyamic acid solution;

[0023] (3) Adding a dehydrating agent to the polyamic acid solution to carry out an imidization reaction to obtain a polyimide polymer. Specifically, adding a dehydrating agent to the polyamic acid solution to carry out an imidization reaction, separating water in the imidization process, keeping the temperature for a certain period of time, cooling to room temperature after the imidization reaction is completed, and obtaining a polyimide solution; pouring the polyimide solution into a precipitant, precipitating, filtering and drying to obtain a polyimide polymer.

[0024] The dianhydride monomer used in the preparation method of the above-mentioned polyimide polymer can be selected from the following structures:

[0025] .

[0026] Preferably, the molar ratio of the dianhydride, the diamine and the end-capping agent is n:n+1:2.

[0027] Preferably, the polycondensation reaction is carried out at a temperature of 20-30°C and for a time of 4-24 h.

[0028] Preferably, the mass ratio of the polyamic acid solution to the dehydrating agent is 2-5:1.

[0029] Preferably, the temperature of the imidization reaction is 160-190° C. and the time is 3-8 h.

[0030] Preferably, the end-capping agent may be acetylenic, phenylacetylenic, nadic anhydride, maleic anhydride, trimellitic anhydride, or the like.

[0031] Preferably, the organic solvent is one of N-methyl-2-pyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide.

[0032] Preferably, the dehydrating agent is one of m-xylene or toluene.

[0033] Preferably, the precipitant is methanol or ethanol, that is, the imidized solution is poured into methanol or ethanol to obtain a polyimide precipitate, which is then filtered and dried to obtain a polyimide solid.

[0034] Preferably, the inert gas atmosphere is argon or nitrogen.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The introduction of silicon-based units into diamine monomers can improve the thermal stability of the polymer; the high cross-linking ability of the alkynyl units further improves the stability of polyimide in high temperature environments by forming a dense three-dimensional cross-linked network, reduces thermal degradation and molecular chain breakage at high temperatures, and has better heat resistance.

[0037] (2) The structure of the diamine monomer can be controlled, allowing the preparation of various types of polyimide structures.

[0038] (3) The raw materials of the present invention are easily available, the reaction conditions are mild, and a large amount of polyimide resin can be easily prepared. Moreover, the molecular weight can be regulated by a capping agent, so that polyimide polymers of various specifications can be easily obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a hydrogen nuclear magnetic resonance spectrum of the silicon-based alkynylamine monomer prepared in Example 1 of the present invention;

[0040] Figure 2 This is the carbon NMR spectrum of the silicon-based alkynylamine monomer prepared in Example 1 of the present invention;

[0041] Figure 3 This is a thermal gravimetric curve of the polyimide prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0044] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0045] The experimental methods used in the following specific examples are all conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples are all commercially available unless otherwise specified.

[0046] Example 1

[0047] This example prepares a silicon-based alkynylamine monomer.

[0048] Diphenyldichlorosilane and ethynylmagnesium bromide are reacted by Grignard reaction to obtain diethynyldiphenylsilane, which is further reacted with p-iodoaniline by Sonogashira coupling reaction to obtain diphenylsilyl alkynylamine monomer, as follows:

[0049] Take a dry 100 mL round-bottom flask, dissolve diphenyldichlorosilane (10 mmol) in anhydrous tetrahydrofuran (10 mL) under argon atmosphere, slowly add ethynylmagnesium bromide solution (21 mmol, 2.1 equiv) dropwise under ice bath, react at room temperature for 12 h, quench with saturated ammonium chloride solution after the reaction, extract with ethyl acetate, combine the organic phases, wash with saturated sodium chloride solution, dry with anhydrous magnesium sulfate, and filter. The filtrate is concentrated under reduced pressure, and the crude product is separated by silica gel column chromatography (eluent is petroleum ether: ethyl acetate = 50 / 1~20 / 1, V / V) to obtain diethynyldiphenylsilane.

[0050] 1 H NMR (400 MHz, DMSO) δ 7.67–7.64 (m, 4H), 7.52–7.44 (m, 6H), 3.98 (s, 2H).

[0051] Take a dry 100 mL round-bottom flask, add diethynyldiphenylsilane (5.0 mmol, 1.0 equiv), p-iodoaniline (10.5 mmol, 2.1 equiv), bis(triphenylphosphine)palladium dichloride (0.2 mmol, 4 mol%), cuprous iodide (0.2 mmol, 4 mol%) and anhydrous tetrahydrofuran (25 mL, 0.2 M) in sequence under argon atmosphere, and slowly add diisopropylamine (20.0 mmol, 4.0 equiv) dropwise under ice bath. After the addition is completed, the reaction is stirred at room temperature for 12 h (TLC monitors the reaction). After the reaction is completed, saturated ammonium chloride solution is quenched, ethyl acetate is extracted, the organic phases are combined, washed with saturated sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and the filtrate is concentrated under reduced pressure. The crude product is separated by silica gel column chromatography (eluent is petroleum ether: ethyl acetate = 40 / 1~1.5 / 1, V / V) to obtain diphenylsilyl alkynylamine monomer.

[0052] The above target products were characterized, such as Figure 1 and 2 shown.

[0053] 1 H NMR (400 MHz, DMSO) δ 7.75–7.74 (m, 4H), 7.48-7.43 (m, 6H), 7.26 (d, J = 8.5 Hz, 4H), 6.54 (d, J = 8.5 Hz, 4H), 5.72 (s, 4H); 13 C NMR (100 MHz, DMSO) δ 150.9, 134.8, 134.1, 133.9, 130.7, 128.7, 113.9, 111.7, 107.3, 84.4.

[0054] Example 2

[0055] This example prepares a silicon-based alkynylamine monomer.

[0056] Dichloromethylphenylsilane and ethynylmagnesium bromide are reacted by Grignard reaction to obtain diethynylmethylphenylsilane, which is further reacted with p-iodoaniline by Sonogashira coupling reaction to obtain methylphenylsilyl alkynylamine monomer, as follows:

[0057] Take a dry 100 mL round-bottom flask, dissolve dichloromethylphenylsilane (10 mmol) in anhydrous tetrahydrofuran (10 mL) under argon atmosphere, slowly add ethynylmagnesium bromide solution (21 mmol, 2.1 equiv) dropwise under ice bath, react at room temperature for 12 h, quench with saturated ammonium chloride solution after the reaction, extract with ethyl acetate, combine the organic phases, wash with saturated sodium chloride solution, dry over anhydrous magnesium sulfate and filter, concentrate the filtrate under reduced pressure, and separate the crude product by silica gel column chromatography (eluent is petroleum ether: ethyl acetate = 100 / 1~50 / 1, V / V) to obtain diethynylmethylphenylsilane.

[0058] 1 H NMR (400 MHz, DMSO) δ 7.70–7.62 (m, 2H), 7.52–7.39 (m, 3H), 3.75 (s, 2H), 0.54 (s, 3H).

[0059] Take a dry 100 mL round-bottom flask, add diethynylmethylphenylsilane (5.0 mmol, 1.0 equiv), p-iodoaniline (10.5 mmol, 2.1 equiv), bis(triphenylphosphine)palladium dichloride (0.2 mmol, 4 mol %), cuprous iodide (0.2 mmol, 4 mol %) and anhydrous tetrahydrofuran (25 mL, 0.2 M) in sequence under argon atmosphere, and slowly add diisopropylamine (20.0 mmol, 4.0 equiv) dropwise under ice bath. After the addition is completed, the reaction is stirred at room temperature for 12 h (TLC monitors the reaction). After the reaction is completed, saturated ammonium chloride solution is quenched, ethyl acetate is extracted, the organic phases are combined, washed with saturated sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and the filtrate is concentrated under reduced pressure. The crude product is separated by silica gel column chromatography (eluent is petroleum ether:ethyl acetate = 40 / 1~1.5 / 1, V / V) to obtain methylphenylsilyl alkynylamine monomer.

[0060] The above target products were characterized.

[0061] 1 H NMR (400 MHz, DMSO) δ 7.76–7.74 (m, 2H), 7.53–7.38 (m, 3H), 7.19 (d, J = 8.4 Hz, 4H), 6.52 (d, J = 8.5 Hz, 4H), 5.66 (s, 4H), 0.58 (s, 3H); 13CNMR (100 MHz, DMSO) δ 150.7, 135.2, 134.3, 133.7, 130.5, 128.6, 113.9, 110.1,107.7, 86.2, 0.9.

[0062] Example 3

[0063] This example prepares a polyimide polymer.

[0064] Under argon atmosphere, the diphenylsilyl alkynylamine monomer (0.83 g, 2.0 mmol) and the dianhydride monomer 6FDA (0.74 g, 1.67 mmol) prepared in Example 1 were dissolved in 6 mL of anhydrous N,N-dimethylacetamide (DMAc) respectively. After complete dissolution, the dianhydride solution was slowly added dropwise to the diamine solution and stirred at room temperature for 5 h. Subsequently, the end-capping agent 4-phenylethynylphthalic anhydride (0.17 g, 0.67 mmol) was added in batches, and DMAc was added to a solid content of 10%, and then stirred at room temperature for 12 h to obtain a homogeneous, viscous polyimide acid solution. The dehydrating agent m-xylene was added thereto and heated at 190 o C, separate the water in the imidization process through a water separator, and keep warm for 3 hours. After the reaction is completed, cool to room temperature, pour the obtained polyimide solution into methanol, and a precipitate is precipitated, which is filtered and vacuum dried to obtain a yellowish brown solid.

[0065] The dianhydride monomers used in this embodiment and the following embodiments were all purchased from Anaiji.

[0066] Thermogravimetric curve Figure 3 As shown. Figure 3 It can be concluded that the 5% thermal weight loss temperature of the polymer is 520°C, indicating that it has better heat resistance.

[0067] The molecular structure of the polyimide in this embodiment is as follows:

[0068]

[0069] Example 4

[0070] This example prepares a polyimide polymer.

[0071] Under argon atmosphere, the methylphenylsilyl alkynylamine monomer (0.71 g, 2.0 mmol) and dianhydride 6FDA (0.74 g, 1.67 mmol) prepared in Example 2 were dissolved in 6 mL of anhydrous N,N-dimethylacetamide (DMAc) respectively. After complete dissolution, the dianhydride solution was slowly added dropwise to the diamine solution and stirred at room temperature for 5 h. Subsequently, the end-capping agent 4-phenylethynylphthalic anhydride (0.17 g, 0.67 mmol) was added in batches, and DMAc was added to a solid content of 10%, and then stirred at room temperature for 12 h to obtain a homogeneous, viscous polyimide acid solution. The dehydrating agent m-xylene was added thereto and heated at 190 o C, separate the water in the imidization process through a water separator, and keep warm for 3 hours. After the reaction is completed, cool to room temperature, pour the obtained polyimide solution into methanol, and precipitate is precipitated, which is filtered and vacuum dried to obtain a brown solid.

[0072] The molecular structure of the polyimide in this embodiment is as follows:

[0073]

[0074] Example 5

[0075] This example prepares a polyimide polymer.

[0076] Under argon atmosphere, the diphenylsilyl alkynylamine monomer (0.83 g, 2.0 mmol) and 4,4'-oxydiphthalic anhydride (0.52 g, 1.67 mmol) prepared in Example 1 were dissolved in 6 mL of anhydrous N,N-dimethylacetamide (DMAc) respectively. After complete dissolution, the dianhydride solution was slowly added dropwise to the diamine solution and stirred at room temperature for 5 h. Subsequently, the end-capping agent 4-phenylethynylphthalic anhydride (0.17 g, 0.67 mmol) was added in batches, and DMAc was added to a solid content of 10%, and then stirred at room temperature for 12 h to obtain a homogeneous, viscous polyimide acid solution. The dehydrating agent m-xylene was added thereto and heated at 190 o C, separate the water in the imidization process through a water separator, and keep warm for 3 hours. After the reaction is completed, cool to room temperature, pour the obtained polyimide solution into methanol, and a precipitate is precipitated, which is filtered and vacuum dried to obtain a yellowish brown solid.

[0077] The molecular structure of the polyimide in this embodiment is as follows:

[0078]

[0079] Example 6

[0080] This example prepares a polyimide polymer.

[0081] Under argon atmosphere, the diphenylsilyl alkynylamine monomer (0.83 g, 2.0 mmol) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (0.54 g, 1.67 mmol) prepared in Example 1 were dissolved in 6 mL of anhydrous N,N-dimethylacetamide (DMAc) respectively. After complete dissolution, the dianhydride solution was slowly added dropwise to the diamine solution and stirred at room temperature for 5 h. Subsequently, the end-capping agent 4-phenylethynylphthalic anhydride (0.17 g, 0.67 mmol) was added in batches, and DMAc was added to a solid content of 10%, and then stirred at room temperature for 12 h to obtain a homogeneous, viscous polyimide acid solution. The dehydrating agent m-xylene was added thereto and heated at 190 o C, separate the water in the imidization process through a water separator, and keep warm for 3 hours. After the reaction is completed, cool to room temperature, pour the obtained polyimide solution into methanol, and a precipitate is precipitated, which is filtered and vacuum dried to obtain a yellowish brown solid.

[0082] The molecular structure of the polyimide in this embodiment is as follows:

[0083]

[0084] Example 7

[0085] This example prepares a polyimide polymer.

[0086] Under argon atmosphere, the methylphenylsilyl alkynylamine monomer (0.71 g, 2.0 mmol) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (0.54 g, 1.67 mmol) prepared in Example 2 were dissolved in 6 mL of anhydrous N,N-dimethylacetamide (DMAc) respectively. After complete dissolution, the dianhydride solution was slowly added dropwise to the diamine solution and stirred at room temperature for 5 h. Subsequently, the end-capping agent 4-phenylethynylphthalic anhydride (0.17 g, 0.67 mmol) was added in batches, and DMAc was added to a solid content of 10%, and then stirred at room temperature for 12 h to obtain a homogeneous, viscous polyimide acid solution. The dehydrating agent m-xylene was added thereto and heated at 190 o C, separate the water in the imidization process through a water separator, and keep warm for 3 hours. After the reaction is completed, cool to room temperature, pour the obtained polyimide solution into methanol, and a precipitate is precipitated, which is filtered and vacuum dried to obtain a yellowish brown solid.

[0087] The molecular structure of the polyimide in this embodiment is as follows:

[0088]

[0089] Example 8

[0090] This example prepares a polyimide polymer.

[0091] Under argon atmosphere, the diphenylsilyl alkynylamine monomer (0.83 g, 2.0 mmol) and the dianhydride monomer 6FDA (0.78 g, 1.75 mmol) prepared in Example 1 were dissolved in 6 mL of anhydrous N,N-dimethylacetamide (DMAc) respectively. After complete dissolution, the dianhydride solution was slowly added dropwise to the diamine solution and stirred at room temperature for 5 h. Subsequently, the end-capping agent 4-phenylethynylphthalic anhydride (0.12 g, 0.5 mmol) was added in batches, and DMAc was added to a solid content of 10%, and then stirred at room temperature for 12 h to obtain a homogeneous, viscous polyimide acid solution. The dehydrating agent m-xylene was added thereto and heated at 190 o C, separate the water in the imidization process through a water separator, and keep warm for 3 hours. After the reaction is completed, cool to room temperature, pour the obtained polyimide solution into methanol, and precipitate is precipitated, which is filtered and vacuum dried to obtain a brown solid.

[0092] The molecular structure of the polyimide in this embodiment is as follows:

[0093]

[0094] Example 9

[0095] This example prepares a polyimide polymer.

[0096] Under argon atmosphere, the diphenylsilyl alkynylamine monomer (0.83 g, 2.0 mmol) and the dianhydride monomer 6FDA (0.80 g, 1.8 mmol) prepared in Example 1 were dissolved in 6 mL of anhydrous N,N-dimethylacetamide (DMAc) respectively. After complete dissolution, the dianhydride solution was slowly added dropwise to the diamine solution and stirred at room temperature for 5 h. Subsequently, the end-capping agent 4-phenylethynylphthalic anhydride (0.10 g, 0.4 mmol) was added in batches, and DMAc was added to a solid content of 10%, and then stirred at room temperature for 12 h to obtain a homogeneous, viscous polyimide acid solution. The dehydrating agent m-xylene was added thereto and heated at 190 o C, separate the water in the imidization process through a water separator, and keep warm for 3 hours. After the reaction is completed, cool to room temperature, pour the obtained polyimide solution into methanol, and precipitate is precipitated, which is filtered and vacuum dried to obtain a brown solid.

[0097] The molecular structure of the polyimide in this embodiment is as follows:

[0098]

[0099] The present invention uses diethynylsilane as a raw material to provide a novel silicon-based alkynylamine skeleton compound, which can act together with commercial dianhydride to prepare high-temperature resistant polyimide polymers of various molecular weights under the action of a capping agent. The method of the present invention has the advantages of easy raw material availability, simple operation, mild conditions, and adjustable structure.

[0100] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A silicon-based alkynylamine monomer, characterized in that The general molecular structure is shown in formula (I): （I）； Among them, R 1 and R 2 Each of them is selected from hydrogen, C1-C6 alkyl, isopropyl, cyclohexyl, vinyl, propenyl, tert-butyl or phenyl.

2. A method for preparing the silicon-based alkynylamine monomer according to claim 1, characterized in that: The following steps are involved: (1) The R 1 and R 2 The dichlorosilane of the structure reacts with ethynylmagnesium bromide in a solvent to obtain a silicon-based diyne compound; (2) The silicon-based diyne compound and the iodoaniline derivative prepared in step (1) are subjected to a Sonogashira coupling reaction in the presence of a palladium catalyst and a copper catalyst to obtain the silicon-based alkynylamine monomer; wherein the iodoaniline derivative is selected from one of 2-iodo, 3-iodo or 4-iodoaniline derivatives.

3. A polyimide polymer, characterized in that: The molecular structure is shown in formula (II): (II); Among them, R in formula (II) 1 and R 2 are selected from one of hydrogen, C1-C6 alkyl, isopropyl, cyclohexyl, vinyl, propenyl, tert-butyl or phenyl; n represents the degree of polymerization, n=5-9; X is selected from one of the following structures: 。 4. A method for preparing a polyimide polymer according to claim 3, characterized in that: The following steps are involved: (1) in an inert gas atmosphere, dissolving the prepared silicon-based alkynylamine monomer in an organic solvent to obtain a diamine solution, and dissolving the dianhydride monomer in an organic solvent to obtain a dianhydride solution; (2) slowly adding the dianhydride solution to the diamine solution for polycondensation reaction, and then adding the end-capping agent in batches to obtain a polyamic acid solution; (3) Adding a dehydrating agent to the polyamic acid solution to carry out an imidization reaction to obtain a polyimide polymer.

5. The method for preparing a polyimide polymer according to claim 4, characterized in that: The molar ratio of the dianhydride monomer, the silicon-based alkynylamine monomer and the end-capping agent is n:n+1:

2.

6. The method for preparing a polyimide polymer according to claim 4, characterized in that: The temperature of the polycondensation reaction is 20-30° C. and the time is 4-24 h.

7. The method for preparing a polyimide polymer according to claim 4, characterized in that: The temperature of the imidization reaction is 160-190° C. and the time is 3-8 h.

8. The method for preparing a polyimide polymer according to claim 4, characterized in that: The mass ratio of the polyamic acid solution to the dehydrating agent is 2-5:

1.

9. The method for preparing a polyimide polymer according to claim 4, characterized in that: The dehydrating agent is one of m-xylene or toluene.

10. The method for preparing a polyimide polymer according to claim 4, characterized in that: The organic solvent is one of N-methyl-2-pyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide.

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