A polynorbornene imide insulating material, its preparation method and application

Abstract

This invention discloses a polynorbornene imide insulating material, its preparation method, and its applications, belonging to the technical field of electrical insulation materials and their preparation. This invention solves the problem of poor insulation performance in existing polynorbornene imide dielectric films. This invention obtains FPNI by fluorinating polynorbornene imide (PNI), a polymer dielectric film with a wide bandgap and a high glass transition temperature organic rigid backbone. Furthermore, by doping FPNI with the wide bandgap organic molecule 4,4-dihydroxydicyclohexane (OH), not only is hydrogen bonding crosslinking between hydroxyl and fluorine atoms achieved, but the wide bandgap OH also brings higher electronic transition energy levels, resulting in a crosslinked polymer film with excellent insulation performance and a breakdown field strength of 619.53 MV / m.

Description

Technical Field

[0001] This invention relates to a polynorbornene imide insulating material, its preparation method, and its application, belonging to the technical field of electrical insulation materials and their preparation. Background Technology

[0002] During long-term operation, factors such as aging, moisture, mechanical damage, excessive voltage, or temperature rise can cause the insulation material between motor windings to lose its original insulating properties, potentially leading to unstable operation or even malfunctions in electrical equipment. Therefore, as electrical equipment develops towards higher voltage, higher power, and higher efficiency, the requirements for winding insulation materials are becoming increasingly stringent. Traditional winding insulation materials, such as fiber paper and epoxy resins, are widely used due to their low cost and high mechanical strength. However, modern power and motor equipment places higher demands on the performance of winding insulation materials, making the development of a winding insulation material with excellent electrical insulation stability a current research focus.

[0003] Polynorbornene imide-based materials have gradually become a research hotspot for novel winding insulation materials due to their excellent high-temperature resistance and high-field properties. However, due to softening and aging at high temperatures, the electrical properties of polynorbornene imide-based materials gradually decline during long-term use. Therefore, it is essential to further improve the insulation performance of polynorbornene imide dielectric films, providing a more superior material choice for winding insulation of power equipment. Summary of the Invention

[0004] This invention addresses the problem of poor insulation performance of existing polynorbornene imide dielectric films by providing a polynorbornene imide insulating material, its preparation method, and its applications.

[0005] The technical solution of the present invention:

[0006] One objective of this invention is to provide a method for preparing polynorbornene imide insulating material, the method comprising the following steps:

[0007] (i) The monomer N-(phenyl)norbornadiene diamide is generated by amidation reaction with norbornadiene anhydride and aniline, named NI; the monomer N-(pentafluorophenyl)norbornadiene diamide is generated by amidation reaction with norbornadiene anhydride and pentafluoroaniline, named FNI.

[0008] (ii) Using NI and / or FNI as raw materials, a ring-opening metathesis polymerization reaction is carried out to obtain polynorbornene imide insulating material.

[0009] Further specifying, the operation process of (i) is as follows:

[0010] (1) Dissolve norborneol in glacial acetic acid solution to obtain solution A;

[0011] (2) Add aniline or pentafluoroaniline to solution A and stir until homogeneous to obtain solution B;

[0012] (3) Add the catalyst to solution B, heat and stir at 120°C for 24 hours to obtain solution C;

[0013] (4) After solution C is cooled to room temperature, deionized water is added, and the solution is filtered under vacuum to obtain a white solid. After washing, the solid is purified by column chromatography and dried to obtain NI or FNI.

[0014] Further specifying, the molar ratio of norbornene to aniline or pentafluoroaniline is 1:1.2.

[0015] Further specifying, the catalyst is 4-dimethylaminopyridine.

[0016] Further specified, the mass ratio of norbornene olefinic anhydride to aniline or pentafluoroaniline is 2.46:0.585.

[0017] Further specified, the mass-to-volume ratio of norbornene and glacial acetic acid in solution A of (1) is 2.46 g: 25 mL.

[0018] Further specifying, the mobile phase in column chromatography is prepared by mixing ethyl acetate and n-hexane in a ratio of 1:5.

[0019] Further specifying, the operation process of (ii) is as follows:

[0020] Step 1: Under a dry nitrogen atmosphere, dissolve NI and FNI in an ultra-dry dichloromethane solution to obtain solution D;

[0021] Step 2: Under a dry nitrogen atmosphere, dissolve the Grubbs II catalyst in an ultra-dry dichloromethane solution to obtain solution E;

[0022] Step 3: Under a dry nitrogen atmosphere, mix solutions D and E, stir at room temperature until the reaction is complete, add the stopping agent vinyl ether, and continue stirring for 30-40 minutes.

[0023] Step four: The reacted solution is added dropwise to a methanol solution to obtain a solid product. The solid product is then subjected to Soxhlet extraction for 48 hours using methanol as the solution. Finally, it is vacuum dried at 60-65℃ for 48 hours to obtain polynorbornene imide insulating material.

[0024] Further specified, the molar percentage of NI in the mixed monomers NI and FNI is 0%, 25%, 50%, 75% or 100%.

[0025] The second objective of this invention is to provide a polynorbornene imide insulating material prepared by the above method.

[0026] The third objective of this invention is to provide an application of the above-mentioned polynorbornene imide insulating material, specifically for the preparation of polynorbornene imide insulating films.

[0027] Further specifying the preparation method, the method is as follows: dissolve the polynorbornene imide insulating material in an ultra-dry dichloromethane solution, then form a film on a glass plate by solution casting, obtain a wet film, dry the wet film to obtain a dry film, and perform vacuum drying treatment on the dry film to obtain a polynorbornene imide insulating film.

[0028] Further specifying, the mass fraction of the polymer in the casting solution is 5%.

[0029] Further specified, the drying temperature is 60-65℃, and the time is 2-4 hours.

[0030] Further specify the vacuum drying conditions as follows: drying at 60-65℃ under vacuum for 24 hours.

[0031] Further, the thickness of the obtained polynorbornene imide film is 5-8 μm.

[0032] The fourth objective of this invention is to provide an application of the above-mentioned polynorbornene imide insulating material, specifically for the preparation of a wide-gap all-organic insulating film for winding insulation.

[0033] Further specifying the preparation method, the method is as follows: polynorbornene imide insulating material and 4,4-dihydroxydicyclohexane are dissolved in an ultra-dry dichloromethane solution, and then a film is formed on a glass plate by solution casting. The wet film is dried to obtain a dry film, and the dry film is subjected to vacuum drying treatment to obtain a wide-gap all-organic insulating film for winding insulation.

[0034] Further specified, the mass ratio of polynorbornene imide insulation material to 4,4-dihydroxydicyclohexane is 0.1:(0.0001-0.001).

[0035] Furthermore, the mass fraction of the casting solution is 5%.

[0036] Further specified, the drying temperature is 60-65℃, and the time is 2-4 hours.

[0037] Further specify the vacuum drying conditions as follows: drying at 60-65℃ under vacuum for 24 hours.

[0038] Further, the thickness of the obtained polynorbornene imide film is 5-8 μm.

[0039] The fifth objective of this invention is to provide an application of the insulating film prepared by the above method, specifically as an insulating medium in the preparation of electrical insulating devices.

[0040] To further define, electrical insulation devices include smart grids, new energy vehicles, and AC / DC power transmission networks.

[0041] Beneficial effects:

[0042] This invention obtains FPNI by fluorinating polynorborneneimide (PNI), a polymer dielectric film with a wide bandgap and a high glass transition temperature organic rigid backbone. Furthermore, by doping FPNI with the wide bandgap organic molecule 4,4-dihydroxydicyclohexane (OH), not only is hydrogen bonding between hydroxyl and fluorine atoms achieved, but the wide bandgap OH also introduces higher electronic transition energy levels, resulting in a cross-linked polymer film with excellent insulating properties and a breakdown field strength of 619.53 MV / m. Compared with existing technologies, this invention has at least the following advantages:

[0043] (1) The present invention improves the breakdown field strength of polymer by fluorinating norborneneimide and enhancing the electronegativity of polymer by introducing fluorine atoms, thereby increasing the polymer’s electron-withdrawing ability and trap depth.

[0044] (2) The present invention further improves the insulation properties of the material by doping with aliphatic ring hydroxyl (OH) with a wider band gap. Specifically, hydrogen atoms in the hydroxyl group form hydrogen bonds with fluorine atoms in the polymer FPNI. The formation of hydrogen bonds not only enhances the interaction between materials, but also constructs a network cross-linked structure, effectively reducing dielectric loss and improving the breakdown strength of the dielectric material, so that the material can withstand a larger voltage under high electric field conditions without insulation failure.

[0045] (3) The synthesis process of the insulating material provided by this invention is simple, and it has mature large-scale preparation technology. Existing industrial equipment can meet the production needs. It can also maintain the flexibility and uniformity of polymer materials, effectively solving the problems of agglomeration and mechanical property deterioration caused by doping modification, as well as various challenges faced by industrialization such as the mismatch of polymer matrix molding technology. It provides a guiding idea for the large-scale preparation of all-organic dielectric films for winding insulation. Attached Figure Description

[0046] Figure 1 The 1H NMR spectrum of NI prepared in Comparative Example 1;

[0047] Figure 2 The 1H NMR spectrum of the FNI prepared in Example 4;

[0048] Figure 3 FPNI prepared for Examples 1-4 and Comparative Example 10.25 FPNI 0.5 FPNI 0.75 Fourier transform infrared images of FPNI1 and PNI;

[0049] Figure 4 FPNI prepared for Examples 2 and 5-7 0.5 and FPNI 0.5 -OH 0.1% FPNI 0.5 -OH 0.3% FPNI 0.5 -OH 1% Fourier infrared images of [the data] and [the data].

[0050] Figure 5 FPNI prepared for Examples 1-4 and Comparative Example 1 0.25 FPNI 0.5 FPNI 0.75 XRD patterns of FPNI1 and PNI;

[0051] Figure 6 Band structures of PNI prepared in Comparative Example 1, FPNI1 prepared in Example 4, and 4,4-dihydroxydicyclohexane.

[0052] Figure 7 FPNI prepared for Examples 1-4 and Comparative Example 1 0.25 FPNI 0.5 FPNI 0.75 Dielectric spectra of FPNI1 and PNI;

[0053] Figure 8 FPNI prepared for Examples 2 and 5-7 0.5 and FPNI 0.5 -OH 0.1% FPNI 0.5 -OH 0.3% FPNI 0.5 -OH 1% The dielectric spectrum;

[0054] Figure 9 FPNI prepared for Examples 1-4 and Comparative Example 1 0.25 FPNI 0.5 FPNI 0.75 Conductivity diagrams of FPNI1 and PNI;

[0055] Figure 10 FPNI prepared for Examples 2 and 5-7 0.5 and FPNI 0.5 -OH 0.1% FPNI 0.5-OH 0.3% FPNI 0.5 -OH 1% Conductivity diagram;

[0056] Figure 11 FPNI prepared for Examples 1-4 and Comparative Example 1 0.25 FPNI 0.5 FPNI 0.75 Comparison of breakdown characteristics of FPNI1 and PNI at room temperature;

[0057] Figure 12 FPNI prepared for Examples 2 and 5-7 0.5 and FPNI 0.5 -OH 0.1% FPNI 0.5 -OH 0.3% FPNI 0.5 -OH 1% Comparison of breakdown characteristics at room temperature. Detailed Implementation

[0058] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0059] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0060] 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 phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0061] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, all materials, reagents, methods, and instruments used are conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art. Furthermore, all solid and liquid reagents used are of analytical grade.

[0062] Example 1

[0063] Step 1: Prepare two portions of solution A for later use; the specific preparation method for each portion is as follows: weigh 2.46g of norborneol enediic anhydride and dissolve it in 25ml of glacial acetic acid at room temperature to obtain solution A;

[0064] Step 2: Weigh 0.585g of 4-dimethylaminopyridine (DMAP) and dissolve it in a 1.51g aniline solution to obtain solution B;

[0065] Step 3: Mix one portion of solution A and one portion of solution B and place them in an Erlenmeyer flask that has been purged with dry nitrogen. Reflux and heat with magnetic stirring at 120°C. Monitor the reaction using thin-layer chromatography (the developing solvent is prepared by mixing ethyl acetate and n-hexane in a volume ratio of 1:5) until the reaction is complete.

[0066] Step 4: Cool the refluxed and completely reacted mixed solution to room temperature, pour in a large amount of deionized water to produce a white precipitate, filter it, wash and filter the precipitate several times, and make the washing solution neutral.

[0067] Step 5: Purify and dry the product using column chromatography to obtain monomer NI (the mobile phase is prepared by mixing ethyl acetate and n-hexane in a volume ratio of 1:5).

[0068] Step 6: Dissolve 0.585g of 4-dimethylaminopyridine (DMAP) in a solution of 2.96g of pentafluoroaniline to obtain solution C;

[0069] Step 7: Mix another portion of solution A and solution C and place them in an Erlenmeyer flask purged with dry nitrogen. Reflux and heat with magnetic stirring at 120°C. Monitor the reaction using thin-layer chromatography (the developing solvent is prepared by mixing ethyl acetate and n-hexane in a volume ratio of 1:5) until the reaction is complete.

[0070] Step 8: Cool the refluxed and completely reacted mixed solution to room temperature, pour in a large amount of deionized water to produce a white precipitate, filter it, wash and filter the precipitate several times, and make the washing solution neutral.

[0071] Step 9: Purify and dry the product using column chromatography to obtain monomer FNI (the mobile phase is prepared by mixing ethyl acetate and n-hexane in a volume ratio of 1:5).

[0072] Step 10: Weigh 0.502g of monomer NI and 2.073g of monomer FNI and place them into a Shrek tube that has been treated with anhydrous and oxygen-free conditions and insert a PTFE tee. Then, inject 20ml of ultra-dry dichloromethane into the Shrek tube under nitrogen protection.

[0073] Step 11: Dissolve 17.8 mg of Grubbs II catalyst in another 2 ml Shrek tube containing ultra-dry dichloromethane to obtain solution D;

[0074] Step 12: Transfer solution D to the mixed monomer solution, stir at room temperature, and monitor the degree of reaction using thin-layer chromatography (the developing solvent is prepared by ethyl acetate and n-hexane in a volume ratio of 1:5) until the reaction is complete;

[0075] Step 13: After the reaction is complete, add 1 ml of vinyl ether to terminate the reaction, and continue stirring for 30 minutes at a speed of 450 r / min;

[0076] Step Fourteen: The solution is uniformly added dropwise to the methanol solution to produce a precipitate. The precipitate is washed with a Soxhlet extractor and placed in a vacuum oven to dry at 60°C for 48 hours to obtain the polymer FPNI. 0.25 ;

[0077] Step 15: Dry the polymer FPNI 0.25 A 5 wt% precursor solution was prepared with dichloromethane, filtered, and stirred at room temperature for 2 hours.

[0078] Step 16: A wet film is obtained by solution casting onto a glass plate. The wet film is dried at 60°C for 2 hours to obtain a dry film. The dry film is then vacuum dried at 60°C for 24 hours to obtain an FPNI film with a thickness of 5 μm. 0.25 film.

[0079] Example 2

[0080] The difference between this embodiment and Embodiment 1 is that in step ten, the monomer NI is 1g and the monomer FNI is 1.38g. The remaining process steps and parameter settings are the same as in Embodiment 1, resulting in polymer FPNI. 0.5 and FPNI with a thickness of 5μm 0.5 film.

[0081] Example 3

[0082] The difference between this embodiment and Embodiment 1 is that in step ten, the monomer NI is 1.51g and the monomer FNI is 0.7g. The remaining process steps and parameter settings are the same as in Embodiment 1, yielding the polymer FPNI. 0.75 and FPNI with a thickness of 5μm 0.75 film.

[0083] Example 4

[0084] The difference between this embodiment and Embodiment 1 is that in step ten, the monomer NI is 0g and the monomer FNI is 2.764g. The remaining process steps and parameter settings are the same as in Embodiment 1, resulting in polymer FPNI1 and an FPNI1 film with a thickness of 5μm.

[0085] Comparative Example 1

[0086] The difference between this comparative example and Example 1 is that in step ten, the monomer NI is 2g and the monomer FNI is 0g. The remaining process steps and parameter settings are the same as in Example 1, resulting in polymer FPNI1 and a PNI film with a thickness of 5μm.

[0087] Example 1

[0088] The FPNI and PNI prepared in Examples 1-4 and Comparative Example 1 were characterized, and the specific detection and results are as follows:

[0089] (1) The 1H NMR spectrum of the monomer NI prepared in Comparative Example 1 is as follows: Figure 1 As shown, by Figure 1 It can be seen that the peaks of the two hydrogens of the amino group on aniline have disappeared in the 1H NMR spectrum, and have been replaced by the 1H NMR distribution of norbornyl anhydride. Furthermore, the integrated areas of the characteristic peaks in the 1H NMR spectrum of the monomer correspond one-to-one with the number of hydrogens in the target synthesis, proving that the NI monomer has been successfully synthesized.

[0090] (2) The 1H NMR spectrum of the monomer FNI prepared in Example 4 is as follows: Figure 2 As shown, by Figure 2 It can be seen that the peaks of the two hydrogens of the amino group on pentafluoroaniline have disappeared in the 1H NMR spectrum, and have been replaced by the 1H NMR distribution of norbornene enediic anhydride. Furthermore, the integrated areas of the characteristic peaks in the monomer's 1H NMR spectrum correspond one-to-one with the number of hydrogens in the target synthesis, proving that the FNI monomer has been successfully synthesized.

[0091] (3) Figure 3 FPNI prepared for Examples 1-4 and Comparative Example 1 0.25 FPNI 0.5 FPNI 0.75 Fourier transform infrared images of FPNI1 and PNI, by Figure 3 It can be seen that the wavelength of the CF bond in the infrared spectrum is approximately in the range of 1050-1350 cm⁻¹. -1 The comparison shows that at 1136.6 cm⁻¹ in the infrared spectrum... -1 At this point, the peak intensity increases with the increase of fluorination ratio, thus proving that the successful synthesis of the polymer is due to the successful introduction of the monomer FNI.

[0092] (4) Figure 5 FPNI prepared for Examples 1-4 and Comparative Example 1 0.25 FPNI 0.5 FPNI 0.75 XRD patterns of FPNI1 and PNI, by Figure 5 It can be seen that the polymer modification schemes are fluorination and the introduction of organic compounds, and no characteristic peaks are observed in the XRD, thus meeting the expected target.

[0093] (5) Figure 7 FPNI prepared for Examples 1-4 and Comparative Example 1 0.25 FPNI 0.5 FPNI 0.75 The dielectric spectrum diagrams of FPNI1 and PNI are obtained from... Figure 7 It can be seen that the dielectric loss remains at a relatively low value, but the dielectric constant decreases as the proportion of monomer FNI increases. This is because fluorine atoms have strong electronegativity, which can attract the electron cloud to shift towards the center, thereby reducing the polarizability of the molecule.

[0094] (6) Figure 9 FPNI prepared for Examples 1-4 and Comparative Example 1 0.25 FPNI 0.5 FPNI 0.75 The conductivity diagrams of FPNI1 and PNI are derived from... Figure 9 It can be seen that at low frequencies, conductivity is mainly determined by the mobility of free carriers. However, as the frequency increases, processes such as dipole orientation polarization and interface polarization cannot keep up with the changes in the applied electric field, thus increasing conductivity. However, the FPNI (Functional Particle Noise) can still be observed. 0.5 It has the lowest electrical conductivity among all its components.

[0095] (7) Figure 11 FPNI prepared for Examples 1-4 and Comparative Example 1 0.25 FPNI 0.5 FPNI 0.75 The breakdown diagrams of FPNI1 and PNI are provided by... Figure 11 It can be seen that increasing the degree of fluorination improves the insulation properties of the polymer, with Example 2 exhibiting a higher insulation breakdown field strength of 574.57 MV / m. The introduction of fluorine atoms effectively increases the electronegativity of the polymer, thereby gaining stronger electron-withdrawing ability, constructing deeper electron traps, and enhancing the polymer's insulation performance.

[0096] Example 5

[0097] This embodiment uses the polymer FPNI prepared in Example 2. 0.5 Using 4,4-dihydroxydicyclohexane as the matrix, doping modification was performed, and the specific method is as follows:

[0098] Step 1: Weigh 0.1g of polymer FPNI 0.5 Add 0.0001 g of 4,4-dihydroxydicyclohexane (OH) to a solution containing 2 ml of dimethylformamide (DMF), stir at room temperature for 2 h to prepare a precursor solution, and then filter.

[0099] Step 2: The filtered precursor solution is coated onto a glass plate using a solution casting method to obtain a wet film. The wet film is dried at 60°C for 2 hours to obtain a dry film. The dry film is then vacuum dried at 60°C for 24 hours to obtain an FPNI film with a thickness of 5 μm. 0.5 -OH 0.1% film.

[0100] Example 6

[0101] The difference between this embodiment and Example 5 is that the amount of 4,4-dihydroxydicyclohexane in step one is 0.0003 g, while the remaining process steps and parameter settings are the same as in Example 1, resulting in FPNI with a thickness of 5 μm. 0.5 -OH 0.3% film.

[0102] Example 7

[0103] The difference between this embodiment and Example 5 is that the amount of 4,4-dihydroxydicyclohexane in step one is 0.001 g, while the remaining process steps and parameter settings are the same as in Example 1, resulting in FPNI with a thickness of 5 μm. 0.5 -OH 1% film.

[0104] Example 2

[0105] FPNI prepared in Examples 5-7 0.5 -OH 0.1% FPNI 0.5 -OH 0.3% FPNI 0.5 -OH 1% Characterized and compared with the FPNI prepared in Example 2 0.5 The comparison was conducted, and the specific tests and results are as follows:

[0106] (1) The HOMO and LUMO values ​​of the band spectra of FNI prepared in Comparative Example 1, FPNI prepared in Example 4, and 4,4-dihydroxydicyclohexane were simulated using the computer software Materials Studio 2023. The results are as follows: Figure 6 As shown, by Figure 6 It can be seen that FPNI has a wider band gap than PNI, while OH has a wider band gap than both FPNI and PNI. This indicates that, theoretically, fluorination of PNI and introduction of OH can improve the band gap of FNI.

[0107] (2) Figure 4 FPNI prepared for Examples 2 and 5-7 0.5 and FPNI 0.5 -OH 0.1% FPNI 0.5 -OH0.3% FPNI 0.5 -OH 1% The Fourier transform infrared (FTIR) image shows that -OH carries a large number of carbon-carbon single bonds and hydroxyl groups, therefore it is located in the 3650~3200 cm⁻¹ region on the FTIR spectrum. -1 The peak at 800 cm⁻¹ represents the stretching vibration of the hydroxyl group. Cyclohexane compounds, however, exhibit their own unique skeletal vibrational modes, specifically the stretching vibration of the carbon-carbon single bond at 800 cm⁻¹. -1 about.

[0108] (3) Figure 8 FPNI prepared for Examples 2 and 5-7 0.5 and FPNI 0.5 -OH 0.1% FPNI 0.5 -OH 0.3% FPNI 0.5 -OH 1% The dielectric spectrum shows that as the mass of -OH doping increases and the degree of cross-linking increases, the dielectric constant tends to decrease. Although the introduced -OH is an organic compound composed of two hydroxyl groups, which increases the dielectric constant, the three-dimensional network formed by its cross-linking structure restricts the movement of polymer chain segments, making the orientation polarization of dipoles more difficult and reducing the number of polar groups that can move or rotate freely, thus lowering the dielectric constant.

[0109] (4) Figure 10 FPNI prepared for Examples 2 and 5-7 0.5 and FPNI 0.5 -OH 0.1% FPNI 0.5 -OH 0.3% FPNI 0.5 -OH 1% The conductivity diagram shows that at low frequencies, conductivity is mainly determined by the mobility of free carriers. However, as the frequency increases, processes such as dipole orientation polarization and interface polarization cannot keep up with the changes in the applied electric field, thus increasing the conductivity. It can be seen that FPNI... 0.5 -OH 0.3% It has the lowest electrical conductivity among all its components.

[0110] (5) Figure 12 FPNI prepared for Examples 2 and 5-7 0.5 and FPNI 0.5 -OH 0.1% FPNI 0.5 -OH 0.3% FPNI 0.5 -OH 1%The breakdown diagram shows that Example 7 has a higher insulation breakdown field strength of 619.53 MV / m, which means that the addition of crosslinking agent -OH significantly improves the insulation performance of the polymer, so that the polymer does not break down under a high electric field and has excellent insulation properties.

[0111] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. An application of a polynorbornene imide insulating material, characterized in that, The method for preparing a wide-gap all-organic insulating film for winding insulation is as follows: polynorbornene imide insulating material and 4,4-dihydroxydicyclohexane are dissolved in an ultra-dry dichloromethane solution, and then a film is formed on a glass plate by solution casting. The wet film is dried to obtain a dry film, and the dry film is subjected to vacuum drying treatment to obtain a wide-gap all-organic insulating film for winding insulation. The preparation methods of polynorbornene imide insulating materials include: (i) The monomer N-phenylnorbornadieneimide is generated by amidation reaction of norbornadiene anhydride and aniline, named NI; the monomer N-pentafluorophenylnorbornadieneimide is generated by amidation reaction of norbornadiene anhydride and pentafluoroaniline, named FNI. (ii) Using NI and FNI as raw materials, a ring-opening metathesis polymerization reaction was carried out to obtain polynorbornene imide insulating material; The molar percentage of NI in monomeric NI and FNI is 25%, 50%, or 75%, respectively.

2. The application according to claim 1, characterized in that, (a) The operation process is as follows: (1) Dissolve norborneol in glacial acetic acid solution to obtain solution A; (2) Add aniline or pentafluoroaniline to solution A and stir until homogeneous to obtain solution B; (3) Add the catalyst to solution B, heat and stir at 120°C to react completely to obtain solution C; (4) After solution C is cooled to room temperature, deionized water is added, and the solution is filtered under vacuum to obtain a white solid. After washing, the solid is purified by column chromatography and dried to obtain NI or FNI.

3. The application according to claim 2, characterized in that, The molar ratio of norborneol olefinic anhydride to aniline or pentafluoroaniline is 1:1.2, and the catalyst is 4-dimethylaminopyridine.

4. The application according to claim 1, characterized in that, (ii) The operation process is as follows: Step 1: Under a dry nitrogen atmosphere, dissolve NI and FNI in an ultra-dry dichloromethane solution to obtain solution D; Step 2: Under a dry nitrogen atmosphere, dissolve the Grubbs II catalyst in an ultra-dry dichloromethane solution to obtain solution E; Step 3: Under a dry nitrogen atmosphere, mix solutions D and E, stir at room temperature until the reaction is complete, add the stopping agent vinyl ether, and continue stirring for 30-40 minutes. Step four: The reacted solution is added dropwise to methanol to obtain a solid product. Using methanol as a solvent, the solid product is subjected to Soxhlet extraction for 48 hours. Finally, it is vacuum dried at 60-65℃ for 48 hours to obtain polynorbornene imide insulating material.

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