Polynorbornene imide insulating material as well as preparation method and application thereof

Abstract

The invention discloses a polynorbornene imide insulating material as well as a preparation method and application thereof, and belongs to the technical field of electrical insulating materials and preparation thereof. The problem that an existing polynorbornene imide dielectric film is poor in insulation performance is solved. FPNI is obtained through fluorination modification of a polymer dielectric film polynorbornene imide (PNI) of an organic rigid main chain with a wide band gap and a high glass transition temperature, and the FPNI is doped with an organic molecule 4, 4-dihydroxydicyclohexane (OH) with a wide band gap, so that hydrogen bond crosslinking between hydroxyl and fluorine atoms is realized, and the performance of the polymer dielectric film is improved. And moreover, OH with a wide band gap can bring a higher electron transition energy level, the cross-linked polymer film with excellent insulating property is obtained, and the breakdown field strength is 619.53 MV / m.

Description

Technical Field

[0001] The present invention relates to a poly(norborneneimide) insulating material, a preparation method thereof and an application thereof, belonging to the technical field of electrical insulating materials and their preparation. Background Art

[0002] During the long-term operation of an electric machine, due to reasons such as aging, humidity, mechanical damage, overvoltage or temperature rise, the insulating material between windings loses its original insulating performance, which may lead to unstable operation of electrical equipment and even failures. Therefore, with the development of electrical equipment towards high voltage, high power and high efficiency, the requirements for winding insulating materials are also getting higher and higher. Traditional winding insulating materials such as fiber paper, epoxy resins, etc. are widely used because of their low price and high mechanical strength. However, modern power and electric machine equipment puts forward higher requirements for the performance of winding insulating materials. Therefore, developing a winding insulating material with excellent electrical insulation stability has become the current research focus.

[0003] Poly(norborneneimide)-based materials have gradually become a research hotspot for new winding insulating materials due to their excellent properties such as high temperature resistance and high field resistance. However, due to the softening and aging phenomena at high temperatures, the electrical properties of poly(norborneneimide)-based materials will gradually decline during long-term use. Therefore, it is very necessary to further improve the insulating performance of poly(norborneneimide) dielectric films to provide a more excellent material choice for the winding insulation of power equipment. Summary of the Invention

[0004] Aiming at the problem of poor insulating performance of existing poly(norborneneimide) dielectric films, the present invention provides a poly(norborneneimide) insulating material, a preparation method thereof and an application thereof.

[0005] The technical solution of the present invention:

[0006] One of the purposes of the present invention is to provide a preparation method of a poly(norborneneimide) insulating material, and the method includes the following steps:

[0007] (1) Amidating norbornene dianhydride and aniline to generate a monomer N-(phenyl)norbornene diamide, named NI; amidating norbornene dianhydride and pentafluoroaniline to generate a monomer N-(pentafluorophenyl)norbornene diamide, named FNI;

[0008] (2) Using NI and / or FNI as raw materials for ring-opening metathesis polymerization reaction to obtain a poly(norborneneimide) insulating material.

[0009] Further defined, the operation process of (1) is:

[0010] (1) Dissolving norbornene dianhydride in an acetic acid solution to obtain solution A;

[0011] (2) Add aniline or pentafluoroaniline to Solution A and stir evenly to obtain Solution B;

[0012] (3) Add a catalyst to Solution B, heat and stir at 120 °C for 24 h to obtain Solution C;

[0013] (4) After Solution C is cooled to room temperature, add deionized water, perform vacuum filtration to obtain a white solid, wash it, and then use column chromatography for purification and drying to obtain NI or FNI.

[0014] Further limit that the molar ratio of norbornene dianhydride to aniline or pentafluoroaniline is 1:1.2.

[0015] Further limit that the catalyst is 4-dimethylaminopyridine.

[0016] Further limit that the mass ratio of norbornene dianhydride to aniline or pentafluoroaniline is 2.46:0.585.

[0017] Further limit that the mass-volume ratio of norbornene dianhydride to glacial acetic acid in Solution A of (1) is 2.46 g:25 mL.

[0018] Further limit that the mobile phase in column chromatography is prepared from ethyl acetate and n-hexane in a ratio of 1:5.

[0019] Further limit that the operation process of (2) is as follows:

[0020] Step 1, dissolve NI and FNI in an ultra-dry dichloromethane solution under a dry nitrogen environment to obtain Solution D;

[0021] Step 2, dissolve the Grubbs II generation catalyst in an ultra-dry dichloromethane solution under a dry nitrogen environment to obtain Solution E;

[0022] Step 3, mix Solution D and Solution E under a dry nitrogen environment, stir and react completely at room temperature, add the terminator vinyl ethyl ether, and then continue to stir for 30 - 40 min;

[0023] Step 4, drop the reacted solution into a methanol solution to obtain a solid product, perform Soxhlet extraction of the solid product with methanol for 48 h, and finally vacuum dry at 60 - 65 °C for 48 h to obtain a poly(norbornene imide) insulating material.

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

[0025] The second object of the present invention is to provide a poly(norbornene imide) insulating material prepared by the above method.

[0026] The third object of the present invention is to provide an application of the above-mentioned polynorbornene imide insulating material, specifically for preparing polynorbornene imide insulating film.

[0027] It is further defined that the preparation method is: dissolving the poly(norbornene imide) insulating material in an ultra-dry dichloromethane solution, then forming a film on a glass plate by a solution casting method to obtain a wet film, drying the obtained dry film, and vacuum drying the dry film to obtain a poly(norbornene imide) insulating film.

[0028] It is further defined that the mass fraction of the polymer in the casting solution is 5%.

[0029] It is further defined that the drying treatment temperature is 60-65°C and the time is 2-4h.

[0030] It is further defined that the vacuum drying treatment conditions are: drying treatment at 60-65°C vacuum conditions for 24 hours.

[0031] It is further defined that the thickness of the obtained polynorbornene imide film is 5-8 μm.

[0032] A fourth object of the present invention is to provide an application of the above-mentioned polynorbornene imide insulating material, specifically for preparing a wide bandgap all-organic insulating film for winding insulation.

[0033] It is further defined that the preparation method is: dissolving polybornene imide insulating material and 4,4-dihydroxydicyclohexane in an ultra-dry dichloromethane solution, and then forming a film on a glass plate by a solution casting method to obtain a wet film, drying the obtained dry film, and vacuum drying the dry film to obtain a winding insulation wide bandgap all-organic insulating film.

[0034] It is further defined that the mass ratio of the polynorbornene imide insulating material to 4,4-dihydroxydicyclohexane is 0.1:(0.0001-0.001).

[0035] It is further defined that the mass fraction of the casting solution is 5%.

[0036] It is further defined that the drying treatment temperature is 60-65°C and the time is 2-4h.

[0037] It is further defined that the vacuum drying treatment conditions are: drying treatment at 60-65°C vacuum conditions for 24 hours.

[0038] It is further defined that the thickness of the obtained polynorbornene imide film is 5-8 μm.

[0039] A fifth object of the present invention is to provide an application of the insulating film prepared by the above method, specifically as an insulating medium for the preparation of electrical insulating devices.

[0040] Further defined, the electrical insulating devices include smart grids, new energy vehicles, and AC / DC transmission networks.

[0041] Beneficial effects:

[0042] In the present invention, the polymer dielectric film poly(norbornene imide) (PNI) with an organic rigid main chain having a wide bandgap and a high glass transition temperature is fluorinated to obtain FPNI, and by doping the organic molecule 4,4-dihydroxy dicyclohexane (OH) with a wide bandgap in FPNI, not only the hydrogen bond crosslinking between hydroxyl groups and fluorine atoms is achieved, but also the wide bandgap OH can bring higher electron transition energy levels, obtaining a crosslinked polymer film with excellent insulating properties, and the breakdown field strength is 619.53 MV / m. Compared with the prior art, the present invention has at least the following advantages:

[0043] (1) In the present invention, by fluorinating norbornene imide, the electronegativity of the polymer is enhanced by the introduction of fluorine atoms, increasing the electron-withdrawing ability and trap depth of the polymer, thereby improving the breakdown field strength of the polymer.

[0044] (2) The present invention further improves the insulating properties of the material by doping alicyclic hydroxyl groups (OH) with a relatively wide bandgap. Specifically, the hydrogen atoms in the hydroxyl groups form hydrogen bonds with the fluorine atoms in the polymer FPNI. The formation of hydrogen bonds not only enhances the interaction between materials, but also constructs a network crosslinked structure, effectively reducing the dielectric loss and improving the breakdown strength of the dielectric material, enabling the material to withstand a greater voltage under high electric field conditions without insulation failure.

[0045] (3) The synthesis process of the insulating material provided by the present invention is simple, with mature large-scale preparation technology, and existing industrial equipment can meet the production requirements. Moreover, it can maintain the flexibility and uniformity of the polymer material, effectively solving various challenges faced in industrialization such as agglomeration and deterioration of mechanical properties caused by doping modification, and mismatch of polymer matrix forming technology, providing a guiding idea for large-scale preparation of all-organic dielectric films for winding insulation. Description of the drawings

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

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

[0048] Figure 3 FPNI prepared in Examples 1-4 and Comparative Example 10.25 , FPNI 0.5 , FPNI 0.75 , FPNI 1 and Fourier transform infrared spectra of PNI;

[0049] Figure 4 FPNI prepared in Example 2 and Examples 5 - 7 0.5 and FPNI 0.5 -OH 0.1％ , FPNI 0.5 -OH 0.3％ , FPNI 0.5 -OH 1％ and Fourier transform infrared spectra;

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

[0051] Figure 6 PNI prepared in Comparative Example 1, FPNI prepared in Example 4 1 and energy band diagrams of 4,4 - dihydroxy dicyclohexane;

[0052] Figure 7 FPNI prepared in Examples 1 - 4 and Comparative Example 1 0.25 , FPNI 0.5 , FPNI 0.75 , FPNI 1 and dielectric spectra of PNI;

[0053] Figure 8 FPNI prepared in Example 2 and Examples 5 - 7 0.5 and FPNI 0.5 -OH 0.1％ , FPNI 0.5 -OH 0.3％ , FPNI 0.5 -OH 1％ dielectric spectra;

[0054] Figure 9 FPNI prepared in Examples 1 - 4 and Comparative Example 1 0.25 , FPNI 0.5 , FPNI 0.75 , FPNI 1 and conductivity diagrams of PNI;

[0055] Figure 10 FPNI prepared in Example 2 and Examples 5 - 70.5 and FPNI 0.5 -OH 0.1％ 、FPNI 0.5 -OH 0.3％ 、FPNI 0.5 -OH 1％ conductivity diagrams;

[0056] Figure 11 FPNI prepared in Examples 1 to 4 and Comparative Example 1 0.25 、FPNI 0.5 、FPNI 0.75 、FPNI 1 and PNI comparison diagrams of breakdown characteristics at room temperature;

[0057] Figure 12 FPNI prepared in Example 2 and Examples 5 to 7 0.5 and FPNI 0.5 -OH 0.1％ 、FPNI 0.5 -OH 0.3％ 、FPNI 0.5 -OH 1％ comparison diagrams of breakdown characteristics at room temperature. Detailed implementation manners

[0058] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following describes the detailed implementation manners of the present invention in conjunction with the embodiments of the specification.

[0059] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0060] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation manner 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 separate or alternative embodiment that excludes other embodiments.

[0061] The experimental methods used in the following embodiments are all conventional methods unless otherwise specified. The materials, reagents, methods, and instruments used, unless otherwise specified, are all conventional materials, reagents, methods, and instruments in the art. Those skilled in the art can obtain them through commercial channels, and the purities of the solid and liquid reagents used are all analytical pure.

[0062] Example 1

[0063] Step 1: Prepare two portions of Solution A for standby. The specific preparation method for each portion is as follows: Weigh 2.46 g of norbornene dianhydride and dissolve it in 25 ml of glacial acetic acid at room temperature to obtain Solution A;

[0064] Step 2: Weigh 0.585 g of 4-dimethylaminopyridine (DMAP) and put it into 1.51 g of aniline solution for dissolution to obtain Solution B;

[0065] Step 3: Mix one portion of Solution A and Solution B, then put the mixture into a conical flask blown with dry nitrogen, heat it under reflux with magnetic stirring, the heating temperature is 120 °C, and monitor the reaction by thin-layer chromatography (the developing agent is prepared from ethyl acetate and n-hexane according to a volume ratio of 1:5) until the reaction is complete;

[0066] Step 4: Cool the completely reacted mixed solution after reflux to room temperature, pour it into a large amount of deionized water to produce a white precipitate and filter it. After washing and filtering the precipitate multiple times, make the washing solution neutral;

[0067] Step 5: Then purify it by column chromatography and dry it to obtain monomer NI (the mobile phase is prepared from ethyl acetate and n-hexane according to a volume ratio of 1:5);

[0068] Step 6: Weigh 0.585 g of 4-dimethylaminopyridine (DMAP) and put it into 2.96 g of pentafluoroaniline solution for dissolution to obtain Solution C;

[0069] Step 7: Mix the other portion of Solution A and Solution C, then put the mixture into a conical flask blown with dry nitrogen, heat it under reflux with magnetic stirring at a temperature of 120 °C, and monitor the reaction by thin-layer chromatography (the developing agent is prepared from ethyl acetate and n-hexane according to a volume ratio of 1:5) until the reaction is complete;

[0070] Step 8: Cool the completely reacted mixed solution after reflux to room temperature, pour it into a large amount of deionized water to produce a white precipitate and filter it. After washing and filtering the precipitate multiple times, make the washing solution neutral;

[0071] Step 9: Then purify it by column chromatography and dry it to obtain monomer FNI (the mobile phase is prepared from ethyl acetate and n-hexane according to a volume ratio of 1:5);

[0072] Step 10: Weigh 0.502 g of monomer NI and 2.073 g of monomer FNI and put them into a Schlenk tube with a four-way teflon stopcock that has been subjected to anhydrous and anaerobic treatment, and inject 20 ml of ultra-dry dichloromethane into the Schlenk tube under nitrogen protection;

[0073] Step 11: Put 17.8 mg of Grubbs II catalyst into another Schlenk tube containing 2 ml of ultra-dry dichloromethane and dissolve it to obtain Solution D;

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

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

[0076] Step Fourteen: Drop the solution evenly into the methanol solution to produce a precipitate. Wash the precipitate with a Soxhlet extractor, and place the precipitate in a vacuum oven and dry it at 60 °C for 48 h to obtain the polymer FPNI 0.25 ;

[0077] Step Fifteen: Dissolve the dried polymer FPNI 0.25 in dichloromethane to prepare a 5 wt% precursor solution and filter it, then stir at room temperature for 2 h;

[0078] Step Sixteen: Coat it on a glass plate by the solution casting method to obtain a wet film. Dry the wet film at 60 °C for 2 h to obtain a dry film, and then dry the dry film in a vacuum at 60 °C for 24 h to obtain an FPNI 0.25 film with a thickness of 5 μm.

[0079] Example 2

[0080] The difference between this example and Example 1 is that in Step Ten, the monomer NI is 1 g and the monomer FNI is 1.38 g. The rest of the process steps and parameter settings are the same as those in Example 1, obtaining the polymer FPNI 0.5 , and an FPNI 0.5 film with a thickness of 5 μm.

[0081] Example 3

[0082] The difference between this example and Example 1 is that in Step Ten, the monomer NI is 1.51 g and the monomer FNI is 0.7 g. The rest of the process steps and parameter settings are the same as those in Example 1, obtaining the polymer FPNI 0.75 , and an FPNI 0.75 film with a thickness of 5 μm.

[0083] Example 4

[0084] The difference between this example and Example 1 is that in Step Ten, the monomer NI is 0 g and the monomer FNI is 2.764 g. The rest of the process steps and parameter settings are the same as those in Example 1, obtaining the polymer FPNI 1 , and an FPNI 1 film with a thickness of 5 μm.

[0085] Comparative Example 1

[0086] The difference between this comparative example and Example 1 is as follows: in Step 10, the monomer NI is 2 g and the monomer FNI is 0 g, and the remaining process steps and parameter settings are the same as those in Example 1, obtaining the polymer FPNI 1 , and a PNI film with a thickness of 5 μm.

[0087] Effect Example 1

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

[0089] (1) The nuclear magnetic resonance hydrogen spectrum of the monomer NI prepared in Comparative Example 1 is as Figure 1 shown. It can be seen from Figure 1 that the peaks of the two hydrogens of the amino group on aniline have disappeared in the nuclear magnetic resonance hydrogen spectrum, and instead, the hydrogen spectrum distribution of norbornene dianhydride appears. Moreover, the integrated area of the characteristic peaks of the hydrogen spectrum of the monomer corresponds one by one to the number of hydrogens of the synthesis target, proving that the NI monomer has been successfully synthesized.

[0090] (2) The nuclear magnetic resonance hydrogen spectrum of the monomer FNI prepared in Example 4 is as Figure 2 shown. It can be seen from Figure 2 that the peaks of the two hydrogens of the amino group on pentafluoroaniline have disappeared in the nuclear magnetic resonance hydrogen spectrum, and instead, the hydrogen spectrum distribution of norbornene dianhydride appears. Moreover, the integrated area of the characteristic peaks of the hydrogen spectrum of the monomer corresponds one by one to the number of hydrogens of the synthesis target, proving that the FNI monomer has been successfully synthesized.

[0091] (3) Figure 3 are the Fourier infrared diagrams of the FPNI 0.25 , FPNI 0.5 , FPNI 0.75 , FPNI 1 and PNI prepared in Examples 1 to 4 and Comparative Example 1. It can be seen from Figure 3 that the wavelength range of the C-F bond in the infrared spectrum is approximately 1050 - 1350 cm -1 . By comparison, it can be seen that at 1136.6 cm -1 in the infrared spectrum, as the fluorination ratio increases, the intensity of the peak increases. Therefore, it is proved that the successful synthesis of the polymer and the successful introduction of the monomer FNI.

[0092] (4) Figure 5 are the FPNI 0.5 and FPNI 0.5 -OH 0.1％ , FPNI 0.5 -OH 0.3％ , FPNI0.5 -OH 1％ XRD comparison chart of Figure 5 It can be seen that the polymer modification schemes are respectively fluorination and introduction of organic compounds, and no characteristic peaks are shown in the XRD, so it meets the expected goal.

[0093] (5) Figure 7 FPNI prepared for Examples 1 to 4 and Comparative Example 1 0.25 、FPNI 0.5 、FPNI 0.75 、FPNI 1 and the dielectric spectroscopy diagrams of PNI, by Figure 7 It can be seen that the dielectric losses are all maintained at a relatively low value, but as the proportion of monomer FNI increases, the dielectric constant decreases. This is because fluorine atoms have a strong electronegativity, which can attract the electron cloud to shift towards the center, thus reducing the molecular polarizability.

[0094] (6) Figure 9 FPNI prepared for Examples 1 to 4 and Comparative Example 1 0.25 、FPNI 0.5 、FPNI 0.75 、FPNI 1 and the conductivity diagrams of PNI, by Figure 9 It can be seen that at low frequencies, the conductance is mainly determined by the mobility of free carriers. As the frequency increases, processes such as dipole orientation polarization and interfacial polarization cannot keep up with the change of the applied electric field, thus increasing the conductivity. However, it can still be seen that FPNI 0.5 has a lower conductivity among all components.

[0095] (7) Figure 11 FPNI prepared for Examples 1 to 4 and Comparative Example 1 0.25 、FPNI 0.5 、FPNI 0.75 、FPNI 1 and the breakdown diagrams of PNI, by Figure 11 It can be seen that the increase in the degree of fluorination will improve the insulating property of the polymer. Example 2 has a higher insulation breakdown field strength of 574.57 MV / m. The introduction of fluorine atoms effectively increases the electronegativity of the polymer, thereby obtaining a stronger electron-withdrawing ability, constructing deeper electron traps, and enhancing the insulating performance of the polymer.

[0096] Example 5

[0097] In this example, the polymer FPNI 0.5 prepared in Example 2 was used as the matrix, and 4,4-dihydroxy dicyclohexane was used for doping modification. The specific method is as follows:

[0098] Step 1: Weigh 0.1 g of polymer FPNI 0.5 and 0.0001 g of 4,4-dihydroxy dicyclohexane (OH) and put them into a 2 ml dimethylformamide (DMF) solution. Stir at room temperature for 2 h to prepare a precursor solution and filter it;

[0099] Step 2: Coat the filtered precursor solution on a glass plate by the solution casting method to obtain a wet film. Dry the wet film at 60 °C for 2 h to obtain a dry film, and then dry the dry film in a vacuum at 60 °C for 24 h to obtain an FPNI 0.5 -OH 0.1％ thin film with a thickness of 5 μm.

[0100] Example 6

[0101] The difference between this example and Example 5 is that in Step 1, the amount of 4,4-dihydroxy dicyclohexane is 0.0003 g, and the other process steps and parameter settings are the same as those in Example 1, obtaining an FPNI 0.5 -OH 0.3％ thin film with a thickness of 5 μm.

[0102] Example 7

[0103] The difference between this example and Example 5 is that in Step 1, the amount of 4,4-dihydroxy dicyclohexane is 0.001 g, and the other process steps and parameter settings are the same as those in Example 1, obtaining an FPNI 0.5 -OH 1％ thin film with a thickness of 5 μm.

[0104] Effect Example 2

[0105] Characterize the FPNI 0.5 -OH 0.1％ prepared in Examples 5 to 7, FPNI 0.5 -OH 0.3％ and FPNI 0.5 -OH 1％ and compare them with the FPNI prepared in Example 2 0.5 The specific detections and results are as follows:

[0106] (1) Through the simulation of the computer software Materials Studio 2023, the HOMO and LUMO values of the energy band spectra of FNI prepared in Comparative Example 1, FPNI prepared in Example 4, and 4,4-dihydroxy dicyclohexane are simulated, and the results are as Figure 6 shown. It can be seen from Figure 6 that FPNI has a wider band gap than PNI, and OH has a wider band gap than FPNI and PNI. This indicates that theoretically, fluorination of PNI and introduction of OH can increase the band gap of FNI.

[0107] (2) Figure 4 FPNI prepared for Example 2 and Examples 5 - 7 0.5 and FPNI 0.5 -OH 0.1％ 、FPNI 0.5 -OH 0.3％ 、FPNI 0.5 -OH 1％ The Fourier transform infrared spectra of, it can be seen from the figure that -OH has a large number of carbon - carbon single bonds and hydroxyl groups, so the stretching vibration peak of the hydroxyl group is located at 3650 - 3200 cm -1 . And cyclohexane compounds will have their own unique skeletal vibration mode, that is, the stretching vibration of carbon - carbon single bonds is around 800 cm -1 .

[0108] (3) Figure 8 FPNI prepared for Example 2 and Examples 5 - 7 0.5 and FPNI 0.5 -OH 0.1％ 、FPNI 0.5 -OH 0.3％ 、FPNI 0.5 -OH 1％ The dielectric spectra of. It can be seen from the figure that as the mass of -OH doping increases and the degree of cross - linking increases, the dielectric constant shows a downward trend. Although the introduced -OH is an organic compound and consists of two hydroxyl groups, which would increase the value of the dielectric constant, the three - dimensional network formed by the establishment of its cross - linked structure will limit the movement of polymer segments, making the orientation polarization of dipoles more difficult and reducing the number of polar groups that can move or rotate freely, thus reducing the dielectric constant.

[0109] (4) Figure 10 FPNI prepared for Example 2 and Examples 5 - 7 0.5 and FPNI 0.5 -OH 0.1％ 、FPNI 0.5 -OH 0.3％ 、FPNI 0.5 -OH 1％ The conductivity diagrams of. It can be known from the figure that at low frequencies, the conductivity is mainly determined by the mobility of free carriers, and as the frequency increases, processes such as dipole orientation polarization and interfacial polarization cannot keep up with the change of the applied electric field, thus increasing the conductivity. It can be seen that FPNI 0.5 -OH 0.3％ has a relatively low conductivity among all components.

[0110] (5) Figure 12The FPNI prepared for Example 2 and Examples 5 to 7 0.5 and FPNI 0.5 -OH 0.1％ 、FPNI 0.5 -OH 0.3％ 、FPNI 0.5 -OH 1％ The breakdown diagrams of. It can be seen from the figure that Example 7 has a higher insulation breakdown field strength of 619.53 MV / m, that is, the addition of the crosslinking agent -OH significantly increases the insulation performance of the polymer, so that the polymer does not break down under a higher electric field and has excellent insulation characteristics.

[0111] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various modifications and decorations without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims

1. A method for preparing a polynorbornene imide insulating material, characterized in that: include: (i) Amidation reaction is carried out with nadic anhydride and aniline to generate a monomer N-(phenyl)nadic acid amide, named NI; Amidation reaction is carried out with nadic anhydride and pentafluoroaniline to generate a monomer N-(pentafluorophenyl)nadic acid amide, named FNI; (ii) using NI and / or FNI as raw materials to carry out a ring-opening metathesis polymerization reaction to obtain polynorbornene imide insulating materials.

2. The preparation method according to claim 1, characterized in that: The operation process of (I) is as follows: (1) dissolving nadic anhydride in glacial acetic acid solution to obtain solution A; (2) adding aniline or pentafluoroaniline to solution A and stirring evenly to obtain solution B; (3) Add the catalyst to solution B, heat and stir at 120°C to react, and complete the reaction to obtain solution C; (4) After solution C is cooled to room temperature, deionized water is added and vacuum filtered to obtain a white solid, which is then washed, purified by column chromatography and dried to obtain NI or FNI.

3. The preparation method according to claim 2, characterized in that: The amount ratio of nadic anhydride to aniline or pentafluoroaniline is 1:1.2; the catalyst is 4-dimethylaminopyridine, and the mass ratio of nadic anhydride to aniline or pentafluoroaniline is 2.46:0.

585.

4. The preparation method according to claim 1, characterized in that: The operation process of (II) is as follows: Step 1, under a dry nitrogen environment, dissolving NI and FNI in an ultra-dry dichloromethane solution to obtain a solution D; Step 2, under a dry nitrogen environment, dissolving the Grubbs II generation catalyst in an ultra-dry dichloromethane solution to obtain a solution E; Step 3, under a dry nitrogen environment, solution D and solution E were mixed, stirred at room temperature until the reaction was complete, and then vinyl ethyl ether was added as a stop agent and stirring was continued for 30-40 minutes; Step 4, adding the reaction solution dropwise into a methanol solution to obtain a solid product, performing Soxhlet extraction on the solid product using methanol as a solution for 48 hours, and finally vacuum drying at 60-65° C. for 48 hours to obtain a polynorbornene imide insulating material.

5. The preparation method according to claim 4, characterized in that: The amount of NI in the mixed monomers NI and FNI is 0%, 25%, 50%, 75% or 100%.

6. A polynorbornene imide insulating material prepared by the method according to any one of claims 1 to 5.

7. An application of the polynorbornene imide insulating material according to claim 6, characterized in that: The invention is used for preparing poly (norbornene imide) insulating film, and the preparation method is as follows: dissolving the poly (norbornene imide) insulating material in an ultra-dry dichloromethane solution, and then forming a film on a glass plate by a solution casting method to obtain a wet film, drying the obtained wet film, and vacuum drying the dry film to obtain the poly (norbornene imide) insulating film.

8. An application of the polynorbornene imide insulating material according to claim 6, characterized in that: The invention is used for preparing a wide band gap all-organic insulating film for winding insulation. The preparation method is as follows: a polynorbornene imide insulating material and a 4,4-dihydroxydicyclohexane solution are placed in an ultra-dry dichloromethane solution, and then a film is formed on a glass plate by a solution casting method to obtain a wet film, drying the obtained dry film, and vacuum drying the dry film to obtain a wide band gap all-organic insulating film for winding insulation.

9. Use of an insulating film prepared by the method according to claim 7 or 8, characterized in that: Used as insulating medium in the preparation of electrical insulation devices.

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