Polyetherimide dielectric film containing indane ring structure and preparation method and application thereof

Abstract

The invention relates to the technical field of dielectric materials, in particular to a polyetherimide dielectric film containing an indane ring structure and a preparation method and application of the polyetherimide dielectric film. The polyetherimide dielectric film containing the indane ring structure is obtained by carrying out polymerization reaction and imidization reaction on diamine monomers containing chain segments shown in the formula I and dianhydride monomers. The polyetherimide dielectric film provided by the invention has relatively high room-temperature and high-temperature breakdown field strength, and also has good high-temperature energy storage performance, and the preparation method is simple and suitable for industrial application. Formula I

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dielectric materials, and particularly relates to a polyetherimide dielectric film containing an indane ring structure and a preparation method and application thereof. BACKGROUND

[0002] Polymer dielectric energy storage capacitors are key components in modern electronic and power systems, but the current commercial capacitors have low energy storage density and their performance sharply decreases in extreme environments such as high temperature, which seriously limits their application in aerospace, new energy vehicles and other fields. Although the widely used biaxially oriented polypropylene (BOPP) film has low dielectric loss, its dielectric constant is only about 2.2, resulting in limited energy storage density; although polyvinylidene fluoride (PVDF) has a relatively high dielectric constant (about 8-10), it has high dielectric loss and early polarization saturation problems, and the discharge efficiency is usually less than 30%, and the energy density is also difficult to exceed 2 J / cm 3 Polyetherimide (PEI) is formed by the condensation reaction of specific diamine monomers and anhydride monomers containing ether bonds to form polyether amide acid, and then dehydrated and cyclized at high temperature. Because of its high insulation, excellent thermal stability and controllable molecular structure, it has become a potential high-temperature dielectric material.

[0003] However, the breakdown field strength of the existing polyetherimide is still low, which cannot meet the application requirements in extreme conditions. The current methods for improving the breakdown field strength of polyetherimide mainly include adding fillers and designing multi-layer structures. For example, by adding nickel-based metal organic framework nanosheets (Ni-MOFs), the Ni-MOFs / PEI dielectric nanocomposite containing 2 wt% Ni-MOFs exhibits a breakdown field strength of 640 kV / mm and a discharge energy density of 6.37 J / cm 3 at 150℃. However, the introduction of fillers easily leads to interface defects and electric field concentration, causing early breakdown; at the same time, the inorganic fillers have poor compatibility with the polymer matrix, which reduces the flexibility and processing performance of the material, and the obtained dielectric material has unstable performance. For another example, by designing a sandwich structure, such as using a linear polyetherimide (PEI) dielectric as an outer layer and a poly (vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) composite as an intermediate layer, the three-layer composite realizes an ultra-high energy storage density of 18.9 J / cm 3 at 625 MV / m; although the multi-layer structure can synergistically regulate the electric field distribution, its process is complex and the cost is high, which is difficult to scale up. Therefore, it is urgent to provide a high-breakdown-field-strength dielectric material with stable performance and simple preparation process to meet the industrialization needs. SUMMARY

[0004] The application provides a polyetherimide dielectric film containing an indane ring structure and a preparation method and application thereof.

[0005] The application provides a polyetherimide dielectric film containing an indane ring structure, which is obtained by polymerization and imidization reaction of a diamine monomer containing a chain segment shown in formula I and a dianhydride monomer, Formula I.

[0006] Optionally, the diamine monomer containing the chain segment shown in formula I includes at least one of 1-(4-aminophenyl)-1,3,3-trimethyl-2,3-dihydro-1H-inden-5-amine and 3-(4-aminophenyl)-1,1,3-trimethyl-2,3-dihydro-1H-inden-5-amine.

[0007] Optionally, the dianhydride monomer includes at least one of 4,4'-(4,4'-isopropyl diphenyloxy) diphthalic anhydride and 4,4'-(hexafluoroisopropyl) diphthalic anhydride.

[0008] Optionally, when the dianhydride monomer includes 4,4'-(4,4'-isopropyl diphenyloxy) diphthalic anhydride and 4,4'-(hexafluoroisopropyl) diphthalic anhydride, the molar ratio of the 4,4'-(4,4'-isopropyl diphenyloxy) diphthalic anhydride and 4,4'-(hexafluoroisopropyl) diphthalic anhydride is 1:0-4.

[0009] Optionally, the polyetherimide dielectric film containing the indane ring structure has a thickness of 9-25 μm.

[0010] The application further provides a preparation method of the polyetherimide dielectric film containing the indane ring structure. The diamine monomer containing the chain segment shown in formula I, the dianhydride monomer and a solvent are mixed to perform polymerization reaction, so as to obtain a polyamide acid solution, Formula I After the polyamide acid solution is sequentially subjected to bubble removal and film formation, imidization reaction is performed, so as to obtain the polyetherimide dielectric film containing the indane ring structure.

[0011] Optionally, the solvent includes at least one of N-methyl pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and m-cresol.

[0012] Optionally, the total mass of the diamine monomer and the dianhydride monomer containing the segment shown in formula I accounts for 10-20 wt% of the mass of the mixed solution of the diamine monomer, the dianhydride monomer and the solvent containing the segment shown in formula I.

[0013] Optionally, the polymerization reaction is carried out at room temperature, and the polymerization reaction time is 24-30 h.

[0014] Optionally, the imidization reaction is carried out under a gradient temperature program, and the gradient temperature program is sequentially incubating at 80-90℃ for 0.5-0.8 h, at 105-115℃ for 0.5-0.8 h, at 150-170℃ for 0.8-1.2 h, at 190-210℃ for 0.8-1.2 h, at 215-225℃ for 0.8-1.2 h, at 250-270℃ for 0.8-1.2 h, and at 290-300℃ for 0.8-1.2 h.

[0015] The application further provides an application of the polyetherimide dielectric film containing an indane ring structure in a dielectric capacitor.

[0016] Compared with the prior art, the application has the following beneficial effects: The polyetherimide dielectric film containing indane ring structure provided by the application is obtained by polymerization and imidization reaction of diamine monomers and dianhydride monomers containing the chain segment shown in formula I, wherein the structure shown in formula I contains indane ring structure and three methyl groups, which constitutes a large and rigid side group, and this structure constitutes a large steric hindrance in the polymer chain, effectively inhibiting the free rotation and close stacking of the molecular chain, greatly increasing the tortuosity of the charge migration path in the material, inhibiting the formation and spread of electrical trees, and thus significantly improving the breakdown field strength. In addition, the electron-rich indane aromatic ring itself can act as a powerful charge capture site, and compared with linear 1,4-benzene diamine, this structure introduces deeper trap energy levels in the polymer energy band. Under the action of a high external electric field, these deep trap energies can effectively capture and bind the injected carriers (electrons or holes), preventing their further migration and accumulation to form a destructive conductive channel, thereby delaying the occurrence of electrical breakdown. According to the description of the examples, the polyetherimide dielectric film containing indane ring structure provided by the application has a breakdown field strength of 645.98-678.35 kV / mm at 150℃ and 606.52-651.82 kV / mm at 200℃, which is significantly higher than that of the polyetherimide dielectric film without indane ring structure, and it also has a glass transition temperature of 250℃ or higher (251.15-291.59℃), and a higher high-temperature energy storage performance (the discharge energy density at 200℃, 90% energy storage efficiency can reach 2.93-4.38 J / cm 3 , which can stably operate at 200℃ environment). BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and other objects, features and advantages of the present application will become apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings, which show, by way of illustration, the principles of the application: Figure 1 The structure of the polyetherimide in the films obtained in Examples 1, 3 and Comparative Example 1 is shown.

[0018] Figure 2 The Fourier transform infrared spectrograms of the films obtained in Examples 1-4 and Comparative Example 1 are shown.

[0019] Figure 3 The X-ray diffraction patterns of the films obtained in Examples 1-4 and Comparative Example 1 are shown.

[0020] Figure 4 The differential scanning calorimetry curves of the films obtained in Examples 1-4 and Comparative Example 1 are shown.

[0021] Figure 5 The room temperature fluorescence emission spectrograms of the films obtained in Examples 1, 3 and Comparative Example 1 are shown.

[0022] Figure 6 The dielectric spectroscopy test results of the thin films obtained in Examples 1-4 and Comparative Example 1 are shown.

[0023] Figure 7 The Weibull distribution plots of the thin films obtained in Examples 1-4 and Comparative Example 1 at 150°C and 200°C are shown.

[0024] Figure 8 The energy storage test results of the thin films obtained in Examples 1-4 and Comparative Example 1 at 200°C and 250°C are shown. DETAILED DESCRIPTION

[0025] The present application will be described in detail below with specific embodiments, and it will be understood by those skilled in the art that the specific embodiments below are only for illustrative purposes, and do not limit the scope of the present application in any way. In addition, in the following embodiments, unless otherwise specified, the reagents and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the following embodiments, the processing can be carried out using conditions and methods known in the art.

[0026] The present application provides a polyetherimide dielectric film containing an indane ring structure, which is obtained by polymerization and imidization reactions of a diamine monomer containing a segment represented by Formula I and a dianhydride monomer, Formula I.

[0027] The present application introduces an indane ring structure and three methyl groups into the polyetherimide, which form a large and rigid side group. This structure forms a large steric hindrance in the polymer chain, effectively inhibiting the free rotation and close packing of the molecular chain, greatly increasing the tortuosity of the charge migration path in the material, and inhibiting the formation and spread of electrical trees, thereby significantly improving the breakdown field strength.

[0028] In some embodiments of the present application, the diamine monomer containing a segment represented by Formula I includes at least one of 1-(4-aminophenyl)-1,3,3-trimethyl-2,3-dihydro-1H-inden-5-amine and 3-(4-aminophenyl)-1,1,3-trimethyl-2,3-dihydro-1H-inden-5-amine.

[0029] In some embodiments of the present application, the dianhydride monomer includes at least one of 4,4'-(4,4'-isopropyl diphenyloxy) diphthalic anhydride and 4,4'-(hexafluoroisopropyl) diphthalic anhydride.

[0030] In some embodiments of the present application, when the dianhydride monomers include 4,4'-(4,4'-isopropyl diphenyloxy) diphthalic anhydride and 4,4'-(hexafluoroisopropyl) diphthalic anhydride, the molar ratio of the 4,4'-(4,4'-isopropyl diphenyloxy) diphthalic anhydride and 4,4'-(hexafluoroisopropyl) diphthalic anhydride is 1:0-4, and can be 1:0.3, 1:1, 1:3, 1:4, etc. In the present application, the introduction of the fluorine-containing dianhydride monomer increases the dipole interaction, aiming to utilize the strong electronegativity to bind the charge transport and increase the free volume, effectively inhibiting the migration of the carriers and the accumulation of the space charge under high electric field, thereby significantly reducing the loss and improving the efficiency. The fluorine-containing dianhydride monomer in the above ratio range not only can reduce the loss and improve the efficiency, but also can ensure that the obtained thin film has good film forming performance. Too much fluorine-containing dianhydride monomer will make the film forming performance of the obtained polyetherimide dielectric thin film worse and the brittleness larger, and an applicable dielectric thin film cannot be obtained.

[0031] In some embodiments of the present application, the molar ratio of the diamine monomer and the dianhydride monomer is 1-1.02:1, and can be 1:1, 1.01:1, 1.02:1, etc.

[0032] In some embodiments of the present application, the thickness of the polyetherimide dielectric thin film containing the indane ring structure is 9-25 μm, and can be 10 μm, 11 μm, 20 μm, 25 μm, etc.

[0033] The present application also provides a preparation method of the polyetherimide dielectric thin film containing the indane ring structure according to any one of the above technical solutions, comprising the following steps: The diamine monomer containing the segment shown in Formula I, the dianhydride monomer and the solvent are mixed to perform a polymerization reaction to obtain a polyamic acid solution, Formula I After the polyamic acid solution is sequentially subjected to bubble removal and film forming, an imidization reaction is performed to obtain the polyetherimide dielectric thin film containing the indane ring structure.

[0034] The present application first mixes the diamine monomer containing the segment shown in Formula I, the dianhydride monomer and the solvent to perform a polymerization reaction to obtain a polyamic acid solution. In the present application, the diamine monomer and the dianhydride monomer perform a polymerization reaction to generate a polyamic acid solution.

[0035] The mixing manner is not particularly limited in the present application, and the three can be mixed uniformly, that is, one monomer can be dissolved in a solvent, and then another monomer can be added, or all the monomers can be added into the solvent at the same time, or the dianhydride monomer and the diamine monomer can be dissolved in solvents respectively, and then one solution can be added into another solution; in the embodiments of the present application, the dianhydride monomer and the diamine monomer are dissolved in solvents respectively to obtain a dianhydride monomer solution and a diamine monomer solution, and then the diamine monomer solution is added dropwise into the dianhydride monomer solution.

[0036] In some embodiments of the present application, the solvent comprises at least one of N-methylpyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and m-phenol.

[0037] In some embodiments of the present application, the total mass of the diamine monomer and the dianhydride monomer containing the segment represented by formula I accounts for 10-20 wt% of the mass of the mixed solution of the diamine monomer, the dianhydride monomer and the solvent containing the segment represented by formula I, and specifically can be 11 wt%, 13 wt%, 15 wt%, 18 wt%, 20 wt% and the like. In the present application, the above percentage can further ensure that the obtained polyamic acid solution has a suitable viscosity, which is beneficial to film formation.

[0038] In some embodiments of the present application, the polymerization reaction is carried out at room temperature, and the polymerization reaction time is 24-30 h, and specifically can be 24 h, 26 h, 28 h, 30 h and the like. After the polymerization reaction, a viscous polyamic acid solution is obtained.

[0039] After obtaining the polyamic acid solution, the polyamic acid solution is subjected to bubble removal and film formation in sequence, and then subjected to imidization reaction to obtain a polyetherimide dielectric film containing an indane ring structure.

[0040] The bubble removal and film formation manner are not particularly limited in the present application, and conventional liquid bubble removal (such as vacuum bubble removal) and film formation manner (such as coating on a substrate) can be used.

[0041] In some embodiments of the present application, the film formation is that the polyamic acid solution after bubble removal is coated on a substrate in an atmosphere at 65-75℃ (and specifically can be 65℃, 70℃, 75℃ and the like), and then is incubated at 65-75℃ (and specifically can be 65℃, 70℃, 75℃ and the like) for 10-15 min, which can promote film leveling and solvent evaporation to form a shaped film.

[0042] In some embodiments of the present application, the imidization reaction is carried out under a gradient temperature program, which is sequentially incubating at 80-90℃ (specifically, 80℃, 85℃, 90℃, etc.) for 0.5-0.8 h (specifically, 0.5 h, 0.8 h, etc.), at 105-115℃ (specifically, 105℃, 110℃, 115℃, etc.) for 0.5-0.8 h (specifically, 0.5 h, 0.8 h, etc.), at 150-170℃ (specifically, 150℃, 160℃, 170℃, etc.) for 0.8-1.2 h (specifically, 0.8 h, 1.0 h, 1.2 h, etc.), at 190-210℃ (specifically, 190℃, 200℃, 210℃, etc.) for 0.8-1.2 h (specifically, 0.8 h, 1.0 h, 1.2 h, etc.), at 215-225℃ (specifically, 215℃, 220℃, 225℃, etc.) for 0.8-1.2 h (specifically, 0.8 h, 1.0 h, 1.2 h, etc.), at 250-270℃ (specifically, 250℃, 260℃, 270℃, etc.) for 0.8-1.2 h (specifically, 0.8 h, 1.0 h, 1.2 h, etc.), at 290-300℃ (specifically, 290℃, 300℃, etc.) for 0.8-1.2 h (specifically, 0.8 h, 1.0 h, 1.2 h, etc.), preferably, the gradient temperature program is incubating at 80℃ for 0.5 h, at 110℃ for 0.5 h, at 160℃ for 1 h, at 200℃ for 1 h, at 220℃ for 1 h, at 260℃ for 1 h, and at 300℃ for 1 h. The present application does not have special requirements for the heating rate to each stage.

[0043] In some embodiments of the present application, in order to apply the film, after the imidization reaction is completed to obtain the polyimide dielectric film, the polyimide dielectric film is naturally cooled to room temperature, and then peeled off from the substrate for application; the present application does not have special limitations on the peeling method, and a conventional peeling method can be used, such as soaking in warm water (e.g., 60℃) for peeling, and then drying for application.

[0044] The present application also provides the application of the indane ring-containing polyetherimide dielectric film in a dielectric capacitor, especially in a dielectric capacitor in a high-temperature (100-200℃, even 100-250℃) application environment, which is the indane ring-containing polyetherimide dielectric film according to any one of the above technical solutions or obtained by the preparation method according to any one of the above technical solutions.

[0045] The technical solutions in the present application will be described clearly and completely below in combination with the drawings and examples. The examples of the present application are only for illustration, and all other examples obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0046] Example 1 (1) 0.4 mmol of a diamine monomer (1-(4-aminophenyl)-1,3,3-trimethyl-2,3-dihydro-1H-inden-5-amine) was dissolved in 1.0 mL of N-methylpyrrolidone to obtain a diamine solution; 0.4 mmol of a dianhydride monomer (4,4'-(4,4'-isopropyl diphenyloxy) diphthalic anhydride) was dissolved in 1.26 mL of N-methylpyrrolidone to obtain a dianhydride solution, wherein the total mass of the diamine monomer and the dianhydride monomer accounted for 13 wt% of the total mass of the diamine solution and the dianhydride solution.

[0047] (2) The diamine solution was added dropwise to the dianhydride solution, and then polymerization was carried out under stirring for 24 h to obtain a polyamic acid solution.

[0048] (3) After the polyamic acid solution was degassed under vacuum, the degassed polyamic acid solution was coated on a glass plate in an oven at 70°C, and then dried at 70°C for 10 min, and then sequentially heated to 80°C for 0.5 h, 110°C for 0.5 h, 160°C for 1 h, 200°C for 1 h, 220°C for 1 h, and 260°C for 1 h, and 300°C for 1 h to obtain an indenyl-containing polyetherimide dielectric film with a thickness of 10 μm on the glass plate, which was recorded as IPEI (structure as shown in Figure 1 ).

[0049] Example 2 (1) 0.4 mmol of a diamine monomer (1-(4-aminophenyl)-1,3,3-trimethyl-2,3-dihydro-1H-inden-5-amine) was dissolved in 1.0 mL of N-methylpyrrolidone to obtain a diamine solution; 0.4 mmol of a dianhydride monomer (4,4'-(4,4'-isopropyl diphenyloxy) diphthalic anhydride and 4,4'- (hexafluoroisopropyl) diphthalic anhydride, molar ratio 3:1) was dissolved in 0.92 mL of N-methylpyrrolidone to obtain a dianhydride solution, wherein the total mass of the diamine monomer and the dianhydride monomer accounted for 13 wt% of the total mass of the diamine solution and the dianhydride solution.

[0050] (2)-(3) An indenyl-containing polyetherimide dielectric film was prepared according to the method of steps (2)-(3) in Example 1, with a thickness of 11 μm, which was recorded as 25HF-PI.

[0051] Example 3 The polyetherimide dielectric film containing indane ring structure was prepared according to the method of Example 2, except that 4,4'-(4,4'-isopropyl diphenyloxy) diphthalic anhydride and 4,4'-(hexafluoroisopropyl) diphthalic anhydride were used in a molar ratio of 1:1, and the total mass of diamine monomers and dianhydride monomers accounted for 15 wt% of the total mass of diamine solution and dianhydride solution, and the thickness of the obtained polyetherimide dielectric film containing indane ring structure was 11 μm, which was recorded as 50HF-PI (structure as shown in Figure 1 ).

[0052] Example 4 The polyetherimide dielectric film containing indane ring structure was prepared according to the method of Example 2, except that 4,4'-(4,4'-isopropyl diphenyloxy) diphthalic anhydride and 4,4'-(hexafluoroisopropyl) diphthalic anhydride were used in a molar ratio of 1:3, and the total mass of diamine monomers and dianhydride monomers accounted for 15 wt% of the total mass of diamine solution and dianhydride solution, and the thickness of the obtained polyetherimide dielectric film containing indane ring structure was 11 μm, which was recorded as 75HF-PI.

[0053] Comparative Example 1 The polyetherimide dielectric film was prepared according to the method of Example 1, except that 1,4-phenylenediamine was used as the diamine monomer, and the thickness of the obtained polyetherimide dielectric film was 10 μm, which was recorded as PEI (structure as shown in Figure 1 ).

[0054] The performance of the obtained film was tested, and after the imidization reaction was completed, the polyetherimide dielectric film was naturally cooled to room temperature, then the film was peeled off in warm water, and then placed in a drying oven at 80°C for 24 h, and then applied or tested for performance.

[0055] The Fourier transform infrared spectra of the films obtained in Examples 1-4 and Comparative Example 1 were tested, and the results are shown in Figure 2 . Figure 2 The characteristic peak at 1780 cm -1 is attributed to the C=O group, and the characteristic peak at 1380 cm -1 is attributed to the C=N group, and it can be seen from Figure 2 that the films obtained in Examples 1-4 and Comparative Example 1 all contain imide ring structure, and the imidization is complete.

[0056] The X-ray diffraction patterns of the films obtained in Examples 1-4 and Comparative Example 1 were tested, and the results are shown in Figure 3 . Figure 3In the peak that appears around 25°, it is a characteristic peak of π-π packing. From PEI to 75HF-PI, the peak position gradually weakens, indicating that π-π packing weakens and the molecular chain packing changes from tight π-π packing to more open inter-chain ordered packing, thereby increasing the molecular chain spacing, hindering charge transport, and increasing the breakdown field strength.

[0057] The differential scanning calorimetry (DSC) curves of the thin films obtained in Examples 1-4 and Comparative Example 1 were tested using a differential scanning calorimeter. The results are as follows: Figure 4 As shown. By Figure 4 It can be concluded that the glass transition temperatures of the polyetherimide dielectric films obtained in Examples 1-4 are 251.15℃, 264.48℃, 275.43℃ and 291.59℃, respectively, which are all significantly higher than those of the film obtained in Comparative Example 1 (239.26℃), indicating that they can all work stably under higher temperature conditions. The three fluorine-containing components can even work stably at 250℃. In addition, the glass transition temperatures of the films obtained in Examples 2-4 are significantly higher than those of the film obtained in Example 1, indicating that the introduction of fluorine further improves the thermodynamic stability of the film.

[0058] The fluorescence emission spectra of the films obtained in Examples 1, 3 and Comparative Example 1 at room temperature were tested, and the results are as follows: Figure 5 As shown. By Figure 5 It can be seen that, compared with the PEI obtained in Comparative Example 1, the peak positions of the films obtained in Examples 1 and 3 have shifted to the left (i.e., blue shift occurred), and the fluorescence intensity has increased, and the peak shape is sharper. This indicates that the π-π stacking in the polyetherimide film provided by the present invention is weakened, and the intra-chain / inter-chain electron transfer is suppressed. It can be seen that the twisted non-planar indene structure introduces steric hindrance, which weakens charge transport and is beneficial to increasing the breakdown field strength.

[0059] The electrical properties of the thin films obtained in Examples 1-4 and Comparative Example 1 were tested using the following method: Metal photomasks with a circular aperture diameter of 3 mm were prepared. The prepared thin film was sandwiched between two metal photomasks, and gold electrodes were symmetrically sputtered onto the upper and lower surfaces at a sputtering current of 30 mA for 300 s. Dielectric spectrum, dielectric temperature spectrum, breakdown field strength, and energy storage performance were tested using an impedance analyzer and a ferroelectric workstation.

[0060] The dielectric temperature spectra of the films obtained in Examples 1-4 and Comparative Example 1 were tested, and the results are as follows: Figure 6 As shown. By Figure 6It can be seen that the room temperature dielectric constants (1kHz) of the films obtained in Examples 1-4 and Comparative Example 1 are 3.097, 3.027, 2.971, 2.952 and 3.101, respectively, and the dielectric constants (1kHz) at 200℃ are 2.907, 2.833, 2.832, 2.824 and 2.920, respectively. This indicates that the dielectric film provided by the present invention has a relatively stable dielectric constant as the temperature increases, and maintains a high level. The introduction of the indene ring structure and fluorine-containing groups does not have a significant negative impact on the dielectric constant, and also has a small loss tangent value.

[0061] The breakdown field strength of the films obtained in Examples 1-4 and Comparative Example 1 at 150°C and 200°C was tested, and the results are as follows: Figure 7 As shown, (a) is the Weber distribution at 150℃, and (b) is the Weber distribution at 200℃. Figure 7 It can be seen that the breakdown field strengths of the films obtained in Examples 1-4 and Comparative Example 1 at 150°C are 645.98 kV / mm, 650.88 kV / mm, 678.35 kV / mm, 666.56 kV / mm, and 524.11 kV / mm, respectively, and the breakdown field strengths at 200°C are 606.52 kV / mm, 618.22 kV / mm, 651.82 kV / mm, 647.23 kV / mm, and 518.73 kV / mm, respectively. It is evident that the film provided by the present invention exhibits at least a 23.25% increase in breakdown field strength compared to the film obtained in Comparative Example 1 at 150°C, and at least a 16.92% increase at 200°C compared to the film obtained in Comparative Example 1, indicating that the introduction of the indene ring structure improves the breakdown field strength.

[0062] The energy storage performance of the thin films obtained in Examples 1-4 and Comparative Example 1 at 200°C and 250°C was tested, and the results are as follows: Figure 8 As shown, (a) presents the energy storage performance test results of the films obtained in Examples 1-4 and Comparative Example 1 at 200°C, and (b) presents the energy storage performance test results of the films obtained in Examples 2-4 at 250°C. Figure 8 As can be seen from (a) in the figure, the discharge energy densities of the films obtained in Examples 1-4 and Comparative Example 1 at 200°C with a storage efficiency of 90% are 3.35 J / cm². 3 2.93 J / cm 3 4.38 J / cm 3 3.49 J / cm 3 1.66 J / cm 3 The maximum discharge energy density is 4.53 J / cm³. 3 5.09 J / cm 3 5.92 J / cm3 , 5.41 J / cm 3 , 2.65 J / cm 3 . It can be seen that the high-temperature energy storage performance of the thin films obtained in Examples 1-4 is greatly improved compared with Comparative Example 1, especially the discharge energy density of the thin film obtained in Example 3 is increased by 163.8% at the energy storage efficiency of 90%. It can be seen from (b) in Table 1 that the discharge energy density of the thin films obtained in Examples 2-4 at 250℃ is 1.74 J / cm Figure 8 , 2.81 J / cm 3 , 3.65 J / cm 3 , 3.41, 3.98, 4.84 J / cm 3 , respectively, at the energy storage efficiency of 90%, and the maximum discharge energy density is 3.41, 3.98, 4.84 J / cm 3 , respectively. It can be seen that the polyetherimide dielectric thin film provided by the present application containing indane ring structure and fluorine-containing group at the same time still has a high discharge energy density at 250℃, and can be stably operated at 250℃.

[0063] Although the preferred embodiments of the present application have been shown and described, it is conceivable that those skilled in the art can design various modifications of the present application within the spirit and scope of the appended claims.

Claims

1. A polyetherimide dielectric film containing an indane ring structure, obtained by polymerization and imidization of a diamine monomer containing a segment represented by Formula I and a dianhydride monomer, wherein the diamine monomer containing the segment represented by Formula I comprises at least one of 1-(4-aminophenyl)-1, 3, 3-trimethyl-2, 3-dihydro-1H-inden-5-amine and 3-(4-aminophenyl)-1, 1, 3-trimethyl-2, 3-dihydro-1H-inden-5-amine; and the dianhydride monomer comprises at least one of 4, 4'-(4, 4'-isopropyl diphenyloxy) diphthalic anhydride and 4, 4'-(hexafluoroisopropyl) diphthalic anhydride. Formula I.

2. The indane ring-containing polyetherimide dielectric film of claim 1, wherein, When the dianhydride monomer comprises 4, 4'-(4, 4'-isopropyl diphenyloxy) diphthalic anhydride and 4, 4'-(hexafluoroisopropyl) diphthalic anhydride, the molar ratio of the 4, 4'-(4, 4'-isopropyl diphenyloxy) diphthalic anhydride to the 4, 4'-(hexafluoroisopropyl) diphthalic anhydride is 1:0-4.

3. The indane ring-containing polyetherimide dielectric film of claim 1, wherein, The polyetherimide dielectric film containing the indane ring structure has a thickness of 9-25 μm.

4. The indane ring-containing polyetherimide dielectric film of claim 3, wherein, 6.A method for preparing the polyetherimide dielectric film containing the indane ring structure according to any one of claims 1-5, comprising the following steps: mixing the diamine monomer containing the segment represented by Formula I, the dianhydride monomer and a solvent to perform polymerization, thereby obtaining a polyamic acid solution, 5. The indane ring-containing polyetherimide dielectric film of any one of claims 1-4, wherein, performing imidization on the polyamic acid solution after sequentially performing bubble removal and film formation, thereby obtaining the polyetherimide dielectric film containing the indane ring structure. The solvent comprises at least one of N-methyl pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide and m-cresol. The total mass of the diamine monomer containing the segment represented by Formula I and the dianhydride monomer accounts for 10-20 wt% of the mass of the mixed solution obtained by mixing the diamine monomer containing the segment represented by Formula I, the dianhydride monomer and the solvent. Formula I The polymerization is performed at room temperature, and the polymerization time is 24-30 h.

7. The production method according to claim 6, wherein The imidization is performed under a gradient temperature program, and the gradient temperature program comprises sequentially maintaining at 80-90℃ for 0.5-0.8 h, at 105-115℃ for 0.5-0.8 h, at 150-170℃ for 0.8-1.2 h, at 190-210℃ for 0.8-1.2 h, at 215-225℃ for 0.8-1.2 h, at 250-270℃ for 0.8-1.2 h and at 290-300℃ for 0.8-1.2 h. 10.Use of the polyetherimide dielectric film containing the indane ring structure according to any one of claims 1-5 or the polyetherimide dielectric film containing the indane ring structure obtained by the preparation method according to any one of claims 6-9 in a dielectric capacitor.

8. The production method according to claim 6 or 7, characterized by, ​ 9. The preparation method according to claim 6, characterized in that, ​ ​

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