Gema-mma copolymer dielectric film and its preparation method and application

Abstract

The application discloses a GEMA-MMA copolymer dielectric film and a preparation method and application thereof, and belongs to the technical field of polymer-based dielectric materials. The preparation method of the application adopts a biomass raw material guaiacol (GA) with lignin as a source, and methyl guaiacol methacrylate (GEMA) is prepared through an esterification reaction; GEMA and methyl methacrylate (MMA) are copolymerized to obtain the GEMA-MMA copolymer dielectric film, the polarization strength and the breakdown strength can be effectively improved, and the energy storage density of the polymer is more effectively improved. The preparation method is simple and has good repeatability, the breakdown strength and the energy storage density can be improved by controlling the molar ratio of the GEMA and the MMA copolymerization, the energy storage efficiency of the polymer is increased, and the breakdown strength and the energy storage density of the film capacitor can be improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer-based dielectric materials technology, specifically relating to a GEMA-MMA copolymer dielectric film, its preparation method, and its application. Background Technology

[0002] In recent years, the effective utilization and storage of various energy sources has become a hot research topic. As a physical energy storage device, polymer film capacitors have advantages such as ultra-high power density and the ability to store and release energy very quickly. They are widely used in fields such as capacitors, pulse power technology and electric vehicle technology.

[0003] Currently, biaxially oriented polypropylene (BOPP) film is the most widely used in commercially available film capacitors. It has very high breakdown strength, but its energy storage density is very low, only 2–4 J / cm³. 3 Polyvinylidene fluoride (PVDF) and its copolymers are nonlinear dielectrics. Compared to other materials, they possess a very high dielectric constant and have been extensively studied. However, their high polarization loss and poor charge / discharge efficiency limit their application in dielectric energy storage. Guaiacin, also known as 2-methoxyphenol, is a natural organic compound with a distinctive aroma, widely used in fragrances and pharmaceuticals. However, its application in electronic materials is limited. Functional modification of guaiacin shows potential for use in dielectric materials. The guaiacin molecule contains polar phenolic hydroxyl groups, allowing for modification through organic synthesis to prepare polymerizable monomers with guaiacin structures. The presence of benzene rings and ester groups provides structural advantages, and the δ-π bond interactions enhance energy storage density and reduce energy loss.

[0004] Polymethyl methacrylate (PMMA) is a common organic polymer, also known as plexiglass, and can be used as a linear dielectric material. However, PMMA has relatively low breakdown strength, and the ester groups in the PMMA molecular chain are polar groups. Strong coupling forces between adjacent polar groups can lead to relaxation and thus high dielectric loss, resulting in low energy storage density and limiting its application in the dielectric field. Therefore, modification studies are needed to improve its energy storage density. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a GEMA-MMA copolymer dielectric film, its preparation method and application, so as to solve the problem that the dielectric loss of existing methyl methacrylate is large, resulting in low energy storage density.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] This invention discloses a method for preparing a GEMA-MMA copolymer dielectric thin film, comprising the following steps:

[0008] 1) Guaiacin, methacrylic anhydride and esterifying agent are mixed evenly and reacted under an inert atmosphere. After cooling to room temperature, the mixture is diluted with dichloromethane, washed, and freeze-dried to obtain GEMA.

[0009] 2) Methyl methacrylate and GEMA obtained in step 1) are dissolved in DMF, an initiator is added, and the mixture is reacted under an inert atmosphere. After purification, heating and drying, a GEMA-MMA copolymer dielectric film is obtained.

[0010] Preferably, in step 2), the molar ratio of GEMA to methyl methacrylate is 1:(6-10).

[0011] Preferably, in step 2), the inert atmosphere is argon, the reaction temperature is 80°C, and the reaction time is 12 hours.

[0012] Preferably, in step 2), the product is purified by methanol precipitation and heated at 80°C for 12 hours.

[0013] Preferably, in step 1), the molar ratio of guaiacol to methacrylic anhydride is 2:2:1.

[0014] Preferably, in step 1), the esterifying agent is DMAP, and the molar percentage of DMAP is 2 mol%.

[0015] Preferably, in step 1), the inert atmosphere is argon, and the reaction time is 24 hours.

[0016] Preferably, in step 1), the washing conditions are as follows: washing sequentially with saturated NaHCO3 aqueous solution, 1 mol / L NaOH aqueous solution, 0.5 mol / L NaOH aqueous solution, 1.0 mol / L HCl aqueous solution and deionized water.

[0017] The present invention also discloses a GEMA-MMA copolymer dielectric film prepared by the above-described method, wherein the GEMA-MMA copolymer dielectric film has a thickness of 5–15 μm, an electrical breakdown strength of 911.2–638.6 MV / m, and a storage density of 8.0–9.0 J / cm³. 3 The energy efficiency is 87.5%–92%.

[0018] The present invention also discloses the application of the above-mentioned GEMA-MMA copolymer dielectric film in the preparation of metallized film capacitors.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention discloses a method for preparing a GEMA-MMA copolymer dielectric film. Using biomass guaiacol (GA) as a raw material, guaiacol methacrylate (GEMA) is prepared by esterification with methacrylic anhydride. The introduction of a benzene ring into GEMA reduces the strong coupling force between adjacent polar groups, thereby reducing the high dielectric loss caused by relaxation and improving the low energy density of PMMA. The GEMA-MMA copolymer dielectric film is obtained by copolymerizing guaiacol methacrylate (GEMA) and methyl methacrylate (MMA). By introducing flexible segments into the rigid structure of the polar aromatic polymer, the flexibility and dipole polarization of the dipoles are increased at the molecular level, effectively improving the polarization intensity and breakdown strength of the obtained GEMA-MMA copolymer dielectric film, and thus more effectively improving its energy density. The entire preparation method is simple and has good reproducibility.

[0021] Furthermore, by controlling the ratio of GEMA to MMA, the breakdown strength and energy storage density of the GEMA-MMA copolymer dielectric film can be further improved, thereby increasing the energy storage efficiency of the polymer.

[0022] Furthermore, conducting the reaction under an argon atmosphere can effectively remove oxygen from the bottle;

[0023] Furthermore, purification by methanol precipitation can effectively remove impurities from the solvent, yielding a pure GEMA-MMA copolymer dielectric film.

[0024] The present invention also discloses a GEMA-MMA copolymer dielectric film prepared by the above-described method, wherein the thickness of the GEMA-MMA copolymer dielectric film is 5–15 μm, the breakdown strength of the dielectric film is 911.2–638.6 MV / m, and the energy storage density is 8.0–9.0 J / cm². 3 With an energy efficiency of 87.5% to 92%, it can effectively improve the breakdown strength and energy storage density of film capacitors.

[0025] This invention also discloses the application of the above-mentioned GEMA-MMA copolymer dielectric film in the preparation of metallized film capacitors. Firstly, the most widely used commercially available metallized film capacitor is the BOPP film capacitor, which has a very low energy density, approximately only 2–3 J / cm². 3 The present invention significantly improves the energy storage density and energy storage efficiency of the GEMA-MMA copolymer dielectric film. Secondly, PVDF-based polymers and BOPP polymers, which are widely used in dielectric materials, are all non-renewable and non-biodegradable petroleum-derived synthetic polymers. The present invention utilizes guaiacol, an environmentally friendly biomass material, to modify it and prepare a dielectric film, which has long-term significance for environmental protection. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the GEMA preparation process according to the present invention;

[0027] Figure 2 This is a schematic diagram illustrating the preparation of the GEMA-MMA copolymer dielectric film of the present invention;

[0028] Figure 3 For the GEMA-MMA copolymer dielectric films with different molar ratios of the present invention 1 Schematic diagram of H NMR spectrum;

[0029] Figure 4 This is a schematic diagram of the FT-IR spectra of GEMA-MMA copolymer dielectric films with different molar ratios according to the present invention;

[0030] Figure 5 This is a schematic diagram of the electric displacement-electric field (DE) curve of the GEMA-MMA copolymer dielectric film (GEMA:MMA molar ratio of 1:9) prepared in Example 2 of the present invention. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0033] The present invention will now be described in further detail with reference to the accompanying drawings:

[0034] This invention provides a GEMA-MMA copolymer dielectric film and its preparation method. First, guaiacol (GA) is used as a raw material to prepare guaiacol methacrylate (GEMA) through an esterification reaction. Then, it is polymerized with methyl methacrylate (MMA) in different molar ratios to prepare guaiacol methacrylate-methyl methacrylate copolymer dielectric films (GEMA-MMA copolymer dielectric films) with different ratios. The electrical breakdown strength and energy storage performance of the GEMA-MMA copolymer dielectric films with different ratios were investigated.

[0035] A method for preparing a GEMA-MMA copolymer dielectric film specifically includes the following steps:

[0036] (1) Add 24.8 g of GA, 0.35 g of DMAP (2 mol%), and 15.4 g of methacrylic anhydride to a three-necked flask. Seal the flask and purge with argon gas for 1 h. Then place the flask in a silicone oil bath at 45 °C and stir mechanically for 24 h. Immediately afterwards, allow the mixture to cool to room temperature and dilute with dichloromethane. Then wash successively with saturated NaHCO3 aqueous solution, 1 mol / L NaOH aqueous solution, 0.5 mol / L NaOH aqueous solution, 1.0 mol / L HCl aqueous solution, and deionized water. Finally, freeze-dry to obtain GEMA.

[0037] (2) Dissolve 0.58g of GEMA and 1.5-3g of MMA in DMF, add 0.008-0.01g of AIBN, seal the small bottle and purge with argon for 1h, then stir magnetically. After 12h, place the mixed solution in methanol to precipitate, then heat at 80℃ for 12h, and dry the solvent to obtain the GEMA-MMA copolymer dielectric film.

[0038] Example 1

[0039] A method for preparing a GEMA-MMA copolymer dielectric film specifically includes the following steps:

[0040] (1) Add 24.8 g of GA, 0.35 g of DMAP (2 mol%), and 15.4 g of methacrylic anhydride to a three-necked flask. Seal the flask and purge with argon gas for 1 h. Then place the flask in a silicone oil bath at 45 °C and stir mechanically for 24 h. Immediately afterwards, allow the mixture to cool to room temperature and dilute with dichloromethane. Then wash successively with saturated NaHCO3 aqueous solution, 1 mol / L NaOH aqueous solution, 0.5 mol / L NaOH aqueous solution, 1.0 mol / L HCl aqueous solution, and deionized water. Finally, freeze-dry to obtain GEMA.

[0041] (2) Dissolve 0.58 g of GEMA and 3 g of MMA in DMF, add 0.01 g of AIBN, seal the vial, and purge with argon gas for 1 hour. Then, magnetically stir the solution for 12 hours. After precipitating the mixture in methanol, heat it at 80°C for 12 hours. The film is then dried and detached from deionized water to obtain the GEMA-MMA copolymer dielectric film. This GEMA-MMA copolymer dielectric film has a thickness of 5 μm, a maximum electrical breakdown strength of 775 MV / m, and a storage density of 8.4 J / cm² when the electric field strength is 550 MV / m. 3 Energy efficiency can reach 88%.

[0042] Example 2

[0043] A method for preparing a GEMA-MMA copolymer dielectric film specifically includes the following steps:

[0044] (1) Add 24.8 g of GA, 0.35 g of DMAP (2 mol%), and 15.4 g of methacrylic anhydride to a three-necked flask. Seal the flask and purge with argon gas for 1 h. Then place the flask in a silicone oil bath at 45 °C and stir mechanically for 24 h. Immediately afterwards, allow the mixture to cool to room temperature and dilute with dichloromethane. Then wash successively with saturated NaHCO3 aqueous solution, 1 mol / L NaOH aqueous solution, 0.5 mol / L NaOH aqueous solution, 1.0 mol / L HCl aqueous solution, and deionized water. Finally, freeze-dry to obtain GEMA.

[0045] (2) Dissolve 0.58 g of GEMA and 2.7 g of MMA in DMF, add 0.01 g of AIBN, seal the vial, and purge with argon gas for 1 hour. Then, stir magnetically. After 12 hours, precipitate the mixture in methanol, then heat at 80°C for 12 hours. Afterward, dry the film and detach it in deionized water to obtain the GEMA-MMA copolymer dielectric film. The GEMA-MMA copolymer dielectric film has a thickness of 9 μm, a maximum electrical breakdown strength of 911.2 MV / m, and a storage density of 9.0 J / cm² at an electric field strength of 550 MV / m. 3 The energy efficiency can reach 92%.

[0046] See Figure 3 For the GEMA-MMA copolymer dielectric films with different molar ratios of the present invention 1 Schematic diagram of HNMR spectrum; as can be seen from the figure, through 1¹H NMR determined the chemical structure of the GEMA-MMA copolymer dielectric film, as shown in the figure. The NMR peaks δ = 0.8-1.9 ppm represent hydrogen atoms on the methyl and methylene groups of the main chain and side chain of the GEMA-MMA copolymer dielectric film; the NMR peaks δ = 3.6-3.9 ppm represent hydrogen atoms on the methoxy groups of GEMA and MMA on the GEMA-MMA copolymer dielectric film; and the NMR peaks δ = 6.94-7.3 ppm correspond to hydrogen atoms on the benzene ring. This indicates that GEMA and MMA were successfully copolymerized in this reaction, and the GEMA-MMA copolymer dielectric film was successfully prepared.

[0047] See Figure 4 This is a schematic diagram of the FT-IR spectra of GEMA-MMA with different proportions according to the present invention; wherein, the GEMA:MMA molar ratio of 1:6 is the GEMA-MMA copolymer dielectric film prepared in Example 5 of the present invention, the GEMA:MMA molar ratio of 1:7 is the GEMA-MMA copolymer dielectric film prepared in Example 4 of the present invention, the GEMA:MMA molar ratio of 1:8 is the GEMA-MMA copolymer dielectric film prepared in Example 3 of the present invention, the GEMA:MMA molar ratio of 1:9 is the GEMA-MMA copolymer dielectric film prepared in Example 2 of the present invention, and the GEMA:MMA molar ratio of 1:10 is the GEMA-MMA copolymer dielectric film prepared in Example 1 of the present invention. As can be seen from the figure, the 1640 cm⁻¹ of the GEMA-MMA copolymer dielectric film... -1 The absorption peak at the C=C junction of the olefin disappears, and the peak at 1607 cm⁻¹ disappears. -1 An absorption peak for the unsaturated C=C ring of benzene ring appeared, and it was observed at 3075 cm⁻¹. -1 An absorption peak for the CH stretching vibration of the benzene ring appeared; 1750 cm⁻¹ -1 The presence of the ester group absorption peak indicates that GEMA and MMA were successfully copolymerized in this reaction, and the GEMA-MMA copolymer dielectric film was successfully prepared.

[0048] See Figure 5 This is a schematic diagram of the electric displacement-electric field (DE) curve of the GEMA-MMA copolymer dielectric film (GEMA:MMA molar ratio of 1:9) prepared in Embodiment 2 of the present invention. As can be seen from the figure, the external electric field strength is applied starting from 100 MV / m and gradually increases in increments of 50 MV / m until the film is broken down. In the first quadrant, the highest point on the hysteresis loop gradually rises with increasing electric field strength, and the area enclosed by the hysteresis loop and the coordinate axes also increases. This indicates that with increasing electric field strength, the polarization intensity of the polymer film increases, and energy loss becomes more severe. The GEMA-MMA copolymer dielectric film has a storage density of 9.0 J / cm³ at an electric field strength of 550 MV / m. 3 .

[0049] Example 3

[0050] A method for preparing a GEMA-MMA copolymer dielectric film specifically includes the following steps:

[0051] (1) Add 24.8 g of GA, 0.35 g of DMAP (2 mol%), and 15.4 g of methacrylic anhydride to a three-necked flask. Seal the flask and purge with argon gas for 1 h. Then place the flask in a silicone oil bath at 45 °C and stir mechanically for 24 h. Immediately afterwards, allow the mixture to cool to room temperature and dilute with dichloromethane. Then wash successively with saturated NaHCO3 aqueous solution, 1 mol / L NaOH aqueous solution, 0.5 mol / L NaOH aqueous solution, 1.0 mol / L HCl aqueous solution, and deionized water. Finally, freeze-dry to obtain GEMA.

[0052] (2) Dissolve 0.58 g of GEMA and 2.4 g of MMA in DMF, add 0.009 g of AIBN, seal the vial, and purge with argon gas for 1 hour. Then, magnetically stir the solution for 12 hours. Afterward, precipitate the mixture in methanol, then heat at 80°C for 12 hours. Finally, dry the film and detach it in deionized water to obtain the GEMA-MMA copolymer dielectric film. This GEMA-MMA copolymer dielectric film has a thickness of 10 μm, a maximum electrical breakdown strength of 762.3 MV / m, and a storage density of 8.7 J / cm² at an electric field strength of 550 MV / m. 3 The energy efficiency can reach 91%.

[0053] Example 4

[0054] A method for preparing a GEMA-MMA copolymer dielectric film specifically includes the following steps:

[0055] (1) Add 24.8 g of GA, 0.35 g of DMAP (2 mol%), and 15.4 g of methacrylic anhydride to a three-necked flask. Seal the flask and purge with argon gas for 1 h. Then place the flask in a silicone oil bath at 45 °C and stir mechanically for 24 h. Immediately afterwards, allow the mixture to cool to room temperature and dilute with dichloromethane. Then wash successively with saturated NaHCO3 aqueous solution, 1 mol / L NaOH aqueous solution, 0.5 mol / L NaOH aqueous solution, 1.0 mol / L HCl aqueous solution, and deionized water. Finally, freeze-dry to obtain GEMA.

[0056] (2) Dissolve 0.58 g of GEMA and 2.1 g of MMA in DMF, add 0.008 g of AIBN, seal the vial, and purge with argon gas for 1 hour. Then, magnetically stir the solution for 12 hours. After precipitating the mixture in methanol, heat at 80°C for 12 hours. The film is then dried and detached from deionized water to obtain the GEMA-MMA copolymer dielectric film. This GEMA-MMA copolymer dielectric film has a thickness of 15 μm, a maximum electrical breakdown strength of 650.5 MV / m, and a storage density of 8.1 J / cm² at an electric field strength of 550 MV / m. 3 The energy efficiency can reach 88.5%.

[0057] Example 5

[0058] A method for preparing a GEMA-MMA copolymer dielectric film specifically includes the following steps:

[0059] (1) Add 24.8 g of GA, 0.35 g of DMAP (2 mol%), and 15.4 g of methacrylic anhydride to a three-necked flask. Seal the flask and purge with argon gas for 1 h. Then place the flask in a silicone oil bath at 45 °C and stir mechanically for 24 h. Immediately afterwards, allow the mixture to cool to room temperature and dilute with dichloromethane. Then wash successively with saturated NaHCO3 aqueous solution, 1 mol / L NaOH aqueous solution, 0.5 mol / L NaOH aqueous solution, 1.0 mol / L HCl aqueous solution, and deionized water. Finally, freeze-dry to obtain GEMA.

[0060] (2) Dissolve 0.58 g of GEMA and 1.8 g of MMA in DMF, add 0.007 g of AIBN, seal the vial, and purge with argon gas for 1 hour. Then, stir magnetically for 12 hours. After that, precipitate the mixture in methanol, then heat at 80°C for 12 hours. Finally, dry the film and remove it from deionized water to obtain the GEMA-MMA copolymer dielectric film. The thickness of this GEMA-MMA copolymer dielectric film is 11 μm, the maximum electrical breakdown strength can reach 638.6 MV / m, and the energy storage density of the film can reach 8.0 J / cm² when the electric field strength is 550 MV / m. 3 The energy efficiency can reach 87.5%.

[0061] Comparative Example 1

[0062] 3g of MMA was dissolved in DMF, and 0.009g of AIBN was added. The bottle was sealed and argon gas was introduced for 1 hour, followed by magnetic stirring. After 12 hours, the mixture was placed in methanol to precipitate the film, which was then heated at 80℃ for 12 hours. The film was then dried and detached from deionized water to obtain a pure PMMA film. Its maximum electrical breakdown strength reached 668.2 MV / m, and the energy storage density reached 6.8 J / cm² at an electric field strength of 550 MV / m. 3 The energy efficiency can reach 83%.

[0063] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a GEMA-MMA copolymer dielectric thin film, characterized in that, Includes the following steps: 1) Guaiacin, methacrylic anhydride, and esterifying agent were mixed evenly and reacted under argon atmosphere for 24 h. After cooling to room temperature, the mixture was diluted with dichloromethane, washed, and freeze-dried to obtain GEMA. The washing conditions were as follows: sequential washing with saturated NaHCO3 aqueous solution, 1 mol / L NaOH aqueous solution, 0.5 mol / L NaOH aqueous solution, 1.0 mol / L HCl aqueous solution, and deionized water. The molar ratio of guaiaacin to methacrylic anhydride was 2:

1. The esterifying agent was DMAP, with a molar percentage of 2 mol%. 2) Methyl methacrylate and GEMA obtained in step 1) were dissolved in DMF, an initiator was added, and the mixture was reacted at 80 °C for 12 h under argon atmosphere. After purification, heating, and drying, a GEMA-MMA copolymer dielectric film was obtained. The molar ratio of GEMA to methyl methacrylate was 1:(6~10). The film was purified by methanol precipitation and heated at 80 °C for 12 h. The GEMA-MMA copolymer dielectric film has a thickness of 5–15 μm, an electrical breakdown strength of 911.2–638.6 MV / m, and a storage density of 8.0–9.0 J / cm³. 3 The energy efficiency is 87.5%~92%.

2. The GEMA-MMA copolymer dielectric film prepared by the method of claim 1, characterized in that, The GEMA-MMA copolymer dielectric film has a thickness of 5–15 μm, an electrical breakdown strength of 911.2–638.6 MV / m, and a storage density of 8.0–9.0 J / cm³. 3 The energy efficiency is 87.5%~92%.

3. The application of the GEMA-MMA copolymer dielectric film according to claim 2 in the preparation of metallized film capacitors.

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