Process for the preparation of polyetherimide films based on grafted trihydroxy aminomethane

Abstract

Disclosed is a method for preparing a polyetherimide film grafted with trihydroxy aminomethane, in which a first mass of trihydroxy aminomethane is dissolved in an aprotic polar solvent under continuous first stirring to obtain a trihydroxy aminomethane solution; a second mass of polyetherimide is dissolved in the trihydroxy aminomethane solution under continuous second stirring to obtain a trihydroxy aminomethane grafted polyetherimide solution; the trihydroxy aminomethane grafted polyetherimide solution is vacuum degassed to obtain a trihydroxy aminomethane grafted polyetherimide casting solution; the trihydroxy aminomethane grafted polyetherimide casting solution is coated on a quartz glass plate using a doctor blade, and after solvent removal through stepwise temperature increase and vacuum drying, a trihydroxy aminomethane grafted polyetherimide film is obtained.

Description

Technical Field

[0001] This invention relates to the field of energy storage dielectric materials technology, and in particular to a method for preparing polyetherimide films based on grafted trihydroxyaminomethane. Background Technology

[0002] Dielectric capacitors are the energy storage devices with the highest power density, crucial for the lightweighting and miniaturization of next-generation automotive and aerospace power systems. Organic film capacitors, with their advantages of light weight, good processability, low production cost, and high dielectric strength, are an excellent choice for energy storage applications in aerospace and electric vehicles. However, currently commercially available polymer dielectrics, such as biaxially oriented polypropylene films, are not resistant to high temperatures and electron beam irradiation in space, making them difficult to use under extreme conditions. To meet the application requirements of polymer dielectrics in extreme environments, researchers and industry both domestically and internationally have developed and produced polyetherimide materials with high glass transition temperatures and radiation resistance. However, the energy density of these materials cannot meet the growing application demands.

[0003] The preparation method and applications of cross-linked polyetherimide-based dielectric composite films utilize core-shell structured nano-ceramic particles as fillers. The surface of these fillers is organically functionalized to introduce cross-linkable functional groups, enabling the nanoparticles to cross-link with the polyetherimide matrix to form a network structure, thus solving the problems of filler dispersion and compatibility. Simultaneously, cross-linkable polyetherimide with good heat resistance and mechanical properties is used as the polymer matrix material to prepare cross-linked polyetherimide-based dielectric composite film materials with excellent dielectric properties. These films exhibit high dielectric constants and low dielectric losses at both room temperature and high temperatures. However, while these dielectric composite films possess excellent dielectric properties, the introduction of cross-linking points reduces the film's recyclability, thus limiting its recycling and reuse, which is detrimental to environmental protection.

[0004] High-Temperature Energy Storage Hybrid Polyetherimide Dielectric Thin Film, its Preparation Method, and Applications: A polyetherimide solution with hydroxyl-terminated or side-chain polyetheramic acid is synthesized by reacting polyetherimide monomers with hydroxyl functional groups. Water and metal alkoxides are then added as inorganic precursors to form a homogeneous sol. The thin film is prepared through coating and thermal imidization. This one-step synthesis method, with the introduction of an inorganic phase during hybridization, achieves molecular-level dispersion, improves the aggregation of the inorganic phase and the interfacial compatibility with the organic phase, and enhances the energy storage performance of the dielectric film at high temperatures. Although this dielectric composite film exhibits excellent dielectric energy storage performance, its preparation process is complex, and the raw materials are expensive, making it unsuitable for commercial applications.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing polyetherimide films based on grafted trihydroxyaminomethane. This method addresses the above-mentioned deficiencies or needs for improvement in the prior art, and enables the preparation of recyclable, low-cost polyetherimide films with high dielectric properties and high energy storage density.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for preparing a polyetherimide film based on grafted trihydroxyaminomethane according to the present invention includes:

[0009] Step S100: Weigh a first mass of trihydroxyaminomethane and dissolve it in an aprotic polar solvent under continuous first stirring to obtain a trihydroxyaminomethane solution.

[0010] Step S200: Weigh a second mass of polyetherimide and dissolve it in the trihydroxyaminomethane solution under continuous second stirring to obtain a trihydroxyaminomethane-grafted polyetherimide solution.

[0011] Step S300: The trihydroxyaminomethane-grafted polyetherimide solution is degassed under vacuum to obtain a trihydroxyaminomethane-grafted polyetherimide casting solution.

[0012] In step S400, the trihydroxyaminomethane-grafted polyetherimide casting solution is coated onto a quartz glass plate using a doctor blade. After removing the solvent by stepwise heating and then vacuum drying, a trihydroxyaminomethane-grafted polyetherimide film is obtained.

[0013] In the method for preparing a polyetherimide film based on grafted trihydroxyaminomethane, in step S100, 0.05-0.1g of trihydroxyaminomethane is weighed using an electronic balance, and 10ml-20ml of polar aprotic solvent is measured using a graduated cylinder at room temperature. The first stirring conditions are: stirring with a mechanical stirrer at room temperature to 50℃, under a nitrogen atmosphere and at a speed of 100-500r / min for 0.5-4 hours.

[0014] In the method for preparing a polyetherimide film based on grafted trihydroxyaminomethane, the nonpolar organic solvent includes dimethylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone.

[0015] In the method for preparing a polyetherimide film based on grafted trihydroxyaminomethane, in step S200, 1-2g of polyetherimide is weighed using an electronic balance, and the second stirring conditions are: a mechanical stirrer is used to stir for 2-6 hours at 60-80℃, under a nitrogen atmosphere and at a speed of 100r / min-1000r / min.

[0016] In the method for preparing a polyetherimide film based on grafted trihydroxyaminomethane, in step S300, the trihydroxyaminomethane-grafted polyetherimide solution obtained from the reaction is degassed in a vacuum oven. The degassed temperature is controlled at 25-40℃ and the pressure is below 10Pa. The degassed process is continued for 1-2 hours to obtain a trihydroxyaminomethane-grafted polyetherimide casting solution.

[0017] In the method for preparing a polyetherimide film based on grafted trihydroxyaminomethane, the doctor blade speed is 10-20 mm / s; the step temperature is increased by holding at 60℃ for 20 minutes, holding at 90℃ for 0.5 hours, and holding at 120℃ for 1 hour. After the solvent is dried, the glass plate is transferred to a vacuum oven for further drying at 150℃-200℃ for 12-24 hours, finally obtaining a trihydroxyaminomethane-grafted polyetherimide film.

[0018] In the method for preparing a polyetherimide film based on grafted trihydroxyaminomethane, the breakdown field strength of the trihydroxyaminomethane-grafted polyetherimide film is at least 602.5 MV / m, and the dielectric constant is 3.3-3.4.

[0019] In the above technical solution, the present invention provides a method for preparing a polyetherimide film based on grafted trihydroxyaminomethane, which has the following beneficial effects: The method for preparing a polyetherimide film based on grafted trihydroxyaminomethane of the present invention involves weighing a certain mass of trihydroxyaminomethane (Tris), dissolving it in an aprotic polar solvent under continuous vigorous stirring, heating, and nitrogen purging to obtain a trihydroxyaminomethane solution; weighing a certain mass of polyetherimide (PEI), dissolving it in the trihydroxyaminomethane solution under continuous vigorous stirring, heating, and nitrogen purging to obtain a trihydroxyaminomethane-grafted polyetherimide (Tris-g-PEI) solution; vacuum degassing the obtained trihydroxyaminomethane-grafted polyetherimide solution to obtain a Tris-g-PEI casting solution; and then using a scraper to... The coating was applied to a clean quartz glass plate, and after removing the solvent by stepwise heating and vacuum drying, a Tris-g-PEI film was obtained. This invention directly links the main chains of trihydroxyaminomethane and polyetherimide through a chemical reaction. Firstly, the introduction of hydrogen bonds enhances the intermolecular interactions of polyetherimide molecules, significantly increasing the breakdown field strength from 491.6 MV / m to 602.5 MV / m. Secondly, the introduction of hydrogen bonds does not create physical cross-linking points, thus enhancing intermolecular forces without compromising recyclability; the film can be completely dissolved again with a polar aprotic solvent. Thirdly, the introduction of strongly polar hydroxyl groups increases the dielectric constant of the film from 3.1-3.15 to 3.3-3.4. Fourthly, compared to doping with inorganic nanoparticles, there is no problem with poor dispersibility, thus greatly simplifying the preparation process. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0021] Figure 1 This is a schematic diagram of the grafting sites of Tris on the PEI molecular chain in the polyetherimide film preparation method based on grafted trihydroxyaminomethane in this invention.

[0022] Figure 2 The image shows the DC breakdown field strength Weibull distribution of PEI at 25°C in the polyetherimide film preparation method based on grafted trihydroxyaminomethane according to the present invention.

[0023] Figure 3The image shows the DC breakdown field strength Weibull distribution of Tris-g-PEI at 25°C in the polyetherimide film preparation method based on grafted trihydroxyaminomethane according to the present invention.

[0024] Figure 4 This is a schematic diagram of the dielectric spectrum of the original PEI film at a temperature of 0-100℃, based on the method for preparing polyetherimide films using grafted trihydroxyaminomethane in this invention.

[0025] Figure 5 This is a schematic diagram of the dielectric spectrum of the Tris-g-PEI film at 0-100℃ based on the method for preparing polyetherimide films grafted with trihydroxyaminomethane in this invention.

[0026] Figure 6 This is a schematic diagram of the dielectric loss of the original PEI film at temperatures of 0-100℃ in the polyetherimide film preparation method based on grafted trihydroxyaminomethane in this invention.

[0027] Figure 7 This is a schematic diagram of the dielectric loss of Tris-g-PEI film at 0-100℃ in the preparation method of polyetherimide film based on grafted trihydroxyaminomethane according to the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. Figures 1 to 7 As shown, a method for preparing a polyetherimide film based on grafted trihydroxyaminomethane includes,

[0036] Step S100: Weigh a first mass of trihydroxyaminomethane and dissolve it in an aprotic polar solvent under continuous first stirring to obtain a trihydroxyaminomethane solution.

[0037] Step S200: Weigh a second mass of polyetherimide and dissolve it in the trihydroxyaminomethane solution under continuous second stirring to obtain a trihydroxyaminomethane-grafted polyetherimide solution.

[0038] Step S300: The trihydroxyaminomethane-grafted polyetherimide solution is degassed under vacuum to obtain a trihydroxyaminomethane-grafted polyetherimide casting solution.

[0039] In step S400, the trihydroxyaminomethane-grafted polyetherimide casting solution is coated onto a quartz glass plate using a doctor blade. After removing the solvent by stepwise heating and then vacuum drying, a trihydroxyaminomethane-grafted polyetherimide film is obtained.

[0040] In a preferred embodiment of the method for preparing polyetherimide films based on grafted trihydroxyaminomethane, in step S100, 0.05-0.1g of trihydroxyaminomethane is weighed using an electronic balance, and 10ml-20ml of polar aprotic solvent is measured using a graduated cylinder at room temperature. The first stirring conditions are: stirring with a mechanical stirrer at room temperature to 50°C, under a nitrogen atmosphere and at a speed of 100-500r / min for 0.5-4 hours.

[0041] In a preferred embodiment of the method for preparing polyetherimide films based on grafted trihydroxyaminomethane, the nonpolar organic solvent includes dimethylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone.

[0042] In a preferred embodiment of the method for preparing a polyetherimide film based on grafted trihydroxyaminomethane, in step S200, 1-2g of polyetherimide is weighed using an electronic balance, and the second stirring conditions are: a mechanical stirrer is used to stir for 2-6 hours at 60-80℃, under a nitrogen atmosphere and at a speed of 100r / min-1000r / min.

[0043] In a preferred embodiment of the method for preparing a polyetherimide film based on grafted trihydroxyaminomethane, in step S300, the trihydroxyaminomethane-grafted polyetherimide solution obtained from the reaction is degassed in a vacuum oven. The degassed temperature is controlled at 25-40°C and the pressure is below 10 Pa. The degassed process is continued for 1-2 hours to obtain a trihydroxyaminomethane-grafted polyetherimide casting solution.

[0044] In a preferred embodiment of the method for preparing a polyetherimide film based on grafted trihydroxyaminomethane, the doctor blade speed is 10-20 mm / s; the step temperature rise is 60℃ for 20 minutes, 90℃ for 0.5 hours, and 120℃ for 1 hour. After the solvent is dried, the glass plate is transferred to a vacuum oven for further drying at 150℃-200℃ for 12-24 hours, finally obtaining a trihydroxyaminomethane-grafted polyetherimide film.

[0045] In a preferred embodiment of the method for preparing a polyetherimide film based on grafted trihydroxyaminomethane, the breakdown field strength of the trihydroxyaminomethane-grafted polyetherimide film is at least 602.5 MV / m, and the dielectric constant is 3.3-3.4.

[0046] In one embodiment, the ratio of the first mass to the second mass is 1:2.

[0047] In one embodiment, the first mass is 0.75g and the second mass is 1.5g.

[0048] In one embodiment, the method includes the following steps:

[0049] S100. Weigh a certain mass fraction of trihydroxyaminomethane (Tris) and dissolve it in an aprotic polar solvent under continuous vigorous stirring, heating and nitrogen purging to obtain a trihydroxyaminomethane solution.

[0050] S200. Weigh a certain mass fraction of polyetherimide (PEI) and dissolve it in a trihydroxyaminomethane solution under continuous vigorous stirring, heating and nitrogen purging to obtain a trihydroxyaminomethane-grafted polyetherimide (Tris-g-PEI) solution.

[0051] S300. The trihydroxyaminomethane-grafted polyetherimide solution obtained from the reaction is degassed under vacuum to obtain Tris-g-PEI casting solution.

[0052] S400: The Tris-g-PEI casting solution is coated onto a clean quartz glass plate with a doctor blade, the solvent is removed by step heating, and then the film is dried under vacuum to obtain a Tris-g-PEI film.

[0053] Step S100 includes:

[0054] Weigh 0.05-0.1 g of trihydroxyaminomethane using an electronic balance. Measure 10-20 ml of a polar aprotic solvent solution of dimethylformamide using a graduated cylinder at room temperature. Mix the two materials thoroughly in a flask and stir mechanically at room temperature to 50°C under a nitrogen atmosphere and a speed of 100-500 rpm for 0.5-4 hours to obtain a trihydroxyaminomethane solution. Polar aprotic solvents include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

[0055] Step S200 includes:

[0056] Weigh 1-2g of polyetherimide using an electronic balance, quickly pour it into a trihydroxyaminomethane solution, and stir with a mechanical stirrer at 60-80℃, nitrogen atmosphere, and 100r / min-1000r / min for 2-6 hours. After sufficient reaction, a trihydroxyaminomethane-grafted polyetherimide (Tris-g-PEI) solution is obtained.

[0057] In one embodiment, the trihydroxyaminomethane-grafted polyetherimide solution obtained from the reaction is degassed under vacuum in a vacuum oven at a temperature controlled at 25-40°C and a pressure below 10 Pa for 1-2 hours to obtain a Tris-g-PEI casting solution. A clean quartz glass plate is placed in an oven or on a heating table, and the Tris-g-PEI casting solution is coated onto the quartz glass plate using a doctor blade at a speed of 10-20 mm / s. The step temperature program is as follows: 60°C for 20 minutes, 90°C for 0.5 hours, and 120°C for 1 hour. After the solvent has dried, the glass plate is transferred to a vacuum oven for further drying at 150°C-200°C for 12-24 hours to finally obtain a Tris-g-PEI film.

[0058] In one embodiment, Figure 1 These are the grafting sites of Tris on the PEI molecular chain. Primarily, the amino groups inherent in Tris cause the imide ring on the polyether imide molecular chain to open, thereby grafting hydroxyl groups, such as... Figure 2 and Figure 3 The image shows the Weibull distribution of the DC breakdown field strength of PEI and Tris-g-PEI at 25℃. The experimental results indicate that grafting trihydroxyaminomethane effectively improves the breakdown field strength of polyetherimide, suggesting that the introduced hydrogen bonds help enhance the intermolecular chain interactions and reduce film defects and free volume. Figure 4 and Figure 5The figures show the dielectric spectra of PEI and Tris-g-PEI from 0℃ to 100℃. It can be seen that the dielectric constants of both PEI and Tris-g-PEI increase slightly with increasing temperature, which may be related to the enhanced dipole motion per unit volume of the polymer at high temperatures. The introduction of the polar hydroxyl group after Tris grafting increases the number of dipoles per unit volume in Tris-g-PEI, thus significantly increasing the dielectric constant compared to the original PEI. Figure 6 and Figure 7 The dielectric losses of PEI and Tris-g-PEI from 0℃ to 100℃ are shown. It can be seen that the dielectric losses of PEI and Tris-g-PEI remain on the same order of magnitude. Therefore, the introduction of the polar hydroxyl group after grafting Tris does not significantly increase the dielectric loss. The energy storage density of the dielectric is proportional to the square of the breakdown field strength and the dielectric constant. Without a significant increase in dielectric loss, Tris-g-PEI significantly improves the breakdown field strength and dielectric constant of polyetherimide, thus effectively improving the energy storage density.

[0059] Finally, it should be noted that the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0060] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a polyetherimide film based on grafted tris-hydroxy aminomethane, characterized in that, It comprises the following steps: Step S100, weigh a first mass of trihydroxy aminomethane, dissolve in an aprotic polar solvent under the condition of continuous first stirring to obtain a trihydroxy aminomethane solution; Step S200, weigh a second mass of polyetherimide, dissolve in the trihydroxy aminomethane solution under the condition of continuous second stirring to obtain a trihydroxy aminomethane grafted polyetherimide solution; Step S300, vacuum degassing of the trihydroxy aminomethane grafted polyetherimide solution to obtain a trihydroxy aminomethane grafted polyetherimide casting solution; Step S400, the trihydroxy aminomethane grafted polyetherimide casting solution is coated on a quartz glass plate with a doctor blade, and after removing the solvent by stepwise heating and vacuum drying, a trihydroxy aminomethane grafted polyetherimide film is obtained.

2. The method for preparing a polyetherimide film based on grafted trihydroxyaminomethane according to claim 1, characterized in that, In step S100, 0.05-0.1g of trihydroxy aminomethane is weighed with an electronic balance, and 10-20ml of a polar aprotic solvent is measured at room temperature with a graduated cylinder. The first stirring condition is: stirring at room temperature to 50℃, in a nitrogen atmosphere and at a speed of 100-500 r / min for 0.5-4 hours with a mechanical stirring device.

3. The method of claim 2, wherein the polyetherimide film is based on grafted trihydroxyaminomethane. The aprotic polar organic solvent includes dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone.

4. The method of claim 1, wherein the polyetherimide film is based on grafted trisamino-methylolane. 5 In step S200, 1-2g of polyetherimide is weighed with an electronic balance. The second stirring condition is: stirring at 60-80℃, in a nitrogen atmosphere and at a speed of 100-1000 r / min for 2-6 hours with a mechanical stirring device.

5. The method of claim 1, wherein the polyetherimide film is based on grafted trisamino-methylolane. 5 In step S300, the trihydroxy aminomethane grafted polyetherimide solution obtained by reaction is vacuum degassed with a vacuum oven. The degassing temperature is controlled at 25-40℃, the gas pressure is below 10 Pa, and the degassing is continued for 1-2h to obtain a trihydroxy aminomethane grafted polyetherimide casting solution.

6. The method of claim 1, wherein the polyetherimide film is based on grafted trisamino-methylolane. The doctor blade speed is 10-20mm / s; the stepwise heating is 60℃ for 20 minutes, 90℃ for 0.5 hours and 120℃ for 1 hour. After the solvent is dried, the glass plate is transferred into a vacuum oven for further drying at a temperature of 150-200℃ for 12-24 hours, and finally a trihydroxy aminomethane grafted polyetherimide film is obtained.

7. The method of claim 1, wherein the polyetherimide film is based on grafted trisamino-methylolane.

8. The method of claim 1, wherein the polyetherimide film is based on grafted trisamino-methylolane. The breakdown field strength of the trihydroxy aminomethane grafted polyetherimide film is at least 602.5MV / m, and the dielectric constant is 3.3-3.4.

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