Polyimide derivative with modified side group for capacitor as well as preparation method and application of polyimide derivative

Abstract

The invention discloses a side group modified polyimide derivative for a capacitor as well as a preparation method and application of the side group modified polyimide derivative. The side group modified polyimide derivative for the capacitor is obtained by polymerizing a diamine monomer and a dianhydride monomer; the side groups of the diamine monomer and the dianhydride monomer comprise at least one of-F,-SO3H,-CF3,-NO2,-Cl and-CN, (1) the diamine monomer is selected from at least one of A2-A4 and A6-A9, and the dianhydride monomer is selected from at least one of B1, B2 and B4; or (2) the diamine monomer is selected from at least one of A1-A10, and the dianhydride monomer is selected from B3. The side group modified polyimide derivative for the capacitor prepared by the invention has excellent high-temperature capacitance performance.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature polymer dielectric materials and capacitors, and in particular to a side-group-modified polyimide derivative for capacitors, and a preparation method and application thereof. Background Art

[0002] Dielectric capacitors are vital energy storage components in modern electronic devices and power systems due to their ultrafast charging and discharging characteristics. Polymer dielectric materials have become the material of choice for high-voltage dielectric capacitors due to their high-voltage resistance and easy processing. However, these organic materials face huge challenges in emerging applications in mainstream technologies such as renewable energy, electrified transportation, and advanced propulsion systems. In currently available polymer dielectrics, high electric field capacitance performance and thermal stability are often mutually exclusive, which may be due to the heat resistance obtained by these polymers through highly conjugated structures. However, the conductivity loss of highly conjugated polymer dielectrics increases sharply under high temperature and strong electric field conditions, resulting in a significant decrease in energy storage density, which cannot meet the application requirements of thin film capacitors. Therefore, how to effectively suppress the conductivity loss at high temperature has become a technical problem that needs to be solved urgently.

[0003] In the past, the polyimide side group modification scheme, such as that disclosed in patent document CN115160154A, had a relatively complicated preparation process and did not disclose the specific effect of the addition of the side groups on the properties of the polyimide.

[0004] In summary, the development of a new polyimide material that utilizes side group modification to improve high-temperature capacitance performance is of great significance for the development of high-performance high-temperature dielectric materials. Summary of the invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a polyimide derivative modified with side groups for capacitors and a preparation method and application thereof.

[0006] The technical solution adopted by the present invention is: A side-group modified polyimide derivative for capacitors, obtained by polymerization of a diamine monomer and a dianhydride monomer; (1) the diamine monomer is selected from at least one of A2-A4 and A6-A9, and the dianhydride monomer is selected from at least one of B1, B2 and B4; or (2) the diamine monomer is selected from at least one of A1 to A10, and the dianhydride monomer is selected from B3; .

[0007] The side groups of the diamine monomer and the dianhydride monomer include at least one of -F, -SO3H, -CF3, -NO2, -Cl, and -CN.

[0008] Preferably, the structural formula of the polyimide derivative is as follows: .

[0009] The method for preparing the above-mentioned capacitor-use side-group-modified polyimide derivative comprises the following steps: (1) Add the diamine monomer to the solvent, then add the dianhydride monomer, and stir to react; (2) The solution obtained in step (1) is dried and subjected to high temperature annealing to obtain a polyimide derivative modified with a side group for capacitors.

[0010] Preferably, the stirring reaction in step (1) is carried out at a temperature of 80-90° C. and for a time of 12-16 h.

[0011] Preferably, the solvent in step (1) is N-methylpyrrolidone (NMP).

[0012] Preferably, the molar ratio of the diamine monomer to the dianhydride monomer in step (1) is 1:(0.5-1.5).

[0013] Preferably, in step (1), the ratio of the total mass of the diamine monomer and the dianhydride monomer to the volume of the solvent is 300-400 mg:10 ml.

[0014] Preferably, the drying temperature in step (2) is 80-90°C and the drying time is 12-16 h; Preferably, the solution is cast on a glass plate before drying in step (2).

[0015] Preferably, the high temperature annealing treatment in step (2) is carried out at 100-110°C, 150-160°C, 200-210°C, 250-260°C for 1-2 hours each.

[0016] The above-mentioned capacitor side-group modified polyimide derivative is used as a high-temperature polymer dielectric material or in the preparation of a high-temperature capacitor.

[0017] Compared with the prior art, the advantages and beneficial effects of the present invention include: (1) The present invention uses machine learning technology to successfully and rapidly construct a "material genome", screen out various monomers suitable for synthesis and large-scale preparation, and promote the design and completion of experiments.

[0018] (2) The present invention discloses the influence of different side groups on the band gap width and glass transition temperature of polyimide-derived polymers based on different side group modifications.

[0019] (3) The polyimide-derived polymer prepared by the present invention has excellent high-temperature capacitance performance, and the capacitance performance is improved above 200°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1a The breakdown strength of different polyimide-derived polymers of Examples 1-3 and Comparative Example 1 at 200°C.

[0021] Figure 1b The breakdown strength of different polyimide-derived polymers of Examples 5-8 and Comparative Example 3 at 200°C.

[0022] Figure 2 The dielectric properties of different polyimide-derived polymers of Examples 1-3 and Comparative Example 1 at 200°C.

[0023] Figure 3 The relationship between the leakage current density and the electric field of different polyimide-derived polymers of Examples 1-3 and Comparative Example 1 at 200°C.

[0024] Figure 4 The high temperature capacitance performance of different polyimide-derived polymers of Examples 1-3 and Comparative Example 1 at 200°C.

[0025] Figure 5 The high temperature capacitance performance of different polyimide-derived polymers of Examples 5-8 and Comparative Example 3 at 200°C.

[0026] Figure 6 The high temperature capacitance performance of different polyimide-derived polymers of Example 4 and Comparative Example 2 at 250°C. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further explained below in conjunction with specific embodiments and drawings.

[0028] Based on the combination strategy, the present invention screens a variety of diamine and dianhydride monomers through machine learning, and predicts the effects of different monomer combinations on the polymer band gap (E g ) and glass transition temperature (T g ) and confirmed its actual performance through experiments, and finally screened out monomers carrying side groups; by analyzing the experimental results and combining them with computational simulations, the influence of each structural unit on the electrical and thermal properties of the resulting polymer was quantitatively determined, and the key factors related to the capacitance performance at high temperatures were revealed. At the same time, polyimide-derived polymers with excellent high-temperature capacitance performance were obtained by side group modification, which provides a promising direction for high-temperature polymer dielectrics.

[0029] The structural formulas of the diamine monomers (A1-A10) and dianhydride monomers (B1-B4) involved in the following examples and comparative examples are as follows: .

[0030] The structural formulas of polyimide (PI), polyimide-fluorine (PI-F), polyimide-sulfonyl (PI-SO3H), polyimide-trifluoromethyl (PI-CF3), PI-oxo-iso, PI-CF3-iso, PEI, PEI-NO2, PEI-Cl, PEI-CF3, and PEI-CN involved in the following examples and comparative examples are as follows: .

[0031] Example 1 A polyimide-derived polymer (PI-F) with improved high-temperature capacitance performance based on side group modification, and a preparation method thereof is as follows: (1) Add 0.6 mmol of diamine monomer (A2) to 10 ml of N-methylpyrrolidone (NMP) solution. Then, add an equal molar amount of dianhydride monomer (B1) to the mixed solution and stir at 80°C for 12 h to ensure that the diamine and dianhydride monomers react to form poly(amic acid).

[0032] (2) The reacted solution was cast onto a pre-cleaned glass plate and dried at 80°C for 12 h. In order to make the polyamino acid undergo imidization reaction, the sample needs to be subjected to additional high-temperature treatment. The polymer was heat treated in an oven using a gradient heating method, and the gradient heat treatment process was 100, 150, 200, and 250°C for 1 hour each.

[0033] (3) After cooling naturally to room temperature, the membrane was peeled off in deionized water and dried in a vacuum oven at 100 °C to remove residual moisture.

[0034] Example 2 A polyimide-derived polymer (PI-SO3H) with improved high-temperature capacitance performance based on side group modification, and a preparation method thereof is as follows: (1) Add 0.4 mmol of diamine monomer (A4) to 10 ml of N-methylpyrrolidone (NMP) solution. Then, add an equal molar amount of dianhydride monomer (B1) to the mixed solution and stir at 80°C for 12 h to ensure that the diamine and dianhydride monomers react to form poly(amic acid).

[0035] (2) The reacted solution was cast onto a pre-cleaned glass plate and dried at 80°C for 12 h. In order to make the polyamino acid undergo imidization reaction, the sample needs to be subjected to additional high-temperature treatment. The polymer was heat treated in an oven using a gradient heating method, and the gradient heat treatment process was 100, 150, 200, and 250°C for 1 hour each.

[0036] (3) After cooling naturally to room temperature, the membrane was peeled off in deionized water and dried in a vacuum oven at 100 °C to remove residual moisture.

[0037] Example 3 A polyimide-derived polymer (PI-CF3) with improved high-temperature capacitance performance based on side group modification, and a preparation method thereof is as follows: (1) Add 0.5 mmol of diamine monomer (A3) to 10 ml of N-methylpyrrolidone (NMP) solution. Then, add an equal molar amount of dianhydride monomer (B1) to the mixed solution and stir at 80°C for 12 h to ensure that the diamine and dianhydride monomers react to form poly(amic acid).

[0038] (2) The reacted solution was cast onto a pre-cleaned glass plate and dried at 80°C for 12 h. In order to make the polyamino acid undergo imidization reaction, the sample needs to be subjected to additional high-temperature treatment. The polymer was heat treated in an oven using a gradient heating method, and the gradient heat treatment process was 100, 150, 200, and 250°C for 1 hour each.

[0039] (3) After cooling naturally to room temperature, the membrane was peeled off in deionized water and dried in a vacuum oven at 100 °C to remove residual moisture.

[0040] Example 4 A polyimide-derived polymer (PI-CF3-iso) with improved high-temperature capacitance performance based on side group modification, and a preparation method thereof is as follows: (1) 0.4 mmol of diamine monomer (A5) was added to 10 ml of N-methylpyrrolidone (NMP) solution. Then, an equal molar amount of dianhydride monomer (B3) was added to the mixed solution and stirred at 80 °C for 12 h to ensure that the diamine and dianhydride monomers reacted to form poly(amic acid).

[0041] (2) The reacted solution was cast onto a pre-cleaned glass plate and dried at 80°C for 12 h. In order to make the polyamino acid undergo imidization reaction, the sample needs to be subjected to additional high-temperature treatment. The polymer was heat treated in an oven using a gradient heating method, and the gradient heat treatment process was 100, 150, 200, and 250°C for 1 hour each.

[0042] (3) After cooling naturally to room temperature, the membrane was peeled off in deionized water and dried in a vacuum oven at 100 °C to remove residual moisture.

[0043] Example 5 A polyimide-derived polymer (PEI-NO2) with improved high-temperature capacitance performance based on side group modification, and a preparation method thereof is as follows: (1) 0.4 mmol of diamine monomer (A6) was added to 10 ml of N-methylpyrrolidone (NMP) solution. Then, an equal molar amount of dianhydride monomer (B4) was added to the mixed solution and stirred at 80 °C for 12 h to ensure that the diamine and dianhydride monomers reacted to form poly(amic acid).

[0044] (2) The reacted solution was cast onto a pre-cleaned glass plate and dried at 80°C for 12 h. In order to make the polyamino acid undergo imidization reaction, the sample needs to be subjected to additional high-temperature treatment. The polymer was heat treated in an oven using a gradient heating method, and the gradient heat treatment process was 100, 150, 200, and 250°C for 1 hour each.

[0045] (3) After cooling naturally to room temperature, the membrane was peeled off in deionized water and dried in a vacuum oven at 100 °C to remove residual moisture.

[0046] Example 6 A polyimide-derived polymer (PEI-Cl) with improved high-temperature capacitance performance based on side group modification, and a preparation method thereof is as follows: (1) Add 0.5 mmol of diamine monomer (A7) to 10 ml of N-methylpyrrolidone (NMP) solution. Then, add an equal molar amount of dianhydride monomer (B4) to the mixed solution and stir at 80°C for 12 h to ensure that the diamine and dianhydride monomers react to form poly(amic acid).

[0047] (2) The reacted solution was cast onto a pre-cleaned glass plate and dried at 80°C for 12 h. In order to make the polyamino acid undergo imidization reaction, the sample needs to be subjected to additional high-temperature treatment. The polymer was heat treated in an oven using a gradient heating method, and the gradient heat treatment process was 100, 150, 200, and 250°C for 1 hour each.

[0048] (3) After cooling naturally to room temperature, the membrane was peeled off in deionized water and dried in a vacuum oven at 100 °C to remove residual moisture.

[0049] Example 7 A polyimide-derived polymer (PEI-CF3) with improved high-temperature capacitance performance based on side group modification, and a preparation method thereof is as follows: (1) 0.4 mmol of diamine monomer (A8) was added to 10 ml of N-methylpyrrolidone (NMP) solution. Then, an equal molar amount of dianhydride monomer (B4) was added to the mixed solution and stirred at 80 °C for 12 h to ensure that the diamine and dianhydride monomers reacted to form poly(amic acid).

[0050] (2) The reacted solution was cast onto a pre-cleaned glass plate and dried at 80°C for 12 h. In order to make the polyamino acid undergo imidization reaction, the sample needs to be subjected to additional high-temperature treatment. The polymer was heat treated in an oven using a gradient heating method, and the gradient heat treatment process was 100, 150, 200, and 250°C for 1 hour each.

[0051] (3) After cooling naturally to room temperature, the membrane was peeled off in deionized water and dried in a vacuum oven at 100 °C to remove residual moisture.

[0052] Example 8 A polyimide-derived polymer (PEI-CN) with improved high-temperature capacitance performance based on side group modification, and a preparation method thereof is as follows: (1) Add 0.5 mmol of diamine monomer (A9) to 10 ml of N-methylpyrrolidone (NMP) solution. Then, add an equal molar amount of dianhydride monomer (B4) to the mixed solution and stir at 80°C for 12 h to ensure that the diamine and dianhydride monomers react to form poly(amic acid).

[0053] (2) The reacted solution was cast onto a pre-cleaned glass plate and dried at 80°C for 12 h. In order to make the polyamino acid undergo imidization reaction, the sample needs to be subjected to additional high-temperature treatment. The polymer was heat treated in an oven using a gradient heating method, and the gradient heat treatment process was 100, 150, 200, and 250°C for 1 hour each.

[0054] (3) After cooling naturally to room temperature, the membrane was peeled off in deionized water and dried in a vacuum oven at 100 °C to remove residual moisture.

[0055] Comparative Example 1 A pure polyimide polymer (PI), the preparation method of which is: (1) Add 0.8 mmol of diamine monomer (A1) to 10 ml of N-methylpyrrolidone (NMP) solution. Then, add an equal molar amount of dianhydride monomer (B1) to the mixed solution and stir at 80°C for 12 h to ensure that the diamine and dianhydride monomers react to form poly(amic acid).

[0056] (2) The reacted solution was cast onto a pre-cleaned glass plate and dried at 80°C for 12 h. In order to make the polyamino acid undergo imidization reaction, the sample needs to be subjected to additional high-temperature treatment. The polymer was heat treated in an oven using a gradient heating method, and the gradient heat treatment process was 100, 150, 200, and 250°C for 1 hour each.

[0057] (3) After cooling naturally to room temperature, the membrane was peeled off in deionized water and dried in a vacuum oven at 100 °C to remove residual moisture.

[0058] Comparative Example 2 A polyimide polymer (PI-oxo-iso) without side group modification is prepared by: (1) 0.4 mmol of diamine monomer (A5) was added to 10 ml of N-methylpyrrolidone (NMP) solution. Then, an equal molar amount of dianhydride monomer (B2) was added to the mixed solution and stirred at 80 °C for 12 h to ensure that the diamine and dianhydride monomers reacted to form poly(amic acid).

[0059] (2) The reacted solution was cast onto a pre-cleaned glass plate and dried at 80°C for 12 h. In order to make the polyamino acid undergo imidization reaction, the sample needs to be subjected to additional high-temperature treatment. The polymer was heat treated in an oven using a gradient heating method, and the gradient heat treatment process was 100, 150, 200, and 250°C for 1 hour each.

[0060] (3) After cooling naturally to room temperature, the membrane was peeled off in deionized water and dried in a vacuum oven at 100 °C to remove residual moisture.

[0061] Comparative Example 3 A polyimide polymer (PEI) without side group modification, the preparation method of which is as follows: (1) 0.5 mmol of diamine monomer (A10) was added to 10 ml of N-methylpyrrolidone (NMP) solution. Then, an equal molar amount of dianhydride monomer (B4) was added to the mixed solution and stirred at 80 °C for 12 h to ensure that the diamine and dianhydride monomers reacted to form poly(amic acid).

[0062] (2) The reacted solution was cast onto a pre-cleaned glass plate and dried at 80°C for 12 h. In order to make the polyamino acid undergo imidization reaction, the sample needs to be subjected to additional high-temperature treatment. The polymer was heat treated in an oven using a gradient heating method, and the gradient heat treatment process was 100, 150, 200, and 250°C for 1 hour each.

[0063] (3) After cooling naturally to room temperature, the membrane was peeled off in deionized water and dried in a vacuum oven at 100 °C to remove residual moisture.

[0064] Performance Testing 1. E of each polymer of Examples 1-3 and Comparative Example 1 g With T g As shown in Table 1. By comparison, it is found that the insertion of -F in the polymer PI-F of Example 1 makes E g The T gThe temperature of E g The T g The temperature dropped by 10.2℃. The introduction of -CF3 in the polymer PI-CF3 in Example 3 made E g The T g Dropped by 18℃.

[0065] The E of each polymer of Examples 5-8 and Comparative Example 3 g With T g As shown in Table 1. By comparison, it was found that the introduction of NO2 side groups on m-phenylenediamine resulted in a decrease in the polymer band gap, while the introduction of Cl, CF3 and CN side groups increased the polymer band gap width and glass transition temperature to varying degrees.

[0066] Table 1 E of each polymer g With T g

[0067] 2. The breakdown strength of the polyimide-derived polymers of Examples 1-3 and Comparative Example 1 at 200°C is as follows: Figure 1a As shown, it can be found that under 200°C environment, the introduction of side groups can improve the breakdown strength of polyimide materials. Among them, the polyimide-derived polymer with side groups grafted with sulfonyl groups has the best high-temperature breakdown strength.

[0068] The breakdown strength of the polyimide-derived polymers of Examples 5-8 and Comparative Example 3 at 200°C is as follows: Figure 1b As shown, it can be found that at 200°C, the introduction of NO2 side groups will reduce the breakdown strength of the polyetherimide material, and the introduction of Cl, CF3 and CN side groups will enhance the breakdown strength of the polyetherimide material to varying degrees.

[0069] 3. The dielectric properties of the polyimide-derived polymers of Examples 1-3 and Comparative Example 1 at 200°C are as follows: Figure 2 As shown in the figure, it can be found that at 200°C, the dielectric constants of PI-F and PI-CF3 polyimide-derived polymers did not change much, while the dielectric constant of PI-SO3H polyimide-derived polymer increased. At the same time, due to the high polarization and high dipole moment properties of the sulfonyl group, the dielectric loss of PI-SO3H polyimide-derived polymer increased slightly.

[0070] 4. The relationship between the leakage current density and the electric field at 200°C of Examples 1-3 and Comparative Example 1 is as follows: Figure 3 As shown. Figure 3It can be seen that in the polyimide-derived polymer containing rigid dianhydride, the leakage current density measured at 200°C changes from Schottky injection to Frank emission as the electric field increases. With the introduction of side groups, the leakage current of the polyimide-derived polymer at 200°C is effectively suppressed.

[0071] 5. The high temperature capacitance performance of Examples 1-3 and Comparative Example 1 at 200°C is as follows: Figure 4 As shown by Figure 4 It can be seen that with the increase of Eg, the Ue and η The results show that the Schottky injection barrier and the Frank emission activation energy are dependent on Eg. At the same time, with the introduction of side groups, the free volume of the molecular chain is increased to varying degrees, which can effectively enhance the high temperature capacitance performance of polyimide-derived polymers.

[0072] 6. The high temperature capacitance performance of Examples 5-8 and Comparative Example 3 at 200°C is as follows: Figure 5 As shown by Figure 5 It can be seen that with the introduction of CN side groups, the high-temperature capacitance performance of polyetherimide-derived polymers is significantly enhanced.

[0073] 7. By comparing Examples 1-3 with Comparative Example 1, it is found that the introduction of -CF3 on the polyimide derivative polymer can best improve the high temperature capacitance performance. Subsequently, the high temperature capacitance performance of Example 4 and Comparative Example 2 at 250°C is tested. Figure 6 As shown, it was found that the introduction of -CF3 into the dianhydride monomer can greatly improve the high-temperature capacitance performance of the polyimide-derived polymer at 250°C, with unprecedented energy storage performance.

Claims

1. A polyimide derivative modified with a side group for capacitors, characterized in that: Obtained by polymerization of diamine monomers and dianhydride monomers; (1) the diamine monomer is selected from at least one of A2-A4 and A6-A9, and the dianhydride monomer is selected from at least one of B1, B2 and B4; or (2) the diamine monomer is selected from at least one of A1 to A10, and the dianhydride monomer is selected from B3; 。 2. The side-group-modified polyimide derivative for capacitors according to claim 1, characterized in that: The structural formula of the polyimide derivative is as follows: .

3. The method for preparing the side-group modified polyimide derivative for capacitors according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) Add the diamine monomer to the solvent, then add the dianhydride monomer, and stir to react; (2) The solution obtained in step (1) is dried and subjected to high temperature annealing to obtain a polyimide derivative modified with a side group for capacitors.

4. The preparation method according to claim 3, characterized in that: The stirring reaction in step (1) is carried out at a temperature of 80-90°C and for a time of 12-16 h.

5. The preparation method according to claim 3, characterized in that: The solvent in step (1) is N-methylpyrrolidone.

6. The preparation method according to claim 3, characterized in that: The molar ratio of the diamine monomer to the dianhydride monomer in step (1) is 1:(0.5-1.5).

7. The preparation method according to claim 3, characterized in that: In step (1), the ratio of the total mass of the diamine monomer and the dianhydride monomer to the volume of the solvent is 300-400 mg:10 ml.

8. The preparation method according to claim 3, characterized in that: The drying temperature in step (2) is 80-90°C and the drying time is 12-16 hours; The solution is cast on a glass plate before drying in step (2).

9. The preparation method according to claim 3, characterized in that: The high temperature annealing treatment in step (2) is carried out at 100-110°C, 150-160°C, 200-210°C, and 250-260°C for 1-2 hours respectively.

10. Use of the capacitor-use side-group-modified polyimide derivative according to any one of claims 1 to 2 as a high-temperature polymer dielectric material or in the preparation of a high-temperature capacitor.

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