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CN-122011456-A - Polyimide dielectric film and preparation method and application thereof

CN122011456ACN 122011456 ACN122011456 ACN 122011456ACN-122011456-A

Abstract

The invention relates to the field of dielectric films, in particular to a polyimide dielectric film, a preparation method and application thereof. The preparation method of the polyimide dielectric film comprises the steps of mixing 1, 3-m-phenylenediamine, tC diamine monomers, anhydride monomers and an organic solvent in an inert atmosphere to obtain a mixed solution, carrying out polycondensation reaction on the mixed solution in the inert atmosphere to obtain a precursor solution, and coating the precursor solution on a substrate to carry out imidization to obtain the polyimide dielectric film. According to the invention, semi-aromatic PI constructed by commonly used MPD is taken as a matrix, tC diamine monomers with high rigidity and configuration disturbance characteristics are copolymerized and introduced into a main chain in a controllable proportion, so that the cooperative regulation and control of the thermal motion of chain segments and an aggregation state structure are realized, and better high-temperature energy storage stability and breakdown reliability are obtained.

Inventors

  • ZHANG DOU
  • HU DENG
  • LUO XING

Assignees

  • 中南大学

Dates

Publication Date
20260512
Application Date
20260331

Claims (10)

  1. 1. A preparation method of a polyimide dielectric film is characterized by comprising the following steps: Mixing 1, 3-m-phenylenediamine, tC diamine monomer, anhydride monomer and organic solvent under inert atmosphere to obtain mixed solution; performing polycondensation reaction on the mixed solution in an inert atmosphere to obtain a precursor solution; Coating the precursor solution on a substrate for imidization to obtain the polyimide dielectric film.
  2. 2. The method for producing a polyimide-based dielectric film according to claim 1, wherein the molar ratio of the 1, 3-m-phenylenediamine to the tC-based diamine monomer is (90 to 99): 1 to 10.
  3. 3. The method for producing a polyimide-based dielectric film according to claim 1, wherein the ratio of the molar amount of the acid anhydride monomer to the total molar amount of the 1, 3-m-phenylenediamine and tC-based diamine monomer is 1:1 to 1:1.05.
  4. 4. The method for producing a polyimide-based dielectric film according to claim 1, wherein the solute content in the mixed solution is 10wt% to 20wt%.
  5. 5. The method for producing a polyimide-based dielectric film according to claim 1, wherein the tC-based diamine monomer includes at least one of 4,4' - (propane-2, 2-diyl) diphenylamine, 1-bis (4-aminophenyl) cyclohexane, 2-bis (4-aminophenyl) hexafluoropropane, and 4,4' -diamino-3, 3' -dimethyl diphenyl methane.
  6. 6. The method for producing a polyimide-based dielectric film according to claim 1, wherein the acid anhydride monomer comprises dicyclohexyl-3, 4,3',4' -tetracarboxylic dianhydride, 1,2,4, 5-cyclohexane tetracarboxylic dianhydride, or 4,4' - (hexafluoroisopropylene) diphthalic anhydride.
  7. 7. The method for producing a polyimide-based dielectric film according to claim 1, wherein the temperature of the polycondensation reaction is 15 to 25 ℃, and the time of the polycondensation reaction is 12 to 24 hours; the ambient temperature of the coating is 50-80 ℃; The method further comprises drying after the coating is finished.
  8. 8. The method for producing a polyimide-based dielectric film according to claim 1, wherein the imidization process: firstly, reacting for 2-3 hours at 160-210 ℃ in an oxygen atmosphere, and then reacting for 2-3 hours at 260-300 ℃ in a vacuum condition.
  9. 9. A polyimide-based dielectric film produced by the process for producing a polyimide-based dielectric film according to any one of claims 1 to 8; the thickness of the polyimide dielectric film is 9-11 mu m.
  10. 10. Use of the polyimide-based dielectric film of claim 9 in a dielectric capacitor.

Description

Polyimide dielectric film and preparation method and application thereof Technical Field The invention relates to the field of dielectric films, in particular to a polyimide dielectric film, a preparation method and application thereof. Background The high-temperature dielectric film capacitor is a key basic element in the fields of aerospace electric propulsion, deep well exploration, pulse power systems and the like, the service environment of the high-temperature dielectric film capacitor requires the device to stably work for a long time under the conditions of high electric field and high temperature, and the high-energy density, high efficiency, high stability and wide-temperature-range comprehensive performance requirements are provided for the core dielectric material. At present, the existing dielectric materials are difficult to meet the extreme service requirements, and obvious performance short plates exist. The general polymer medium represented by polypropylene has the advantages of low loss and high breakdown strength, but has lower upper heat resistance limit and insufficient temperature stability, natural bottleneck exists in high-temperature power capacitor application, long-term stable operation under high-temperature working conditions cannot be adapted, while inorganic ceramic medium has the characteristics of high temperature resistance and higher dielectric constant, but is limited by the problems of high brittleness, difficult film forming, sensitive interface defects and the like, and dielectric nonlinearity phenomenon is easy to occur under an alternating electric field, so that the reliability is difficult to guarantee. Therefore, development of polymer dielectric materials capable of combining flexible processing characteristics and high-temperature resistance and strong electric field resistance has become an important research direction in the field of high-temperature energy storage devices. Among various high temperature polymer dielectrics, polyimide (PI) films are considered as one of the most potential materials for application due to their excellent thermal stability, mechanical strength and chemical resistance. However, the energy storage application of polyimide under a high-temperature strong electric field still faces multiple performance contradictory constraints which are difficult to reconcile, specifically, on one hand, the dielectric constant of polyimide is usually required to be improved, strong polar groups are usually required to be introduced, or the polarization capability of chain segment charges is enhanced, but the mode is often accompanied by the problems of increasing dielectric loss and enhancing conductivity contribution, so that the charge and discharge efficiency of the material is reduced, and Joule heat is aggravated, and the long-term stability of the device is affected, on the other hand, the breakdown strength of the material is required to be reduced, the charge injection and transmission are inhibited, and the distortion of a local electric field is reduced, but a high-plane rigidity or high-conjugated structure induces stronger intermolecular interaction and orderly accumulation while the thermal stability and mechanical modulus of the material are improved, so that a 'fast channel' of charge migration is formed, even an electron transfer complex is formed in a compounding manner, and the breakdown strength of the material is reduced. In addition, the performance degradation is further aggravated by the high temperature environment, namely the high temperature can obviously enhance the motion capability and free volume evolution of polyimide molecular chain segments, promote the accumulation of space charges and the rise of conduction loss, and finally lead the energy density and the charge-discharge efficiency of the material to decay rapidly along with the rise of temperature. Aiming at the performance contradiction caused by coupling of chain segment structure, aggregation state and charge excitation behavior, the existing modification thought mainly comprises composite enhancement, intrinsic structure design, copolymerization regulation and control and the like. In contrast, the copolymerization regulation and control route is hopeful to simultaneously regulate the interaction between the rigidity of chain segments and chains from the level of a molecular main chain, so as to synergistically improve the thermal stability, an aggregation state structure and the charge migration behavior of the material and better meet the performance requirements of a high-temperature energy storage film, but the conventional copolymerization regulation and control scheme still cannot effectively solve the problem of compromise between improving the glass transition temperature (Tg) of polyimide, maintaining the toughness of the film and inhibiting ordered accumulation among chains, and cannot meet the extreme service requirements of a high-temperature d