Application of 3, 4, 5-trifluorobromobenzene in electric storage polymer coating

Abstract

The invention discloses an application of 3, 4, 5-trifluorobromobenzene in an electric storage polymer coating, and the electric storage polymer coating is prepared from hyperbranched polyimide based on 3, 4, 5-trifluorophenyl through a spin coating method. The coating is high in solubility, good in processability and low in water absorption; the hyperbranched polyimide is formed by polymerizing a diamine compound containing 3, 4, 5-trifluorophenyl and polybasic acid anhydride, the hyperbranched polyimide has a triphenylamine structure and trifluorophenyl, tight packing of molecular chains can be improved under the combined action of torsional motion of the triphenylamine structure and the trifluorophenyl, and meanwhile, the electronegativity of F atoms is high, so that the polarity of molecules can be increased, and the hydrophobic performance can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to the application of 3,4,5-trifluorobromobenzene in electrical storage polymer coatings. Background Art

[0002] The new resistive random access memory (RRAM) is an electronic device that is completely different from traditional silicon-based semiconductor storage. It adopts a simple three-layer structure - electrode / active layer material / electrode, and is prepared from bottom to top. At present, the widely reported active layer materials of RRAM devices are mainly metals and their composites, organic small molecules and polymers. Polymer materials can not only regulate the storage performance of devices through chemical structure design, but also have good machinability, chemical resistance and radiation resistance. They are the best choice for active layer materials of RRAM devices.

[0003] The structure of polyimide (PI) contains a repeated conjugated system of imide aromatic rings, which has a strong structure, high thermal decomposition temperature, good film-forming properties, and excellent 3-D stacking ability, which makes it possible to prepare high-density storage devices. These excellent comprehensive properties come from the conjugation of the main chain and side chain of the PI molecule and the stacking of the molecular chain structure. The higher the degree of conjugation, the tighter the molecular chain stacking, the higher the thermal stability of PI, and the better the corrosion resistance. However, the strong interaction between the molecular chains will make PI less soluble and difficult to melt, resulting in poor flexibility and brittle cracking of the prepared PIs film. Introducing functional groups into PI can not only maintain the good thermal stability of PI, but also improve its organic solubility and processability. The F atom in the fluorinated group of 3,4,5-trifluorobromobenzene has a high electronegativity. Its introduction into the PIs structure can increase the polarity of the PIs molecule, and work together with the torsional motion of the trifluorophenyl group to improve the tight stacking of the PIs molecular chain, improve solubility, and thus improve processing performance. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a hyperbranched polyimide electrical storage polymer coating based on 3,4,5-trifluorophenyl, which has high solubility, good processing performance and low water absorption. The triphenylamine structure in the hyperbranched polyimide and the torsional motion of the trifluorophenyl group work together to improve the close stacking of the molecular chains. At the same time, the high electronegativity of the F atom can increase the polarity of the molecule and improve the hydrophobic performance.

[0005] The technical solution for achieving the purpose of the present invention is as follows:

[0006] Application of 3,4,5-trifluorobromobenzene in an electrical storage polymer coating, wherein the electrical storage polymer coating is a hyperbranched polyimide based on 3,4,5-trifluorophenyl prepared by a spin coating method; the hyperbranched polyimide is polymerized by a diamine compound containing 3,4,5-trifluorophenyl and a polyacid anhydride; the polyacid anhydride comprises two components A and B, the molar ratio of component A to component B is A / B=0-1, the component A is at least one of a dibasic acid anhydride, a tribasic acid anhydride and a tetrabasic acid anhydride; the component B is at least one of a tribasic acid anhydride and a tetrabasic acid anhydride; the tribasic acid anhydride and the tetrabasic acid anhydride have one or more of the following molecular structures of formula I, formula II and formula III:

[0007]

[0008] Preferably, the diamine compound containing 3,4,5-trifluorophenyl is one or more of the following molecular structures:

[0009]

[0010] More preferably, the diamine compound containing 3,4,5-trifluorophenyl has the following molecular structure:

[0011]

[0012] Specifically, the preparation method of the above molecular structure is as follows:

[0013] 1) At 0-5°C, add 2eq of 3,5-dinitrobenzoyl chloride and 2-3eq of triethylamine to a three-necked flask, add DMF to dissolve it, stir, add 1-1.5eq of m-aminophenylacetylene dropwise to the reaction bottle, add it over 10-20 minutes, raise the temperature to 70-80°C, react for 4-6 hours, cool to room temperature, pour a mixture of methanol and water into the reaction solution, the volume ratio of methanol to water is 2:1, solid precipitates, filter, wash the filter cake twice with sodium hydroxide solution, and recrystallize with methanol to obtain product 1;

[0014] 2) under nitrogen protection, disperse 1 eq of product 1 obtained in step 1) and 1 eq of 3,4,5-trifluorobromobenzene in a mixed solvent of piperidine and tetrahydrofuran, freeze-thaw degassing three times, add 0.03-0.08 eq of bistriphenylphosphine palladium dichloride, 0.08-0.12 eq of triphenylphosphine and 0.03-0.5 eq of cuprous iodide, react at 60-70° C. for 10-16 h, remove most of the solvent by rotary evaporation, wash the obtained solid with dilute hydrochloric acid at least twice, and then wash with methanol at least twice to obtain product 2;

[0015] 3) Under nitrogen protection, the product 2 obtained in step 2) is added to a three-necked flask, and then a mixed solution of ethanol and water is added, the temperature is raised to 45-55°C, 6-8eq iron powder and 20-30eq glacial acetic acid are added, the temperature is raised to 60-70°C and stirred for 2-3h, cooled to room temperature, filtered, and the obtained liquid is rotary evaporated to remove most of the ethanol, extracted with dichloromethane, and the obtained dichloromethane is washed once with ammonia water, the filtrate is dried over anhydrous magnesium sulfate, filtered, and the obtained filtrate is rotary evaporated to obtain the above molecular structure.

[0016] Preferably, the dibasic acid anhydride is one or more of pyromellitic anhydride, 3,3',4,4'-biphenyltetracarboxylic anhydride and hexafluorodianhydride.

[0017] More preferably, the dibasic acid anhydride is hexafluorodianhydride.

[0018] Preferably, the ternary acid anhydride is a molecular structure of formula I; the preparation method of the molecular structure of formula I is as follows:

[0019] S1. 1 eq of 4-nitroaniline and 1 eq of aniline are reacted in acetic acid solvent, refluxed for 4 to 6 hours, water is added to the mixture at room temperature, solids are recovered by filtration, washed with water at least twice, and the resulting mixture is dried under vacuum to obtain 4-nitro-n-phenylphthalimide;

[0020] S2. 1eq of 4-nitro-n-phenylphthalimide obtained in step S1, 3-5eq of ammonium formate, 0.1-0.15eq of palladium carbon, palladium content 10% ， The mixture of DMAc solvent is stirred at ambient temperature for 18 to 24 hours in a nitrogen atmosphere, the reaction mixture is filtered to remove palladium carbon, and the filtrate is added to cold water to obtain a precipitate, which is filtered, washed, and the crude product is recrystallized from methanol and dried to obtain 4-amino-n-phenylphthalimide;

[0021] S3. 1 eq of aniline and 1.1 to 1.3 eq of 4-bromoaniline were dissolved in DMF solvent, the resulting mixture was heated at 100 to 120° C. for 20 to 30 h, cooled to room temperature, the reaction mixture was diluted with water and filtered, washed, and dried to obtain the product 4-bromo-n-phenylphthalimide;

[0022] S4. Under nitrogen protection, 0.025-0.035 eq of palladium acetate, 0.040-0.045 eq of 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP), and 2.0-3.0 eq of cesium carbonate are dispersed in anhydrous toluene, and pre-catalyzed at 85-95° C. for 50-70 min. 2.5-3.0 eq of 4-amino-n-phenylphthalimide obtained in step S2 and 1.0 eq of 4-bromo-n-phenylphthalimide obtained in step S3 are dissolved in DMF and added to the system, and stirred at 115-120° C. for 2-3 d. The mixture is concentrated and rinsed with water, and then the precipitate is thoroughly washed with methanol to obtain a triphthalimide compound;

[0023] S5. Mix 1.0 eq of the triphthalimide compound obtained in step S4 with 15 to 30 eq of KOH in an EtOH / H2O solution with a volume ratio of 1:3 at a temperature of 80 to 100°C and stir for 6 to 10 hours. After the reaction is completed, add 1 to 2 mol / L of hydrochloric acid in an ice bath, filter and separate the precipitated white solid, wash with water and dry. Disperse the obtained solid in acetic anhydride solvent, reflux at 100 to 120°C for 20 to 30 hours, cool the obtained solid, wash with methanol, and dry to obtain a product with a molecular structure of formula I.

[0024] Preferably, the preparation method of the hyperbranched polyimide is as follows:

[0025] Under nitrogen protection, the diamine compound containing 3,4,5-trifluorophenyl and the polyacid anhydride are dispersed in DMF solvent, reacted at room temperature for 16 to 36 hours, and then a mixed solution of acetic anhydride and pyridine is added, reacted at 60 to 90° C. for 6 to 8 hours, cooled to room temperature, and the solution is poured into methanol, filtered to obtain a solid, washed with methanol at least twice, and dried to obtain a hyperbranched polyimide.

[0026] Preferably, the molar ratio of the diamine compound, the dibasic acid anhydride and the tribasic acid anhydride is (0.75-1.8):(0-1.5):(0.2-0.5); the volume ratio of acetic anhydride to pyridine is 1:1; and the alcohol is at least one of methanol and ethanol.

[0027] Beneficial Effects

[0028] The present invention has the following beneficial effects: a hyperbranched polyimide electrical storage polymer coating based on 3,4,5-trifluorophenyl is provided, and the coating has high solubility, good processing performance and low water absorption. A ternary acid anhydride and a diamine structure containing 3,4,5-trifluorophenyl are designed and synthesized with a triphenylamine structure as the core for copolymerization, wherein the triphenylamine structure and the torsional motion of 3,4,5-trifluorophenyl act together to improve the close stacking of molecular chains and improve the solubility, processing and film-forming properties of the hyperbranched polyimide. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the H-NMR spectrum of 4-nitro-n-phenylphthalimide of the present invention;

[0030] Figure 2 This is the H-NMR spectrum of 4-amino-n-phenylphthalimide of the present invention;

[0031] Figure 3 This is the H-NMR spectrum of 4-bromo-n-phenylphthalimide of the present invention;

[0032] Figure 4 This is the H-NMR spectrum of the triphthalimide compound of the present invention;

[0033] Figure 5 It is the nuclear magnetic hydrogen spectrum of the ternary acid anhydride of the present invention;

[0034] Figure 6 This is the synthesis route of the diamine compound 1 of the present invention;

[0035] Figure 7 This is the synthesis route of the ternary acid anhydride of the present invention;

[0036] Figure 8 The synthesis and structural schematic diagram of the hyperbranched polyimide 2 of the present invention.

[0037] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0039] The raw materials and equipment used in the embodiments and comparative examples are described as follows:

[0040] 3,4,5-Trifluorobromobenzene: Liaoning Xingfu New Materials;

[0041] 4-Nitrophthalic anhydride: Product No. 1091995, Shanghai Haohong Biopharmaceuticals;

[0042] Aniline: Product No. R006377, Shanghai E-En Chemical Technology;

[0043] Ammonium formate: Product No. 1085282, Shanghai Haohong Biopharmaceuticals;

[0044] Palladium on carbon: Product No. P992803, Shanghai MacLean Biochemical;

[0045] 4-Bromophthalic anhydride: Product No. 1066529, Shanghai Haohong Biopharmaceuticals;

[0046] Palladium acetate: Product No. P-01660, Tianjin Xiensi Biochemical Technology;

[0047] BINAP (1,1'-binaphthyl-2,2'-bis(diphenylphosphine): Catalog No. 1047644, Shanghai Haohong Biopharmaceuticals;

[0048] Cesium carbonate: Product No. C-35184, Tianjin Xiensi Biochemical Technology;

[0049] 3,5-Dinitrobenzoyl chloride: D100649, Shanghai Aladdin Reagent;

[0050] m-Aminophenylacetylene: Product No. 1035182, Shanghai Haohong Biopharmaceuticals;

[0051] Bistriphenylphosphine palladium dichloride: Product No. 1020950, Shanghai Haohong Biopharmaceuticals;

[0052] Triphenylphosphine: Product No. R012637, Shanghai Yien Chemical Technology;

[0053] Cuprous iodide: Product No. C804587, Shanghai MacLean Biochemical;

[0054] Hexafluorodianhydride: Product No. H810819, Shanghai MacLean Biochemical.

[0055] Diamine compound 1 (self-made)

[0056]

[0057] 1) At 0-5°C, add 2 mol of 3,5-dinitrobenzoyl chloride and 3 mol of triethylamine to a three-necked flask, add DMF to dissolve it, stir, add 1.5 eq of m-aminophenylacetylene dropwise to the reaction bottle, add it in 15 min, raise the temperature to 80°C, react for 6 h, cool to room temperature, pour a mixture of methanol and water (the volume ratio of methanol to water is 2:1) into the reaction solution, solid precipitates, filter, wash the filter cake with sodium hydroxide solution 3 times, and recrystallize with methanol to obtain product 1;

[0058] 2) under nitrogen protection, 1 mol of the product 1 obtained in step 1) and 1 mol of 3,4,5-trifluorobromobenzene were dispersed in a mixed solvent of piperidine and tetrahydrofuran, and the mixture was freeze-thawed for three times for degassing. 0.04 mol of bistriphenylphosphine palladium dichloride, 0.10 mol of triphenylphosphine and 0.03 mol of cuprous iodide were added, and the mixture was reacted at 70° C. for 14 h. Most of the solvent was removed by rotary evaporation. The obtained solid was washed with dilute hydrochloric acid for three times and then with methanol for three times to obtain product 2;

[0059] 3) Under nitrogen protection, 1 mol of product 2 obtained in step 2) was added to a three-necked flask, and then a mixed solution of ethanol and water was added, the temperature was raised to 50°C, 6 mol of iron powder and 25 mol of glacial acetic acid were added, the temperature was raised to 70°C and stirred for 3 h, the mixture was cooled to room temperature, and the mixture was filtered with suction. Most of the ethanol was removed by rotary evaporation of the obtained liquid, and the mixture was extracted with dichloromethane. The obtained dichloromethane was washed once with aqueous ammonia, the filtrate was dried over anhydrous magnesium sulfate, and the mixture was filtered with suction. The obtained filtrate was rotary evaporated to obtain diamine compound 1.

[0060] Diamine compound 2 (self-made)

[0061]

[0062] Compared with the preparation method of the diamine compound 1, the difference is that 1 mol of 3,4,5-trifluorobromobenzene in step 2) is replaced by 1 mol of bromobenzene.

[0063] Tribasic anhydride (homemade)

[0064]

[0065] S1. 1 mol of 4-nitroaniline and 1 mol of aniline are reacted in acetic acid solvent, refluxed for 4 to 6 hours, water is added to the mixture at room temperature, solids are recovered by filtration, washed with water at least twice, and dried under vacuum to obtain 4-nitro-n-phenylphthalimide;

[0066] S2. A mixture of 1 mol of 4-nitro-n-phenylphthalimide obtained in step S1, 5 mol of ammonium formate, 0.15 eq of palladium carbon (palladium content 10%) and DMAc solvent was stirred at ambient temperature for 24 h in a nitrogen atmosphere, the reaction mixture was filtered to remove the palladium carbon, and the filtrate was added to cold water to obtain a precipitate, and the crude product was filtered, washed, and recrystallized from methanol and dried to obtain 4-amino-n-phenylphthalimide;

[0067] S3. 1 mol of aniline and 1.3 mol of 4-bromoaniline were dissolved in DMF solvent, the resulting mixture was heated at 120° C. for 30 h, cooled to room temperature, the reaction mixture was diluted with water and filtered, washed, and dried to obtain the product 4-bromo-n-phenylphthalimide;

[0068] S4. Under nitrogen protection, 0.025 mol of palladium acetate, 0.045 mol of BINAP, and 3.0 mol of cesium carbonate are dispersed in anhydrous toluene, and pre-catalyzed at 90° C. for 60 min. 2.5 mol of 4-amino-n-phenylphthalimide obtained in step S2 and 1.0 mol of 4-bromo-n-phenylphthalimide obtained in step S3 are dissolved in DMF and added to the system, and stirred at 120° C. for 3 d. The mixture is concentrated and rinsed with water, and then the precipitate is thoroughly washed with methanol to obtain a triphthalimide compound;

[0069] S5. Mix 1.0 eq of the triphthalimide compound obtained in step S4 with 15-30 eq of KOH in an EtOH / H2O (1:3) solution at 100°C and stir for 10 hours. After the reaction is completed, add hydrochloric acid (2 mol / l) in an ice bath, filter and separate the precipitated white solid, wash with water and dry. Disperse the obtained solid in acetic anhydride solvent, reflux at 120°C for 30 hours, cool the obtained solid, wash with methanol, and dry to obtain a ternary acid anhydride.

[0070] Hyperbranched polyimide 1

[0071] Under nitrogen protection, 1.8 mol of diamine compound 1, 1.5 mol of hexafluorodianhydride and 0.2 mol of tribasic anhydride were dispersed in DMF solvent, reacted at room temperature for 36 hours, and then a mixed solution of acetic anhydride and pyridine in a volume ratio of 1:1 was added, and reacted at 80°C for 8 hours. After cooling to room temperature, the solution was poured into methanol, filtered to obtain a solid, washed with methanol 3 times, and dried to obtain hyperbranched polyimide 1.

[0072] Hyperbranched polyimide 2

[0073] Under nitrogen protection, 0.75 mol of diamine compound 1 and 0.5 mol of tribasic acid anhydride were dispersed in DMF solvent, reacted at room temperature for 36 hours, and then a mixed solution of acetic anhydride and pyridine in a volume ratio of 1:1 was added, and reacted at 80°C for 8 hours. After cooling to room temperature, the solution was poured into methanol, filtered to obtain a solid, washed with methanol 3 times, and dried to obtain hyperbranched polyimide 2.

[0074] Hyperbranched polyimide 3

[0075] The preparation method is different from that of the hyperbranched polyimide 1 in that 1.8 mol of the diamine compound 1 is replaced by 1.8 mol of the diamine compound 2.

[0076] Linear polyimide 1

[0077] The preparation method is different from that of the hyperbranched polyimide 1 in that 0.2 mol of ternary acid anhydride is replaced by 0.3 mol of hexafluorodianhydride.

[0078] Preparation of storage devices based on hyperbranched polyimide: 20 mg of hyperbranched polyimide was dissolved in 10 mL of DMAc, filtered through a polytetrafluoroethylene membrane, spin-coated on ITO, dried at 80°C in vacuum, and an Al electrode was deposited on it by masked vacuum thermal evaporation to prepare a three-layer structure of Al / PIs / ITO.

[0079] The following is the test method of the performance parameters involved in the present invention:

[0080] Water absorption: Add DMAc solution (0.4 g / mL) of hyperbranched polyimide on the ITO surface at 70 °C

[0081] Vacuum drying, weighing W d Then immerse the prepared sample in deionized water for 24 h, wipe dry, and weigh W w , by W u (%) = [(W w -W d ) / W d ]×100%, repeat the experiment three times and take the average value;

[0082] Solubility: Solubility test of hyperbranched polyimide in different solvents and at different temperatures;

[0083] Storage performance test: Test retention time It curve at 25℃ and 150℃, cycle 10 4 s.

[0084] Table 1 Characterization and performance test of hyperbranched polyimide

[0085] Hyperbranched polyimide 1 Hyperbranched polyimide 2 Hyperbranched polyimide 3 Linear polyimide 1 Number average molecular weight 28542 26423 23678 25974 Water absorption (%) 0.59 0.63 0.95 0.72 NMP Dissolve at room temperature Dissolve at room temperature Heat to dissolve Heat to dissolve DMAc Dissolve at room temperature Dissolve at room temperature Dissolve at room temperature Heat to dissolve DMF Dissolve at room temperature Dissolve at room temperature Dissolve at room temperature Heat to dissolve m-Cresol Slightly soluble by heating Heat to dissolve Slightly soluble by heating Insoluble in water THF Slightly soluble by heating Slightly soluble by heating Insoluble in water Insoluble in water <![CDATA[CHCl3]]> Slightly soluble by heating Slightly soluble by heating Insoluble in water Insoluble in water DMSO Dissolve at room temperature Dissolve at room temperature Dissolve at room temperature Heat to dissolve

[0086] In Table 1, NMP is N-methylpyrrolidone, DMAc is N,N-dimethylacetamide, DMF is N,N-dimethylformamide, m-Cresol is m-cresol, THF is tetrahydrofuran, and DMSO is dimethyl sulfoxide.

[0087] Table 2 Storage performance test of storage devices

[0088]

[0089]

[0090] As shown in the data of Table 1, hyperbranched polyimide 1 and 2 have lower water absorption and better solubility. Among them, hyperbranched polyimide 1 has the lowest water absorption because it contains more hexafluorodianhydride with hydrophobic structure. Hyperbranched polyimide 2 has the best solubility. The torsional movement of more triphenylamine structures in the molecule changes its stacking mode in the solution. Hyperbranched polyimide 3 has poor solubility and high water absorption because of the loss of F atoms. Although linear polyimide 1 has more hexafluorodianhydride structures, it does not have the dense stacking of branched structures in the solid state, so its water absorption is higher than that of hyperbranched polyimide 1 and 2, and its solubility is worse than that of hyperbranched polyimide 1, 2, and 3.

[0091] It can be seen from the data in Table 2 that the storage performance of the prepared storage devices is very stable.

[0092] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. Application of 3,4,5-trifluorobromobenzene in electrical storage polymer coating, characterized in that: The electrical storage polymer coating is a hyperbranched polyimide based on 3,4,5-trifluorophenyl prepared by spin coating; the hyperbranched polyimide is polymerized by a diamine compound containing 3,4,5-trifluorophenyl and a polyacid anhydride; the polyacid anhydride comprises two components A and B, the molar ratio of component A to component B is A / B=0-1, the component A is at least one of a dibasic acid anhydride, a tribasic acid anhydride and a tetrabasic acid anhydride; the component B is at least one of a tribasic acid anhydride and a tetrabasic acid anhydride; the tribasic acid anhydride and the tetrabasic acid anhydride have one or more of the following molecular structures of formula I, formula II and formula III:

2. The use of 3,4,5-trifluorobromobenzene in an electrical storage polymer coating as claimed in claim 1, characterized in that: The diamine compound containing 3,4,5-trifluorophenyl is one or more of the following molecular structures:

3. The use of 3,4,5-trifluorobromobenzene in an electrical storage polymer coating according to claim 1, characterized in that: The dibasic acid anhydride is one or more of pyromellitic anhydride, 3,3',4,4'-biphenyltetracarboxylic anhydride and hexafluorodianhydride.

4. The use of 3,4,5-trifluorobromobenzene in an electrical storage polymer coating as claimed in claim 1, characterized in that: The ternary acid anhydride has a molecular structure of formula I; the preparation method of the molecular structure of formula I is as follows: S1. 1 eq of 4-nitrophthalic anhydride and 1 eq of aniline are reacted in acetic acid solvent, refluxed for 4 to 6 hours, water is added to the mixture at room temperature, the solid is recovered by filtration, washed with water at least twice, and dried under vacuum to obtain 4-nitro-n-phenylphthalimide; S2. A mixture of 1 eq of 4-nitro-n-phenylphthalimide obtained in step S1, 3 to 5 eq of ammonium formate, 0.1 to 0.15 eq of palladium carbon and DMAc solvent is stirred at 20 to 25° C. for 18 to 24 h in a nitrogen atmosphere, the reaction mixture is filtered to remove the palladium carbon, and the filtrate is added to cold water to obtain a precipitate, and the crude product is filtered, washed, and recrystallized from methanol and dried to obtain 4-amino-n-phenylphthalimide; S3. 1 eq of aniline and 1.1 to 1.3 eq of 4-bromophthalic anhydride were dissolved in DMF solvent, the resulting mixture was heated at 100 to 120° C. for 20 to 30 h, cooled to room temperature, the reaction mixture was diluted with water and filtered, washed, and dried to obtain the product 4-bromo-n-phenylphthalimide; S4. Under nitrogen protection, 0.025-0.035 eq of palladium acetate, 0.040-0.045 eq of BINAP, and 2.0-3.0 eq of cesium carbonate are dispersed in anhydrous toluene, and pre-catalyzed at 85-95° C. for 50-70 min. Then, 2.5-3.0 eq of 4-amino-n-phenylphthalimide obtained in step S2 and 1.0 eq of 4-bromo-n-phenylphthalimide obtained in step S3 are dissolved in DMF and added to the system, and stirred at 115-120° C. for 2-3 d. The mixture is concentrated and rinsed with water, and then the precipitate is thoroughly washed with methanol to obtain a triphthalimide compound; S5. Mix 1.0 eq of the triphthalimide compound obtained in step S4 with 15-30 eq of KOH in an EtOH / H2O solution at a temperature of 80-100°C and stir for 6-10 hours. After the reaction is completed, add 1-2 mol / L hydrochloric acid in an ice bath, filter and separate the precipitated white solid, wash with water and dry. The obtained solid is dispersed in acetic anhydride solvent and refluxed at 100-120°C for 20-30 hours. The obtained solid is cooled, washed with methanol, and dried to obtain a product with a molecular structure of formula I.

5. The use of 3,4,5-trifluorobromobenzene in an electrical storage polymer coating as claimed in claim 1, characterized in that: The preparation method of the hyperbranched polyimide is as follows: Under nitrogen protection, the diamine compound containing 3,4,5-trifluorophenyl, dibasic acid anhydride and tribasic acid anhydride are dispersed in DMF solvent, reacted at room temperature for 16 to 36 hours, and then a mixed solution of acetic anhydride and pyridine is added, reacted at 60 to 90° C. for 6 to 8 hours, cooled to room temperature, and the solution is poured into alcohol, filtered to obtain a solid, washed with methanol for at least 2 times, and dried to obtain a hyperbranched polyimide.

6. The use of 3,4,5-trifluorobromobenzene in an electrical storage polymer coating as claimed in claim 5, characterized in that: The molar ratio of the diamine compound, the dibasic acid anhydride and the tribasic acid anhydride is (0.75-1.8):(0-1.5):(0.2-0.5); the volume ratio of acetic anhydride to pyridine is 1:1; and the alcohol is at least one of methanol and ethanol.

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