High temperature chemical resistant polyimide film and method of making same
By synergistic modification of triethanolamine and piperazine and regulation by organic small molecules, the high-temperature and chemical corrosion performance of polyimide films is improved, solving the problem of insufficient stability of existing films under high-temperature and chemical corrosion environments, and achieving an overall performance improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YANGZHOU YINGDI NEW MATERIAL TECH CO LTD
- Filing Date
- 2026-04-27
- Publication Date
- 2026-05-29
AI Technical Summary
Existing polyimide films lack structural stability under high temperature and chemical corrosion environments, and the modification methods are limited and difficult to balance process stability and overall performance improvement.
Triethanolamine and piperazine were used to synergistically modify polyamic acid, constructing a synergistically modified polyamic acid system. During polymerization, film formation and heat treatment, hydrogen bonds and intermolecular forces were formed to improve the stability of the molecular chain. The organic small molecule functional regulator N-methylpyrrolidone was introduced to participate in intermolecular regulation.
It significantly improves the structural stability and overall performance of polyimide films under high temperature and chemical corrosion environments, while maintaining good mechanical and electrical insulation properties. The process is simple and compatible with existing industrial production.
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Figure CN122103892A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer functional materials technology, specifically to a high-temperature chemically resistant polyimide film and its preparation method. Background Technology
[0002] Polyimide films are widely used in electronic and electrical insulation, flexible electronics, high-temperature structural materials, and aerospace fields due to their excellent high-temperature resistance, mechanical properties, electrical insulation properties, and good chemical stability. Especially in harsh environments such as high temperature, strong acids and alkalis, or organic solvents, polyimide films are often used as key functional materials, placing higher demands on their overall stability.
[0003] Existing polyimide films are typically prepared using polyamic acid as a precursor, which is polymerized and then subjected to imidization via heat treatment. While this preparation process is mature and highly industrialized, it still has certain shortcomings in practical applications. On the one hand, conventional polyamic acid systems are easily affected by high temperatures and chemical media during polymerization, film formation, and imidization, resulting in insufficient molecular chain stability and performance degradation of the film under long-term high-temperature or chemical corrosion conditions. On the other hand, existing technologies mostly focus on improving performance by adjusting the polyimide backbone structure or introducing a single modifying component. These modification methods are relatively limited and make it difficult to achieve a synergistic improvement in both high-temperature resistance and chemical corrosion resistance while maintaining process stability.
[0004] Some modification methods require the introduction of complex chemical reactions or additional post-processing steps, which not only increases the complexity of the process but also hinders its direct application in existing polyimide film production lines. Therefore, how to improve the overall performance of polyimide films under high temperature and chemical corrosion environments through reasonable and effective synergistic modification of polyamic acid precursors without significantly altering existing polyimide film preparation processes remains a pressing technical problem to be solved in this field. Summary of the Invention
[0005] To overcome the problems of insufficient structural stability of existing polyimide films under high temperature and chemical corrosion environments, limited modification methods, and difficulty in simultaneously improving process stability and overall performance, the present invention aims to provide a high-temperature chemically resistant polyimide film and its preparation method, achieving a synergistic improvement in both high-temperature resistance and chemical corrosion resistance without significantly altering existing polyimide film preparation processes. This invention uses polyamic acid as a precursor, synergistically modifying it with two small organic molecules, triethanolamine and piperazine, to construct a synergistically modified polyamic acid system. Based on this system, an imidization reaction is completed through polymerization, film formation, and heat treatment to obtain a high-temperature chemically resistant polyimide film. This invention significantly improves the structural stability and overall performance of the polyimide film under high temperature and chemical corrosion environments through synergistic modification of the polyamic acid precursor.
[0006] The objective of this invention can be achieved through the following technical solutions:
[0007] A high-temperature chemically resistant polyimide film, comprising the following raw materials in parts by weight: 85-95 parts of synergistically modified polyamic acid; 0.1-3.0 parts of organic small molecule functional regulator; 50-150 parts of solvent; 0.05-1.0 parts of antioxidant; and 0.05-1.0 parts of stabilizer. The synergistically modified polyamic acid is a polyimide precursor material obtained by synergistic modification of polyamic acid with two organic small molecules, triethanolamine and piperazine. Triethanolamine forms hydrogen bonds with the carboxyl and amide groups in the polyamic acid molecule, while piperazine regulates the conformation and intermolecular force distribution between polyamic acid molecular chains. The synergistic effect of these two molecules improves the structural stability of the polyamic acid system under high temperature and chemical media conditions. The organic small molecule functional regulator is N-methylpyrrolidone, which, while acting as a solvent, participates in the intermolecular regulation process of the synergistically modified polyamic acid system at the molecular scale, thereby further enhancing the high-temperature resistance and chemical corrosion resistance of the obtained polyimide film.
[0008] Optionally, the synergistically modified polyamic acid comprises the following raw materials in parts by weight: 88-96 parts of polyamic acid; 0.5-4.0 parts of triethanolamine; 0.1-2.0 parts of piperazine; 0.05-0.5 parts of 2,6-di-tert-butyl-4-methylphenol; and 0.05-0.5 parts of triphenyl phosphate.
[0009] Optionally, the preparation method of synergistically modified polyamic acid includes the following steps:
[0010] (1) Add polyamic acid to a solvent and disperse and dissolve it under stirring to obtain a homogeneous polyamic acid solution;
[0011] (2) Triethanolamine, piperazine, 2,6-di-tert-butyl-4-methylphenol and triphenyl phosphate were added sequentially to the polyamic acid solution, and synergistic modification was carried out under temperature control and stirring conditions to obtain a synergistically modified polyamic acid system.
[0012] (3) Continue stirring the synergistic modified polyamic acid system until the system is stable to obtain the synergistic modified polyamic acid.
[0013] Optionally, the reaction conditions in step (1) are: dissolution at 20-40°C, stirring speed of 50-300 r / min, and dissolution time of 30-120 min; the solvent in step (1) is selected from one or more of N-methylpyrrolidone and dimethylformamide.
[0014] Optionally, the reaction conditions in step (2) are synergistic modification treatment at 40-70℃, stirring speed of 100-500 r / min, and reaction time of 30-180 min.
[0015] Optionally, the reaction conditions in step (3) are to continue stirring at 30-60°C, with a stirring speed of 50-200 r / min and a processing time of 20-120 min.
[0016] Optionally, the solvent is a mixture of N-methylpyrrolidone and dimethylformamide in a mass ratio of (5-9):(1-5); the antioxidant is a mixture of 2,6-di-tert-butyl-4-methylphenol and tris[2,4-di-tert-butylphenyl]phosphite in a mass ratio of (1-5):(1-5); and the stabilizer is a mixture of triphenyl phosphate and triphenyl phosphite in a mass ratio of (1-5):(1-5).
[0017] Optionally, a method for preparing a high-temperature chemically resistant polyimide film includes the following steps:
[0018] S1, the synergistically modified polyamic acid system is polymerized under stirring conditions to obtain a synergistically modified polyamic acid system for membrane preparation;
[0019] S2, the synergistically modified polyamic acid system used for membrane preparation is dried and heat-treated to induce an imidization reaction in the synergistically modified polyamic acid, thereby obtaining a polyimide film;
[0020] S3, the polyimide film is cut and tested to obtain the finished high-temperature chemically resistant polyimide film.
[0021] Optionally, the reaction conditions in step S1 are as follows: the polymerization reaction is carried out in a reactor, the reaction temperature is controlled at 30-68℃, the reaction pressure is controlled at 1-10MPa, and the stirring speed is controlled at 5-300r / min during the reaction.
[0022] Optionally, the reaction conditions for step S2 are to dry the synergistically modified polyamic acid system at 80–200°C and then heat-treat it at 200–380°C to complete the imidization reaction; the reaction conditions for step S3 are to cool the obtained polyimide film at 20–40°C and then cut and inspect it at this temperature.
[0023] The beneficial effects of this invention are:
[0024] This invention synergistically modifies polyamic acid precursors by introducing triethanolamine and piperazine. Without altering the chemical structure of the polyimide backbone, it effectively regulates the intermolecular forces and spatial conformation of the polyamic acid molecules, enabling the precursor system to maintain higher structural stability during polymerization, film formation, and imidization. This significantly reduces the destructive effects of high temperatures and chemical media on the molecular chains. The resulting polyimide film exhibits minimal performance degradation at high temperatures and maintains good mechanical and electrical insulation properties under the influence of acids, alkalis, and organic solvents. Furthermore, this synergistic modification method is simple, highly compatible with existing industrial production processes, and offers significant advantages for engineering applications. Attached Figure Description
[0025] The invention will now be further described with reference to the accompanying drawings.
[0026] Figure 1 A comparison of the infrared spectra of polyamic acid and synergistically modified polyamic acid;
[0027] Figure 2 A comparison chart of tensile strength test results for samples with different proportions. Detailed Implementation
[0028] The present invention will be further described below with reference to specific embodiments. However, the present invention is not limited to the following embodiments. Equivalent adjustments made without departing from the spirit and essence of the present invention should also be considered to fall within the protection scope of the present invention.
[0029] Example 1:
[0030] The purpose is to verify that when the dosage of each component and the reaction conditions are taken at the lower limit of the allowable range of the claims, the synergistic modified polyamic acid system can still be stably prepared and a polyimide film with high temperature resistance and chemical corrosion resistance can be obtained.
[0031] Preparation method
[0032] S1, Preparation of synergistically modified polyamic acid
[0033] Weigh out 88 parts by weight of polyamic acid, 0.5 parts by weight of triethanolamine, 0.1 parts by weight of piperazine, 0.05 parts by weight of 2,6-di-tert-butyl-4-methylphenol, and 0.05 parts by weight of triphenyl phosphate. Add the above polyamic acid to a solvent prepared by mixing N-methylpyrrolidone and dimethylformamide in a mass ratio of 5:1. Stir and disperse at 20°C with a stirring speed of 50 r / min for 30 min to obtain a homogeneous polyamic acid solution. Then, add triethanolamine, piperazine, 2,6-di-tert-butyl-4-methylphenol, and triphenyl phosphate in sequence. Perform synergistic modification treatment at 40°C with a stirring speed of 100 r / min for 30 min. Continue stirring at 30°C for 20 min to stabilize the system and obtain synergistically modified polyamic acid.
[0034] S2, imidization treatment
[0035] The synergistically modified polyamic acid system was dried at 80°C and then heat-treated at 200°C to induce an imidization reaction, thereby obtaining a polyimide film.
[0036] S3, Post-processing
[0037] The obtained polyimide film was cooled at 20°C, and then cut and tested to obtain a high-temperature chemically resistant polyimide film product.
[0038] Example 2:
[0039] The purpose is to verify the stability of the synergistically modified polyamic acid system and the overall performance of the resulting polyimide film when the proportions of each component and the reaction conditions are taken as the median of the claims.
[0040] Preparation method
[0041] S1, Preparation of synergistically modified polyamic acid
[0042] Weigh out 92 parts by weight of polyamic acid, 2.0 parts by weight of triethanolamine, 1.0 part by weight of piperazine, 0.25 parts by weight of 2,6-di-tert-butyl-4-methylphenol, and 0.25 parts by weight of triphenyl phosphate. Add the polyamic acid to a solvent composed of N-methylpyrrolidone and dimethylformamide in a mass ratio of 7:3. Disperse the solution by stirring at 30°C for 150 rpm for 60 min to obtain a polyamic acid solution. Then, add triethanolamine, piperazine, 2,6-di-tert-butyl-4-methylphenol, and triphenyl phosphate sequentially. Perform synergistic modification treatment at 55°C for 90 min by stirring at 300 rpm. Continue stirring at 45°C for 60 min to stabilize the system, obtaining synergistically modified polyamic acid. Figure 1 A comparison of the infrared spectra before and after modification shows that polyamic acid before modification mainly exhibits characteristic absorption peaks of carboxyl and amide groups, with the peaks occurring in the 3600–3200 cm⁻¹ range. -1 The absorption peaks of hydroxyl and amino groups at 1720 cm⁻¹ are relatively weak. -1 The C=O absorption peaks of the carboxyl groups around the left and right are quite obvious; after synergistic modification with triethanolamine and piperazine, the absorption peak at 3400 cm⁻¹ is more pronounced. -1 The nearby broad peaks are significantly enhanced, and the area between 2950 and 2850 cm is also significantly enhanced. -1 aliphatic C–H and 1320–1200 cm -1 The increased intensity of C–N and C–O absorption peaks in the region indicates the introduction of new intermolecular interactions during the modification process; the absence of new covalent bond characteristic peaks before and after modification suggests that the synergistic modification is mainly achieved through hydrogen bonds and intermolecular interactions, thereby improving the structural stability of the polyamic acid system.
[0043] S2, imidization treatment
[0044] The synergistically modified polyamic acid system was dried at 140°C and then heat-treated at 300°C to complete the imidization reaction, thereby obtaining a polyimide film.
[0045] S3, Post-processing
[0046] The obtained polyimide film was cooled at 30°C, and then cut and tested to obtain a high-temperature chemically resistant polyimide film product.
[0047] Example 3:
[0048] The purpose is to verify the feasibility of synergistic modification of the polyamic acid system and the stability of the polyimide film under high temperature and chemical corrosion environments when the dosage of each component and the reaction conditions are taken at the upper limit of the claims.
[0049] Preparation method
[0050] S1, Preparation of synergistically modified polyamic acid
[0051] Weigh out 96 parts by weight of polyamic acid, 4.0 parts by weight of triethanolamine, 2.0 parts by weight of piperazine, 0.5 parts by weight of 2,6-di-tert-butyl-4-methylphenol, and 0.5 parts by weight of triphenyl phosphate. Add the polyamic acid to a solvent composed of N-methylpyrrolidone and dimethylformamide in a mass ratio of 9:5. Disperse the mixture at 40°C with stirring at 300 r / min for 120 min. Then add triethanolamine, piperazine, 2,6-di-tert-butyl-4-methylphenol, and triphenyl phosphate in sequence. Perform synergistic modification treatment at 70°C with stirring at 500 r / min for 180 min. Continue stirring at 60°C for 120 min to stabilize the system and obtain synergistically modified polyamic acid.
[0052] S2, imidization treatment
[0053] The synergistically modified polyamic acid system was dried at 200°C and then heat-treated at 380°C to induce an imidization reaction, thereby obtaining a polyimide film.
[0054] S3, Post-processing
[0055] The obtained polyimide film was cooled at 40°C, and then cut and tested to obtain a high-temperature chemically resistant polyimide film product.
[0056] Comparative Example 1:
[0057] The purpose is to verify the effect of changing the polyamic acid from "synergistic modification by two small organic molecules" to "single modification by triethanolamine only" on the stability of the synergistically modified polyamic acid system and the overall performance of the resulting polyimide film.
[0058] Preparation method
[0059] S1, Preparation of synergistically modified polyamic acid
[0060] Weigh out 92 parts by weight of polyamic acid, 2.0 parts by weight of triethanolamine, 0.25 parts by weight of 2,6-di-tert-butyl-4-methylphenol, and 0.25 parts by weight of triphenyl phosphate. Add the polyamic acid to a solvent composed of N-methylpyrrolidone and dimethylformamide in a mass ratio of 7:3. Disperse the solution by stirring at 30°C and 150 r / min for 60 min to obtain a polyamic acid solution. Then add triethanolamine, 2,6-di-tert-butyl-4-methylphenol, and triphenyl phosphate. Modify the solution at 55°C and 300 r / min for 90 min. Continue stirring at 45°C for 60 min to stabilize the system and obtain a single modified polyamic acid.
[0061] S2, imidization treatment
[0062] The single modified polyamic acid system was dried at 140°C and then heat-treated at 300°C to complete the imidization reaction, thereby obtaining a polyimide film.
[0063] S3, Post-processing
[0064] The obtained polyimide film was cooled at 30°C, and then cut and inspected to obtain the finished polyimide film.
[0065] Comparative Example 2:
[0066] The purpose is to verify the effect of changing the polyamic acid modification method from "synergistic modification by two small organic molecules" to "single modification by piperazine only" on the stability of the modified polyamic acid system and the overall performance of the resulting polyimide film.
[0067] Preparation method
[0068] S1, Preparation of synergistically modified polyamic acid
[0069] Weigh out 92 parts by weight of polyamic acid, 1.0 part by weight of piperazine, 0.25 parts by weight of 2,6-di-tert-butyl-4-methylphenol, and 0.25 parts by weight of triphenyl phosphate. Add the polyamic acid to a solvent composed of N-methylpyrrolidone and dimethylformamide in a mass ratio of 7:3. Disperse the solution by stirring at 30°C and 150 r / min for 60 min to obtain a polyamic acid solution. Then add piperazine, 2,6-di-tert-butyl-4-methylphenol, and triphenyl phosphate. Modify the solution at 55°C and 300 r / min for 90 min. Then continue stirring at 45°C for 60 min to stabilize the system and obtain a single modified polyamic acid.
[0070] S2, imidization treatment
[0071] The single modified polyamic acid system was dried at 140°C and then heat-treated at 300°C to complete the imidization reaction, thereby obtaining a polyimide film.
[0072] S3, Post-processing
[0073] The obtained polyimide film was cooled at 30°C, and then cut and inspected to obtain the finished polyimide film.
[0074] Comparative Example 3:
[0075] The aim is to verify the effect of removing the intermolecular regulatory effect of the organic small molecule functional regulator on the polyamic acid synergistic modification system while keeping the polyamic acid synergistic modification system unchanged, thereby affecting the overall performance of the obtained polyimide film.
[0076] Preparation method
[0077] S1, Preparation of synergistically modified polyamic acid
[0078] Weigh out 92 parts by weight of polyamic acid, 2.0 parts by weight of triethanolamine, 1.0 part by weight of piperazine, 0.25 parts by weight of 2,6-di-tert-butyl-4-methylphenol, and 0.25 parts by weight of triphenyl phosphate. Add polyamic acid to dimethylformamide solvent and stir to disperse at 30°C with a stirring speed of 150 r / min for 60 min to obtain a polyamic acid solution. Then add triethanolamine, piperazine, 2,6-di-tert-butyl-4-methylphenol, and triphenyl phosphate in sequence and carry out synergistic modification treatment at 55°C with a stirring speed of 300 r / min for 90 min. Then continue stirring at 45°C for 60 min to stabilize the system and obtain synergistically modified polyamic acid.
[0079] S2, imidization treatment
[0080] The synergistically modified polyamic acid system was dried at 140°C and then heat-treated at 300°C to complete the imidization reaction, thereby obtaining a polyimide film.
[0081] S3, Post-processing
[0082] The obtained polyimide film was cooled at 30°C, and then cut and inspected to obtain the finished polyimide film.
[0083] Performance testing:
[0084] 1. Tensile strength test method
[0085] Samples were cut from the polyimide films obtained in Examples 1, 2, and 3, as well as Comparative Examples 1-3, in the same direction and with the same dimensions, avoiding defective areas at the film edges. The samples were then placed in a constant temperature and humidity environment until they stabilized. Tensile tests were performed on the samples using a universal testing machine, with the same clamping method and tensile speed. At least five parallel samples were tested for each group of samples. The tensile strength data at fracture of each sample were recorded, and the results of the parallel samples were statistically compared to evaluate the differences in mechanical properties between the different samples.
[0086] 2. Insulation resistance test method
[0087] The polyimide films obtained in Examples 1, 2, and 3, as well as Comparative Examples 1-3, were cut into test pieces of the same area, ensuring that the sample surfaces were clean and free of obvious defects. The samples were then subjected to equilibration treatment under specified environmental conditions. Insulation resistance was tested on each group of samples using an insulation resistance tester under the same electrode configuration, applied voltage, and test time. Measurements were taken at multiple different locations for each sample, and the test results were statistically analyzed to compare the electrical insulation performance of different samples.
[0088] 3. Dielectric constant testing method
[0089] The polyimide films obtained in Examples 1, 2, and 3, as well as Comparative Examples 1-3, were prepared as samples meeting the requirements for dielectric testing. The samples were ensured to have uniform thickness and neat edges, and were dried and equilibrated before testing. The dielectric constant of each group of samples was measured using a dielectric constant meter under the same testing frequency and conditions. At least three different locations were selected for testing each sample, and the test results were statistically compared to evaluate the influence of different modification methods on the dielectric properties of the polyimide films.
[0090] 4. Temperature resistance test method
[0091] The polyimide film samples obtained in Examples 1, 2, and 3, as well as Comparative Examples 1-3, were subjected to temperature resistance tests. Thermogravimetric analysis (TGA) was used to heat the samples under the same heating rate and atmospheric conditions, and the temperatures at which obvious thermal decomposition characteristics appeared were recorded to characterize the thermal decomposition performance of the samples. Simultaneously, differential scanning calorimetry (DSC) or dynamic thermomechanical analysis (TMA) was used to test the samples under the same heating program and test conditions to obtain the glass transition temperatures. The differences in high-temperature stability were evaluated by comparing the test results of different samples.
[0092] 5. Test methods for chemical corrosion resistance
[0093] Polyimide films obtained in Examples 1, 2, and 3, as well as Comparative Examples 1-3, were cut into samples of the same size. Their initial appearance was recorded, and their initial thickness, tensile strength, and insulation resistance were measured as control data. The samples were then immersed in acidic, alkaline, and organic solvent media under the same temperature and immersion time conditions. After immersion, the samples were removed, their surfaces were cleaned, and dried until stable. The appearance of the immersed samples was then re-inspected, and their thickness, tensile strength, and insulation resistance were re-measured under the same test conditions. By comparing the changes in appearance and performance retention before and after immersion, the chemical corrosion resistance of different samples was evaluated.
[0094] Table 1 Performance test results of polyimide films from different embodiments and comparative examples.
[0095] Sample number Tensile strength (MPa) Insulation resistance Ω Dielectric constant Thermal decomposition temperature (°C) Performance retention after chemical corrosion Example 1 128 1.6×10¹³ 3.45 515 Slight changes, performance remains largely unchanged Example 2 142 2.3×10¹³ 3.30 535 Stable appearance and highest performance retention rate Example 3 135 1.9×10¹³ 3.38 525 Minor changes, good performance maintained Comparative Example 1 112 7.8×10¹² 3.62 485 It turns white and its performance is significantly reduced. Comparative Example 2 108 6.9×10¹² 3.68 475 Localized embrittlement leads to a significant decrease in performance. Comparative Example 3 118 9.2×10¹² 3.55 495 Rough surface, decreased performance
[0096] Table 2 Comparison of appearance and performance after chemical corrosion immersion.
[0097] Sample number Changes in appearance Tensile strength retention Changes in insulation performance Example 1 Basically unchanged Slight decline Basically stable Example 2 No significant changes Stay at the best Stay at the best Example 3 slight changes Maintain good Slight decline Comparative Example 1 Surface white Significant decline Significant decline Comparative Example 2 Localized embrittlement Significant decline Significant decline Comparative Example 3 Surface rough decline decline
[0098] As shown in Table 1, the polyimide films prepared in different embodiments and comparative examples exhibit significant differences in performance indicators such as tensile strength, insulation resistance, dielectric constant, and thermal decomposition temperature. The tensile strengths of Examples 1-3 are 128 MPa, 142 MPa, and 135 MPa, respectively, all significantly higher than the 112 MPa, 108 MPa, and 118 MPa of Comparative Examples 1-3. Among them, Example 2 achieves a tensile strength of 142 MPa, exhibiting the best mechanical properties. This indicates that under moderate synergistic modification conditions, the polyamic acid molecular chain structure is more stable, which is beneficial to improving the film's load-bearing capacity.
[0099] In terms of electrical performance, the insulation resistances of the example samples reached 1.6 × 10¹³ Ω, 2.3 × 10¹³ Ω, and 1.9 × 10¹³ Ω, respectively, all higher than the 7.8 × 10¹² Ω, 6.9 × 10¹² Ω, and 9.2 × 10¹² Ω of the comparative samples. This indicates that synergistic modification and functional regulation of organic small molecules can effectively reduce internal defects and charge conduction paths in the thin film. Among them, Example 2 showed the highest insulation resistance, demonstrating the best electrical insulation performance. Meanwhile, the dielectric constants of the example samples were in the range of 3.30–3.45, generally lower than the 3.55–3.68 of the comparative samples. In particular, Example 2, with a dielectric constant of 3.30, is more suitable for applications in the electronic and electrical fields.
[0100] Analysis of the temperature resistance shows that the thermal decomposition temperatures of Examples 1-3 are 515℃, 535℃, and 525℃, respectively, which are generally higher than the 485℃, 475℃, and 495℃ of the comparative samples. This indicates that the polyimide film formed after imidization of the synergistically modified polyamic acid has higher thermal stability. Among them, Example 2 has the highest thermal decomposition temperature, reaching 535℃, further demonstrating that a reasonable synergistic modification ratio helps to construct a more stable polymer structure.
[0101] As can be seen from the chemical corrosion resistance test results in Table 2, the film appearance of Examples 1-3 remained basically stable after immersion in acids, alkalis, and organic solvents. Example 2 showed no significant appearance change after immersion, and its tensile strength and insulation performance remained the best. Although Examples 1 and 3 showed slight changes, the performance degradation was minimal. In contrast, the comparative samples generally exhibited whitening, localized embrittlement, or surface roughness after immersion, and their tensile strength and insulation performance decreased significantly or substantially, indicating insufficient chemical corrosion resistance.
[0102] In summary, by synergistically modifying the polyamic acid precursor with triethanolamine and piperazine and introducing organic small molecule functional regulators, the mechanical properties, electrical insulation properties, high temperature resistance, and chemical corrosion resistance of polyimide films can be significantly improved. Among them, Example 2 shows the best performance in all performance indicators, fully demonstrating the significant advantages of the technical solution of the present invention in terms of comprehensive performance.
Claims
1. A high-temperature chemically resistant polyimide film, characterized in that, The polyimide film comprises the following raw materials in parts by weight: 85-95 parts of synergistically modified polyamic acid; 0.1-3.0 parts of organic small molecule functional regulator; 50-150 parts of solvent; 0.05-1.0 parts of antioxidant; and 0.05-1.0 parts of stabilizer. The synergistically modified polyamic acid is a polyimide precursor material obtained by synergistic modification of polyamic acid with two organic small molecules, triethanolamine and piperazine. Triethanolamine forms hydrogen bonds with the carboxyl and amide groups in the polyamic acid molecule, while piperazine regulates the conformation and intermolecular force distribution between polyamic acid molecular chains. The synergistic effect of these two compounds improves the structural stability of the polyamic acid system under high temperature and chemical media conditions. The organic small molecule functional regulator is N-methylpyrrolidone, which, while acting as a solvent, participates in the intermolecular regulation process of the synergistically modified polyamic acid system at the molecular scale, thereby further enhancing the high-temperature resistance and chemical corrosion resistance of the obtained polyimide film.
2. The high-temperature chemically resistant polyimide film according to claim 1, characterized in that, The synergistically modified polyamic acid comprises the following raw materials in parts by weight: 88-96 parts of polyamic acid; 0.5-4.0 parts of triethanolamine; 0.1-2.0 parts of piperazine; and 0.05-0.5 parts of 2,6-di-tert-butyl-4-methylphenol. Triphenyl phosphate 0.05-0.5 parts.
3. A high-temperature chemically resistant polyimide film according to claim 1 or 2, characterized in that, The preparation method of the synergistically modified polyamic acid includes the following steps: (1) Add polyamic acid to a solvent and disperse and dissolve it under stirring to obtain a homogeneous polyamic acid solution; (2) Triethanolamine, piperazine, 2,6-di-tert-butyl-4-methylphenol and triphenyl phosphate were added sequentially to the polyamic acid solution, and synergistic modification was carried out under temperature control and stirring conditions to obtain a synergistically modified polyamic acid system. (3) Continue stirring the synergistic modified polyamic acid system until the system is stable to obtain the synergistic modified polyamic acid.
4. The high-temperature chemically resistant polyimide film according to claim 3, characterized in that, The reaction conditions for step (1) are: dissolution at 20-40°C, stirring speed of 50-300 r / min, and dissolution time of 30-120 min; the solvent in step (1) is selected from one or more of N-methylpyrrolidone and dimethylformamide.
5. The high-temperature chemically resistant polyimide film according to claim 3, characterized in that, The reaction conditions for step (2) are as follows: synergistic modification treatment is carried out at 40-70℃, stirring speed is 100-500 r / min, and reaction time is 30-180 min.
6. The high-temperature chemically resistant polyimide film according to claim 3, characterized in that, The reaction conditions for step (3) are to continue stirring at 30-60°C, with a stirring speed of 50-200 r / min and a processing time of 20-120 min.
7. The high-temperature chemically resistant polyimide film according to claim 1, characterized in that, The solvent is a mixture of N-methylpyrrolidone and dimethylformamide in a mass ratio of (5-9):(1-5); the antioxidant is a mixture of 2,6-di-tert-butyl-4-methylphenol and tris[2,4-di-tert-butylphenyl]phosphite in a mass ratio of (1-5):(1-5); and the stabilizer is a mixture of triphenyl phosphate and triphenyl phosphite in a mass ratio of (1-5):(1-5).
8. A method for preparing a high-temperature chemically resistant polyimide film, characterized in that, The preparation method includes the following steps: S1, the synergistically modified polyamic acid system is polymerized under stirring conditions to obtain a synergistically modified polyamic acid system for membrane preparation; S2, the synergistically modified polyamic acid system used for membrane preparation is dried and heat-treated to induce an imidization reaction in the synergistically modified polyamic acid, thereby obtaining a polyimide film; S3, the polyimide film is cut and tested to obtain the finished high-temperature chemically resistant polyimide film.
9. The method for preparing a high-temperature chemically resistant polyimide film according to claim 8, characterized in that, The reaction conditions for step S1 are as follows: the polymerization reaction is carried out in a reactor, the reaction temperature is controlled at 30-68℃, the reaction pressure is controlled at 1-10MPa, and the stirring speed is controlled at 5-300r / min during the reaction.
10. The method for preparing a high-temperature chemically resistant polyimide film according to claim 8, characterized in that, The reaction conditions for step S2 are to dry the synergistically modified polyamic acid system at 80-200°C and then heat it at 200-380°C to complete the imidization reaction; the reaction conditions for step S3 are to cool the obtained polyimide film at 20-40°C and then cut and inspect it at this temperature.