Wide-temperature-range high-moisture-resistance piezoelectric damping material and preparation method thereof

Abstract

The invention relates to a wide-temperature-range high-moisture-resistance piezoelectric damping material and a preparation method thereof.The wide-temperature-range high-moisture-resistance piezoelectric damping material is prepared from, by weight, 80-90 parts of fluorine-containing modified polyimide precursor, 5-12 parts of MXene-CNT heterogeneous conductive filler, 3-8 parts of hydrophobic modified silicon dioxide and 0.3-1.5 parts of cross-linking agent; wherein the fluorine-containing modified polyimide precursor is prepared by copolymerization of 4, 4 '-diaminodiphenyl ether, pyromellitic dianhydride and 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, and the fluorine-containing modified polyimide precursor is prepared by copolymerization of 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane; the hydrophobic modified silicon dioxide is obtained by modifying silicon dioxide through gamma-methacryloxy propyl trimethoxy silane; the cross-linking agent is trimesoyl chloride. The piezoelectric damping material disclosed by the invention is good in low-temperature toughness and has long-term stable moisture-proof performance.

Description

Technical Field

[0001] This invention relates to the field of flexible electronic materials technology, and in particular to a wide-temperature-range high-humidity-voltage-resistant damping material and its preparation method. Background Technology

[0002] Piezoresistive damping materials need to adapt to complex and variable temperature and humidity environments in practical applications, such as extreme low-temperature outdoor conditions or continuously high-humidity medical scenarios. Currently, the most widely used piezoresistive damping material is polyimide-based. Polyimide-based piezoresistive damping materials have the following drawbacks: On the one hand, their high glass transition temperature leads to a significant decrease in elongation at break in cold environments. Under low-temperature conditions, the matrix material is prone to embrittlement, resulting in a significant decrease in piezoresistive sensitivity and an increase in damping coefficient fluctuations. On the other hand, in high-humidity environments, moisture easily penetrates into the internal conductive network of the material, causing filler oxidation or an increase in interfacial resistance. Over time, this leads to problems such as reduced heating efficiency and increased resistance drift.

[0003] To address the aforementioned issues, existing methods typically involve adding plasticizers or applying a hydrophobic coating to the material surface, which can improve low-temperature toughness and enhance moisture resistance. However, while adding plasticizers can effectively lower the glass transition temperature, it often weakens the material's mechanical strength; and the strategy of using a surface hydrophobic coating often results in the coating peeling off due to repeated bending, making it difficult to achieve long-term stable moisture resistance.

[0004] Therefore, there is an urgent need to develop a piezoresistive damping material that combines wide temperature range stability with high moisture resistance, so as to be suitable for long-term reliable applications in extreme environments. Summary of the Invention

[0005] Therefore, it is necessary to provide a wide-temperature-range high-moisture-resistant piezoresistive damping material and its preparation method to address the above-mentioned technical problems. The piezoresistive damping material has good low-temperature toughness and long-term stable moisture resistance.

[0006] In a first aspect, the present invention provides a wide temperature range high moisture resistance damping material, which, by weight, is composed of the following components: 80-90 parts of fluorine-modified polyimide precursor, 5-12 parts of MXene-CNT heterogeneous conductive filler, 3-8 parts of hydrophobic modified silica, and 0.3-1.5 parts of crosslinking agent. The fluorinated modified polyimide precursor is obtained by copolymerization of 4,4'-diaminodiphenyl ether, pyromellitic dianhydride and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; Hydrophobically modified silica is obtained by modifying silica with γ-methacryloyloxypropyltrimethoxysilane; The crosslinking agent is pyromellitic acid chloride.

[0007] Preferably, the fluorinated modified polyimide precursor contains 5-15% 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; The molar ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:1.

[0008] Preferably, the MXene in the MXene-CNT heterogeneous conductive filler is Ti3C2T. x Layers; Ti3C2T x The thickness of the lamellae is 1-5 nm, the diameter of the CNTs is 8-15 nm, and the mass ratio of MXene to CNTs is 1-3:1.

[0009] Preferably, the particle size of the hydrophobically modified silica is 50-200 nm, and the hydrophobic contact angle is ≥110°.

[0010] Preferably, the MXene-CNT heterogeneous conductive filler is 5-12 parts by weight, and the mass ratio of MXene to CNT is 2-2.5:1.

[0011] Preferably, the hydrophobic modified silica has a weight of 5-6 parts and a particle size of 80-150 nm.

[0012] Secondly, the present invention also provides a method for preparing a wide-temperature-range high-humidity-voltage-resistant damping material, which includes the following steps: S1: Add 4,4'-diaminodiphenyl ether, pyromellitic dianhydride and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to N,N-dimethylacetamide, and stir at 40-60℃ for 3-5 h to obtain a fluorinated polyamic acid solution. S2: Add MXene and CNT to N,N-dimethylacetamide and ultrasonically disperse for 40-80 min to obtain a heterogeneous conductive filler dispersion; S3: Add hydrophobic modified silica and crosslinking agent to the heterogeneous conductive filler dispersion, and stir at 50-70℃ for 1-2 hours to obtain a composite filler system; S4: Add the composite filler system to the fluorinated polyamic acid solution and stir at 80-90℃ for 4-6 hours to form a slurry; S5: The slurry is coated onto the substrate and subjected to heat treatments of 100℃ / 1.5h, 200℃ / 1h, 300℃ / 1h, and 380℃ / 0.5h in sequence. After cooling, it is peeled off to obtain a wide temperature range high moisture resistance damping material.

[0013] Preferably, the substrate is aluminum foil with a thickness of 120-200 μm.

[0014] The beneficial effects of this invention are: (1) In this invention, the fluorine atoms of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane in the fluorine-modified polyimide precursor can reduce the intermolecular forces, thereby lowering the glass transition temperature of the wide-temperature-range high-humidity-voltage damping material. Furthermore, the hydroxyl groups of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane can enhance the interfacial bonding force between the fluorine-modified polyimide precursor and the MXene-CNT heterostructure conductive filler, thereby enhancing the mechanical properties of the material. (2) In this invention, hydrophobic modified silica is uniformly dispersed in fluorine-modified polyimide precursor to form a hydrophobic barrier to prevent water penetration, and at the same time, as a crosslinking point, it can improve the mechanical strength of the piezoresistive damping material. Detailed Implementation

[0015] To facilitate understanding of the present invention, a more complete description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0017] The wide-temperature-range high moisture-pressure-resistant damping material of the present invention is composed of the following components by weight: 80-90 parts of fluorine-modified polyimide precursor, 5-12 parts of MXene-CNT heterogeneous conductive filler, 3-8 parts of hydrophobic modified silica, and 0.3-1.5 parts of crosslinking agent. The fluorinated modified polyimide precursor is prepared by copolymerization of 4,4'-diaminodiphenyl ether, pyromellitic dianhydride and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane.

[0018] Specifically, the content of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane in the fluorinated modified polyimide precursor is 5-15%; the molar ratio of 4,4'-diaminodiphenyl ether and pyromellitic dianhydride is 1:1.

[0019] In this embodiment, the MXene in the MXene-CNT heteroconductive filler is Ti3C2T. x Layers; Ti3C2T x The thickness of the lamellae is 1-5 nm, the diameter of the CNTs is 8-15 nm, and the mass ratio of MXene to CNTs is 1-3:1.

[0020] The large hexafluoropropane group in 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane effectively reduces the packing density and interchain forces of the polyimide molecular chains, thereby lowering the glass transition temperature of the matrix and fundamentally solving the embrittlement problem of the material at low temperatures, thus endowing it with wide-temperature-range flexibility. Furthermore, the phenolic hydroxyl groups (-OH) in 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane can act as interfacial compatibilizing groups, forming strong hydrogen bonds or chemical bonds with the oxygen-containing functional groups on the surface of the MXene-CNT heterostructure conductive filler. This greatly enhances the interfacial adhesion between the organic matrix and the inorganic filler, which not only improves the mechanical strength and toughness of the material but also ensures the structural stability and signal transmission reliability of the conductive network under deformation.

[0021] MXene's high conductivity ensures stable conductivity at low temperatures, while the fibrous structure of CNTs (carbon nanotubes) creates a continuous network that synergistically enhances piezoresistive performance over a wide temperature range.

[0022] Hydrophobically modified silica is obtained by modifying silica with γ-methacryloxypropyltrimethoxysilane. The particle size of the hydrophobically modified silica is 50-200 nm, and the hydrophobic contact angle is ≥110°. The crosslinking agent is pyromellitic tricarboxylate chloride.

[0023] Hydrophobic modified silica is uniformly dispersed in the matrix, i.e., the fluorine-modified polyimide precursor, to form a hydrophobic barrier that prevents water penetration and at the same time serves as a crosslinking point to enhance mechanical strength.

[0024] In a preferred embodiment, the MXene-CNT heterogeneous conductive filler comprises 5-12 parts by weight, with an MXene to CNT mass ratio of 2-2.5:1. The hydrophobically modified silica comprises 5-6 parts by weight, with a particle size of 80-150 nm.

[0025] Based on the same invention, this invention also provides a method for preparing a wide-temperature-range high-humidity-pressure-resistant damping material, which includes the following steps: S1: 4,4'-Diaminodiphenyl ether, pyromellitic dianhydride, and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane are added to N,N-dimethylacetamide and stirred at 40-60℃ for 3-5 h to prepare a fluorinated polyamic acid solution. N,N-dimethylacetamide is an aprotic polar solvent.

[0026] S2: Add MXene and CNT to N,N-dimethylacetamide and ultrasonically disperse for 40-80 min to obtain a heterogeneous conductive filler dispersion.

[0027] S3: Add hydrophobic modified silica and crosslinking agent to the heterogeneous conductive filler dispersion, and stir at 50-70℃ for 1-2 hours to obtain a composite filler system.

[0028] S4: Add the composite filler system to the fluorinated polyamic acid solution and stir at 80-90℃ for 4-6 hours to form a slurry.

[0029] S5: The slurry is coated onto the substrate and subjected to heat treatments of 100℃ / 1.5h, 200℃ / 1h, 300℃ / 1h, and 380℃ / 0.5h in sequence. After cooling, it is peeled off to obtain a wide temperature range high moisture resistance damping material.

[0030] Specifically, the substrate is aluminum foil with a thickness of 120-200μm.

[0031] The piezoelectric damping material prepared by the method described in this embodiment is suitable for medical monitoring, outdoor robots, and other scenarios in extreme temperature and humidity environments.

[0032] The following are specific examples.

[0033] Example 1 The wide-temperature-range high-moisture-pressure-resistant damping material of this embodiment is composed of the following components by weight: 85 parts of fluorine-modified polyimide precursor, 8 parts of MXene-CNT heterogeneous conductive filler, 5 parts of hydrophobic modified silica, and 0.8 parts of crosslinking agent. The fluorinated modified polyimide precursor contains 8% 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; Ti3C2T x The thickness of the sheet is 3 nm, the diameter of the CNT is 10 nm, and the mass ratio of MXene to CNT is 2:1. The particle size of the hydrophobic modified silica is 100 nm, and the hydrophobic contact angle is 115°.

[0034] The preparation method of the wide-temperature-range high-moisture-pressure-resistant damping material in this embodiment includes the following steps: S1: 4,4'-diaminodiphenyl ether, pyromellitic dianhydride and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane were added to N,N-dimethylacetamide and stirred at 50°C for 5 h to obtain a fluorinated polyamic acid solution.

[0035] N,N-Dimethylacetamide is an aprotic polar solvent.

[0036] S2: Add MXene and CNT to N,N-dimethylacetamide and ultrasonically disperse for 60 min to obtain a heterogeneous conductive filler dispersion.

[0037] S3: Add hydrophobically modified silica and crosslinking agent to the heterogeneous conductive filler dispersion, and stir at 65°C for 1.5 h to obtain a composite filler system.

[0038] S4: Add the composite filler system to the fluorinated polyamic acid solution and stir at 85°C for 5 hours to form a slurry.

[0039] S5: The slurry is coated onto the substrate and subjected to heat treatments of 100℃ / 1.5h, 200℃ / 1h, 300℃ / 1h, and 380℃ / 0.5h in sequence. After cooling, it is peeled off to obtain a wide temperature range high moisture resistance damping material.

[0040] The performance of the wide-temperature-range high-moisture-voltage-resistant damping material of this embodiment was tested. The test items and test methods are as follows: (1) Piezoresistive sensitivity at -40℃ and 80℃.

[0041] The test was conducted in accordance with GB / T 42191-2023 Performance Test Method for Piezoresistive Pressure Sensitive Devices in Microelectromechanical Systems (MEMS).

[0042] Test procedure: Place the sample in a temperature control chamber and stabilize it to the target temperature (±0.5℃ accuracy); apply static or dynamic load and record the resistance change; sensitivity is defined as the rate of change of resistance under unit load (ΔR / R0).

[0043] (2) Damping coefficients at -40℃ and 80℃.

[0044] The test was conducted according to GB / T 18258-2019 (Test Method for Damping Performance of Damping Materials).

[0045] (3) Elongation at break at -40℃.

[0046] According to the method specified in GB / T 1040.1, the sample was cooled to -40°C using a low-temperature chamber and stretched at a constant rate until it broke. The ratio of the elongation to the initial gauge length was recorded.

[0047] (4) Heating efficiency after 1000h at 90% RH (initial 62%).

[0048] Humidity and heat pretreatment: According to GB / T 2423.3-2016 (constant humidity and heat test), the sample was placed in an environment of 90% RH and 85℃ for 1000 hours.

[0049] Heating efficiency test: The test shall be conducted in accordance with the method specified in GB / T 2423.34-2012 (temperature and humidity cycle test).

[0050] (5) Resistance drift rate.

[0051] Tested according to GB / T 2423.3-2016 (damp heat test).

[0052] Test procedure: Measure the initial resistance R0 at room temperature, and after temperature cycling or damp heat treatment, measure the resistance R1 again. Drift rate = (R1 - R0) / R0 × 100%.

[0053] (6) Contact angle.

[0054] According to GB / T 30693-2014 (static drop method), deionized water is dropped onto the sample surface using a contact angle meter, and the angle between the droplet and the surface is measured using an optical system.

[0055] Test conditions: Droplet volume, 2-5 μL; ambient temperature and humidity, 23±2℃, 50±10%RH.

[0056] (7) Performance retention rate after 1000 bending cycles.

[0057] According to the method specified in ISO 6721 (Dynamic Bending Fatigue), 1000 cycles were performed using a bending testing machine at the target temperature, and the performance retention rate was measured after the test.

[0058] (8) Sensitivity decay rate after 500 thermal cycles.

[0059] According to the method specified in GB / T 2423.22-2012 (Rapid Temperature Change), the temperature was cycled 500 times between -40℃ and 80℃, with each cycle lasting approximately 30 minutes. After cycling, the attenuation rate was measured according to GB / T 42191-2023 (Piezoresistive Sensitivity Test Method), calculated as: (Initial Sensitivity - Sensitivity after Cycles) / Initial Sensitivity × 100%.

[0060] The test results are as follows: Wide temperature range: -40℃, piezoresistive sensitivity 2.1kPa -1 80℃ is 2.3kPa -1 (Change rate 9.5%); Damping coefficient at -40℃ is 0.42, and at 80℃ it is 0.45 (fluctuation 7.1%); Elongation at break at -40℃ is 28%; Moisture resistance: After 1000h at 90% RH, the heating efficiency is 62% (65% initially, 95.4% retention), the resistivity drift is 6.2%, and the contact angle is 108°. Durability: 93% performance retention after 1000 bending cycles, and 4.8% sensitivity decay after 500 thermal cycles.

[0061] Example 2 Other features of this embodiment are the same as those of the previous embodiment, except that: the wide temperature range high moisture resistance damping material of this embodiment is composed of the following components by weight: 82 parts of fluorine-modified polyimide precursor, 10 parts of MXene-CNT heterogeneous conductive filler, 6 parts of hydrophobic modified silica, and 1.2 parts of crosslinking agent. The fluorinated modified polyimide precursor contains 12% 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; Ti3C2T x The thickness of the sheet is 2 nm, the diameter of the CNT is 8 nm, and the mass ratio of MXene to CNT is 3:1. The particle size of the hydrophobic modified silica is 80 nm, and the hydrophobic contact angle is 120°.

[0062] The wide-temperature-range high-moisture-pressure-resistant damping material of this embodiment was subjected to the same performance tests as in Example 1, and the test results are as follows: Wide temperature range: -40℃, piezoresistive sensitivity 2.3kPa -1 80℃ corresponds to 2.5 kPa. -1 (Change rate 8.7%); Damping coefficient 0.45 at -40℃, 0.48 at 80℃ (fluctuation 6.7%); Elongation at break 32% at -40℃; Moisture resistance: After 1000h at 90% RH, the heating efficiency is 64% (66% initially, 97% retention), the resistivity drift is 5.1%, and the contact angle is 112°. Durability: 95% performance retention after 1000 bends, and 3.5% sensitivity decay after 500 thermal cycles.

[0063] Example 3 Other features of this embodiment are the same as those of the previous embodiment, except that: the wide temperature range high moisture resistance damping material of this embodiment is composed of the following components by weight: 88 parts of fluorine-modified polyimide precursor, 6 parts of MXene-CNT heterogeneous conductive filler, 4 parts of hydrophobic modified silica, and 0.5 parts of crosslinking agent. The fluorinated modified polyimide precursor contains 5% 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; Ti3C2T x The thickness of the sheet is 5 nm, the diameter of the CNT is 15 nm, and the mass ratio of MXene to CNT is 1:1. The particle size of the hydrophobic modified silica is 150 nm, and the hydrophobic contact angle is 110°.

[0064] The wide-temperature-range high-moisture-pressure-resistant damping material of this embodiment was subjected to the same performance tests as in Example 1, and the test results are as follows: Wide temperature range: -40℃, piezoresistive sensitivity 1.8kPa -1 80℃ is 1.9kPa -1(Change rate 5.6%); Damping coefficient 0.40 at -40℃, 0.42 at 80℃ (fluctuation 5%); Elongation at break 25% at -40℃; Moisture resistance: After 1000h at 90% RH, the heating efficiency is 59% (62% initially, 95.2% retention), the resistance drift is 7.8%, and the contact angle is 105°. Durability: 92% performance retention after 1000 bends, and 5.0% sensitivity decay after 500 thermal cycles.

[0065] Example 4 Other features of this embodiment are the same as those of the previous embodiment, except that: the wide temperature range high moisture resistance damping material of this embodiment is composed of the following components by weight: 79 parts of fluorine-modified polyimide precursor, 12 parts of MXene-CNT heterogeneous conductive filler, 8 parts of hydrophobic modified silica, and 1.5 parts of crosslinking agent. The fluorinated modified polyimide precursor contains 15% 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; Ti3C2T x The thickness of the sheet is 1 nm, the diameter of the CNT is 12 nm, and the mass ratio of MXene to CNT is 2.5:1. The particle size of the hydrophobic modified silica is 50 nm, and the hydrophobic contact angle is 125°.

[0066] The wide-temperature-range high-moisture-pressure-resistant damping material of this embodiment was subjected to the same performance tests as in Example 1, and the test results are as follows: Wide temperature range: -40℃, piezoresistive sensitivity 2.6kPa -1 80℃ is 2.8kPa -1 (Change rate 7.7%); Damping coefficient 0.52 at -40℃, 0.55 at 80℃ (fluctuation 5.8%); Elongation at break 35% at -40℃; Moisture resistance: After 1000h at 90% RH, the heating efficiency is 68% (70% initially, 97.1% retention), the resistivity drift is 4.3%, and the contact angle is 118°. Durability: 96% performance retention after 1000 bends, and 2.9% sensitivity decay after 500 thermal cycles.

[0067] Example 5 Other features of this embodiment are the same as those of the previous embodiment, except that: the wide temperature range high moisture resistance damping material of this embodiment is composed of the following components by weight: 83 parts of fluorine-modified polyimide precursor, 9 parts of MXene-CNT heterogeneous conductive filler, 5.5 parts of hydrophobic modified silica, and 1 part of crosslinking agent. The fluorinated modified polyimide precursor contains 10% 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; Ti3C2T xThe thickness of the sheet is 4 nm, the diameter of the CNT is 11 nm, and the mass ratio of MXene to CNT is 1.5:1. The particle size of the hydrophobically modified silica is 120 nm, and the hydrophobic contact angle is 117°.

[0068] The wide-temperature-range high-moisture-pressure-resistant damping material of this embodiment was subjected to the same performance tests as in Example 1, and the test results are as follows: Wide temperature range: -40℃, piezoresistive sensitivity 2.2kPa -1 80℃ is 2.4kPa -1 (Change rate 9.1%); Damping coefficient 0.44 at -40℃, 0.46 at 80℃ (fluctuation 4.5%); Elongation at break 30% at -40℃; Moisture resistance: After 1000h at 90% RH, the heating efficiency is 63% (65% initially, 96.9% retention), the resistance drift is 5.7%, and the contact angle is 110°. Durability: 94% performance retention after 1000 bending cycles, and 4.2% sensitivity decay after 500 thermal cycles.

[0069] Example 6 Other features of this embodiment are the same as those of the previous embodiment, except that: the wide temperature range high moisture resistance damping material of this embodiment is composed of the following components by weight: 86 parts of fluorine-modified polyimide precursor, 7 parts of MXene-CNT heterogeneous conductive filler, 3 parts of hydrophobic modified silica, and 0.6 parts of crosslinking agent. The fluorinated modified polyimide precursor contains 7% 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; Ti3C2T x The thickness of the sheet is 3 nm, the diameter of the CNT is 9 nm, and the mass ratio of MXene to CNT is 2:1. The particle size of the hydrophobically modified silica is 180 nm, and the hydrophobic contact angle is 112°.

[0070] The wide-temperature-range high-moisture-pressure-resistant damping material of this embodiment was subjected to the same performance tests as in Example 1, and the test results are as follows: Wide temperature range: -40℃, piezoresistive sensitivity 1.9kPa -1 80℃ corresponds to 2.0 kPa. -1 (Change rate 5.3%); Damping coefficient at -40℃ is 0.41, and at 80℃ it is 0.43 (fluctuation 4.9%); Elongation at break at -40℃ is 27%; Moisture resistance: After 1000h at 90% RH, the heating efficiency is 60% (63% initially, 95.2% retention), the resistivity drift is 7.2%, and the contact angle is 106°. Durability: 93% performance retention after 1000 bending cycles, and 5.1% sensitivity decay after 500 thermal cycles.

[0071] Comparative Example 1 The other features of Comparative Example 1 are basically the same as those of Example 1, except that: the piezoresistive damping material of this example is composed of the following components by weight: 85 parts of pure polyimide precursor, 8 parts of MXene-CNT heterogeneous conductive filler, 5 parts of hydrophobic modified silica, and 0.8 parts of crosslinking agent. The piezoresistive damping material of this embodiment underwent the same performance tests as in Example 1, and the test results are as follows: Performance test: Elongation at break at -40℃ 12%, piezoresistive sensitivity 1.2 kPa⁻¹ (compared to 2.1 kPa at 80℃). -1 The thermal efficiency decreased by 42.9% after 1000 hours at 90% RH (initially 65%, decreasing by 23.1%).

[0072] Comparative Example 2 The other features of Comparative Example 2 are basically the same as those of Example 1, except that: the piezoresistive damping material of this example is composed of the following components by weight: 85 parts of fluorine-modified polyimide precursor, 8 parts of MXene-CNT heterogeneous conductive filler, and 0.8 parts of crosslinking agent; The piezoresistive damping material of this embodiment was subjected to the same performance tests as in Example 1. The test results are as follows: Performance test: After 1000h at 90% RH, the resistance drift rate is 22%, the heating efficiency is 48% (initially 65%, decreased by 26.2%), and the contact angle is 65°.

[0073] A comparison of the test results of Examples 1 to 6 and Comparative Examples 1 to 2 shows that the wide-temperature-range high-moisture-resistance piezoresistive damping material and preparation method of the present invention can significantly improve the material's flexibility, piezoresistive stability, and moisture resistance over a wide temperature range. Within the temperature range of -40℃ to 80℃, the piezoresistive sensitivity of the wide-temperature-range high-moisture-resistance piezoresistive damping material and preparation method of the present invention is 1.8-2.8 kPa. -1 The change rate is ≤10%; the damping coefficient is 0.4-0.55 with fluctuation ≤8%; the elongation at break at -40℃ is ≥25%, far exceeding the 12% of Comparative Example 1; after being placed in a 90% RH environment for 1000 hours, the heat generation efficiency (10V voltage) retention rate is ≥90% (initially 60%-70%), and the resistance drift rate is ≤8%, far less than the 22% of Comparative Example 2; the hydrophobic contact angle is maintained at ≥100°; after 1000 bending cycles, the performance retention rate is ≥92%, and the hydrophobic layer does not fall off; after 500 thermal cycles (-40℃ to 80℃), the piezoresistive sensitivity decay is ≤5.1%.

[0074] The wide-temperature-range high-humidity-resistant damping material of the present invention is suitable for environments with temperatures ranging from -40°C to 80°C and relative humidity ≤90%.

[0075] Specifically, the introduction of fluorinated modified polyimide precursors increases the elongation at break of the material to over 25% at -40°C, effectively mitigating the low-temperature embrittlement problem. The addition of hydrophobic modified silica controls the resistivity drift rate to below 8% under high humidity conditions, significantly enhancing the material's moisture resistance stability. Furthermore, the material maintains high sensitivity and performance retention even after repeated bending and thermal cycling, demonstrating excellent durability and environmental adaptability.

[0076] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A wide-temperature-range high-moisture-pressure-resistant damping material, characterized in that, By weight, it consists of the following components: 80-90 parts of fluorinated modified polyimide precursor, 5-12 parts of MXene-CNT heterogeneous conductive filler, 3-8 parts of hydrophobic modified silica, and 0.3-1.5 parts of crosslinking agent. The fluorinated modified polyimide precursor is obtained by copolymerization of 4,4'-diaminodiphenyl ether, pyromellitic dianhydride and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; The hydrophobically modified silica is obtained by modifying silica with γ-methacryloxypropyltrimethoxysilane; The crosslinking agent is pyromellitic acid chloride.

2. The wide-temperature-range high-moisture-pressure-resistant damping material according to claim 1, characterized in that, The fluorinated modified polyimide precursor contains 5-15% 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; The molar ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:

1.

3. The wide-temperature-range high-moisture-pressure-resistant damping material according to claim 2, characterized in that, The MXene-CNT hetero-conductive filler has MXene as Ti3C2T x Platelets; The Ti3C2T x The thickness of the lamellae is 1-5 nm, the diameter of the CNTs is 8-15 nm, and the mass ratio of MXene to CNTs is 1-3:

1.

4. The wide-temperature-range high-moisture-pressure-resistant damping material according to claim 3, characterized in that, The hydrophobic modified silica has a particle size of 50-200 nm and a hydrophobic contact angle ≥110°.

5. The wide-temperature-range high-moisture-pressure-resistant damping material according to claim 3, characterized in that, The MXene-CNT heterogeneous conductive filler is 5-12 parts by weight, and the mass ratio of MXene to CNT is 2-2.5:

1.

6. The wide-temperature-range high-moisture-pressure-resistant damping material according to claim 4, characterized in that, The hydrophobic modified silica has a weight of 5-6 parts and a particle size of 80-150 nm.

7. A method for preparing a wide-temperature-range high-moisture-voltage-resistant damping material, used to prepare the wide-temperature-range high-moisture-voltage-resistant damping material as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Add 4,4'-diaminodiphenyl ether, pyromellitic dianhydride and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to N,N-dimethylacetamide, and stir at 40-60℃ for 3-5 h to obtain a fluorinated polyamic acid solution. S2: Add MXene and CNT to N,N-dimethylacetamide and ultrasonically disperse for 40-80 min to obtain a heterogeneous conductive filler dispersion; S3: Add hydrophobic modified silica and crosslinking agent to the heterogeneous conductive filler dispersion, and stir at 50-70℃ for 1-2 hours to obtain a composite filler system; S4: Add the composite filler system to the fluorinated polyamic acid solution and stir at 80-90℃ for 4-6 hours to form a slurry; S5: The slurry is coated onto the substrate and subjected to heat treatments of 100℃ / 1.5h, 200℃ / 1h, 300℃ / 1h, and 380℃ / 0.5h in sequence. After cooling, it is peeled off to obtain a wide temperature range high moisture resistance damping material.

8. The method for preparing the wide-temperature-range high-moisture-pressure-resistant damping material according to claim 7, characterized in that, The substrate is an aluminum foil with a thickness of 120-200 μm.