A fatigue-resistant fluororubber with extremely low crack propagation rate, its preparation method and uses

Abstract

This invention provides a fatigue-resistant fluororubber with extremely low crack propagation rate, its preparation method, and its applications, belonging to the field of chemical materials. The fatigue-resistant fluororubber is prepared from raw materials comprising the following weight components: 100 parts fluororubber raw rubber, 0-30 parts zero-dimensional filler, 0.15-1.35 parts one-dimensional filler, 12-18 parts two-dimensional filler, 1-5 parts vulcanizing agent, 0.1-1 parts vulcanization accelerator, 2-10 parts acid scavenger, and 0-1 parts processing aid; the one-dimensional filler is carbon nanotubes surface-modified with a fluorosilane coupling agent. This invention uses a composite of two-dimensional and one-dimensional fillers as reinforcing fillers, significantly improving the crack propagation resistance of fluororubber and effectively enhancing its fatigue service capability; simultaneously, it maintains good mechanical properties, meeting the comprehensive requirements of strength, flexibility, and fatigue resistance for high-end core components such as dynamic and static seals, thus expanding the application scenarios of fluororubber in the field of high-end equipment.

Description

Technical Field

[0001] This invention belongs to the field of chemical materials, specifically relating to a fatigue-resistant fluororubber with extremely low crack propagation rate, its preparation method, and its uses. Background Technology

[0002] Fluororubber is a special type of high-molecular elastic material in which fluorine atoms are bonded to carbon atoms in the main chain or side chain. The strong electronegativity of fluorine atoms and the high bond energy CF bond structure endow it with excellent resistance to high and low temperatures, mineral oils, organic solvents, acid and alkali corrosion, atmospheric aging, and ozone aging. It also possesses good airtightness and insulation properties. Due to these unique advantages, fluororubber has become an indispensable sealing material in the high-end equipment field, and is widely used in key areas such as aerospace, high-end automotive industry, petrochemicals, hydraulic transmission, and precision instruments. It is mainly used to manufacture various dynamic and static seals, diaphragms, shock absorbers, and other core components, and is a key consumable material to ensure the long-term, stable, and safe operation of high-end equipment.

[0003] In actual engineering service scenarios, the vast majority of fluororubber sealing components are not in a static, stationary state, but rather are subjected to complex, periodic, dynamic, alternating loads over a long period. For example, the high-frequency vibrations during the operation of aero engines, the reciprocating impacts of automotive power systems, the cyclic pressure fluctuations of hydraulic and pneumatic systems, and the high-frequency flexural motion of diaphragm pumps and reciprocating machinery all subject fluororubber materials to alternating stresses of tension, compression, bending, and shearing. Long-term, repeated dynamic loads disrupt the stable structure of the polymer chains within the rubber, leading to molecular chain slippage, breakage, and the accumulation of interface defects. This causes microscopic pores and microcracks to gradually form within the material. As the service life continues to increase, these microcracks continuously initiate, converge, and expand, gradually evolving into macroscopic cracks. Ultimately, this results in cracking, deformation, leakage, and even overall fracture failure of the seals, significantly shortening equipment lifespan and potentially causing equipment malfunctions, safety hazards, and economic losses. Relevant engineering tests and academic research data show that fluororubber seals prepared with conventional formulas have poor fatigue resistance under typical dynamic conditions such as high-frequency flexure and alternating loads. Their cumulative flexure service life is only about 10,000 cycles before significant crack damage and performance degradation occur, which cannot meet the long-term stable service requirements of high-end equipment.

[0004] To address the issues of dynamic fatigue cracking and rapid crack propagation in fluororubber, numerous modification studies have been conducted within the industry. These studies primarily focus on filler functional modification (such as functionalizing filler surfaces with grafted antioxidants), optimization of vulcanization and acid-absorbing system formulations, and nano-reinforced filler filling (such as carbon nanotubes). These approaches can, to some extent, slightly improve the basic flexural fatigue resistance of fluororubber. However, filler functional modification methods suffer from complex processes, only slightly delaying the breakage of rubber molecular chains and failing to fundamentally inhibit the initiation and propagation of microcracks. Optimization of vulcanization and acid-absorbing system formulations offers limited performance improvements and is difficult to adapt to the harsh dynamic service conditions of high-frequency, long-term operation. High-filler nano-reinforced systems are prone to filler agglomeration, causing stress concentration within the matrix and inducing crack defects, thus failing to effectively control the crack propagation rate.

[0005] Currently, research on the suppression mechanisms of microcrack initiation and propagation in fluororubber under alternating loads is still insufficient both domestically and internationally. Mature modification schemes and processes that can effectively reduce crack propagation rates and improve dynamic fatigue life are lacking. Therefore, the targeted development of a fluororubber material with low crack propagation rates and high dynamic fatigue resistance has significant engineering application value for improving the reliability and service life of various core components such as fluororubber seals, diaphragms, and vibration damping parts in high-end equipment. Summary of the Invention

[0006] The purpose of this invention is to provide a fatigue-resistant fluororubber with extremely low crack propagation rate, its preparation method, and its uses.

[0007] This invention provides a fatigue-resistant fluororubber, which is made from raw materials comprising the following weight components: 100 parts of fluororubber raw rubber, 0-30 parts of zero-dimensional filler, 0.15-1.35 parts of one-dimensional filler, 12-18 parts of two-dimensional filler, 1-5 parts of vulcanizing agent, 0.1-1 parts of vulcanization accelerator, 2-10 parts of acid scavenger, and 0-1 parts of processing aid; wherein the one-dimensional filler is carbon nanotubes surface-modified with a fluorosilane coupling agent.

[0008] The zero-dimensional packing, one-dimensional packing, and two-dimensional packing are all reinforcing packings; among them, the zero-dimensional packing is a granular packing with no obvious aspect ratio in any direction; the one-dimensional packing is a packing with an obvious aspect ratio in only one dimension, and is linear, tubular, or rod-shaped; the two-dimensional packing is a packing that forms an extended planar structure in two dimensions, and is lamellar or sheet-like.

[0009] Furthermore, it is made from raw materials comprising the following weight components: 100 parts of fluororubber raw rubber, 0.5 to 1.25 parts of one-dimensional filler, 12.5 to 16.25 parts of two-dimensional filler, 1.8 parts of vulcanizing agent, 0.4 parts of vulcanization accelerator, 9 parts of acid absorber, and 1 part of processing aid.

[0010] Furthermore, it is made from raw materials comprising the following weight components: 100 parts of fluororubber raw rubber, 1.25 parts of one-dimensional filler, 12.5 parts of two-dimensional filler, 1.8 parts of vulcanizing agent, 0.4 parts of vulcanization accelerator, 9 parts of acid absorber, and 1 part of processing aid.

[0011] Further, the fluororubber raw rubber is selected from at least one of vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, and fluoroether rubber; the zero-dimensional filler is selected from at least one of carbon black, silica, carbon microspheres, and nano zinc oxide; the fluorinated silane coupling agent is selected from at least one of C3-C12 perfluoroalkyltrimethoxysilane and C3-C12 perfluoroalkyltriethoxysilane; the two-dimensional filler is selected from at least one of graphite, graphene, boron nitride, and montmorillonite; and the vulcanizing agent is selected from bisphenol A. F, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, dicumyl peroxide, bisphenol A, bisphenol S; the vulcanization accelerator is selected from at least one of benzyltriphenylphosphine chloride, tetraphenylphosphonium chloride, tetrabutylphosphonium bromide, ethyltriphenylphosphonium bromide, butyltriphenylphosphonium chloride; the acid scavenger is selected from at least one of magnesium oxide, calcium hydroxide, calcium oxide, zinc oxide; the processing aid is selected from at least one of palm wax, paraffin wax, microcrystalline wax, polyethylene wax, polypropylene wax, zinc stearate, calcium stearate.

[0012] Further, the fluorinated silane coupling agent is selected from at least one of perfluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, perfluorooctyltrimethoxysilane, and perfluorooctyltriethoxysilane. The acid scavenger is a mixture of magnesium oxide and calcium hydroxide, wherein the mass ratio of magnesium oxide to calcium hydroxide is 1:2.

[0013] Further, the preparation method of the carbon nanotubes modified by the fluorinated silane coupling agent includes the following steps: (1) dispersing the carbon nanotubes in water or organic solvent solution, adding an oxidant, reacting, collecting the solid product and drying it to obtain hydroxyl-containing carbon nanotubes; (2) adding a fluorinated silane coupling agent to a mixed solution of organic solvent and water, hydrolyzing it to obtain a fluorinated silane hydrolysate; (3) adding the hydroxyl-containing carbon nanotubes to the fluorinated silane hydrolysate, reacting, centrifuging, washing, and drying it to obtain the final product.

[0014] Further, the organic solvent is selected from at least one of ethanol, methanol, isopropanol, acetone, and ethylene glycol; the oxidant is selected from at least one of hydrogen peroxide, peracetic acid, tert-butyl hydroperoxide, and hydrogen peroxide urea; the mass of the fluorinated silane coupling agent is 8% to 40% of the mass of the carbon nanotubes; the ratio of the oxidant to the carbon nanotubes is 1 g: (50 to 100) mL; in step (1), the reaction time is 4 to 8 h; in step (2), the volume ratio of the organic solvent to water is 95:5; the hydrolysis time is 30 to 60 min; in step (3), the reaction temperature is 50 to 80 °C, and the time is 12 to 24 h.

[0015] Furthermore, the mass of the fluorinated silane coupling agent is 32% of the mass of the carbon nanotubes.

[0016] Furthermore, the mass fraction of the fluorinated silane coupling agent in the mixed solution of anhydrous ethanol and water is 1~5 wt% (relative to the mass fraction of the mixed solution).

[0017] The present invention also provides a method for preparing fatigue-resistant fluororubber, comprising the following steps: plasticizing raw fluororubber until uniform; then adding zero-dimensional filler, two-dimensional filler, vulcanizing agent, vulcanization accelerator, acid absorber and processing aid and mixing until uniform; then adding one-dimensional filler and mixing until uniform; subsequently re-mixing to obtain compound; finally, subjecting the compound to first-stage vulcanization and second-stage vulcanization to obtain the final product.

[0018] Furthermore, the addition of one-dimensional filler involves dividing the one-dimensional filler into two equal parts and adding them in two separate steps; the conditions for the first-stage vulcanization are: temperature 160~180℃, pressure 10~15MPa, and time 10~30 minutes; the conditions for the second-stage vulcanization are: temperature 200~230℃ and time 4~24 hours.

[0019] The present invention also provides the use of fatigue-resistant fluororubber in the preparation of dynamic seals, static seals, diaphragms or shock absorbers.

[0020] This invention uses a compound of two-dimensional fillers and fluorinated silane-modified carbon nanotubes as reinforcing fillers, which significantly improves the crack propagation resistance of fluororubber and effectively enhances its fatigue service capability. At the same time, it maintains good mechanical properties, meeting the comprehensive requirements of high-end core components such as dynamic and static seals for strength, flexibility and fatigue resistance, thus expanding the application scenarios of fluororubber in the field of high-end equipment. Experiments have shown that the material constant of fluororubber prepared with 12.5–16.25 parts graphite and 0.5–1.25 parts perfluorosilane-modified carbon nanotubes as reinforcing fillers is 6–16 orders of magnitude lower than that of fluororubber prepared with single graphite (17 parts) and single carbon black (30 parts) as reinforcing fillers, as well as fluororubber prepared without reinforcing fillers. Simultaneously, it exhibits good mechanical properties, with a hardness of 70–75.3 Shore A, a tensile strength of 9.07–12.66 MPa, and an elongation at break of 235.11–288.26%. Among these, the fluororubber prepared with 12.5 parts graphite and 1.25 parts modified carbon nanotubes has the lowest material constant, at 8.7459 × 10⁻⁶. -41 It exhibits optimal fatigue resistance. However, excessive addition of modified carbon nanotubes (11.25 parts graphite and 1.5 parts modified carbon nanotubes) significantly degrades the fatigue resistance of fluororubber, increasing the material constant to 3.5195 × 10⁻⁶. -26 The combination of unmodified carbon nanotubes and graphite also cannot effectively improve the fatigue resistance of fluororubber.

[0021] This invention provides a mature modification scheme and process for effectively reducing the crack propagation rate of fluororubber and significantly improving its dynamic fatigue life. It clarifies the optimal ratio window for graphite-modified carbon nanotube composites, and overcomes the technical bottlenecks of poor dispersion of carbon nanotubes in fluororubber, weak interfacial bonding, and poor fatigue resistance of fluororubber. This invention has significant engineering application value for improving the reliability and service life of various fluororubber seals, diaphragms, shock absorbers, and other core components of high-end equipment.

[0022] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0023] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following embodiments. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0024] Figure 1 This is a graph showing the fitting results of the fatigue crack propagation rate test in Example 4. Detailed Implementation

[0025] The raw materials and equipment used in this invention are all known products, obtained by purchasing commercially available products.

[0026] Fluororubber raw rubber was purchased from Shanghai Huayi Sanai Fu New Materials Co., Ltd., model FE2603, which is a copolymer of vinylidene fluoride and hexafluoropropylene, with a Mooney viscosity of 48 (ML 1+10, 121℃); magnesium oxide was purchased from Kyowa Chemical Industry Co., Ltd.; calcium hydroxide was purchased from Inoue Lime Industry Co., Ltd., model NICC5000; benzyltriphenylphosphine chloride (BPP).

[0027] Example 1: Preparation of fluororubber 1.1 Preparation of modified carbon nanotubes (1) Weigh 100g of carbon nanotubes (CNTs) and add them to deionized water or ethanol. Disperse them by sonication for 30 minutes to form a uniform suspension. Then slowly add 30% (mass fraction) hydrogen peroxide solution. The ratio of carbon nanotubes to hydrogen peroxide is 1:100 (g:mL). React at a constant temperature for 4 hours under magnetic stirring. After the reaction is complete, cool to room temperature, dilute with deionized water, and place the solid product in a vacuum drying oven. Dry at 70℃ for 12 hours to obtain carbon nanotubes containing hydroxyl groups (CNT-OH). (2) Add 4 wt% fluorosilane (relative to the mass fraction of the mixed solution) dropwise to 1000 mL of a mixture of anhydrous ethanol and water (volume ratio: ethanol:water = 95:5), stir at room temperature for 60 minutes to obtain silane hydrolysate; (3) Add CNT-OH to the silane hydrolysate, stir evenly, heat to 70°C, react for 24 hours, centrifuge at 8000 rpm for 15 minutes, discard the supernatant, wash repeatedly with anhydrous ethanol and deionized water, centrifuge, place the washed solid in a vacuum drying oven, dry at 70°C for 12 hours to obtain perfluorosilane modified carbon nanotubes.

[0028] 1.2 Preparation of fluororubber Formula: As shown in Table 1; Prepare according to the formula as follows: (1) Plasticizing raw rubber: Plasticize the fluororubber raw rubber through a two-roll mill 2-3 times, adjust the roller gap to 0.5-1mm, and control the roller temperature at 40-50℃ to make the raw rubber plasticize evenly. (2) First stage of mixing: Put the plasticized rubber into the internal mixer, add bisphenol AF, BPP, magnesium oxide, NICC5000, palm wax and graphite, mix evenly, and the temperature is ≤80℃; (3) Two-stage mixing: First, add half of the modified carbon nanotubes and mix evenly; then add the remaining modified carbon nanotubes and mix evenly. (4) Re-mixing: Cool the mixed rubber obtained by mixing for 24 hours, put it back into the open mill or internal mixer, and mix it evenly at 40℃~60℃ to prevent scorching; (5) First stage vulcanization: After the final compound rubber is sheeted out and left to stand for 24 hours, it is placed in a mold and vulcanized on a flat vulcanizing machine. The vulcanization conditions are: temperature 170℃, pressure 15MPa, time 10 minutes. (6) Second stage vulcanization: The product after the first stage vulcanization is placed in a hot air oven for second stage vulcanization. The vulcanization conditions are: temperature 220℃, time 24 hours.

[0029] Example 2: Preparation of fluororubber 2.1 Preparation of modified carbon nanotubes: Same as in Example 1; 2.2 Preparation of fluororubber: Prepared according to the formulation shown in Table 1 and the method of Example 1.

[0030] Example 3: Preparation of fluororubber 3.1 Preparation of modified carbon nanotubes: Same as in Example 1; 3.2 Preparation of fluororubber: Prepared according to the formulation shown in Table 1 and the method of Example 1.

[0031] Example 4: Preparation of fluororubber 4.1 Preparation of modified carbon nanotubes: Same as in Example 1; 4.2 Preparation of fluororubber: Prepared according to the formulation shown in Table 1 and the method of Example 1.

[0032] Comparative Example 1: Preparation of Fluororubber Prepared according to the formulation shown in Table 1, referring to the method of Example 1; the difference in preparation method is: There is no step (3) two-stage mixing.

[0033] Comparative Example 2: Preparation of Fluororubber Prepared according to the formulation shown in Table 1, referring to the method of Example 1; the difference in preparation method is: Step (2) is: First stage of mixing: Put the plasticized rubber into the internal mixer, add magnesium oxide, NICC5000, palm wax and carbon black, mix evenly, and the temperature is ≤80℃; There is no step (3) two-stage mixing.

[0034] Comparative Example 3: Preparation of Fluororubber The preparation was carried out according to the formulation shown in Table 1, following the method of Example 1; the difference in the preparation method was that the modified carbon nanotubes were replaced with unmodified carbon nanotubes.

[0035] Comparative Example 4: Preparation of Fluororubber Prepared according to the formulation shown in Table 1 and the method of Example 1.

[0036] Comparative Example 5: Preparation of Fluororubber The formulation shown in Table 1 was prepared according to the method of Example 1; the difference in the preparation method is that step (3) two-stage mixing was not performed.

[0037] Table 1. Formulations (parts by weight) of Examples 1-4 and Comparative Examples 1-5 Experimental Examples and Performance Testing of Fluororubber 1. Experimental Methods Fatigue crack propagation rate testing: Following the ASTM D813-20 standard method, the crack propagation rate was tested at room temperature (23±2℃) and a loading frequency of 10Hz using a constant strain energy release rate mode. The crack length *a* and the number of cycles *N* were recorded, and the fitting formula was: da / dN=A T α Where da / dN is the crack propagation rate (μm / cycle); A is a material constant, related to the fatigue performance of the material. Experimental measurements show that the larger A is, the faster the crack propagation rate; T α This refers to the temperature-related factors.

[0038] The hardness and mechanical properties (tensile strength, elongation at break, and tensile strength) of fluororubber were tested using the national standard methods GB / T531.1-2008 and GB / T 528-2009.

[0039] 2. Experimental Results As shown in Table 2, compared with Comparative Examples 1, 2, and 5, the material constants of the fluororubbers prepared by adding graphite and modified carbon nanotube composite reinforcing fillers in Examples 1-4 were reduced by 6-16 orders of magnitude. This indicates that the composite of graphite and modified carbon nanotubes effectively improves the crack propagation resistance of fluororubber and significantly enhances the fatigue service capability of the material. At the same time, the prepared fluororubber also has good mechanical properties, with a hardness of 70-75.3 Shore A, a tensile strength of 9.07-12.66 MPa, and an elongation at break of 235.11%-288.26%, which meets the comprehensive requirements of dynamic seals for strength, flexibility, and fatigue resistance.

[0040] Among them, the fluororubber prepared by adding 12.5 parts of graphite and 1.25 parts of modified carbon nanotubes in Example 4 had the lowest material constant, which was 8.7459 × 10⁻⁶. -41 (like Figure 1The fitting results shown indicate that the material constant of the fluororubber prepared by adding only 17 parts of graphite in Comparative Example 1 was reduced by 16 orders of magnitude, the material constant of the fluororubber prepared by adding only 30 parts of carbon black N990 in Comparative Example 2 was reduced by 12 orders of magnitude, and the material constant of the fluororubber prepared by not adding reinforcing filler in Comparative Example 5 was reduced by 13 orders of magnitude.

[0041] However, compared with the fluororubber prepared by adding 11.25 parts of graphite and 1.5 parts of modified carbon nanotubes in Comparative Example 4, the material constant of the fluororubber prepared in Comparative Example 4 increased by 15 orders of magnitude. This indicates that the addition of too much modified carbon nanotubes and the imbalance in the mass ratio of graphite and modified carbon nanotubes will significantly degrade the fatigue resistance of the fluororubber.

[0042] Compared with the fluororubber prepared by adding graphite and unmodified carbon nanotubes in Comparative Example 3, the material constant of the fluororubber prepared in Comparative Example 4 increased by 11 orders of magnitude. This indicates that modified carbon nanotubes play a key role in improving the fatigue resistance of fluororubber, and the combination of unmodified carbon nanotubes and graphite cannot effectively improve the fatigue resistance of fluororubber.

[0043] Table 2 shows the properties of the fluororubbers prepared in Examples 1-4 and Comparative Examples 1-5. In summary, this invention uses a composite of graphite and perfluorosilane-modified carbon nanotubes as a reinforcing filler, significantly improving the crack propagation resistance of fluororubber and effectively enhancing its fatigue resistance. Simultaneously, it maintains good mechanical properties, meeting the comprehensive requirements of dynamic seals for strength, flexibility, and fatigue resistance. Experiments show that the material constant of fluororubber prepared with 12.5–16.25 parts graphite and 0.5–1.25 parts perfluorosilane-modified carbon nanotubes as reinforcing fillers is 6–16 orders of magnitude lower than that of fluororubber prepared with single graphite (17 parts) and single carbon black (30 parts) as reinforcing fillers, and fluororubber prepared without any reinforcing fillers. The fluororubber prepared with 12.5 parts graphite and 1.25 parts modified carbon nanotubes has the lowest material constant, 8.7459 × 10⁻⁶. -41 It exhibits optimal fatigue resistance. However, excessive addition of modified carbon nanotubes (11.25 parts graphite and 1.5 parts modified carbon nanotubes) significantly degrades the fatigue resistance of fluororubber, increasing the material constant to 3.5195 × 10⁻⁶. -26 The combination of unmodified carbon nanotubes and graphite also cannot effectively improve the fatigue resistance of fluororubber.

Claims

1. A fatigue-resistant fluororubber, characterized in that, It is made from raw materials comprising the following weight components: 100 parts of fluororubber raw rubber, 0-30 parts of zero-dimensional filler, 0.15-1.35 parts of one-dimensional filler, 12-18 parts of two-dimensional filler, 1-5 parts of vulcanizing agent, 0.1-1 parts of vulcanization accelerator, 2-10 parts of acid scavenger, and 0-1 parts of processing aid; wherein the one-dimensional filler is carbon nanotubes surface-modified with a fluorosilane coupling agent.

2. The fatigue-resistant fluororubber according to claim 1, characterized in that, It is made from raw materials comprising the following weight components: 100 parts of fluororubber raw rubber, 0.5 to 1.25 parts of one-dimensional filler, 12.5 to 16.25 parts of two-dimensional filler, 1.8 parts of vulcanizing agent, 0.4 parts of vulcanization accelerator, 9 parts of acid absorber, and 1 part of processing aid.

3. The fatigue-resistant fluororubber according to claim 2, characterized in that, It is made from raw materials comprising the following weight components: 100 parts of fluororubber raw rubber, 1.25 parts of one-dimensional filler, 12.5 parts of two-dimensional filler, 1.8 parts of vulcanizing agent, 0.4 parts of vulcanization accelerator, 9 parts of acid absorber, and 1 part of processing aid.

4. The fatigue-resistant fluororubber according to any one of claims 1 to 3, characterized in that, The fluororubber raw material is selected from at least one of vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, and fluoroether rubber; the zero-dimensional filler is selected from at least one of carbon black, silica, carbon microspheres, and nano zinc oxide; the fluorinated silane coupling agent is selected from at least one of C3-C12 perfluoroalkyltrimethoxysilane and C3-C12 perfluoroalkyltriethoxysilane; the two-dimensional filler is selected from at least one of graphite, graphene, boron nitride, and montmorillonite; the vulcanizing agent is selected from bisphenol AF, The following are selected from the following: 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, dicumyl peroxide, bisphenol A, and bisphenol S; the vulcanization accelerator is selected from at least one of benzyltriphenylphosphine chloride, tetraphenylphosphonium chloride, tetrabutylphosphonium bromide, ethyltriphenylphosphonium bromide, and butyltriphenylphosphonium chloride; the acid scavenger is selected from at least one of magnesium oxide, calcium hydroxide, calcium oxide, and zinc oxide; the processing aid is selected from at least one of palm wax, paraffin wax, microcrystalline wax, polyethylene wax, polypropylene wax, zinc stearate, and calcium stearate.

5. The fatigue-resistant fluororubber according to claim 4, characterized in that, The fluorinated silane coupling agent is selected from at least one of perfluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, perfluorooctyltrimethoxysilane, and perfluorooctyltriethoxysilane; the acid scavenger is a mixture of magnesium oxide and calcium hydroxide, wherein the mass ratio of magnesium oxide to calcium hydroxide is 1:

2.

6. The fatigue-resistant fluororubber according to any one of claims 1 to 3, characterized in that, The preparation method of carbon nanotubes modified by fluorinated silane coupling agent includes the following steps: (1) dispersing carbon nanotubes in water or organic solvent solution, adding oxidant, reacting, collecting solid product and drying to obtain carbon nanotubes containing hydroxyl groups; (2) adding fluorinated silane coupling agent to a mixed solution of organic solvent and water, hydrolyzing to obtain fluorinated silane hydrolysate; (3) adding hydroxyl-containing carbon nanotubes to fluorinated silane hydrolysate, reacting, centrifuging, washing, and drying to obtain the final product.

7. The fatigue-resistant fluororubber according to claim 6, characterized in that, The organic solvent is selected from at least one of ethanol, methanol, isopropanol, acetone, and ethylene glycol; the oxidant is selected from at least one of hydrogen peroxide, peracetic acid, tert-butyl hydroperoxide, and hydrogen peroxide urea; the mass of the fluorinated silane coupling agent is 8% to 40% of the mass of the carbon nanotubes; the ratio of the oxidant to the carbon nanotubes is 1 g:(50 to 100) mL; in step (1), the reaction time is 4 to 8 h; in step (2), the volume ratio of the organic solvent to water is 95:5, and the hydrolysis time is 30 to 60 min; in step (3), the reaction temperature is 50 to 80 °C, and the time is 12 to 24 h.

8. The method for preparing fatigue-resistant fluororubber according to any one of claims 1 to 7, characterized in that, Includes the following steps: The raw fluororubber is plasticized evenly; then zero-dimensional filler, two-dimensional filler, vulcanizing agent, vulcanization accelerator, acid absorber, and processing aid are added and mixed evenly; then one-dimensional filler is added and mixed evenly; then re-mixed to obtain the compound; finally, the compound is subjected to first-stage vulcanization and second-stage vulcanization to obtain the final product.

9. The preparation method according to claim 8, characterized in that, The addition of one-dimensional filler involves dividing the one-dimensional filler into two equal parts and adding them in two separate steps; the conditions for the first-stage vulcanization are: temperature 160~180℃, pressure 10~15MPa, and time 10~30 minutes; the conditions for the second-stage vulcanization are: temperature 200~230℃ and time 4~24 hours.

10. Use of the fatigue-resistant fluororubber according to any one of claims 1 to 7 in the preparation of dynamic seals, static seals, diaphragms or shock absorbers.

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