A porous sealing gasket with a high elastic recovery rate and its preparation method

Abstract

The present invention discloses a preparation method of a porous sealing gasket with a high elastic recovery rate, which comprises the following steps S1: dissolving fluoroolefin, 1,1,1,3,3,3-hexafluoro-2-propyleneimine and an initiator in a solvent respectively; S2: inputting them into a three-channel microreactor and carrying out low-temperature polymerization to generate a fluorinated copolymer; S3: introducing fluorinated graphene grafted with a RAFT chain transfer agent on the surface at the outlet of the polymerization reaction and applying a shear rate through a conical channel; S4: compounding the product with natural rubber to form a composite colloid and injecting it into a mold, carrying out dynamic vulcanization and simultaneously introducing a supercritical CO2 foaming agent; S5: after demolding, carrying out plasma surface fluorination treatment and hot pressing and shaping in sequence to obtain the porous sealing gasket. The preparation method of the present invention not only realizes the high elastic recovery rate of the sealing gasket, but also has excellent chemical resistance and high temperature resistance, and can meet the long-term durability and stability requirements of application fields such as aerospace and automobiles.

Description

Technical Field

[0001] The present invention relates to the technical field of sealing gaskets, and particularly to a porous sealing gasket with a high elastic recovery rate and a preparation method thereof. Background Art

[0002] In the field of sealing gaskets, traditional materials such as natural rubber, nitrile rubber, and silicone rubber are widely used. However, these materials have many limitations in practical applications. For example, although natural rubber has good elastic recovery ability, its chemical resistance and high-temperature resistance are poor, making it difficult to meet the usage requirements under complex working conditions. Nitrile rubber has good oil resistance, but its elastic recovery ability is insufficient, and it is prone to permanent deformation during repeated compression and release processes. Silicone rubber performs well in high and low temperature resistance, but its mechanical strength and elastic recovery ability still need to be improved.

[0003] In addition, traditional sealing gaskets have non-uniformity in their microstructures, resulting in stress concentration, which further affects the overall performance of the materials. In terms of processing technology, traditional preparation methods usually require multiple complex processes, with low production efficiency and high costs. These problems limit the use of sealing gaskets in high-performance and high-reliability applications, especially in fields such as aerospace, automotive industry, and chemical equipment, where higher requirements are put forward for the comprehensive performance of sealing materials. Therefore, developing a sealing gasket material that can simultaneously meet high elastic recovery ability, chemical resistance, and high-temperature resistance has become an important research direction. Summary of the Invention

[0004] In view of the above deficiencies of the prior art, the present invention provides a preparation method for a porous sealing gasket with a high elastic recovery rate to solve the deficiencies of traditional sealing gaskets in terms of elastic recovery ability, chemical resistance, and high-temperature resistance, and at the same time optimize its microstructure and processing technology, thereby improving its comprehensive performance and meeting the requirements of long-term durability and stability.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A preparation method for a porous sealing gasket with a high elastic recovery rate, the preparation method comprising the following steps:

[0007] S1: Dissolve fluoroolefin, 1,1,1,3,3,3-hexafluoro-2-propenimine, and an initiator in a solvent respectively according to a ratio to obtain a first raw material liquid, a second raw material liquid, and a third raw material liquid;

[0008] S2: Input the first feed liquid, the second feed liquid, and the third feed liquid obtained in step S1 into a three-channel microreactor, control the reaction temperature at -20°C to -15°C, and the residence time at 8 to 10 minutes, and generate a fluorinated copolymer through stereoselective anionic polymerization. In step S2 of the present invention, by performing stereoselective anionic polymerization under low-temperature conditions, the generated fluorinated copolymer has a high proportion of cis configuration, which can significantly improve the elastic recovery ability of the polymer. At the same time, by using fluorinated olefin and 1,1,1,3,3,3-hexafluoro-2-propenimine as monomers for the reaction, due to the high hydrophobicity and low polarity of the trifluoromethyl and perfluoroalkyl chain segments introduced in 1,1,1,3,3,3-hexafluoro-2-propenimine, not only the chemical resistance and thermal stability of the fluorinated copolymer are further improved, but also it synergistically acts with the fluorinated groups in the fluorinated olefin, so that the porous sealing gasket prepared in the present invention has excellent chemical resistance, high temperature resistance, and mechanical properties.

[0009] S3: Introduce fluorinated graphene grafted with a surface RAFT chain transfer agent at the polymerization reaction outlet of the three-channel microreactor in step S2, and apply a shear rate of 500 to 800 s -1 to orient the FGN along the stretching direction; in step S3 of the present invention, by introducing fluorinated graphene grafted with a surface RAFT chain transfer agent, the mechanical properties and thermal stability of the polymer are enhanced. By applying a shear rate through a tapered channel to orient the FGN along the stretching direction, the degree of orientation of the material is improved, thereby enhancing the anisotropic properties of the material.

[0010] S4: Compound the polymer obtained in step S3 with natural rubber to form a composite colloid and inject it into a mold, perform dynamic vulcanization at 170 to 180°C and 4 to 6 MPa, and then introduce a supercritical CO2 foaming agent for foaming operation; in step S4 of the present invention, by simultaneously using dynamic vulcanization and a supercritical CO2 foaming agent, a three-dimensional interconnected porous structure is formed. The porous structure helps to improve the elastic recovery rate of the material while maintaining good compression properties. Compounding the fluorinated copolymer with natural rubber combines the high elasticity of natural rubber and the chemical resistance of the fluorinated copolymer, further optimizing the comprehensive properties of the material. By forming a porous structure, the material has higher molecular chain mobility at room temperature, thereby improving the elastic recovery ability. At the same time, the formation of the porous structure helps to reduce stress concentration and further optimize the elastic recovery ability of the material.

[0011] S5: After demolding, plasma surface fluorination treatment and hot pressing are carried out in sequence to obtain a porous sealing gasket with a high elastic recovery rate. In step S5 of the present invention, the plasma surface fluorination treatment not only enhances the chemical resistance and thermal stability of the material surface, but also optimizes the surface properties of the material, ensures the uniformity of the microstructure of the material, and avoids permanent deformation caused by stress concentration, thereby improving the elastic recovery ability of the material. The hot pressing further ensures the dimensional stability and shape retention ability of the material, and further improves the overall comprehensive performance of the material, enabling it to meet the requirements of long-term durability and stability.

[0012] As a preferred technical solution, the fluoroolefin is composed of (3E)-1,1,2-trifluoro-1,3-pentadiene and perfluoroolefinic ether. In the present invention, the high flexibility and low glass transition temperature (Tg) of the perfluoroether segment in the perfluoroolefinic ether significantly improve the elastic recovery ability of the polymer, while enhancing the chemical resistance and thermal stability of the material. In addition, the introduction of (3E)-1,1,2-trifluoro-1,3-pentadiene further improves the thermal stability and mechanical properties of the polymer, and optimizes the crystallization properties of the polymer; its unique cis configuration helps the regular arrangement of polymer chains, enabling it to maintain good flexibility and elastic recovery ability at low temperatures.

[0013] As a preferred technical solution, the perfluoroolefinic ether is perfluoroethyl vinyl ether and / or perfluoropropyl vinyl ether.

[0014] As a preferred technical solution, the initiator is a composite system of tert-butyl lithium and a chiral boron catalyst, and the molar ratio is 1:0.02 - 0.05. In the present invention, tert-butyl lithium, as a strong basic initiator, can efficiently initiate the polymerization reaction of fluoroolefin and 1,1,1,3,3,3-hexafluoro-2-propyleneimine, providing highly active polymerization sites. The chiral boron catalyst, through its unique catalytic mechanism, precisely regulates the stereoconfiguration of the polymer chain, ensuring that the resulting fluorinated copolymer has a high cis configuration ratio. The synergistic effect of the two makes this high cis configuration not only significantly improve the elastic recovery ability of the polymer, but also optimize the regularity and crystallization properties of the polymer chain.

[0015] As a preferred technical solution, in step S2, the channel material of the three-channel microreactor is silicon nitride ceramic, the channel cross-section is a rectangular structure of 200μm×500μm, and the Reynolds number Re is controlled within the range of 40 - 80. In the present invention, using a three-channel microreactor as the polymerization reaction vessel not only improves the reaction efficiency and stability, but also ensures the uniform distribution of polymer chains and reduces stress concentration points. This uniformity helps to improve the overall performance of the material, especially the elastic recovery ability.

[0016] As a preferred technical solution, the fluorinated graphene grafted with RAFT chain transfer agent on its surface is prepared by the following steps: First, disperse the fluorinated graphene in dimethyl sulfoxide, then add the RAFT chain transfer agent, and carry out the grafting reaction under nitrogen protection to obtain the fluorinated graphene grafted with RAFT chain transfer agent on its surface.

[0017] As a preferred technical solution, in the step S4, the injection rate of the supercritical CO2 foaming agent is 0.5 - 1.0 mL / min.

[0018] As a preferred technical solution, during the dynamic vulcanization process, di - tert - butyl peroxyisopropyl benzene is used as the dynamic cross - linker.

[0019] As a preferred technical solution, in the step S5, the process parameters of the plasma surface fluorination treatment are: power 200 - 300 W, treatment time 10 - 15 minutes, and the fluorination gas is a mixed gas of CF4 and Ar.

[0020] Another aspect of the present invention is to provide a porous sealing gasket with a high elastic recovery rate, and the porous sealing gasket is prepared by the preparation method of the porous sealing gasket with a high elastic recovery rate as described above.

[0021] Advantages of the present invention:

[0022] The preparation method of the porous sealing gasket with a high elastic recovery rate of the present invention, by innovatively introducing a fluorine - containing copolymer with a high cis - configuration and fluorinated graphene into the polymer chain, not only realizes the high elastic recovery rate of the sealing gasket, but also realizes excellent chemical resistance and high - temperature resistance. This design not only enhances the mechanical properties of the material, but also maintains good flexibility and elastic recovery ability, helps to reduce stress concentration, and further optimizes the overall performance of the material.

[0023] Generally speaking, the porous sealing gasket with a high elastic recovery rate of the present invention not only has excellent elastic recovery ability and chemical resistance, but also has good high - temperature resistance and mechanical strength, and can meet the long - term durability and stability requirements of sealing gaskets in high - performance application fields such as aerospace and the automotive industry. Specific embodiments

[0024] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations.

[0025] Example 1

[0026] The preparation method of the porous sealing gasket with a high elastic recovery rate in this example includes the following steps:

[0027] S1: Dissolve 36 g of fluorinated olefin (composed of 22 g of (3E)-1,1,2-trifluoro-1,3-pentadiene and 14 g of perfluoroethyl vinyl ether), 12 g of 1,1,1,3,3,3-hexafluoro-2-propanimine, and 0.05 g of initiator respectively in 100 mL of dimethyl sulfoxide solvent with the same volume to obtain the first feed liquid, the second feed liquid, and the third feed liquid; the initiator is a composite system of tert-butyl lithium and a chiral boron catalyst (diisopinocampheylchloroborane), and the molar ratio is 1:0.02.

[0028] S2: Input the first feed liquid, the second feed liquid, and the third feed liquid obtained in step S1 into a three-channel microreactor at a flow rate of 0.2 mL / min, control the reaction temperature at -15°C, and the residence time at 10 minutes to generate a fluorinated copolymer through stereoselective anionic polymerization. The channel material of the three-channel microreactor is silicon nitride ceramic, the channel cross-section is a rectangular structure of 200 μm × 500 μm, and the Reynolds number Re is controlled within the range of 40 - 80.

[0029] S3: Introduce 0.5 g of fluorinated graphene (FGN) grafted with RAFT chain transfer agent on the surface at the polymerization reaction outlet of the three-channel microreactor in step S2, and apply a shear rate of 500 s -1 , to align the FGN in the stretching direction.

[0030] S4: Compound the polymer obtained in step S3 with natural rubber at a mass ratio of 3:2 into a composite colloid and inject it into a mold, dynamically vulcanize at 170°C and 5 MPa for 15 minutes, and then introduce a small amount of supercritical CO2 foaming agent for 5 min of foaming operation. 0.15 g of bis(tert-butylperoxyisopropyl)benzene is used as the dynamic crosslinking agent during the dynamic vulcanization process. The injection rate of the supercritical CO2 foaming agent is 0.5 mL / min. The pressure of the supercritical CO2 foaming agent is 10 MPa, and the temperature is 35°C.

[0031] S5: After demolding, perform plasma surface fluorination treatment and hot pressing and shaping in sequence to obtain a porous sealing gasket with a high elastic recovery rate. The process parameters of the plasma surface fluorination treatment are: power 300 W, treatment time 10 minutes, and the fluorination gas is a mixed gas of CF4 and Ar (volume ratio 1:3). The hot pressing and shaping temperature is 180°C, the pressure is 8 MPa, and the time is 30 minutes.

[0032] The fluorinated graphene grafted with RAFT chain transfer agent on its surface is prepared by the following steps: First, weigh 1 g of fluorinated graphene and disperse it in 50 mL of dimethyl sulfoxide (DMSO), and perform ultrasonic treatment for 30 minutes to ensure uniform dispersion. Subsequently, add 0.5 g of RAFT chain transfer agent (2-cyano-5-hydroxy-2-pentylbenzene dithiocarboxylate), and carry out the grafting reaction under nitrogen protection. The reaction temperature is controlled at 80 °C ± 5 °C, and the reaction time is 12 hours. After the reaction is completed, cool the reaction mixture to room temperature, collect the solid product by centrifugal separation, and wash it 3 times with absolute ethanol to remove the unreacted RAFT chain transfer agent and impurities. Finally, dry it in vacuum at 60 °C for 12 hours to obtain the fluorinated graphene grafted with RAFT chain transfer agent on its surface.

[0033] Example 2

[0034] The preparation method of the porous sealing gasket with high elastic recovery rate in this example includes the following steps:

[0035] S1: Dissolve 40 g of fluorinated olefin (composed of 26 g of (3E)-1,1,2-trifluoro-1,3-pentadiene and 14 g of perfluoropropyl vinyl ether), 15 g of 1,1,1,3,3,3-hexafluoro-2-propylideneimine and 0.05 g of initiator in 100 mL of dimethyl sulfoxide solvent with the same volume respectively to obtain the first raw material liquid, the second raw material liquid and the third raw material liquid; the initiator is a composite system of tert-butyl lithium and chiral boron catalyst (diisopinocampheylchloroborane), and the molar ratio is 1:0.03.

[0036] S2: Input the first raw material liquid, the second raw material liquid and the third raw material liquid obtained in step S1 into a three-channel microreactor at a flow rate of 0.25 mL / min, control the reaction temperature at -15 °C, and the residence time at 8 minutes, and generate a fluorinated copolymer through stereoselective anionic polymerization. The channel material of the three-channel microreactor is silicon nitride ceramic, the cross-section of the channel is a rectangular structure of 200 μm × 500 μm, and the Reynolds number Re is controlled within the range of 40 - 80.

[0037] S3: Introduce 0.6 g of fluorinated graphene (FGN) grafted with RAFT chain transfer agent on its surface at the polymerization reaction outlet of the three-channel microreactor in step S2, and apply a shear rate of 600 s -1 to make the FGN align in the stretching direction.

[0038] S4: Mix the polymer obtained in step S3 and natural rubber according to a mass ratio of 3:2 to form a composite colloid, inject it into a mold, perform dynamic vulcanization at 175 °C and 6 MPa for 15 minutes, and then introduce a small amount of supercritical CO2 foaming agent for 5 minutes of foaming operation. 0.15 g of bis(tert-butylperoxyisopropyl)benzene is used as the dynamic crosslinking agent during the dynamic vulcanization process. The injection rate of the supercritical CO2 foaming agent is 0.7 mL / min. The pressure of the supercritical CO2 foaming agent is 10 MPa and the temperature is 35 °C.

[0039] S5: After demolding, perform plasma surface fluorination treatment and hot pressing and shaping in sequence to obtain a porous sealing gasket with a high elastic recovery rate. The process parameters of the plasma surface fluorination treatment are: power 250 W, treatment time 12 minutes, and the fluorination gas is a mixed gas of CF4 and Ar (volume ratio 1:3). The hot pressing and shaping temperature is 180 °C, the pressure is 8 MPa, and the time is 30 minutes.

[0040] The fluorinated graphene grafted with the surface RAFT chain transfer agent is the same as in Example 1.

[0041] Example 3

[0042] The preparation method of the porous sealing gasket with a high elastic recovery rate in this example includes the following steps:

[0043] S1: Dissolve 45 g of fluorinated olefin (composed of 30 g of (3E)-1,1,2-trifluoro-1,3-pentadiene and 15 g of perfluoroethyl vinyl ether), 18 g of 1,1,1,3,3,3-hexafluoro-2-propanimine, and 0.05 g of initiator in 100 mL of dimethyl sulfoxide solvent with the same volume to obtain a first raw material liquid, a second raw material liquid, and a third raw material liquid; the initiator is a composite system of tert-butyl lithium and a chiral boron catalyst (diisopinocampheylchloroborane), and the molar ratio is 1:0.05.

[0044] S2: Input the first raw material liquid, the second raw material liquid, and the third raw material liquid obtained in step S1 into a three-channel microreactor at a flow rate of 0.3 mL / min, control the reaction temperature at -20 °C, and the residence time at 8 minutes, and generate a fluorinated copolymer through stereoselective anionic polymerization. The channel material of the three-channel microreactor is silicon nitride ceramic, the channel cross-section is a 200 μm × 500 μm rectangular structure, and the Reynolds number Re is controlled within the range of 40 - 80.

[0045] S3: Introduce 0.7 g of fluorinated graphene (FGN) grafted with a surface RAFT chain transfer agent at the polymerization reaction outlet of the three-channel microreactor in step S2, and apply a shear rate of 800 s -1 , so that the FGN is oriented along the stretching direction.

[0046] S4: Mix the polymer obtained in step S3 and natural rubber according to a mass ratio of 3:2 to form a composite colloid, inject it into a mold, dynamically vulcanize it at 180 °C and 6 MPa for 15 minutes, and then introduce a small amount of supercritical CO2 foaming agent for a 5-minute foaming operation. 0.15 g of bis(tert-butylperoxyisopropyl)benzene is used as the dynamic crosslinking agent during the dynamic vulcanization process. The injection rate of the supercritical CO2 foaming agent is 1.0 mL / min. The pressure of the supercritical CO2 foaming agent is 10 MPa, and the temperature is 35 °C.

[0047] S5: After demolding, perform plasma surface fluorination treatment and hot pressing and shaping in sequence to obtain a porous sealing gasket with a high elastic recovery rate. The process parameters of the plasma surface fluorination treatment are: power 300 W, treatment time 10 minutes, and the fluorination gas is a mixed gas of CF4 and Ar (volume ratio 1:3). The hot pressing and shaping temperature is 180 °C, the pressure is 8 MPa, and the time is 30 minutes.

[0048] The fluorinated graphene grafted with the surface RAFT chain transfer agent is the same as in Example 1.

[0049] Comparative Example 1

[0050] The preparation method of the porous sealing gasket with a high elastic recovery rate in this comparative example is basically the same as that in Example 1 in terms of raw material composition and preparation steps. The difference is that in the preparation method of this comparative example, the fluorinated olefin is only (3E)-1,1,2-trifluoro-1,3-pentadiene.

[0051] Comparative Example 2

[0052] The preparation method of the porous sealing gasket with a high elastic recovery rate in this comparative example is basically the same as that in Example 1 in terms of raw material composition and preparation steps. The difference is that in the preparation method of this comparative example, the fluorinated olefin is only perfluoroethyl vinyl ether.

[0053] Comparative Example 3

[0054] The preparation method of the porous sealing gasket with a high elastic recovery rate in this comparative example is basically the same as that in Example 1 in terms of raw material composition and preparation steps. The difference is that in the preparation method of this comparative example, the initiator is only tert-butyl lithium.

[0055] Comparative Example 4

[0056] The preparation method of the porous sealing gasket with a high elastic recovery rate in this comparative example is basically the same as that in Example 1 in terms of raw material composition and preparation steps. The difference is that in the preparation method of this comparative example, the operation of step S3 is omitted.

[0057] Perform performance tests on the porous sealing gaskets prepared in Examples 1 to 3 and Comparative Examples 1 to 4, and the performance results are shown in Table 1:

[0058] Among them, the test of the elastic recovery rate is based on GB / T 528 "Rubber, vulcanized or thermoplastic - Determination of tensile stress - strain properties". The specific test conditions are as follows: The sample is stretched to 300% strain and then released, and the elastic recovery rate is calculated by measuring the change in length after recovery. This index reflects the ability of the material to return to its original state after being stretched. The higher the value, the stronger the elastic recovery ability of the material.

[0059] The test of the compression set is based on GB / T 7757 "Rubber, vulcanized or thermoplastic - Determination of compressive stress - strain properties". The specific test conditions are as follows: The sample is maintained at 150 °C for 70 hours with a compression rate of 25%. The anti - deformation ability of the material is evaluated by measuring the degree of permanent deformation after compression. The lower the value, the better the dimensional stability of the material under high temperature and high pressure.

[0060] The test of thermal stability is based on GB / T 1634 "Plastics - Determination of heat distortion temperature under load". The specific test conditions are as follows: The heating rate is 2 °C / min and the load is 0.45 MPa. The heat distortion temperature of the material under the specified load is determined by a heat distortion tester. The higher the value, the better the high - temperature resistance of the material.

[0061] The test of chemical resistance is based on ISO 1817 "Rubber, vulcanized, or thermoplastic elastomers - Determination of resistance to liquids". The specific test conditions are as follows: The sample is immersed in 30% sulfuric acid, 30% sodium hydroxide, and toluene for 7 days at room temperature. The chemical resistance of the material is evaluated by observing the performance changes of the sample in different chemical media. The results are divided into grades such as "excellent", "good", "general", etc. The higher the value or the higher the grade, the better the chemical resistance of the material.

[0062] Table 1

[0063] Project Elastic recovery rate, % Compression set rate, % Thermal stability, °C Chemical resistance Example 1 98 7 318 Excellent Example 2 97 8 314 Excellent Example 3 98 6 320 Excellent Comparative Example 1 87 12 286 Good Comparative Example 2 92 9 292 Good Comparative Example 3 91 10 304 Good Comparative Example 4 96 12 282 Excellent

[0064] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above - mentioned embodiments. What is described in the above - mentioned embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A method for preparing a porous sealing gasket with high elastic recovery rate, characterized in that: The preparation method comprises the following steps: S1: dissolving fluorinated olefin, 1,1,1,3,3,3-hexafluoro-2-propyleneimine and an initiator in a solvent in proportion to obtain a first raw material solution, a second raw material solution and a third raw material solution; the fluorinated olefin is composed of (3E)-1,1,2-trifluoro-1,3-pentadiene and perfluoroolefin ether; the initiator is a composite system of tert-butyl lithium and a chiral boron catalyst, and the molar ratio is 1:0.02-0.05; S2: The first raw material solution, the second raw material solution and the third raw material solution obtained in step S1 are input into a three-channel microreactor, the reaction temperature is controlled to be -20°C to -15°C, the residence time is 8 to 10 minutes, and a fluorinated copolymer is generated by stereoselective anionic polymerization; S3: Introduce fluorinated graphene with surface grafted RAFT chain transfer agent at the polymerization outlet of the three-channel microreactor in step S2, and apply a shear rate of 500-800s through the conical flow channel -1 , so that the FGN is oriented along the stretching direction; S4: Compounding the polymer obtained in step S3 with natural rubber to form a composite colloid, injecting it into a mold, dynamically vulcanizing it at 170-180° C. and 4-6 MPa, and then introducing a supercritical CO2 foaming agent for foaming operation; S5: After demoulding, plasma surface fluorination treatment and hot pressing are performed in sequence to obtain a porous sealing gasket with a high elastic recovery rate.

2. The method for preparing a porous sealing gasket with high elastic recovery rate according to claim 1, characterized in that: The perfluoroolefin ether is perfluoroethyl vinyl ether and / or perfluoro-n-propyl vinyl ether.

3. The method for preparing a porous sealing gasket with high elastic recovery rate according to claim 1, characterized in that: In the step S2, the channel material of the three-channel microreactor is silicon nitride ceramic, the channel cross section is a 200 μm×500 μm rectangular structure, and the Reynolds number Re is controlled within the range of 40 to 80.

4. The method for preparing a porous sealing gasket with high elastic recovery rate according to claim 1, characterized in that: The fluorinated graphene with a RAFT chain transfer agent grafted on the surface is prepared by the following steps: firstly, dispersing the fluorinated graphene in dimethyl sulfoxide, then adding a RAFT chain transfer agent, and performing a grafting reaction under nitrogen protection to obtain the fluorinated graphene with a RAFT chain transfer agent grafted on the surface.

5. The method for preparing a porous sealing gasket with high elastic recovery rate according to claim 1, characterized in that: In step S4, the injection rate of the supercritical CO2 foaming agent is 0.5-1.0 mL / min.

6. The method for preparing a porous sealing gasket with high elastic recovery rate according to claim 1, characterized in that: In the dynamic vulcanization process, di-tert-butyl peroxyisopropylbenzene is used as a dynamic crosslinking agent.

7. The method for preparing a porous sealing gasket with high elastic recovery rate according to claim 1, characterized in that: In step S5, the process parameters of the plasma surface fluorination treatment are: power 200-300W, treatment time 10-15 minutes, and the fluorination gas is a mixed gas of CF4 and Ar.

8. A porous sealing gasket with high elastic recovery rate, characterized in that: The porous sealing gasket is prepared by the method for preparing a porous sealing gasket with high elastic recovery rate according to any one of claims 1 to 7.