A high-strength thermomagnetized reinforced fluorine-containing composite material and its preparation method

Abstract

This invention discloses a high-strength thermomagnetically reinforced fluorinated composite material and its preparation method, belonging to the field of fluoropolymer molding and processing. The steps include: etching filler under heating and magnetic field conditions; mixing a sizing grafting agent with the magnetized etching filler under another heating and magnetic field condition to modify the magnetized etching filler with polar molecules; mixing fluorinated resin powder with the magnetized modified filler; molding the mixture in a mold located in a magnetic field; sintering the magnetized filler-modified green body; and when the temperature drops to the solidification temperature, removing it and cooling it in water located in a magnetic field. This invention combines heat and magnetism to provide energy, utilizing the characteristics of heating to increase the reaction rate and magnetization to facilitate the change and directional arrangement of polar molecular dipole moments. It performs directional magnetization modification on the filler used to modify fluorinated materials, enhancing the modification effect of the filler interface, resulting in the directional distribution of the filler in the composite material, and improving the mechanical properties and wear resistance of the material.

Description

Technical Field

[0001] This invention relates to a high-strength thermomagnetized reinforced fluorine-containing composite material and its preparation method, belonging to the field of fluoropolymer molding and processing. Background Technology

[0002] With the rapid development of high-end technical equipment, high-pressure and high-temperature special working conditions place higher demands on the mechanical properties of polymer materials, such as compressive strength and elastic modulus, especially for industrial components such as step seals and Glyd rings that require high wear resistance and high compressive strength. Fluorine-containing materials have attracted much attention due to their excellent mechanical properties. However, even after being reinforced and filled with ordinary materials, fluorine-containing materials still face disadvantages such as low compressive strength and easy wear. When used as oil seal materials, they are prone to fatigue damage due to excessive local stress and low strength, which can lead to the failure of key components such as oil seals and affect the service life of equipment. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention provides a high-strength thermomagnetized reinforced fluorine-containing composite material and its preparation method, which can improve the interfacial bonding performance between the fluorine-containing material matrix and the reinforcing filler, thereby improving the problem of low strength and modulus of fluorine-containing materials.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] In a first aspect, this application provides a method for preparing a high-strength thermomagnetized reinforced fluorine-containing composite material, comprising the following steps:

[0006] Under heating and magnetic field conditions, the filler is corroded with a corrosive solution, filtered, and dried to obtain magnetized corroded filler.

[0007] Under heating and magnetic field conditions, the sizing grafting agent is mixed with the magnetized corrosion filler to modify the magnetized corrosion filler with the polar molecules of the sizing grafting agent. The mixture is then filtered and dried to obtain the magnetized modified filler.

[0008] Fluorine-containing resin powder is mixed with the magnetized modified filler, and then molded in a mold located in a magnetic field to obtain a magnetized filler modified green body.

[0009] The magnetized filler-modified green body is sintered, and when the temperature drops to the solidification temperature, it is taken out and placed in water located in a magnetic field for cooling to obtain the high-strength thermomagnetized reinforced fluorine-containing composite material.

[0010] The high-strength thermomagnetized reinforced fluorine-containing composite material preparation method provided in this application proposes a filler interface modification technology and a mixing technology based on thermomagnetization technology, which can improve the interfacial bonding performance between the fluorine-containing material matrix and the reinforcing filler. The filler is then applied to the fluorine-containing material, giving the fluorine-containing composite material higher strength and modulus, which can be applied to the working conditions of anti-compression friction pairs.

[0011] Furthermore, the filler is selected from at least one of carbon fiber, glass fiber, graphite, molybdenum disulfide, silicon dioxide, titanium dioxide, silicon carbide, silicon nitride, potassium titanate whiskers, and whisker carbon nanotubes.

[0012] Furthermore, the corrosive solution is selected from at least one of sulfuric acid, nitric acid, hydrochloric acid, 5-10% sodium hydroxide, 5-10% potassium hydroxide, hydrofluoric acid, phosphoric acid, persulfate, and permanganate.

[0013] Furthermore, in the step of corroding the filler with a corrosive solution under heating and magnetic field conditions, the mass ratio of the corrosive solution to the filler is 10:1, the heating temperature is 50℃~80℃, the magnetic field strength is 3000Gs~6000Gs, and the treatment time is 30min~60min.

[0014] Under these conditions, directional corrosion can be formed, which mainly enhances corrosion and improves activation efficiency. After subsequent grafting, the sizing grafting agent with polar groups will impart a certain magnetization effect to the filler under the action of a magnetic field, thereby producing a small directional effect.

[0015] Furthermore, the solute of the sizing grafting agent is selected from at least one of aminopropyltriethoxysilane, aminopropyltrimethylsilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, methacryloxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, γ-mercaptopropyltrimethoxysilane, tridecafluorooctyltriethoxysilane, perfluoropolyether siloxane, tridecafluorooctyltrimethoxysilane, fluorocarbon surfactant, polyurethane, polyurethane acrylate, polyimide, and sulfonated polyether ether ketone.

[0016] After grafting, the grafting agent with polar groups will grow on the filler, and in the subsequent magnetic field environment, the filler will also have a directional arrangement effect.

[0017] Furthermore, the mass concentration of the sizing grafting agent is 5%, and the mass ratio of the magnetized corrosion filler to the sizing grafting agent is 1:6.

[0018] Furthermore, in the step of mixing the sizing grafting agent with the magnetized corrosion filler under heating and magnetic field conditions, the temperature is first raised to 50°C at 5°C / min under a magnetic field of 5000Gs and held for 30min. Then, the magnetic field is increased to 13000Gs and the temperature is raised to 80°C at 2°C / min and held for 30min. Finally, the magnetic field is removed.

[0019] Furthermore, in the step of mixing the fluorinated resin powder with the magnetized modified filler and molding it in a mold located in a magnetic field, the magnetic field strength is 3000Gs~6000Gs, the mass ratio of the fluorinated resin powder to the magnetized modified filler is 4:1, the cavity of the mold is a hollow column, and the magnetic pole line of the magnetic field coincides with the axis of the cavity.

[0020] Furthermore, in the step of removing the object and placing it in water located in a magnetic field for cooling, the magnetic field strength is 4000 Gs and the time is 30 min to 50 min.

[0021] This magnetization cooling technology can effectively cool materials deeply, resulting in a better improvement in the mechanical properties of composite materials.

[0022] Secondly, this application provides a high-strength thermomagnetized reinforced fluorine-containing composite material, which is prepared by the method described in the first aspect. The molded fluorine-containing composite material has high strength and good wear resistance, and can be widely used in the molding and preparation of seals under high-speed operating conditions.

[0023] The beneficial effects of this invention are as follows: This invention utilizes the low surface energy of fluorine-containing substrates and the characteristic of magnetization enhancing activation energy, combining heat and magnetism to provide energy. By using heating to increase the reaction rate and magnetization to facilitate the change of dipole moment and directional arrangement of polar molecules, the filler used to modify fluorine-containing materials is directionally magnetized and modified. Through thermomagnetization technology, not only is the modification effect of the filler interface enhanced, but the filler is also directionally distributed in the composite material, thereby improving the mechanical properties and wear resistance of the material.

[0024] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0025] Figure 1 This is a schematic flowchart of a method for preparing a high-strength thermomagnetized reinforced fluorine-containing composite material according to an embodiment of this application.

[0026] Figure 2 This is a schematic diagram of the processing steps S1 or S2.

[0027] Figure 3 This is a schematic diagram of the processing steps in step S3.

[0028] Figure 4 These are compression test curves for each embodiment and comparative example.

[0029] Figure 5 These are the pressure friction coefficient curves for each embodiment and comparative example.

[0030] Figure 6 These are white light images of the abrasion marks of the materials prepared in Example 1 and Comparative Example 5. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this invention.

[0032] It should be understood that, without conflict, any and all embodiments of the present invention can be combined with technical features of any other embodiment or multiple other embodiments to obtain other embodiments. The present invention includes such combinations to obtain other embodiments.

[0033] In this specification, groups and their substituents may be selected by those skilled in the art to provide stable structural moieties and compounds. When a substituent is described by a conventional chemical formula written from left to right, the substituent also includes chemically equivalent substituents obtained when the structural formula is written from right to left.

[0034] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter pertains. Where multiple definitions exist for a term, the definition herein shall prevail.

[0035] Reference Figure 1 This application provides a method for preparing a high-strength thermomagnetized reinforced fluorine-containing composite material, comprising the following steps:

[0036] S1: The filler is corroded with a corrosive solution under heating and magnetic field conditions, filtered and dried to obtain magnetized corroded filler.

[0037] S2: Under heating and magnetic field conditions, the sizing grafting agent is mixed with the magnetized corrosion filler to modify the magnetized corrosion filler with the polar molecules of the sizing grafting agent. After filtration and drying, the magnetized modified filler is obtained.

[0038] S3: Fluorine-containing resin powder is mixed with magnetized modified filler and molded in a mold located in a magnetic field to obtain a green body modified with magnetized filler.

[0039] S4: Sintered magnetized filler modified green body, when the temperature drops to the solidification temperature (of fluororesin), is taken out and placed in water in a magnetic field to cool, to obtain high-strength thermomagnetized reinforced fluorocomposite material.

[0040] This invention addresses the issue of high CF bond energy and low surface activity in fluorinated materials, making it difficult to form a strong anchoring relationship with reinforcing materials at the interface. This leads to easy detachment of the reinforcing material from the fluorinated substrate at the interface, reducing the compressive strength and tribological properties of the composite material. Considering the modifiable interface of fillers used to reinforce fluoropolymers (hereinafter referred to as reinforcing fillers), this invention combines thermomagnetic interface activation and mixing techniques. By modifying the reinforcing filler interface with polar molecules in a thermomagnetic magnetic field, the modification effect of the reinforcing filler is improved. Furthermore, through magnetized mixing technology, the magnetized reinforcing filler (magnetized modified filler) is arranged regularly within the fluorinated material, thereby improving the mechanical and tribological properties of the fluorinated composite material. This method is simple and efficient. Fillers modified using this method enable fluorinated composite materials to possess higher compressive strength and elastic modulus, as well as improved tribological properties.

[0041] Specifically, this can be achieved through the following process steps:

[0042] 1. In a container, the filler and the corrosive solution are mixed evenly under stirring at a weight ratio of 1:10 to ensure that the filler interface is in full contact with the corrosive solution.

[0043] 2. The container containing the filler and corrosive solution from step 1 is heated to a certain temperature, and the heating device is placed in a magnetizer with a certain magnetic field strength to heat and magnetize it for a period of time. Figure 2 As shown.

[0044] 3. After the magnetization process in step 2 is completed, filter the mixed solution and dry the packing material.

[0045] 4. Mix the magnetized and corroded filler (magnetized and corroded filler) from step 3 with a 5% sizing grafting agent at a ratio of 1:6. Heat the mixture using a programmed heating method and place it in a magnetizer with a programmable magnetic field strength. Heat the mixture and magnetize it according to a specific magnetic field strength for a period of time.

[0046] 5. After the magnetization process in step 4 is completed, filter the mixed solution and dry the packing material to obtain the packing material modified based on thermomagnetization technology (magnetized modified packing material).

[0047] In this embodiment of the application, the fluorine-containing composite material based on magnetization technology can be achieved through the following steps:

[0048] 6. The filler modified by thermomagnetization technology and the fluorine-containing material are mixed evenly in a high-speed mixer at a weight ratio of 1:4.

[0049] 7. Reference Figure 3 Slowly pour the mixed powder prepared in step 6 into the mold, apply a magnetic field with a certain direction and intensity to the mold, and fill the mold with the mixed powder until it is full.

[0050] 8. After step 7 is completed, apply pressure of 80MPa to the powder in the mold under the action of the press head, and maintain it for 30 minutes to set the shape.

[0051] 9. After the molding process in step 8 is completed, demold the fluorine-containing composite material green blank (magnetized filler modified green blank) and place it in a sintering furnace for sintering treatment at a specific sintering temperature and hold for 2 hours.

[0052] 10. When the sintering furnace temperature drops to 320°C, remove the sintered material and immediately place it in water with a certain magnetic field to magnetize it and cool it for a period of time.

[0053] 11. After magnetization and cooling are complete, the material can be removed to obtain a high-strength thermomagnetized reinforced fluorine-containing composite material.

[0054] Among them, the fluorine-containing materials are one or more of the following: polytetrafluoroethylene, polyvinylidene fluoride, perfluoroethylene propylene, soluble polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, and polychlorotrifluoroethylene.

[0055] The reinforcing filler is one or more of the following: carbon fiber, glass fiber, graphite, molybdenum disulfide, silicon dioxide, titanium dioxide, silicon carbide, silicon nitride, potassium titanate whiskers, and whisker carbon nanotubes. This application modifies existing commonly used filler formulations, rather than directly selecting novel fillers with inherent magnetic properties. This avoids the hassle of re-evaluating other material properties to ensure suitability for fluoropolymers when using magnetic materials not previously used for fluoropolymer reinforcement.

[0056] In this application, the etching solution is one or more of the following: sulfuric acid, nitric acid, hydrochloric acid, 5-10% sodium hydroxide, 5-10% potassium hydroxide, hydrofluoric acid, phosphoric acid, persulfate, and permanganate. Of course, the etching solution and the filler are not arbitrarily combined; rather, a suitable etching solution is selected based on the filler. For example, silicon dioxide is etched with an alkaline etching solution; carbon materials are etched with acids or strong oxidizing agents; and silicon nitride is etched with hydrofluoric acid. Modified fillers generally have fewer surface active sites and lower interfacial energies. The etching solution can effectively increase the activation energy of the filler interface, increase the number of reactive active sites, and thus enable it to have a wider range of applications.

[0057] In step S1, the heating temperature is 50~80℃, the magnetic field strength of the magnetizer is 3000~6000Gs, and the magnetization time is 30~60min. The use of thermomagnetization technology in the corrosion solution treatment process can effectively refine the size of the corrosion solution clusters, reduce the minimum energy required for the filler to participate in the chemical reaction, and allow the polar corrosive agent to form a directional distribution under the influence of the magnetic field, enhancing the directional corrosion effect on the filler.

[0058] The solute of the sizing grafting agent is at least one of the following: aminopropyltriethoxysilane, aminopropyltrimethylsilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, methacryloyloxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, γ-mercaptopropyltrimethoxysilane, tridecafluorooctyltriethoxysilane, or perfluoropolyether siloxane or tridecafluorooctyltrimethoxysilane; or a fluorocarbon surfactant; or it can be a polymer material such as polyurethane, polyurethane acrylate, polyimide, or sulfonated polyether ether ketone.

[0059] The heating procedure for sizing and grafting in step S2 is as follows:

[0060] The temperature is increased from room temperature to 50℃ at a rate of 5℃ / min and held for 30 minutes, then increased to 80℃ at a rate of 2℃ / min and held for 30 minutes.

[0061] The magnetization process is as follows:

[0062] After magnetization for 30 minutes in a magnetic field of 5000 Gs, the magnetization was then carried out for 30 minutes in a magnetic field of 13000 Gs, after which the magnetic field was removed.

[0063] Because the sizing grafting agent contains polar groups, it can break down from a connective structure into smaller molecules (except for polymers) in a magnetic field. The dipole moment of the polar groups in the sizing grafting agent changes, resulting in directional alignment. This allows it to effectively aggregate at the interface of the corrosion-modified filler. At the same time, magnetization technology can lower the reaction threshold and enhance the reactive sites, thereby increasing the reaction efficiency between the sizing grafting agent and the filler and improving the sizing effect of the sizing grafting agent.

[0064] In step S3, the magnetic field strength is 3000~6000 Gs. Furthermore, the mold cavity is a hollow cylindrical shape, and the line connecting the magnetic poles coincides with the axis of the cavity, as shown below. Figure 3 As shown. This magnetic pole direction allows the filler to be oriented parallel to the material's axis, resulting in better mechanical properties for materials of a certain thickness.

[0065] In step S4, the magnetic field strength is 4000 Gs, and the magnetization time is 30-50 min. Cooling is achieved using water magnetization technology, which effectively alters the dipole moment of water molecules, disrupts the cluster structure of water molecules, and enhances the activation ability of water molecules, resulting in better cooling performance. Preferably, in step S4, the magnetic pole line of the magnetic field coincides with the axis of the cavity.

[0066] This application employs thermomagnetization technology, which, through processes such as filler modification, molding, sintering, and cooling, allows the filler to fully react with the corrosive solution and the sizing grafting agent, enhancing the bonding ability between the resin matrix and the filler. At the same time, the magnetization cooling technology can effectively cool the material deeply, resulting in better mechanical properties of the composite material.

[0067] Example 1

[0068] 1. Mix 3g of carbon fiber powder with 30g of sulfuric acid under mechanical stirring to ensure that the carbon fiber and sulfuric acid solvent are in full contact.

[0069] 2. Heat the mixture of carbon fiber and sulfuric acid from step 1 to 80°C, and place the heating device in a magnetizer with a magnetic field strength of 6000 Gs to heat and magnetize it for 30 minutes.

[0070] 3. After the magnetization in step 2 is completed, pour the mixed solution into ice water and then into the suction filter. Wash the carbon fiber several times to bring the pH to around 7, and then dry it for later use.

[0071] 4. Dissolve 0.9g of tridecafluorooctyltrimethoxysilane in 17.1g of ethanol. After the silane is dispersed, completely disperse the acidified carbon fiber dried and prepared in step 3 in the ethanol mixture, and process it according to the heating procedure and magnetization procedure for sizing and grafting.

[0072] 5. After step 4 is completed, the carbon fiber powder is filtered, washed, and dried for later use, thus obtaining the carbon fiber modified by the thermomagnetization process.

[0073] 6. Mix 12g of polytetrafluoroethylene powder and the thermomagnetized modified carbon fiber obtained in step 5 thoroughly in a high-speed mixer.

[0074] 7. Slowly add the mixture into a cold-pressing mold with a magnetic field strength of 3000Gs.

[0075] 8. Place the mold in a pressure device and apply 80MPa pressure to the mixture using a cold pressing method. Maintain the pressure for 30 minutes to solidify it and form a green compact.

[0076] 9. After the molding process is completed, remove the green billet from the mold and place it in the sintering furnace. Set the sintering temperature of the sintering furnace to 370℃ and the holding time to 2 hours. After the holding time is completed, allow it to cool with the furnace.

[0077] 10. After the sintering process is completed and the furnace temperature has cooled to 320°C, remove the sintered material and place it in room temperature water with a magnetic field strength of 4000 Gs to magnetize it and cool it for 30 minutes.

[0078] 11. After cooling, the sintered material is removed from the water to obtain a high-strength thermomagnetized reinforced polytetrafluoroethylene composite material.

[0079] Example 2

[0080] 1. Mix 5g of glass fiber powder with 50g of 10% sodium hydroxide solution under mechanical stirring to ensure that the glass fiber and sodium hydroxide solution are in full contact.

[0081] 2. Heat the mixture of glass fiber and sodium hydroxide from step 1 to 50°C, and place the heating device in a magnetizer with a magnetic field strength of 3000 Gs to heat and magnetize it for 60 min.

[0082] 3. After the magnetization in step 2 is completed, pour the mixed solution into ice water and then into the vacuum filter. Wash it several times to bring the pH of the glass fiber to around 7, and then dry it for later use.

[0083] 4. Dissolve 1.5g of aminopropyltriethoxysilane in 28.5g of ethanol. After the silane is dispersed, completely disperse the glass fiber dried in step 3 in the ethanol mixture, and process it according to the heating and magnetization procedures for sizing and grafting.

[0084] 5. After step 4 is completed, the glass fiber powder is filtered, washed and dried for later use, thus obtaining the glass fiber modified by the thermomagnetization process.

[0085] 6. Mix 20g of soluble polytetrafluoroethylene powder and the thermomagnetized glass fiber obtained in step 5 thoroughly in a high-speed mixer.

[0086] 7. Slowly add the mixture into a cold-pressing mold with a magnetic field strength of 6000Gs.

[0087] 8. Place the mold in a pressure device and apply 80MPa pressure to the mixture using a cold pressing method. Maintain the pressure for 30 minutes to solidify it and form a green compact.

[0088] 9. After the molding process is completed, remove the green billet from the mold and place it in the sintering furnace. Set the sintering temperature of the sintering furnace to 350℃ and the holding time to 2 hours. After the holding time is completed, allow it to cool with the furnace.

[0089] 10. After the sintering process is completed and the furnace temperature has cooled to 320°C, remove the sintered material and place it in room temperature water with a magnetic field strength of 4000 Gs to magnetize it and cool it for 50 minutes.

[0090] 11. After cooling, the sintered material is removed from the water to obtain a high-strength thermomagnetized reinforced soluble polytetrafluoroethylene composite material.

[0091] Comparative Example 1

[0092] 1. Mix 3g of carbon fiber powder with 30g of sulfuric acid under mechanical stirring to ensure that the carbon fiber and sulfuric acid solvent are in full contact.

[0093] 2. Heat the mixture of carbon fiber and sulfuric acid from step 1 to 80°C, and place the heating device in a magnetizer with a magnetic field strength of 6000 Gs to heat and magnetize it for 30 minutes.

[0094] 3. After the magnetization in step 2 is completed, pour the mixed solution into ice water and then into the suction filter. Wash the carbon fiber several times to bring the pH to around 7, and then dry it for later use.

[0095] 4. Dissolve 0.9g of tridecafluorooctyltrimethoxysilane in 17.1g of ethanol. After the silane is dispersed, completely disperse the acidified carbon fiber dried in step 3 in the ethanol mixture. Stir the ethanol mixture and heat it to 80°C and maintain it for 60 minutes.

[0096] 5. After step 4 is completed, the carbon fiber powder is filtered, washed, and dried for later use to obtain modified carbon fiber.

[0097] 6. Mix 12g of polytetrafluoroethylene powder and the modified carbon fiber obtained in step 5 thoroughly in a high-speed mixer.

[0098] 7. Slowly add the mixture into the special cold-pressing mold.

[0099] 8. Place the mold in a pressure device and apply 80MPa pressure to the mixture using a cold pressing method. Maintain the pressure for 30 minutes to solidify it and form a green compact.

[0100] 9. After the molding process is completed, remove the green billet from the mold and place it in the sintering furnace. Set the sintering temperature of the sintering furnace to 370℃ and the holding time to 2 hours. After the holding time is completed, allow it to cool with the furnace.

[0101] 10. After the sintering process is completed and the furnace temperature has cooled to 320°C, remove the sintered material and place it in room temperature water to cool for 30 minutes.

[0102] 11. After cooling, the sintered material is removed from the water to obtain the polytetrafluoroethylene composite material of Comparative Example 1.

[0103] Comparative Example 2

[0104] 1. Mix 3g of carbon fiber powder with 30g of sulfuric acid under mechanical stirring to ensure that the carbon fiber and sulfuric acid solvent are in full contact.

[0105] 2. Heat the mixture of carbon fiber and sulfuric acid from step 1 to 80°C and heat for 30 minutes with stirring.

[0106] 3. After step 2 is completed, pour the mixed solution into ice water and then into the suction filter. Wash the carbon fiber several times to bring the pH to around 7, and then dry it for later use.

[0107] 4. Dissolve 0.9g of tridecafluorooctyltrimethoxysilane in 17.1g of ethanol. After the silane is dispersed, completely disperse the acidified carbon fiber dried and prepared in step 3 in the ethanol mixture, and process it according to the heating procedure and magnetization procedure for sizing and grafting.

[0108] 5. After step 4 is completed, the carbon fiber powder is filtered, washed, and dried for later use to obtain modified carbon fiber.

[0109] 6. Mix 12g of polytetrafluoroethylene powder and the modified carbon fiber obtained in step 5 thoroughly in a high-speed mixer.

[0110] 7. Slowly add the mixture into the special cold-pressing mold.

[0111] 8. Place the mold in a pressure device and apply 80MPa pressure to the mixture using a cold pressing method. Maintain the pressure for 30 minutes to solidify it and form a green compact.

[0112] 9. After the molding process is completed, remove the green billet from the mold and place it in the sintering furnace. Set the sintering temperature of the sintering furnace to 370℃ and the holding time to 2 hours. After the holding time is completed, allow it to cool with the furnace.

[0113] 10. After the sintering process is completed and the furnace temperature has cooled to 320°C, remove the sintered material and place it in room temperature water to cool for 30 minutes.

[0114] 11. After cooling, the sintered material is removed from the water to obtain the polytetrafluoroethylene composite material of Comparative Example 2.

[0115] Comparative Example 3

[0116] 1. Mix 3g of carbon fiber powder with 30g of sulfuric acid under mechanical stirring to ensure that the carbon fiber and sulfuric acid solvent are in full contact.

[0117] 2. Heat the mixture of carbon fiber and sulfuric acid from step 1 to 80°C and heat for 30 minutes with stirring.

[0118] 3. After step 2 is completed, pour the mixed solution into ice water and then into the suction filter. Wash the carbon fiber several times to bring the pH to around 7, and then dry it for later use.

[0119] 4. Dissolve 0.9g of tridecafluorooctyltrimethoxysilane in 17.1g of ethanol. After the silane is dispersed, completely disperse the acidified carbon fiber dried in step 3 in the ethanol mixture. Stir the ethanol mixture and heat it to 80°C and maintain it for 60 minutes.

[0120] 5. After step 4 is completed, the carbon fiber powder is filtered, washed, and dried for later use to obtain modified carbon fiber.

[0121] 6. Mix 12g of polytetrafluoroethylene powder and the modified carbon fiber obtained in step 5 thoroughly in a high-speed mixer.

[0122] 7. Slowly add the mixture into a cold-pressing mold with a magnetic field strength of 3000Gs.

[0123] 8. Place the mold in a pressure device and apply 80MPa pressure to the mixture using a cold pressing method. Maintain the pressure for 30 minutes to solidify it and form a green compact.

[0124] 9. After the molding process is completed, remove the green billet from the mold and place it in the sintering furnace. Set the sintering temperature of the sintering furnace to 370℃ and the holding time to 2 hours. After the holding time is completed, allow it to cool with the furnace.

[0125] 10. After the sintering process is completed and the furnace temperature has cooled to 320°C, remove the sintered material and place it in room temperature water to cool for 30 minutes.

[0126] 11. After cooling, the sintered material is removed from the water to obtain the polytetrafluoroethylene composite material of Comparative Example 3.

[0127] Comparative Example 4

[0128] 1. Mix 3g of carbon fiber powder with 30g of sulfuric acid under mechanical stirring to ensure that the carbon fiber and sulfuric acid solvent are in full contact.

[0129] 2. Heat the mixture of carbon fiber and sulfuric acid from step 1 to 80°C and heat for 30 minutes with stirring.

[0130] 3. After step 2 is completed, pour the mixed solution into ice water and then into the suction filter. Wash the carbon fiber several times to bring the pH to around 7, and then dry it for later use.

[0131] 4. Dissolve 0.9g of tridecafluorooctyltrimethoxysilane in 17.1g of ethanol. After the silane is dispersed, completely disperse the acidified carbon fiber dried in step 3 in the ethanol mixture. Stir the ethanol mixture and heat it to 80°C and maintain it for 60 minutes.

[0132] 5. After step 4 is completed, the carbon fiber powder is filtered, washed, and dried for later use to obtain modified carbon fiber.

[0133] 6. Mix 12g of polytetrafluoroethylene powder and the modified carbon fiber obtained in step 5 thoroughly in a high-speed mixer.

[0134] 7. Slowly add the mixture into a cold-pressing mold with a magnetic field strength of 3000Gs.

[0135] 8. Place the mold in a pressure device and apply 80MPa pressure to the mixture using a cold pressing method. Maintain the pressure for 30 minutes to solidify it and form a green compact.

[0136] 9. After the molding process is completed, remove the green billet from the mold and place it in the sintering furnace. Set the sintering temperature of the sintering furnace to 370℃ and the holding time to 2 hours. After the holding time is completed, allow it to cool with the furnace.

[0137] 10. After the sintering process is completed and the furnace temperature has cooled to 320°C, remove the sintered material and place it in room temperature water with a magnetic field strength of 4000 Gs to magnetize it and cool it for 30 minutes.

[0138] 11. After cooling, the sintered material is removed from the water to obtain the polytetrafluoroethylene composite material of Comparative Example 4.

[0139] Comparative Example 5

[0140] 1. Mix 3g of carbon fiber powder with 30g of sulfuric acid under mechanical stirring to ensure that the carbon fiber and sulfuric acid solvent are in full contact.

[0141] 2. Heat the mixture of carbon fiber and sulfuric acid from step 1 to 80°C and heat for 30 minutes with stirring.

[0142] 3. After step 2 is completed, pour the mixed solution into ice water and then into the suction filter. Wash the carbon fiber several times to bring the pH to around 7, and then dry it for later use.

[0143] 4. Dissolve 0.9g of tridecafluorooctyltrimethoxysilane in 17.1g of ethanol. After the silane is dispersed, completely disperse the acidified carbon fiber dried in step 3 in the ethanol mixture. Stir the ethanol mixture and heat it to 80°C and maintain it for 60 minutes.

[0144] 5. After step 4 is completed, the carbon fiber powder is filtered, washed, and dried for later use to obtain grafted modified carbon fiber.

[0145] 6. Mix 12g of polytetrafluoroethylene powder and the grafted modified carbon fiber obtained in step 5 thoroughly in a high-speed mixer.

[0146] 7. Slowly add the mixture into the special cold-pressing mold.

[0147] 8. Place the mold in a pressure device and apply 80MPa pressure to the mixture using a cold pressing method. Maintain the pressure for 30 minutes to solidify it and form a green compact.

[0148] 9. After the molding process is completed, remove the green billet from the mold and place it in the sintering furnace. Set the sintering temperature of the sintering furnace to 370℃ and the holding time to 2 hours. After the holding time is completed, allow it to cool with the furnace.

[0149] 10. After the sintering process is completed and the furnace temperature has cooled to 320°C, remove the sintered material and place it in room temperature water to cool for 30 minutes.

[0150] 11. After cooling, the sintered material is removed from the water to obtain the filler-reinforced polytetrafluoroethylene composite material.

[0151] Friction and wear tests were conducted on the composite materials prepared in each embodiment and comparative example using a friction and wear testing machine. Simultaneously, a white light interferometer was used to characterize and measure the material wear tracks and wear rates. Furthermore, the compressive strength of the materials was tested using a universal tensile testing machine (based on 25% compression deformation). The results are shown in Table 1 and... Figures 4 to 6 As shown. Among them, Figure 6 The image at point a is a white light image of the abrasion marks from Example 1. Figure 6 The image at point b is a white light image of the abrasion mark from Comparative Example 5.

[0152] Table 1

[0153]

[0154] from Figure 4It can be seen that the material after thermomagnetization exhibits higher compressive strength, with an 82.35% increase in compressive strength at 25% compression compared to Comparative Example 5. The composite material treated with thermomagnetization also shows a more stable friction curve and a lower wear rate. In Comparative Example 5, due to poor bonding between the reinforcing filler and the substrate, as well as poor unidirectionality, the filler was prone to peeling and appeared at the friction interface, resulting in poor wear resistance and large fluctuations in the friction curve. Compared to Comparative Example 5, the composite material prepared by thermomagnetization showed a 56.29% reduction in wear rate and a more stable friction coefficient curve. The conclusion indicates that thermomagnetization has a significant impact on filler-reinforced composite materials, and whether or not the filler modification process involves magnetization has the greatest impact on the test results. The polytetrafluoroethylene (PTFE) molded using the process described in this application exhibits higher compressive strength and a lower wear rate, providing a basis for the research and application of high-strength sealing materials.

[0155] Compared to traditional solvent modification techniques, this invention employs a thermomagnetization process to alter the dipole moment of the corrosive solution and the grafting agent, refining the molecular size and increasing reactivity while lowering the interfacial reaction threshold, thus enhancing the material modification effect and improving the bonding ability between the filler and the matrix. Simultaneously, it further promotes the directional distribution of the filler in the composite material, resulting in higher strength and wear resistance. The fluorinated composite material prepared by this invention exhibits high compressive strength and high wear resistance, effectively meeting the requirements of high-speed oil seals under complex operating conditions.

[0156] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0157] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A process for the preparation of a high-strength thermally magnetically enhanced fluorine-containing composite material, characterized in that, The method comprises the following steps: eroding the filler with the etching solution under the heating and magnetic field environment, filtering and drying to obtain the magnetized etching filler; mixing the sizing grafting agent with the magnetized etching filler to modify the magnetized etching filler with the polar molecules of the sizing grafting agent under the heating and magnetic field environment, filtering and drying to obtain the magnetized modified filler; mixing the fluorine-containing resin powder with the magnetized modified filler, and molding into a green body in a mold located in a magnetic field to obtain the magnetized filler modified green body; sintering the magnetized filler modified green body, taking out and cooling in water located in a magnetic field when the temperature drops to the solidification temperature to obtain the high-strength thermomagnetic enhanced fluorine-containing composite material.

2. The method of claim 1, wherein the high-strength thermally magnetically enhanced fluorocomposite is prepared by the steps of: The filler is at least one of carbon fiber, glass fiber, graphite, molybdenum disulfide, silicon dioxide, titanium dioxide, silicon carbide, silicon nitride, potassium titanate whisker and carbon nanotube whisker.

3. The method of claim 2, wherein the high-strength thermally magnetically enhanced fluorocomposite is prepared by the steps of: The etching solution is at least one of sulfuric acid, nitric acid, hydrochloric acid, 5-10% sodium hydroxide, 5-10% potassium hydroxide, hydrofluoric acid, phosphoric acid, peroxodisulfuric acid and permanganic acid.

4. The method of claim 3, wherein the high-strength thermally magnetically enhanced fluorocomposite is prepared by the steps of: In the step of eroding the filler with the etching solution under the heating and magnetic field environment, the mass ratio of the etching solution to the filler is 10:1, the heating temperature is 50-80°C, the magnetic field strength is 3000-6000Gs, and the treatment time is 30-60 minutes.

5. The method of claim 1 wherein the high-strength thermally magnetically enhanced fluorocomposite material is characterized by, The solute of the sizing grafting agent is at least one of aminopropyl triethoxysilane, aminopropyl trimethylsilane, γ-(2,3-epoxypropoxy) propyl trimethoxysilane, methacryloyl silane, vinyl triethoxysilane, vinyl tri(2-methoxyethoxy)silane, γ-mercaptopropyl trimethoxysilane, tridecafluoro octyl triethoxysilane, perfluoropolyether siloxane and tridecafluoro octyl trimethoxysilane.

6. The method of claim 5, wherein the high-strength thermally magnetically enhanced fluorocomposite is prepared by the steps of: The mass concentration of the sizing grafting agent is 5%, and the mass ratio of the magnetized etching filler to the sizing grafting agent is 1:

6.

7. The method of claim 1, wherein the high-strength thermally magnetically enhanced fluorocomposite material is characterized by, In the step of mixing the sizing grafting agent with the magnetized etching filler under the heating and magnetic field environment, the temperature is first raised to 50°C at a rate of 5°C / min under a magnetic field of 5000Gs, and then the temperature is raised to 80°C at a rate of 2°C / min under a magnetic field of 13000Gs, and finally the magnetic field is removed.

8. The method of claim 1, wherein the high-strength thermally magnetically enhanced fluorocomposite material is characterized by, In the step of mixing the fluorine-containing resin powder with the magnetized modified filler and molding into a green body in a mold located in a magnetic field, the magnetic field strength is 3000-6000Gs, the mass ratio of the fluorine-containing resin powder to the magnetized modified filler is 4:1, the cavity of the mold is a hollow column, and the magnetic pole connecting line of the magnetic field coincides with the axis of the cavity.

9. The method of claim 1 wherein the high-strength thermally magnetically enhanced fluorocomposite material is characterized by, In the step of taking out and cooling in water located in a magnetic field, the magnetic field strength is 4000Gs, and the time is 30-50 minutes.

10. A high-strength thermally magnetically enhanced fluorine-containing composite material, characterized by, The high-strength thermomagnetic enhanced fluorine-containing composite material is prepared by the method of any one of claims 1-9.

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