Heat-resistant high-elasticity polytetrafluoroethylene sealing ring and preparation method thereof

Abstract

The invention discloses a heat-resistant high-elasticity polytetrafluoroethylene sealing ring and a preparation method thereof, and relates to the field of polytetrafluoroethylene sealing rings, the heat-resistant high-elasticity polytetrafluoroethylene sealing ring comprises the following raw materials by weight: 65-75 parts of activated PTFE resin, 5-10 parts of polyimide, 1.5-2 parts of modified copper nanoparticles, 3-5 parts of modified glass fiber, 0.2-0.4 part of a coupling agent, and 0.5-0.7 part of a dispersant. And the modified copper nanoparticles are not easy to agglomerate, so that the oxidation resistance is improved, and the heat resistance and mechanical strength of the sealing ring can be remarkably enhanced. The toughness of the modified glass fiber and the interface bonding force with the polytetrafluoroethylene resin are enhanced, and the elasticity of the sealing ring is improved.

Description

Technical Field

[0001] The invention relates to the field of polytetrafluoroethylene sealing rings, and in particular to a heat-resistant high-elastic polytetrafluoroethylene sealing ring and a preparation method thereof. Background Art

[0002] Polytetrafluoroethylene is a kind of engineering plastics. The molecular polarity of polytetrafluoroethylene is very small, and it is a completely symmetrical, unbranched linear polymer. Polytetrafluoroethylene resin has the advantages of excellent self-lubrication, non-stickiness, non-flammability, insulation, chemical stability and a wide applicable temperature range (-190℃-260℃). It is widely used in the fields of anti-corrosion and anti-sticking, friction reduction and lubrication, and sealing and leak prevention in industrial production.

[0003] In order to make up for the shortcomings of the poor wear resistance of polytetrafluoroethylene composite materials, filling modification is usually used, and the principle of complementary advantages is used to make the modified polytetrafluoroethylene composite materials have excellent comprehensive properties. Commonly used metal fillers for modified polytetrafluoroethylene include copper, lead, zinc, tungsten and their oxide fillers. Previously, studies have used polytetrafluoroethylene, polyimide, and copper nanoparticles to blend to obtain polytetrafluoroethylene composite materials with significantly improved self-lubricity and wear resistance. However, the self-agglomeration of copper nanoparticles leads to poor uniform dispersion with polytetrafluoroethylene and polyimide, resulting in poor mechanical properties of polytetrafluoroethylene composite materials, which urgently need to be improved. In addition, the high activity of the surface of copper nanoparticles causes them to be oxidized in the air, and the proximity of water will lead to increased oxidation. Commonly used benzotriazole substances form an adsorption film on the surface of copper nanoparticles, which has a good effect on the antioxidant properties of copper powder at room temperature, but is not suitable for antioxidant properties at high temperatures.

[0004] Common fibrous fillers for modified polytetrafluoroethylene include glass fiber, carbon fiber, etc. Previous studies have used glass fiber to improve the creep resistance and elasticity of polytetrafluoroethylene materials. However, the interfacial bonding between glass fiber and polytetrafluoroethylene is poor, and the toughness of glass fiber is poor, which causes the composite material formed by polytetrafluoroethylene / glass fiber to be prone to brittle cracking under dynamic compression-rebound conditions, which is not conducive to improving the elasticity of the composite material and limits the use of glass fiber in polytetrafluoroethylene composite materials.

[0005] Therefore, the present invention provides a modification method to improve the agglomeration, high temperature oxidation resistance and water oxidation resistance of copper nanoparticles, enhance the toughness of glass fiber and the interfacial bonding strength with polytetrafluoroethylene resin, so as to obtain a polytetrafluoroethylene sealing ring material with better comprehensive properties such as heat resistance and elasticity. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a heat-resistant and highly elastic polytetrafluoroethylene sealing ring and a preparation method thereof.

[0007] The object of the present invention can be achieved by the following technical solutions: A heat-resistant high-elasticity polytetrafluoroethylene sealing ring, comprising the following raw materials in parts by weight: 65-75 parts of activated PTFE resin, 5-10 parts of polyimide, 1.5-2 parts of modified copper nanoparticles, 3-5 parts of modified glass fiber, 0.2-0.4 part of coupling agent, and 0.5-0.7 part of dispersant; Further, the coupling agent is KH550; the dispersant is polyvinylpyrrolidone; Further, the preparation method of the activated PTFE resin is as follows: in an inert gas atmosphere, soak the polytetrafluoroethylene resin in a naphthalene sodium treatment solution for 8-10 min, take it out and then soak it in acetone for 5-7 min, and then wash it with deionized water and dry it to obtain the activated PTFE resin; The preparation of the heat-resistant high-elasticity polytetrafluoroethylene sealing ring comprises the following steps: Stir the activated PTFE resin, polyimide, modified copper nanoparticles, modified glass fiber, coupling agent, and dispersant at a high speed to obtain a mixture, press the mixture into a blank, and let it stand in a drying oven, and then heat it up and keep it warm in an inert gas atmosphere, and then turn it and grind it to make a sealing ring, and then perform annealing treatment to obtain the heat-resistant high-elasticity polytetrafluoroethylene sealing ring; Further, the preparation of the heat-resistant high-elasticity polytetrafluoroethylene sealing ring comprises the following specific steps: Stir the activated PTFE resin, polyimide, modified copper nanoparticles, modified glass fiber, coupling agent, and dispersant at a speed of 800-1000 rpm for 10-15 min to obtain a mixture, press the mixture at 20-30 MPa for 40-50 min to form a blank, and let it stand in a drying oven at 25-30 °C for 24-25 h, and then heat it up to 370-380 °C at a rate of 100 °C / h in an inert gas atmosphere and keep it warm for 4-4.5 h, and then turn it and grind it to make a sealing ring, and then perform annealing treatment at 120-130 °C for 1.5-2 h to obtain the heat-resistant high-elasticity polytetrafluoroethylene sealing ring; The preparation of the modified copper nanoparticles comprises the following steps: Step A1: Mix and react the carbaborane carboxylic acid with thionyl dichloride to obtain product c1; drop the dispersion liquid b containing product c1 into the dispersion liquid a containing nitrobenzotriazole, and stir and react to obtain product c2; Step A2: Reduce product c2 with a reducing agent to obtain product c3; react the nitrogen-containing adamantane with epichlorohydrin under the action of a catalyst, cool and add an alkali solution, and react to obtain product c4; mix and stir product c3, product c4, and DMAC to obtain product c5; Step A3: Hydrolyze silane in a mixed solvent to obtain a hydrolysis solution; treat nano copper powder with an acid solution to obtain pretreated copper powder; mix and react the pretreated copper powder, the hydrolysis solution, and xylene to obtain product c6; Step A4: Mix product c5, tetrahydrofuran, ethanol, potassium carbonate, and product c6, stir, and then add triethylamine, and react to obtain modified copper nanoparticles; Furthermore, the preparation of the modified copper nanoparticles includes the following specific steps: Step A1: Mix carborane carboxylic acid, NMP, and thionyl chloride, and stir and react at 55 - 65 °C for 4 - 4.5 h to obtain product c1; add nitrobenzotriazole and sodium hydroxide to tetrahydrofuran and stir to obtain dispersion liquid a; add product c1 to tetrahydrofuran and stir to obtain dispersion liquid b; drop dispersion liquid b into dispersion liquid a under an ice - water bath, and then stir and react at 40 - 45 °C for 6 - 6.5 h to obtain product c2; Furthermore, the dosage ratio of carborane carboxylic acid, NMP, and thionyl chloride is 20 - 22 g : 70 - 80 mL : 12 - 14 g, and the carborane carboxylic acid is o - carborane acetic acid; the dosage ratio of nitrobenzotriazole, sodium hydroxide, and tetrahydrofuran in dispersion liquid a is 17 - 19 g : 1 - 2 g : 40 - 50 mL, and the nitrobenzotriazole is 4 - nitro - 1H - 1,2,3 - benzotriazole; the dosage ratio of product c1 and tetrahydrofuran in dispersion liquid b is 24 - 26 g : 55 - 65 mL; the dosage ratio of dispersion liquid b and dispersion liquid a is 75 - 85 mL : 65 - 75 mL; During the reaction process of Step A1, the carborane carboxylic acid reacts with thionyl chloride to obtain a carborane - containing acyl chloride product, which is product c1; the acyl chloride of product c1 reacts with the secondary amine in nitrobenzotriazole to obtain product c2 containing carborane, nitro, benzotriazole, and imide; Step A2: Add product c2 to toluene, add potassium bicarbonate and a reducing agent at 45 - 55 °C, stir and react for 2 - 2.5 h to obtain product c3; mix nitrogen - containing adamantane, epichlorohydrin, a catalyst, and toluene, stir and react at 100 - 105 °C for 4 - 4.5 h, cool, add an alkali solution, and continue to stir for 5 - 5.5 h to obtain product c4; mix product c3, product c4, and DMAC, and stir and react at 70 - 80 °C for 8 - 8.5 h to obtain product c5; Further, the dosage ratio of product c2, toluene, potassium bicarbonate, and reducing agent is 44 - 46 g : 140 - 150 mL : 3.5 - 4.5 g : 20 - 22 g, and the reducing agent is sodium dithionite; the dosage ratio of nitrogen-containing adamantane, epichlorohydrin, catalyst, toluene, and alkali solution is 16 - 18 g : 20 - 22 g : 3 - 5 g : 85 - 95 mL : 10 - 15 mL, the nitrogen-containing adamantane is 7-amino-1,3,5-triazaadamantane, the alkali solution is a potassium hydroxide solution with a mass fraction of 30 - 40%, and the catalyst is tetrabutylammonium chloride; the dosage ratio of product c3, product c4, and DMAC is 43 - 45 g : 48 - 50 g : 185 - 195 mL; During the reaction process of step A2, the nitro group of product c2 is reduced to an amino group, obtaining product c3 containing carborane, amino group, benzotriazole, and imide; the amino group of nitrogen-containing adamantane reacts with epichlorohydrin to obtain nitrogen-containing adamantane containing an epoxy group, which is product c4; the amino group of product c3 reacts with the epoxy group of product c4 to obtain product c5 containing carborane, benzotriazole, imide, nitrogen-containing adamantane, and hydroxyl group; Step A3: Mix silane and a mixed solvent, adjust the pH to 4 - 5, stir at 50 - 60 °C for 1 - 1.5 h to obtain a hydrolysis solution; mix nano copper powder and acid solution, ultrasonically oscillate for 30 - 35 min, wash with deionized water until neutral, and vacuum dry to obtain pretreated copper powder; in an atmosphere of protective gas, add the pretreated copper powder to the hydrolysis solution, then add xylene, stir at 80 - 90 °C for 2 - 2.5 h, wash successively with ethanol and acetone, and vacuum dry at 60 - 70 °C for 12 - 13 h to obtain product c6; Further, the dosage ratio of silane and the mixed solvent in the hydrolysis solution is 26 - 28 g : 60 - 70 mL, the silane is bromobutyltrimethoxysilane, and the mixed solvent is a mixture of absolute ethanol and deionized water in a volume ratio of 4:1; the dosage ratio of nano copper powder and acid solution is 1 - 2 g : 5 - 10 mL, and the acid solution is a sulfuric acid solution with a mass fraction of 15 - 20%; the dosage ratio of pretreated copper powder, hydrolysis solution, and xylene is 5 - 7 g : 90 - 100 mL : 80 - 90 mL; the volume fraction of ethanol is 95%; During the reaction process of step A3, the silanol obtained by the hydrolysis of silane modifies the nano copper powder whose surface oxide layer has been removed by acid solution treatment to obtain product c6; Step A4: Mix product c5, tetrahydrofuran, and ethanol, add potassium carbonate under stirring, then add product c6, reflux and stir at 90 - 100 °C for 3 - 3.5 h, and then add triethylamine and continue stirring for 2 - 2.5 h to obtain modified copper nanoparticles; Further, the dosage ratio of product c5, tetrahydrofuran, ethanol, potassium carbonate, and triethylamine is 93 - 95 g : 150 - 160 mL : 50 - 60 mL : 3 - 5 g : 21 - 23 g; During the reaction of step A4, the hydroxyl group of product c5 and the alkyl bromide of product c6 eliminate hydrogen bromide to obtain a product grafted with carborane, nitrogen-containing adamantane, benzotriazole and nano-copper powder, which is the modified copper nanoparticles; The preparation of the modified glass fiber includes the following steps: Step B1: Add glass fiber into acetone for pretreatment to obtain pretreated glass fiber; in an atmosphere of protective gas, mix the pretreated glass fiber, isocyanate, xylene and stannous octoate for reaction, then add phosphoric acid, stir and perform post-treatment to obtain product d1; Step B2: Reduce product d1 with sodium dithionite to obtain product d2; react terminal hydroxyl ether and epichlorohydrin under alkaline conditions to obtain product d3; mix product d2, product d3 and DMSO for reaction to obtain product d4; Step B3: Mix nitroacyl chloride and DMSO to obtain mixture 1; react product d4 with nitroacyl chloride in mixture 1 to obtain product d5; mix product d5 and mixed solvent 1, and obtain product d6 under the action of sodium dithionite; in an atmosphere of protective gas, mix product d6 and triphosgene for reaction to obtain the modified glass fiber; Furthermore, the preparation of the modified glass fiber includes the following specific steps: Step B1: Add glass fiber into acetone, ultrasonically disperse for 25 - 35 min, take it out and wash it with deionized water until neutral, then vacuum dry at 70 - 80 °C for 6 - 7 h to obtain pretreated glass fiber; in an atmosphere of protective gas, mix the pretreated glass fiber, isocyanate, xylene and stannous octoate, stir and react at 60 - 70 °C for 3 - 4 h, add phosphoric acid and continue to stir for 5 - 10 min, filter by suction and wash it three times with ethanol and acetone successively, then dry at 50 - 60 °C for 7 - 8 h to obtain product d1; Furthermore, the dosage ratio of glass fiber to acetone is 5 - 6 g : 90 - 100 mL; the dosage ratio of pretreated glass fiber, isocyanate, xylene, stannous octoate and phosphoric acid is 6 - 10 g : 10 - 15 g : 110 - 120 mL : 0.025 - 0.035 g : 0.15 - 0.25 g, the isocyanate is 2 - fluoro - 5 - isocyanatonitrobenzene, and the volume fraction of ethanol is 95%; During the reaction of step B1, the grease and impurities on the surface of the glass fiber are removed to obtain pretreated glass fiber, and the surface of the pretreated glass fiber is modified with isocyanate to obtain glass fiber with fluorine and nitro groups on the surface, which is product d1; Step B2: Mix the product d1 and toluene, add sodium dithionite under stirring at 40 - 50 °C, and stir and react for 2 - 2.5 h to obtain the product d2; Mix the terminal hydroxyl ether, toluene, and alkali solution 1 under stirring for 8 - 10 min, add epichlorohydrin, and stir and react at room temperature for 5 - 5.5 h to obtain the product d3; Mix the product d2, the product d3, and DMSO, and stir and react at 50 - 60 °C for 24 - 25 h to obtain the product d4; Further, the dosage ratio of the product d1, toluene, and sodium dithionite is 8 - 10 g : 150 - 160 mL : 4 - 5 g; the dosage ratio of the terminal hydroxyl ether, toluene, alkali solution 1, and epichlorohydrin is 48 - 50 g : 130 - 140 mL : 3 - 5 mL : 10 - 12 g, the alkali solution 1 is a potassium hydroxide solution with a mass fraction of 10 - 15%, and the terminal hydroxyl ether is polyoxyethylene cetyl (5) ether; the dosage ratio of the product d2, the product d3, and DMSO is 7 - 9 g : 60 - 62 g : 140 - 150 mL; During the reaction process of Step B2, the nitro group of the product d1 is reduced to an amino group to obtain the product d2; the terminal hydroxyl group of the terminal hydroxyl ether reacts with epichlorohydrin to obtain the product d3 containing an ether long chain, an alkane long chain, and an epoxy group; the amino group of the product d2 reacts with the epoxy group of the product d3 to obtain glass fibers with fluorine, hydroxyl, ether long chain, and alkane long chain on the surface, that is, the product d4; Step B3: Mix the nitrobenzoyl chloride and DMSO to obtain the mixed solution 1; After mixing the product d4, isoquinoline, triethylamine, and DMSO, add the mixed solution 1 in an ice - water bath, and after adding, stir and react at 40 - 50 °C for 8 - 8.5 h to obtain the product d5; Add the product d5 into the mixed solvent 1, add sodium dithionite under stirring at 55 - 65 °C, and stir and react for 2 - 2.5 h to obtain the product d6; In an inert gas atmosphere, mix the product d6, tetrahydrofuran, and toluene, add triphosgene at 65 - 75 °C, stir and react for 1 - 1.5 h, then raise the temperature to 115 - 125 °C, and stir and react for 2 - 2.5 h to obtain the modified glass fibers; Further, the dosage ratio of the nitrobenzoyl chloride and DMSO in the mixed solution 1 is 19 - 21 g : 40 - 50 mL, and the nitrobenzoyl chloride is p - nitrobenzoyl chloride; the dosage ratio of the product d4, isoquinoline, triethylamine, DMSO, and the mixed solution 1 is 15 - 20 g : 1.5 - 2 g : 13 - 15 g : 125 - 135 mL : 65 - 70 mL; the dosage ratio of the product d5, the mixed solvent 1, and sodium dithionite is 18 - 22 g : 190 - 200 mL : 22 - 26 g, and the mixed solvent 1 is a mixture of methanol and tetrahydrofuran in a volume ratio of 3:2; the dosage ratio of the product d6, tetrahydrofuran, toluene, and triphosgene is 16 - 18 g : 60 - 70 mL : 110 - 120 mL : 12 - 16 g; During the reaction process of step B3, the nitroacyl chloride reacts with the hydroxyl group of product d4 to obtain glass fibers with fluorine, nitro, ether long chains, and alkane long chains on the surface, namely product d5; the nitro group of product d5 is reduced to an amino group to obtain product d6; the amino group of product d6 reacts with triphosgene to form chloroamide, and then dehydrochlorination is carried out by heating to generate isocyanate, obtaining glass fibers with fluorine, ether long chains, alkane long chains, and isocyanate on the surface, namely the modified glass fibers. The beneficial effects of the present invention: The present invention discloses a heat-resistant high-elastic polytetrafluoroethylene sealing ring and a preparation method thereof. The polytetrafluoroethylene sealing ring comprises raw materials such as activated PTFE resin, polyimide, modified copper nanoparticles, modified glass fibers, coupling agent, and dispersant.

[0008] The modified copper nanoparticles are obtained by grafting nano-copper powder through reactions with o-carborane acetic acid, 4-nitro-1H-1,2,3-benzotriazole, 7-amino-1,3,5-triazaadamantane, etc.; after the reaction combination of o-carborane acetic acid and 7-amino-1,3,5-triazaadamantane, through the synergistic effect of the cage-like rigid skeleton and the highly symmetric nitrogen-substituted rigid ring, the deficiency of the high-temperature antioxidant effect of benzotriazole on nano-copper powder is significantly compensated; after the reaction combination of 4-nitro-1H-1,2,3-benzotriazole and 7-amino-1,3,5-triazaadamantane, a stable adsorption film is formed on the surface of the nano-copper powder synergistically, further enhancing the high-temperature antioxidant property; after the reaction combination of o-carborane acetic acid and 7-amino-1,3,5-triazaadamantane, through the synergistic hydrophobic effect of carborane and nitrogen-containing adamantane, the enhanced oxidation effect of copper nanoparticles caused by water is avoided; after the reaction combination of o-carborane acetic acid and 4-nitro-1H-1,2,3-benzotriazole, imide is introduced into the modified copper nanoparticles, enhancing the compatibility between the modified copper nanoparticles and polyimide, improving the agglomeration phenomenon of the modified copper nanoparticles, and compensating for the decrease in the mechanical strength of the sealing ring caused by the agglomeration of copper nanoparticles. The modified copper nanoparticles can significantly improve the heat resistance and mechanical strength of the polytetrafluoroethylene sealing ring.

[0009] The modified glass fiber is obtained by modifying the surface of glass fiber with 2-fluoro-5-isocyanatonitrobenzene and then reacting with polyoxyethylene cetyl (5) ether, p-nitrobenzoyl chloride, etc.; by using polyoxyethylene cetyl (5) ether and taking advantage of the flexibility of its ether long chain and alkane long chain, the toughness of the modified glass fiber is synergistically improved, making up for the deficiency that the glass fiber is prone to brittle cracking under dynamic compression-rebound conditions during the process of improving the creep resistance and elasticity of the sealing ring, thereby obtaining a polytetrafluoroethylene sealing ring with high elasticity; by using p-nitrobenzoyl chloride to participate in the reaction and converting the nitro group into an isocyanate group, the modified glass fiber can be bonded to oxygen-containing functional groups such as hydroxyl groups and carboxyl groups on the surface of the activated polytetrafluoroethylene resin through the isocyanate group, enhancing the interfacial bonding force between the activated polytetrafluoroethylene resin and the modified glass fiber, avoiding interfacial debonding, slowing down the wear and leakage of the sealing ring, and also contributing to the improvement of the elasticity of the sealing ring; the combined use of 2-fluoro-5-isocyanatonitrobenzene and polyoxyethylene cetyl (5) ether also enhances the compatibility between the modified glass fiber and the modified copper nanoparticles containing carborane and adamantane on the surface due to the hydrophobic fluorine and alkane long chain. Detailed implementation mode

[0010] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0011] Example 1 The preparation of a kind of the modified copper nanoparticles includes the following specific steps: Step A1: Mix o-carborane acetic acid, NMP, and thionyl chloride, and stir and react at 55 °C for 4 h to obtain product c1; add 4-nitro-1H-1,2,3-benzotriazole and sodium hydroxide to tetrahydrofuran and stir to obtain dispersion a; add product c1 to tetrahydrofuran and stir to obtain dispersion b; drop dispersion b into dispersion a under an ice-water bath, and then stir and react at 40 °C for 6 h to obtain product c2; the dosage ratio of o-carborane acetic acid, NMP, and thionyl chloride is 20 g: 70 mL: 12 g; the dosage ratio of 4-nitro-1H-1,2,3-benzotriazole, sodium hydroxide, and tetrahydrofuran in dispersion a is 17 g: 1 g: 40 mL; the dosage ratio of product c1 and tetrahydrofuran in dispersion b is 24 g: 55 mL; the dosage ratio of dispersion b and dispersion a is 75 mL: 65 mL; Step A2, adding product c2 to toluene, adding potassium bicarbonate and sodium dithionite at 45°C, stirring and reacting for 2h to obtain product c3; mixing 7-amino-1,3,5-triazaadamantane, epichlorohydrin, tetrabutylammonium chloride and toluene, stirring and reacting at 100°C for 4h, adding alkali solution after cooling, and continuing stirring for 5h to obtain product c4; mixing product c3, product c4 and DMAC, stirring and reacting at 70°C for 8h to obtain product c 5; the dosage ratio of product c2, toluene, potassium bicarbonate, and sodium dithionite is 44g:140mL:3.5g:20g; the dosage ratio of 7-amino-1,3,5-triazaadamantane, epichlorohydrin, tetrabutylammonium chloride, toluene, and alkali solution is 16g:20g:3g:85mL:10mL, and the alkali solution is a potassium hydroxide solution with a mass fraction of 30%; the dosage ratio of product c3, product c4, and DMAC is 43g:48g:185mL; Step A3, bromobutyltrimethoxysilane and a mixed solvent were mixed, the pH was adjusted to 4.2, and the mixture was stirred at 50°C for 1 hour to obtain a hydrolyzate; nano copper powder (supplier: Xi'an Qiyue Biotechnology Co., Ltd.) and an acid solution were mixed and ultrasonically oscillated for 30 minutes, washed with deionized water until neutral, and vacuum dried at 80°C for 8 hours to obtain a pretreated copper powder; in a nitrogen atmosphere, the pretreated copper powder was added to the hydrolyzate, and then xylene was added, stirred at 80°C for 2 hours, and washed with ethanol and acetone in turn. The product c6 was obtained by washing and vacuum drying at 60°C for 12h. The amount ratio of bromobutyltrimethoxysilane and the mixed solvent in the hydrolyzate was 26g:60mL, and the mixed solvent was obtained by mixing anhydrous ethanol and deionized water in a volume ratio of 4:1. The amount ratio of nano copper powder and acid solution was 1g:5mL, and the acid solution was a sulfuric acid solution with a mass fraction of 15%. The amount ratio of pretreated copper powder, hydrolyzate and xylene was 5g:90mL:80mL. The volume fraction of ethanol was 95%. Step A4, add potassium carbonate to the product c5, tetrahydrofuran and ethanol while stirring, then add the product c6, reflux and stir at 90°C for 3 hours, then add triethylamine and continue stirring for 2 hours to obtain modified copper nanoparticles; the amount ratio of product c5, tetrahydrofuran, ethanol, potassium carbonate and triethylamine is 93g:150mL:50mL:3g:21g.

[0012] Example 2 A preparation method of the modified copper nanoparticles includes the following specific steps: Step A1, o-borane acetic acid, NMP, and dichlorothionyl are mixed, and the mixture is stirred at 60° C. for 4.3 h to obtain product c1; 4-nitro-1H-1,2,3-benzotriazole and sodium hydroxide are added to tetrahydrofuran and stirred to obtain dispersion a; product c1 is added to tetrahydrofuran and stirred to obtain dispersion b; dispersion b is added dropwise to dispersion a under an ice-water bath, and the mixture is stirred at 43° C. for 6.3 h to obtain product c2; the dosage ratio of o-borane acetic acid, NMP, and dichlorothionyl is 21 g:75 mL:13 g; the dosage ratio of 4-nitro-1H-1,2,3-benzotriazole, sodium hydroxide, and tetrahydrofuran in dispersion a is 18 g:1.5 g:45 mL; the dosage ratio of product c1 and tetrahydrofuran in dispersion b is 25 g:60 mL; the dosage ratio of dispersion b to dispersion a is 80 mL:70 mL; Step A2, add product c2 to toluene, add potassium bicarbonate and sodium dithionite at 50°C, stir and react for 2.3 hours to obtain product c3; mix 7-amino-1,3,5-triazaadamantane, epichlorohydrin, tetrabutylammonium chloride and toluene, stir and react at 103°C for 4.3 hours, add alkali solution after cooling, and continue stirring for 5.3 hours to obtain product c4; mix product c3, product c4 and DMAC, stir and react at 75°C for 8.3 hours to obtain To product c5; the dosage ratio of product c2, toluene, potassium bicarbonate, and sodium dithionite is 45g:145mL:4.0g:21g; the dosage ratio of 7-amino-1,3,5-triazaadamantane, epichlorohydrin, tetrabutylammonium chloride, toluene, and alkali solution is 17g:21g:4g:90mL:13mL, and the alkali solution is a potassium hydroxide solution with a mass fraction of 35%; the dosage ratio of product c3, product c4, and DMAC is 44g:49g:190mL; Step A3, bromobutyltrimethoxysilane and a mixed solvent were mixed, the pH was adjusted to 4.5, and the mixture was stirred at 55°C for 1.3 hours to obtain a hydrolyzate; nano copper powder (supplier: Xi'an Qiyue Biotechnology Co., Ltd.) and an acid solution were mixed and ultrasonically oscillated for 33 minutes, washed with deionized water until neutral, and vacuum dried at 80°C for 8 hours to obtain a pretreated copper powder; in a nitrogen atmosphere, the pretreated copper powder was added to the hydrolyzate, and then xylene was added, stirred at 85°C for 2.3 hours, and washed with ethanol and acetone in turn. The product c6 was obtained by washing and vacuum drying at 65°C for 12.5h. The amount ratio of bromobutyltrimethoxysilane and the mixed solvent in the hydrolyzate was 27g:65mL, and the mixed solvent was obtained by mixing anhydrous ethanol and deionized water in a volume ratio of 4:1. The amount ratio of nano copper powder and acid solution was 1.5g:8mL, and the acid solution was a sulfuric acid solution with a mass fraction of 18%. The amount ratio of pretreated copper powder, hydrolyzate and xylene was 6g:95mL:85mL. The volume fraction of ethanol was 95%. Step A4: Mix product c5, tetrahydrofuran, and ethanol, add potassium carbonate under stirring, then add product c6, reflux and stir at 95 °C for 3.3 h, then add triethylamine and continue stirring for 2.3 h to obtain modified copper nanoparticles; the dosage ratio of product c5, tetrahydrofuran, ethanol, potassium carbonate, and triethylamine is 94 g: 155 mL: 55 mL: 4 g: 22 g.

[0013] Example 3 The preparation of the modified copper nanoparticles includes the following specific steps: Step A1: Mix o-carborane acetic acid, NMP, and thionyl chloride, stir and react at 65 °C for 4.5 h to obtain product c1; add 4-nitro-1H-1,2,3-benzotriazole and sodium hydroxide to tetrahydrofuran and stir to obtain dispersion a; add product c1 to tetrahydrofuran and stir to obtain dispersion b; add dispersion b dropwise to dispersion a under an ice-water bath, and then stir and react at 45 °C for 6.5 h to obtain product c2; the dosage ratio of o-carborane acetic acid, NMP, and thionyl chloride is 22 g: 80 mL: 14 g; the dosage ratio of 4-nitro-1H-1,2,3-benzotriazole, sodium hydroxide, and tetrahydrofuran in dispersion a is 19 g: 2 g: 50 mL; the dosage ratio of product c1 and tetrahydrofuran in dispersion b is 26 g: 65 mL; the dosage ratio of dispersion b and dispersion a is 85 mL: 75 mL; Step A2: Add product c2 to toluene, add potassium bicarbonate and sodium dithionite at 55 °C, stir and react for 2.5 h to obtain product c3; mix 7-amino-1,3,5-triazatricyclo[3.3.1.13,7]decane, epichlorohydrin, tetrabutylammonium chloride, and toluene, stir and react at 105 °C for 4.5 h, cool and add an alkali solution, and continue stirring for 5.5 h to obtain product c4; mix product c3, product c4, and DMAC, and stir and react at 80 °C for 8.5 h to obtain product c5; the dosage ratio of product c2, toluene, potassium bicarbonate, and sodium dithionite is 46 g: 150 mL: 4.5 g: 22 g; the dosage ratio of 7-amino-1,3,5-triazatricyclo[3.3.1.13,7]decane, epichlorohydrin, tetrabutylammonium chloride, toluene, and the alkali solution is 18 g: 22 g: 5 g: 95 mL: 15 mL, and the alkali solution is a potassium hydroxide solution with a mass fraction of 40%; the dosage ratio of product c3, product c4, and DMAC is 45 g: 50 g: 195 mL; Step A3, bromobutyltrimethoxysilane and a mixed solvent were mixed, the pH was adjusted to 4.7, and the mixture was stirred at 60°C for 1.5 hours to obtain a hydrolyzate; nano copper powder (supplier: Xi'an Qiyue Biotechnology Co., Ltd.) and an acid solution were mixed and ultrasonically oscillated for 35 minutes, washed with deionized water until neutral, and vacuum dried at 80°C for 8 hours to obtain a pretreated copper powder; in a nitrogen atmosphere, the pretreated copper powder was added to the hydrolyzate, and xylene was added, stirred at 90°C for 2.5 hours, and ethanol, acetone, and the like were used in sequence; Washing, vacuum drying at 70°C for 13h to obtain product c6; the amount ratio of bromobutyltrimethoxysilane and mixed solvent in the hydrolyzate is 28g:70mL, and the mixed solvent is anhydrous ethanol and deionized water mixed in a volume ratio of 4:1; the amount ratio of nano copper powder and acid solution is 2g:10mL, and the acid solution is a sulfuric acid solution with a mass fraction of 20%; the amount ratio of pretreated copper powder, hydrolyzate, and xylene is 7g:100mL:90mL; the volume fraction of ethanol is 95%; Step A4, add potassium carbonate to the product c5, tetrahydrofuran and ethanol while stirring, then add the product c6, reflux and stir at 100°C for 3.5 hours, then add triethylamine and continue stirring for 2.5 hours to obtain modified copper nanoparticles; the amount ratio of product c5, tetrahydrofuran, ethanol, potassium carbonate and triethylamine is 95g:160mL:60mL:5g:23g.

[0014] Example 4 A modified glass fiber, the preparation of which comprises the following steps: Step B1, add glass fiber (supplier: Tai'an Haosong Fiber Co., Ltd., model: bb-7) to acetone, ultrasonically disperse for 25 minutes, take out and wash with deionized water until neutral, vacuum dry at 70°C for 6 hours to obtain pretreated glass fiber; in a nitrogen atmosphere, mix the pretreated glass fiber, 2-fluoro-5-nitrobenzeneisocyanate, xylene, and stannous octoate, stir and react at 60°C for 3 hours, add phosphoric acid and continue stirring for 5 minutes, filter and wash with ethanol and acetone three times, dry at 50°C for 7 hours to obtain product d1; the amount ratio of glass fiber to acetone is 5g:90mL; the amount ratio of pretreated glass fiber, 2-fluoro-5-nitrobenzeneisocyanate, xylene, stannous octoate, and phosphoric acid is 6g:10g:110mL:0.025g:0.15g, and the volume fraction of ethanol is 95%; Step B2: Mix the product d1 and toluene, add sodium dithionite under stirring at 40°C, and stir and react for 2 h to obtain the product d2; mix polyoxyethylene cetyl (5) ether, toluene, and alkali solution 1 and stir for 8 min, add epichlorohydrin, and stir and react at room temperature for 5 h to obtain the product d3; mix the product d2, the product d3, and DMSO, and stir and react at 50°C for 24 h to obtain the product d4; the dosage ratio of the product d1, toluene, and sodium dithionite is 8 g: 150 mL: 4 g; the dosage ratio of polyoxyethylene cetyl (5) ether, toluene, alkali solution 1, and epichlorohydrin is 48 g: 130 mL: 3 mL: 10 g, and the alkali solution 1 is a potassium hydroxide solution with a mass fraction of 10%; the dosage ratio of the product d2, the product d3, and DMSO is 7 g: 60 g: 140 mL; Step B3: Mix p-nitrobenzoyl chloride and DMSO to obtain mixture 1; after mixing the product d4, isoquinoline, triethylamine, and DMSO, add mixture 1 in an ice-water bath. After adding, stir and react at 40°C for 8 h to obtain the product d5; add the product d5 into mixed solvent 1, add sodium dithionite under stirring at 55°C, and stir and react for 2 h to obtain the product d6; in a nitrogen atmosphere, mix the product d6, tetrahydrofuran, and toluene, add triphosgene at 65°C, stir and react for 1 h, then raise the temperature to 115°C, and stir and react for 2 h to obtain the modified glass fiber; the dosage ratio of p-nitrobenzoyl chloride and DMSO in mixture 1 is 19 g: 40 mL; the dosage ratio of the product d4, isoquinoline, triethylamine, DMSO, and mixture 1 is 15 g: 1.5 g: 13 g: 125 mL: 65 mL; the dosage ratio of the product d5, mixed solvent 1, and sodium dithionite is 18 g: 190 mL: 22 g, and the mixed solvent 1 is obtained by mixing methanol and tetrahydrofuran in a volume ratio of 3:2; the dosage ratio of the product d6, tetrahydrofuran, toluene, and triphosgene is 16 g: 60 mL: 110 mL: 12 g.

[0015] Example 5 A modified glass fiber, the preparation of which comprises the following steps: Step B1: Add glass fiber (supplier: Tai'an Haosong Fiber Co., Ltd., model: bb-7) into acetone, ultrasonically disperse for 30 min, take it out and wash it with deionized water until neutral, then vacuum dry at 75 °C for 6.5 h to obtain pretreated glass fiber; in a nitrogen atmosphere, mix the pretreated glass fiber, 2-fluoro-5-isocyanonitrobenzene, xylene, and stannous octoate, stir and react at 65 °C for 3.5 h, add phosphoric acid and continue to stir for 8 min, filter, wash three times with ethanol and acetone successively, and dry at 55 °C for 7.5 h to obtain product d1; the dosage ratio of glass fiber to acetone is 5.5 g: 95 mL; the dosage ratio of pretreated glass fiber, 2-fluoro-5-isocyanonitrobenzene, xylene, stannous octoate, and phosphoric acid is 8 g: 13 g: 115 mL: 0.030 g: 0.20 g, and the volume fraction of ethanol is 95%; Step B2: Mix product d1 and toluene, add sodium dithionite under stirring at 45 °C, stir and react for 2.3 h to obtain product d2; mix polyoxyethylene cetyl (5) ether, toluene, and alkali solution 1 and stir for 9 min, add epichlorohydrin, and stir and react at room temperature for 5.3 h to obtain product d3; mix product d2, product d3, and DMSO, and stir and react at 55 °C for 24.5 h to obtain product d4; the dosage ratio of product d1, toluene, and sodium dithionite is 9 g: 155 mL: 4.5 g; the dosage ratio of polyoxyethylene cetyl (5) ether, toluene, alkali solution 1, and epichlorohydrin is 49 g: 135 mL: 4 mL: 11 g, and alkali solution 1 is a potassium hydroxide solution with a mass fraction of 13%; the dosage ratio of product d2, product d3, and DMSO is 8 g: 61 g: 145 mL; Step B3: Mix p-nitrobenzoyl chloride and DMSO to obtain mixture 1; after mixing product d4, isoquinoline, triethylamine, and DMSO, add mixture 1 in an ice-water bath, and after adding, stir and react at 45 °C for 8.3 h to obtain product d5; add product d5 into mixed solvent 1, add sodium dithionite under stirring at 60 °C, stir and react for 2.3 h to obtain product d6; in a nitrogen atmosphere, mix product d6, tetrahydrofuran, and toluene, add triphosgene at 70 °C, stir and react for 1.3 h, then raise the temperature to 120 °C and stir and react for 2.3 h to obtain modified glass fiber; the dosage ratio of p-nitrobenzoyl chloride to DMSO in mixture 1 is 20 g: 45 mL; the dosage ratio of product d4, isoquinoline, triethylamine, DMSO, and mixture 1 is 18 g: 1.8 g: 14 g: 130 mL: 68 mL; the dosage ratio of product d5, mixed solvent 1, and sodium dithionite is 20 g: 195 mL: 24 g, and mixed solvent 1 is a mixture of methanol and tetrahydrofuran in a volume ratio of 3:2; the dosage ratio of product d6, tetrahydrofuran, toluene, and triphosgene is 17 g: 65 mL: 115 mL: 14 g.

[0016] Example 6 A modified glass fiber, the preparation of which comprises the following steps: Step B1: Add glass fiber (supplier: Tai'an Haosong Fiber Co., Ltd., model: bb-7) into acetone, ultrasonically disperse for 35 min, take it out, wash it with deionized water until neutral, and vacuum dry at 80 °C for 7 h to obtain pretreated glass fiber; in a nitrogen atmosphere, mix the pretreated glass fiber, 2-fluoro-5-isocyanatonitrobenzene, xylene, and stannous octoate, stir and react at 70 °C for 4 h, add phosphoric acid and continue to stir for 10 min, filter by suction, wash it three times with ethanol and acetone successively, and dry at 60 °C for 8 h to obtain product d1; the dosage ratio of glass fiber to acetone is 6 g: 100 mL; the dosage ratio of pretreated glass fiber, 2-fluoro-5-isocyanatonitrobenzene, xylene, stannous octoate, and phosphoric acid is 10 g: 15 g: 120 mL: 0.035 g: 0.25 g, and the volume fraction of ethanol is 95%; Step B2: Mix product d1 and toluene, add sodium dithionite under stirring at 50 °C, and stir and react for 2.5 h to obtain product d2; mix polyoxyethylene cetyl (5) ether, toluene, and alkali solution 1 and stir for 10 min, add epichlorohydrin, and stir and react at room temperature for 5.5 h to obtain product d3; mix product d2, product d3, and DMSO, and stir and react at 60 °C for 25 h to obtain product d4; the dosage ratio of product d1, toluene, and sodium dithionite is 10 g: 160 mL: 5 g; the dosage ratio of polyoxyethylene cetyl (5) ether, toluene, alkali solution 1, and epichlorohydrin is 50 g: 140 mL: 5 mL: 12 g, and alkali solution 1 is a potassium hydroxide solution with a mass fraction of 15%; the dosage ratio of product d2, product d3, and DMSO is 9 g: 62 g: 150 mL; Step B3: Mix p-nitrobenzoyl chloride and DMSO to obtain mixture 1; after mixing product d4, isoquinoline, triethylamine, and DMSO, add mixture 1 in an ice-water bath, and after adding, stir and react at 50 °C for 8.5 h to obtain product d5; add product d5 into mixed solvent 1, add sodium dithionite under stirring at 65 °C, and stir and react for 2.5 h to obtain product d6; in a nitrogen atmosphere, mix product d6, tetrahydrofuran, and toluene, add triphosgene at 75 °C, stir and react for 1.5 h, then raise the temperature to 125 °C, and stir and react for 2.5 h to obtain the modified glass fiber; the dosage ratio of p-nitrobenzoyl chloride to DMSO in mixture 1 is 21 g: 50 mL; the dosage ratio of product d4, isoquinoline, triethylamine, DMSO, and mixture 1 is 20 g: 2 g: 15 g: 135 mL: 70 mL; the dosage ratio of product d5, mixed solvent 1, and sodium dithionite is 22 g: 200 mL: 26 g, and mixed solvent 1 is obtained by mixing methanol and tetrahydrofuran according to a volume ratio of 3:2; the dosage ratio of product d6, tetrahydrofuran, toluene, and triphosgene is 18 g: 70 mL: 120 mL: 16 g.

[0017] Example 7 A heat-resistant high-elasticity polytetrafluoroethylene sealing ring, comprising the following raw materials in parts by weight: 65 parts of activated PTFE resin, 5 parts of polyimide (supplier: Shandong Qiansheng Chemical Co., Ltd., 1 kg), 1.5 parts of modified copper nanoparticles, 3 parts of modified glass fiber, 0.2 part of coupling agent, 0.5 part of dispersant; the coupling agent is KH550; the dispersant is polyvinylpyrrolidone; The preparation method of the activated PTFE resin is as follows: in a nitrogen atmosphere, soak the polytetrafluoroethylene resin (supplier: Dongguan Zhengtao Plastic Co., Ltd., model: XH0230KWA7SI) in a naphthalene sodium treatment solution (supplier: Wuhan Beileye Biomedical Technology Co., Ltd.) for 8 min, take it out and then soak it in acetone for 5 min, and then wash it with deionized water and dry it at 90 °C to obtain the activated PTFE resin; The preparation of the heat-resistant high-elasticity polytetrafluoroethylene sealing ring comprises the following steps: Stir the activated PTFE resin, polyimide, the modified copper nanoparticles obtained in Example 1, the modified glass fiber obtained in Example 4, the coupling agent, and the dispersant at a speed of 800 rpm for 10 min to obtain a mixture, press the mixture at 20 MPa for 40 min to form a green body, and let it stand in a drying oven at 30 °C for 24 h, then heat it up to 370 °C at a rate of 100 °C / h in a nitrogen atmosphere and keep it warm for 4 h, and then machine and grind it to make a sealing ring, and then anneal it at 120 °C for 1.5 h to obtain the heat-resistant high-elasticity polytetrafluoroethylene sealing ring.

[0018] Example 8 A heat-resistant high-elasticity polytetrafluoroethylene sealing ring, comprising the following raw materials in parts by weight: 70 parts of activated PTFE resin, 8 parts of polyimide (supplier: Shandong Qiansheng Chemical Co., Ltd., 1 kg), 1.8 parts of modified copper nanoparticles, 4 parts of modified glass fiber, 0.3 part of coupling agent, 0.6 part of dispersant; the coupling agent is KH550; the dispersant is polyvinylpyrrolidone; The preparation method of the activated PTFE resin is as follows: in a nitrogen atmosphere, soak the polytetrafluoroethylene resin (supplier: Dongguan Zhengtao Plastic Co., Ltd., model: XH0230KWA7SI) in a naphthalene sodium treatment solution (supplier: Wuhan Beileye Biomedical Technology Co., Ltd.) for 9 min, take it out and then soak it in acetone for 6 min, and then wash it with deionized water and dry it at 90 °C to obtain the activated PTFE resin; The preparation of the heat-resistant high-elasticity polytetrafluoroethylene sealing ring comprises the following steps: The activated PTFE resin, polyimide, modified copper nanoparticles obtained in Example 2, modified glass fibers obtained in Example 5, coupling agent, and dispersant were stirred at 900 rpm for 13 min to obtain a mixture. The mixture was pressed at 25 MPa for 45 min to form a green body, and then left standing in an oven at 30 °C for 24.5 h. Then, it was heated to 375 °C at a rate of 100 °C / h in a nitrogen atmosphere and held for 4.3 h. Subsequently, it was turned and ground to make a sealing ring, and then annealed at 125 °C for 1.8 h to obtain a heat-resistant and highly elastic polytetrafluoroethylene sealing ring.

[0019] Example 9 A heat-resistant and highly elastic polytetrafluoroethylene sealing ring, comprising the following raw materials in parts by weight: 75 parts of activated PTFE resin, 10 parts of polyimide (supplier: Shandong Qiansheng Chemical Co., Ltd., 1 kg), 2 parts of modified copper nanoparticles, 5 parts of modified glass fibers, 0.4 part of coupling agent, 0.7 part of dispersant; the coupling agent is KH550; the dispersant is polyvinylpyrrolidone; The preparation method of the activated PTFE resin is as follows: In a nitrogen atmosphere, polytetrafluoroethylene resin (supplier: Dongguan Zhengtao Plastic Co., Ltd., model: XH0230KWA7SI) was soaked in a naphthalene sodium treatment solution (supplier: Wuhan Beileye Biomedical Technology Co., Ltd.) for 10 min, taken out and then soaked in acetone for 7 min, and then washed with deionized water and dried at 90 °C to obtain the activated PTFE resin; The preparation of the heat-resistant and highly elastic polytetrafluoroethylene sealing ring comprises the following steps: The activated PTFE resin, polyimide, modified copper nanoparticles obtained in Example 3, modified glass fibers obtained in Example 6, coupling agent, and dispersant were stirred at 1000 rpm for 15 min to obtain a mixture. The mixture was pressed at 30 MPa for 50 min to form a green body, and then left standing in an oven at 30 °C for 25 h. Then, it was heated to 380 °C at a rate of 100 °C / h in a nitrogen atmosphere and held for 4.5 h. Subsequently, it was turned and ground to make a sealing ring, and then annealed at 130 °C for 2 h to obtain a heat-resistant and highly elastic polytetrafluoroethylene sealing ring.

[0020] Comparative Example 1 Compared with Example 9, o-carborane acetic acid in the preparation process of the modified copper nanoparticles was replaced with 1,3-bis(3-carboxypropyl)tetramethyldisiloxane, and the rest was exactly the same as in Example 9 to prepare a polytetrafluoroethylene sealing ring.

[0021] Comparative Example 2 Compared with Example 9, 7-amino-1,3,5-triazatricyclo[3.3.1.13,7]decane in the preparation process of the modified copper nanoparticles was replaced with 2-azatricyclo[3.3.1.13,7]decane, and the rest was exactly the same as in Example 9 to prepare a polytetrafluoroethylene sealing ring.

[0022] Comparative Example 3 Compared with Example 9, 4-nitro-1H-1,2,3-benzotriazole in the preparation process of the modified copper nanoparticles was replaced with N-methyl-p-nitroaniline, and the rest was exactly the same as Example 9 to prepare a polytetrafluoroethylene sealing ring.

[0023] Comparative Example 4 Compared with Example 9, the product c2 in the preparation process of the modified copper nanoparticles was replaced with the product c2-1 obtained by reacting 1-hydroxy-6-nitrobenzotriazole with the product c1, and the rest was exactly the same as Example 9 to prepare a polytetrafluoroethylene sealing ring. Preparation of the product c2-1: The dispersion obtained by mixing the product c1 prepared by the same preparation method as the product c1 used in the modified copper nanoparticles in Example 9 with DMSO was added dropwise to a mixed system of 1-hydroxy-6-nitrobenzotriazole (CAS No.: 26185-63-7), pyridine, triethylamine and DMSO in an ice-water bath, and stirred and reacted for 8 h to obtain the product c2-1; the dosage ratio of the product c1 to DMSO in the dispersion was 23 g:50 mL; the dosage ratio of the dispersion, 1-hydroxy-6-nitrobenzotriazole, pyridine, triethylamine and DMSO was 78 mL:22.5 g:1.1 g:13.4 g:85 mL.

[0024] Comparative Example 5 Compared with Example 9, polyoxyethylene cetyl (5) ether in the preparation process of the modified glass fiber was replaced with dodecaglycol monomethyl ether, and the rest was exactly the same as Example 9 to prepare a polytetrafluoroethylene sealing ring.

[0025] Comparative Example 6 Compared with Example 9, polyoxyethylene cetyl (5) ether in the preparation process of the modified glass fiber was replaced with hexacosanol, and the rest was exactly the same as Example 9 to prepare a polytetrafluoroethylene sealing ring.

[0026] Comparative Example 7 Compared with Example 9, the modified glass fiber was replaced with the modified glass fiber 1 obtained by reacting the product d6 with epichlorohydrin, and the rest was exactly the same as Example 9 to prepare a polytetrafluoroethylene sealing ring.

[0027] Preparation process of the modified glass fiber 1: The product d6, epichlorohydrin, tetrabutylammonium bromide and toluene prepared by the same preparation method as the product d6 used in the modified glass fiber in Example 9 were mixed and stirred and reacted at 100 °C for 5.5 h. After cooling, a sodium hydroxide solution with a mass fraction of 35% was added, and stirring was continued for 4.5 h to obtain the modified glass fiber 1; the dosage ratio of the product d6, epichlorohydrin, tetrabutylammonium chloride, toluene and the sodium hydroxide solution with a mass fraction of 35% was 21 g:48 g:4.5 g:240 mL:23 mL.

[0028] The following is a further effect test on the polytetrafluoroethylene sealing ring prepared by the present invention, and the test results are as follows.

[0029] Tensile strength: The tensile strength of the polytetrafluoroethylene sealing ring was determined with reference to GB / T1040.3-2006. The obtained polytetrafluoroethylene sealing ring was placed in an air oven at 280 °C for 7 days, and then the tensile strength retention rate after high-temperature oxidation was determined with reference to GB / T1040.3-2006 to evaluate the effect of the high-temperature oxidation resistance of the modified copper nanoparticles on the tensile strength of the polytetrafluoroethylene sealing ring, and further evaluate the heat resistance of the polytetrafluoroethylene sealing ring; the obtained polytetrafluoroethylene sealing ring was placed in an air environment at room temperature and 70% humidity for 30 days, and the tensile strength retention rate after high-humidity oxidation was determined with reference to GB / T1040.3-2006 to evaluate the effect of the water oxidation resistance of the modified copper nanoparticles on the tensile strength of the polytetrafluoroethylene sealing ring. Elastic modulus: The elastic modulus of the polytetrafluoroethylene sealing ring was tested using a WDW-1E microcomputer-controlled electronic universal testing machine with reference to GB / T5720-2008 "Test Methods for O-Ring Rubber Seals". The results are recorded in Table 1. Table 1: Test Results

[0030] According to the data in Table 1, the polytetrafluoroethylene sealing ring of the present invention has strong tensile strength, heat resistance and elasticity. Comparing Example 9 with Comparative Example 1, it can be seen that replacing o-carborane acetic acid in the preparation process of the modified copper nanoparticles with 1,3-bis(3-carboxypropyl)tetramethyldisiloxane and synergistically enhancing the modified copper nanoparticles with adamantane results in a decrease in high-temperature oxidation resistance, and the ability to avoid the exacerbation of the oxidation of the modified copper nanoparticles caused by water also decreases. Comparing Example 9 with Comparative Example 2, it can be seen that replacing 7-amino-1,3,5-triazabicyclo[3.3.1]nonane in the preparation process of the modified copper nanoparticles with 2-azabicyclo[3.3.1]nonane, the rigidity of 2-azabicyclo[3.3.1]nonane decreases due to weakened symmetry, and the synergistic enhancement of the high-temperature oxidation resistance of the modified copper nanoparticles with carborane decreases. Comparing Example 9 with Comparative Example 3, it can be seen that replacing 4-nitro-1H-1,2,3-benzotriazole in the preparation process of the modified copper nanoparticles with N-methyl-p-nitroaniline results in a decrease in the ability to form an adsorption film on the surface of the nano-copper powder synergistically with adamantane, and both the high-temperature oxidation resistance and the water oxidation resistance decrease. Comparing Example 9 with Comparative Example 4, it can be seen that replacing product c2 in the preparation process of the modified copper nanoparticles with the ester group formed by the reaction of 1-hydroxy-6-nitrobenzotriazole and product c1 weakens the compatibility between the modified copper nanoparticles and polyimide, resulting in a decrease in tensile strength, high-temperature oxidation resistance and water oxidation resistance. Comparing Example 9 with Comparative Example 5, it can be seen that replacing polyoxyethylene cetyl(5) ether in the preparation process of the modified glass fiber with 2-(2-methoxyethoxy)ethanol decreases the ability to compensate for the deficiency that the sealing ring is prone to brittle cracking under dynamic compression-rebound conditions during the process of the modified glass fiber improving the creep resistance and elasticity of the sealing ring, which is not conducive to the improvement of elasticity. Comparing Example 9 with Comparative Example 6, it can be seen that replacing polyoxyethylene cetyl(5) ether in the preparation process of the modified glass fiber with hexacosanol decreases the ability to compensate for the deficiency that the sealing ring is prone to brittle cracking under dynamic compression-rebound conditions during the process of the modified glass fiber improving the creep resistance and elasticity of the sealing ring, which is not conducive to the improvement of elasticity. Comparing Example 9 with Comparative Example 7, it can be seen that replacing the modified glass fiber with the modified glass fiber 1 obtained by the reaction of product d6 and epichlorohydrin results in a decrease in the interfacial bonding force between the modified glass fiber 1 and the activated polytetrafluoroethylene resin, resulting in a relatively large decrease in elasticity.

[0031] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the specific embodiments described or use similar methods to replace them. As long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they should all fall within the protection scope of the present invention.

Claims

1. A heat-resistant high-elasticity polytetrafluoroethylene sealing ring, characterized in that: It includes the following raw materials in parts by weight: 65-75 parts of activated PTFE resin, 5-10 parts of polyimide, 1.5-2 parts of modified copper nanoparticles, 3-5 parts of modified glass fiber, 0.2-0.4 parts of coupling agent, and 0.5-0.7 parts of dispersant; The preparation of the modified copper nanoparticles includes the following steps: Step A1: Mix carbon borane carboxylic acid with thionyl chloride to obtain product c1; drop the dispersion liquid b containing product c1 into the dispersion liquid a containing nitrobenzotriazole, and stir and react to obtain product c2; Step A2: Reduce product c2 with a reducing agent to obtain product c3; react 7-amino-1,3,5-triazaadamantane with epichlorohydrin under the action of a catalyst, cool and add an alkaline solution, and react to obtain product c4; mix and stir product c3, product c4, and DMAC to obtain product c5; Step A3: Hydrolyze silane in a mixed solvent to obtain a hydrolysis solution; treat nano copper powder with an acid solution to obtain pretreated copper powder; Mix and react the pretreated copper powder, the hydrolysis solution, and xylene to obtain product c6; Step A4: Mix and stir product c5, tetrahydrofuran, ethanol, potassium carbonate, and product c6, and then add triethylamine and react to obtain modified copper nanoparticles.

2. A heat-resistant high-elastic polytetrafluoroethylene sealing ring according to claim 1, characterized in that: In step A1, the carbon borane carboxylic acid is o-carborane acetic acid, and the nitrobenzotriazole is 4-nitro-1H-1,2,3-benzotriazole.

3. A heat-resistant and highly elastic polytetrafluoroethylene sealing ring according to claim 1, characterized in that: In step A2, the 7-amino-1,3,5-triazaadamantane is 7-amino-1,3,5-triazaadamantane; in step A3, the silane is bromobutyltrimethoxysilane.

4. A heat-resistant high-elasticity polytetrafluoroethylene sealing ring according to claim 1, characterized in that: The preparation of the modified glass fiber includes the following steps: Step B1: Add glass fiber to acetone for pretreatment to obtain pretreated glass fiber; in an inert gas atmosphere, mix and react the pretreated glass fiber, isocyanate, xylene, and stannous octoate, then add phosphoric acid and stir and post-treat to obtain product d1; Step B2: Reduce product d1 with sodium dithionite to obtain product d2; react a terminal hydroxyl ether with epichlorohydrin under alkaline conditions to obtain product d3; mix and react product d2, product d3, and DMSO to obtain product d4; Step B3: Mix p-nitrobenzoyl chloride and DMSO to obtain mixture 1; react product d4 with p-nitrobenzoyl chloride in mixture 1 to obtain product d5; mix product d5 and mixed solvent 1, and obtain product d6 under the action of sodium dithionite; in an inert gas atmosphere, mix and react product d6 with triphosgene to obtain modified glass fiber.

5. A heat-resistant high-elastic polytetrafluoroethylene sealing ring according to claim 4, characterized in that: In step B1, the isocyanate is 2-fluoro-5-isocyanatonitrobenzene.

6. A heat-resistant high-elasticity polytetrafluoroethylene sealing ring according to claim 4, characterized in that: In step B2, the terminal hydroxyl ether is polyoxyethylene cetyl(5) ether; in step B3, the p-nitrobenzoyl chloride is p-nitrobenzoyl chloride.

7. A heat-resistant high-elasticity polytetrafluoroethylene sealing ring according to claim 1, characterized in that: The preparation method of the activated PTFE resin is: in an inert gas atmosphere, soak the polytetrafluoroethylene resin in a naphthalene sodium treatment solution for 8-10 min, take it out and then soak it in acetone for 5-7 min, and then wash it with deionized water and dry it to obtain the activated PTFE resin.

8. A method for preparing a heat-resistant highly elastic polytetrafluoroethylene sealing ring according to any one of claims 1-7, characterized in that: It includes the following steps: Stir the activated PTFE resin, polyimide, modified copper nanoparticles, modified glass fiber, coupling agent, and dispersant at a high speed to obtain a mixture, press the mixture into a green body, let it stand in a drying oven, then heat up and keep warm in an atmosphere of protective gas, then machine and grind to make a sealing ring, and then perform annealing treatment to obtain a heat-resistant and highly elastic polytetrafluoroethylene sealing ring.

9. The preparation method of a heat-resistant and highly elastic polytetrafluoroethylene sealing ring according to claim 8, characterized in that: The high speed used is 800 - 1000 rpm; the pressure used for pressing the mixture into a green body is 20 - 30 MPa.

10. The preparation method of a heat-resistant high-elastic polytetrafluoroethylene sealing ring according to claim 8, characterized in that: The heat preservation temperature is 370 - 380 °C; the annealing treatment temperature is 120 - 130 °C.

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