A fluororubber material for sealing rings and its preparation method

Abstract

This invention discloses a fluororubber material for sealing rings, comprising, by weight: 100 parts fluororubber, 50-60 parts composite filler, and 1-2 parts crosslinking agent; wherein the composite filler is composed of carbon black, cysteine-modified molybdenum disulfide nanosheets, and modified graphene. This invention also discloses a method for preparing the fluororubber material for sealing rings, comprising the following steps: mixing fluororubber and composite filler, adding a crosslinking agent and mixing thoroughly, and then performing segmented vulcanization to obtain the fluororubber material for sealing rings. This invention thus achieves a synergistic effect in terms of self-lubrication, thermal conductivity, crosslinking density, and interfacial compatibility, resulting in fluororubber exhibiting excellent wear resistance and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of rubber technology, and in particular to a fluororubber material for sealing rings and its preparation method. Background Technology

[0002] Although small, rubber and plastic seals are essential components and accessories in major sectors of the national economy, such as defense, chemical, petroleum, coal, transportation, and machinery manufacturing, and play a vital role in national economic development.

[0003] Fluororubber is a synthetic polymer elastomer containing fluorine atoms on the carbon atoms of its main chain or side chains. The introduction of fluorine atoms endows the rubber with excellent heat resistance, oxidation resistance, oil resistance, corrosion resistance, and atmospheric aging resistance, making it a commonly used material for rubber and plastic seals. However, fluororubber has relatively low wear resistance, necessitating improvements to its wear resistance properties. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a fluororubber material for sealing rings and its preparation method. The present invention achieves a combination of multiple aspects such as self-lubrication, thermal conductivity, crosslinking density, and interfacial compatibility, so that fluororubber has good wear resistance and mechanical properties.

[0005] This invention proposes a fluororubber material for sealing rings, the raw materials of which include, by weight: 100 parts of fluororubber, 50-60 parts of composite filler, and 1-2 parts of crosslinking agent; wherein, the composite filler is composed of carbon black, cysteine-modified molybdenum disulfide nanosheets, and modified graphene.

[0006] Preferably, in the preparation process of modified graphene, graphene oxide coated with a polydopamine layer is mixed with an aqueous solution of amino-grafted modified boron nitride nanosheets and electrostatically assembled to obtain modified molybdenum disulfide nanosheets.

[0007] This invention utilizes polydopamine-coated graphene oxide with negative charges and amino-grafted boron nitride nanosheets, which can electrostatically self-assemble in an acidic environment. The polydopamine coating improves the insulation of graphene while maintaining good thermal conductivity, and works in conjunction with the boron nitride nanosheets to further enhance both insulation and thermal conductivity. This allows for timely heat dissipation from wear, preventing internal temperature rise and chain pyrolysis under thermal oxidation, thus improving rubber wear resistance. Furthermore, graphene's self-lubricating properties further enhance wear resistance. Additionally, the polydopamine layer and amino grafting modification improve the compatibility of graphene, boron nitride nanosheets, and fluororubber, thereby improving the mechanical properties of fluororubber. Moreover, the o-phenolic hydroxyl groups in the polydopamine layer can participate in the crosslinking of fluororubber, working in conjunction with crosslinking agents to improve interfacial compatibility and crosslinking density, inhibiting crack formation and further enhancing wear resistance and mechanical properties.

[0008] Preferably, the weight ratio of graphene oxide coated with a polydopamine layer to amino-grafted boron nitride nanosheets is 8-9:1-2.

[0009] Preferably, electrostatic assembly is performed after allowing the sample to stand for 10-12 hours.

[0010] Preferably, the aqueous solution of amino-grafted modified boron nitride nanosheets has a pH of 3.5-4.5.

[0011] Preferably, the amino-grafted modified boron nitride nanosheets are boron nitride nanosheets modified with silane coupling agents containing amino groups.

[0012] The aforementioned amino-containing silane coupling agents can be 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, etc.

[0013] The graphene oxide coated with the polydopamine layer can be prepared by the following method, specifically including the following steps: adding dopamine hydrochloride to the graphene oxide dispersion and mixing, then adding Tris-HCl buffer solution with pH=8.5 and mixing, stirring at room temperature for 8-10 hours, separating the solid and liquid, washing, and drying to obtain graphene oxide coated with the polydopamine layer; preferably, the weight ratio of graphene oxide to dopamine hydrochloride is 1:18-22.

[0014] Preferably, the weight ratio of carbon black, cysteine-modified molybdenum disulfide nanosheets, and modified graphene is 30-40:10-15:5-10.

[0015] Carbon black has good wear resistance, and molybdenum disulfide has good self-lubricating properties. This invention uses carbon black, cysteine-modified molybdenum disulfide nanosheets, and modified graphene in combination to further improve the wear resistance of rubber. Furthermore, the cysteine-modified molybdenum disulfide nanosheets contain active amino and carboxyl groups, which can covalently bond with the active groups in polydopamine in modified graphene, further improving interfacial compatibility, thereby enhancing the wear resistance and mechanical properties of rubber.

[0016] Preferably, the raw materials for the fluororubber material used in the sealing ring further include: vulcanization accelerator, plasticizer, and antioxidant.

[0017] The crosslinking agent mentioned above can be bisphenol AF, the vulcanization accelerator can be accelerator BTPPC, and the plasticizer can be tributyl acetylacetate, etc.

[0018] The present invention also proposes a method for preparing the above-mentioned fluororubber material for sealing rings, comprising the following steps: mixing fluororubber and composite filler, then adding a crosslinking agent and mixing evenly, and vulcanizing in stages to obtain the fluororubber material for sealing rings.

[0019] Preferably, the segmented vulcanization process is as follows: vulcanize at 150-160℃ for 10-15 minutes, and vulcanize at 210-220℃ for 18-20 hours.

[0020] Beneficial effects:

[0021] This invention utilizes polydopamine-coated graphene oxide nanosheets with negative charges and amino-grafted boron nitride nanosheets, which can electrostatically self-assemble in an acidic environment. The polydopamine coating can improve the insulation of graphene while maintaining good thermal conductivity, and it works in conjunction with boron nitride nanosheets to further enhance its insulation and thermal conductivity. Furthermore, it works in conjunction with carbon black and cysteine-modified molybdenum disulfide nanosheets, thereby achieving a synergistic effect in terms of self-lubrication, thermal conductivity, crosslinking density, and interfacial compatibility, resulting in fluororubber with excellent wear resistance and mechanical properties. Detailed Implementation

[0022] The technical solution of the present invention will be described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0023] Example 1

[0024] A fluororubber material for sealing rings comprises, by weight, 100 parts fluororubber, 50 parts composite filler, 1 part bisphenol AF, 1 part accelerator BTPPC, and 10 parts tributyl acetylacetate; wherein the composite filler is composed of carbon black N234, cysteine-modified molybdenum disulfide nanosheets, and modified graphene in a weight ratio of 30:15:5.

[0025] In the preparation of modified graphene, dopamine hydrochloride was added to the aqueous dispersion of graphene oxide and mixed well. Then, Tris-HCl buffer solution with pH=8.5 was added and mixed well. The mixture was stirred at room temperature for 10 h, centrifuged, the solid was washed, and dried under reduced pressure at 60 °C to obtain graphene oxide coated with polydopamine layer. The weight ratio of graphene oxide to dopamine hydrochloride was 1:18.

[0026] Graphene oxide coated with polydopamine was mixed with an aqueous solution of 3-aminopropyltriethoxysilane boron nitride nanosheets at pH 4.5, and electrostatically assembled after standing at room temperature for 12 h. The solid was then centrifuged, washed with water, and dried to obtain modified molybdenum disulfide nanosheets. The weight ratio of polydopamine-coated graphene oxide to 3-aminopropyltriethoxysilane-modified boron nitride nanosheets was 8:2.

[0027] The preparation method of the above-mentioned fluororubber material for sealing rings includes the following steps: mixing fluororubber, composite filler, and tributyl acetyl citrate, then adding bisphenol AF and accelerator BTPPC and mixing evenly, vulcanizing at 150-160℃ for 10 min, and vulcanizing at 210-220℃ for 18 h to obtain the fluororubber material for sealing rings.

[0028] Example 2

[0029] A fluororubber material for sealing rings comprises, by weight, 100 parts fluororubber, 60 parts composite filler, 2 parts bisphenol AF, 1 part accelerator BTPPC, and 10 parts tributyl acetylacetate; wherein the composite filler is composed of carbon black N234, cysteine-modified molybdenum disulfide nanosheets, and modified graphene in a weight ratio of 40:10:10.

[0030] In the preparation of modified graphene, dopamine hydrochloride was added to the aqueous dispersion of graphene oxide and mixed well. Then, Tris-HCl buffer solution with pH=8.5 was added and mixed well. The mixture was stirred at room temperature for 8 hours, centrifuged, the solid was washed, and dried under reduced pressure at 60℃ to obtain graphene oxide coated with polydopamine layer. The weight ratio of graphene oxide to dopamine hydrochloride was 1:22.

[0031] Graphene oxide coated with polydopamine was mixed with an aqueous solution of 3-aminopropyltriethoxysilane boron nitride nanosheets at pH 3.5, and electrostatically assembled after standing at room temperature for 10 h. The solid was then centrifuged, washed with water, and dried to obtain modified molybdenum disulfide nanosheets. The weight ratio of polydopamine-coated graphene oxide to 3-aminopropyltriethoxysilane-modified boron nitride nanosheets was 9:1.

[0032] The preparation method of the above-mentioned fluororubber material for sealing rings includes the following steps: fluororubber, composite filler, and tributyl acetyl citrate are mixed, then bisphenol AF and accelerator BTPPC are added and mixed evenly, vulcanized at 150-160℃ for 15 min, and vulcanized at 210-220℃ for 20 h to obtain the fluororubber material for sealing rings.

[0033] Example 3

[0034] A fluororubber material for sealing rings comprises, by weight, 100 parts fluororubber, 55 parts composite filler, 1.5 parts bisphenol AF, 1 part accelerator BTPPC, and 10 parts tributyl acetylacetate; wherein the composite filler is composed of carbon black N234, cysteine-modified molybdenum disulfide nanosheets, and modified graphene in a weight ratio of 35:12:8.

[0035] In the preparation of modified graphene, dopamine hydrochloride was added to the aqueous dispersion of graphene oxide and mixed well. Then, Tris-HCl buffer solution with pH=8.5 was added and mixed well. The mixture was stirred at room temperature for 9 hours, centrifuged, the solid was washed, and dried under reduced pressure at 60℃ to obtain graphene oxide coated with polydopamine layer. The weight ratio of graphene oxide to dopamine hydrochloride was 1:20.

[0036] Graphene oxide coated with polydopamine was mixed with an aqueous solution of 3-aminopropyltriethoxysilane boron nitride nanosheets at pH 4, and electrostatically assembled after standing at room temperature for 11 h. The solid was then centrifuged, washed with water, and dried to obtain modified molybdenum disulfide nanosheets. The weight ratio of polydopamine-coated graphene oxide to 3-aminopropyltriethoxysilane-modified boron nitride nanosheets was 8.5:1.5.

[0037] The preparation method of the above-mentioned fluororubber material for sealing rings includes the following steps: mixing fluororubber, composite filler, and tributyl acetyl citrate, then adding bisphenol AF and accelerator BTPPC and mixing evenly, vulcanizing at 150-160℃ for 12 min, and vulcanizing at 210-220℃ for 19 h to obtain the fluororubber material for sealing rings.

[0038] Comparative Example 1

[0039] Replace “modified graphene” with “graphite oxide coated with polydopamine layer”, otherwise the same as in Example 3.

[0040] Comparative Example 2

[0041] Replace “modified graphene” with “3-aminopropyltriethoxysilane boron nitride nanosheets”, otherwise the same as in Example 3.

[0042] Comparative Example 3

[0043] Replace “modified graphene” with “unmodified graphene oxide and unmodified boron nitride nanosheets in a weight ratio of 8.5:1.5”, and the rest is the same as in Example 3.

[0044] Comparative Example 4

[0045] Replace “cysteine-modified molybdenum disulfide nanosheets” with “unmodified molybdenum disulfide nanosheets”, otherwise the same as in Example 3.

[0046] The performance of the rubber samples prepared in Examples 1-3 and Comparative Examples 1-4 was tested, and the results are shown in Table 1.

[0047] Tensile strength was tested according to GB / T 528-2009, tear strength according to GB / T 529-2008, and abrasion was tested according to GB / T 9867-2008.

[0048] Table 1 Test Results

[0049]

[0050]

[0051] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A fluoroelastomer material for sealing rings, characterized by, Its raw materials include, by weight: 100 parts fluororubber, 50-60 parts composite filler, and 1-2 parts crosslinking agent; wherein, the composite filler is composed of carbon black, cysteine-modified molybdenum disulfide nanosheets, and modified graphene. The weight ratio of carbon black, cysteine-modified molybdenum disulfide nanosheets, and modified graphene is 30-40:10-15:5-10. In the preparation of modified graphene, graphene oxide coated with a polydopamine layer is mixed with an aqueous solution of amino-grafted modified boron nitride nanosheets and electrostatically assembled to obtain modified graphene.

2. The fluoroelastomer material for a seal ring according to claim 1, characterized by The weight ratio of graphene oxide coated with polydopamine layer to amino-grafted boron nitride nanosheets is 8-9:1-2.

3. The fluoroelastomer material for a seal ring according to claim 1, wherein Let it stand for 10-12 hours before electrostatic assembly.

4. The fluoroelastomer material for a seal ring according to claim 1, wherein The aqueous solution of amino-grafted modified boron nitride nanosheets has a pH of 3.5-4.

5.

5. The fluororubber material for the sealing ring according to claim 1, characterized in that, Amino-grafted modified boron nitride nanosheets are boron nitride nanosheets modified with amino-containing silane coupling agents.

6. The fluororubber material for the sealing ring according to claim 1, characterized in that, The raw materials for the fluororubber material used in the sealing ring also include: vulcanization accelerator, plasticizer, and antioxidant.

7. A method for preparing a fluororubber material for a sealing ring as described in any one of claims 1-6, characterized in that, The process includes the following steps: mixing fluororubber and composite fillers, adding a crosslinking agent and mixing thoroughly, and then vulcanizing in stages to obtain fluororubber material for sealing rings.

8. The method for preparing the fluororubber material for the sealing ring according to claim 7, characterized in that, The segmented vulcanization process is as follows: vulcanize at 150-160℃ for 10-15 minutes, and vulcanize at 210-220℃ for 18-20 hours.

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