Graphene modified rubber composite material and application thereof

Abstract

The invention relates to the technical field of rubber composite materials, in particular to a graphene modified rubber composite material and application thereof. According to the graphene modified rubber composite material and the preparation method thereof, sulfydryl-carboxyl dual-functionalized graphene is introduced synergistically, a double-effect reinforcing system of interface chemical bonding-space dispersion supporting is constructed, and the graphene modified rubber composite material is obtained. In the vulcanization process, thiolated graphene and a rubber molecular chain are subjected to a cross-linking reaction, and the interface interaction between graphene and a rubber matrix is remarkably enhanced. The agglomeration tendency of the functionalized graphene in the matrix is effectively inhibited, and the heat conduction efficiency, the mechanical strength and the low-fatigue temperature rise performance of the rubber composite material are synchronously improved. Meanwhile, the oxygen-containing functional group and the high specific surface area characteristic of the carboxylated graphene further promote the uniform dispersion of the functionalized graphene in the matrix. Through the synergistic effect of the two kinds of functionalized graphene, the comprehensive performance of the composite material is remarkably improved, so that the application of the composite material in tire preparation is expanded.

Description

Technical Field

[0001] The present application relates to the technical field of rubber composites, and more specifically, to a graphene-modified rubber composite material and applications thereof. Background Art

[0002] Carbon-based filler reinforced rubber composites, represented by carbon black, play an indispensable role in many industrial fields such as transportation, sealing protection, and shock absorption and damping due to their unique viscoelasticity, low elastic modulus, and reversible deformation. However, the high surface energy and large specific surface area of carbon-based fillers make them very easy to agglomerate in the rubber matrix. This agglomeration behavior will significantly deteriorate the dispersion effect of the filler in the rubber matrix, thereby weakening the interfacial interaction between the filler and the rubber matrix. The weakening of the interfacial interaction will trigger a series of chain reactions: on the one hand, the thermal conductivity of the composite material decreases, and the heat cannot be dissipated in time, resulting in an increase in the internal temperature of the material; on the other hand, the static and dynamic mechanical properties deteriorate, and the material is more likely to deform and damage when subjected to external forces. In addition, the increase in fatigue temperature rise will accelerate the aging process of the rubber material, causing it to fail prematurely, which not only increases the equipment maintenance cost, but also may bring serious safety hazards and cause huge economic losses. With the continuous advancement of science and technology and the accelerated advancement of industrialization, various industries have put forward more stringent requirements on the performance of rubber composite materials. Especially in the fields of high-end equipment manufacturing, new energy vehicles, etc., the requirements for mechanical properties, thermal conductivity and low fatigue temperature rise performance of materials have reached unprecedented heights. Therefore, the development of functional filler reinforced composite materials with excellent mechanical properties, high thermal conductivity and low fatigue temperature rise performance has become a key issue to be solved in the current rubber industry, which has important industrial application value and scientific research significance.

[0003] From the perspective of materials science, the performance of reinforced rubber composites essentially depends on the interfacial interaction between fillers and rubber matrix. This interaction is affected by a combination of factors, including the physical and chemical properties of the composite components (fillers and rubber), the type of interfacial interaction (such as van der Waals forces and hydrogen bonds, etc.), and the filler content. Among them, the key to filler-rubber interaction lies in the degree of compatibility between fillers and rubber. Taking graphite as an example, it has extremely strong polarity and is difficult to interact well with non-polar rubber, resulting in low interfacial bonding strength and the inability to fully exert the reinforcing effect of the filler. Therefore, changing the structure of the filler surface and enhancing the interfacial interaction between the filler and the matrix is an effective way to improve the thermal conductivity and mechanical properties of rubber composites.

[0004] At present, some studies have been dedicated to improving the properties of rubber composites through surface modification of fillers. For example, Chinese Patent Application (CN118027527A) discloses a technology that utilizes the vulcanization reaction between mercapto-functionalized graphene and rubber to generate monosulfide bonds, thereby enhancing the interfacial interaction between graphene and the rubber matrix, improving the mechanical and thermal conductivity properties of the rubber composite to a certain extent, and reducing the heat generation during compression fatigue. However, this technology has the following limitations in practical applications: on the one hand, the functionalized graphene prepared by this technology is only single-mercapto-functionalized graphene, which results in a minimum heat generation during compression fatigue of the rubber composite as high as 16.62 °C, leaving significant room for improvement in terms of low-fatigue temperature rise performance and making it difficult to meet the performance requirements of rubber composites; on the other hand, the modification method of mercapto-functionalized graphene in this technology is relatively cumbersome and is divided into two steps: first, the graphene slurry needs to be ball-milled for 15 - 120 min; then, the mercapto-containing silane coupling agent is added to the alcohol aqueous solution, hydrolyzed for a certain period of time, the pH value is adjusted, and then the ball-milled graphene slurry is added for heating reaction. After freeze-drying, the ball-milled-mercapto synergistically modified graphene oxide can be obtained. This complex preparation process not only increases the production cost but also limits its large-scale industrial application. Summary of the Invention

[0005] The technical problem to be solved by this application is to overcome the defects and deficiencies in the prior art that the types of surface functionalization modification of graphene are limited, resulting in poor low-fatigue temperature rise performance of rubber composites and the modification method of mercapto-functionalized graphene being relatively cumbersome, and to provide a graphene-modified rubber material.

[0006] Another object of the present invention is to provide the application of the above graphene-modified rubber material in the preparation of tires.

[0007] The above objects of the present invention are achieved by the following technical solutions:

[0008] The present invention protects a graphene-modified rubber composite, which is obtained by vulcanization crosslinking functionalized graphene and rubber in the presence of a vulcanizing agent.

[0009] The functionalized graphene includes mercapto-functionalized graphene and carboxyl-functionalized graphene.

[0010] In this application, by synergistically introducing mercapto-functionalized graphene and carboxyl-functionalized graphene, a dual-functional enhancement system of "enhanced interfacial strong bonding - spatially stable dispersion support" is constructed, significantly improving the comprehensive performance of rubber composites. Specifically: during the vulcanization process, the mercapto-functionalized graphene undergoes a cross-linking reaction with the rubber molecular chains, significantly enhancing the interfacial interaction between the graphene and the rubber matrix. This not only effectively inhibits the agglomeration tendency of the functionalized graphene in the matrix but also simultaneously improves the thermal conductivity efficiency, mechanical strength, and low fatigue temperature rise performance of the rubber composites. At the same time, the oxygen-containing functional groups and high specific surface area characteristics of the carboxyl-functionalized graphene further promote the uniform dispersion of the functionalized graphene in the matrix. The synergistic effect of these two functionalized graphenes significantly improves the comprehensive performance of the composite material, thus expanding the application of this composite material in the preparation of tires.

[0011] Furthermore, the preparation of the functionalized graphene includes the following steps: After subjecting the mixture of graphite and sulfur to dry ball milling treatment, it is purified to obtain the functionalized graphene.

[0012] In the present invention, the mixture of graphite and sulfur is subjected to dry ball milling treatment. Under the high-speed impact force of the grinding beads, while the graphite is exfoliated into graphene, the carbon-carbon bonds at the edges of the graphene are also broken, resulting in the generation of unstable carbon free radicals. Due to the presence of oxygen and water vapor in the ball milling environment, these carbon free radicals will combine with sulfur, oxygen, and water molecules to form carbon-sulfur-hydrogen bonds and carbon-oxygen-hydrogen bonds, thus forming mercapto-functionalized and carboxyl-functionalized graphene.

[0013] Furthermore, the functionalized graphene is edge-functionalized graphene.

[0014] Even further, the edge-functionalized graphene refers to a functionalized material obtained by chemically modifying the highly active unsaturated carbon atoms at the edges of the graphene sheets. These edge sites exhibit significant chemical reactivity due to the presence of unsaturated chemical bonds and become the main active sites for realizing the selective functionalization of graphene. After specific chemical modification treatment, these modified edge structures form edge-functionalized graphene materials with specific functions.

[0015] Even further, the graphite is one or more of flake graphite, expanded graphite, crystalline graphite, and graphite oxide.

[0016] Preferably, the mesh number of the graphite is 50 - 300 meshes.

[0017] Preferably, the sulfur is sulfur powder.

[0018] More preferably, the mesh number of the sulfur powder is 50 - 100 meshes.

[0019] Furthermore, the mass ratio of the graphite to the sulfur is 1:(0.01 - 2).

[0020] Further, the mass ratio of the graphite to the sulfur is 1:(0.05 - 1).

[0021] Preferably, the mass ratio of the graphite to the sulfur is 1:(0.08 - 0.5).

[0022] More preferably, the mass ratio of the graphite to the sulfur is 1:(0.1 - 0.3).

[0023] Preferably, the rotation speed of the dry ball milling is 100 - 500 rpm.

[0024] Preferably, the time of the dry ball milling is 0.5 - 48 h.

[0025] More preferably, the time of the dry ball milling is 12 - 24 h.

[0026] Further, the main purpose of the purification is to remove the excess sulfur.

[0027] Furthermore, as a preferred method, removing the excess sulfur means using carbon disulfide as a solvent and extracting the ball - milled mixture through a Soxhlet extractor to separate and purify the functionalized graphene.

[0028] Preferably, the temperature of the purification is 40 - 50 °C.

[0029] Preferably, the time of the purification is 6 - 24 h.

[0030] Further, the mass - to - volume ratio of the ball - milled mixture to the carbon disulfide is 1:(1 - 20) g / mL.

[0031] Furthermore, the mass ratio of the ball - milled mixture to the carbon disulfide is 1:(5 - 15) g / mL.

[0032] Further, the rubber includes one or more of natural rubber (NR), styrene - butadiene rubber (SBR), cis - 1,4 - polybutadiene rubber (BR), butyl rubber (IIR), chloroprene rubber (CR), nitrile - butadiene rubber (NBR), ethylene - propylene rubber (EPR).

[0033] Preferably, the form of the rubber is in blocks.

[0034] Preferably, the mass ratio of the rubber to the functionalized graphene is 1:(0.01 - 0.1).

[0035] Further, the vulcanizing agent includes one or more of sulfur, dimethyl phthalate, zinc oxide, and magnesium oxide. Through the vulcanization reaction, the above - mentioned vulcanizing agent can promote the formation of cross - linked structures between rubber molecular chains, thereby improving the physical and mechanical properties of the rubber.

[0036] Preferably, the mass ratio of the rubber to the vulcanizing agent is 1:(0.01-0.05).

[0037] Furthermore, the preparation of the graphene rubber composite material also includes adding an auxiliary agent.

[0038] Specifically, when an auxiliary agent is added, the method for preparing the graphene-modified rubber composite material comprises the following steps:

[0039] The functionalized graphene is mixed with rubber, a vulcanizing agent and an additive, and after kneading, vulcanization and cross-linking, a graphene-modified rubber composite material is obtained.

[0040] Furthermore, the auxiliary agent includes one or more of a lubricant, an antioxidant and a cross-linking accelerator.

[0041] Preferably, the lubricant includes one or more of stearic acid, microcrystalline wax, and a silane coupling agent.

[0042] Preferably, the mass ratio of the lubricant to the rubber is (0.001-0.1):1.

[0043] More preferably, the mass ratio of the lubricant to the rubber is (0.01-0.05):1.

[0044] Preferably, the antioxidant includes one or more of N-isopropyl-N'-phenyl-p-phenylenediamine, (1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (AW), 9,9-dimethylacridine (BLE), N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, tri-tert-butylphenol, 2,2'-methylenebis-(4-methyl-6-tert-butylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), 2-thiol methylbenzimidazole zinc salt (ZMMBI), N,N-di-n-butyldithiocarbamate nickel (NBC), 2-mercaptobenzimidazole (MB), and 2-mercaptobenzimidazole zinc salt (MBZ).

[0045] Preferably, the mass ratio of the antioxidant to the rubber is (0.01-0.05):1.

[0046] Preferably, the crosslinking accelerator includes one or more of N-cyclohexyl-2-benzothiazole sulfenamide (CZ), N-tert-butyl-2-benzothiazole sulfenamide (NS), N-(diethyleneglycol)-2-benzothiazole sulfenamide (NOBS), N-tert-butyl-2-benzothiazole sulfenamide (TBBS), tetrabenzylthiuram disulfide (TBZTD), tetramethylthiuram disulfide (TMTD), N,N'-dimethyl-N,N'-diphenylthiuram disulfide (DDTS), 2,2'-dithiobenzothiazole (DM), 4,4'-dithiomorpholine (DTDM), copper dimethyldithiocarbamate (DMTDC).

[0047] Preferably, the mass ratio of the crosslinking accelerator to the rubber is (0.01 - 0.05):1.

[0048] Furthermore, the temperature of the mixing is 50 - 60 °C.

[0049] Preferably, the mixing time is 5 - 10 min.

[0050] Furthermore, the temperature of the vulcanization crosslinking is 150 - 180 °C.

[0051] Preferably, the vulcanization crosslinking time is 8 - 15 min.

[0052] The present invention protects the application of the above graphene-modified rubber composite material in the preparation of tires.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] The present invention constructs a dual-effect enhancement system of "interface chemical bonding - spatial dispersion support" by synergistically introducing mercapto-carboxyl bifunctionalized graphene, and obtains a graphene-modified rubber composite material. During the vulcanization process, the mercapto-functionalized graphene undergoes a crosslinking reaction with the rubber molecular chains, significantly enhancing the interfacial interaction between the graphene and the rubber matrix. This not only effectively inhibits the agglomeration tendency of the functionalized graphene in the matrix, but also simultaneously improves the thermal conductivity efficiency, mechanical strength, and low fatigue temperature rise performance of the rubber composite material. At the same time, the oxygen-containing functional groups and high specific surface area characteristics of the carboxyl-functionalized graphene further promote the uniform dispersion of the functionalized graphene in the matrix. The synergistic effect of these two functionalized graphenes significantly improves the comprehensive performance of the composite material, thereby expanding the application of this composite material in the preparation of tires. Description of the Drawings

[0055] Figure 1X-ray photoelectron spectroscopy diagrams (a) of the rubber composites in Example 1 and Comparative Example 1, and (b)-(d) are C1s, O1s, and S2p spectra; among them, Graphite is the original graphite without ball milling, and SGnP is functionalized graphene.

[0056] Figure 2 SEM diagram of the rubber composite in Example 1.

[0057] Figure 3 SEM diagram of the rubber composite in Comparative Example 1.

[0058] Figure 4 SEM diagram of the rubber composite in Comparative Example 2. Detailed implementation manners

[0059] In order to make the purpose, technical solutions, and advantages of this application clearer, the following further details this application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0060] Scaly graphite (100 mesh) was purchased from Jiangsu Xianfeng Nano Materials Technology Co., Ltd.;

[0061] Sulfur powder (100 mesh) was purchased from Guangzhou Wenhan Scientific Instruments Co., Ltd.;

[0062] Natural rubber (standard rubber, block) was purchased from Shanghai Fuyou International Trade Co., Ltd.;

[0063] Antioxidants: N-isopropyl-N'-phenyl-p-phenylenediamine (4010NA) was purchased from Chengdu Huaxia Chemical Reagent Co., Ltd.; 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) was purchased from Shanghai Yantian Biotechnology Co., Ltd.;

[0064] Crosslinking accelerator: N-(diethyleneglycol)-2-benzothiazole sulfenamide (NOBS) was purchased from Guangzhou Kerong Biotechnology Co., Ltd.;

[0065] Trans-polyisoprene rubber powder (60 mesh) was purchased from Wuhan Lanabai Pharmaceutical and Chemical Co., Ltd.;

[0066] Figure 1 (a) represents Figure 1 Figure (a) in Figure 1 (b) represents Figure 1 Figure (b) in, and so on for other orders.

[0067] Example 1 Preparation of a graphene-modified rubber composite

[0068] S1. Mix 5 g of 100-mesh flake graphite with 1 g of 100-mesh sulfur powder, pour the mixture into a ball mill, stir for 1 min for pre-dispersion, and then ball mill at a speed of 300 rpm for 24 h to obtain a functionalized graphene mixture;

[0069] S2. Use carbon disulfide in a Soxhlet extractor to separate the elemental sulfur that has not reacted with graphene from the functionalized graphene mixture obtained in step S1 to obtain functionalized graphene including mercapto-functionalized graphene and carboxyl-functionalized graphene; the mass-volume ratio of the functionalized graphene mixture to carbon disulfide is 1:10 g / mL, the heating temperature of carbon disulfide is 46.3 °C, and the purification time is 12 h;

[0070] S3. Take 10 g of the functionalized graphene prepared according to the methods of steps S1 to S2, 100 g of natural rubber (standard rubber, block), 2 g of lubricant stearic acid, 1 g of antioxidant 4010NA, 1 g of antioxidant RD, 1 g of crosslinking accelerator NOBS, and 1.5 g of sulfur, and mix them on a two-roll rubber mixer at 55 °C for 10 min to obtain a mixed rubber;

[0071] S4. After preheating the vulcanizer at 150 °C for 0.5 h, put the mixed rubber obtained in step S3 into the vulcanizer for vulcanization crosslinking for 8 min to obtain a graphene-modified rubber composite.

[0072] Example 2 Preparation of a graphene-modified rubber composite

[0073] The difference from Example 1 is that in step S1, 1 g of sulfur powder is changed to 0.5 g of sulfur powder.

[0074] Other steps and conditions are the same as those in Example 1.

[0075] Example 3 Preparation of a graphene-modified rubber composite

[0076] The difference from Example 1 is that in step S3, 1.5 g of sulfur is changed to 1.8 g of sulfur.

[0077] Other steps and conditions are the same as those in Example 1.

[0078] Comparative Example 1 Preparation of a graphene-modified rubber composite

[0079] The difference from Example 1 is that in step S1, no sulfur powder is added; the product obtained in step S2 is carboxyl-functionalized graphene; the product obtained in step S4 is a carboxyl-functionalized graphene-modified rubber composite.

[0080] Other steps and conditions are the same as those in Example 1.

[0081] Comparative Example 2 Preparation of a graphene-modified rubber composite

[0082] The purpose of Comparative Example 2 is to provide a preparation method of the prior art, which improves the dispersion of graphene in the rubber composite, thereby enhancing its thermal conductivity and mechanical properties, so as to prepare a rubber composite with high thermal conductivity and high strength.

[0083] The difference from Example 1 is that in step S1, sulfur powder is replaced with trans-polyisoprene rubber powder and zinc oxide, and the specific operation is as follows:

[0084] S1. Mix 5 g of 100-mesh flake graphite with 10 g of 60-mesh trans-polyisoprene rubber powder, pour them into a ball mill, stir for 1 min for pre-dispersion, then ball mill at a speed of 300 rpm for 24 h, and then add 5 g of zinc oxide and ball mill at a speed of 300 rpm for 12 h to obtain carboxylated graphene;

[0085] S2. Take 10 g of carboxylated graphene prepared according to the method of step S1, 100 g of natural rubber (standard rubber, block), 2 g of lubricant stearic acid, 1 g of antioxidant 4010NA, 1 g of antioxidant RD, 1 g of accelerator NOBS, and 2 g of sulfur, and mix them on a two-roll rubber mill for 10 min to obtain a mixed rubber;

[0086] S3. After preheating the vulcanizer at 150 °C for 0.5 h, put the mixed rubber obtained in step S2 into the vulcanizer for vulcanization crosslinking for 8 min to obtain a carboxylated graphene-modified rubber composite.

[0087] Characterization of the rubber composite in Experimental Example 1

[0088] 1. X-ray photoelectron spectroscopy test

[0089] Use the X-ray photoelectron spectrometer Thermo Scientific K-Alpha of Thermo Fisher Scientific to test the chemical bonding of graphite in the rubber composites in Example 1 and Comparative Example 1. The results are as Figure 1 (a) shown. Two new peaks of S1s and S2p appear in the functionalized graphene, and peak fitting analysis is performed on them ( Figure 1 (b)–(d)). The characteristic peaks of C-S bond and O-C=O bond are found. This indicates that the carbon atoms in graphene form covalent bonds with the sulfur atoms in sulfur to generate mercapto (-SH), and at the same time form covalent bonds with the oxygen and hydrogen atoms in water molecules to generate carboxyl (-COOH). The above results successfully prove the formation of mercapto and carboxyl in the functionalized graphene, that is, the functionalized graphene obtained in Example 1 contains mercapto-graphene and carboxylated graphene.

[0090] 2. Scanning electron microscope (SEM) characterization

[0091] Take the rubber composites in Example 1 and Comparative Examples 1–2 for SEM characterization. The results are asFigures 2 to 4 As shown. The white dots in the figure represent the functionalized graphene in the rubber composite. The more uniform the distribution of the white dots, the better the dispersion of the functionalized graphene in the rubber composite. Conversely, it indicates that there is obvious agglomeration of the functionalized graphene in the rubber composite. From Figure 2 it can be seen that the functionalized graphene in Example 1 is uniformly dispersed in the rubber matrix and well infiltrated in the rubber matrix (see Figure 2 the annotation in Figure 3 ). It can be seen from Figure 3 that the carboxylated graphene in Comparative Example 1 is unevenly dispersed in the rubber matrix, showing obvious agglomeration phenomena (see Figure 4 the annotation in Figure 4 ).

[0092] Experimental Example 2 Performance Testing of Rubber Composites

[0093] 1. Experimental Method

[0094] (1) Thermal Conductivity: The thermal conductivity of the rubber composites in Examples 1-3 and Comparative Examples 1-3 was measured using the flat thermal conductivity meter TC3200 of Xi'an Xiaxi Electronic Technology Co., Ltd. The test specimens were rectangular with dimensions of 30 mm * 20 mm * 2 mm, and the test temperature was 25 °C.

[0095] (2) Tensile Strength: The tensile strength of the rubber composite samples in Examples 1-3 and Comparative Examples 1-3 was measured using the universal testing machine of Lishi (Shanghai) Scientific Instruments Co., Ltd. according to GB / T 528-2009. The shape of the test specimens was dumbbell-shaped with dimensions of 115 mm * 25 mm * 2 mm, the test speed was 500 mm / min, and the test temperature was 25 °C.

[0096] (3) Fatigue Temperature Rise: The fatigue temperature rise of the rubber composites in Examples 1-3 and Comparative Examples 1-3 was measured using the compression fatigue testing machine RH-3000N of CRRC Science & Technology Co., Ltd. according to GB / T1687-93. The test samples were cylindrical with a diameter of 17.8 mm and a height of 25 mm. The test temperature was 55 °C, the test frequency was 30 Hz, the prestress was 1 MPa, the stroke was 4.45 mm, and the test time was 25 min;

[0097] The above performance test results are shown in Table 1.

[0098] 2. Experimental Results

[0099] Table 1 Data Sheet of Performance Testing of Rubber Composites

[0100]

[0101]

[0102] As can be seen from Table 1, in the graphene-modified rubber composites of Examples 1 to 3, due to the uniform dispersion of functionalized graphene in the rubber matrix and good wetting with the rubber matrix, this structure is conducive to achieving efficient stress transfer between the rubber matrix and graphene, thereby significantly improving the thermal conductivity, tensile properties, and low fatigue temperature rise properties of the rubber composites. Specifically, the thermal conductivity is ≥1.5 W / (mK), the tensile strength is ≥20 MPa, and the fatigue temperature rise is ≤10 °C. In contrast, in Comparative Example 1, since no C-S bond was formed between the rubber and graphene, obvious agglomeration of graphene occurred, and the stress could not be evenly borne, resulting in a significant reduction in the tensile strength of the rubber composite and an increase in the fatigue temperature rise. In addition, the agglomeration of graphene also disrupted the heat conduction path of graphene in the rubber, reducing the thermal conductivity of the rubber composite. In Comparative Example 2, although graphene was relatively uniformly dispersed in the rubber powder, since no C-S bond was formed between the rubber and graphene, graphene agglomeration still occurred in some areas, resulting in a relatively high fatigue temperature rise of 18.5 ± 0.93 °C.

[0103] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A graphene-modified rubber composite material, characterized in that, vulcanizing and cross-linking the functionalized graphene and rubber in the presence of a vulcanizing agent to obtain a graphene-modified rubber composite material; The functionalized graphene includes thiol-functionalized graphene and carboxyl-functionalized graphene.

2. The graphene-modified rubber composite according to claim 1, wherein, The preparation of the functionalized graphene comprises the following steps: dry ball milling a mixture of graphite and sulfur, followed by purification to obtain the functionalized graphene.

3. The graphene-modified rubber composite material according to claim 1, wherein The vulcanizing agent includes one or more of sulfur, dimethyl phthalate, zinc oxide, and magnesium oxide.

4. The graphene-modified rubber composite according to claim 2, wherein, The mass ratio of the graphite to sulfur is 1:(0.01-2).

5. The graphene-modified rubber composite according to claim 1, wherein The rubber includes one or more of natural rubber, styrene-butadiene rubber, butadiene rubber, butyl rubber, chloroprene rubber, nitrile rubber, and ethylene-propylene rubber.

6. The graphene-modified rubber composite according to claim 1, wherein The preparation of the graphene-modified rubber composite material also includes adding an auxiliary agent.

7. The graphene-modified rubber composite according to claim 6, wherein The auxiliary agent includes one or more of a lubricant, an antioxidant, and a cross-linking accelerator.

8. The graphene-modified rubber composite according to claim 7, wherein The antioxidant includes one or more of N-isopropyl-N'-phenyl-p-phenylenediamine, (1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, 9,9-dimethylacridine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, tri-tert-butylphenol, 2,2'-methylenebis-(4-methyl-6-tert-butylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), 2-thiol methylbenzimidazole zinc salt, N,N-di-n-butyldithiocarbamate nickel, 2-mercaptobenzimidazole, and 2-mercaptobenzimidazole zinc salt.

9. The graphene-modified rubber composite according to claim 7, wherein The crosslinking accelerator includes one or more of N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, N-(diethylene oxide)-2-phenylpropionthiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, tetrabenzylthiuram disulfide, tetramethylthiuram disulfide, N,N'-dimethyl-N,N'diphenylthiuram disulfide, 2,2'-dibenzothiazole disulfide, 4,4'-dimorpholine disulfide, and copper dimethylaminodithiocarbamate.

10. Use of the graphene-modified rubber composite material according to any one of claims 1 to 9 in the preparation of tires.

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