CN117924701B - A superhard composite material containing diamond and graphene and preparation method - Google Patents

Abstract

The invention belongs to the technical field of organic-inorganic composite materials, and discloses a superhard composite material containing diamond and graphene and a preparation method thereof. The epoxy soluble polyimide contains rich epoxy groups, can perform epoxy ring-opening reaction with amino and carboxyl of modified graphene and amino of KH550 modified diamond in a high-temperature heat curing process, and has the advantages that chemical crosslinking is performed on the amino, carboxyl and amino of the modified graphene, and amino-carboxyl of the modified graphene are chemically crosslinked, so that the interface bonding strength between the diamond and the polyimide is enhanced, and the compatibility between the diamond and the graphene is improved; the diamond and the graphene are used as high-performance inorganic materials, have high hardness and mechanical strength, have good dispersibility in polyimide composite materials, and remarkably improve the tensile strength, bending modulus, impact strength and hardness of the composite materials.

Description

A superhard composite material containing diamond and graphene and preparation method

Technical Field

The invention belongs to the technical field of organic and inorganic composite materials, and specifically relates to a superhard composite material containing diamond and graphene and a preparation method thereof.

Background technique

Polyimide is a special engineering plastic with excellent comprehensive performance, high mechanical strength, good insulation performance, and strong high temperature resistance. It is widely used in separation membranes, high temperature structural adhesives, grinding wheels, fibers, etc. Combining polyimide with high-performance inorganic materials such as graphene, diamond, molybdenum disulfide, and carbon fiber can give full play to the advantages of organic and inorganic composite materials. Diamond is the hardest substance naturally existing in nature, with high wear resistance and high hardness. It can be combined with polyimide resin, epoxy resin, etc., and has broad application prospects in diamond grinding wheels, adhesives, etc. Graphene has strong mechanical strength, good high temperature resistance, and excellent electrochemical properties. It is considered to be a revolutionary nanomaterial in the future; however, whether it is diamond or graphene, the interface bonding performance with polymer materials such as polyimide is poor, and it is easy to agglomerate in the material matrix, which cannot effectively enhance the performance of polymer materials. Patent CN107129573B discloses that polydopamine and diamond nanoparticles are physically combined to form a composite, and the diamond nanoparticles are evenly dispersed in polyimide. The resulting diamond-reinforced polyimide nanocomposite material has excellent mechanical properties, high temperature resistance and wear resistance. Therefore, surface modification of diamond and graphene and combination with polyimide is an effective strategy to obtain organic-inorganic composite materials.

Summary of the invention

The technical problem to be solved is: preparing a superhard composite material containing diamond and graphene with high hardness, high strength and high wear resistance.

Technical solutions:

A superhard composite material containing diamond and graphene comprises 1-8 parts by weight of modified graphene, 15-35 parts by weight of KH550 modified diamond and 57-84 parts by weight of epoxy-soluble polyimide.

The preparation method of epoxy soluble polyimide is:

(1) Add N,N-dimethylformamide, 4,4'-biphenyl ether dianhydride and 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane in a ratio of 1 mol:(1.05-1.15) mol into a reaction container, introduce nitrogen gas to carry out an amidation reaction, then pour the solution into a mold, carry out a thermal imidization reaction, and cool to obtain a carboxyl-soluble polyimide.

(2) Add N,N-dimethylformamide and carboxyl-soluble polyimide to a reaction container, heat to 40-60°C and stir to dissolve, then add N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and glycidol, react for 6-24 hours, pour the solution into methanol to precipitate, filter, wash with water and ethanol in turn, and dry to obtain epoxy-soluble polyimide.

The preparation method of modified graphene is:

The graphene oxide is reacted with thionyl chloride to obtain chlorinated graphene; then the chlorinated graphene and tetrahydrofuran are added into a reaction container, and 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane and triethylamine are added, and the reaction is carried out at 15-30°C for 18-36h. After the reaction, the mixture is filtered, washed with ethanol, and dried to obtain modified graphene.

The amidation reaction in (1) is carried out at 25-30°C for 12-18h; the thermal imidization reaction is carried out at 140-160°C for 2-3h, 180-200°C for 3-5h, 240-260°C for 3-4h, and 270-280°C for 3-4h.

Among them, the ratio of carboxyl-soluble polyimide, N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and glycidol in (2) is 1g:(0.3-0.8)g:(0.05-0.15)g:(0.12-0.35)g.

Among them, in the preparation method of modified graphene, the ratio of chlorinated graphene, 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane and triethylamine is 1g:(5-20)g:(1.2-4.6)g.

Among them, the preparation method of 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane is: add N,N-dimethylformamide, 2-tert-butoxycarbonylamino-5-chlorobenzoic acid, hexafluorobisphenol A, and potassium carbonate into a reaction container, react at 80-110°C for 6-12 hours, add dichloromethane and water after cooling, extract and separate, dry and concentrate the organic layer, wash the product with methanol, then add it to dichloromethane, add trifluoroacetic acid, react at 20-30°C for 2-4 hours, concentrate to remove the solvent, wash with methanol, and recrystallize the product with dichloromethane to obtain 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane.

Wherein, the ratio of 2-tert-butoxycarbonylamino-5-chlorobenzoic acid, hexafluorobisphenol A and potassium carbonate is (2.2-2.4) mol:1 mol:(1.5-1.8) mol.

Among them, the preparation method of the superhard composite material containing diamond and graphene is as follows: N,N-dimethylformamide and 57-84 weight parts of epoxy-soluble polyimide are poured into a mold, stirred at 50-60°C for dissolution, and then 1-8 weight parts of modified graphene and 15-35 weight parts of KH550 modified diamond are added, ultrasonic dispersion is performed in an ultrasonic instrument, and then drying and heat curing are performed at 140-160°C to obtain a superhard composite material containing diamond and graphene.

Technical effect:

The present invention utilizes 2-tert-butoxycarbonylamino-5-chlorobenzoic acid and hexafluorobisphenol A to undergo etherification reaction and remove the Boc protecting group to obtain a novel fluorine- and carboxyl-containing diamine monomer 2,2'-bis(4-(4-amino-3-carboxylphenoxy)phenyl)hexafluoropropane, which is then polymerized with 4,4'-biphenyl ether dianhydride to obtain a carboxyl-containing soluble polyimide having good solubility in polar solvents such as N,N-dimethylformamide, and then undergoes an esterification reaction with glycidol to obtain an epoxy-soluble polyimide. Fluorine-containing groups are introduced into the polyimide molecular chain to improve its solubility in polar solvents such as N,N-dimethylformamide. This provides convenience for the subsequent reaction with modified graphene and modified diamond in the drying and heat curing process in N,N-dimethylformamide.

The present invention further utilizes an amino group of 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane to react with the acyl chloride group of acyl chloride graphene, thereby introducing functional amino groups, carboxyl groups and fluorine-containing groups on the surface of graphene to obtain modified graphene; finally, the graphene is blended and thermally cured with KH550 modified diamond and epoxy-soluble polyimide in N,N-dimethylformamide to obtain a superhard composite material; after being organically modified, the modified graphene and KH550 modified diamond have good interface compatibility with the epoxy-soluble polyimide. At the same time, epoxy-soluble polyimide contains abundant epoxy groups, which can undergo epoxy ring-opening reaction with the amino and carboxyl groups of modified graphene and the amino groups of KH550 modified diamond during the high-temperature process of thermal curing. The three are chemically cross-linked, and the interfacial bonding strength between diamond and graphene and polyimide is enhanced through chemical bonding, thereby improving the compatibility among the three. Diamond and graphene, as high-performance inorganic materials, have high hardness and mechanical strength in themselves, and have good dispersion in polyimide composites, which significantly improves the tensile strength, flexural strength, flexural modulus, impact strength and hardness of the composites.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a reaction route for preparing 2,2′-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane.

FIG2 is a reaction route for preparing epoxy-soluble polyimide.

Detailed ways

The diamond in the present invention has an average particle size of 8 μm and the graphene oxide has a thickness of 0.6 to 1.0 nm.

2-tert-Butyloxycarbonylamino-5-chlorobenzoic acid: CAS No. 253677-29-1.

Hexafluorobisphenol A: CAS No. 1478-61-1

4,4'-Biphenyl ether dianhydride: CAS No. 1823-59-2.

Glycidol: CAS No. 556-52-5.

Preparation of chlorinated graphene: 40 mL of thionyl chloride and 0.5 g of graphene oxide were added to a reaction container, and ultrasonic dispersion was performed in an ultrasonicator. The reaction was carried out at 75° C. for 24 h under a nitrogen atmosphere, and the chlorinated graphene was obtained by vacuum distillation and washing with dichloromethane.

Preparation of KH550 modified diamond: add 1g diamond and 110g/L sodium hydroxide solution to a reaction container, stir at 90℃ for 4h, take out the diamond, wash with water and dry, then add it to a toluene solution containing 20mg KH550, react at 90℃ for 4h, take out the diamond, wash with acetone and dry to obtain KH550 modified diamond.

Preparation of 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane: Add 100mL N,N-dimethylformamide, 44mmol 2-tert-butoxycarbonylamino-5-chlorobenzoic acid, 20mmol hexafluorobisphenol A, and 36mmol potassium carbonate to a reaction vessel, react at 110°C for 8h, add dichloromethane and water after cooling, extract and separate, dry and concentrate the organic layer, wash the product with methanol, then add it to 100mL dichloromethane, add 250mmol trifluoroacetic acid, react at 20°C for 3h, concentrate to remove the solvent, wash with methanol, and recrystallize the product with dichloromethane to obtain 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane. The structural formula is as follows:

Example 1

120 mL of N,N-dimethylformamide, 40 mmol of 4,4'-biphenyl ether dianhydride, and 42 mmol of 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane were added to a reaction container, nitrogen was introduced, and amidation reaction was carried out at 30°C for 12 hours. Then the solution was poured into a mold for thermal imidization reaction. The reaction was sequentially kept at 150°C for 3 hours, 180°C for 5 hours, 250°C for 4 hours, and 270°C for 4 hours, and then cooled to obtain a carboxyl-soluble polyimide.

Add 500 mL of N,N-dimethylformamide (DMF) and 3 g of carboxyl-soluble polyimide to a reaction container, heat to 40°C and stir to dissolve, then add 0.9 g of N,N-dicyclohexylcarbodiimide (DCC), 0.15 g of 4-dimethylaminopyridine (DMAP), and 0.36 g of propylene oxide, react for 6 hours, pour the solution into methanol to precipitate the precipitate, filter, wash with water and ethanol in turn, and dry to obtain epoxy-soluble polyimide.

Add 40 mL of tetrahydrofuran and 0.5 g of chlorinated graphene into a reaction container, perform ultrasonic dispersion in an ultrasonicator, add 2.5 g of 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane and 0.6 g of triethylamine, react at 30°C for 18 h, filter after the reaction, wash with ethanol, and dry to obtain modified graphene.

600 mL of N,N-dimethylformamide and 84 g of epoxy-soluble polyimide were poured into a mold and stirred at 60°C for dissolution. Then, 1 g of modified graphene and 15 g of KH550 modified diamond were added and ultrasonically dispersed in an ultrasonic instrument. The mixture was then dried and thermally cured at 140°C to obtain a superhard composite material containing diamond and graphene.

Example 2

150 mL of N,N-dimethylformamide, 40 mmol of 4,4'-biphenyl ether dianhydride, and 46 mmol of 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane were added to the reaction container, nitrogen was introduced, and amidation reaction was carried out at 25°C for 18 hours. Then the solution was poured into a mold for thermal imidization reaction. The reaction was sequentially kept at 160°C for 2 hours, 180°C for 5 hours, 240°C for 4 hours, and 280°C for 3 hours, and then cooled to obtain a carboxyl-soluble polyimide.

Add 600 mL of N,N-dimethylformamide and 3 g of carboxyl-soluble polyimide to a reaction container, heat to 60°C and stir to dissolve, then add 1.6 g of N,N-dicyclohexylcarbodiimide, 0.32 g of 4-dimethylaminopyridine, and 0.75 g of glycidol, react for 24 hours, pour the solution into methanol to precipitate the precipitate, filter, wash with water and ethanol in turn, and dry to obtain epoxy-soluble polyimide.

Add 50 mL of tetrahydrofuran and 0.5 g of chlorinated graphene into a reaction container, perform ultrasonic dispersion in an ultrasonicator, add 6.3 g of 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane and 1.4 g of triethylamine, react at 15°C for 36 h, filter after the reaction, wash with ethanol, and dry to obtain modified graphene.

800 mL of N,N-dimethylformamide and 70 g of epoxy-soluble polyimide were poured into a mold and stirred at 50°C for dissolution. Then, 5 g of modified graphene and 25 g of KH550 modified diamond were added and ultrasonically dispersed in an ultrasonic instrument. The mixture was then dried and thermally cured at 160°C to obtain a superhard composite material containing diamond and graphene.

Example 3

120 mL of N,N-dimethylformamide, 40 mmol of 4,4'-biphenyl ether dianhydride, and 42 mmol of 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane were added to a reaction container, nitrogen was introduced, and amidation reaction was carried out at 25°C for 18 hours. Then the solution was poured into a mold for thermal imidization reaction. The reaction was sequentially kept at 140°C for 3 hours, 200°C for 3 hours, 260°C for 3 hours, and 280°C for 3 hours, and then cooled to obtain a carboxyl-soluble polyimide.

Add 800 mL of N,N-dimethylformamide and 3 g of carboxyl-soluble polyimide to a reaction container, heat to 40°C and stir to dissolve, then add 2.4 g of N,N-dicyclohexylcarbodiimide, 0.45 g of 4-dimethylaminopyridine and 1.05 g of glycidol, react for 24 hours, pour the solution into methanol to precipitate the precipitate, filter, wash with water and ethanol in turn, and dry to obtain epoxy-soluble polyimide.

70 mL of tetrahydrofuran and 0.5 g of chlorinated graphene were added to a reaction container, and ultrasonic dispersion was performed in an ultrasonic instrument. 10 g of 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane and 2.3 g of triethylamine were added, and the mixture was reacted at 30°C for 24 h. After the reaction, the mixture was filtered, washed with ethanol, and dried to obtain modified graphene.

1000 mL of N,N-dimethylformamide and 57 g of epoxy-soluble polyimide were poured into a mold and stirred at 50°C for dissolution. Then, 8 g of modified graphene and 35 g of KH550 modified diamond were added and ultrasonically dispersed in an ultrasonic instrument. The mixture was then dried and thermally cured at 160°C to obtain a superhard composite material containing diamond and graphene.

Comparative Example 1

The difference between this comparative example and Example 1 is that no modified graphene and modified diamond are added to the epoxy-based soluble polyimide. Pure epoxy-based soluble polyimide is used as the superhard composite material.

Comparative Example 2

The difference between this comparative example and Example 1 is that carboxyl-soluble polyimide is used instead of epoxy-soluble polyimide.

600 mL of N,N-dimethylformamide and 84 g of carboxyl-soluble polyimide were poured into a mold and stirred at 60°C for dissolution. Then, 1 g of modified graphene and 15 g of KH550 modified diamond were added and ultrasonically dispersed in an ultrasonic instrument. The mixture was then dried and thermally cured at 140°C to obtain a superhard composite material.

Comparative Example 3

The difference between this comparative example and Example 1 is that diamond is used instead of KH550 modified diamond, and graphene oxide is used instead of modified graphene.

600 mL of N,N-dimethylformamide and 84 g of epoxy-soluble polyimide were poured into a mold and stirred at 60°C for dissolution. Then, 1 g of graphene oxide and 15 g of diamond were added and ultrasonically dispersed in an ultrasonic instrument. The mixture was then dried and thermally cured at 140°C to obtain a superhard composite material.

Comparative Example 4

The difference between this comparative example and Example 1 is that diamond is used instead of KH550 modified diamond.

600 mL of N,N-dimethylformamide and 84 g of epoxy-soluble polyimide were poured into a mold and stirred at 60°C for dissolution. Then, 1 g of modified graphene and 15 g of diamond were added and ultrasonically dispersed in an ultrasonic instrument. The mixture was then dried and thermally cured at 140°C to obtain a superhard composite material.

Comparative Example 5

The difference between this comparative example and Example 1 is that graphene oxide is used instead of modified graphene.

600 mL of N,N-dimethylformamide and 84 g of epoxy-soluble polyimide were poured into a mold and stirred at 60°C for dissolution. Then, 1 g of graphene oxide and 15 g of KH550 modified diamond were added and ultrasonically dispersed in an ultrasonic instrument. The mixture was then dried and thermally cured at 140°C to obtain a superhard composite material.

According to the method of GB/T2411-2008, the Shore hardness of superhard composite materials was tested using a Shore hardness tester.

According to GB/T 1040.1-2006 and GB/T 9341-2008 methods, the tensile strength and bending properties of superhard composite materials were tested using a universal material testing machine.

According to the method of GB/T1043.1-2008, the impact strength of superhard composite materials was tested using an impact testing machine.

Table 1 Performance test of superhard composite materials

The epoxy-soluble polyimide prepared by the embodiment of the present invention introduces a fluorine-containing group into the polyimide molecular chain, which can improve its solubility in polar solvents such as N,N-dimethylformamide. It is convenient to react with modified graphene and modified diamond in the subsequent drying and heat curing process in N,N-dimethylformamide. The epoxy-soluble polyimide contains abundant epoxy groups, which can react with the amino and carboxyl groups of modified graphene and the amino groups of KH550 modified diamond to form an epoxy ring-opening reaction. The three are chemically cross-linked, and the interfacial bonding strength between diamond and graphene and polyimide is enhanced through chemical bonding, and the compatibility between the three is improved. The dispersibility of diamond and graphene in the polyimide composite material is very good, which significantly improves the tensile strength, flexural strength, flexural modulus, impact strength and hardness of the composite material. The hardnesses are 167.2-193.0MPa, 219.2-240.7MPa, 10.72-11.83GPa, 68.4-91.3kJ/m ² and 82-89 Shore A respectively.

In the epoxy-soluble polyimide of Comparative Example 1, no modified graphene and modified diamond are added, and the tensile strength, bending performance, impact strength and hardness of the composite material are the lowest.

Comparative Example 2 uses carboxyl-soluble polyimide instead of epoxy-soluble polyimide, which does not contain epoxy groups and cannot undergo cross-linking reaction with the amino and carboxyl groups of modified graphene and KH550 modified diamond. The interfacial bonding strength between the three is low, but graphene and diamond have been organically modified, which can improve the compatibility with polyimide to a certain extent. The dispersion of the two in the polyimide composite material is good, and the tensile strength and other properties of the composite material are significantly improved, but the performance is lower than that of Example 1.

Comparative Example 3 uses diamond instead of KH550 modified diamond, and uses graphene oxide instead of modified graphene. Diamond and graphene oxide do not contain amino groups, and the carboxyl group activity on the surface of graphene oxide is low, and it is difficult to react with the epoxy group of epoxy-soluble polyimide, and it is difficult to form a chemical bond. The interface bonding strength between the two and polyimide is low, and the mechanical properties of the composite material are poor.

Comparative Example 4

The difference between this comparative example and Example 1 is that diamond is used instead of KH550 modified diamond, which does not contain amino groups; in Comparative Example 5, graphene oxide is used instead of modified graphene, which does not contain amino groups, and the carboxyl group activity on the surface of graphene oxide is low, making it difficult to form chemical bonds with the epoxy groups of epoxy-soluble polyimide, resulting in lower mechanical properties than Example 1.

Claims (7)

1. A superhard composite material containing diamond and graphene, characterized in that the superhard composite material containing diamond and graphene comprises 1-8 parts by weight of modified graphene, 15-35 parts by weight of KH550 modified diamond, and 57-84 parts by weight of epoxy-soluble polyimide; The preparation method of the epoxy-soluble polyimide is: (1) Adding N,N-dimethylformamide, 4,4'-biphenyl ether dianhydride, and 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane into a reaction container, introducing nitrogen gas to carry out an amidation reaction, then pouring the solution into a mold, carrying out a thermal imidization reaction, and cooling to obtain a carboxyl-soluble polyimide; (2) Add N,N-dimethylformamide and carboxyl-soluble polyimide to a reaction container, heat to 40-60°C and stir to dissolve, then add N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and glycidol, react for 6-24 hours, precipitate, filter, wash and dry to obtain epoxy-soluble polyimide; the ratio of carboxyl-soluble polyimide, N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and glycidol is 1g: (0.3-0.8)g: (0.05-0.15)g: (0.12-0.35)g; The preparation method of the modified graphene is: Graphene oxide is reacted with thionyl chloride to obtain chlorinated graphene; then chlorinated graphene and tetrahydrofuran are added into a reaction container, and 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane and triethylamine are added, and after the reaction, the mixture is filtered, washed and dried to obtain modified graphene; the ratio of chlorinated graphene, 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane and triethylamine is 1g:(5-20)g:(1.2-4.6)g. 2. The superhard composite material containing diamond and graphene according to claim 1, characterized in that the ratio of 4,4'-biphenyl ether dianhydride to 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane in (1) is 1 mol:(1.05-1.15) mol. 3. The superhard composite material containing diamond and graphene according to claim 1 is characterized in that the amidation reaction in (1) is carried out at 25-30°C for 12-18 hours; the thermal imidization reaction is carried out at 140-160°C for 2-3 hours, 180-200°C for 3-5 hours, 240-260°C for 3-4 hours, and 270-280°C for 3-4 hours. 4. The superhard composite material containing diamond and graphene according to claim 1, characterized in that in the preparation method of the modified graphene, the reaction is carried out at 15-30°C for 18-36 hours. 5. The superhard composite material containing diamond and graphene according to claim 1, characterized in that the preparation method of the 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane is: add N,N-dimethylformamide, 2-tert-butoxycarbonylamino-5-chlorobenzoic acid, hexafluorobisphenol A, and potassium carbonate into a reaction container, react at 80-110°C for 6-12 hours, extract and separate, wash the product, then add it to dichloromethane, add trifluoroacetic acid, react at 20-30°C for 2-4 hours, concentrate, wash, and recrystallize to obtain 2,2'-bis(4-(4-amino-3-carboxyphenoxy)phenyl)hexafluoropropane. 6. The superhard composite material containing diamond and graphene according to claim 5, characterized in that the ratio of 2-tert-butoxycarbonylamino-5-chlorobenzoic acid, hexafluorobisphenol A, and potassium carbonate is (2.2-2.4) mol:1 mol:(1.5-1.8) mol. 7. A method for preparing a superhard composite material containing diamond and graphene as described in any one of claims 1 to 6, characterized in that the preparation method is: pour N,N-dimethylformamide and 57-84 weight parts of epoxy-soluble polyimide into a mold, stir at 50-60°C to dissolve, then add 1-8 weight parts of modified graphene and 15-35 weight parts of KH550 modified diamond, perform ultrasonic dispersion in an ultrasonic instrument, and then dry and heat cure at 140-160°C to obtain a superhard composite material containing diamond and graphene.