Modified graphene oxide based on wet chemical modification and preparation method thereof

Abstract

The invention belongs to the technical field of functional materials, and particularly relates to modified graphene oxide based on wet chemical modification and a preparation method thereof. The preparation method of the modified graphene oxide based on wet chemical modification comprises the following steps: S1, carrying out thiol-ene click reaction on graphene oxide to obtain graphene oxide containing mesopores; and S2, carrying out alkynylation on the graphene oxide containing mesopores to obtain alkynylated graphene oxide, and then carrying out azide-alkyne click reaction on the alkynylated graphene oxide and azidation POSS (Polyhedral Oligomeric Silsesquioxane) to obtain the modified graphene oxide based on wet chemical modification. The modified graphene oxide with a specific space structure is prepared, the specific surface area of the material can be effectively increased, and the stability in a high-temperature environment is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and in particular relates to modified graphene oxide based on wet chemical modification and a preparation method thereof. Background Art

[0002] Graphene is a two-dimensional nanomaterial with a honeycomb-like six-membered ring planar network structure. Its unique structural characteristics give graphene excellent mechanical strength, chemical stability, high specific surface area, electrical and thermal conductivity. Therefore, graphene has shown broad application prospects in energy, materials, health, and the environment. Graphene oxide is produced by introducing covalent CO bonds into graphene, which consists of a hexagonal carbon network and sp 2 、sp 3 Hybridized carbon nanomaterials possess a unique quasi-two-dimensional layered structure. They contain numerous oxygen-containing groups, such as carboxyl and hydroxyl groups. These functional groups impart excellent reactivity and hydrophilicity to graphene oxide, while also providing numerous active sites for attaching other molecular structures and functional groups. This allows for easy functionalization with high controllability. Appropriate surface functionalization of graphene oxide can prevent its aggregation during reduction. This functional modification not only maintains the excellent properties of graphene but also introduces new surface functional groups, imparting novel surface properties.

[0003] A Chinese patent (publication number CN108707236B) discloses a method for preparing graphene oxide grafted with a fluoropolymer by click chemistry, comprising: (1) preparing graphene oxide using a modified Hummer's method; (2) alkynylation of the graphene oxide; (3) azidation of the fluoropolymer; and (4) synthesizing the fluoropolymer grafted with graphene oxide by click chemistry. This invention significantly improves the grafting rate, has a simple preparation process, and is suitable for industrial production. The material prepared by this invention has the characteristics of high tensile strength, good thermal stability, and high mechanical strength. However, the modified graphene oxide prepared by click chemistry in the prior art has problems such as a need to improve its specific surface area and insufficient thermal stability. In addition, it is impossible to control the spatial structure, which affects its further application.

[0004] Therefore, how to design the active groups in graphene oxide, treat different groups of graphene oxide through different click chemistry reactions, prepare modified graphene oxide with a specific spatial structure, effectively increase the specific surface area, and obtain good thermal stability has become a direction that needs to be studied. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a modified graphene oxide based on wet chemical modification and a preparation method thereof. The present invention selects carboxyl-rich graphene oxide as a raw material, utilizes double bonds and a thiol-ene click reaction to carry out a thiol-ene click reaction, and then carries out an azide-alkyne click reaction with an azidated POSS after alkynylation of the carboxyl group to prepare a modified graphene oxide with a specific spatial structure, which can effectively increase the specific surface area of ​​the material and improve the stability in a high-temperature environment.

[0006] The technical solutions of the present invention are as follows: The first aspect of the present invention provides a method for preparing modified graphene oxide based on wet chemical modification, comprising the following steps: S1: subjecting graphene oxide to a thiol-ene click reaction to obtain mesoporous graphene oxide; S2: alkynylate the mesoporous graphene oxide to obtain alkynylated graphene oxide, and then perform an azide-alkyne click reaction with azidated POSS to obtain modified graphene oxide based on wet chemical modification.

[0007] As a preferred technical solution of the present invention, the thiol-ene click reaction step includes: dispersing 1 to 3 parts of graphene oxide in 400 to 500 parts of N,N-dimethylformamide to form a dispersion, adding 0.04 to 0.08 parts of azobisisobutyronitrile and 2 to 6 parts of mercapto mesoporous silica under nitrogen atmosphere for heating reaction to obtain mesoporous graphene oxide.

[0008] As a preferred solution, the weight proportion of the graphene oxide in the present invention can be 1 part, 1.5 parts, 2 parts, 2.5 parts or 3 parts.

[0009] As a preferred solution, the weight proportion of the azobisisobutyronitrile in the present invention can be 0.04 parts, 0.05 parts, 0.06 parts, 0.07 parts or 0.08 parts, etc.

[0010] As a preferred solution, the weight proportion of the mercapto mesoporous silica in the present invention can be 2 parts, 3 parts, 4 parts, 5 parts or 6 parts.

[0011] As a preferred technical solution of the present invention, the conditions of the heating reaction include: reacting at 70-80°C for 10-12 hours, cooling to room temperature, filtering, washing with water, and freeze-drying.

[0012] As a preferred technical solution of the present invention, the preparation method of the mercapto mesoporous silica comprises: mixing 200-250 parts of anhydrous ethanol and 200-250 parts of deionized water, adding 6-10 parts of tetraethyl silicate, 3-5 parts of 3-mercaptopropyltrimethoxysilane, 0.6-0.8 parts of ammonia water and 0.2-0.6 parts of hexadecyltrimethylammonium bromide in sequence, stirring for 8-10 hours, centrifuging, washing with water, and drying to obtain mercapto mesoporous silica.

[0013] As a preferred solution, the weight proportion of the tetraethyl silicate in the present invention can be 6 parts, 7 parts, 8 parts, 9 parts or 10 parts.

[0014] As a preferred solution, the weight proportion of the 3-mercaptopropyltrimethoxysilane in the present invention can be 3 parts, 3.5 parts, 4 parts, 4.5 parts or 5 parts.

[0015] As a preferred solution, the weight proportion of the ammonia water in the present invention can be 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts or 0.8 parts, etc.

[0016] As a preferred solution, the weight proportion of the hexadecyltrimethylammonium bromide in the present invention can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts or 0.6 parts, etc.

[0017] As a preferred technical solution of the present invention, the graphene oxide is carboxylated graphene oxide with a sheet diameter of 0.5-5 μm and a thickness of 0.8-1.2 nm.

[0018] The present invention first uses tetraethyl orthosilicate and 3-mercaptopropyltrimethoxysilane as dual silicon sources, uses hexadecyltrimethylammonium bromide as a template, and uses ammonia water as a catalyst. After co-hydrolysis / condensation of mercaptosilane and tetraethyl orthosilicate, mercapto mesoporous silica with a high specific surface area is prepared. At the same time, due to the large number of double bonds in graphene oxide, these double bonds can serve as functionalization reaction active sites and can directly undergo a thiol-ene click reaction with mercapto groups to achieve functional modification of graphene oxide. Therefore, under the initiation of azobisisobutyronitrile, the mercapto mesoporous silica is bonded to the graphene oxide through a click reaction, thereby obtaining mesoporous graphene oxide.

[0019] As a preferred technical solution of the present invention, the preparation method of the azidated POSS comprises: adding 8 to 10 parts of chloropropyl POSS and 2.4 to 2.8 parts of sodium azide to a mixed solution of 180 to 200 parts of tetrahydrofuran and 500 to 520 parts of N,N-dimethylformamide, performing an azidation treatment to obtain the azidated POSS.

[0020] As a preferred solution, the weight proportions of the chloropropyl POSS in the present invention can be 8 parts, 8.5 parts, 9 parts, 9.5 parts or 10 parts, etc.

[0021] As a preferred solution, the weight proportion of sodium azide in the present invention can be 2.4 parts, 2.5 parts, 2.6 parts, 2.7 parts or 2.8 parts, etc.

[0022] As a preferred embodiment, the conditions of the azidation treatment include: placing in a nitrogen atmosphere, reacting at 60-70°C for 20-24 hours, cooling to room temperature, then adding 480-500 parts of dichloromethane and stirring for 10-12 minutes, then adding 900-1000 parts of deionized water and stirring for 30-40 minutes, standing to separate the layers, separating the dichloromethane layer, washing with water, drying, rotary evaporation, and separation by chromatography column.

[0023] As a preferred solution, the alkynylation step comprises: adding 1 to 3 parts of the mesoporous graphene oxide to 400 to 500 parts of N,N-dimethylformamide, ultrasonically dispersing the mixture, adding 1.2 to 1.8 parts of propargyl alcohol, and stirring evenly; then adding 8 to 10 parts of N,N'-dicyclohexylcarbodiimide and 3 to 5 parts of 4-dimethylaminopyridine; reacting the mixture at 24 to 26°C for 20 to 24 hours; centrifuging the mixture, washing the mixture with N,N-dimethylformamide, and vacuum drying the mixture to obtain alkynylated graphene oxide.

[0024] As a preferred embodiment, the conditions of the azide-alkyne click reaction include: adding 1 to 3 parts of alkyned graphene oxide and 6 to 10 parts of azidated POSS to 80 to 100 parts of N,N-dimethylformamide, controlling the temperature at 2 to 4°C under a nitrogen atmosphere, sequentially adding 1.6 to 1.8 parts of cuprous bromide and 2.4 to 2.8 parts of pentamethyldiethylenetriamine, stirring and mixing, reacting at 24 to 28°C for 40 to 48 hours, centrifuging, and vacuum drying to obtain modified graphene oxide based on wet chemical modification.

[0025] The invention uses chloropropyl POSS as a raw material and converts it into azidated POSS by reacting with sodium azide; at the same time, the edges of the mesoporous graphene oxide have carboxyl groups, and a simple esterification reaction between propargyl alcohol and graphene oxide is used to achieve alkynylation of the graphene oxide; finally, the azidated POSS and alkyned graphene oxide are subjected to an azide-alkyne click reaction, and the POSS is grafted onto the edge of the graphene oxide material to obtain modified graphene oxide based on wet chemical modification.

[0026] The second aspect of the present invention provides a modified graphene oxide based on wet chemical modification, which is prepared by the method described in the first aspect.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses carboxylated graphene oxide as a raw material, first combines mesoporous silica with double bonds through a thiol-ene click reaction, then uses carboxyl groups to alkyne the graphene and undergoes an azide-alkyne click reaction with azidated POSS. Since the carboxyl groups of carboxylated graphene oxide are mainly concentrated at the edge of the material and the double bonds are distributed on the surface of the material, mesoporous silica and POSS can be grafted at different positions of the graphene oxide through different click chemical reactions to prepare modified graphene oxide with a specific spatial structure. At the same time, the introduced mesoporous silica and POSS act synergistically to effectively increase the specific surface area of ​​the material and increase the thermal stability.

[0028] (2) The present invention introduces mercapto mesoporous silica into graphene oxide through thiol-ene click reaction. On the one hand, mercapto mesoporous silica has a regular pore structure, which can significantly increase the total pore volume of the composite material. At the same time, the mesoporous structure of silica and the interlayer pores of graphene oxide form hierarchical pores, and the combined effect increases the specific surface area of ​​the material. On the other hand, the skeleton structure of mesoporous silica blocks heat transfer, reduces the surface area of ​​graphene oxide oxygen-containing groups exposed to high temperature environment, delays the thermal degradation process, and thus improves the thermal stability of the material.

[0029] (3) The present invention grafts POSS onto the edge of graphene oxide material through an azide-alkyne click reaction. The rigid cage structure of POSS introduces micropores / mesopores on the surface of graphene oxide, thereby increasing the total pore volume of the material and effectively increasing the specific surface area. In addition, the bond energy of the Si-O bond introduced by POSS is much higher than that of the CC bond, which can maintain the skeleton structure of the material at high temperatures. The thermal stability of graphene oxide can be improved through the Si-O-Si skeleton. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 Schematic diagram of the thiol-ene click reaction of Example 1 of the present invention.

[0032] Figure 2 Schematic diagram of the alkynylation reaction of Example 1 of the present invention.

[0033] Figure 3 Schematic diagram of the azide-alkyne click reaction of Example 1 of the present invention. DETAILED DESCRIPTION

[0034] For the convenience of understanding the present invention, the present invention is given below with examples. It should be understood by those skilled in the art that the examples are only for the purpose of helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0035] The sources of some components in the Examples and Comparative Examples are as follows: Commercially available graphene oxide, product number G476611, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Commercially available carboxylated graphene oxide, product number XF004, was purchased from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.; N,N-dimethylformamide, CAS No. 68-12-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Azobisisobutyronitrile, CAS No. 78-67-1, was purchased from Sinopharm Chemical Reagent Co., Ltd. Tetraethyl silicate, CAS No. 78-10-4, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; 3-Mercaptopropyltrimethoxysilane, CAS No. 4420-74-0, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Ammonia water, CAS No. 1336-21-6, was purchased from Sinopharm Chemical Reagent Co., Ltd. Hexadecyltrimethylammonium bromide, CAS No. 57-09-0, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Chloropropyl POSS, product number O140428, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Sodium azide, CAS No. 26628-22-8, was purchased from Sinopharm Chemical Reagent Co., Ltd. Tetrahydrofuran, CAS No. 109-99-9, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Dichloromethane, CAS No. 75-09-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Propargyl alcohol, CAS No. 107-19-7, was purchased from Sinopharm Chemical Reagent Co., Ltd. N,N'-Dicyclohexylcarbodiimide, CAS No. 538-75-0, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; 4-Dimethylaminopyridine, CAS No. 1122-58-3, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Cuprous bromide, CAS No. 7787-70-4, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Pentamethyldiethylenetriamine, CAS number 3030-47-5, was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0036] Example 1 This embodiment provides a method for preparing modified graphene oxide based on wet chemical modification, comprising the following steps: S1: Disperse 3 parts by weight of carboxylated graphene oxide (Product No. XF004, 2 μm flake diameter, 1 nm thickness) in 500 parts of N,N-dimethylformamide to form a dispersion. Add 0.08 parts of azobisisobutyronitrile and 6 parts of mercapto-mesoporous silica under a nitrogen atmosphere. React at 80°C for 10 h. Cool to room temperature, filter, wash with water, and freeze-dry to obtain mesoporous graphene oxide. S2: In parts by weight, 3 parts of the mesoporous graphene oxide are added to 500 parts of N,N-dimethylformamide and ultrasonically dispersed, and then 1.8 parts of propargyl alcohol are added and stirred evenly, and then 10 parts of N,N'-dicyclohexylcarbodiimide and 5 parts of 4-dimethylaminopyridine are added, and the mixture is reacted at 26°C for 20 hours, centrifuged, washed with N,N-dimethylformamide, and vacuum dried to obtain alkyne-modified graphene oxide; 3 parts of alkyne-modified graphene oxide and 10 parts of azidated POSS are added to 100 parts of N,N-dimethylformamide, and 1.8 parts of cuprous bromide and 2.8 parts of pentamethyldiethylenetriamine are added in sequence under a nitrogen atmosphere at a temperature of 4°C, and the mixture is stirred and mixed, and the mixture is reacted at 28°C for 40 hours, centrifuged, and vacuum dried to obtain modified graphene oxide based on wet chemical modification.

[0037] Preparation of the mercapto mesoporous silica: In parts by weight, 250 parts of anhydrous ethanol and 250 parts of deionized water are mixed, and 10 parts of tetraethyl silicate, 5 parts of 3-mercaptopropyltrimethoxysilane, 0.8 parts of ammonia water and 0.6 parts of hexadecyltrimethylammonium bromide are added in sequence, and stirred for 10 hours, centrifuged, washed with water, and dried to obtain mercapto mesoporous silica.

[0038] The preparation of the azidated POSS is as follows: 10 parts of chloropropyl POSS and 2.8 parts of sodium azide are added to a mixture of 200 parts of tetrahydrofuran and 500 parts of N,N-dimethylformamide, placed in a nitrogen atmosphere, reacted at 70° C. for 20 hours, cooled to room temperature, then added with 500 parts of dichloromethane and stirred for 12 minutes, then added with 1000 parts of deionized water and stirred for 40 minutes, allowed to stand for stratification, the dichloromethane layer is separated, washed with water, dried, rotary evaporated, and separated by a chromatography column to obtain the azidated POSS.

[0039] Example 2 This embodiment provides a method for preparing modified graphene oxide based on wet chemical modification, comprising the following steps: S1: Disperse 1 part carboxylated graphene oxide (Product No. XF004, 2 μm flake diameter, 1 nm thickness) in 400 parts N,N-dimethylformamide to form a dispersion. Add 0.04 parts azobisisobutyronitrile and 2 parts mercapto-mesoporous silica under nitrogen atmosphere. React at 70°C for 12 h. Cool to room temperature, filter, wash with water, and freeze-dry to obtain mesoporous graphene oxide. S2: In parts by weight, 1 part of the mesoporous graphene oxide is added to 400 parts of N,N-dimethylformamide and ultrasonically dispersed, then 1.2 parts of propargyl alcohol are added and stirred evenly, and then 8 parts of N,N'-dicyclohexylcarbodiimide and 3 parts of 4-dimethylaminopyridine are added, and the mixture is reacted at 24°C for 24 hours, centrifuged, washed with N,N-dimethylformamide, and vacuum dried to obtain alkyne-modified graphene oxide; 1 part of alkyne-modified graphene oxide and 6 parts of azidated POSS are added to 80 parts of N,N-dimethylformamide, and 1.6 parts of cuprous bromide and 2.4 parts of pentamethyldiethylenetriamine are added in sequence while controlling the temperature at 2°C under a nitrogen atmosphere, and the mixture is stirred and mixed, and the mixture is reacted at 24°C for 48 hours, centrifuged, and vacuum dried to obtain modified graphene oxide based on wet chemical modification.

[0040] Preparation of the mercapto mesoporous silica: In parts by weight, 200 parts of anhydrous ethanol and 200 parts of deionized water are mixed, 6 parts of tetraethyl silicate, 3 parts of 3-mercaptopropyltrimethoxysilane, 0.6 parts of ammonia water and 0.2 parts of hexadecyltrimethylammonium bromide are added in sequence, and the mixture is stirred for 8 hours, centrifuged, washed with water, and dried to obtain mercapto mesoporous silica.

[0041] The preparation of the azidated POSS is as follows: 8 parts of chloropropyl POSS and 2.4 parts of sodium azide are added to a mixture of 180 parts of tetrahydrofuran and 520 parts of N,N-dimethylformamide, placed in a nitrogen atmosphere, reacted at 60° C. for 24 hours, cooled to room temperature, then added with 480 parts of dichloromethane and stirred for 12 minutes, then added with 900 parts of deionized water and stirred for 40 minutes, allowed to stand for stratification, the dichloromethane layer is separated, washed with water, dried, rotary evaporated, and separated by a chromatography column to obtain the azidated POSS.

[0042] Example 3 This embodiment provides a method for preparing modified graphene oxide based on wet chemical modification, comprising the following steps: S1: Disperse 2 parts by weight of carboxylated graphene oxide (Product No. XF004, 2 μm flake diameter, 1 nm thickness) in 450 parts of N,N-dimethylformamide to form a dispersion. Add 0.06 parts of azobisisobutyronitrile and 4 parts of mercapto-mesoporous silica under a nitrogen atmosphere. React at 75°C for 11 hours, cool to room temperature, filter, wash with water, and freeze-dry to obtain mesoporous graphene oxide. S2: In parts by weight, 2 parts of the mesoporous graphene oxide are added to 450 parts of N,N-dimethylformamide and ultrasonically dispersed, and then 1.4 parts of propargyl alcohol are added and stirred evenly, followed by adding 9 parts of N,N'-dicyclohexylcarbodiimide and 4 parts of 4-dimethylaminopyridine, reacting at 25°C for 22 hours, centrifuging, washing with N,N-dimethylformamide, and vacuum drying to obtain alkyne-modified graphene oxide; 2 parts of alkyne-modified graphene oxide and 8 parts of azidated POSS are added to 90 parts of N,N-dimethylformamide, and 1.7 parts of cuprous bromide and 2.6 parts of pentamethyldiethylenetriamine are added in sequence while controlling the temperature to 3°C under a nitrogen atmosphere, and stirred and mixed, and reacting at 25°C for 45 hours, centrifuging, and vacuum drying to obtain modified graphene oxide based on wet chemical modification.

[0043] Preparation of the mercapto mesoporous silica: In parts by weight, 220 parts of anhydrous ethanol and 220 parts of deionized water are mixed, and 8 parts of tetraethyl silicate, 4 parts of 3-mercaptopropyltrimethoxysilane, 0.7 parts of ammonia water and 0.4 parts of hexadecyltrimethylammonium bromide are added in sequence, and stirred for 9 hours. The mixture is centrifuged, washed with water and dried to obtain the mercapto mesoporous silica.

[0044] Preparation of the azidated POSS: In parts by weight, 9 parts of chloropropyl POSS and 2.6 parts of sodium azide are added to a mixture of 190 parts of tetrahydrofuran and 510 parts of N,N-dimethylformamide, placed in a nitrogen atmosphere, reacted at 65° C. for 22 hours, cooled to room temperature, then added 490 parts of dichloromethane and stirred for 11 minutes, then added 950 parts of deionized water and stirred for 35 minutes, allowed to stand and separate, the dichloromethane layer is separated, washed with water, dried, rotary evaporated, and separated by a chromatography column to obtain the azidated POSS.

[0045] Comparative Example 1 This comparative example provides a method for preparing modified graphene oxide, comprising the following steps: S1: In parts by weight, 10 parts of chloropropyl POSS and 2.8 parts of sodium azide are added to a mixture of 200 parts of tetrahydrofuran and 500 parts of N,N-dimethylformamide, placed in a nitrogen atmosphere, reacted at 70°C for 20 hours, cooled to room temperature, then added 500 parts of dichloromethane and stirred for 12 minutes, then added 1000 parts of deionized water and stirred for 40 minutes, allowed to stand and separate, the dichloromethane layer is separated, washed with water, dried, rotary evaporated, and separated by chromatography column to obtain azidated POSS.

[0046] S2: In parts by weight, 3 parts of carboxylated graphene oxide (Product No. XF004, flake diameter of 2 μm, thickness of 1 nm) were added to 500 parts of N,N-dimethylformamide and ultrasonically dispersed, and then 1.8 parts of propargyl alcohol were added and stirred evenly. Then, 10 parts of N,N'-dicyclohexylcarbodiimide and 5 parts of 4-dimethylaminopyridine were added, and the mixture was reacted at 26°C for 20 hours, centrifuged, washed with N,N-dimethylformamide, and vacuum dried to obtain alkyne-modified graphene oxide; 3 parts of alkyne-modified graphene oxide and 10 parts of azidated POSS were added to 100 parts of N,N-dimethylformamide, and 1.8 parts of cuprous bromide and 2.8 parts of pentamethyldiethylenetriamine were added in sequence under a nitrogen atmosphere at a temperature of 4°C, and the mixture was stirred and mixed. The mixture was reacted at 28°C for 40 hours, centrifuged, and vacuum dried to obtain modified graphene oxide based on wet chemical modification.

[0047] Comparative Example 2 This comparative example provides a method for preparing modified graphene oxide, comprising the following steps: S1: In parts by weight, 250 parts of anhydrous ethanol and 250 parts of deionized water were mixed, and 10 parts of tetraethyl silicate, 5 parts of 3-mercaptopropyltrimethoxysilane, 0.8 parts of ammonia water and 0.6 parts of hexadecyltrimethylammonium bromide were added in sequence, and stirred for 10 hours. The mixture was centrifuged, washed with water and dried to obtain mercapto mesoporous silica.

[0048] S2: Disperse 3 parts by weight of carboxylated graphene oxide (Product No. XF004, 2 μm flake diameter, 1 nm thickness) in 500 parts of N,N-dimethylformamide to form a dispersion. Add 0.08 parts of azobisisobutyronitrile and 6 parts of mercapto mesoporous silica under a nitrogen atmosphere. React at 80°C for 10 h. Cool to room temperature, filter, wash with water, and freeze-dry to obtain modified graphene oxide. Comparative Example 3 The difference between this comparative example and Example 1 is that graphene oxide (Article No. G476611) is used instead of carboxylated graphene oxide (Article No. XF004).

[0049] The performance of graphene oxide was tested, and the test method was as follows: (1) Specific surface area test: The test was conducted in accordance with the requirements of GB / T 42310-2023 Nanotechnology graphene powder - Determination of specific surface area - Argon adsorption static volumetric method.

[0050] (2) Thermal stability test: The prepared graphene oxide was subjected to thermogravimetric analysis test: the test sample mass was about 10 mg, the test temperature range was 25℃~300℃, the heating rate was 5℃ / min, the nitrogen atmosphere, and the gas flow rate was about 200mL / min; the thermal stability was expressed by the weight loss rate at 250℃.

[0051] The above performance test data is shown in Table 1.

[0052] Table 1 Performance test results Specific surface area (m² / g) 250℃ weight loss rate (%) Example 1 452 5.1 Example 2 438 6.3 Example 3 445 5.6 Comparative Example 1 341 20.5 Comparative Example 2 356 19.2 Comparative Example 3 402 9.4 Commercially available carboxylated graphene oxide 195 50.2 From the above content, it can be seen that by selecting carboxyl-rich graphene oxide as raw material, using double bonds and thiol-ene click reaction to carry out thiol-ene click reaction, and then carrying out alkynylation through carboxyl groups and then carrying out azide-alkyne click reaction with azidated POSS to prepare modified graphene oxide with a specific spatial structure, which can effectively increase the specific surface area of ​​the material and improve the stability in high temperature environment.

[0053] Compared with Example 1, the modified graphene oxide in Comparative Example 1 did not undergo a thiol-ene click reaction and lacked the effect of thiol mesoporous silica, so the specific surface area was reduced and the thermal stability deteriorated; compared with Example 1, the modified graphene oxide in Comparative Example 2 did not undergo an azide-alkyne click reaction and lacked the effect of POSS, so the specific surface area was reduced and the thermal stability deteriorated; compared with Example 1, Comparative Example 3 used graphene oxide (Article No. G476611) instead of carboxylated graphene oxide (Article No. XF004). Since the commercially available graphene oxide has a small number of carboxyl groups, the subsequent modification effect is poor, so the specific surface area is reduced and the thermal stability deteriorates.

Claims

1. A method for preparing modified graphene oxide based on wet chemical modification, characterized in that, include Follow these steps: S1: subjecting graphene oxide to a thiol-ene click reaction to obtain mesoporous graphene oxide; S2: alkynylate the mesoporous graphene oxide to obtain alkynylated graphene oxide, and then perform an azide-alkyne click reaction with azidated POSS to obtain modified graphene oxide based on wet chemical modification.

2. A method for preparing modified graphene oxide based on wet chemical modification according to claim 1, characterized in that, The thiol-ene click reaction step includes: dispersing 1 to 3 parts of graphene oxide in 400 to 500 parts of N,N-dimethylformamide to form a dispersion, adding 0.04 to 0.08 parts of azobisisobutyronitrile and 2 to 6 parts of mercapto mesoporous silica under nitrogen atmosphere for heating reaction to obtain mesoporous graphene oxide.

3. A method for preparing modified graphene oxide based on wet chemical modification according to claim 2, characterized in that, The heating reaction conditions include: reacting at 70-80° C. for 10-12 hours, cooling to room temperature, filtering, washing with water, and freeze-drying.

4. A method for preparing modified graphene oxide based on wet chemical modification according to claim 2, characterized in that, The preparation method of the mercapto mesoporous silica comprises: mixing 200-250 parts of anhydrous ethanol and 200-250 parts of deionized water, adding 6-10 parts of tetraethyl silicate, 3-5 parts of 3-mercaptopropyltrimethoxysilane, 0.6-0.8 parts of ammonia water and 0.2-0.6 parts of hexadecyltrimethylammonium bromide in sequence, stirring for 8-10 hours, centrifuging, washing with water and drying to obtain the mercapto mesoporous silica.

5. A method for preparing modified graphene oxide based on wet chemical modification according to claim 2, characterized in that, The graphene oxide is carboxylated graphene oxide with a sheet diameter of 0.5-5 μm and a thickness of 0.8-1.2 nm.

6. The method for preparing modified graphene oxide based on wet chemical modification according to claim 1, wherein: The preparation method of the azidated POSS comprises: adding 8 to 10 parts of chloropropyl POSS and 2.4 to 2.8 parts of sodium azide to a mixed solution of 180 to 200 parts of tetrahydrofuran and 500 to 520 parts of N,N-dimethylformamide, performing an azidation treatment, and obtaining the azidated POSS.

7. The method for preparing modified graphene oxide based on wet chemical modification according to claim 6, wherein: The conditions of the azidation treatment include: placing in a nitrogen atmosphere, reacting at 60-70° C. for 20-24 hours, cooling to room temperature, then adding 480-500 parts of dichloromethane and stirring for 10-12 minutes, then adding 900-1000 parts of deionized water and stirring for 30-40 minutes, standing to separate the layers, separating the dichloromethane layer, washing with water, drying, rotary evaporation, and separation by chromatography column.

8. The method for preparing modified graphene oxide based on wet chemical modification according to claim 1, wherein: The alkynylation step includes: adding 1 to 3 parts of the mesoporous graphene oxide to 400 to 500 parts of N,N-dimethylformamide, ultrasonically dispersing the mixture, adding 1.2 to 1.8 parts of propargyl alcohol, stirring the mixture evenly, adding 8 to 10 parts of N,N'-dicyclohexylcarbodiimide and 3 to 5 parts of 4-dimethylaminopyridine, reacting the mixture at 24 to 26°C for 20 to 24 hours, centrifuging the mixture, washing the mixture with N,N-dimethylformamide, and vacuum drying the mixture to obtain alkynylated graphene oxide.

9. The method for preparing modified graphene oxide based on wet chemical modification according to claim 1, wherein: The conditions of the azide-alkyne click reaction include: adding 1-3 parts of alkynylated graphene oxide and 6-10 parts of azidated POSS to 80-100 parts of N,N-dimethylformamide, controlling the temperature at 2-4°C under a nitrogen atmosphere, sequentially adding 1.6-1.8 parts of cuprous bromide and 2.4-2.8 parts of pentamethyldiethylenetriamine, stirring and mixing, reacting at 24-28°C for 40-48 hours, centrifuging, and vacuum drying to obtain modified graphene oxide based on wet chemical modification.

10. A modified graphene oxide based on wet chemical modification, characterized in that, Prepared according to the method according to any one of claims 1 to 9.

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