A thin film containing modified graphene and its preparation method
By modifying the preparation method of graphene films and utilizing the grafting reaction of silane coupling agents and azobenzene compounds, combined with electrostatic assembly technology, the problems of weak light-controlled switching function and weak interfacial bonding of graphene films were solved, and the photoresponse deformation and high barrier performance were improved, thus expanding its application scenarios.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TAIXING ZHIFU DISPLAY TECH CO LTD
- Filing Date
- 2025-09-11
- Publication Date
- 2026-06-02
AI Technical Summary
Existing graphene films lack light-controlled switching functionality in smart packaging and flexible electronics, and their weak interfacial bonding leads to unstable performance, limiting their application scenarios.
Modified graphene films were prepared by grafting composite graphene powder with azobenzene compounds containing silanes and silanes containing double bonds. The films were then deformed under ultraviolet and visible light. Modified attapulgite was then electrostatically assembled with graphene oxide to form a two-dimensional sheet-supported one-dimensional rod structure, which improved dispersibility and mechanical properties.
This technology enables dynamic control of film deformation under illumination, improves the film's light response speed and high barrier properties, expands its application in smart packaging and flexible electronics, and enhances the film's mechanical properties and gas barrier capabilities.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer composite materials technology, and relates to a thin film containing modified graphene and its preparation method. Background Technology
[0002] Graphene, with its single-atom-layer two-dimensional crystal structure, exhibits excellent electrical, mechanical, and thermal conductivity properties, making it an ideal filler for constructing next-generation high-performance functional films. However, graphene's surface is chemically inert and lacks active functional groups, resulting in weak interfacial bonding with commonly used matrix materials such as polymers and metal oxides. This often leads to problems like interfacial delamination and performance instability in the prepared composite films. These defects significantly limit the practical application of graphene in the thin film field. Therefore, modifying graphene to improve its dispersibility and interfacial compatibility has become a key prerequisite for promoting the industrialization of graphene-based thin films.
[0003] Chinese invention patent application CN106832534B discloses a high-barrier double-bond functionalized graphene oxide / polyethylene film and its preparation method. The double-bond functionalized graphene oxide / polyethylene film contains double-bond functionalized graphene oxide components. The specific preparation method is as follows: graphene oxide modified with double-bond functional groups is mixed with low-density polyethylene resin in a certain ratio, and the graphene oxide / polyethylene composite film is prepared by a longitudinal and then transverse sequential stretching process. The prepared double-bond functionalized graphene oxide / polyethylene film has a simple preparation process, high barrier performance, and adjustable thickness, making it suitable for large-area industrial preparation.
[0004] The thin film in the above scheme has a relatively simple function. The design of double bond functionalized graphene oxide is only aimed at barrier properties. However, in some fields such as smart packaging or flexible electronics, the thin film cannot adjust its state according to changes in light conditions and does not have light-controlled switching function. It lacks the possibility of application in dynamic control in high-end fields, which limits the application scenarios of the thin film. Summary of the Invention
[0005] The purpose of this invention is to provide a film containing modified graphene and its preparation method. By grafting composite graphene powder with azobenzene compounds containing silane and silane containing double bonds, and then melt-blending it with a matrix and casting it into a film, the film has the properties of photoresponsive deformation and high barrier properties.
[0006] The objective of this invention can be achieved through the following technical solutions:
[0007] A method for preparing a thin film containing modified graphene includes the following steps:
[0008] Step 1: Graft a silane containing an isocyanate group onto an azobenzene containing an amino group to obtain an azobenzene compound containing a silane.
[0009] Step 2: Attapulgite is modified with a silane coupling agent to obtain modified attapulgite. The modified attapulgite and graphene oxide are then combined by electrostatic assembly to obtain composite graphene powder.
[0010] Step 3: Graft the composite graphene powder with an azobenzene compound containing silane and a silane containing double bonds to obtain modified composite graphene powder, then melt-blend it with low-density polyethylene particles, and then cast it into a film through an extrusion casting machine to obtain a film containing modified graphene.
[0011] Furthermore, the specific preparation process of azobenzene compounds containing silanes is as follows:
[0012] A silane containing an isocyanate group and an azobenzene containing an amino group were added to a reaction vessel, followed by anhydrous tetrahydrofuran. The mixture was heated to 70-75°C under a nitrogen atmosphere and refluxed for 6-8 hours. Then, n-hexane was added, and the mixture was crystallized at -20°C for 24-26 hours. After filtration, an azobenzene compound containing a silane was obtained.
[0013] Furthermore, the silane containing the isocyanate group is one of propyltriethoxysilane, 3-isocyanopropyltrimethoxysilane, and propylmethyldimethoxysilane.
[0014] Furthermore, the amino-containing azobenzene is one of 4,4'-azodiphenylamine and 4-phenylazobenzene.
[0015] Furthermore, the specific preparation process of modified attapulgite is as follows:
[0016] The purified attapulgite, an 80 vol% aqueous ethanol solution, and an amino-containing silane coupling agent were added to a reaction vessel and stirred and refluxed at 80-90℃ for 3-4 hours. The mixture was then filtered, washed, freeze-dried, and pulverized to obtain modified attapulgite.
[0017] Furthermore, the specific preparation process of the composite graphene powder is as follows:
[0018] Graphene oxide, deionized water, and modified attapulgite were added to a reactor and ultrasonically dispersed for 1-2 hours. After self-assembly, the mixture was allowed to stand for 12-14 hours, filtered, washed, freeze-dried, and pulverized to obtain composite graphene powder.
[0019] Furthermore, the specific preparation process of the modified composite graphene powder is as follows:
[0020] Composite graphene powder and deionized water were added to a reaction vessel and ultrasonically dispersed for 60-70 min. A 0.2 mol / L solution of azobenzene compound containing silane and a silane containing double bonds were added and mixed evenly. The mixture was then refluxed at 70-80℃ for 24-26 h. After washing and drying, modified composite graphene powder was obtained.
[0021] Furthermore, the silane with the double bond is one of vinyltriisopropoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.
[0022] Furthermore, the ratio of composite graphene powder, deionized water, toluene solution of azobenzene compound containing silane, and silane containing double bonds is 10-20g: 6-8L: 3-5L: 1.0-1.8g.
[0023] Furthermore, the melt blending temperature is set to 150-200℃, and the rotation speed is set to 15-20 r / min.
[0024] Furthermore, the casting temperature is 140-190℃, and the film thickness is 60±2μm.
[0025] The beneficial effects of this invention are:
[0026] 1. This invention involves reacting and grafting composite graphene powder with azobenzene compounds containing silanes and silanes containing double bonds, followed by melt blending and casting with low-density polyethylene particles to obtain a film containing modified graphene. This allows the silicon-oxygen-containing azobenzene compounds to be uniformly dispersed in the film. Under ultraviolet light irradiation, azobenzene molecules transform into bent cis isomers. Isomerization leads to a decrease in the horizontal arrangement of azobenzene molecules and a change in intermolecular spacing, causing the film to bend towards light. Under visible light irradiation, azobenzene isomerizes from cis to trans, and the film material returns to its original shape. The one-dimensional rod-like structure and the two-dimensional sheet structure of graphene oxide form a "rod-sheet" synergistic reinforcement structure, preventing graphene oxide agglomeration and improving the dispersion of graphene oxide in the film matrix, thereby increasing the speed of light response and expanding the application of the film in fields such as smart packaging or flexible electronics.
[0027] 2. This invention first modifies attapulgite with an amino-containing silane coupling agent to make it contain amino groups, and then utilizes the protonation of the amino groups on the modified attapulgite in an aqueous phase to form positively charged -NH3. +The carboxyl and hydroxyl groups on the surface of graphene oxide readily ionize into hydrogen ions in the aqueous phase, giving the graphene oxide surface a strong negative charge. Modified attapulgite is uniformly attached to the surface and edges of graphene oxide through electrostatic assembly, forming a composite structure of two-dimensional sheets supporting one-dimensional rods. This structure not only prevents graphene oxide from stacking and ensuring its uniform dispersion in the film matrix, but also reduces deformation when the film is stretched by external forces. Furthermore, the composite graphene powder is modified with silane containing double bonds, allowing the modified composite graphene powder to partially crosslink with the matrix during the melting process, thereby improving the mechanical properties of the film.
[0028] 3. The two-dimensional sheet structure of the composite graphene powder in this invention forms the first barrier in the low-density polyethylene matrix, which prolongs the permeation path of gas molecules. Attapulgite, through electrostatic assembly on the surface and between layers of graphene oxide, can further divide the permeation channels and synergistically improve the gas diffusion resistance. In addition, the aromatic ring of azobenzene has a hydrophobic structure, which further reduces the water contact angle and reduces the adsorption and diffusion of water molecules on the film surface. Furthermore, the good compatibility between azobenzene molecules and the matrix reduces the interfacial gap, further reduces the water and oxygen permeability, and improves the high barrier performance of the film. Detailed Implementation
[0029] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.
[0030] Example 1: This example provides a thin film containing modified graphene, prepared through the following steps:
[0031] S1: 25.5g of propyltriethoxysilane and 18.3g of 4-phenylazoaniline were added to a reaction vessel, followed by 135mL of anhydrous tetrahydrofuran. The mixture was heated to 72℃ under a nitrogen atmosphere and refluxed for 7h. The isocyanate group in propyltriethoxysilane reacted with the amino group in 4-phenylazoaniline to form a graft. 450mL of n-hexane was added, and the mixture was crystallized at -20℃ for 25h. After filtration, an azobenzene compound containing silane was obtained.
[0032] S2: 35g of purified attapulgite, 1.6L of 80vol% ethanol aqueous solution and 17g of 3-aminopropyltriethoxysilane were added to the reaction vessel and stirred and refluxed at 85℃ for 3.5h. The 3-aminopropyltriethoxysilane hydrolyzed and condensed with the silanol groups on the surface of the attapulgite. The mixture was filtered, and the filter cake was washed 4 times with distilled water and ethanol. It was then freeze-dried, pulverized and passed through a 60-mesh sieve to obtain modified attapulgite.
[0033] 15g of graphene oxide, 24L of deionized water, and 35g of modified attapulgite were added to a reactor and stirred until homogeneous. The mixture was then ultrasonically dispersed for 1.5h. After self-assembly was completed, the mixture was allowed to stand for 13h. The amino groups on the modified attapulgite were protonated in the aqueous phase to form positively charged -NH3 groups. + The carboxyl and hydroxyl groups on the surface of graphene oxide readily ionize into hydrogen ions in the aqueous phase, giving the graphene oxide surface a strong negative charge. Modified attapulgite is uniformly attached to the surface and edges of graphene oxide through electrostatic assembly, forming a composite structure of two-dimensional sheets supporting one-dimensional rods. After filtration, the filter cake is washed four times with deionized water, freeze-dried, pulverized, and passed through a 60-mesh sieve to obtain composite graphene powder.
[0034] S3: Add 15g of composite graphene powder and 7L of deionized water to a reaction vessel, and ultrasonically disperse for 65min. Add 4L of a 0.2mol / L toluene solution of azobenzene compounds containing silane and 1.4g of vinyltrimethoxysilane, mix well, and reflux at 75℃ for 25h. The silicon-oxygen bonds of vinyltrimethoxysilane and azobenzene compounds containing silane hydrolyze and react with hydroxyl groups on the composite graphene powder for grafting. Filter, wash the filter cake four times with ethanol and deionized water, and vacuum dry at 52℃ to constant weight to obtain modified composite graphene powder.
[0035] S4: 110g of dried low-density polyethylene granules and 3g of modified composite graphene powder were mechanically blended at high speed. The mixture was then melt-extruded and water-cooled to obtain composite granules through a twin-screw granulator. The screw temperature during melt blending was set to 175℃ and the rotation speed was set to 17r / min. The composite granules were then added to an extrusion casting machine. The screw temperature during casting was set to 165℃, and the film thickness was 60μm, resulting in a film containing modified graphene.
[0036] Example 2: This example provides a thin film containing modified graphene, prepared through the following steps:
[0037] S1: 20.5g of propyltriethoxysilane and 15.8g of 4-phenylazoaniline were added to a reaction vessel, followed by 120mL of anhydrous tetrahydrofuran. The mixture was heated to 70℃ under a nitrogen atmosphere and refluxed for 6h. The isocyanate group in propyltriethoxysilane reacted with the amino group in 4-phenylazoaniline to form a graft. 400mL of n-hexane was added, and the mixture was crystallized at -20℃ for 24h. After filtration, an azobenzene compound containing silane was obtained.
[0038] S2: 30g of purified attapulgite, 1.5L of 80vol% ethanol aqueous solution and 15g of 3-aminopropyltriethoxysilane were added to a reaction vessel and stirred and refluxed at 80℃ for 3h. The 3-aminopropyltriethoxysilane hydrolyzed and condensed with the silanol groups on the surface of the attapulgite. The mixture was filtered, and the filter cake was washed three times with distilled water and ethanol. It was then freeze-dried, pulverized and passed through a 60-mesh sieve to obtain modified attapulgite. 10g of graphene oxide, 23L of deionized water and 30g of modified attapulgite were added to a reaction vessel and stirred evenly. The mixture was ultrasonically dispersed for 1h. After self-assembly was completed, it was allowed to stand for 12h. The mixture was filtered, and the filter cake was washed three times with deionized water. It was then freeze-dried, pulverized and passed through a 60-mesh sieve to obtain composite graphene powder.
[0039] S3: Add 10g of composite graphene powder and 6L of deionized water to a reaction vessel, ultrasonically disperse for 60min, add 3L of a 0.2mol / L toluene solution of azobenzene compound containing silane and 1.0g of vinyltrimethoxysilane, mix well, reflux at 70℃ for 24h, filter, wash the filter cake three times with ethanol and deionized water, and vacuum dry at 50℃ to constant weight to obtain modified composite graphene powder.
[0040] S4: 100g of dried low-density polyethylene granules and 2g of modified composite graphene powder were mechanically blended at high speed. The mixture was then melt-extruded and water-cooled into pellets through a twin-screw granulator to obtain composite granules. The screw temperature during melt blending was set to 150℃ and the rotation speed was set to 15r / min. The composite granules were then added to an extrusion casting machine. The screw temperature during casting was set to 140℃, and the film thickness was 58μm to obtain a film containing modified graphene.
[0041] Example 3: This example provides a thin film containing modified graphene, prepared through the following steps:
[0042] S1: 30.5g of propyltriethoxysilane and 20.8g of 4-phenylazoaniline were added to a reaction vessel, followed by 150mL of anhydrous tetrahydrofuran. The mixture was heated to 75℃ under a nitrogen atmosphere and refluxed for 8h. The isocyanate group in propyltriethoxysilane reacted with the amino group in 4-phenylazoaniline to form a graft. 500mL of n-hexane was added, and the mixture was crystallized at -20℃ for 26h. After filtration, an azobenzene compound containing silane was obtained.
[0043] S2: 40g of purified attapulgite, 1.7L of 80vol% ethanol aqueous solution and 20g of 3-aminopropyltriethoxysilane were added to a reactor and stirred and refluxed at 90℃ for 4h. After filtration, the filter cake was washed 5 times with distilled water and ethanol, freeze-dried, pulverized and passed through a 60-mesh sieve to obtain modified attapulgite. 20g of graphene oxide, 25L of deionized water and 40g of modified attapulgite were added to a reactor and ultrasonically dispersed for 2h. After standing for 14h, the mixture was filtered, the filter cake was washed 5 times with deionized water, freeze-dried, pulverized and passed through a 60-mesh sieve to obtain composite graphene powder.
[0044] S3: Add 20g of composite graphene powder and 8L of deionized water to a reaction vessel, ultrasonically disperse for 70min, add 5L of a 0.2mol / L toluene solution of azobenzene compound containing silane and 1.8g of vinyltrimethoxysilane, reflux at 80℃ for 26h, filter, wash the filter cake 5 times with ethanol and deionized water, and vacuum dry at 55℃ to constant weight to obtain modified composite graphene powder.
[0045] S4: 120g of dried low-density polyethylene granules and 4g of modified composite graphene powder were mechanically blended at high speed. The mixture was then melt-extruded and water-cooled to obtain composite granules through a twin-screw granulator. The screw temperature during melt blending was set to 200℃ and the rotation speed was set to 20r / min. The composite granules were then added to an extrusion casting machine. The screw temperature during casting was set to 190℃, and the film thickness was 62μm, resulting in a film containing modified graphene.
[0046] Example 4: This example provides a film containing modified graphene. The difference from Example 1 is that 3-isocyanate-propyltrimethoxysilane is used instead of isocyanate-propyltriethoxysilane in step S1.
[0047] Example 5: This example provides a film containing modified graphene. The difference from Example 1 is that 4,4'-azodiphenylamine is used instead of 4-phenylazoaniline in step S1, and the amount is adjusted to 10g.
[0048] Example 6: This example provides a film containing modified graphene. The difference from Example 1 is that vinyltriisopropoxysilane is used instead of vinyltrimethoxysilane in step S3.
[0049] Comparative Example 1: This comparative example provides a film containing modified graphene. The difference from Example 1 is that in step S3, graphene oxide powder is used instead of composite graphene powder.
[0050] Comparative Example 2: This comparative example provides a film containing modified graphene, which differs from Example 1 in that vinyltrimethoxysilane is not added in step S3.
[0051] Comparative Example 3: This comparative example provides a film containing modified graphene. The difference from Example 1 is that in step S3, a toluene solution containing silane and azobenzene compounds with a concentration of 0.2 mol / L is not added, and the amount of vinyltrimethoxysilane is adjusted to 3-4 g.
[0052] The modified graphene-containing films prepared in Examples 1-6 and Comparative Examples 1-3 were subjected to performance testing:
[0053] UV-Vis response test: The modified graphene film was cut into strips of 11mm×2mm×0.01mm. One end of the film was held with tweezers and fixed on a platform to test the photodynamic motion of the film. After being irradiated with UV light and then with visible light, the film gradually returned to its original flat state. The time for the film to respond to UV light was calculated.
[0054] Mechanical property testing: Following GB / T 1040.1-2006 and GB / T 1040.3-2006 standards, the tensile properties of the films were tested using an electronic universal testing machine. The prepared films were cut into strips with a width of 15 mm and a length ≥ 150 mm. The sampling direction was parallel to the tensile direction of the film (orientation), and the tensile speed was set to 200 mm / min. Five samples were tested for each type of film, focusing on tensile strength and elongation at break, and the average value was taken as the test result.
[0055] Barrier performance test: In accordance with GB / T 1038.1-2022 standard, the oxygen transmission rate of the film was tested using a gas permeability tester. The film was dried in a desiccator for 48 hours and then tested at 23℃. Three samples of each film were measured and the average value was taken as the test result.
[0056] Referring to the GB / T 1037-2021 standard, the water vapor transmission rate of the film was tested using a water vapor transmission rate testing system. The sample was conditioned for 4 hours in a standard environment of 23℃ and 50%RH, and then tested under test conditions of 38℃ and 90%RH. Three samples were measured for each type of film, and the average value was taken as the test result.
[0057] The performance tests are shown in the table below:
[0058] Table 1 Performance Test Overview
[0059] project Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Ultraviolet light response time (s) 3 3 4 4 4 3 5 10 No response Tensile strength (MPa) 35.2 35.4 35.1 35.5 35.2 35.4 28.5 31.4 22.5 Elongation at break (%) 185 182 183 184 181 182 153 165 141 <![CDATA[Oxygen Permeability Coefficient (×10 -14 cm 3 ·cm / cm 2 ·s·Pa)]]> 3.98 3.97 3.95 3.96 3.98 3.95 4.84 4.91 5.15 <![CDATA[Water vapor permeability coefficient (×10 -15 g·cm / cm 2 ·s·Pa)]]> 3.54 3.57 3.53 3.56 3.55 3.57 4.47 4.52 5.04
[0060] As shown in Table 1, the UV response times of Examples 1-6 are all lower than those of Comparative Examples 1-3. This may be because when the azobenzene portion on the film surface is irradiated with UV light, the absorbance of the corresponding trans-azobenzene molecules decreases significantly. In the trans state, azobenzene has a rod-shaped molecular structure. When exposed to UV light, the molecules will transform into the bent cis isomer. Isomerization leads to a decrease in the horizontal arrangement order of azobenzene molecules and a change in the intermolecular spacing. The film material will generate uneven mechanical stress, thus bending towards light. When the film is irradiated with visible light, the absorbance of trans-azobenzene increases significantly within the corresponding wavelength range. Azobenzene isomerizes from cis to trans, and the film material returns to its original shape. The addition of vinyltrimethoxysilane can increase the compatibility of the modified composite graphene powder in the matrix, making its distribution more uniform, thereby achieving the UV-Vis light response phenomenon, improving the light response speed, and expanding the application of this film in fields such as smart packaging or flexible electronics.
[0061] As shown in Table 1, the tensile strength and elongation at break of Examples 1-6 are all greater than those of Comparative Examples 1-3. This indicates that the one-dimensional rod-like structure of attapulgite and the two-dimensional sheet structure of graphene oxide form a "rod-sheet" synergistic reinforcement structure, which can both prevent graphene oxide stacking and improve the tensile strength of the film. Vinyltrimethoxysilane combines with the hydroxyl groups of composite graphene through silicon-oxygen bonds. On the other hand, carbon-carbon double bonds can partially crosslink with the matrix during melt blending, improving the interfacial compatibility between graphene oxide and the matrix, thereby improving stress transfer efficiency and enhancing the mechanical strength of the film.
[0062] As shown in Table 1, the oxygen permeability and moisture permeability of Examples 1-6 are all lower than those of Comparative Examples 1-3. This may be because the two-dimensional sheet structure of graphene oxide forms the first barrier in the low-density polyethylene matrix, which prolongs the permeation path of gas molecules. The one-dimensional rod structure of attapulgite is interspersed between the sheets of graphene oxide, further dividing the permeation channels and synergistically improving the gas diffusion resistance. In addition, the aromatic ring of azobenzene is hydrophobic, which reduces the adsorption and diffusion of water molecules on the film surface. The good compatibility between azobenzene molecules and the matrix reduces the interfacial gap and further reduces the water and oxygen permeability, so that the film containing modified graphene has high barrier performance.
[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A method for preparing a thin film containing modified graphene, characterized in that, Includes the following steps: Step 1: Graft a silane containing an isocyanate group onto an azobenzene containing an amino group to obtain an azobenzene compound containing a silane. The silane containing the isocyanate group is one of propyltriethoxysilane, 3-isocyanopropyltrimethoxysilane, and propylmethyldimethoxysilane. The amino-containing azobenzene is one of 4,4'-azodiphenylamine and 4-phenylazobenzene; Step 2: Attapulgite is modified by silane coupling agent to obtain modified attapulgite. The modified attapulgite and graphene oxide are then combined by electrostatic assembly to obtain composite graphene powder. The specific preparation process of the modified attapulgite described in step two is as follows: The purified attapulgite, an 80 vol% aqueous ethanol solution, and an amino-containing silane coupling agent were added to a reaction vessel and stirred and refluxed at 80-90℃ for 3-4 hours. The mixture was then filtered, washed, freeze-dried, and pulverized to obtain modified attapulgite. Step 3: Graft the composite graphene powder with azobenzene compounds containing silane and silanes containing double bonds to obtain modified composite graphene powder, then melt-blend it with low-density polyethylene particles, and then cast it into a film through an extrusion casting machine to obtain a film containing modified graphene. The silane containing the double bond is one of vinyltriisopropoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.
2. The method for preparing a thin film containing modified graphene according to claim 1, characterized in that, The specific preparation process of the silane-containing azobenzene compound described in step one is as follows: A silane containing an isocyanate group and an azobenzene containing an amino group were added to a reaction vessel, followed by anhydrous tetrahydrofuran. The mixture was heated to 70-75°C under a nitrogen atmosphere and refluxed for 6-8 hours. Then, n-hexane was added, and the mixture was crystallized at -20°C for 24-26 hours. After filtration, an azobenzene compound containing a silane was obtained.
3. The method for preparing a thin film containing modified graphene according to claim 1, characterized in that, The specific preparation process of the composite graphene powder mentioned in step two is as follows: Graphene oxide, deionized water, and modified attapulgite were added to a reactor and ultrasonically dispersed for 1-2 hours. After self-assembly, the mixture was allowed to stand for 12-14 hours, filtered, washed, freeze-dried, and pulverized to obtain composite graphene powder.
4. The method for preparing a thin film containing modified graphene according to claim 1, characterized in that, The specific preparation process of the modified composite graphene powder in step three is as follows: Composite graphene powder and deionized water were added to a reaction vessel and ultrasonically dispersed for 60-70 min. A toluene solution containing silane-containing azobenzene compounds and silane containing double bonds were added at a concentration of 0.2 mol / L. The mixture was mixed evenly and refluxed at 70-80℃ for 24-26 h. The mixture was then washed and dried to obtain modified composite graphene powder.
5. The method for preparing a thin film containing modified graphene according to claim 4, characterized in that, The ratio of the composite graphene powder, deionized water, toluene solution of azobenzene compound containing silane, and silane containing double bonds is 10-20g: 6-8L: 3-5L: 1.0-1.8g.
6. The method for preparing a thin film containing modified graphene according to claim 1, characterized in that, The melt blending temperature is set to 150-200℃, the rotation speed is set to 15-20 r / min, the casting temperature is 140-190℃, and the film thickness is 60±2μm.
7. A thin film containing modified graphene, characterized in that, The film containing modified graphene was prepared by any one of the methods described in claims 1-6.