A polysiloxane-modified single-layer graphene and a method for preparing the same
By using the silane-hydrogen bond condensation reaction between hydrogen-containing polysiloxane and monolayer graphene oxide, the problem of uniform dispersion of monolayer graphene oxide in nonpolar solvents was solved, achieving efficient modification and improved hydrophobicity, thus expanding its application prospects.
Patent Information
- Application Number
- CN202310677295.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-08
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2043-06-08
AI Technical Summary
In existing technologies, monolayer graphene oxide is difficult to disperse uniformly in nonpolar organic solvents, resulting in low modification efficiency, poor chemical selectivity, and difficulty in controlling the modified structure, thus limiting its applications.
Hydrogen-containing polysiloxanes are reacted with monolayer graphene oxide to modify it through a silicon-hydrogen bond condensation reaction. The hydrophobicity is improved by using macromolecular polysiloxanes, and the modification efficiency and selectivity are ensured by controlling the reaction conditions.
The modification reaction was highly efficient, completed in a short time, with few byproducts. The modified monolayer graphene oxide also exhibits excellent hydrophobicity and controllable molecular weight, expanding its application range.
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Figure CN116750759B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of modified graphene oxide, in particular to a polysiloxane modified single-layer graphene oxide and a preparation method thereof. BACKGROUND
[0002] Single-layer graphene oxide is an oxidation product of graphene, which has anisotropy, high specific surface area, good water solubility and easy chemical modification, thus attracting extensive attention. Due to the presence of polar groups such as carboxyl, hydroxyl and epoxy on the surface of single-layer graphene oxide, the single-layer graphene oxide has good water solubility and processability. However, it is difficult for the single-layer graphene oxide to be dissolved in non-polar organic solvents or uniformly dispersed in non-polar polymers, thus limiting the application of the single-layer graphene oxide. To solve this problem, a common method is to chemically modify the single-layer graphene oxide to graft non-polar chemical structures on the surface of the single-layer graphene oxide, thereby increasing the hydrophobicity of the single-layer graphene oxide. An organosilicon reagent is a common chemical modifier.
[0003] At present, most of the organosilicon modified graphene oxides use silane or silane coupling agents as the modification reagent, such as chlorosilane, alkoxy vinyl silane and amino silane, and the modification is completed by condensation reaction between the silicon hydroxyl obtained by hydrolysis of the silane and the hydroxyl in the graphene oxide. However, the silicon hydroxyl is prone to self-condensation, and the reactivity of the silicon hydroxyl with the hydroxyl in the graphene oxide is low, thus resulting in low modification efficiency, poor chemical selectivity and difficult control of the modified structure. Therefore, it is of great significance to provide a modified single-layer graphene oxide with high modification efficiency, good chemical selectivity, clear modification structure and excellent hydrophobicity. SUMMARY
[0004] The present application aims to overcome the problems in the prior art and provide a polysiloxane modified single-layer graphene oxide and a preparation method thereof.
[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:
[0006] The present application provides a preparation method of a polysiloxane modified single-layer graphene oxide, which comprises the following steps:
[0007] The single-layer graphene oxide, the hydrogen-containing polysiloxane, the organic solvent and the catalyst are mixed and reacted to obtain the polysiloxane modified single-layer graphene oxide.
[0008] Preferably, the hydrogen-containing polysiloxane is a single-end hydrogen-containing polydimethylsiloxane, and the relative molecular mass of the hydrogen-containing polysiloxane is 500-5000.
[0009] As preferred, the mass ratio of the single-layer graphene oxide and the hydrogen-containing polysiloxane is 1:0.1-10.
[0010] As preferred, the organic solvent comprises N,N-dimethylacrylamide and toluene.
[0011] As preferred, the volume ratio of the N,N-dimethylacrylamide and toluene is 1:0.5-3.
[0012] As preferred, the mass-volume ratio of the single-layer graphene oxide and the organic solvent is 1-50 g:1 L.
[0013] As preferred, the catalyst is tris-pentafluorophenyl boron.
[0014] As preferred, the mass fraction of the catalyst in the mixed solution is 0.1-3%.
[0015] As preferred, the temperature of the reaction is 20-30°C, and the time is 1-2 h.
[0016] The application further provides the polysiloxane-modified single-layer graphene oxide obtained by the preparation method.
[0017] The application has the following advantages:
[0018] (1) The application provides a preparation method of polysiloxane-modified single-layer graphene oxide, comprising the following steps: mixing single-layer graphene oxide, hydrogen-containing polysiloxane, an organic solvent and a catalyst, and reacting to obtain polysiloxane-modified single-layer graphene oxide. The application utilizes the condensation reaction between the Si-H bond in the hydrogen-containing polysiloxane and the hydroxyl group in the single-layer graphene oxide to modify the single-layer graphene oxide, and has the advantages of high reaction activity, short reaction time and no other by-products except hydrogen.
[0019] (2) The polysiloxane-modified single-layer graphene oxide prepared by the application has macromolecular polysiloxane grafted on the surface of the single-layer graphene oxide, and the single-layer graphene oxide modified by the macromolecular polysiloxane has better hydrophobicity than that modified by a small-molecule silane modifier.
[0020] (3) The application can accurately control the molecular weight of the polysiloxane grafted on the surface of the single-layer graphene oxide, and has a wide application prospect. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 The figure is the contact angle diagram of the polysiloxane-modified single-layer graphene oxide in Example 1.
[0022] Figure 2 The figure is the contact angle diagram of the silane-modified single-layer graphene oxide in Example 1. DETAILED DESCRIPTION
[0023] The application provides a preparation method of polysiloxane modified single-layer graphene oxide, comprising the following steps:
[0024] The single-layer graphene oxide, hydrogen-containing polysiloxane, organic solvent and catalyst are mixed to obtain the polysiloxane modified single-layer graphene oxide.
[0025] In the application, the hydrogen-containing polysiloxane is preferably single-end hydrogen-containing polydimethylsiloxane, the polydimethylsiloxane is preferably terminated by Si-H bond at one end and terminated by trimethylsilyl group at the other end, and the relative molecular mass of the hydrogen-containing polysiloxane is preferably 500-5000, further preferably 1000-4500, and more preferably 2000-3500.
[0026] In the application, the mass ratio of the single-layer graphene oxide and the hydrogen-containing polysiloxane is preferably 1:0.1-10, further preferably 1:1-9, and more preferably 1:2-8.
[0027] In the application, the organic solvent preferably comprises N,N-dimethylacrylamide and toluene.
[0028] In the application, the volume ratio of the N,N-dimethylacrylamide and toluene is preferably 1:0.5-3, further preferably 1:1-2.5, and more preferably 1:1.5-2.
[0029] In the application, the mass-volume ratio of the single-layer graphene oxide and the organic solvent is preferably 1-50 g:1 L, further preferably 5-40 g:1 L, and more preferably 10-30 g:1 L.
[0030] In the application, the catalyst is preferably tri(pentafluorophenyl)boron.
[0031] In the application, the mass fraction of the catalyst in the mixed solution is preferably 0.1-3%, further preferably 0.5-2.5%, and more preferably 1-2%.
[0032] In the application, the mixing is preferably first mixing the single-layer graphene oxide with the organic solvent, then adding the hydrogen-containing polysiloxane to perform second mixing, and finally adding the catalyst to perform third mixing.
[0033] In the application, the ultrasonic frequency of the first mixing is preferably 40-100 kHz, further preferably 50-90 kHz, and more preferably 60-80 kHz; the time of the first mixing is preferably 5-20 min, further preferably 10-15 min, and more preferably 12-13 min; and the conditions of the second mixing and the third mixing are consistent with those of the first mixing.
[0034] In the present application, the reaction is carried out under stirring; the stirring speed is preferably 300-3000 r / min, further preferably 500-2700 r / min, and more preferably 1000-2000 r / min; the reaction temperature is preferably 20-30℃, further preferably 22-28℃, and more preferably 23-27℃; and the time is preferably 1-2 h, further preferably 1.2-1.8 h, and more preferably 1.3-1.7 h.
[0035] In the present application, after the reaction is completed, the obtained system is subjected to vacuum distillation, and then centrifugation, to obtain the polysiloxane-modified single-layer graphene oxide.
[0036] In the present application, the purpose of vacuum distillation is to remove most of the organic solvent in the system; the temperature of vacuum distillation is preferably 75-100℃, further preferably 80-95℃, and more preferably 85-90℃; the time of vacuum distillation is preferably 0.5-1.5 h, further preferably 0.7-1.3 h, and more preferably 0.9-1.1 h; the speed of centrifugation is preferably 5000-7000 r / min, further preferably 5500-6500 r / min, and more preferably 5700-6300 r / min; and the time of centrifugation is preferably 5-20 min, further preferably 7-17 min, and more preferably 9-16 min. The present application also provides polysiloxane-modified single-layer graphene oxide prepared by the preparation method.
[0037] The technical solutions provided by the present application will be described in detail below in conjunction with the examples, but they should not be understood as limiting the scope of protection of the present application.
[0038] Example 1
[0039] 10 mg of single-layer graphene oxide was ultrasonically mixed with 5 mL of N,N-dimethylacrylamide and 5 mL of toluene at 50 kHz for 5 min, then 100 mg of monohydrogen-terminated polydimethylsiloxane with a relative molecular mass of 1000 was added and ultrasonically mixed at 50 kHz for 5 min, and finally 3,5-difluorophenyl boron was added and ultrasonically mixed at 50 kHz for 5 min (the mass fraction of 3,5-difluorophenyl boron in the mixed solution was 0.5%), and then the mixture was reacted at a temperature of 25℃ and a speed of 2000 r / min for 1 h. After the reaction was completed, the mixture was subjected to vacuum distillation at 80℃ for 1.1 h, and then centrifuged at 6500 r / min for 9 min, to obtain polysiloxane-modified single-layer graphene oxide.
[0040] In this comparative example, other conditions were kept constant. The single-end hydrogen-containing polydimethylsiloxane was replaced with methyltrimethoxysilane, the catalyst was replaced with tris(pentafluorophenylborone)acetic acid, the amount of acetic acid added was modified to 0.5 mL, the reaction temperature was modified to 70 °C, and the reaction time was modified to 5 h, thus obtaining silane-modified monolayer graphene oxide.
[0041] Polysiloxane-modified monolayer graphene oxide and silane-modified monolayer graphene oxide were sequentially dried and pressed into tablets, and their contact angles were measured to obtain a contact angle diagram of the polysiloxane-modified monolayer graphene oxide, as shown below. Figure 1 The contact angle diagram of silane-modified monolayer graphene oxide is shown below. Figure 2 As shown. From Figure 1 and Figure 2 As can be seen, the contact angle of polysiloxane-modified monolayer graphene oxide is 120.3°, while that of silane-modified monolayer graphene oxide is 87°. The hydrophobicity of polysiloxane-modified monolayer graphene oxide is significantly better than that of silane-modified monolayer graphene oxide.
[0042] Example 2
[0043] 50 mg of monolayer graphene oxide was sonicated with 6.5 mL of N,N-dimethylacrylamide and 3.5 mL of toluene at 40 kHz for 17 min. Then, 50 mg of single-ended hydrogen-containing polydimethylsiloxane with a relative molecular mass of 500 was added, and the mixture was sonicated at 40 kHz for 17 min. Finally, tris(pentafluorophenylboron) was added, and the mixture was sonicated at 40 kHz for 17 min (the mass fraction of tris(pentafluorophenylboron) in the mixed solution was 0.9%). The mixture was then reacted at 27 °C and 1000 r / min for 2 h. After the reaction was completed, the mixture was distilled under reduced pressure at 90 °C for 0.7 h, and then centrifuged at 5700 r / min for 16 min to obtain polysiloxane-modified monolayer graphene oxide.
[0044] Example 3
[0045] 1 g of monolayer graphene oxide was sonicated with 176 mL of N,N-dimethylacrylamide and 124 mL of toluene at 60 kHz for 15 min. Then, 1 g of single-ended hydrogen-containing polydimethylsiloxane with a relative molecular mass of 5000 was added, and the mixture was sonicated at 60 kHz for 15 min. Finally, tris(pentafluorophenyl)boron was added, and the mixture was sonicated at 60 kHz for 15 min (the mass fraction of tris(pentafluorophenyl)boron in the mixed solution was 1.5%). The mixture was then reacted at 23 °C and 2700 r / min for 1.5 h. After the reaction was completed, the mixture was distilled under reduced pressure at 85 °C for 1.3 h, and then centrifuged at 5500 r / min for 20 min to obtain polysiloxane-modified monolayer graphene oxide.
[0046] From the above examples, the present application utilizes the condensation reaction between the Si-H bond in the hydrogen-containing polysiloxane and the hydroxyl group in the single-layer graphene oxide to modify the single-layer graphene oxide, and has the advantages of high reactivity, short reaction time, and no other by-products except hydrogen. The polysiloxane modified single-layer graphene oxide prepared by the present application has macromolecular polysiloxane grafted on the surface of the single-layer graphene oxide, and the single-layer graphene oxide modified by the macromolecular polysiloxane has better hydrophobicity than that modified by a small molecule silane modifier. In addition, the present application can accurately control the molecular weight of the polysiloxane grafted on the surface of the single-layer graphene oxide, and has a wide application prospect.
[0047] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.
Claims
1. A method for producing a polysiloxane-modified single-layer graphene oxide, characterized by, The preparation method comprises the following steps: mixing single-layer graphene oxide, hydrogen-containing polysiloxane, organic solvent and catalyst to react to obtain the polysiloxane modified single-layer graphene oxide; the catalyst is trifluorophenyl boron, and the mass fraction of the catalyst in the mixed solution is 0.1-3%.
2. The production method according to claim 1, wherein the hydrogen-containing polysiloxane is single-end hydrogen-containing polydimethylsiloxane, and the relative molecular mass of the hydrogen-containing polysiloxane is 500-5000.
3. The production method according to claim 2, wherein the mass ratio of the single-layer graphene oxide and the hydrogen-containing polysiloxane is 1:0.1-10.
4. The production method according to claim 3, wherein the organic solvent comprises N,N-dimethylacrylamide and toluene.
5. The production method according to claim 4, wherein the volume ratio of the N,N-dimethylacrylamide and toluene is 1:0.5-3.
6. The production method according to claim 5, wherein the mass-volume ratio of the single-layer graphene oxide and the organic solvent is 1-50g:1L.
7. The production method according to claim 6, wherein the reaction temperature is 20-30℃, and the reaction time is 1-2h.
8. The polysiloxane modified single-layer graphene oxide obtained by the preparation method in any one of claims 1-7.
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