阅读说明：本技术 一种直接对石墨烯进行共价键改性的石墨烯分散液制备方法 (Preparation method of graphene dispersion liquid for directly carrying out covalent bond modification on graphene ) 是由 牛刚 李杰慧 任巍 马艳杰 于 2019-11-29 设计创作，主要内容包括：本发明公开了一种直接对石墨烯进行共价键改性的石墨烯分散液制备方法,包括将石墨烯和溶剂混合获得石墨烯浆料；将石墨烯浆料通过两步超声处理得到石墨烯分散液；在石墨烯分散液中加入烷基胺改性物质进行共价键改性,得到改性的石墨烯分散液。本发明的石墨烯二甲苯分散液中的石墨烯纳米片面积大、层数少、缺陷少,工艺过程简单且易重复,可实现量产、工业化,具有广泛的应用前景。(The invention discloses a preparation method of a graphene dispersion liquid for directly carrying out covalent bond modification on graphene, which comprises the steps of mixing graphene with a solvent to obtain graphene slurry; carrying out two-step ultrasonic treatment on the graphene slurry to obtain a graphene dispersion liquid; and adding an alkylamine modified substance into the graphene dispersion liquid for covalent bond modification to obtain the modified graphene dispersion liquid. The graphene nanosheet in the graphene xylene dispersion liquid disclosed by the invention is large in area, few in layer number, few in defects, simple in process, easy to repeat, capable of realizing mass production and industrialization, and wide in application prospect.)

1. A preparation method of a graphene dispersion liquid for directly carrying out covalent bond modification on graphene is characterized by comprising the following steps:

mixing graphene and a solvent to obtain graphene slurry;

carrying out two-step ultrasonic treatment on the graphene slurry to obtain a graphene dispersion liquid;

and adding an alkylamine modified substance into the graphene dispersion liquid for covalent bond modification, and performing ultrasonic treatment to obtain the modified graphene dispersion liquid.

2. The method for preparing the graphene dispersion liquid by directly carrying out covalent bond modification on graphene according to claim 1, wherein the solvent is xylene, and the solid-to-liquid ratio of graphene to xylene is (1-5) mg:1 ml.

3. The method for preparing the graphene dispersion liquid by directly carrying out covalent bond modification on graphene according to claim 1, wherein the two-step ultrasonic treatment specifically comprises:

placing the graphene slurry into an ultrasonic cell crushing instrument, and preparing a roughly dispersed graphene dispersion liquid after ultrasonic treatment;

and putting the roughly dispersed graphene dispersion liquid into an ultrasonic cleaning instrument, and performing ultrasonic treatment to obtain the finely dispersed graphene dispersion liquid.

4. The method for preparing the graphene dispersion liquid by directly carrying out covalent bond modification on graphene according to claim 3, wherein the power of the ultrasonic cell disruptor is 390-650W, and the ultrasonic time is 15-60 minutes.

5. The method for preparing graphene dispersion liquid directly subjected to covalent bond modification according to claim 3, wherein the diameter of the bottom of an ultrasonic bar in the cell disruptor is 6 mm.

6. The method for preparing graphene dispersion liquid by directly performing covalent bond modification on graphene according to claim 3, wherein the working frequency is 2 seconds of rest every 3 seconds of working.

7. The preparation method of the graphene dispersion liquid for directly carrying out covalent bond modification on graphene according to claim 3, wherein the ultrasonic time of the ultrasonic cleaning instrument is 30-90 minutes.

8. The method for preparing a graphene dispersion liquid by directly performing covalent bond modification on graphene according to claim 1, wherein the alkylamine-modified substance is dodecylamine or hexadecylamine, and the mass ratio of the alkylamine-modified substance to graphene is (5-50): 1.

9. The method for preparing the graphene dispersion liquid by directly carrying out covalent bond modification on graphene according to claim 1, wherein the graphene is subjected to ultrasonic treatment for 10-30 minutes under the condition that the ultrasonic power is 50-120W after the alkylamine modified substance is added.

Technical Field

The invention belongs to the technical field of graphene, and particularly relates to a preparation method of a graphene dispersion liquid for directly carrying out covalent bond modification on graphene.

Background

Graphene is a two-dimensional material, and has the advantages of large specific surface area, high electron mobility, good electric conductivity, high strength, good heat conductivity, good barrier property and the like, so that the graphene is widely applied to the fields of mobile equipment, new energy batteries, satellite communication, anticorrosive coatings and the like. However, due to the large specific surface area of graphene and the interaction of van der waals force between layers of graphene, graphene is easy to agglomerate and disperse in a solvent, which limits the wide application of graphene.

In order to stably disperse graphene in a solvent, graphene needs to be modified. At present, the modification modes of graphene mainly comprise non-covalent bond modification and covalent bond modification. The covalent bond modification is realized by the covalent bond action between the oxygen-containing group on the surface of the graphene and the modifier, so that the modification purpose is achieved, and the bonding strength between the modifier and the graphene is high; however, the covalent bond modification generally modifies graphene oxide first, and then reduces the modified graphene to obtain the modified graphene, so that the preparation process is complex, and the graphene oxide may influence the reduction process of the oxygen-containing functional group due to the introduction of a new functional group.

In addition, although there are some methods for preparing an aqueous dispersion of modified graphene for different solvents, the application field of the aqueous dispersion of graphene is limited, and thus, it is necessary to prepare an organic dispersion of graphene. Xylene is an organic solvent widely used in the fields of coatings, resins, dyes, inks and the like, and can be used as a solvent for graphene dispersion. However, since the modification substance is often incompatible with xylene, resulting in poor modification effect and even affecting the original dispersion effect of graphene, it is also important to select a modification substance compatible with a corresponding solvent, and there is a need to develop a method for directly performing covalent bond modification on graphene and obtaining graphene xylene dispersion, which is compatible with xylene.

Disclosure of Invention

Aiming at the problem of poor dispersion effect caused by incompatibility of graphene dispersion liquid in the prior art, the invention provides a preparation method of graphene dispersion liquid for directly carrying out covalent bond modification on graphene, and solves the problem that graphene is easy to agglomerate in a xylene solvent.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a graphene dispersion liquid for directly carrying out covalent bond modification on graphene comprises the following steps:

mixing graphene and a solvent to obtain graphene slurry;

carrying out two-step ultrasonic treatment on the graphene slurry to obtain a graphene dispersion liquid;

and adding an alkylamine modified substance into the graphene dispersion liquid for covalent bond modification, and performing ultrasonic treatment to obtain the modified graphene dispersion liquid.

As a further improvement of the method, the solvent is xylene, and the solid-to-liquid ratio of the graphene to the xylene is (1-5) mg:1 ml.

As a further improvement of the present invention, the two-step ultrasonic treatment specifically comprises:

placing the graphene slurry into an ultrasonic cell crushing instrument, and preparing a roughly dispersed graphene dispersion liquid after ultrasonic treatment;

and putting the roughly dispersed graphene dispersion liquid into an ultrasonic cleaning instrument, and performing ultrasonic treatment to obtain the finely dispersed graphene dispersion liquid.

As a further improvement of the invention, the power of the ultrasonic cell crusher is 390-650W, and the ultrasonic time is 15-60 minutes; the diameter of the bottom of the ultrasonic rod in the cell crushing instrument is 6 mm; the operating frequency was 2 seconds of rest per 3 seconds of operation.

As a further improvement of the invention, the ultrasonic time of the ultrasonic cleaning instrument is 30-90 minutes.

As a further improvement of the invention, the alkylamine modified substance can be dodecylamine or hexadecylamine, and the mass ratio of the alkylamine modified substance to the graphene is (5-50): 1.

As a further improvement of the invention, after the alkylamine modified substance is added, the ultrasonic operation is ultrasonic treatment for 10-30 minutes by an ultrasonic cleaning instrument under the condition that the ultrasonic power is 50-120W.

Compared with the prior art, the invention has the following beneficial effects:

the invention relates to a preparation method of a graphene dispersion liquid for directly carrying out covalent bond modification on graphene, which comprises the steps of mixing graphene and dimethylbenzene to obtain graphene slurry, then preparing the graphene dispersion liquid through two-step ultrasound, wherein the graphene in the graphene dispersion liquid subjected to the two-step ultrasound can be uniformly dispersed in an external force in a short time, at the moment, a modifying substance is added into the graphene dispersion liquid for covalent modification, so that the modifying substance can more fully and uniformly modify the graphene, and finally, the modified graphene dispersion liquid has the advantages of few defects, thin layer number, good quality, no need of hydrothermal reduction and other steps, is simple to operate and can be applied to an anticorrosive coating.

Furthermore, the alkylamine modified substance and the solvent xylene have good intermiscibility, so that the stability of the modified graphene dispersion liquid is improved.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

Fig. 1 is an atomic force microscope image of graphene in a graphene dispersion prepared according to an embodiment of the present invention;

fig. 2 is a raman laser spectrum of graphene in the graphene dispersion liquid prepared in the embodiment of the present invention;

fig. 3 is a graphene X-ray photoelectron spectrum of the graphene dispersion prepared in the embodiment of the present invention;

fig. 4 is a fourier transform infrared spectrum of graphene in the graphene dispersion liquid prepared in the embodiment of the present invention;

fig. 5 is a graph comparing a modified graphene dispersion prepared according to an example of the present invention with an unmodified graphene dispersion.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a preparation method of a graphene dispersion liquid for directly carrying out covalent bond modification on graphene, and the xylene dispersion liquid of graphene is obtained by ultrasonic. Covalent modification is carried out on graphene by adopting dodecylamine. And further performing ultrasonic dispersion to obtain a modified graphene dispersion liquid. The obtained modified graphene dispersion liquid has the advantages of few defects, thin layer number, good quality, no need of steps such as hydrothermal reduction and the like, simple operation and can be applied to anticorrosive coatings.

The invention relates to a preparation method of a graphene dispersion liquid for directly carrying out covalent bond modification on graphene, which comprises the following steps:

s1, weighing graphene and xylene according to a proportion to a reagent bottle;

graphene: the concentration of the graphene slurry is 1-5 mg/ml, and the concentration of the graphene slurry is 1-5 mg/ml.

S2, placing the reagent bottle into an ultrasonic cell crushing instrument, and setting the mode as

(the diameter of the bottom of the ultrasonic rod is 6mm), the power is 390-650W, the time is 15-60 minutes, and the roughly dispersed graphene dispersion liquid is prepared by taking a rest for two seconds every three seconds.

S3, subjecting the graphene dispersion liquid prepared in the step S2 to ultrasonic cleaning in an ultrasonic cleaning instrument for 30-90 minutes to obtain finely dispersed graphene dispersion liquid.

S4, uniformly distributing the graphene dispersion liquid prepared in the step S3, respectively adding a modified substance into the graphene dispersion liquid, and dispersing the modified graphene dispersion liquid for 10-30 minutes through 50-120W ultrasonic treatment. The mass ratio of the modified substance to the graphene is 20:1, 30:1, 40:1 and 50:1 respectively.

A preferred modifying material is Dodecylamine (DA) having a molecular weight of 185.35. The modifying material may also be other alkylamine modifying materials.