CN-122010102-A - Graphene composite material and preparation method thereof

Abstract

The invention particularly relates to a graphene composite material and a preparation method thereof, comprising the following steps of ultrasonically dispersing graphene oxide in a buffer solution, sequentially adding ascorbic acid and dopamine, ultrasonically dispersing, and then stirring for reaction; filtering and washing the reacted solution, dispersing the obtained filter cake in deionized water to obtain a dispersion liquid, adding an iron salt solution into the dispersion liquid for ultrasonic dispersion, heating and stirring for reaction, adding an alkaline reagent into the dispersion liquid for regulating pH value, continuously stirring for reaction, filtering and washing the reaction liquid for drying to obtain the composite wave-absorbing material of the polydopamine reduced graphene oxide/Fe 3 O 4 . According to the invention, graphene oxide can be reduced properly through a green, environment-friendly, nontoxic and harmless process to obtain the reduced graphene oxide with the conductivity being adaptive so as to prepare the wave-absorbing material, the preparation method is simple, and the prepared polydopamine/reduced graphene oxide/Fe 3 O 4 composite wave-absorbing material has good wave-absorbing capacity and certain advancement.

Inventors

• MA ZHIYUAN
• Zhang sa
• YE CHANGHUAI
• LIAO YAOZU

Assignees

• 东华大学

Dates

Publication Date

20260512

Application Date

20251030

Claims (10)

1. 1. The preparation method of the graphene composite material is characterized by comprising the following steps of: (1) Ultrasonically dispersing graphene oxide in a buffer solution, sequentially adding ascorbic acid and dopamine, ultrasonically dispersing, and then stirring for reaction; (2) Filtering and washing the solution obtained after the reaction in the step (1), dispersing the obtained filter cake in deionized water to obtain a dispersion liquid, adding an iron salt solution into the dispersion liquid, carrying out ultrasonic dispersion, heating and stirring for reaction, then adding an alkaline reagent into the dispersion liquid to adjust the pH value, and continuing stirring for reaction; (3) And (3) filtering, washing and drying the reaction liquid in the step (2) to obtain the graphene composite material, namely the polydopamine reduced graphene oxide/Fe 3 O 4 composite wave-absorbing material.
2. 2. The preparation method of the graphene composite material according to claim 1, wherein the graphene oxide in the step (1) is a few-layer graphene oxide prepared by a Hummers method, the buffer solution is a Tris-HCl solution, and the pH value of the solution is 8.0-8.5.
3. 3. The preparation method of the graphene composite material according to claim 1 or 2 is characterized in that in the step (1), the mass ratio of graphene oxide to dopamine to ascorbic acid is 1:1:0.5-2, the concentration of graphene oxide is 1-3mg/ml respectively, and the stirring reaction condition is that stirring is carried out at room temperature for 12-24 h and the stirring speed is 300-800 rpm.
4. 4. The method of claim 1, wherein the iron salt in the step (2) is ferrous ammonium sulfate and ferric ammonium sulfate, and the molar ratio of ferrous ammonium sulfate to ferric ammonium sulfate is 1:3-1:1.5.
5. 5. The preparation method of the graphene composite material according to claim 1, wherein the concentration of ferrous ammonium sulfate in the step (2) is 20-80 mmol/L, the concentration of ferric ammonium sulfate is 40-160 mmol/L, and the mass-volume ratio of graphene oxide to the dispersion liquid after the ferric salt is added in the step (1) is 1-3 mg/1 ml.
6. 6. The method for preparing the graphene composite material according to claim 1, wherein the ultrasonic dispersion time in the step (2) is 10-30min, the condition of heating and stirring reaction after adding ferric salt is 50-80 ℃ and the stirring speed is 500-600 rpm.
7. 7. The preparation method of the graphene composite material according to claim 1, wherein the alkaline reagent added in the step (2) is sodium hydroxide or ammonia water, the pH is adjusted to 9-11, and the stirring reaction is continued for 20-60min.
8. 8. The method for preparing a graphene composite material according to claim 1, wherein the drying temperature in the step (3) is 40-80 ℃ and the drying time is 10-16h.
9. 9. A graphene composite material prepared by the method of any one of claims 1-8.
10. 10. The use of the graphene composite material of claim 9 in a wave-absorbing fiber or fabric.

Description

Graphene composite material and preparation method thereof Technical Field The invention relates to the technical field of wave-absorbing materials, in particular to a graphene composite material and a preparation method thereof. Background With rapid development of information technology and increasing convenience of information propagation channels, risks of electromagnetic interference and information leakage are also increasingly highlighted, and electromagnetic pollution problems become challenges to be solved urgently. The unique pore structure and the two-dimensional morphology of single-atom thickness of the graphene enable the graphene to have light weight, large surface area, excellent performance and wide application prospect. In addition, a plurality of suspension bonds in the graphene can effectively resist the influence of an electric field, and the intensity of electromagnetic waves is greatly reduced due to the polarization relaxation of outer-layer electromagnetic waves, so that the electromagnetic waves are effectively absorbed and attenuated, and the characteristics make the graphene an electromagnetic wave absorbing material with great development prospect. Has potential to be a good electromagnetic wave absorbing material. However, due to the defects of poor impedance matching, poor dispersibility in a matrix, few wave absorption loss mechanisms and the like of graphene, the single energy loss mechanism of pure graphene is difficult to meet the impedance matching requirement, and the application of the pure graphene in the field of electromagnetic wave absorption is severely limited, so that the main research focus at present is on graphene derivatives such as Graphene Oxide (GO) and Reduced Graphene Oxide (RGO). GO is usually synthesized by oxidation of expanded graphite and contains a large number of oxygen-containing groups, such as hydroxyl (-OH), carboxyl (-COOH), and epoxy (-O-) functional groups. RGO can be obtained by carrying out reduction treatment of removing oxygen groups on the prepared graphene oxide based on the prepared graphene oxide, has a structure similar to that of graphene, has certain conductivity, and has hydrophilic surface and easy dispersion in solution due to oxygen-containing functional groups on the surface. Patent CN 103342982A discloses a hollow spherical ferroferric oxide/graphene composite wave-absorbing material and a preparation method thereof, wherein the material is prepared by taking graphene as a matrix, loading hollow spherical ferroferric oxide, uniformly mixing in liquid state and carrying out in-situ nucleation growth. In the patent, ferric salt is adsorbed on the surface of graphene oxide, and ferric salt and graphene oxide are reduced into a ferroferric oxide/graphene composite material through urea serving as a reducing agent and hydrazine hydrate respectively, wherein the hydrazine serving as the reducing agent is a highly toxic, volatile and suspected carcinogenic substance, the ferroferric oxide is not environment-friendly, and the ferroferric oxide is physically adsorbed on the surface of a graphene material, so that the risk of falling exists, and the service life of the material is influenced. Patent CN 109348696A relates to an iron-doped tin dioxide/reduced graphene oxide (Fe-SnO 2/RGO) nanocomposite wave-absorbing material and a preparation method thereof. The Fe-SnO 2/RGO binary nanocomposite is prepared by taking Graphene Oxide (GO), tin tetrachloride pentahydrate and ferric nitrate nonahydrate as precursors through one-step hydrothermal reaction. The invention has high hydrothermal reaction temperature, long time and high energy consumption. The patent CN110550626A relates to a method for controllable reduction in modified graphene oxide, which takes chitosan as a matrix, forms a composite material with the graphene oxide, and prepares the graphene by adopting the modes of soaking reduction and hot-pressing reduction of the graphene oxide in a vitamin C matrix, so that the problem that the graphene is easy to agglomerate is solved, but the high hot-pressing temperature can cause severe decomposition of the chitosan, and the performance of the composite material is obviously reduced. Patent CN104399090a relates to a polydopamine modified reduced graphene oxide and a preparation method thereof, the polydopamine modified reduced graphene oxide comprises reduced graphene oxide and polydopamine, the polydopamine is attached to the surface of the reduced graphene oxide in a physical adsorption manner, and the photo-thermal property and photo-acoustic imaging property of the modified material are mainly utilized to be used as a medicament for cancer treatment or in the photo-acoustic imaging field. Disclosure of Invention Aiming at the problems of the graphene oxide materials, the invention provides a graphene composite material and a preparation method thereof. According to the invention, graphene oxide can be reduced through a green,