CN-122010106-A - Controllable thermal expansion preparation method of graphene oxide layer

CN122010106ACN 122010106 ACN122010106 ACN 122010106ACN-122010106-A

Abstract

The invention discloses a controllable thermal expansion preparation method of a graphene oxide layer, which comprises the following steps of S1, S2, S3, S4, modifying graphene oxide through an aminosilane coupling agent, introducing an amino functional group, regulating and controlling acting force among graphene oxide layers, providing a precursor foundation for the follow-up controllable thermal expansion, effectively solving the problem that the thermal expansion of the traditional precursor is uncontrollable due to unstable acting force among layers, adopting a gradient heating thermal expansion process, controlling heating rate and constant temperature time in three stages, realizing orderly execution of moisture removal, functional group decomposition and deep expansion, avoiding local excessive expansion or insufficient expansion caused by single heating rate, ensuring uniform expansion of the graphene oxide layer and controllable pore structure.

Inventors

ZHANG YONG
LI XIAOMEI
LI XIAOFEI
Yu Naihao
LI XIAONING

Assignees

青岛岩海碳材料有限公司

Dates

Publication Date: 20260512
Application Date: 20260209

Claims (4)

1. The preparation method of the controllable thermal expansion of the graphene oxide layer is characterized by comprising the following steps of: Step S1, preparing a modified graphene oxide precursor Adding natural crystalline flake graphite into concentrated sulfuric acid with the mass fraction of 90-98%, stirring for 30-60min under ice bath condition, controlling the ice bath temperature at 0-5 ℃, adding potassium permanganate in batches, wherein the mass ratio of the potassium permanganate to the natural crystalline flake graphite is 3:1-5:1, the feeding rate is 0.5-1g potassium permanganate/10 min per gram of graphite, keeping the system temperature not higher than 10 ℃ in the feeding process, heating to 30-40 ℃ after the feeding is completed, stirring at constant temperature for 120-180min, slowly adding deionized water, the volume ratio of deionized water to the concentrated sulfuric acid is 3:1-5:1, the feeding rate is 5-10mL/min, heating to 90-95 ℃ after the feeding is completed, reacting at constant temperature for 30-60min, finally adding 30% hydrogen peroxide until bubbles are not generated in the system, filtering, washing with hydrochloric acid solution with the mass fraction of 5-10% for 3-5 times, washing with deionized water until the pH value of filtrate is 6.5-7.5, and freeze-drying to obtain graphene oxide; Adding the graphene oxide into deionized water, performing ultrasonic dispersion for 30-60min, obtaining graphene oxide dispersion liquid with the mass concentration of 0.5-2mg/mL, adding an aminosilane coupling agent into the dispersion liquid, performing stirring reaction for 60-120min at 50-70 ℃, performing centrifugal separation after the reaction is finished, washing the precipitate with deionized water for 3-4 times, and performing vacuum drying to obtain a modified graphene oxide precursor; step S2, preparing a graphene oxide layer prefabricated body Adding the modified graphene oxide precursor obtained in the step S1 into deionized water, performing ultrasonic dispersion for 20-40min, and performing ultrasonic power for 120-180W to obtain modified graphene oxide dispersion liquid with the mass concentration of 0.3-1.5mg/mL, pouring the dispersion liquid onto a filter membrane of a vacuum suction filtration device, performing vacuum suction filtration, wherein the pore diameter of the filter membrane is 0.22-0.45 mu m, and performing vacuum suction filtration until a uniform graphene oxide film is formed on the filter membrane, transferring the graphene oxide film and the filter membrane into a vacuum drying box, drying for 120-180min under the conditions of 60-80 ℃ and the vacuum degree of 0.08-0.1MPa, and peeling the filter membrane after drying is completed to obtain a graphene oxide layer preform with the thickness of 5-20 mu m; Step S3, gradient heating controllable thermal expansion treatment Placing the graphene oxide layer preform obtained in the step S2 into a tubular furnace, firstly introducing inert gas into the tubular furnace, wherein the flow rate of the inert gas is 20-50mL/min, the ventilation time is 30-60min, and removing air in the furnace; then carrying out gradient heating, namely heating from room temperature to 150-200 ℃ at a heating rate of 2-5 ℃ per minute for 30-60min at a constant temperature in a first heating stage; a second heating stage, namely heating from 150-200 ℃ to 400-500 ℃, wherein the heating rate is 5-10 ℃ per minute, and keeping the temperature for 60-90 minutes; A third heating stage, namely heating from 400-500 ℃ to 700-850 ℃, wherein the heating rate is 3-6 ℃ per minute, and the temperature is kept for 40-80 minutes; The inert gas is kept continuously introduced in the thermal expansion process, and the flow rate is kept at 20-50mL/min; Step S4, post-treatment shaping Cooling to room temperature at a rate of 5-8 ℃ per minute after thermal expansion is finished, taking out a sample, putting the sample into a dilute sulfuric acid solution with a mass fraction of 1-3% for soaking for 20-30min, wherein the soaking temperature is 25-35 ℃, then washing with deionized water until the pH value of filtrate is 6.8-7.2, putting into a vacuum drying box, and drying for 60-90min under the conditions of 50-70 ℃ and vacuum degree of 0.08-0.1MPa to obtain the graphene oxide layer with controllable thermal expansion.
2. The method for preparing a graphene oxide layer by controllable thermal expansion according to claim 1, wherein the aminosilane coupling agent in the step S1 is one or two of gamma-aminopropyl triethoxysilane and gamma-aminopropyl trimethoxysilane mixed according to any proportion.
3. The method for preparing a graphene oxide layer by controllable thermal expansion according to claim 1, wherein the inert gas in the step S3 is one or two of nitrogen and argon mixed according to any proportion.
4. The method for preparing a graphene oxide layer by controllable thermal expansion according to claim 1, wherein the filter membrane in the step S2 is one of a polyvinylidene fluoride filter membrane and a mixed cellulose ester filter membrane.

Description

Controllable thermal expansion preparation method of graphene oxide layer Technical Field The invention belongs to the technical field of graphene oxide material preparation, and particularly relates to a controllable thermal expansion preparation method of a graphene oxide layer. Background Graphene oxide is an important derivative of graphene, has rich oxygen-containing functional groups, good dispersibility and excellent physicochemical properties, and has wide application prospects in various fields of energy storage materials, composite materials, adsorption materials and the like. The thermal expansion treatment is one of key means for regulating and controlling the structure and performance of the graphene oxide layer, and the thermal expansion can increase the interlayer distance of the graphene oxide layer to form a porous structure, so that the specific surface area, the adsorption performance and the like of the graphene oxide layer are improved. However, the existing graphene oxide layer thermal expansion preparation method generally has the problem that the thermal expansion process is uncontrollable, and the problems are mainly manifested in difficulty in accurately regulating and controlling the thermal expansion rate and uneven expansion degree, so that the prepared graphene oxide layer has disordered pore structure and poor performance stability. In the traditional method, thermal expansion is carried out by adopting a single heating rate, irreversible agglomeration or structural damage of the graphene oxide layer is easy to occur due to local temperature sudden rise, and meanwhile, an effective precursor modification means is lacked, so that the accurate control of the thermal expansion process can not be realized by regulating and controlling the precursor performance. In addition, the post-treatment process of the sample after thermal expansion in the existing method is simple, the stability of the sample structure is difficult to ensure, and the application of the sample in the high-end field is further limited. Therefore, developing a method capable of realizing accurate control of a thermal expansion process, uniform structure of a prepared graphene oxide layer and stable performance becomes a technical problem to be solved in the field of preparation of the current graphene oxide materials. Based on the method, a controllable thermal expansion preparation method of the graphene oxide layer is designed. Disclosure of Invention Aiming at the situation, in order to overcome the defects of the prior art, the invention provides a controllable thermal expansion preparation method of a graphene oxide layer, which effectively solves the problems presented by the background. In order to achieve the above purpose, the invention provides a controllable thermal expansion preparation method of a graphene oxide layer, which comprises the following steps: Step S1, preparing a modified graphene oxide precursor Adding natural crystalline flake graphite into concentrated sulfuric acid with the mass fraction of 90-98%, stirring for 30-60min under ice bath condition, controlling the ice bath temperature at 0-5 ℃, adding potassium permanganate in batches, wherein the mass ratio of the potassium permanganate to the natural crystalline flake graphite is 3:1-5:1, the feeding rate is 0.5-1g potassium permanganate/10 min per gram of graphite, keeping the system temperature not higher than 10 ℃ in the feeding process, heating to 30-40 ℃ after the feeding is completed, stirring at constant temperature for 120-180min, slowly adding deionized water, the volume ratio of deionized water to the concentrated sulfuric acid is 3:1-5:1, the feeding rate is 5-10mL/min, heating to 90-95 ℃ after the feeding is completed, reacting at constant temperature for 30-60min, finally adding 30% hydrogen peroxide until bubbles are not generated in the system, filtering, washing with hydrochloric acid solution with the mass fraction of 5-10% for 3-5 times, washing with deionized water until the pH value of filtrate is 6.5-7.5, and freeze-drying to obtain graphene oxide; Adding the graphene oxide into deionized water, performing ultrasonic dispersion for 30-60min, obtaining graphene oxide dispersion liquid with the mass concentration of 0.5-2mg/mL, adding an aminosilane coupling agent into the dispersion liquid, performing stirring reaction for 60-120min at 50-70 ℃, performing centrifugal separation after the reaction is finished, washing the precipitate with deionized water for 3-4 times, and performing vacuum drying to obtain a modified graphene oxide precursor; step S2, preparing a graphene oxide layer prefabricated body Adding the modified graphene oxide precursor obtained in the step S1 into deionized water, performing ultrasonic dispersion for 20-40min, and performing ultrasonic power for 120-180W to obtain modified graphene oxide dispersion liquid with the mass concentration of 0.3-1.5mg/mL, pouring the dispersion liquid onto a