Graphene oxide-based filler as well as preparation process and application thereof

Abstract

The invention relates to the field of coating fillers, in particular to a graphene oxide-based filler as well as a preparation process and application thereof. The graphene oxide-based filler is prepared from a main material graphene oxide and an auxiliary material, the graphene oxide composite material comprises the following components in parts by mass: 100 parts of graphene oxide as a main material, and 2-13 parts of a silane coupling agent, 5-12 parts of sodium peroxide, 3-12 parts of dopamine hydrochloride and 5000-30000 parts of deionized water as auxiliary materials. The preparation method of the graphene oxide-based filler comprises the following steps: (1) preparing slurry; (2) filtering the slurry; and (3) canning the slurry. The filler has the characteristics of improving the anti-corrosion effect of the anti-corrosion coating and prolonging the service life of the anti-corrosion coating, and is suitable for various coating systems such as water-based coatings, solvent-based coatings, solventless coatings and powder coatings.

Description

Technical field:

[0001] The present invention relates to the field of coating fillers, and in particular to a graphene oxide-based filler and a preparation process and application thereof. Background technology:

[0002] Since its discovery in 2004, graphene has garnered widespread attention from scientists worldwide. Countries around the world, especially developed countries, have identified graphene as a technology crucial to their future core competitiveness. Since 2010, countries and regions such as China, the United States, the United Kingdom, Japan, and the European Union have invested heavily in graphene-related scientific and technological projects and formulated five- to ten-year development plans. Graphene science and technology has become a national development strategy. Graphene exhibits unique functions and applications in electronics, optics, magnetism, biology, sensors, energy storage, and catalysis. Its remarkable physical and chemical properties have also attracted widespread attention from major coatings companies, universities, and research institutes worldwide. International coatings researchers have conducted fruitful exploration and innovation in the industrial preparation of graphene and its application in coatings, achieving remarkable results.

[0003] Researchers in the US and Europe, through early exploration, discovered that graphene, a novel carbon nanomaterial with a single-layer flaky structure, could be used as a filler in anti-corrosion coatings, similar to flaky mica powder, aluminum powder, and glass flakes. Due to its extremely high specific surface area, high surface energy, and strong surface adsorption, graphene forms a network structure during drying, enhancing adhesion between the coating and the substrate, while also further reducing coating thickness and improving wear resistance. Therefore, graphene holds broad application prospects in the field of anti-corrosion coatings. However, graphene's inherent chemical stability—being neither hydrophilic nor oleophilic—and its susceptibility to reaggregation and stacking have limited further research and application. The large-scale synthesis of graphene oxide (GO) sparked a wave of research in the field of anti-corrosion coatings. Graphene oxide (GO) is a key graphene derivative produced during the oxidation-reduction process for graphene materials. Its traditional preparation methods are the three major chemical oxidation methods: the Brodie method, the Staudenmaier method, and the Hummers method. In order to shorten the reaction cycle of preparing graphene oxide and improve the preparation efficiency, three improvements of chemical oxidation methods and reaction-controllable electrochemical oxidation methods have emerged one after another.

[0004] Unlike graphene, graphene oxide contains a large number of oxygen-containing functional groups in its structure. After certain chemical surface modifications, it can be added as a filler to anti-corrosion coatings. Chang KC et al. prepared a super-hydrophobic graphene / epoxy resin coating that cures at room temperature. First, graphene was added to the epoxy coating and coated on the surface of the steel. Then a super-hydrophobic template was pressed on the surface of the coating. After curing at room temperature, the template was removed to obtain a super-hydrophobic coating. TEM observations showed that the dispersion of graphene in the coating was good and no agglomerates were formed, indicating that a small amount of oxygen-containing groups on the graphene obtained by thermal reduction can effectively improve its dispersibility. Molecular gas barrier tests showed that the transmittance of the coating with 1wt% graphene added was reduced by 60%, indicating that the lamellar graphene increased the tortuosity of the molecular diffusion path and played a good physical barrier role. The polarization curve test results showed that compared with pure epoxy coatings, the protective ability of the coating with added graphene was significantly enhanced, and the corrosion current density was reduced by about 10 times. Chang KC et al. also prepared a synergistic superhydrophobic graphene / polymethyl methacrylate coating. The results also showed that the self-corrosion potential of the coating with the addition of graphene was significantly positively shifted, and the protective ability of the coating was significantly improved.

[0005] Krishnamoorthy et al. added graphene oxide to alkyd resin to prepare a novel graphene oxide nanocoating. This composite coating was subjected to acidic solution immersion tests, electrochemical tests, and antibacterial tests. The results showed that the graphene oxide nanocoating exhibited excellent acid corrosion resistance and significantly inhibited the growth of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Chang Kungchin et al. prepared a graphene / polyimide coating via thermal imidization and investigated its corrosion resistance and gas permeability. The results showed that the corrosion protection efficiency of the polyimide composite coating with 1 wt% graphene increased from 81.98% to 98.79%, while oxygen permeability decreased by 29%. Mohammadi et al. added graphene nanosheets to epoxy resin to prepare an anticorrosive coating and investigated its electrochemical behavior and corrosion resistance. The results showed that the coating with 0.5 wt% graphite nanosheets exhibited the best corrosion resistance, enhanced the coating's physical shielding properties, and improved its adhesion.

[0006] In summary, graphene can be applied to a variety of coating systems such as epoxy resin. When added in a small amount, it can significantly improve the physical barrier ability of the coating to external corrosive media and improve the corrosion resistance of the coating.

[0007] Influenced by the global surge in graphene research, domestic researchers have also conducted a series of studies on the preparation of graphene oxide and graphene coatings. For example, Fu Ling et al. divided the Hummers method for preparing graphene oxide into three stages: low-temperature, medium-temperature, and high-temperature reactions. They pointed out that the graphite, potassium permanganate dosage, concentrated sulfuric acid volume, low-temperature reaction time, and the method of water addition during the high-temperature reaction are the main process factors affecting the structure and properties of the final product, while the amount of sodium nitrate has little effect on the degree of product oxidation. Liu Qiongxin et al. added graphene to a zinc-rich epoxy anti-corrosion coating. By optimizing the selection of various components, they found that when the graphene content was 2wt% and the zinc powder content was 35wt%, the coating could withstand a salt spray test of up to 1000 hours. This method significantly reduced the zinc powder content and film thickness while maintaining the coating's corrosion resistance. Graphene's lamellar structure, excellent conductivity, and exceptional chemical stability improve the utilization rate of zinc powder, overcoming the drawback of zinc-rich coatings that rely solely on sacrificing zinc powder as a protective measure. This also reduces the generation of zinc oxide mist during the welding process, thereby minimizing environmental pollution. Sun Mingjuan et al. added aniline-modified graphene to acrylated zinc resin to prepare a graphene anticorrosion and antifouling coating. Antifouling performance tests showed that the graphene antifouling coating showed no plankton attachment after 13 months of dynamic simulation testing, while conventional antifouling coatings showed significant biofouling after just nine months. Anticorrosion performance tests also revealed that after 1000 hours of neutral salt spray resistance, the coating surface showed no corrosion, with corrosion occurring only in scratches. Conventional antifouling coatings exhibited varying degrees of corrosion across the entire surface.

[0008] Graphene is a carbon material with a much higher corrosion potential than metal materials. If graphene with a high corrosion potential overlaps with metal materials and forms a conductive path, it will cause accelerated corrosion of the metal materials. Therefore, how to reduce the conductive path between graphene and metal materials has become one of the difficulties of anti-corrosion coatings with graphene as filler. Summary of the invention:

[0009] The purpose of the present invention is to provide a graphene oxide-based filler and its preparation process and application, and the coating has the characteristics of improving the anti-corrosion effect and service life of the anti-corrosion coating.

[0010] The technical solution of the present invention is:

[0011] A graphene oxide-based filler consists of a main material, graphene oxide, and auxiliary materials. Calculated by weight, the main material comprises 100 parts of graphene oxide, and the auxiliary materials include 2 to 13 parts of a silane coupling agent, 5 to 12 parts of sodium peroxide, 3 to 12 parts of dopamine hydrochloride, and 5,000 to 30,000 parts of deionized water.

[0012] The graphene oxide-based filler is graphene oxide, the silane coupling agent is chemically pure, the purity of sodium peroxide is ≥95wt%, the purity of dopamine hydrochloride is ≥97wt%, and the conductivity of deionized water is ≤0.5mS / cm.

[0013] The preparation process of the graphene oxide-based filler comprises the following steps: (1) slurry preparation; (2) slurry filtration; and (3) slurry canning.

[0014] The preparation process of the graphene oxide-based filler, step (1) slurry preparation process is specifically as follows: deionized water is added to a clean reactor with stirring and heating functions, graphene oxide is added while stirring, after the graphene oxide is evenly dispersed, it is treated with an ultrasonic vibration rod for 0.3 to 1.2 hours, then sodium peroxide is added and stirred for 20 to 40 minutes, then dopamine hydrochloride and silane coupling agent are added and stirred for 20 to 40 minutes, heated to 50 to 120 ° C and stirred for 1 to 4 hours, and cooled to room temperature to obtain a slurry.

[0015] In the preparation process of the graphene oxide-based filler, the slurry filtration process in step (2) is specifically as follows: the slurry is filtered through a 120-200 mesh screen to remove substances that cannot be filtered, and the filtered slurry is collected to obtain filtered slurry.

[0016] The preparation process of the graphene oxide-based filler, step (3) the slurry canning process is specifically as follows: the filtered slurry is injected into a clean and water-free storage tank for sealed storage, and the storage tank is made of stainless steel, tinplate or plastic.

[0017] The graphene oxide-based filler is used as a filler in water-based paints, solvent-based paints, solvent-free paints or powder paints.

[0018] The graphene oxide-based filler is used in a proportion of 0.3 to 3 wt % in the coating.

[0019] The design idea of ​​the present invention is:

[0020] The present invention uses a dispersion of graphene oxide in deionized water as a carrier, ensuring thorough mixing between the main ingredient, graphene oxide, and auxiliary materials, such as a silane coupling agent, sodium peroxide, dopamine hydrochloride, and deionized water, thereby fully leveraging the synergistic effects of the main and auxiliary materials. For example, oxidizing intermediates, such as hydrogen peroxide, generated by sodium peroxide in water, can form a physical or chemical bond between the main and auxiliary materials. The silane coupling agent and dopamine hydrochloride establish stable interfacial bonding with the graphene oxide via their alkoxy silicon functional groups and quaternary ammonium salt functional groups, respectively. Furthermore, deionized water is used as an auxiliary agent to provide a uniform and stable dispersion carrier. Based on these characteristics, a graphene oxide-based filler is ultimately obtained.

[0021] The advantages and beneficial effects of the present invention are:

[0022] 1. The filler prepared by the present invention has a simple preparation process, and the raw materials required in the formula can be directly purchased on the market. It is suitable for various coating systems such as water-based coatings, solvent-based coatings, solvent-free coatings, powder coatings, etc.

[0023] 2. The filler prepared by the present invention is easily dispersed in the coating and has no requirement on the order of addition.

[0024] 3. The filler prepared by the present invention can form a stacked structure of graphene sheets in the coating, delaying the penetration of the corrosive medium into the coating, thereby improving the anti-corrosion performance of the water-based coating. Specific implementation method:

[0025] The following examples are further detailed descriptions of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0026] Example 1:

[0027] In this embodiment, a graphene oxide-based filler and a preparation process thereof include the following steps:

[0028] Step (1) slurry preparation process is as follows: add 5000 g of deionized water into a clean reactor with stirring and heating functions, start stirring and add 100 g of graphene oxide, after the graphene oxide is evenly dispersed, treat it with an ultrasonic vibrator for 1.2 hours, then add sodium peroxide and stir for 30 minutes, then add 3 g of dopamine hydrochloride and 2 g of silane coupling agent KH560 and stir for 30 minutes, heat to 50 ° C and stir for 1 hour, and cool to room temperature to obtain a slurry

[0029] The slurry filtration process in step (2) is specifically as follows: the slurry is filtered through a 120-mesh screen to remove substances that cannot be filtered, and the filtered slurry is collected to obtain filtered slurry.

[0030] The specific process of step (3) slurry canning is as follows: the filtered slurry is injected into a clean, water-free stainless steel storage tank and sealed for storage.

[0031] The filler obtained in Example 1 was added to a waterborne epoxy coating. The proportion of the graphene oxide-based filler in the waterborne epoxy coating was 0.3 wt %. The manufacturer and specification of the waterborne epoxy coating are: Nan Ya Waterborne Epoxy Resin NPEW-291W53 Coating. A waterborne epoxy coating without the filler obtained in Example 1 was used as a blank sample. The water resistance of the waterborne epoxy coating sample was tested according to GB / T 1733, "Determination of Water Resistance of Paint Films."

[0032] The water resistance of waterborne epoxy coatings with the addition of graphene oxide-based fillers was increased from 50 hours to more than 220 hours.

[0033] Example 2:

[0034] In this embodiment, a graphene oxide-based filler and a preparation process thereof include the following steps:

[0035] The slurry preparation process of step (1) is specifically as follows: 30,000 g of deionized water is added to a clean reactor with stirring and heating functions, 100 g of graphene oxide is added while stirring, and after the graphene oxide is evenly dispersed, it is treated with an ultrasonic vibrator for 1.2 hours, followed by adding sodium peroxide and stirring for 30 minutes, and then adding 12 g of dopamine hydrochloride and 13 g of silane coupling agent KH560 and stirring for 30 minutes, heating to 120° C. and stirring for 4 hours, and cooling to room temperature to obtain a slurry.

[0036] The slurry filtration process of step (2) is specifically as follows: the slurry is filtered through a 200-mesh screen to remove substances that cannot be filtered, and the filtered slurry is collected to obtain filtered slurry.

[0037] The specific process of step (3) slurry canning is as follows: the filtered slurry is injected into a clean and water-free tinplate storage tank and sealed for storage.

[0038] The filler obtained in Example 2 was added to a waterborne epoxy coating. The proportion of the graphene oxide-based filler in the waterborne epoxy coating was 1 wt %. The manufacturer and specification of the waterborne epoxy coating were: Nan Ya Waterborne Epoxy Resin NPED-527W53 Coating. A waterborne epoxy coating without the filler obtained in Example 2 was used as a blank sample. The water resistance of the waterborne epoxy coating sample was tested according to GB / T 1733, "Determination of Water Resistance of Paint Films."

[0039] The water resistance of waterborne epoxy coatings with the addition of graphene oxide-based fillers was increased from 50 hours to more than 220 hours.

[0040] Example 3:

[0041] In this embodiment, a graphene oxide-based filler and a preparation process thereof include the following steps:

[0042] The slurry preparation process of step (1) is specifically as follows: 7000 g of deionized water is added to a clean reactor with stirring and heating functions, 100 g of graphene oxide is added while stirring, and after the graphene oxide is evenly dispersed, it is treated with an ultrasonic vibrator for 1 hour, followed by adding 8 g of sodium peroxide and stirring for 30 minutes, and then adding 5 g of dopamine hydrochloride and 5 g of silane coupling agent KH560 and stirring for 30 minutes, heating to 60°C and stirring for 1.5 hours, and cooling to room temperature to obtain a slurry.

[0043] The slurry filtration process in step (2) is specifically as follows: the slurry is filtered through a 160-mesh screen to remove substances that cannot be filtered, and the filtered slurry is collected to obtain filtered slurry.

[0044] The specific process of step (3) slurry canning is as follows: the filtered slurry is injected into a clean, water-free polypropylene plastic storage tank and sealed for storage.

[0045] The filler obtained in Example 3 was added to a waterborne epoxy coating. The proportion of the graphene oxide-based filler in the waterborne epoxy coating was 3 wt %. The manufacturer and specification of the waterborne epoxy coating are: Yuanbang Waterborne Epoxy Resin YPE-20WE0254 Coating. A waterborne epoxy coating without the filler obtained in Example 3 was used as a blank sample. The water resistance of the waterborne epoxy coating sample was tested according to GB / T 1733 "Determination of Water Resistance of Paint Films."

[0046] The water resistance of waterborne epoxy coatings with the addition of graphene oxide-based fillers was increased from 50 hours to more than 220 hours.

[0047] Example 4:

[0048] In this embodiment, a graphene oxide-based filler and a preparation process thereof include the following steps:

[0049] The slurry preparation process of step (1) is specifically as follows: 18,000 g of deionized water is added to a clean reactor with stirring and heating functions, 100 g of graphene oxide is added while stirring, and after the graphene oxide is evenly dispersed, it is treated with an ultrasonic vibrator for 0.5 hour, followed by adding 11 g of sodium peroxide and stirring for 30 minutes, and then adding 10 g of dopamine hydrochloride and 11 g of silane coupling agent KH560 and stirring for 30 minutes, heating to 90° C. and stirring for 2.5 hours, and cooling to room temperature to obtain a slurry.

[0050] The slurry filtration process of step (2) is specifically as follows: the slurry is filtered through a 130-mesh screen to remove substances that cannot be filtered, and the filtered slurry is collected to obtain filtered slurry.

[0051] The specific process of step (3) slurry canning is as follows: the filtered slurry is injected into a clean, water-free fluoroplastic storage tank and sealed for storage.

[0052] The filler obtained in Example 4 was added to a waterborne epoxy coating. The proportion of the graphene oxide-based filler in the waterborne epoxy coating was 0.5 wt %. The manufacturer and specification of the waterborne epoxy coating were: Baling Petrochemical Bisphenol A Waterborne Epoxy Resin CYDW-100 Coating. A waterborne epoxy coating without the filler obtained in Example 4 was used as a blank sample. The water resistance of the waterborne epoxy coating sample was tested according to GB / T 1733, "Determination of Water Resistance of Paint Films."

[0053] The water resistance of waterborne epoxy coatings with the addition of graphene oxide-based fillers was increased from 50 hours to more than 220 hours.

[0054] Example 5:

[0055] In this embodiment, a graphene oxide-based filler and a preparation process thereof include the following steps:

[0056] The slurry preparation process of step (1) is specifically as follows: 20,000 g of deionized water is added to a clean reactor with stirring and heating functions, 100 g of graphene oxide is added while stirring, and after the graphene oxide is evenly dispersed, it is treated with an ultrasonic vibrator for 0.3 hour, followed by adding 12 g of sodium peroxide and stirring for 30 minutes, and then adding 6 g of dopamine hydrochloride and 8 g of silane coupling agent KH560 and stirring for 30 minutes, heating to 110° C. and stirring for 3 hours, and cooling to room temperature to obtain a slurry.

[0057] The slurry filtration process of step (2) is specifically as follows: the slurry is filtered through a 130-mesh screen to remove substances that cannot be filtered, and the filtered slurry is collected to obtain filtered slurry.

[0058] The specific process of step (3) slurry canning is as follows: the filtered slurry is injected into a clean, water-free stainless steel storage tank and sealed for storage.

[0059] The filler obtained in Example 5 was added to a waterborne epoxy coating. The proportion of the graphene oxide-based filler in the waterborne epoxy coating was 1.2 wt %. The manufacturer and specification of the waterborne epoxy coating were DIC Epiclon H-502-42W modified polymer waterborne epoxy resin coating. A waterborne epoxy coating without the filler obtained in Example 5 was used as a blank sample. The water resistance of the waterborne epoxy coating sample was tested according to GB / T 1733, "Determination of Water Resistance of Paint Films."

[0060] The water resistance of waterborne epoxy coatings with the addition of graphene oxide-based fillers was increased from 50 hours to more than 220 hours.

[0061] The implementation results show that the present invention innovatively proposes a graphene-based filler technology. The filler has a main ingredient of graphene oxide and auxiliary materials such as a silane coupling agent, sodium peroxide, dopamine hydrochloride, and deionized water. It is obtained through slurry preparation, slurry filtration, and slurry canning. Insulating silane coupling agents and dopamine hydrochloride are attached to the surface of graphene oxide, which solves the problem of metal corrosion caused by graphene conductivity. Moreover, the silane coupling agent and dopamine hydrochloride attached to the surface of graphene also improve the affinity between graphene and coating resin, thereby comprehensively improving the corrosion resistance of the coating.

Claims

1. A graphene oxide-based filler, characterized in that The graphene oxide-based filler consists of a main material, graphene oxide, and auxiliary materials. Calculated by weight, the main material is 100 parts of graphene oxide, and the auxiliary materials are: 2 to 13 parts of a silane coupling agent, 5 to 12 parts of sodium peroxide, 3 to 12 parts of dopamine hydrochloride, and 5,000 to 30,000 parts of deionized water.

2. The graphene oxide-based filler according to claim 1, characterized in that The graphene oxide is an oxide of graphene, the silane coupling agent is chemically pure, the purity of sodium peroxide is ≥95wt%, the purity of dopamine hydrochloride is ≥97wt%, and the conductivity of deionized water is ≤0.5mS / cm.

3. A process for preparing the graphene oxide-based filler according to claim 1 or 2, characterized in that: The preparation steps are: (1) slurry preparation; (2) slurry filtration; and (3) slurry canning.

4. The preparation process of the graphene oxide-based filler according to claim 3, characterized in that: The slurry preparation process of step (1) is specifically as follows: deionized water is added to a clean reactor with stirring and heating functions, graphene oxide is added while stirring, and after the graphene oxide is evenly dispersed, it is treated with an ultrasonic vibrator for 0.3 to 1.2 hours, and then sodium peroxide is added and stirred for 20 to 40 minutes, and then dopamine hydrochloride and a silane coupling agent are added and stirred for 20 to 40 minutes, heated to 50 to 120° C. and stirred for 1 to 4 hours, and cooled to room temperature to obtain a slurry.

5. The process for preparing the graphene oxide-based filler according to claim 4, wherein: The slurry filtration process in step (2) is specifically as follows: the slurry is filtered through a 120-200 mesh screen to remove substances that cannot be filtered, and the filtered slurry is collected to obtain filtered slurry.

6. The process for preparing the graphene oxide-based filler according to claim 5, wherein: The specific process of step (3) slurry canning is as follows: the filtered slurry is injected into a clean and water-free storage tank and sealed for storage. The storage tank is made of stainless steel, tinplate or plastic.

7. Use of the graphene oxide-based filler according to claim 1 or 2, characterized in that: Graphene oxide-based fillers are used as fillers in water-based coatings, solvent-based coatings, solvent-free coatings or powder coatings.

8. The use of the graphene oxide-based filler according to claim 7, characterized in that: The proportion of the graphene oxide-based filler in the coating is 0.3 to 3 wt%.