阅读说明：本技术 基于石墨烯水滑石纳米容器耐蚀水性环氧涂层及制备方法 (Graphene hydrotalcite nano container based corrosion-resistant waterborne epoxy coating and preparation method thereof ) 是由 张达威 王鑫 钱鸿昌 马菱薇 李晓刚 于 2020-07-07 设计创作，主要内容包括：一种基于石墨烯水滑石纳米容器耐蚀水性环氧涂层及制备方法,属于耐蚀涂层材料领域。该水性涂层由氧化石墨烯和水滑石纳米材容器组成的复合填料(GO@LDH)和缓蚀剂及固化剂组成；所述石墨烯材料为氧化石墨烯；所述水滑石纳米容器(LDH)为六水硝酸镁、九水硝酸铝混合而成；负载的缓蚀剂材料为偏钒酸盐。制备过程是将负载缓蚀剂的水滑石纳米容器和氧化石墨烯通过静电自组装得到复合填料,添加于水性环氧树脂中然后加入固化剂,而后将制备好的涂层混合液涂刷于铝合金基底上。本发明制备工艺简单,水滑石纳米容器(LDH)负载了缓蚀剂可在腐蚀发生时实现缓蚀剂的释放,提高了涂层的防腐性能。并且填料中的氧化石墨烯具有良好的屏蔽性能,使得水性环氧涂层具有优异的防腐性能。(A graphene hydrotalcite nanocontainer-based corrosion-resistant waterborne epoxy coating and a preparation method thereof belong to the field of corrosion-resistant coating materials. The water-based coating consists of a composite filler (GO @ LDH) consisting of graphene oxide and a hydrotalcite nano material container, a corrosion inhibitor and a curing agent; the graphene material is graphene oxide; the hydrotalcite nano container (LDH) is formed by mixing magnesium nitrate hexahydrate and aluminum nitrate nonahydrate; the supported corrosion inhibitor material is metavanadate. The preparation process comprises the steps of carrying out electrostatic self-assembly on a hydrotalcite nano container loaded with a corrosion inhibitor and graphene oxide to obtain a composite filler, adding the composite filler into aqueous epoxy resin, then adding a curing agent, and then brushing the prepared coating mixed solution on an aluminum alloy substrate. The preparation process is simple, and the hydrotalcite nano container (LDH) loaded with the corrosion inhibitor can realize the release of the corrosion inhibitor when corrosion occurs, thereby improving the corrosion resistance of the coating. And the graphene oxide in the filler has good shielding performance, so that the water-based epoxy coating has excellent corrosion resistance.)

1. A graphene-hydrotalcite-based nano container corrosion-resistant waterborne epoxy coating comprises a composite filler (GO @ LDH) composed of graphene oxide and a hydrotalcite nano container, a corrosion inhibitor and a curing agent; the graphene material is graphene oxide; the hydrotalcite nano container (LDH) is formed by mixing magnesium nitrate hexahydrate and aluminum nitrate nonahydrate; in the composite filler, the graphene oxide accounts for 2-5% by mass, the hydrotalcite nano container (LDH) accounts for 95-98% by mass, and the ratio of magnesium nitrate hexahydrate to aluminum nitrate nonahydrate in the hydrotalcite nano container is 3: 1; the supported corrosion inhibitor material is metavanadate.

2. The preparation method of the graphene hydrotalcite nanocontainer-based corrosion-resistant waterborne epoxy coating according to claim 1, wherein the composite filler is prepared by electrostatic self-assembly of the hydrotalcite nanocontainer loaded with the corrosion inhibitor and graphene oxide, the composite filler is added into the waterborne epoxy resin, then the curing agent is added, and then the prepared coating mixed solution is coated on the aluminum alloy substrate.

3. The preparation method of the graphene hydrotalcite nano container based corrosion-resistant water-based epoxy coating as claimed in claim 2, wherein the addition amount of the composite filler (GO @ LDH) composed of the graphene oxide and the hydrotalcite nano container (LDH) in the coating mixed solution is 0.2-1 wt%.

4. The preparation method of the graphene hydrotalcite nanocontainer-based corrosion-resistant waterborne epoxy coating according to claim 2, which comprises the following specific steps:

(1) the preparation method of the composite filler consisting of the graphene oxide and the hydrotalcite nano container comprises the following steps: placing Graphene Oxide (GO) in absolute ethyl alcohol by adopting an ultrasonic dispersion method, and performing ultrasonic dispersion to obtain oxygenDissolving a graphene dispersion liquid; mixing magnesium nitrate hexahydrate (Mg (NO)₃)₂.6H₂O), aluminum nitrate nonahydrate (Al (NO)₃)₃.9H₂O) mixing the components according to the ratio of 3:1, then mixing the mixture with the dispersion liquid, and violently stirring the mixture for 0.5 to 1.5 hours at room temperature to obtain a precursor liquid; mixing sodium nitrate (NaNO)₃) Adding the mixture into the precursor solution, adjusting the pH to 9-11 by using sodium hydroxide, reacting at 70-100 ℃, washing, centrifuging and drying in vacuum; adding dried powder into sodium metavanadate (NaVO)₃) Ion exchange is carried out in the solution, the pH value is adjusted to 8.4, and the reaction is carried out for 20 to 28 hours at the temperature of between 30 and 50 ℃. Then washing, centrifuging and drying, and storing for later use;

(2) the preparation method of the water-based epoxy coating comprises the following steps: uniformly dispersing a composite filler consisting of graphene oxide and a hydrotalcite nano container (LDH) loaded with a corrosion inhibitor in absolute ethyl alcohol, adding a turbid liquid into aqueous epoxy resin, performing rotary evaporation to remove excess ethyl alcohol, adding an amine curing agent after a period of time, wherein the amine curing agent accounts for 30% of the mass of a coating, and magnetically stirring at room temperature for 15-30 min; and uniformly coating the prepared coating mixed solution on an aluminum alloy substrate by using a bar scraping method, and then curing for 24-36 h at 50 ℃ to obtain the water-based epoxy coating with the thickness of 50-100 mu m.

Technical Field

The invention belongs to the field of corrosion-resistant coating materials, and relates to a corrosion-resistant water-based epoxy coating based on a graphene hydrotalcite nano-container compound and a preparation method thereof.

Background

The organic coating is used as an important means for metal protection, and protects metal through a physical shielding effect so as to inhibit the occurrence of corrosion phenomenon on the surface of a metal substrate and prevent the metal substrate from being damaged by corrosion. However, most of the traditional organic coatings are solvent-based, and have the defects of toxic and volatile solvent, resource waste, environmental pollution and the like, and are contrary to the current environmental-friendly concept. In recent years, non-toxic and pollution-free aqueous coatings have attracted much attention. However, compared with the traditional solvent-based organic coating, the water-based coating has poor corrosion resistance. Usually, nano-filler is added into waterborne epoxy resin to improve the corrosion resistance of the coating, and particularly, a composite material containing layered micro-nano filler is added. Or the corrosion inhibitor is directly added into the waterborne epoxy to obtain the self-repairing performance to improve the corrosion resistance of the waterborne epoxy. However, since side reactions may occur between the corrosion inhibitor and the resin matrix, in order to avoid the side reactions, the corrosion inhibitor is generally encapsulated using a nano-container.

One of the main uses of graphene in the field of corrosion prevention is to disperse graphene as filler particles into a coating matrix to form a graphene composite anticorrosive coating. But graphene is easy to agglomerate in the coating layer, so that the shielding performance of the graphene is damaged.

Disclosure of Invention

The invention aims to improve the dispersion performance of graphene through hydrotalcite nano-container intercalation so as to improve the shielding performance of the graphene, and combine the graphene with the effect of releasing the corrosion inhibitor of the hydrotalcite nano-container, solve the problem of poor shielding performance of the existing water-based coating, and improve the corrosion resistance of the water-based coating.

The graphene-hydrotalcite nano container-based corrosion-resistant waterborne epoxy coating comprises a composite filler (GO @ LDH) composed of graphene oxide and a hydrotalcite nano container, a corrosion inhibitor and a curing agent. The graphene material is graphene oxide; the hydrotalcite nano container (LDH) is formed by mixing magnesium nitrate hexahydrate and aluminum nitrate nonahydrate. In the composite filler, the graphene oxide accounts for 2-5% by mass, the hydrotalcite nano container (LDH) accounts for 95-98% by mass, and the ratio of magnesium nitrate hexahydrate to aluminum nitrate nonahydrate in the hydrotalcite nano container is 3: 1; the supported corrosion inhibitor material is metavanadate.

The preparation method of the corrosion-resistant waterborne epoxy coating based on the graphene hydrotalcite nanocapsule comprises the following steps: preparing a composite filler by electrostatic self-assembly of a hydrotalcite nano container loaded with a corrosion inhibitor and graphene oxide, adding the composite filler into aqueous epoxy resin, adding a curing agent, and brushing the prepared coating mixed solution on an aluminum alloy substrate.

Furthermore, the addition amount of a composite filler (GO @ LDH) composed of the graphene oxide and the hydrotalcite nano container (LDH) in the coating mixed solution is 0.2-1 wt%.

The preparation method of the corrosion-resistant waterborne epoxy coating based on the graphene hydrotalcite nano container comprises the following specific preparation steps:

(1) the preparation method of the composite filler (GO @ LDH) composed of the graphene oxide and the hydrotalcite nano container (LDH) comprises the following steps: placing Graphene Oxide (GO) in absolute ethyl alcohol by an ultrasonic dispersion method, and performing ultrasonic dispersion to obtain a graphene oxide dispersion liquid; mixing magnesium nitrate hexahydrate (Mg (NO)₃)₂.6H₂O), aluminum nitrate nonahydrate (Al (NO)₃)₃.9H₂O) mixing the components according to the ratio of 3:1, then mixing the mixture with the dispersion liquid, and violently stirring the mixture for 0.5 to 1.5 hours at room temperature to obtain a precursor liquid; mixing sodium nitrate (NaNO)₃) Adding the mixture into the solution, adjusting the pH value to 9-11 by using sodium hydroxide, reacting at 70-100 ℃, washing, centrifuging and drying in vacuum; adding dried powder into sodium metavanadate (NaVO)₃) Ion exchange is carried out in the solution, the pH value is adjusted to about 8.4, and the reaction is carried out for 20 to 28 hours at the temperature of between 30 and 50 ℃. And then washing, centrifuging, drying and storing for later use.

(2) The preparation method of the water-based epoxy coating comprises the following steps: uniformly dispersing a composite filler consisting of graphene oxide and a hydrotalcite nano container (LDH) loaded with a corrosion inhibitor in absolute ethyl alcohol, adding a turbid liquid into aqueous epoxy resin, performing rotary evaporation to remove excess ethyl alcohol, adding an amine curing agent after a period of time, wherein the amine curing agent accounts for 30% of the mass of the coating, and magnetically stirring for 15-30 min at room temperature. And uniformly coating the prepared coating mixed solution on an aluminum alloy substrate by using a bar scraping method, and then curing for 24-36 h at 50 ℃ to obtain the water-based epoxy coating with the thickness of 50-100 mu m.

The invention has the following advantages:

(1) the composite filler GO @ LDH consisting of the hydrotalcite (LDH) nano container and the graphene oxide is prepared by a coprecipitation method, and the preparation process is simple.

(2) The hydrotalcite nano container (LDH) is loaded with the corrosion inhibitor, so that the release of the corrosion inhibitor can be realized when corrosion occurs, a certain protection effect is realized on a corrosion area, and the corrosion resistance of the coating can be improved to a certain extent. And the graphene oxide in the filler has good shielding performance, and the water-based epoxy coating has excellent corrosion resistance due to the synergistic effect of the graphene oxide and the graphene oxide.

Drawings

FIG. 1 is a schematic diagram of EIS testing comparing before and after 30 days soaking of an aqueous epoxy coating with 0.2 wt% hydrotalcite nano-container (LDH) added and an aqueous epoxy coating with 0.2 wt% GO @ LDH composite filler added.

FIG. 2 is a schematic diagram of EIS tests comparing aqueous epoxy coatings with 0.5 wt% Graphene Oxide (GO) added and 0.5 wt% GO @ LDH composite filler added after 60 days soaking.

FIG. 3 is a schematic diagram of EIS testing comparing a typical purely aqueous epoxy coating and an aqueous epoxy coating with 1.0 wt% GO @ LDH composite filler added before and after 60 days immersion.

Detailed Description

For a better understanding of the present invention, the present invention will be further described with reference to the accompanying drawings and examples, but the embodiments of the present invention are not limited thereto.