FG @ MOF composite material, coating containing composite material, and preparation method and application of composite material

文档序号:931966 发布日期:2021-03-05 浏览:2次 中文

阅读说明:本技术 一种fg@mof复合材料及包含该复合材料的涂料及其制备方法和应用 (FG @ MOF composite material, coating containing composite material, and preparation method and application of composite material ) 是由 高秀磊 窦宝捷 张广志 林修洲 段松 杜勇建 孙金旭 方治文 于 2020-11-26 设计创作,主要内容包括:本发明属于海洋环境下防腐材料技术领域,具体涉及一种FG@MOF复合材料及包含该复合材料的涂料及其制备方法和应用。将FG分散于无水甲醇中,超声震荡,将金属盐和咪唑配体加入到FG甲醇分散液中,搅拌得悬浊液,经离心分离得到固体,用甲醇和去离子水交替洗涤,真空干燥后得到FG@MOF复合材料;将环氧树脂、FG@MOF复合材料和稀释剂混合,球磨搅拌,加入固化剂混匀,得到复合涂料;将复合涂料涂覆在预处理好的金属基体表面,干燥固化后得到复合涂层。通过FG@MOF复合材料对环氧树脂改性,使复合材料中咪唑环与环氧树脂发生化学键合,解决了FG与环氧树脂之间的界面相容性问题,提高了环氧树脂涂层的耐蚀性能与力学性能。(The invention belongs to the technical field of anticorrosive materials in marine environments, and particularly relates to an FG @ MOF composite material, a coating containing the composite material, and a preparation method and application of the coating. Dispersing FG in absolute methanol, ultrasonically oscillating, adding metal salt and imidazole ligand into FG methanol dispersion liquid, stirring to obtain suspension, centrifugally separating to obtain a solid, alternately washing with methanol and deionized water, and drying in vacuum to obtain an FG @ MOF composite material; mixing epoxy resin, FG @ MOF composite material and diluent, ball-milling and stirring, adding curing agent, and uniformly mixing to obtain a composite coating; and (3) coating the composite coating on the surface of the pretreated metal matrix, and drying and curing to obtain the composite coating. Epoxy resin is modified by the FG @ MOF composite material, so that imidazole rings in the composite material are chemically bonded with the epoxy resin, the problem of interface compatibility between FG and the epoxy resin is solved, and the corrosion resistance and the mechanical property of an epoxy resin coating are improved.)

1. An FG @ MOF composite material, which is prepared by the following preparation method: dispersing FG in absolute methanol, ultrasonically oscillating, adding metal salt and imidazole ligand into FG methanol dispersion liquid, stirring to obtain suspension, centrifugally separating to obtain a solid, alternately washing with methanol and deionized water, and then drying in vacuum to obtain the powdered FG @ MOF composite material.

2. The FG @ MOF composite of claim 1, wherein the FG has a degree of fluorination of 10 to 65%, a size of 0.5 to 5 μm, and a thickness of 1 to 10 nm; the metal salt is one or more of zinc nitrate, zinc acetate, zinc chloride, cobalt nitrate or cobalt chloride; the imidazole ligand is one or more of imidazole, 2-methylimidazole, benzimidazole, 2-hydroxybenzimidazole, 2-aminobenzimidazole and 2-mercaptobenzimidazole.

3. The FG @ MOF composite material according to claim 1, wherein the ultrasonic oscillation time is 2-6 hours, the stirring time is 2-3 hours, the washing times are 3-5 times, and the vacuum drying temperature is 60-80 ℃.

4. The FG @ MOF composite of claim 1, wherein the molar ratio of metal salt to imidazole ligand is 1: 1-5; FG accounts for 5-40% of the mass fraction of the raw materials required by the FG @ MOF composite material.

5. An FG @ MOF modified epoxy composite coating comprising the FG @ MOF composite of claim 1, wherein the composite coating comprises the following raw materials: epoxy resin, FG @ MOF composite material, diluent and curing agent.

6. The FG @ MOF modified epoxy composite coating of claim 5, wherein the epoxy resin is one of type E-35, E-44, E-51, or E-55.

7. The FG @ MOF modified epoxy resin composite coating of claim 5, wherein the diluent is a mixture of xylene and n-butanol, and the mass ratio of xylene to n-butanol is 2 to 6: 1; the mass ratio of the epoxy resin, FG @ MOF and the diluent is 10: 0.1-3: 2-10; the mass ratio of the curing agent to the epoxy resin is 1: 2-4, and the curing agent is a polyamide curing agent.

8. The method of making an FG @ MOF modified epoxy composite coating of claim 5, comprising the steps of: and mixing the epoxy resin, the FG @ MOF composite material and the diluent, performing ball milling and stirring for 0.5-5 h, and then adding the curing agent to uniformly mix to obtain the FG @ MOF modified epoxy resin composite coating.

9. The FG @ MOF modified epoxy resin composite coating of claim 5, used in a composite coating, which is prepared by the method comprising: and coating the FG @ MOF modified epoxy resin composite coating on the surface of the pretreated metal matrix, and drying and curing to obtain the FG @ MOF modified epoxy resin composite coating on the surface of the metal matrix.

10. The FG @ MOF modified epoxy composite coating of claim 9, wherein the metal matrix is one of carbon steel, magnesium alloy, aluminum alloy, titanium alloy, or copper alloy; the coating thickness is 30-200 μm, the curing temperature is 30-120 ℃, and the curing time is 60-300 min.

Technical Field

The invention belongs to the technical field of anticorrosive materials in marine environments, and particularly relates to an FG @ MOF composite material, a coating containing the composite material, and a preparation method and application of the coating.

Background

The marine environment is a typical area with high temperature, high humidity, high salt spray and high irradiation, so the marine environment puts very strict requirements on the corrosion resistance of marine engineering materials.

At present, organic coatings are one of the most important anticorrosion means in the marine field. Fluorinated Graphene (FG) is a process in which graphene is fluorinated to form a carbon atom sp2Hybrid conversion to sp3Hybridized and part sp of graphene is reserved2And (5) structure. FG not only retains the characteristics of a graphene two-dimensional plane structure, but also has the characteristics of low surface energy, strong hydrophobicity and high stability given by fluorocarbon bonds, so that the FG has the structural and performance characteristics of two materials, namely graphene and Teflon. Therefore, FG is more corrosion resistant than grapheneThe wear-resistant super-hydrophobic oleophobic fabric has wider application prospect in the fields of wear resistance, super-hydrophobic oleophobic property and the like. However, due to the low surface energy of FG, which is usually physically dispersed inside the coating, there are structural defects such as pores, cracks, etc. between the resin and FG, resulting in a coating against corrosive media (water, Cl)-And oxygen, etc.) and affect the long-term corrosion resistance of the coating. Therefore, how to solve the problem of interfacial compatibility between FG and resin has become a technical problem to be solved urgently by those skilled in the art of corrosion protection.

Disclosure of Invention

Aiming at the problem of interface compatibility between FG and resin in the prior art, the invention provides an FG @ MOF composite material, epoxy resin can be modified through the composite material, imidazole rings in the composite material can be chemically bonded with the epoxy resin, the problem of interface compatibility between FG and the epoxy resin is solved, and the corrosion resistance and the mechanical property of an epoxy resin coating are improved.

An FG @ MOF composite material is prepared by the following preparation method: dispersing FG in absolute methanol, ultrasonically oscillating, adding metal salt and imidazole ligand into FG methanol dispersion liquid, stirring to obtain suspension, centrifugally separating to obtain a solid, alternately washing with methanol and deionized water, and then drying in vacuum to obtain the powdered FG @ MOF composite material.

Further, the FG has a fluorination degree of 10-65%, a size of 0.5-5 μm and a thickness of 1-10 nm; the metal salt is one or more of zinc nitrate, zinc acetate, zinc chloride, cobalt nitrate or cobalt chloride; the imidazole ligand is one or more of imidazole, 2-methylimidazole, benzimidazole, 2-hydroxybenzimidazole, 2-aminobenzimidazole and 2-mercaptobenzimidazole.

FG @ MOF includes FG @ ZIF-8, FG @ ZIF-7 and FG @ ZIF-67, wherein ZIF-8 is synthesized on the basis of Zn salt and dimethyl imidazole, ZIF-7 is synthesized on the basis of Zn salt and benzimidazole, ZIF-67 is synthesized on the basis of Co salt and dimethyl imidazole, ZIF-8, ZIF-7 and ZIF-67 are typical representatives of MOF, and the MOF is obtained by utilizing metal ions and different imidazole ligands for coordination, contains imidazole groups and can perform chemical crosslinking reaction with epoxy resin functional groups.

Further, the ultrasonic oscillation time is 2-6 hours, the stirring time is 2-3 hours, the washing times are 3-5 times, and the vacuum drying temperature is 60-80 ℃.

Further, the molar ratio of the metal salt to the imidazole ligand is 1: 1-5, the particle size of the MOF nano material can be effectively ensured to be 80-200 nm under the molar ratio; the FG accounts for 5-40% of the mass fraction of the raw materials required by the FG @ MOF composite material, and under the proportion, the MOF can be effectively uniformly loaded on the FG surface without being loaded too much to influence the FG performance.

FG @ MOF modified epoxy resin composite coating comprising the FG @ MOF composite material comprises the following raw materials: epoxy resin, FG @ MOF composite material, diluent and curing agent.

Further, the type of the epoxy resin is one of E-35, E-44, E-51 or E-55.

Further, the diluent is a mixture of xylene and n-butyl alcohol, and the mass ratio of the xylene to the n-butyl alcohol is 2-6: 1, the diluent is added to reduce the viscosity of the coating, so that the coating is suitable for a brush coating construction method, the viscosity of the epoxy resin can be reduced by adding dimethylbenzene, and the epoxy resin can be accelerated to be cured by adding n-butyl alcohol; the mass ratio of the epoxy resin, FG @ MOF and the diluent is 10: 0.1-3: 2-10; the mass ratio of the curing agent to the epoxy resin is 1: 2-4, and the curing agent is a polyamide curing agent. The polyamide curing agent is polyamide 650 curing agent, polyamide 651 curing agent, etc.; taking 100g of epoxy resin as an example, the amount of the curing agent is equal to the relative molecular mass of the curing agent/the number of active hydrogen atoms in amine molecules (the number of active hydrogen in the curing agent). times.the epoxy value of the epoxy resin, and the polyamide curing agent is selected to enable the coating to be cured at normal temperature, so that the operability is improved.

The preparation method of the FG @ MOF modified epoxy resin composite coating comprises the following steps: and mixing the epoxy resin, the FG @ MOF composite material and the diluent, performing ball milling and stirring for 0.5-5 h, and then adding the curing agent to uniformly mix to obtain the FG @ MOF modified epoxy resin composite coating.

The FG @ MOF modified epoxy resin composite coating is applied to a composite coating, and the preparation method of the composite coating comprises the following steps: and coating the FG @ MOF modified epoxy resin composite coating on the surface of the pretreated metal matrix, and drying and curing to obtain the FG @ MOF modified epoxy resin composite coating on the surface of the metal matrix.

Further, the metal matrix is one of carbon steel, magnesium alloy, aluminum alloy, titanium alloy or copper alloy; the coating thickness is 30-200 mu m, the curing temperature is 30-120 ℃, and the curing time is 60-300 min.

The invention has the beneficial effects that:

1. according to the FG @ MOF composite material provided by the invention, the adopted fluorinated graphene has a certain oxidation degree, and oxygen-containing functional groups on the surface of FG provide active sites for the growth of the MOF material, so that the controllable growth of MOF on FG is realized. The method can regulate the load of the MOF in the FG @ MOF material, can also utilize different ligands to synthesize the FG @ MOF material with different active hydrogen contents, regulate the crosslinking density between the filler and the epoxy resin, and further synergistically improve the protective performance of the epoxy resin coating.

2. According to the modified fluorinated graphene epoxy resin composite coating provided by the invention, active hydrogen is carried in imidazole rings contained in the MOF, so that the MOF can be subjected to ring-opening reaction with epoxy resin to generate(wherein R is an epoxy chain, R1Is one of methyl, amino, hydroxyl or sulfhydryl, R2Benzene ring or no), so that the epoxy resin and the FG @ MOF composite material are connected by chemical bonds, and the problem of interface compatibility between FG and the epoxy resin is solved; FG gives full play to the barrier effect of the sheet material, while MOF establishes a chemical bridge between FG and resin to enable the composite material to be better dispersed into a resin matrix, thereby increasing the mechanical property of the epoxy resin coating and improving the shielding capability of the epoxy resin coating on corrosive media.

Drawings

In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is an FG @ ZIF-8 scanning electron micrograph of example 1;

FIG. 2 is an FG scanning electron micrograph of comparative example 1;

FIG. 3 is a plot of the low frequency mode impedance values of the coatings of example 1 and comparative example 1;

FIG. 4 is a graph of a neutral salt spray test of the coating of example 1;

FIG. 5 is a graph of a neutral salt spray test for the application of the coating of comparative example 1.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. 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.

Example 1

The preparation method of the FG @ ZIF-8 modified epoxy resin composite coating comprises the following steps:

(1) preparing FG @ ZIF-8 composite material: dispersing 0.117g FG in absolute methanol, ultrasonically oscillating for 2-3 h, and then dispersing 0.5g Zn (NO)3)2·6H2Adding O and 0.55g of 2-methylimidazole into FG methanol dispersion, stirring for 2h to obtain suspension, performing centrifugal separation to obtain suspension, alternately washing with methanol and deionized water for 4 times, and finally drying at 60 ℃ for 12h to obtain a powdered FG @ MOF composite material, wherein the molar ratio of zinc ions to 2-methylimidazole in the example is 1: 4, the mass fraction of FG in all the reaction raw materials is 10 percent;

(2) preparing a composite coating: mixing the components in a mass ratio of 10: 0.5: 8, FG @ ZIF-8 and a diluent, wherein the diluent is a mixture of xylene and n-butyl alcohol, and the mass ratio of the xylene to the n-butyl alcohol is 2: 1; ball-milling and stirring for 0.5h, then adding 40g of polyamide 650 curing agent per 100g of epoxy resin E-44, stirring for 10min, uniformly mixing, and vacuumizing to obtain the FG @ ZIF-8 modified epoxy resin composite coating.

Coating the FG @ ZIF-8 modified epoxy resin composite coating on the surface of a pretreated carbon steel matrix, wherein the coating thickness is 70 +/-10 mu m, drying and curing the coating at the curing temperature of 40 ℃ for 5 hours to obtain a modified epoxy resin coating on the surface of the carbon steel matrix.

Comparative example 1 was carried out

According to the step (2) of the embodiment 1, directly mixing the components in a mass ratio of 10: 0.5: 8, mixing FG and a diluent, wherein the diluent is a mixture of dimethylbenzene and n-butyl alcohol, and the mass ratio of the dimethylbenzene to the n-butyl alcohol is 2: 1; ball-milling and stirring for 0.5h, then adding 40g of polyamide 650 curing agent per 100g of epoxy resin E-44, stirring for 10min, vacuumizing, uniformly mixing to obtain an epoxy resin coating, then coating the epoxy resin coating on the surface of a pretreated carbon steel substrate with the coating thickness of 70 +/-10 mu m, drying and curing at the curing temperature of 40 ℃ for 5h, and obtaining the epoxy resin coating on the surface of the carbon steel.

1. Macroscopic morphology testing of composite materials

The FG @ ZIF-8 and FG used in example 1 and example and comparative example 1 are observed under a scanning electron microscope to obtain morphology results as shown in a figure 1-2, and from the macro morphology and the element analysis of FG @ ZIF-8 in example 1, the ZIF-8 nanometer material is successfully loaded on the FG surface, while the FG surface in example 1 has more folds and shows the surface morphology of typical fluorinated graphene.

2. Electrochemical impedance spectroscopy experiment

The coatings obtained in example 1 and comparative example 1 were subjected to electrochemical impedance spectroscopy in 3.5 wt% NaCl solution, and after 3000h of test, the low-frequency impedance modulus curve is shown in FIG. 3, and the long-term low-frequency impedance modulus of example 1 is always maintained at 1.5X 1011Ω·cm2While the long-term low-frequency impedance modulus value of comparative example 1 was always maintained at 1X 1011Ω·cm2The corrosion resistance of the FG @ ZIF-8 modified epoxy resin coating is improved by 0.5 order of magnitude compared with that of the FG modified epoxy resin coating, and the fact that the load of the ZIF-8 is favorable for improving the dispersion capability of FG in epoxy resin is shown, so that the coating has better corrosion resistance.

3. Neutral salt spray test of coating

When the coatings obtained in example 1 and comparative example 1 were subjected to a salt spray test in a salt spray box containing 5 wt% NaCl as shown in fig. 4 and 5, it can be seen that the FG @ ZIF-8 modified epoxy resin coating of example 1 showed no change in appearance after the salt spray test for 93 days, and showed excellent salt spray resistance; after the FG epoxy resin coating of comparative example 1 was carried out for 30 days, corrosion spots appeared in local areas, probably due to the poor compatibility of the filler with the epoxy resin matrix, so the ZIF-8 load greatly helped the dispersion of FG in the epoxy resin coating, giving the coating better corrosion resistance.

Example 2

The preparation method of the FG @ ZIF-7 modified epoxy resin composite coating comprises the following steps:

(1) preparing FG @ ZIF-7 composite material: dispersing 0.233g FG in absolute methanol, ultrasonically vibrating for 2-3 h, and then dispersing 0.5g ZnCl2And 0.433g of benzimidazole are added into FG methanol dispersion liquid, stirring is carried out for 2 hours to obtain suspension, centrifugal separation is carried out to obtain suspension, methanol and deionized water are used for alternately washing for 4 times, and drying is carried out for 12 hours at 60 ℃ to obtain powdered FG @ MOF composite material, wherein the molar ratio of zinc ions to benzimidazole in the example is 1: 1, the mass fraction of FG in all the reaction raw materials is 20 percent;

(2) preparing a composite coating: mixing the components in a mass ratio of 10: 2: 10, FG @ ZIF-7 and a diluent, wherein the diluent is a mixture of xylene and n-butyl alcohol, and the mass ratio of the xylene to the n-butyl alcohol is 3: 1; ball-milling and stirring for 0.5h, then adding 30g of polyamide 651 curing agent per 100g of epoxy resin E-51, stirring for 10min, uniformly mixing, and vacuumizing to obtain the FG @ ZIF-7 modified epoxy resin composite coating.

And (3) coating the FG @ ZIF-7 modified epoxy resin composite coating on the surface of the pretreated copper alloy matrix, wherein the coating thickness is 100 +/-10 mu m, and then drying and curing the coating at the curing temperature of 60 ℃ for 3h to obtain the modified epoxy resin coating on the surface of the copper alloy matrix.

The low frequency impedance modulus value of the FG @ ZIF-7 modified epoxy resin coating of the embodiment is maintained at 1011Ω·cm2Above, the salt spray resistance can reach 80 days without corrosion spots. The results show that the ZIF-7 load greatly helps the dispersion of FG in the epoxy resin coating, so that the coating has better corrosion resistance.

Example 3

The preparation method of the aminated FG @ ZIF-8 modified epoxy resin composite coating comprises the following steps:

(1) preparing an aminated FG @ ZIF-8 composite material: dispersing 0.8g FG in absolute methanol, ultrasonically oscillating for 2-3 h, and then dispersing 0.5g Zn (NO)3)2·6H2Adding O, 0.3g of 2-methylimidazole and 0.4g of 2-aminobenzimidazole into FG methanol dispersion, stirring for 2 hours to obtain suspension, performing centrifugal separation to obtain suspension, alternately washing with methanol and deionized water for 4 times, and finally drying at 60 ℃ for 12 hours to obtain a powdery aminated FG @ ZIF-8 composite material, wherein the molar ratio of zinc ions to imidazole ligands is 1: 4, the mass fraction of FG in all the reaction raw materials is 40 percent;

(2) preparing a composite coating: mixing the components in a mass ratio of 10: 0.3: 2, mixing the epoxy resin, the aminated FG @ ZIF-8 and a diluent, wherein the diluent is a mixture of xylene and n-butyl alcohol, and the mass ratio of the xylene to the n-butyl alcohol is 3: 1; ball-milling and stirring for 0.5h, then adding 50g of polyamide 650 curing agent per 100g of epoxy resin E-35, stirring for 10min, uniformly mixing, and vacuumizing to obtain the FG @ ZIF-8 modified epoxy resin composite coating.

And (3) coating the FG @ ZIF-8 modified epoxy resin composite coating on the surface of a pretreated 2024 aluminum alloy matrix, wherein the coating thickness is 90 +/-10 mu m, drying and curing the coating at the curing temperature of 80 ℃ for 2h to obtain a modified epoxy resin coating on the surface of the 2024 aluminum alloy matrix.

The low-frequency impedance modulus value of the aminated FG @ ZIF-8 modified epoxy resin coating of the embodiment is maintained at 1011Ω·cm2Above, the salt spray resistance can reach 72 days without corrosion spots. The results show that the load of the aminated ZIF-8 greatly helps the dispersion of FG in the epoxy resin coating, and the crosslinking degree between the filler and the epoxy resin is further improved after the amino is introduced, so that the coating has better corrosion resistance.

Example 4

The preparation method of the FG @ ZIF-67 modified epoxy resin composite coating comprises the following steps:

(1) preparation of FG @ ZIF-67 composite: dispersing 0.082g FG in absolute methanol, carrying out ultrasonic oscillation for 2-3 h, and then dispersing 1g Co (NO)3)2·6H2Adding 0.564g of 2-methylimidazole and O into FG methanol dispersion, stirring for 2h to obtain suspension, performing centrifugal separation to obtain suspension, alternately washing with methanol and deionized water for 4 times, and finally drying at 60 ℃ for 12h to obtain a powdery aminated FG @ ZIF-67 composite material, wherein the molar ratio of cobalt ions to imidazole ligands is 1:2, the mass fraction of FG in all the reaction raw materials is 5 percent;

(2) preparing a composite coating: mixing the components in a mass ratio of 10: 3:2, FG @ ZIF-67 and a diluent, wherein the diluent is a mixture of xylene and n-butyl alcohol, and the mass ratio of the xylene to the n-butyl alcohol is 4: 1; ball-milling and stirring for 0.5h, then adding 50g of polyamide 650 curing agent per 100g of epoxy resin E-35, stirring for 10min, uniformly mixing, and vacuumizing to obtain the FG @ ZIF-67 modified epoxy resin composite coating.

And (3) coating the FG @ ZIF-67 modified epoxy resin composite coating on the surface of the pretreated titanium alloy matrix, wherein the coating thickness is 90 +/-10 mu m, and then drying and curing the coating at the curing temperature of 120 ℃ for 1h to obtain the modified epoxy resin coating on the surface of the titanium alloy matrix.

The low-frequency impedance modulus value of the FG @ ZIF-67 modified epoxy resin coating of the embodiment is maintained at 1011Ω·cm2Above, the salt spray resistance can reach 75 days without corrosion spots. The results show that the ZIF-67 load greatly helps the dispersion of FG in the epoxy resin coating, so that the coating has better corrosion resistance.

Although the present invention has been described in detail by referring to the drawings in connection with the preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made on the embodiments of the present invention by those skilled in the art without departing from the spirit and scope of the present invention, and these modifications or substitutions are within the scope of the present invention/any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

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