Boron nitride / reduced graphene oxide / sodium 1-hydroxyethylidene-1, 1-diphosphonate composite material as well as preparation and application thereof

Abstract

The invention discloses a boron nitride / reduced graphene oxide / sodium 1-hydroxyethylidene-1, 1-diphosphonate composite material as well as a preparation method and application thereof. The preparation method comprises the following steps: carrying out grafting and reduction on hydroxylated boron nitride and modified graphene oxide, and compounding an active factor sodium 1-hydroxyethylidene-1, 1-diphosphonate with boron nitride / reduced graphene oxide to obtain the boron nitride / reduced graphene oxide / sodium 1-hydroxyethylidene-1, 1-diphosphonate composite material. The composite material is used as a coating additive, under the synergistic effect of the three components of the composite material, the cathode protection time can be effectively prolonged, physical shielding is increased, the coating has the self-repairing effect, and the corrosion resistance is improved. Due to the structural characteristics of the boron nitride, the graphene oxide and the active sodium 1-hydroxyethylidene-1, 1-diphosphonate in the composite material and the synergistic effect of the three components and the epoxy zinc powder, the long-acting corrosion resistance is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the field of materials, metal corrosion and protection, and particularly relates to a boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material and a preparation method and application thereof. Background Art

[0002] Metal corrosion is a pressing problem faced by many industries and may cause economic losses. Epoxy zinc-rich coating is a crucial coating in the supporting system of outdoor steel structure anti-corrosion coating. It has excellent comprehensive performance and long-term anti-corrosion performance. Due to its advantages such as easy operation, good adaptability to various substrates, good compatibility with other coatings, and excellent cathodic protection performance, it is widely used as a primer in harsh corrosive environments such as steel storage tanks, ships and marine engineering. Anti-corrosion is generally achieved through various preservatives, and anti-corrosion additives have a great influence on its performance.

[0003] In addition to the advantages of high impermeability, excellent chemical inertness, thermal stability, etc., boron nitride also has insulation properties, which can avoid galvanic corrosion caused by high conductivity. However, due to the difference in electronegativity between B and N atoms in boron nitride, there is a strong interaction between layers, which makes boron nitride easy to aggregate together. Therefore, boron nitride needs to be modified when used. After the introduction of hydroxyl groups on boron nitride, its dispersibility is significantly improved, and the physical barrier properties are fully exerted. Chemically grafted modified boron nitride improves the dispersibility in epoxy resin and the anti-corrosion properties of the composite coating, and is therefore widely used in equipment manufacturing and industrial manufacturing. Graphene and its derivatives have excellent barrier enhancement due to their high specific surface area and excellent impermeability. Electrical connection is an important factor in the cathodic protection of epoxy zinc-rich coatings. Graphene or reduced graphene oxide has excellent conductivity, which improves the electrical connection efficiency between zinc particles and metal substrates. At the same time, the good physical shielding effect of two-dimensional materials in the coating can further enhance the anti-corrosion properties of the coating. However, the anti-corrosion performance of single graphene is not good enough on a macroscopic scale, because its high conductivity also leads to the problem of promoting corrosion. The anti-corrosion performance of the coating is largely restricted by many factors. Summary of the invention

[0004] The object of the present invention is to provide a boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material and a preparation method thereof.

[0005] The technical solution to achieve the purpose of the present invention is:

[0006] In a first aspect, the present invention provides a method for preparing a boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material, comprising the following steps in sequence:

[0007] The first step is to hydrothermally react hydroxylated boron nitride and modified graphene oxide in water, separate and wash them to obtain a boron nitride / reduced graphene oxide composite material;

[0008] In the second step, the active factor sodium hydroxyethylidene diphosphonate is mixed with the boron nitride / reduced graphene oxide composite material, and freeze-dried to obtain the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material.

[0009] Furthermore, hydroxylated boron nitride is obtained by using boron nitride as a raw material, adding sodium hydroxide, reacting at 120° C. for 12 hours, separating, and washing.

[0010] Specifically, the mass ratio of sodium hydroxide to boron nitride is 12:1.

[0011] Furthermore, in order to better chemically compound with hydroxylated boron nitride, the graphene oxide is modified. The modified graphene oxide is obtained by adding a silane coupling agent to a graphene oxide dispersion, reacting at 80° C. for 4 hours, separating, and washing.

[0012] Specifically, the silane coupling agent is an amino-containing silane coupling agent, such as γ-aminopropyltriethoxysilane.

[0013] Specifically, the mass ratio of the silane coupling agent to the graphene oxide is 3:1.

[0014] Furthermore, the reaction was carried out hydrothermally in water at 180°C for 8 h.

[0015] Furthermore, the mass ratio of modified graphene oxide to hydroxylated boron nitride is 2:1.

[0016] Furthermore, the mass ratio of the active factor sodium hydroxyethylidene diphosphonate to the boron nitride / reduced graphene oxide composite material is 2:3.

[0017] In a second aspect, the present invention provides a boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material prepared by the method described in the first aspect.

[0018] In a third aspect, the present invention provides an epoxy zinc-containing coating, which at least comprises an additive, an epoxy resin, zinc powder, and a curing agent, wherein the additive is a boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material prepared by the method described in the first aspect.

[0019] Furthermore, the solid content of the additive in the epoxy zinc-containing coating is 0.1-1.0%.

[0020] Furthermore, the solid content of zinc powder in the epoxy zinc-containing coating is 50-70%.

[0021] In a fourth aspect, the present invention provides an epoxy zinc-containing coating, which is obtained by coating the coating described in the third aspect.

[0022] Compared with the prior art, the present invention has the following significant advantages: (1) a composite material of hydroxylated boron nitride, reduced graphene oxide and sodium hydroxyethylidene diphosphonate is prepared by a covalent grafting and adsorption method; (2) the structural characteristics of the three, such as a two-dimensional nanostructure, an electronic conductor and abundant metal coordination groups, endow the composite material with a multifunctional effect as an anti-corrosion coating additive; (3) the solid coating containing the composite material of boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate of the present invention has excellent anti-corrosion performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a process flow chart for preparing boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material.

[0024] Figure 2 Transmission electron microscopy image of boron nitride / reduced graphene oxide composite material.

[0025] Figure 3 The graphs are Log (resistance modulus) - Log (frequency) of the coatings in Examples 1-4 and Comparative Examples 1-5 on the 10th day of immersion. DETAILED DESCRIPTION

[0026] The present application is further described below in conjunction with specific embodiments.

[0027] It should be noted that the terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of description and are not used to limit the scope of implementation. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of this application without substantially changing the technical content.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0029] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0030] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement or value. The degree of flexibility for a particular variable can be easily determined by one skilled in the art.

[0031] As used herein, the term "at least one of" is intended to be synonymous with "one or more of." For example, "at least one of A, B, and C" expressly includes only A, only B, only C, and combinations of each thereof.

[0032] Concentration, amount and other numerical data can be presented in range format herein.It should be understood that such range format is only used for convenience and simplicity, and should be flexibly interpreted as not only including the numerical value clearly described as range limit, but also including all single numerical values ​​or sub-ranges contained in the range, just as each numerical value and sub-range are clearly described.For example, the numerical range of about 1 to about 4.5 should be interpreted as not only including the limit value of 1 to about 4.5 clearly described, but also including single numerals (such as 2,3,4) and sub-ranges (such as 1 to 3,2 to 4, etc.).The same principle is applicable to the scope of only narrating a numerical value, such as "less than about 4.5", which should be interpreted as including all the above-mentioned values ​​and ranges.In addition, no matter how the breadth of the described range or feature is, this explanation should be applicable.

[0033] The process of preparing the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material according to the present invention is shown in Figure 1 .

[0034] The present invention composites reduced graphene oxide with other materials, and solves the problem of metal corrosion in seawater by means of the synergistic effect between different component materials to achieve more outstanding anticorrosion performance. Active factor sodium hydroxyethylidene diphosphonate is an organic phosphonic acid compound, which can form a protective film with metal ions in seawater and zinc in coating (forming coordination compounds with calcium, magnesium, zinc ions), covering the surface of the metal substrate to effectively prevent oxygen, water and other corrosive media from directly contacting the metal substrate, thereby reducing the corrosion of the metal substrate. In addition, sodium hydroxyethylidene diphosphonate is not easily degraded by microorganisms, and this characteristic is particularly important for equipment that needs to be used in water. Compared with some traditional preservatives, active factor sodium hydroxyethylidene diphosphonate is considered to be more environmentally friendly because it has less impact on the environment and the decomposition products are relatively harmless.

[0035] Electrochemical test: Donghua electrochemical workstation, model CHI920D, was used. The prepared coating sample was immersed in 3.5wt% NaCl solution as the working electrode, Ag / AgCl electrode as the reference electrode, and platinum sheet as the auxiliary electrode to conduct electrochemical impedance spectroscopy test of electrochemical corrosion. The specific conditions were: frequency of 100kHz~0.01Hz, amplitude of 20mV.

[0036] Example 1

[0037] (1) Take 500 mg of boron nitride and add it to 10 mL of deionized water and ultrasonicate it. Take 6 g of sodium hydroxide solid and slowly add it to 30 mL of deionized water. Add the boron nitride solution to the prepared sodium hydroxide solution, stir, ultrasonicate it, pour it into a polytetrafluoroethylene reactor, and react it at 120°C for 12 hours. Separate, wash, and freeze-dry to obtain hydroxylated boron nitride.

[0038] (2) Take 10g of graphene oxide dispersion with a solid content of 10.5mg / g, add it to 80mL of deionized water and ultrasonicate. Take 315mg of silane coupling agent (KH550), add it to 20mL of deionized water while stirring. Slowly add the pre-hydrolyzed silane coupling agent solution dropwise to the graphene oxide dispersion and react at 80℃ for 4h. Separate and wash to obtain modified graphene oxide.

[0039] (3) The hydroxylated boron nitride obtained in (1) and the modified graphene oxide obtained in (2) were ultrasonically reacted in deionized water at a mass ratio of 1:2 for 2 h, poured into a polytetrafluoroethylene reactor, reacted at 180° C. for 8 h, separated, and washed to obtain a boron nitride / reduced graphene oxide composite material, the transmission electron microscopy image of which is shown in FIG. Figure 2 As shown, hydroxylated boron nitride exists in the form of flakes and is arranged on the flakes of reduced graphene oxide.

[0040] (4) Sodium hydroxyethylidene diphosphonate and boron nitride / reduced graphene oxide are mixed in a mass ratio of 2:3, and the mixture is freeze-dried to obtain a boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material.

[0041] (5) 0.1% (based on the solid content of the coating) of the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material is taken as an additive and epoxy resin E51, 63% (based on the solid content of the coating) of zinc powder and a curing agent to prepare a coating. The specific process is as follows: 0.0055g of the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material in (4) is dissolved in 1g of xylene solution and ultrasonically stirred for 1h. Then, 1g of epoxy resin E51 and 3.5g of zinc powder are added and stirred for 2h, and 1g of curing agent (polyamide 650) is added and stirred for 10min.

[0042] (6) Coating preparation process: Select 10×20 mm tinplate, polish it with water-resistant sandpaper, and clean it with ethanol ultrasonic. Apply the coating prepared in (5) evenly on the 10×20 mm tinplate. The coating is cured at 80°C for 4 hours.

[0043] The low-frequency impedance modulus of the electrochemical impedance spectrum of the coating after 10 days of immersion is shown in Figure 3 Its low frequency impedance modulus is 9.91E+06Ω·cm 2, which is 81.58 times higher than that of comparative example 1. The test results are given in Table 1.

[0044] Example 2

[0045] The other processes are the same as those in Example 1, except that in step (5), the amount of the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material is changed to 0.0275 g, that is, the solid content of the composite material additive is 0.5%.

[0046] according to Figure 3 It can be seen that the low-frequency impedance modulus of the coating is 1.55E+08Ω·cm 2 , which is 1290.66 times higher than that of comparative example 1. The test results are given in Table 1.

[0047] Example 3

[0048] The other processes are the same as those in Example 1, except that in step (5), the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material is changed to 0.0550 g, that is, the solid content of the composite material additive is 1%.

[0049] according to Figure 3 It can be seen that the low-frequency impedance modulus of the coating is 6.04E+07Ω·cm 2 , which is 502.33 times higher than that of comparative example 1. The test results are given in Table 1.

[0050] Example 4

[0051] The other processes are the same as those in Example 1, except that in step (5), the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material is changed to 0.0205 g, and the zinc powder is changed to 2 g, that is, the solid content of the composite material additive is 0.5%, and the solid content of the zinc powder is 50%.

[0052] according to Figure 3 It can be seen that the low-frequency impedance modulus of the coating is 3.55E+07Ω·cm 2 , which is 294.83 times higher than that of comparative example 1. The test results are given in Table 1.

[0053] Comparative Example 1

[0054] For comparison, a coating without the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material additive was prepared. The process for preparing the coating was the same as step (5) of Example 1, except that the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material was changed to 0 g.

[0055] according to Figure 3 It can be seen that the low-frequency impedance modulus of the coating is 1.20E+05Ω·cm 2 The test results are given in Table 1.

[0056] Comparative Example 2

[0057] For comparison, a coating was prepared using a boron nitride / reduced graphene oxide composite material as an additive. The process for preparing the coating was the same as step (5) of Example 1, except that the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material was replaced with the boron nitride / reduced graphene oxide composite material prepared in step (3).

[0058] according to Figure 3 It can be seen that the low-frequency impedance modulus of the coating is 2.67E+06Ω·cm 2 , which is 21.25 times higher than that of comparative example 1. The test results are given in Table 1.

[0059] Comparative Example 3

[0060] (1) Take 500 mg of boron nitride and add it to 10 mL of deionized water for ultrasonic treatment. Take 6 g of sodium hydroxide solid and slowly add it to 30 mL of deionized water. Add the boron nitride solution to the prepared sodium hydroxide solution, stir, ultrasonicate, pour into a polytetrafluoroethylene reactor, and react at 120°C for 12 hours. Separate and clean. Mix sodium hydroxyethylidene diphosphonate and hydroxylated boron nitride in a mass ratio of 1:1, and freeze-dry to obtain a boron nitride / sodium hydroxyethylidene diphosphonate composite material.

[0061] (2) The process is the same as step (5) and step (6) of Example 1, except that the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material is replaced by a boron nitride / sodium hydroxyethylidene diphosphonate composite material.

[0062] according to Figure 3 It can be seen that the low-frequency impedance modulus of the coating is 2.57E+05Ω·cm 2 , which is 1.14 times higher than that of comparative example 1. The test results are given in Table 1.

[0063] Comparative Example 4

[0064] (1) Take 10g of graphene oxide dispersion with a solid content of 10.5mg / g, add it to 80mL of deionized water and ultrasonicate. Take 315mg of silane coupling agent (KH550) and add it to 20mL of deionized water while stirring. Slowly add the pre-hydrolyzed silane coupling agent solution dropwise to the graphene oxide dispersion and react at 80℃ for 4h. Separate and wash to obtain modified graphene oxide. Mix sodium hydroxyethylidene diphosphonate and modified graphene oxide in a mass ratio of 1:1, and obtain modified graphene oxide / sodium hydroxyethylidene diphosphonate composite material after freeze-drying.

[0065] (2) The process is the same as step (5) and step (6) of Example 1, except that the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material is replaced by a modified graphene oxide / sodium hydroxyethylidene diphosphonate composite material.

[0066] according to Figure 3 It can be seen that the low-frequency impedance modulus of the coating is 4.97E+05Ω·cm 2 , which is 3.14 times higher than that of comparative example 1. The test results are given in Table 1.

[0067] Comparative Example 5

[0068] The other processes are the same as those in Example 2, except that the boron nitride / reduced graphene oxide composite material in step (3) is not prepared by a hydrothermal method, but by a physical mixing method, that is, hydroxylated boron nitride and modified graphene oxide are ultrasonically stirred in deionized water at a mass ratio of 1:2 for 2 hours, and then washed to obtain a physically mixed boron nitride / modified graphene oxide composite material.

[0069] according to Figure 3 It can be seen that the low-frequency impedance modulus of the coating is 8.22E+05Ω·cm 2 , which is 5.85 times higher than that of comparative example 1. The test results are given in Table 1.

[0070] Table 1 Low-frequency impedance modulus values ​​of composite anti-corrosion coatings under different examples

[0071]

[0072] The above-mentioned implementation cases are only preferred implementation cases in the present invention, but the implementation methods of the present invention are not limited to the above-mentioned implementation cases. For example, various forms of combinations of the schemes in the embodiments, any other changes, modifications, substitutions, and combinations made without departing from the spirit and principles of the present invention should be equivalent replacement methods and are within the protection scope of the present invention.

Claims

1. A method for preparing a boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material, characterized in that: The following steps are involved: The first step is to hydrothermally react hydroxylated boron nitride and modified graphene oxide in water, separate and wash them to obtain a boron nitride / reduced graphene oxide composite material; In the second step, the active factor sodium hydroxyethylidene diphosphonate is mixed with the boron nitride / reduced graphene oxide composite material, and freeze-dried to obtain the boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material.

2. The method according to claim 1, characterized in that Hydroxylated boron nitride is obtained by taking boron nitride as raw material, adding sodium hydroxide, reacting at 120°C for 12 hours, separating and washing.

3. The method according to claim 1, characterized in that The modified graphene oxide is obtained by adding a silane coupling agent to a graphene oxide dispersion, reacting at 80° C. for 4 h, separating, and washing.

4. The method according to claim 1, characterized in that The reaction was carried out in water at 180 °C for 8 h.

5. The method according to claim 1, characterized in that The mass ratio of modified graphene oxide to hydroxylated boron nitride is 2:

1.

6. The method according to claim 1, characterized in that The mass ratio of sodium hydroxyethylidene diphosphonate to boron nitride / reduced graphene oxide composite material is 2:

3.

7. A boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material prepared by the method according to any one of claims 1 to 6.

8. An epoxy zinc-containing coating, characterized in that: The invention at least comprises an additive, an epoxy resin, zinc powder and a curing agent, wherein the additive is a boron nitride / reduced graphene oxide / sodium hydroxyethylidene diphosphonate composite material prepared by the method according to any one of claims 1 to 6.

9. The coating according to claim 8, characterized in that The solid content of the additive in the epoxy zinc-containing paint is 0.1-1.0%.

10. An epoxy zinc-containing coating, which is obtained by coating the coating according to claim 8 or 9.

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