A nanofiber toughened organic coating doped with hydrophobic particles, and methods of making and using the same

Abstract

The application provides a kind of nanofiber toughened organic coating doped with hydrophobic particles and its preparation method and application.The organic coating includes a nanofiber layer and a resin layer;The nanofiber layer includes nanofibers and modified hydrophobic particles;The resin layer includes organic resin and curing agent;The resin layer is coated on the substrate, and the nanofiber layer is formed on the resin layer;The modified hydrophobic particles are doped in the nanofibers.The organic coating of the application is composed of polyvinylidene fluoride nanofibers, modified particles, organic resin and curing agent;Among them, the modified particles are doped in the nanofibers by electrospinning technology, and then the nanofibers are collected on the metal substrate coated with an organic resin coating to synergistically protect the metal substrate.It is simple to make, low in cost, and the coating has multiple excellent properties such as high resistance, high toughness, hydrophobicity, etc., outstanding durability, and great application prospects in marine corrosion protection.

Description

Technical Field

[0001] This invention belongs to the technical field of anti-corrosion protective film materials, specifically relating to a nanofiber toughened organic coating doped with hydrophobic particles, its preparation method, and its application. Background Technology

[0002] Covering metal surfaces with various protective coatings to isolate the protected metal from corrosive media is an effective method for inhibiting corrosion of metallic materials. Organic coatings are formed by applying organic paints or plastics to the surface of parts using methods such as brushing, dipping, spraying, electrophoretic coating, and electrostatic spraying, followed by curing. Anti-corrosion coatings are the most common and effective protective technology for metallic materials, widely used in marine, chemical, transportation, and shipbuilding industries. With the continuous advancement of coating technology, a wide variety of anti-corrosion coating products have emerged. However, organic coatings inevitably develop cracks or defects during use. Some small-molecule corrosive media (such as water and chloride ions) can reach the protected substrate through these cracks or defects, causing corrosion. Once corrosion begins, it accelerates the peeling of the coating from the metal substrate until it is completely peeled off, thus losing its protective effect. Therefore, improving the inherent defects of resin coatings and enhancing their anti-corrosion performance to expand their application range is particularly important.

[0003] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0004] To address the shortcomings of existing coatings, the main objective of this invention is to provide a nanofiber-toughened organic coating doped with hydrophobic particles, its preparation method, and its application. This coating exhibits good toughness and strong protective capabilities.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a nanofiber-toughened organic coating doped with hydrophobic particles. The organic coating includes a nanofiber layer and a resin layer. The nanofiber layer includes nanofibers and modified hydrophobic particles. The resin layer includes an organic resin and a curing agent. The resin layer is coated on a substrate, and the nanofiber layer is formed on the resin layer. The modified hydrophobic particles are doped into the nanofibers.

[0007] Preferably, the mass ratio of the modified hydrophobic particles to the nanofibers is 1:1-3.

[0008] Preferably, the nanofibers comprise ≥5% of the total organic coating by mass percentage.

[0009] Preferably, the nanofibers are polyvinylidene fluoride with a diameter of 300-500 nm;

[0010] The modified hydrophobic particles are hydrophobic particles treated with a modifier;

[0011] The organic resin is epoxy resin, polyurethane resin, or fluorocarbon resin;

[0012] The curing agent is an epoxy resin curing agent, a polyurethane resin curing agent, or a fluorocarbon resin curing agent;

[0013] The substrate is a metal substrate.

[0014] Preferably, the weight ratio of the organic resin to the curing agent is 1-2:1;

[0015] The hydrophobic particles are natural clay particles with a particle size of 5-30 μm, and the natural clay particles are sepiolite particles or kaolin particles; the modifier is an aliphatic modifier or a silane coupling agent modifier.

[0016] Preferably, the mass ratio of the natural clay particles to the aliphatic modifier is 1:0.5-1; and the mass ratio of the natural clay particles to the silane coupling agent modifier is 1:0.05-0.2.

[0017] Preferably, the aliphatic modifier is myristic acid, cinnamic acid, or stearic acid;

[0018] The silane coupling agent modifier is hexadecyltrimethoxysilane, octadecyltrimethoxysilane, or 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0019] This invention provides a method for preparing the aforementioned nanofiber-toughened organic coating, comprising the following steps:

[0020] Step 1: Preparation of modified hydrophobic particles:

[0021] Hydrophobic particles were dissolved in an ethanol solution, stirred evenly, and then a modifier was added. The mixture was heated and stirred, then washed, dried, and sieved to obtain modified hydrophobic particles.

[0022] Step 2: Preparation of nanofiber spinning solution:

[0023] Nanofibers are dissolved in an organic solvent to obtain a spinning solution; the modified hydrophobic particles obtained in step one are added to the spinning solution and stirred to obtain a nanofiber spinning solution.

[0024] Step 3: Preparation of the resin-coated metal substrate:

[0025] The organic resin is mixed with a curing agent and uniformly coated onto the surface of a metal substrate. The mixture is then dried until the organic resin reaches a surface-dry state, thus obtaining a metal substrate coated with resin.

[0026] Step 4: Preparation of toughened organic coating doped with superhydrophobic particles:

[0027] The nanofiber spinning solution obtained in step two is drawn into a syringe, the syringe is fixed on an electrostatic coaxial spinning machine, and the needle is connected to the positive and negative power supply; an aluminum foil is placed on the collector, and the resin-coated metal substrate obtained in step three is fixed on the aluminum foil; electrospinning is then performed to obtain the nanofiber.

[0028] Preferably, in step one, the mass ratio of hydrophobic particles to modifier is 1:0.05-1; the mass ratio of hydrophobic particles to ethanol solution is 3-12g:20-80mL.

[0029] After adding the modifier, first heat to 40-50℃, stir for 10-14h after reaching the target temperature, then stir at room temperature for 5-7h, then filter and wash three times with ethanol, and dry the obtained powder in an oven at 60-80℃ for 24h.

[0030] Step 2, the organic solvent is N,N-methylformamide; the mass ratio of nanofibers to the volume ratio of organic solvent is 3-9 g: 20-60 mL; the mass ratio of modified hydrophobic particles to nanofibers is 1:1-3;

[0031] The temperature for step two is 23-26℃, and the humidity is 35%-50%; the modified hydrophobic particles are added to the spinning solution and stirred for 22-26 hours.

[0032] Step 3: The mass ratio of organic resin to curing agent is 1-2:1;

[0033] The coating thickness on the metal substrate surface is 30-50 μm; the drying temperature is 50-70℃, and the drying time is 15-25 min.

[0034] Step 4: During electrospinning, the temperature is 20-28℃, the humidity is 20%-40%, the spinning voltage is 20-25kV, the push speed of the injection pump is 0.05-0.1mm / min, and the spinning time is 1-8h.

[0035] This invention provides an application of the aforementioned nanofiber toughened organic coating in metal corrosion protection.

[0036] Beneficial effects:

[0037] The organic coating of this invention consists of polyvinylidene fluoride nanofibers, modified particles, organic resin, and a curing agent. The modified particles are incorporated into the nanofibers using electrospinning technology. The nanofibers are then collected on a metal substrate coated with the organic resin, enabling synergistic protection of the metal substrate. This method is simple to manufacture, inexpensive, and the coating exhibits multiple excellent properties, including high impedance, high toughness, and hydrophobicity, demonstrating outstanding durability and promising application prospects in marine corrosion protection.

[0038] (1) This invention utilizes the excellent mechanical properties of nanofibers, adding them to resins to effectively improve the defects of resins as brittle materials, significantly enhance the mechanical strength of the resins, and make them more effective in protecting metal matrices. The nanofiber layer can seal the micropores generated during the coating process, cut off the transmission channels of corrosive media, and further enhance the protective performance of the material. In addition, the addition of nanofibers has good compatibility with organic resins and will not introduce new pores and interface defects to the organic resins due to dispersibility issues, thus achieving a better synergistic effect between the two.

[0039] (2) Nanofiber materials have strong modification capabilities. In this invention, sufficient modified particles are doped into the fiber material, enabling the nanofiber membrane to possess properties different from the original fiber membrane, such as conductivity, strong mechanical properties, and hydrophobicity. This can help resist the erosion of water molecules and further improve the protective performance of the resin coating. As a material to increase the toughness of the resin, a high molecular polymer containing multifunctional groups can be selected, which has good compatibility with the resin.

[0040] (3) This invention utilizes aliphatic modifiers and silane coupling agents to modify natural clay. The modified powder exhibits superhydrophobic properties. When combined with the original nanofibers, both its hydrophobicity and mechanical properties are simultaneously improved, and the nanofibers doped with modified natural clay particles retain their original fiber structure. Therefore, the nanofiber composite coating doped with hydrophobic particles of this invention possesses multiple properties, including toughening, hydrophobicity, and corrosion resistance.

[0041] (4) Compared with other common resin coatings, the present invention, after curing into a film, possesses excellent resistance to water and salt water penetration. The process is simple, the cost is low, and it exhibits superior anti-corrosion effects and strong protective capabilities. The organic coating of the present invention can be used in easily corroded metal substrates, chemical equipment, and major industrial metal equipment as a corrosion-resistant protective film material. Examples include steel piles, oil pipelines, chemical equipment, and metal equipment on ships or offshore platforms. Attached Figure Description

[0042] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0043] Figure 1 This is a SEM image of the organic coating provided in Comparative Example 1 of the present invention.

[0044] In the figure, (a) is a graph with a scale bar of 5 μm; (b) is a graph with a scale bar of 2 μm.

[0045] Figure 2 This is a SEM image of the organic coating provided in Comparative Example 2 of the present invention.

[0046] (a) is a graph with a scale bar of 10 μm; (b) is a graph with a scale bar of 1 μm.

[0047] Figure 3 This is a SEM image of the organic coating provided in Embodiment 1 of the present invention.

[0048] (a) is a graph with a scale bar of 100 μm; (b) is a graph with a scale bar of 10 μm.

[0049] Figure 4 This is a TEM image of the organic coating provided in Comparative Example 1 of the present invention.

[0050] In the figure, (a) is a graph with a scale bar of 2 μm; (b) is a graph with a scale bar of 500 nm.

[0051] Figure 5 This is a TEM image of the organic coating provided in Comparative Example 2 of the present invention.

[0052] In the figure, (a) is a graph with a scale bar of 2 μm; (b) is a graph with a scale bar of 200 nm.

[0053] Figure 6 This is a TEM image of the organic coating provided in Embodiment 1 of the present invention.

[0054] (a) is a graph with a scale bar of 5 μm; (b) is a graph with a scale bar of 1 μm.

[0055] Figure 7 This is a contact angle diagram of the organic coating provided in Comparative Example 1 of the present invention.

[0056] Figure 8 This is a contact angle diagram of the organic coating provided in Comparative Example 2 of the present invention.

[0057] Figure 9 This is a contact angle diagram of the organic coating provided in Embodiment 1 of the present invention.

[0058] Figure 10 This is a laser confocal image of the organic coating provided in Comparative Example 1 of the present invention.

[0059] Figure 11 This is a laser confocal image of the organic coating provided in Comparative Example 2 of the present invention.

[0060] Figure 12 This is a laser confocal image of the organic coating provided in Embodiment 1 of the present invention.

[0061] Figure 13 The Nyquist plots are for the organic coatings initially immersed in the organic coatings provided in Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0062] Among them, FC-0g is Comparative Example 1, FC-2g is Comparative Example 2, and FC-5g is Example 1;

[0063] (a) The x-axis ranges from 0.0 to 8.0 × 10⁻⁶. 10 Zre / (Ω·cm 2 The vertical axis ranges from 0.0 to 8.0 × 10⁻⁶. 10 -Zim / (Ω·cm 2 (a) is a graph with the x-axis ranging from 0 to 3 × 10⁻⁶. 9 Zre / (Ω·cm 2 The vertical axis ranges from 0 to 3 × 10⁻⁶. 9 -Zim / (Ω·cm 2 (The image is missing.)

[0064] Figure 14 The Nyquist plots are of the organic coatings provided in Embodiment 1, Comparative Example 1, and Comparative Example 2 of this invention after immersion for 7 days.

[0065] Among them, FC-0 is Comparative Example 1, FC-2 is Comparative Example 2, and FC-5 is Example 1;

[0066] (a) The x-axis ranges from 0.00 to 7.50 × 10⁻⁶. 6 Zre / (Ω·cm 2 The vertical axis ranges from 0.00 to 7.50 × 10⁻⁶. 6 -Zim / (Ω·cm 2 (a) is a graph with the x-axis ranging from 0.0 to 1.2 × 10⁻⁶. 6 Zre / (Ω·cm 2 The vertical axis ranges from 0.0 to 1.2 × 10⁻⁶. 6 -Zim / (Ω·cm 2 (The image is missing.)

[0067] Figure 15 The Nyquist plots are of the organic coatings provided in Embodiment 1, Comparative Example 1, and Comparative Example 2 of this invention after immersion for 15 days.

[0068] Among them, FC-0 is Comparative Example 1, FC-2 is Comparative Example 2, and FC-5 is Example 1;

[0069] (a) represents the x-axis value range of 0-8×10. 5 Zre / (Ω·cm 2 The vertical axis ranges from 0 to 8 × 10⁻⁶. 5 -Zim / (Ω·cm 2 (a) is a graph with the x-axis ranging from 0 to 5 × 10⁻⁶. 4 Zre / (Ω·cm 2 The vertical axis ranges from 0 to 5 × 10⁻⁵. 4 -Zim / (Ω·cm 2 (The image is missing.) Detailed Implementation

[0070] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0071] The present invention will now be described in detail with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0072] To address the existing problems, this invention provides a nanofiber-toughened organic coating doped with hydrophobic particles. The organic coating comprises a nanofiber layer and a resin layer. The nanofiber layer comprises nanofibers and modified hydrophobic particles. The resin layer comprises an organic resin and a curing agent. The resin layer is coated on a substrate, and the nanofiber layer is formed on the resin layer. The modified hydrophobic particles are doped into the nanofibers.

[0073] In a preferred embodiment of the present invention, the mass ratio of the modified hydrophobic particles to the nanofibers is 1:1-3 (e.g., 1:1, 1:1.4, 1:1.8, 1:2, 1:2.6, 1:2.8 or 1:3).

[0074] In a preferred embodiment of the present invention, the nanofibers account for ≥5% of the total mass percentage of the organic coating.

[0075] The thickness of the nanofiber membrane is controlled by the electrospinning time, thereby altering the quality of the nanofibers within the entire organic coating.

[0076] In a preferred embodiment of the present invention, the nanofibers are polyvinylidene fluoride with a diameter of 300-500 nm;

[0077] The modified hydrophobic particles are hydrophobic particles treated with a modifier;

[0078] The organic resin is epoxy resin, polyurethane resin, or fluorocarbon resin;

[0079] The curing agent is an epoxy resin curing agent, a polyurethane resin curing agent, or a fluorocarbon resin curing agent.

[0080] The substrate is a metal substrate.

[0081] In a preferred embodiment of the present invention, the weight ratio of the organic resin to the curing agent is 1-2:1 (e.g., 1:1, 1.25:1, 1.4:1, 1.6:1, 1.8:1 or 2:1).

[0082] The hydrophobic particles are natural clay particles with a particle size of 5-30 μm, and the natural clay particles are sepiolite particles or kaolin particles; the modifier is an aliphatic modifier or a silane coupling agent modifier.

[0083] In this invention, natural clay sepiolite or kaolin is selected, both of which are abundant in nature and possess high theoretical specific surface area, high porosity, and surface activity. These properties endow them with excellent adsorption performance for organic or inorganic ions, making it easy to functionalize the surface of clay particles. In addition, natural clay has high chemical and mechanical stability.

[0084] In a preferred embodiment of the present invention, the mass ratio of the natural clay particles to the aliphatic modifier is 1:0.5-1 (e.g., 1:0.5, 1:0.7, 1:0.8 or 1:1); the mass ratio of the natural clay particles to the silane coupling agent modifier is 1:0.05-0.2 (e.g., 1:0.05, 1:0.08, 1:0.1, 1:0.16 or 1:0.2).

[0085] In a preferred embodiment of the present invention, the substance is myristic acid, cinnamic acid, or stearic acid;

[0086] The silane coupling agent modifier is hexadecyltrimethoxysilane, octadecyltrimethoxysilane, or 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0087] Among them, aliphatic modifiers and silane coupling agents can both modify natural clay particles from hydrophilic to superhydrophobic.

[0088] This invention provides a method for preparing the aforementioned nanofiber-toughened organic coating, comprising the following steps:

[0089] Step 1: Preparation of modified hydrophobic particles:

[0090] Hydrophobic particles are dissolved in an ethanol solution, stirred evenly, and then a modifier is added. The mixture is heated to 40-50℃ (e.g., 40℃, 44℃, 45℃, 48℃, 50℃) and stirred for 10-14h (e.g., 10h, 12h, or 14h). Then it is stirred at room temperature for 5-7h (e.g., 5h, 6h, or 7h), washed, dried, and sieved to obtain modified hydrophobic particles.

[0091] Step 2: Preparation of nanofiber spinning solution:

[0092] Under conditions of temperature of 23-26℃ (e.g., 23℃, 24℃, 25℃ or 26℃) and humidity of 35%-50% (e.g., 35%, 40%, 45% or 50%), nanofibers are dissolved in an organic solvent to obtain a spinning solution; the modified hydrophobic particles obtained in step one are added to the spinning solution and stirred for 22-26 hours (e.g., 22 hours, 23 hours, 24 hours, 25 hours or 26 hours) to obtain a nanofiber spinning solution;

[0093] Step 3: Preparation of the resin-coated metal substrate:

[0094] Mix the organic resin with the curing agent and coat it evenly on the surface of the metal substrate. The coating thickness is 30-50 μm (e.g., 30 μm, 40 μm or 50 μm). Then place it in an oven at 50-70°C (e.g., 50°C, 60°C or 70°C) and dry for 15-25 min (e.g., 15 min, 20 min or 25 min) until the organic resin reaches a surface dry state.

[0095] Step 4: Preparation of toughened organic coating doped with superhydrophobic particles:

[0096] The nanofiber spinning solution obtained in step two is drawn into a syringe, and the syringe is fixed on an electrostatic coaxial spinning machine. The needle is connected to the positive and negative power supply. An aluminum foil is placed over the collector, and the resin-coated metal substrate obtained in step three is fixed on the aluminum foil. Electrospinning is performed at a temperature of 20-28°C (e.g., 20°C, 24°C, 25°C, 26°C, or 28°C) and a humidity of 20%-40% (e.g., 20%, 25%, 30%, 35%, or 40%) to obtain the nanofiber spinning solution.

[0097] Nanofiber materials, as a novel type of membrane material, are composed of nanofibers and possess a high specific surface area and extremely high porosity. However, due to their poor adhesion, they cannot be used alone as an anti-corrosion coating on metal substrates. Therefore, combining nanofiber materials with resins allows for better adhesion to metal substrates. This not only provides excellent toughening but also seals pores, compensating for the resin's inherent defects and cutting off the transmission channels of corrosive media, further enhancing the coating's protective performance. This achieves a synergistic effect between the nanofiber material and the resin.

[0098] In a preferred embodiment of the present invention, in step one, the mass ratio of hydrophobic particles to modifier is 1:0.05-1 (e.g., 1:0.05, 1:0.08, 1:0.1, 1:0.16, 1:0.2, 1:0.5, 1:0.7, 1:0.8 or 1:1); the mass ratio of hydrophobic particles to ethanol solution is 3-12g:20-80mL (e.g., 3g:20mL, 5g:60mL, 8g:70mL or 12g:80mL); the powder is washed three times by ethanol filtration, and then dried in an oven at 60-80℃ (60℃, 70℃ or 80℃) for 24 hours.

[0099] Step two, the organic solvent is N,N-methylformamide; the mass ratio of nanofibers to the volume ratio of organic solvent is 3-9g:20-60mL (e.g., 3g:20mL, 5g:40mL, 7g:50mL or 9g:60mL); the mass ratio of modified hydrophobic particles to nanofibers is 1:1-3 (e.g., 1:1, 1:1.4, 1:1.8, 1:2, 1:2.6, 1:2.8 or 1:3);

[0100] Step 3: The mass ratio of organic resin to curing agent is 1-2:1 (e.g., 1:1, 1.25:1, 1.4:1, 1.6:1, 1.8:1 or 2:1).

[0101] Step four: The spinning voltage is 20-25kV (e.g., 20kV, 21kV, 22kV, 23kV, 24kV or 25kV), the push speed of the injection pump is 0.05-0.1mm / min (e.g., 0.05mm / min, 0.06mm / min, 0.07mm / min, 0.08mm / min, 0.09mm / min or 0.1mm / min), and the spinning time is 1-8h (e.g., 1h, 2h, 3h, 4h, 5h, 6h, 7h or 8h).

[0102] This invention provides an application of the aforementioned nanofiber toughened organic coating in metal corrosion protection.

[0103] The present invention provides a detailed description of a nanofiber toughened organic coating doped with hydrophobic particles and its preparation method through specific embodiments.

[0104] Raw materials used in the embodiments of this invention:

[0105] The diameter of polyvinylidene fluoride is 300–500 nm;

[0106] The hydrophobic particles (sepiolite particles or kaolin particles) have a particle size of 5–30 μm.

[0107] Example 1

[0108] This embodiment provides a method for preparing a nanofiber-toughened organic coating doped with hydrophobic particles, comprising the following steps:

[0109] Step 1: Preparation of modified hydrophobic particles:

[0110] Weigh 5g of kaolin granules, dissolve them in 60mL of ethanol solution and stir. After stirring evenly, add 2.5g of myristic acid and heat the mixture to 45℃. Stir for 12h and then stir at room temperature for 6h. Filter and wash three times with ethanol. Place the obtained powder in a 60℃ oven for 24h, dry and sieve to obtain modified hydrophobic granules.

[0111] Step 2: Preparation of nanofiber spinning solution:

[0112] Under conditions of 25℃ and 50% humidity, 7g of polyvinylidene fluoride was weighed and dissolved in 50mL of N,N-methylformamide solvent to obtain a spinning solution; 5g of the modified hydrophobic particles obtained in step one were added to the spinning solution and stirred for 24h to obtain a nanofiber spinning solution.

[0113] Step 3: Preparation of the resin-coated metal substrate:

[0114] Epoxy resin and epoxy resin curing agent are mixed in a weight ratio of 1:0.8 and coated evenly on the surface of Q235 carbon steel substrate with a glass rod. The coating thickness is 50μm and the coating is applied once. Then, it is placed in an oven at 60℃ and dried for 20 minutes until the resin reaches a surface dry state.

[0115] Step 4: Preparation of toughened organic coating doped with superhydrophobic particles:

[0116] The nanofiber spinning solution obtained in step two is drawn into a syringe, the syringe is fixed on an electrostatic coaxial spinning machine, and the needle is connected to the positive and negative power supply; an aluminum foil is placed on the collector, and the resin-coated metal substrate obtained in step three is fixed on the aluminum foil.

[0117] The spinning voltage was adjusted to 20 kV, and the push speed of the injection pump was 0.06 mm / min. Electrospinning was carried out at 25℃ and 40% humidity for 4 hours to obtain a toughened organic coating doped with superhydrophobic particles (the mass content of nanofibers in the organic coating was 5%).

[0118] Example 2

[0119] This embodiment provides a method for preparing a nanofiber-toughened organic coating doped with hydrophobic particles. The only difference from Embodiment 1 is that the Q235 carbon steel metal substrate is replaced with a titanium alloy, while the other steps and parameters are the same as in Embodiment 1.

[0120] Example 3

[0121] This embodiment provides a method for preparing a nanofiber-toughened organic coating doped with hydrophobic particles. The only difference from Example 1 is that the kaolin particles are replaced with sepiolite particles, while the other steps and parameters are the same as in Example 1.

[0122] Example 4

[0123] This embodiment provides a method for preparing a nanofiber-toughened organic coating doped with hydrophobic particles. The only difference from Example 1 is that the myristic acid modifier is replaced with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (i.e., 5g of kaolin particles and 1g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane are added). The other steps and parameters are the same as in Example 1.

[0124] Example 5

[0125] This embodiment provides a method for preparing a nanofiber-toughened organic coating doped with hydrophobic particles. The only difference from Example 1 is that the spinning time in step four is 8 hours; all other steps and parameters are the same as in Example 1. In this embodiment, the nanofiber content in the organic coating is 10% by mass.

[0126] Comparative Example 1

[0127] This comparative example provides a method for preparing a nanofiber toughened organic coating doped with hydrophobic particles. The only difference from Example 1 is that this comparative example does not involve the preparation of modified hydrophobic particles, and no modified hydrophobic particles are added to the spinning solution in step two. Other steps and parameters are the same as in Example 1.

[0128] Comparative Example 2

[0129] This comparative example provides a method for preparing a nanofiber-toughened organic coating doped with hydrophobic particles. The only difference from Example 1 is that the amount of modified hydrophobic particles added in step two of this comparative example is different. The amount of modified hydrophobic particles added in this comparative example is 2g. The other steps and parameters are the same as in Example 1.

[0130] Comparative Example 3

[0131] This comparative example provides a method for preparing a nanofiber toughened organic coating doped with hydrophobic particles. The only difference from Example 1 is that this comparative example lacks step three, which is to directly perform electrospinning on a Q235 carbon steel metal substrate to obtain an electrospun film doped with superhydrophobic particles. The other steps and parameters are the same as in Example 1.

[0132] Comparative Example 4

[0133] This comparative example provides a method for preparing a nanofiber-toughened organic coating doped with hydrophobic particles. The only difference from Example 1 is that in step four of this comparative example, the electrospinning voltage is set to 10kV. The other steps and parameters are the same as in Example 1.

[0134] Application examples

[0135] The performance of the nanofiber-reinforced organic coatings prepared in Example 1, Comparative Example 1, and Comparative Example 2 was tested.

[0136] 1) Scanning electron microscope (SEM) image:

[0137] Each sample was sputter-coated with gold, and the surface was observed under a scanning electron microscope. The results are shown in the figure. Figure 1-3 .in Figure 1 As a comparative example 1 (the amount of modified hydrophobic particles added is 0g), its nanofibers are relatively uniformly distributed, and the diameter distribution of each nanofiber is also relatively uniform. The microstructure is ideal and relatively smooth, but there is no micro-nano structure. Figure 2 Comparative Example 2 (2g of modified hydrophobic particles added) clearly shows a micro-nano layered structure on the entire surface, with the particles clustered together and the fibers evenly distributed above the kaolin particles, exhibiting a certain degree of roughness. Figure 3 Example 1 (modified hydrophobic particles added in an amount of 5g) is mainly composed of modified kaolin powder particles with less fiber distribution. The overall micro-nano layered structure is more obvious, and no adverse phenomena such as agglomeration were found.

[0138] 2) Transmission electron microscopy (TEM) image:

[0139] The sample was placed under a transmission electron microscope to observe its internal structure. The results are shown in [Figure number missing]. Figures 4-6 .Depend on Figures 4-6 It can be seen that the fibers are uniformly distributed. As the amount of modified kaolin particles added increases, the number of particles on the fibers increases, and the micro-nano layered structure becomes more and more intuitive.

[0140] 3) Roughness and hydrophobicity angle test:

[0141] Combined with contact angle diagram ( Figures 7-9 ) and laser confocal image ( Figures 10-12It was found that as the amount of modified kaolin particles added increased, the surface roughness of the composite coating increased accordingly, and the hydrophobic angle also increased from the initial 53° to 98° and 133°. This caused the original coating to change from hydrophilic to hydrophobic, which was entirely due to the micro-nano layered structure inside the composite coating.

[0142] 4) Electrochemical impedance spectroscopy:

[0143] From Nyquist diagram ( Figures 13-15 It can be seen that the anti-corrosion performance of the composite coating increases with the increase of modified kaolin particles. From the initial soaking stage to 15 days after soaking, the impedance value of the coating sample with an addition of 5g was the highest. This is because the addition of modified kaolin improves the hydrophobicity of the coating, which can better resist the corrosion of water molecules on the metal, and the addition of nanoparticles improves the toughness of polyvinylidene fluoride fibers, thus making its anti-corrosion performance even better.

[0144] 5) The hydrophobic angle, roughness, impedance and other performance data of the organic coatings prepared in Examples 1-5 and Comparative Examples 1-4 were measured respectively, and the results are shown in Table 1 below.

[0145] Table 1 Performance data of organic coatings prepared in the examples and comparative examples

[0146]

[0147]

[0148] As can be seen from Table 1, the addition of superhydrophobic particles can improve the wettability of the coating by increasing the roughness of the coating and reducing the surface energy of the coating. The contact area between the coating and water molecules is greatly reduced, and the corrosive media dissolved in the water molecules are not easy to penetrate the coating and penetrate into the surface of the metal substrate, thereby significantly reducing the rate of corrosion. Thus, the nanofibers doped with hydrophobic particles have the effect of strengthening and toughening the coating.

[0149] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A nanofiber toughened organic coating doped with hydrophobic particles, characterized in that, The organic coating layer comprises a nanofiber layer and a resin layer; the nanofiber layer comprises nanofibers and modified hydrophobic particles; the resin layer comprises an organic resin and a curing agent; the resin layer is coated on a substrate, and the nanofiber layer is formed on the resin layer by electrospinning; the modified hydrophobic particles are doped in the nanofibers; the mass ratio of the modified hydrophobic particles to the nanofibers is 1:1-3; The nanofibers are polyvinylidene fluoride, and the diameter is 300-500 nm; The modified hydrophobic particles are hydrophobic particles treated by a modifier; the hydrophobic particles are natural clay particles, the particle size of the natural clay particles is 5-30 μm, and the natural clay particles are sepiolite particles or kaolin particles; the modifier is an aliphatic modifier or a silane coupling agent modifier; the aliphatic modifier is myristic acid, cinnamic acid or stearic acid; and the silane coupling agent modifier is hexadecyl trimethoxysilane, octadecyl trimethoxysilane or 1H, 1H, 2H, 2H-perfluorodecyl triethoxysilane; The substrate is a metal substrate; The temperature during electrospinning is 20-28 ℃, the humidity is 20%-40%, the spinning voltage is 20-25 kV, the pushing speed of the push pump is 0.05-0.1 mm / min, and the spinning time is 1-8 h.

2. The nanofiber toughened organic coating of claim 1, wherein, The mass percentage of the nanofibers in the entire organic coating layer is ≥5% by mass percentage.

3. The nanofiber toughened organic coating of claim 1, wherein, The organic resin is an epoxy resin, a polyurethane resin or a fluorocarbon resin; The curing agent is an epoxy resin curing agent, a polyurethane resin curing agent or a fluorocarbon resin curing agent.

4. The nanofiber toughened organic coating of claim 3, wherein, The weight ratio of the organic resin to the curing agent is 1-2:

1.

5. The nanofiber toughened organic coating of claim 4, wherein, The mass ratio of the natural clay particles to the aliphatic modifier is 1:0.5-1, and the mass ratio of the natural clay particles to the silane coupling agent modifier is 1:0.05-0.

2.

6. The method of preparing nanofiber toughened organic coatings according to any one of claims 1-5, wherein, Comprise the following steps: Step one, preparation of modified hydrophobic particles: Dissolve the hydrophobic particles in an ethanol solution, uniformly stir, then add the modifier, stir after warming, and then wash, dry, sieve, and obtain the modified hydrophobic particles; Step two, preparation of nanofiber spinning solution: Dissolve the nanofibers in an organic solvent to obtain a spinning solution; add the modified hydrophobic particles obtained in step one to the spinning solution, stir, and obtain the nanofiber spinning solution; Step three, preparation of a resin-coated metal substrate: Mix the organic resin and the curing agent, uniformly coat on the surface of the metal substrate, dry, and make the organic resin reach the surface dry state, and obtain the resin-coated metal substrate; Step four, preparation of a toughened organic coating layer doped with super-hydrophobic particles: Extract the nanofiber spinning solution obtained in step two into a syringe, fix the syringe on an electrostatic coaxial spinning machine, connect the needle to the positive and negative power supply, cover an aluminum foil paper on the collector, fix the resin-coated metal substrate obtained in step three on the aluminum foil paper, and perform electrospinning.

7. The preparation method of claim 6, wherein Step one, the mass ratio of the hydrophobic particles to the modifier is 1:0.05-1, and the mass ratio of the hydrophobic particles to the volume of the ethanol solution is 3-12 g:20-80 mL. After adding the modifier, first heat to 40-50℃, reach the target temperature after stirring 10-14 h, then stirring at room temperature for 5-7 h, then use ethanol to filter and wash three times, put the powder obtained in the oven at 60-80℃ to dry for 24 h; In step two, the organic solvent is N,N-methyl formamide; the mass of the nanofiber to the volume of the organic solvent is 3-9 g:20-60 mL; the mass ratio of the modified hydrophobic particles to the nanofiber is 1:1-3; The temperature of step two is 23-26℃, and the humidity is 35%-50%; the stirring time of the modified hydrophobic particles added into the spinning solution is 22-26 h; In step three, the mass ratio of the organic resin to the curing agent is 1-2:1; The thickness of the coating on the surface of the metal matrix is 30-50 mm; the drying temperature is 50-70℃, and the drying time is 15-25 min; In step four, the temperature during electrospinning is 20-28℃, the humidity is 20%-40%, the spinning voltage is 20-25 kV, the pushing speed of the push pump is 0.05-0.1 mm / min, and the spinning time is 1-8 h.

8. The application of the nanofiber toughened organic coating in metal corrosion prevention according to any one of claims 1-5.

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