A slow-release antifouling material, its preparation method, and a marine antifouling coating

Abstract

This invention relates to a slow-release antifouling material, its preparation method, and a marine antifouling coating. The preparation method of the slow-release antifouling material includes: amylating porous silica to obtain aminated porous silica; loading a carboxylic acid-based natural antifouling agent onto the aminated porous silica to obtain aminated porous silica@antifouling agent; sealing the pores in the aminated porous silica@antifouling agent with gelatin to obtain aminated porous silica@antifouling agent@gelatin; mixing the aminated porous silica@antifouling agent@gelatin with a chitosan solution at 25–45°C for at least 0.5 hours, collecting the product, and drying it to obtain the slow-release antifouling material. This slow-release antifouling material can reduce the release rate of the antifouling agent and improve the protective effect on marine equipment.

Description

Technical Field

[0001] This invention relates to a slow-release antifouling material, its preparation method, and a marine antifouling coating, belonging to the field of marine biofouling protection. Background Technology

[0002] Microorganisms and macroscopic organisms often attach to and accumulate on marine facilities such as ships, buoys, marine pipelines, and membrane pipes, forming biofouling. This biofouling accelerates the corrosion of marine facilities or causes pipeline blockage. Antifouling coatings containing antifouling agents are an effective measure to protect marine facilities. In particular, in recent years, natural components extracted from plants and animals, such as organic acids, inorganic acids, lactones, terpenes, phenols, sterols, and indoles, have excellent antifouling properties and good environmental friendliness. Using them as antifouling agents in antifouling coatings is a green and environmentally friendly approach, thus natural product antifouling coatings are receiving increasing attention.

[0003] The effectiveness of antifouling coatings largely depends on the retention of the antifouling agent within the coating. A relatively constant and low-dose release rate of the antifouling agent is beneficial for maximizing its protective effect. However, current antifouling coatings contain natural antifouling agents that release rapidly into seawater, resulting in a short antifouling period. Therefore, there is an urgent need for a slow-release antifouling material and a marine antifouling coating. Summary of the Invention

[0004] Based on the above-mentioned situation, this invention discloses a slow-release antifouling material and its preparation method. The slow-release antifouling material obtained by this method exhibits a slow and stable release rate of the carboxylic acid-based natural antifouling agent in seawater, ensuring protective performance and extending the antifouling period. This invention also provides a marine antifouling coating comprising the above-mentioned slow-release antifouling material.

[0005] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a slow-release antifouling material, comprising the following steps performed in sequence:

[0006] S1. Aminoation modification of porous silica to obtain aminoized porous silica;

[0007] S2. Carboxylic acid-based natural antifouling agents are loaded onto aminated porous silica to obtain aminated porous silica@antifouling agent;

[0008] S3. Use gelatin to seal the pores in the aminated porous silica@antifouling agent to obtain aminated porous silica@antifouling agent@gelatin;

[0009] S4. Mix the aminated porous silica@antifouling agent@gelatin with chitosan solution at 25-45°C for at least 0.5 hours, wherein the mass ratio of aminated porous silica@antifouling agent@gelatin to chitosan is (1-3):5. Collect the product and dry it to obtain a slow-release antifouling material.

[0010] Porous silica is a representative of porous materials, and based on its pore size, it can be further divided into microporous, mesoporous, and macroporous silica. Mesoporous silica, in particular, possesses advantages such as high loading capacity, slow-release tendency, ease of surface modification, and high mechanical strength and thermal stability. It can achieve tight bonding with antifouling agents, thereby reducing the release rate and extending the antifouling period. In this invention, common mesoporous silica, such as MCM-41, SBA-15, and SBA-16 silicon-based mesoporous molecular sieves, or mixtures of various mesoporous silicas can be selected. This invention achieves tight bonding between porous silica, such as mesoporous silica, and carboxylic acid-based natural antifouling agents by amylating the surface of the porous silica, thereby improving the loading capacity and slow-release performance of the carboxylic acid-based natural antifouling agents.

[0011] In the specific implementation process, step S1, the process of amylating the porous silica includes: mixing the porous silica with the aminated silane coupling agent in a solvent, reacting at 70-90°C for at least 6 hours, such as 12 hours, and drying the solid product to obtain the aminated porous silica.

[0012] The aforementioned aminosilane coupling agent can be, for example, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane. The amount of the aminosilane coupling agent used can be 20-60% of the mass of the porous silica. The aforementioned solvent can be an organic solvent such as toluene or ethanol.

[0013] Subsequently, carboxylic acid-based natural antifouling agents are loaded onto aminated porous silica to obtain aminated porous silica@indole antifouling agent. Common loading processes can be employed. One loading process involves contacting the aminated porous silica with the carboxylic acid-based natural antifouling agent in a solvent, allowing the carboxylic acid-based natural antifouling agent to be loaded onto the aminated porous silica. After loading, the solvent is removed, and the product is washed and dried to obtain aminated porous silica@antifouling agent. Through this loading process, carboxylic acid-based natural antifouling agents, such as indoleacetic acid, can form electrostatic bonds with amino-modified silica-based mesoporous molecular sieves.

[0014] In the specific implementation process, the loading process in step S2 includes: mixing aminated porous silica with a solvent, then adding a carboxylic acid-based natural antifouling agent, and mixing at a temperature of 25-35°C for at least 1 hour.

[0015] The aforementioned carboxylic acid-based natural antifouling agents can specifically be indoleacetic acid; the solvents used can be low-boiling-point organic solvents such as acetone or ethanol that are readily soluble in water.

[0016] Studies have shown that rationally controlling the mass ratio of aminated porous silica to carboxylic acid-based natural antifouling agents is beneficial to improving the antibacterial performance of slow-release antifouling materials. In practice, the mass ratio is generally controlled at (1-2):(1-2), for example, 1:1, 1:2, or 2:1. Furthermore, within the above range, a relatively higher amount of carboxylic acid-based natural antifouling agent is more conducive to improving the antibacterial performance of slow-release antifouling materials; therefore, the mass ratio of aminated porous silica to carboxylic acid-based natural antifouling agents is generally controlled at 1:(1-2).

[0017] The purpose of step S3 is to temporarily seal the pores of the product material prepared in step S2, specifically the porous silica, to prevent the carboxylic acid-based natural antifouling agent from seeping into the chitosan during the subsequent step S4, thus affecting the sustained-release effect. Specifically, step S3 may include the following process: mixing aminated porous silica@antifouling agent with a gelatin solution at 25-35°C for at least 1 hour, wherein the mass ratio of aminated porous silica@antifouling agent to gelatin is (0.8-1.0):1; collecting the product, washing and drying it to obtain aminated porous silica@antifouling agent@gelatin;

[0018] In the specific implementation process, the process of step S3 can be as follows: put the aminated porous silica@antifouling agent into the gelatin aqueous solution, then put it in a constant temperature shaker at 25-45℃ for 5 hours, add deionized water at 4℃ and centrifuge and wash twice, filter, and dry at a low temperature such as 30℃ to obtain aminated porous silica@antifouling agent@gelatin.

[0019] Finally, the target product is synthesized. Specifically, the process involves: dispersing chitosan evenly in an acetic acid solution to obtain a chitosan solution; then adding aminated porous silica@antifouling agent@gelatin to the solution, controlling the mass ratio of chitosan to aminated porous silica@antifouling agent@gelatin to be 2:5; stirring evenly; pouring the solution into a petri dish; and drying in a vacuum drying oven at 35°C to obtain a slow-release antifouling material. Through step S4, chitosan can serve as a substrate to synergistically support the modified antifouling agent carrier, improving antibacterial performance and simultaneously blocking the pores of the molecular sieve carrier to reduce the release rate of carboxylic acid-based natural antifouling agents such as indoleacetic acid, achieving long-lasting antifouling effects.

[0020] A second aspect of the present invention provides a slow-release antifouling material, which is prepared by the preparation method described in the first aspect above.

[0021] A third aspect of this invention provides a marine antifouling coating comprising the aforementioned slow-release antifouling material. In addition to the aforementioned slow-release antifouling material, the marine antifouling coating may also contain solvents, pigments, fillers, and other components. Specific components and proportions can be selected according to actual needs, and will not be elaborated further here.

[0022] The present invention provides a sustained-release antifouling material and its preparation method. The sustained-release antifouling material is synthesized by an adsorption equilibrium solvent evaporation method. Specifically, by modifying the surface of porous silica such as silica-based mesoporous molecular sieves with amino groups, the binding with carboxylic acid-based natural antifouling agents can be enhanced, thereby increasing the drug loading and sustained-release performance. Chitosan can be used as a substrate to synergistically enhance the antifouling agent carrier, thereby improving its antibacterial performance. At the same time, chitosan can also block the pores of the molecular sieve carrier to reduce the release rate of carboxylic acid-based natural antifouling agents such as indoleacetic acid, thus achieving long-lasting antifouling effect.

[0023] The marine antifouling coating provided by this invention, because it includes the above-mentioned slow-release antifouling material, has good antifouling performance and a long antifouling period, thereby providing effective protection for marine facilities. Attached Figure Description

[0024] Figure 1 Infrared spectra of the intermediate and final products obtained in Example 1 of the present invention;

[0025] Figure 2 The XRD patterns of the intermediate and final products obtained in Example 1 of this invention are shown.

[0026] Figure 3 This is a graph showing the cumulative release of indoleacetic acid in the slow-release antifouling material prepared in Example 1 of the present invention;

[0027] Figure 4 The diagram shows the antibacterial effect of chitosan and the slow-release antifouling materials prepared in Examples 1-3. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] This embodiment provides a slow-release antifouling material, the preparation method of which is as follows:

[0031] S1. Preparation of Aminated-SBA-16: 1 g of SBA-16 and 0.6 g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (silane coupling agent KH-792) were mixed in 70 mL of toluene, heated to 80±5 °C and stirred for 12 hours, then filtered. The mixture was then placed in a vacuum drying oven at about 70 °C for about 5 hours to obtain aminated-SBA-16, which is a white powder.

[0032] S2. Preparation of Aminated-SBA-16@Indoleacetic Acid: Dissolve 1g of aminated-SBA-16 in 30mL of acetone solvent, add indoleacetic acid under heating and stirring at 30℃ for 10 hours, wherein the mass ratio of aminated-SBA-16 to indoleacetic acid is 2:1; after the reaction is completed, the solution is rotary evaporated, washed with the appropriate solvent, and placed in a vacuum drying oven at 30±1℃ for about 5 hours to obtain aminated-SBA-16@indoleacetic acid, which is a reddish-brown powder;

[0033] Preparation of S3, Aminated-SBA-16@Indoleacetic Acid@Gelatin: Take 1g of aminated-SBA-16@indoleacetic acid and place it in a gelatin solution with a concentration of 50mg / mL and a volume of 20mL (i.e., the mass ratio of gelatin to aminated-SBA-16@indoleacetic acid is 1:1). Then place it in a constant temperature shaker at 30±1℃ for about 5 hours. After that, add deionized water at 4℃ and centrifuge and wash twice. After filtration, dry at 30℃±1℃ for about 12 hours to obtain aminated-SBA-16@indoleacetic acid@gelatin.

[0034] S4. Preparation of Aminated-SBA-16@Indoleacetic Acid@Chitosan: 1 g of chitosan was added to 100 mL (1%, vol%) of acetic acid solution and dispersed evenly to obtain a 10 mg / mL chitosan solution. Aminated-SBA-16@Indoleacetic Acid@Gelatin was added to the above chitosan solution, and the mass ratio of chitosan to aminated-SBA-16@Indoleacetic Acid@Gelatin was controlled at 2:5. After stirring for about 1 hour, the mixture was poured into a petri dish and dried in a vacuum drying oven at 35±1℃ for about 12 hours to obtain an aminated-SBA-16@Indoleacetic Acid@Chitosan coating.

[0035] Example 2

[0036] This embodiment provides a slow-release antifouling material, the preparation method of which is basically the same as that of Example 1, the only difference being that the mass ratio of aminated-SBA-16 to indoleacetic acid in step S2 is 1:1.

[0037] Example 3

[0038] This embodiment provides a slow-release antifouling material, the preparation method of which is basically the same as that of Example 1, the only difference being that the mass ratio of aminated-SBA-16 to indoleacetic acid in step S2 is 1:2.

[0039] Figure 1 These are the infrared spectra of the intermediate and final products obtained in Example 1 of this invention. Figure 1 As shown, in the infrared spectrum of the product (amino-SBA-16@indoleacetic acid) from step S2, at 3400 cm⁻¹... -1 The appearance of sharp peaks on both sides is characteristic of indoleacetic acid, confirming the successful loading of porous silica SBA-16 after indoleacetic acid was aminated; in the infrared spectrum of the product (aminated-SBA-16@indoleacetic acid@chitosan) from step S4, the peak at 3400 cm⁻¹ is... -1 The appearance of the dome-shaped peaks on the left and right is due to the addition of chitosan, 1450-1600 cm⁻¹ -1 The weakening of the characteristic absorption peak of the benzene ring indirectly confirms that the amino-SBA-16@indoleacetic acid was successfully encapsulated by chitosan.

[0040] Figure 2 These are the X-ray diffraction (XRD) patterns of the intermediate and final products obtained in Example 1 of this invention. Figure 2 As shown, the product of step S2, aminated-SBA-16@indoleacetic acid, showed a diffraction peak of indoleacetic acid, indicating that the amination-treated porous silica SBA-16 was successfully loaded with indoleacetic acid. However, the product of step S4, aminated-SBA-16@indoleacetic acid@chitosan, did not have a diffraction peak of indoleacetic acid. It is speculated that the indoleacetic acid loaded in the amination-treated porous silica SBA-16 may have been blocked inside the pores by chitosan.

[0041] Assessment Example 1

[0042] Sustained-release performance evaluation: 50 mg each of amino-SBA-16@indoleacetic acid and amino-SBA-16@indoleacetic acid@chitosan from Example 2, and 50 mg of SBA-16@indoleacetic acid, were placed in 100 mL of seawater. The concentration change of indoleacetic acid in the seawater was continuously measured using a UV spectrophotometer. The results are as follows: Figure 4 As shown.

[0043] The preparation process of SBA-16@indoleacetic acid is similar to step S2 in Example 2, except that the raw material is changed from aminated-SBA-16 to SBA-16. The specific process is as follows: 1g of SBA-16 is dissolved in 30mL of acetone solvent, and indoleacetic acid is added under heating and stirring at 30°C for 10 hours. The mass ratio of SBA-16 to indoleacetic acid is 1:1. After the reaction is completed, the solution is rotary evaporated, washed with the corresponding solvent, and placed in a vacuum drying oven at 30±1°C for about 5 hours to obtain SBA-16@indoleacetic acid.

[0044] The results showed that, within a short period of time, indoleacetic acid (IAA) in both SBA-16@indoleacetic acid and aminated-SBA-16@indoleacetic acid was rapidly released from seawater: after approximately 3 days, the release rate of IAA reached over 80%; after approximately 4 days, the release rate of IAA reached 90%. Furthermore, it was noted that although both IAA components were rapidly released within a short time, the release rate of IAA in aminated-SBA-16@indoleacetic acid was slower, indicating that aminated treatment of SBA-16 can improve the binding force between IAA and SBA-16.

[0045] Compared to SBA-16@indoleacetic acid and aminated-SBA-16@indoleacetic acid, the release rate of indoleacetic acid in aminated-SBA-16@indoleacetic acid@chitosan is significantly reduced. Even when the release rate of indoleacetic acid in the former two reaches 90%, the release amount of indoleacetic acid in the aminated-SBA-16@indoleacetic acid@chitosan material is less than 20%. Furthermore, further verification shows that after approximately 40 days, the release amount of indoleacetic acid in aminated-SBA-16@indoleacetic acid@chitosan reaches 90%. This indicates that the slow-release antifouling material in this embodiment of the invention greatly extends the release time of the indoleacetic acid antifouling agent, ensuring the protective effect of the marine antifouling coating on marine facilities. This also confirms that chitosan blocks the pores of the molecular sieve carrier, allowing indoleacetic acid to be released at a relatively stable and small dose rate.

[0046] Assessment Example 2

[0047] Antibacterial performance evaluation: After preparing fresh Bacillus subtilis cultures, the bacterial cultures were grown at 37°C for 24 hours. Twelve panels (1cm × 1cm) were divided into four groups of three. Chitosan and the slow-release antifouling material from Examples 1 to 3 were coated onto each panel, with the chitosan coating serving as a negative control. 3 mL of sterile marine broth was mixed with a Bacillus subtilis bacterial culture at a concentration of approximately 10 CFU (colony-forming units) / mL and added to each well. The CFU count in all treatments was measured at 0 and 24 hours. The results are as follows: Figure 4As shown in the figure, 2:1, 1:1, and 1:2 represent the mass ratios of amino-SBA-16 and indoleacetic acid in step S2, i.e., Examples 1 to 3.

[0048] The results showed that, at the same initial concentration (approximately 10 CFU / mL), after 24 hours, coating the panel with the slow-release antifouling materials from Examples 1 to 3 increased the bacterial inactivation rate compared to pure chitosan. This indicates that the aminated-SBA-16@indoleacetic acid@chitosan prepared in different examples all have a certain antibacterial effect against Bacillus subtilis, and the aminated-SBA-16@indoleacetic acid@chitosan with a mass ratio of aminated-SBA-16 to indoleacetic acid of 1:2 has the best effect.

[0049] The results above show that the slow-release antifouling material prepared by this invention has a good effect on prolonging marine antifouling. Therefore, it can be used to solve the problem of explosive release of marine antifouling agents and has good application prospects.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a slow-release antifouling material, characterized in that, Includes the following steps: Amination modification was performed on porous silica to obtain amination-modified porous silica. A carboxylic acid-based natural antifouling agent was loaded onto aminated porous silica to obtain aminated porous silica@antifouling agent; The pores in the aminated porous silica@antifouling agent were sealed with gelatin to obtain the aminated porous silica@antifouling agent@gelatin; Aminated porous silica@antifouling agent@gelatin and chitosan solution were mixed at 25-45°C for at least 0.5 hours, wherein the mass ratio of aminated porous silica@antifouling agent@gelatin to chitosan was (1-3):

5. The product was collected and dried to obtain a slow-release antifouling material.

2. The preparation method according to claim 1, characterized in that, The porous silica is mesoporous silica.

3. The preparation method according to claim 1 or 2, characterized in that, The process of amylating porous silica includes: Porous silica and an aminosilane coupling agent are mixed in a solvent and reacted at 70–90°C for at least 6 hours. The solid product is then collected and dried to obtain amino-modified porous silica. The aminosilane coupling agent accounts for 20-60% of the mass of porous silica.

4. The preparation method according to claim 1, characterized in that, The carboxylic acid-based natural antifouling agent is indoleacetic acid.

5. The preparation method according to claim 1 or 4, characterized in that, The process of obtaining aminated porous silica@antifouling agent includes: contacting aminated porous silica with carboxylic acid natural antifouling agent in a solvent, so that the carboxylic acid natural antifouling agent is loaded onto the aminated porous silica, wherein the mass ratio of aminated porous silica to carboxylic acid natural antifouling agent is (1~2):(1~2), after loading is completed, the solvent is removed and the product is washed and dried.

6. The preparation method according to claim 5, characterized in that, The loading process includes adding a carboxylic acid-based natural antifouling agent to a mixture of aminated porous silica and a solvent, and mixing at a temperature of 25–35°C for at least 1 hour.

7. The preparation method according to claim 1, characterized in that, Gelatin is used to seal the pores in aminated porous silica@antifouling agent, including: Aminated porous silica@antifouling agent and gelatin solution are mixed at 25-35°C for at least 1 hour, wherein the mass ratio of aminated porous silica@antifouling agent to gelatin is (0.8-1.0):

1. The product is collected, washed and dried to obtain aminated porous silica@antifouling agent@gelatin.

8. A slow-release antifouling material, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.

9. A marine antifouling coating, characterized in that, Includes the slow-release antifouling material as described in claim 8.

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