Low-surface-energy antifouling coating with degradability as well as preparation method and application of low-surface-energy antifouling coating

Abstract

The invention relates to a low-surface-energy antifouling coating with degradability as well as a preparation method and application thereof, and the preparation method comprises the following steps: mixing bis (3-aminopropyl) terminated polydimethylsiloxane and 4-cyclohexene-1, 2-dicarboxylic acid diglycidyl ester, and curing to obtain the low-surface-energy antifouling coating. Epoxy containing ester group fragments and low-surface-energy siloxane with amino groups are polymerized, ester groups are grafted to side chains of siloxane polymers through ring-opening reaction of amino and epoxy, and the degradability is further provided for the antifouling coating.

Description

Technical Field

[0001] The present invention relates to the technical field of marine antifouling coatings, and in particular to a low surface energy antifouling coating with degradable properties, and a preparation method and application thereof. Background Art

[0002] Marine biofouling is the undesirable accumulation of marine microorganisms, plants, and animals on the surface of underwater structures submerged in seawater, which causes great harm to marine ship facilities and marine resources. Among the many anti-fouling strategies, the application of marine anti-fouling coatings is the simplest, most economical, and most effective anti-fouling means. However, traditional anti-fouling coatings usually contain a large amount of anti-fouling agents. When anti-fouling agents are released into the marine environment, they kill fouling organisms while seriously harming the marine ecosystem, causing secondary pollution.

[0003] Low surface energy antifouling coating is a marine antifouling coating that does not release antifouling agents. It usually uses silicone or organic fluoride polymers as a matrix and has the advantages of stable structure and non-hydrolysis. Polydimethylsiloxane (PDMS) coating is widely used as an environmentally friendly antifouling coating due to its significant characteristics such as low surface energy, low Young's modulus and cost-effectiveness.

[0004] Degradable antifouling coatings are a type of antifouling material with degradable ester groups. Their degradability comes from the ester groups in the side groups. When washed by water, the chains are broken to form a self-renewing surface, which improves the antifouling performance. Therefore, how to combine low surface energy antifouling with degradable antifouling has become a problem that needs to be solved urgently. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a low surface energy antifouling coating with degradable properties, and a preparation method and application thereof. In the present invention, an epoxy containing an ester group fragment is polymerized with a low surface energy siloxane with an amino group to achieve double antifouling, and epoxy groups are introduced to improve the mechanical properties of the coating. While enhancing the antifouling performance, this combination method can also avoid the potential pollution of the polymer material to the marine environment.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a low surface energy antifouling coating with biodegradable properties, characterized in that the structure of the low surface energy antifouling coating comprises an amino group of a bis-3-aminopropyl terminated polydimethylsiloxane connected to an epoxy group of 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester.

[0008] Preferably, the connecting chemical bond comprises an ester bond.

[0009] In a second aspect, the present invention provides a method for preparing a low surface energy antifouling coating with degradable properties according to the first aspect, the preparation method comprising:

[0010] The invention is prepared by mixing bis(3-aminopropyl)-terminated polydimethylsiloxane and 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester, and curing the mixture.

[0011] In the present invention, the method used is a one-pot method, through the polymerization reaction of NH2-PDMS and 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester, the epoxy group is ring-opened, and the ester group is grafted onto the low surface energy siloxane side chain. The specific structure is as follows Figure 1 Its degradability comes from the ester group in the side group, which is washed by water flow and breaks the chain, forming a self-renewing surface and improving the antifouling performance. Therefore, combining low surface energy antifouling with degradable antifouling can effectively make up for their respective deficiencies, thereby enhancing the overall antifouling performance of the antifouling coating.

[0012] Preferably, the molar ratio of the amino group of the bis-3-aminopropyl terminated polydimethylsiloxane to the epoxy group of 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester is 1:(1-5), wherein (1-5) may be, for example, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5.

[0013] In the present invention, within the above molar ratio range, 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester and bis-3-aminopropyl terminated polydimethylsiloxane are completely connected, which significantly improves the overall antifouling performance of the antifouling coating.

[0014] Preferably, the molecular weight of the bis-3-aminopropyl terminated polydimethylsiloxane is 2500-3000, for example, 2000, 2050, 2100, 2150, 2200, 2250, 2300, 2350, 2400, 2450 or 2500.

[0015] Preferably, the preparation method further comprises adding a solvent to the mixed raw materials for stirring, and condensing and refluxing in an oil bath.

[0016] Preferably, the solvent comprises any one of tetrahydrofuran, ethyl acetate or acetone, or a combination of at least two thereof.

[0017] Preferably, the stirring time is 20-40 min, and the rotation speed is 100-500 rpm. The 20-40 min may be, for example, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, 32 min, 34 min, 36 min, 38 min or 40 min, etc. The 100-500 rpm may be, for example, 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm or 500 rpm, etc.

[0018] Preferably, the temperature of the oil bath is 75-85°C, for example, it may be 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C or 85°C, etc.

[0019] Preferably, the condensation reflux time is 20-24 hours, for example, it can be 20 hours, 21 hours, 22 hours, 23 hours or 24 hours.

[0020] Preferably, the curing time is 3-7 days, for example, 3 days, 4 days, 5 days, 6 days or 7 days.

[0021] Preferably, the curing temperature is 20-30°C, for example, it can be 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C.

[0022] Preferably, the preparation method further comprises immersing the cured coating in silicone oil.

[0023] In the present invention, the cured coating is immersed in silicone oil to form an ultra-slip antifouling surface, thereby obtaining a smooth and relatively new coating surface, which will not produce polymer pollution to the ocean, and ultimately achieve an excellent marine antifouling effect.

[0024] Preferably, the silicone oil includes any one of methyl silicone oil, ethyl silicone oil, phenyl silicone oil or fluorine-containing silicone oil, or a combination of at least two thereof.

[0025] Preferably, the viscosity of the silicone oil is 5-100 mPa·s, for example, it may be 5 mPa·s, 10 mPa·s, 20 mPa·s, 40 mPa·s, 60 mPa·s, 80 mPa·s or 100 mPa·s.

[0026] Preferably, the soaking time is 3-7 days, for example, 3 days, 4 days, 5 days, 6 days or 7 days, etc.

[0027] In order to explore the degradability of the coating, an immersion experiment is conducted in the present invention. The steps of the immersion experiment include immersing the coating in artificial seawater, then drying the residual moisture on the surface, and re-weighing the mass to determine the degradation performance of the coating.

[0028] Preferably, the coating is immersed in artificial seawater for 30-120 days, for example, 30 days, 40 days, 60 days, 80 days, 100 days or 120 days.

[0029] Preferably, the mass ratio of the coating mass to the artificial seawater is 1:(100-200). The (100-200) may be, for example, 100, 120, 140, 160, 180 or 200.

[0030] Preferably, the temperature of drying the surface moisture of the coating is 55-65° C. The 55-65° C. may be, for example, 55° C., 56° C., 57° C., 58° C., 59° C., 60° C., 61° C., 62° C., 63° C., 64° C. or 65° C.

[0031] In a third aspect, the present invention provides a use of the low surface energy antifouling coating with degradable properties as described in the first aspect in the treatment of marine biofouling.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] (1) The present invention polymerizes an epoxy containing an ester group fragment and a low surface energy siloxane with an amino group, and utilizes the ring-opening reaction between the amino group and the epoxy group to graft the ester group onto the side chain of the siloxane polymer, thereby achieving the synergy of degradability and low surface energy, and further providing degradable properties for the antifouling coating.

[0034] (2) The present invention has excellent smoothness, environmental friendliness and degradability, and the ultra-smooth surface itself has anti-fouling properties. The preparation process is simple, retains the excellent smoothness of the ultra-smooth surface, and its low surface energy significantly reduces the ability of marine organisms to adhere to the surface.

[0035] (3) The coating studied can also form an ultra-slip antifouling surface by injecting silicone oil, thereby obtaining a smooth and relatively new coating surface that will not produce polymer pollution to the ocean, ultimately achieving an excellent marine antifouling effect. The addition of epoxy groups improves the mechanical properties and mechanical properties of the coating, achieving a synergistic effect of multiple antifouling effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the molecular formula of a low surface energy antifouling coating substrate with degradable properties.

[0037] Figure 2It is a scanning electron microscope schematic diagram of a low surface energy antifouling coating substrate with degradable properties, wherein Figure A is the coating surface of Example 4, Figure B is the coating cross-section of Example 4, Figure C is the coating surface of Example 1, and Figure D is the coating cross-section of Example 1.

[0038] Figure 3 This is a schematic diagram of the infrared spectrum of the floccules obtained after being soaked in artificial seawater in Example 1.

[0039] Figure 4 Schematic diagram of the antibacterial effect of the low surface energy antifouling coating with degradable properties, wherein Figure A is the result diagram of the blank sample, Figure B is the result diagram of Example 1, Figure C is the result diagram of Example 2, Figure D is the result diagram of Example 3, Figure E is the result diagram of Example 4, Figure F is the result diagram of Example 5, Figure G is the result diagram of Example 6, Figure H is the result diagram of Comparative Example 1, Figure I is the result diagram of Comparative Example 2, and Figure J is the result diagram of Comparative Example 3. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0041] Example 1

[0042] This example prepares a low surface energy antifouling coating with degradable properties

[0043] Mix 2.5 g of bis(3-aminopropyl)-terminated polydimethylsiloxane (molecular weight 2500) and 0.15 g of 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester at a functional group molar ratio of 1:1, add 10 g of solvent tetrahydrofuran, stir for 30 min until the oily liquid is completely dissolved, at a rotation speed of 300 rpm, transfer to a flask, stir, condense and reflux in an oil bath at 80°C for 20 h, and after the reaction, transfer the thick liquid to a hard polytetrafluoroethylene mold (mold size 15*15*2 mm), and dry and solidify at 25°C for 3 days.

[0044] The cured coating was immersed in 10 g of dimethyl silicone oil with a viscosity of 100 mPa·s and allowed to swell for 3 days. After 3 days, the coating was taken out and the residual silicone oil attached to the surface was removed.

[0045] Example 2

[0046] This example prepares a low surface energy antifouling coating with degradable properties

[0047] Mix 2.5 g of bis(3-aminopropyl)-terminated polydimethylsiloxane (molecular weight 2500) and 0.45 g of 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester at a functional group molar ratio of 1:3, add 10 g of solvent tetrahydrofuran, stir for 30 min until the oily liquid is completely dissolved, at a rotation speed of 300 rpm, transfer to a flask, stir and condense under reflux in an oil bath at 80°C for 20 h, and after the reaction, transfer the thick liquid to a hard polytetrafluoroethylene mold (mold size 15*15*2 mm), and dry and cure at 25°C for 3 days.

[0048] The cured coating was immersed in 10 g of dimethyl silicone oil with a viscosity of 100 mPa·s and allowed to swell for 3 days. After 3 days, the coating was taken out and the residual silicone oil attached to the surface was removed.

[0049] Example 3

[0050] This example prepares a low surface energy antifouling coating with degradable properties

[0051] Mix 2.5 g of bis(3-aminopropyl)-terminated polydimethylsiloxane (molecular weight 2500) and 0.75 g of 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester at a functional group molar ratio of 1:5, add 10 g of solvent tetrahydrofuran, stir for 20 min until the oily liquid is completely dissolved, rotate at 500 rpm, transfer to a flask, stir and condense under reflux in an oil bath at 75 °C for 24 h, after the reaction is completed, transfer the thick liquid to a hard polytetrafluoroethylene mold (mold size is 15*15*2 mm), and dry and cure at 30 °C for 5 days.

[0052] The cured coating was immersed in 10 g of dimethyl silicone oil with a viscosity of 50 mPa·s and swelled for 7 days. After 7 days, the coating was taken out and the residual silicone oil attached to the surface was removed.

[0053] Example 4

[0054] This example prepares a low surface energy antifouling coating with degradable properties. The only difference between this example and Example 1 is that the prepared coating is not immersed in silicone oil, and the rest is the same as Example 1.

[0055] Example 5

[0056] In this example, a low surface energy antifouling coating with biodegradable properties is prepared. The only difference between this example and Example 1 is that the mass of bis-3-aminopropyl-terminated polydimethylsiloxane (molecular weight 2500) is 2.5 g, and the mass of 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester is 0.1 g, that is, the functional group molar ratio of bis-3-aminopropyl-terminated polydimethylsiloxane and 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester is 1:0.6, and the rest is consistent with Example 1.

[0057] Example 6

[0058] In this example, a low surface energy antifouling coating with biodegradable properties is prepared. The only difference between this example and Example 1 is that the mass of bis-3-aminopropyl-terminated polydimethylsiloxane (molecular weight 2500) is 2.5 g, and the mass of 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester is 1.4 g, that is, the functional group molar ratio of bis-3-aminopropyl-terminated polydimethylsiloxane and 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester is 1:7, and the rest is consistent with Example 1.

[0059] Comparative Example 1

[0060] This comparative example prepares a low surface energy antifouling coating with degradable properties. The only difference between this comparative example and Example 1 is that epoxy resin E44 is used to replace 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester, and the rest is consistent with Example 1.

[0061] Comparative Example 2

[0062] In this comparative example, a low surface energy antifouling coating with biodegradable properties is prepared. The only difference between the comparative example and Example 1 is that 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester is not added, 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester is distributed into bis-3-aminopropyl-terminated polydimethylsiloxane according to the proportion of Example 1, and 2% of diisophorone peroxide is added, and the coating is cured at 150°C for 1 hour. The rest is consistent with Example 1.

[0063] Comparative Example 3

[0064] This comparative example prepares a low surface energy antifouling coating with biodegradable properties. The only difference between it and Example 1 is that no bis (3-aminopropyl)-terminated polydimethylsiloxane is added, and the bis (3-aminopropyl)-terminated polydimethylsiloxane is distributed to 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester according to the proportion of Example 1, and 70% of the total mass of polyamide curing agent is added, and cured at 120°C for 1 hour. The rest is consistent with Example 1.

[0065] Test Example 1

[0066] This test case is used to test the degradability performance

[0067] The low surface energy antifouling coatings with degradable properties prepared in the above examples and comparative examples were immersed in 30 mL of artificial seawater, stirred in a magnetic stirrer for 90 days, the residual moisture on the surface was dried, and the mass was re-weighed to determine the degradation performance of the coatings.

[0068] Table 1

[0069]

[0070]

[0071] From the results in Table 1 above, we can see that:

[0072] The coating prepared in the embodiment and the comparative example is immersed in artificial seawater, and the mass change is recorded to analyze the degradable performance of the coating. The degradation rate of each coating is calculated, and it can be obtained that the pure PDMS coating and the pure epoxy coating have no degradation ability due to the absence of degradable groups; compared with Example 1 and Comparative Example 1, it can be obtained that epoxy E44 does not contain degradable groups, and therefore has no degradable performance; compared with Example 1 and Example 4, the coating in Example 4 is not immersed in silicone oil, and the base coating has degradable performance, but the degradation rate is slightly lower than that of Example 1 with oil. It is speculated that the silicone oil on the surface of the coating in Example 1 forms a "silicone oil ridge" and wraps a part of the artificial seawater, so the degradation rate is slightly higher; compared with Examples 1-6, the difference between these coatings is that the proportion of the two raw materials added is different, among which the ratio of the two raw materials in Examples 1-3 is not much different, the proportion of the reaction product is large, and it has a certain degradation rate. The proportion of the raw materials of other coatings is too different, and only a small part of the product has degradable performance, so it does not show degradable performance in 30 days of artificial seawater immersion.

[0073] The coatings prepared in Example 1 and Example 4 were observed by scanning electron microscopy. Figure 2 The test results are known, among which Figure 2 A is the coating surface of Example 4, Figure 2 B is the coating cross section of Example 4, Figure 2 C is the coating surface of Example 1, Figure 2 D in the middle is the cross section of the coating of Example 1. As can be seen from the figure, the coating surface is very smooth after immersion, and almost no holes can be seen. The cross section is also smooth. Compared with the oil-free cross section, almost all the holes are filled with oil, proving that the amount of silicone oil injected is sufficient to make the original rough surface smooth.

[0074] Test Example 2

[0075] Infrared spectrum characterization of floccules obtained after immersion in artificial seawater in this example

[0076] After immersion in test example 1, the coating formed flocs in artificial seawater, and infrared spectroscopy was performed on the flocs detached from the coating prepared in Example 1. The flocs produced by the self-degradation behavior of the coating prepared in Example 1 were filtered, dried, ground and pressed into tablets, and their infrared spectra were measured. The specific test results are shown in Figure 3 As shown, among them, 1739cm -1 The peak corresponds to C=O; 1266cm -1 The peak at 2300 cm corresponds to the stretching vibration of CO; -1The peak at 1468 cm is attributed to the stretching vibration of C=C; -1 The peak at 2925cm is the bending vibration of -CH3, while the peak at 2925cm -1 The peak at comes from the strong OH stretching absorption of carboxylic acid dimer, which proves that the self-degradation product of the coating should be 4-cyclohexene-1,2-dicarboxylic acid.

[0077] Example 3

[0078] The antibacterial effect of the low surface energy antifouling coating prepared in this embodiment and the comparative example is

[0079] In order to explore the antibacterial effect of the coating prepared in the above examples and comparative examples, an experiment was conducted with Pseudomonas aeruginosa as the test object. First, 100 μL of Pseudomonas aeruginosa inoculum was placed in 10 mL of Luria-Bertani (LB) broth and cultured at a constant temperature (37°C, 180 rpm) for 6 h. The bacterial solution was then centrifuged, washed with 0.9% NaCl and resuspended. The optical density (OD) value (10 8 CFU mL –1 Finally, 10 μL of bacterial solution was diluted to 10 mL (10 5 CFUmL –1 ).

[0080] Place the prepared coatings in the above bacterial solution. After incubation in a shaking incubator for 24 hours, take 100 μL of the above prepared bacterial suspension and spread it on the solid culture matrix. After incubation at 37°C for 24 hours, use the plate count method to determine the number of surviving colonies.

[0081] Table 2

[0082]

[0083]

[0084] From the above results, we can know that:

[0085] Figure 4Figures A and J in Figure 1 respectively show the pictures of the plate colonies after the blank bacterial solution and the examples and comparative examples are cultivated. By comparison, it can be seen that the pure epoxy coating has almost no antibacterial effect, and the other coatings have a certain antibacterial effect. Among them, the number of colonies in Figure B is the least, that is, the number of colonies in Example 1 is the least. Figure I shows that after the coating in Comparative Example 2 is incubated, the number of colonies is 305. Due to the low surface energy characteristics of the double 3-aminopropyl-terminated polydimethylsiloxane, the bacteria adhere to the coating less than the pure epoxy coating. Comparing Examples 1-5, it can be obtained that when the epoxy group accounts for a certain amount, since the epoxy group does not have antibacterial properties, the coating surface cannot prevent bacterial adhesion, and the number of colonies is relatively large. Through the results of Example 1 and Example 2, that is, Figure B and Figure C, it can be obtained that the ester group of the degradable coating in Examples 1 and 2 can effectively scour the coating surface under water flow scouring, inhibiting bacterial adhesion. As can be seen from the figure, the degradable low surface energy coating in Example 1 shows excellent antibacterial adhesion effect.

[0086] In summary, the present invention opens the epoxy ring through the polymerization reaction of NH2-PDMS and 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester, and grafts the ester group onto the low surface energy siloxane side chain. The degradability is derived from the ester group in the side group, which is washed by water flow in water to break the chain, forming a self-renewing surface and improving the anti-fouling performance.

[0087] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A low surface energy antifouling coating with degradable properties, characterized in that: The structure of the low surface energy antifouling coating comprises the following steps: the amino group of bis-3-aminopropyl-terminated polydimethylsiloxane is connected with the epoxy group of 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester.

2. The low surface energy antifouling coating with degradable properties according to claim 1, characterized in that: The connecting chemical bond includes an ester bond.

3. A method for preparing a low surface energy antifouling coating with degradable properties according to claim 1 or 2, characterized in that: The preparation method comprises: The invention is prepared by mixing bis(3-aminopropyl)-terminated polydimethylsiloxane and 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester, and curing the mixture.

4. The method for preparing a low surface energy antifouling coating with degradable properties according to claim 3, characterized in that: The molar ratio of the amino group of the bis-3-aminopropyl terminated polydimethylsiloxane to the epoxy group of 4-cyclohexene-1,2-dicarboxylic acid diglycidyl ester is 1:(1-5); Preferably, the molecular weight of the bis(3-aminopropyl)-terminated polydimethylsiloxane is 2500-3000.

5. The method for preparing a low surface energy antifouling coating with degradable properties according to claim 3 or 4, characterized in that: The preparation method further comprises adding a solvent to the mixed raw materials for stirring, and performing condensation and reflux in an oil bath; Preferably, the solvent comprises any one of tetrahydrofuran, ethyl acetate or acetone, or a combination of at least two thereof.

6. The method for preparing a low surface energy antifouling coating with degradable properties according to claim 5, characterized in that: The stirring time is 20-40 minutes, and the rotation speed is 100-500 rpm.

7. The method for preparing a low surface energy antifouling coating with degradable properties according to claim 5 or 6, characterized in that: The temperature of the oil bath is 75-85°C; Preferably, the condensation reflux time is 20-24h.

8. The method for preparing a low surface energy antifouling coating with degradable properties according to any one of claims 3 to 7, characterized in that: The curing time is 3-7 days; Preferably, the curing temperature is 20-30°C.

9. The method for preparing a low surface energy antifouling coating with degradable properties according to any one of claims 3 to 7, characterized in that: The preparation method further comprises immersing the cured coating in silicone oil; Preferably, the silicone oil includes any one of methyl silicone oil, ethyl silicone oil, phenyl silicone oil or fluorine-containing silicone oil, or a combination of at least two thereof; Preferably, the viscosity of the silicone oil is 5-100 mPa·s; Preferably, the soaking time is 3-7 days.

10. Use of the degradable low surface energy antifouling coating according to claim 1 or 2 in treating marine biofouling.

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