A piezoelectric antifouling coating, its preparation method and application
By preparing a piezoelectric antifouling coating and combining it with acid-modified tourmaline and multi-walled carbon nanotubes with modified polyurethane, the problems of poor antibacterial performance and low mechanical strength of existing antifouling coatings were solved, achieving effective antifouling and bactericidal effects on marine organisms.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SANYA SCI & EDUCATION INNOVATION PARK WUHAN UNIV OF TECH
- Filing Date
- 2024-04-01
- Publication Date
- 2026-05-26
Smart Images
Figure CN118291007B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of marine antifouling coating technology, specifically relating to a piezoelectric antifouling coating, its preparation method, and its application. Background Technology
[0002] Biofouling is a major global problem. Various algae and large organisms in the ocean can reversibly or irreversibly adhere to the surfaces of underwater materials in the marine environment, causing significant economic losses to the marine industry. Coastal underwater structures (including bridges and docks) and marine facilities (including oilfield facilities and offshore drilling platforms) are all susceptible to marine biofouling, while the operation of large ocean-going cruise ships is also affected; biofouling on the hull can lead to hull surface deterioration, causing structural damage and reducing safety. Furthermore, biofouling indirectly accelerates global warming and exacerbates the environmental impact of biological invasions. Therefore, the research and development of marine antifouling coatings is of great significance.
[0003] Currently, hydrophobic coatings are the most widely used marine antifouling coatings. The antifouling mechanism of hydrophobic coatings involves imparting micro / nano structures to the coating surface. These micro / nano structures possess excellent self-cleaning and antifouling properties, forming a physical barrier for the surface matrix to resist biofouling and prevent biological adhesion. However, the coating itself lacks bactericidal properties, making it difficult to remove once fouling organisms have grown. Furthermore, the coating has poor mechanical properties and poor recoating ability, limiting its application range. Summary of the Invention
[0004] The purpose of this invention is to provide a piezoelectric antifouling coating, its preparation method, and its application, to solve the problems of poor antibacterial performance, low mechanical strength, and poor adhesion of existing antifouling coatings.
[0005] In a first aspect, the present invention provides a method for preparing a piezoelectric antifouling coating, comprising the following steps: mixing and dispersing an acid-modified tourmaline dispersion and a multi-walled carbon nanotube dispersion; drying the product to obtain a filler; adding the filler, epoxy resin, and additives to an organic solution for grinding; then adding a curing agent; and drying to obtain a piezoelectric layer; providing a modified polyurethane solution, wherein the modified polyurethane solution is obtained by reacting hexamethylene diisocyanate trimer with hydroxyl-terminated polybutadiene and polydimethylsiloxane; adding an initiator to the modified polyurethane solution; then coating the solution onto the surface of the piezoelectric layer; and curing and drying the solution under ultraviolet light to obtain a piezoelectric antifouling coating.
[0006] In this invention, the inventors discovered that the low surface energy and high elastic modulus of the hydrophobic and antifouling coating surface can significantly reduce the adhesion strength of contaminating organisms. Therefore, the attached organisms on the coating surface are easily removed by shear force. Furthermore, using hydroxyl-terminated polybutadiene as a soft segment, it is reacted with hexamethylene diisocyanate trimer and polydimethylsiloxane to obtain a modified polyurethane. This modified polyurethane has a low surface energy, which can significantly reduce the attachment sites for marine organisms. Simultaneously, its good elastic modulus also facilitates the removal of weakly attached organisms. When the modified polyurethane is coated with a piezoelectric coating, the composite material generates a potential difference when subjected to pressure changes caused by ocean currents from the ocean floor, thereby stimulating the generation of active oxygen and giving the composite material bactericidal properties.
[0007] It should be noted that the curing agent in this invention can be selected and added in a conventional manner according to actual use needs. For example, the curing agent can be 593 curing agent.
[0008] In some embodiments, during the preparation of the piezoelectric layer, the volume ratio of the acid-modified tourmaline dispersion to the multi-walled carbon nanotube dispersion is (1.5-2.5):1, for example, 1.5:1, 1.7:1, 2:1, 2.3:1, 2.5:1 or other values within this range; dispersion includes ultrasonic dispersion for 25-35 min, for example, 25 min, 27 min, 30 min, 33 min, 35 min or other values within this range; drying includes drying at a temperature of 60-80°C (for example, 60°C, 65°C, 70°C, 80°C or other values within this range) for 40-50 min, for example, 40 min, 42 min, 44 min, 46 min, 48 min, 50 min or other values within this range.
[0009] In this invention, the inventors discovered that acid modification of tourmaline results in a piezoelectric layer with better flexibility and mechanical properties.
[0010] In some embodiments, the preparation of the acid-modified tourmaline dispersion includes: adding tourmaline to an acid solution and subjecting it to ultrasonic oscillation to obtain an acid-modified tourmaline solution; after centrifugation, washing, and drying, the acid-modified tourmaline solution is added to an organic solution to obtain an acid-modified tourmaline dispersion; the preparation of the multi-walled carbon nanotube dispersion includes: adding multi-walled carbon nanotubes to an organic solution and subjecting it to ultrasonic oscillation to obtain a multi-walled carbon nanotube dispersion; wherein the mass ratio of tourmaline to multi-walled carbon nanotubes is (0.5-1.5):1.
[0011] It should be noted that the organic solutions used in the preparation of acid-modified tourmaline dispersion and the organic solutions used in the preparation of multi-walled carbon nanotube dispersion can be conventional organic solutions used in the field, such as dimethyl sulfoxide.
[0012] In some embodiments, during the preparation of the acid-modified tourmaline dispersion, the mass-to-volume ratio of tourmaline to the acid solution is 1:(0.5-1), for example, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, or other values within this range; the mass concentration of the acid solution is 3-7%, for example, 3%, 4%, 5%, 6%, 7%, or other values within this range; and it is selected from hydrochloric acid solution or nitric acid solution. Ultrasonic oscillation includes an oscillation time of 25-35 min, for example, 25 min, 27 min, 30 min, 33 min, 35 min, or other values within this range; the acid-modified tourmaline dispersion... The mass ratio of carbon nanotubes to organic solution is 1:(0.5-1), for example, it can be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1 or other values within this range; in the preparation of multi-walled carbon nanotube dispersion, the mass ratio of multi-walled carbon nanotubes to organic solution is 1:(0.5-1), for example, it can be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1 or other values within this range; ultrasonic oscillation includes an oscillation time of 25-35 min, for example, it can be 25 min, 27 min, 30 min, 33 min, 35 min or other values within this range.
[0013] In some embodiments, during the preparation of the piezoelectric layer, the mass ratio of filler to epoxy resin is 1:(1.5-3), for example, 1:1.5, 1:2, 1:2.5, 1:3, or other values within this range; the additives include: 0.5-1.5 parts (e.g., 0.5 parts, 0.7 parts, 1 part, 1.3 parts, 1.5 parts, or other values within this range) of defoamer; 0.5-1.5 parts (e.g., 0.5 parts, 0.7 parts, 1 part, 1.3 parts, 1.5 parts, or other values within this range) of anti-settling agent; and 0.5-1.5 parts (e.g., 0.5 parts, 0.7 parts, 1 part, 1.3 parts, 1.5 parts, or other values within this range) of leveling agent. 1.5-2.5 parts (e.g., 1.5 parts, 1.7 parts, 2 parts, 2.3 parts, 2.5 parts or other values within this range) of dispersant, the organic solvent including xylene and n-butanol, grinding is carried out in a conical mill and the grinding time is 0.5-1.5 h, e.g., 0.5 h, 0.7 h, 1 h, 1.3 h, 1.5 h or other values within this range; drying includes: drying temperature of 65-75°C, e.g., 65°C, 67°C, 70°C, 73°C, 75°C or other values within this range; drying time of 4.5-5.5 h, e.g., 4.5 h, 4.7 h, 5 h, 5.3 h, 5.5 h or other values within this range.
[0014] It should be noted that the defoamer, anti-settling agent, leveling agent, and dispersant in this invention can be conventionally selected and added according to actual usage needs. For example, the defoamer can be Silok-4010, the anti-settling agent can be organic bentonite, the leveling agent can be Silok-350, and the dispersant can be Silok-7066.
[0015] In some embodiments, the reaction of hexamethylene diisocyanate trimer with hydroxyl-terminated polybutadiene further includes the addition of pentaerythritol triacrylate to the reaction system, and the reaction method includes: mixing hexamethylene diisocyanate trimer, hydroxyl-terminated polybutadiene, and pentaerythritol triacrylate at a molar ratio of isocyanate groups to hydroxyl groups of 1:1, dissolving in an organic solvent, adding 0.1% by mass of an organic bismuth catalyst, and reacting at 65-75°C (e.g., 65°C, 67°C, 70°C, 73°C, 75°C, or other values within this range) under an inert atmosphere for 3-4 hours (e.g., 3 hours, 3.2 hours, 3.5 hours, 3.7 hours, 4 hours, or other values within this range) to obtain a reaction initiator.
[0016] In some embodiments, while the intermediate compound continues to react with polydimethylsiloxane, trimethylolpropane is added to the reaction system, and the reaction method includes: mixing the reaction initiator, polydimethylsiloxane, and trimethylolpropane at a molar ratio of isocyanate groups to hydroxyl groups of 1:1, and adding polydimethylsiloxane at a mass concentration of 2-5%, for example, 2%, 3%, 4%, 5%, or other values within this range; then dissolving it in an organic solvent, and reacting it under an inert atmosphere at 65-75°C, for example, 65°C, 67°C, 70°C, 73°C, 75°C, or other values within this range; reacting for 3-4 hours, for example, 3 hours, 3.2 hours, 3.5 hours, 3.7 hours, 4 hours, or other values within this range; and removing the organic solvent to obtain a modified polyurethane solution.
[0017] It should be noted that the organic solvent and inert gas in this invention can be conventionally selected and added according to actual usage requirements. For example, the organic solvent can be tetrahydrofuran, and the inert gas can be nitrogen or argon.
[0018] In some embodiments, before adding the initiator to the modified polyurethane solution, the addition of trimethylolpropane triacrylate is further included, wherein the mass concentration of the added trimethylolpropane triacrylate is 10-25%, for example, 10%, 15%, 20%, 25%, or other values within this range; the mass concentration of the added initiator is 0.5-1.5%, for example, 0.5%, 0.7%, 1%, 1.3%, 1.5%, or other values within this range; and the initiator is photoinitiator 1173; UV curing includes: an irradiation power of 950-1500W, for example, 950W, 1000W, 1200W, 1400W, 1500W, or other values within this range; and a wavelength of 360-37 nm. 0nm, for example, can be 360nm, 362nm, 365nm, 367nm, 370nm or other values within this range; the irradiation distance is 5-15cm, for example, can be 5cm, 7cm, 10cm, 13cm, 15cm or other values within this range; the curing time is 55-65s, for example, can be 55s, 57s, 60s, 63s, 65s or other values within this range; drying includes: drying at a temperature of 65-75℃ (for example, can be 65℃, 67℃, 70℃, 73℃, 75℃ or other values within this range) for 25-35min, for example, can be 25min, 27min, 30min, 33min, 35min or other values within this range.
[0019] In a second aspect, the present invention provides a piezoelectric antifouling coating prepared using any of the above-described preparation methods.
[0020] In a third aspect, the present invention provides the application of the above-mentioned piezoelectric antifouling coating in the protection of underwater material surfaces in marine environments.
[0021] The beneficial effects of this invention are as follows: Unlike the prior art, this invention mixes fillers prepared from acid-modified tourmaline and multi-walled carbon nanotubes with epoxy resin to obtain a piezoelectric layer with piezoelectric properties. Then, using hydroxyl-terminated polybutadiene as a soft segment, it reacts with hexamethylene diisocyanate trimer and polydimethylsiloxane to obtain a hydrophobic modified polyurethane coating. This hydrophobic modified polyurethane coating has certain adhesion, good mechanical strength, and hydrophobicity. Furthermore, the piezoelectric coating and the hydrophobic coating are crosslinked by ultraviolet light curing, so that the prepared piezoelectric antifouling coating can reduce the attachment of large marine organisms and kill marine microorganisms attached to the coating surface. Attached Figure Description
[0022] Figure 1 This is a photograph of the acid-modified tourmaline prepared in Example 1 of the present invention.
[0023] Figure 2 The infrared spectra of hydroxyl-terminated polybutadiene (HTPB), reaction initiator (HTPB-HDIT), and modified polyurethane (Si-PU) in Example 1 of this invention are shown.
[0024] Figure 3 The images show the surface morphology of the piezoelectric antifouling coating prepared in Example 1 of this invention; where (a) is a hydrophobic modified polyurethane coating (3000×), (b) is a piezoelectric coating (500×), (c) is a piezoelectric coating (1000×), and (d) is a piezoelectric coating (3000×).
[0025] Figure 4 This is a photograph of the piezoelectric antifouling coating prepared in Example 1 of the present invention coated on the surface of an iron substrate;
[0026] Figure 5 The piezoelectric voltage test results of the piezoelectric layer prepared by the present invention are shown in (A) and (B) respectively.
[0027] Figure 6 The stress-strain curves of the piezoelectric layers prepared in Examples 1, 3 and Comparative Example 3 of this invention are shown below.
[0028] Figure 7 The water contact angle test results of the hydrophobic modified polyurethane coatings prepared in Examples 1, 4 and Comparative Example 5 of this invention;
[0029] Figure 8 The tensile test results are those of the hydrophobic modified polyurethane coatings prepared in Examples 1 and 5 and Comparative Examples 6 and 7 of this invention.
[0030] Figure 9 The images show the results of a marine siding experiment conducted on the piezoelectric antifouling coating prepared in Example 1 of this invention. (a), (b), and (c) are photographs of the experimental group substrate on days 0, 20, and 40, respectively; (d), (e), and (f) are photographs of the control group substrate on days 0, 20, and 40, respectively. Detailed Implementation
[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0032] Experimental methods not specified in the examples are generally performed under conventional conditions and as described in the manual, or as recommended by the manufacturer. Unless otherwise specified, the general equipment, materials, reagents, etc. used are commercially available.
[0033] Example 1
[0034] A method for preparing a piezoelectric antifouling coating includes the following steps:
[0035] 1) Add 28 mg of tourmaline to 25 ml of hydrochloric acid solution and sonicate for 30 min to obtain an acid-modified tourmaline solution. Centrifuge the acid-modified tourmaline solution at 5000 r / min for 15 min, wash with methanol, dry, and then add it to 25 ml of dimethyl sulfoxide to disperse, obtaining an acid-modified tourmaline dispersion. Add 28 mg of multi-walled carbon nanotubes to 25 ml of dimethyl sulfoxide and sonicate for 30 min to obtain a multi-walled carbon nanotube dispersion. Mix the above acid-modified tourmaline dispersion and the above multi-walled carbon nanotube dispersion at a volume ratio of 2:1. After ultrasonic dispersion for 30 min, the product was dried in a vacuum drying oven at 70℃ for 45 min to obtain black powder solid particle filler; the filler and epoxy resin were mixed in a mass ratio of 1:3 and added to a mixed solvent (xylene: n-butanol = 7:3), then 1 part Silok-4010, 1 part organic bentonite, 1 part Silok-350 and 2 parts Silok-7066 were added, and the mixture was ground in a conical mill for 1 h, then 593 curing agent was added, the mass ratio of 593 curing agent to epoxy resin was 1:5, and the mixture was dried in an oven at 70℃ for 5 h to obtain a piezoelectric layer;
[0036] 2) 14g of hydroxyl-terminated polybutadiene (HTPB, molecular weight 2000), pentaerythritol triacrylate (PETA), and hexamethylene diisocyanate trimer (HDIT) were mixed at a molar ratio of isocyanate groups (-NCO) to hydroxyl groups (-OH) of 1:1, and then dissolved in a four-necked flask containing tetrahydrofuran. 0.1% (w / w) of an organic bismuth catalyst was added, and the mixture was reacted at 70°C for 3.5h under a nitrogen atmosphere to obtain a reaction initiator. Then, the reaction initiator and polydimethylsiloxane (PDMS, molecular weight 1000) were added... A mixture of 4% (by mass) and 0.7g of trimethylolpropane (TMP) was prepared with isocyanate groups (-NCO) and hydroxyl groups (-OH) in a molar ratio of 1:1. The mixture was then added to a four-necked flask containing tetrahydrofuran and dissolved. The mixture was reacted at 80°C for 4.5h under a nitrogen atmosphere. After the reaction was completed, the solvent was removed by a rotary evaporator to obtain a modified polyurethane solution. A 20% (by mass) concentration of trimethylolpropane triacrylate (TMPTA) was added to the modified polyurethane solution to make the mass concentration of the modified polyurethane solution 80%, thus obtaining a hydrophobic modified polyurethane coating.
[0037] 3) Add 1% by mass of photoinitiator 1173 to the hydrophobic modified polyurethane coating prepared in step 2), mix evenly under ultrasonic oscillation, and then evenly apply it to the surface of the piezoelectric layer prepared in step 1). After UV curing (irradiation power of 1000W, wavelength of 365nm, irradiation distance of 10cm, curing time of 60s), place it in a 70℃ oven to dry for 30min to obtain a piezoelectric antifouling coating.
[0038] The actual image of the acid-modified tourmaline prepared in this embodiment is shown below. Figure 1 As shown.
[0039] Infrared spectroscopy was performed on the hydroxyl-terminated polybutadiene (HTPB), reaction initiator (HTPB-HDIT), and modified polyurethane (Si-PU) in this embodiment. The results are as follows: Figure 2 As shown:
[0040] from Figure 2 As can be seen from the data, HTPB-HDIT, compared to unreacted HTPB, showed a higher concentration at 2270 cm⁻¹. -1 There is a relatively large peak at 3401 cm⁻¹, which is caused by the stretching vibration of the N=C=O bond; the two peaks of the stretching and deformation vibrations of the NH group are at 3401 cm⁻¹. -1 and 1535cm -1 Nearby, the results showed that HTPB reacted with an isocyanate in HDIT; 2270 cm⁻¹ in Si-PU -1 The disappearance of the isocyanate band at 1260 cm⁻¹ proves that the isocyanate has completely reacted. -1The sharp peak and 808cm -1 Both peaks at 1070 cm⁻¹ originate from Si-CH₃. -1 The absorption at this point is attributed to the Si-O-Si bonds in the PDMS molecule.
[0041] The surface of the piezoelectric antifouling coating prepared in this embodiment was observed by electron microscopy, and the results are as follows: Figure 3 As shown:
[0042] from Figure 3 As can be seen, the surface of the hydrophobic modified polyurethane coating (a) is smooth; the piezoelectric coatings (b, c, d) are composed of protruding and flat resins, and filler particles can be seen wrapped in the resin and uniformly dispersed in the epoxy resin coating, with a filler particle size of about 2 μm.
[0043] Following the method in step 1) of this embodiment, after adding 593 curing agent, it is coated onto the surface of the iron substrate, and then dried in an oven at 70°C for 5 hours to obtain a piezoelectric layer coated on the iron substrate. Continuing with the methods in steps 2) and 3), a piezoelectric antifouling coating is finally obtained on the iron substrate. Specific examples are shown below. Figure 4 As shown.
[0044] Example 2
[0045] The preparation method of the piezoelectric antifouling coating provided in this embodiment is basically the same as that in Embodiment 1, except that in step 1), hydrochloric acid is replaced with an equal amount of nitric acid.
[0046] Example 3
[0047] The preparation method of the piezoelectric antifouling coating provided in this embodiment is basically the same as that in embodiment 1. The difference is that in step 1), the filler and epoxy resin are mixed in a mass ratio of 1:2.
[0048] Example 4
[0049] The preparation method of the piezoelectric antifouling coating provided in this embodiment is basically the same as that in Embodiment 1, except that in step 2), the mass concentration of polydimethylsiloxane added is 2%.
[0050] Example 5
[0051] The preparation method of the piezoelectric antifouling coating provided in this embodiment is basically the same as that in Example 1, except that in step 2), 10% of trimethylolpropane triacrylate is added.
[0052] Comparative Example 1
[0053] The preparation method of the piezoelectric antifouling coating provided in this comparative example is basically the same as that in Example 1, except that in step 1), the tourmaline is not acid-modified.
[0054] Comparative Example 2
[0055] The preparation method of the piezoelectric antifouling coating provided in this comparative example is basically the same as that in Example 1, except that no filler is added to the piezoelectric layer in step 1).
[0056] Comparative Example 3
[0057] The preparation method of the piezoelectric antifouling coating provided in this comparative example is basically the same as that in Example 1, except that in step 1), the filler and epoxy resin are mixed in a mass ratio of 1:1.
[0058] Comparative Example 4
[0059] The preparation method of the piezoelectric antifouling coating provided in this comparative example is basically the same as that in Example 1, except that in step 2), the hydroxyl-terminated polybutadiene is replaced with an equal amount of hydroxyl-terminated polycaprolactone.
[0060] Comparative Example 5
[0061] The preparation method of the piezoelectric antifouling coating provided in this comparative example is basically the same as that in Example 1, except that in step 2), the mass concentration of polydimethylsiloxane added is 6%.
[0062] Comparative Example 6
[0063] The preparation method of the piezoelectric antifouling coating provided in this comparative example is basically the same as that in Example 1, except that in step 2), trimethylolpropane triacrylate is not added.
[0064] Comparative Example 7
[0065] The preparation method of the piezoelectric antifouling coating provided in this comparative example is basically the same as that in Example 1, except that in step 2), 30% by mass of trimethylolpropane triacrylate is added.
[0066] Performance testing
[0067] The output voltage of the piezoelectric layers prepared in Example 1 and Comparative Example 2 was tested. Specifically, an open-circuit voltage test was performed using an electrochemical workstation, with a force of 40 N applied at 2-second intervals for a total test duration of 30 seconds. The results are as follows: Figure 5 As shown:
[0068] from Figure 5 As can be seen from the data, the piezoelectric voltage of the piezoelectric layer prepared in Example 1 is -6 to 9V, while the piezoelectric layer prepared in Comparative Example 2 has almost no piezoelectricity. The results show that the addition of filler makes the piezoelectric layer piezoelectric.
[0069] The flexibility and mechanical properties of the piezoelectric layers prepared in Examples 1, 2 and Comparative Example 1 were tested according to the method in GB / T 9753-2007 "Cupping Test of Paints and Varnishes". The results are shown in Table 1 below:
[0070] Table 1. Cupping value test results of piezoelectric layers
[0071] Cupping value (mm) Example 1 6.84 Example 2 6.02 Comparative Example 1 4.40
[0072] As can be seen from the data in Table 1, the cupping value of tourmaline increases after acid modification. Therefore, the piezoelectric layer prepared using acid-modified tourmaline as raw material has better flexibility and mechanical properties, and the effect is even better after hydrochloric acid modification.
[0073] The mechanical properties of the piezoelectric layers prepared in Examples 1, 3 and Comparative Example 3 were tested, and the results are as follows: Figure 6 As shown:
[0074] from Figure 6 As can be seen, as the filler content increased from Example 1 (filler to epoxy resin ratio of 1:3) to Comparative Example 3 (filler to epoxy resin ratio of 1:1), the coating became brittle. Therefore, when the filler to epoxy resin ratio is 1:(1.5-3), the prepared piezoelectric layer has better mechanical strength.
[0075] The adhesion of the hydrophobic modified polyurethane coatings prepared in Example 1 and Comparative Example 4 was tested using the method in GB / T 1720-1979 "Determination of Adhesion of Coating Films".
[0076] The results showed that the hydrophobic modified polyurethane coating prepared in Example 1 was rated as Grade 1, while the hydrophobic modified polyurethane coating prepared in Example 3 was rated as Grade 2. Therefore, the use of hydroxyl-terminated polybutadiene in this invention can improve adhesion and facilitate bonding with the piezoelectric layer.
[0077] The hydrophobic modified polyurethane coatings prepared in Examples 1, 4, and Comparative Example 5 were subjected to water contact angle tests. Specifically, the hydrophobic modified polyurethane coatings were coated on a 15mm × 10mm glass slide. A 5μL droplet was placed on the test surface using a syringe. The contact angle was measured as the average of five points for each sample. Digital images of the droplet profile were captured using a charge-coupled device camera, and the contact angle was evaluated using a goniometric method. The results are as follows. Figure 7 As shown:
[0078] from Figure 7As can be seen, the hydrophobicity of the prepared hydrophobic modified polyurethane coating increases with the increase of the dimethylsiloxane content. When the dimethylsiloxane content is 6% (Comparative Example 5), the ductility and elastic modulus of the coating decrease. Therefore, the coating performance is optimal when the amount of dimethylsiloxane added is controlled between 2-5%.
[0079] Tensile tests were conducted on the hydrophobic modified polyurethane coatings prepared in Examples 1 and 5 and Comparative Examples 6 and 7. Specifically, four tensile specimens of each coating were prepared into strips (120 mm × 20 mm × 2 mm) and stretched at a speed of 50 mm / min at room temperature. The results are as follows. Figure 8 As shown:
[0080] from Figure 8 As can be seen, the tensile strength of the hydrophobically modified polyurethane coating increases with the increase of trimethylolpropane triacrylate (TMT) content. When the TMT content is 30% (Comparative Example 7), the coating becomes brittle after curing, and the adhesion decreases sharply. Therefore, the coating performance is optimal when the TMT content is controlled between 10-25%.
[0081] Application testing
[0082] Following the method in step 1) of Example 1, after adding 593 curing agent, it is coated on the substrate surface and then dried in an oven at 70°C for 5 hours to obtain a piezoelectric layer coated on the substrate. Following the methods in steps 2) and 3), a piezoelectric antifouling coating is finally obtained on the substrate, which is the experimental group substrate. At the same time, an identical substrate is taken and an epoxy resin layer is coated on its surface to obtain the control group substrate.
[0083] The experimental and control substrates were immersed in seawater at depths of 0.5–1.5 m, and were removed on days 0, 20, and 40 for photographic recording of biofouling. The results are as follows: Figure 9 As shown.
[0084] The results showed that, in the control group, the substrate surface was covered with a large amount of seaweed on day 20, with a coverage area of 76.2%, while on day 40, large marine organisms such as mussels and barnacles grew on the surface, with a fouling coverage area of 89.7%. In the experimental group of this invention, the substrate surface had a small amount of seaweed on day 20, which could be easily removed by shear force, with a surface fouling attachment rate of 10.9%, and on day 40, only a very small amount of barnacles grew, with a surface attachment rate of 27.1%.
[0085] The above results indicate that the piezoelectric antifouling coating of the present invention can reduce the attachment of large marine organisms while also killing marine microorganisms attached to the coating surface.
[0086] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.
[0087] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A method for preparing a piezoelectric antifouling coating, characterized in that, Includes the following steps: Acid-modified tourmaline dispersion and multi-walled carbon nanotube dispersion are mixed and dispersed. After drying, the product is used to obtain a filler. The filler, epoxy resin and additives are added to an organic solution for grinding. Then, a curing agent is added and dried to obtain a piezoelectric layer. A modified polyurethane solution is provided, wherein the modified polyurethane solution is obtained by reacting hexamethylene diisocyanate trimer with hydroxyl-terminated polybutadiene and polydimethylsiloxane; An initiator is added to the modified polyurethane solution, and then coated onto the surface of the piezoelectric layer. After UV curing and drying, the piezoelectric antifouling coating is obtained. Before adding the initiator to the modified polyurethane solution, the method further includes adding trimethylolpropane triacrylate to the modified polyurethane solution, wherein the mass concentration of the added trimethylolpropane triacrylate is 10-25%; the mass concentration of the added initiator is 0.5-1.5%, and the initiator is photoinitiator 1173; the ultraviolet curing includes: an irradiation power of 950-1500W, a wavelength of 360-370nm, an irradiation distance of 5-15cm, and a curing time of 55-65s; The reaction of hexamethylene diisocyanate trimer with hydroxyl-terminated polybutadiene further includes the addition of pentaerythritol triacrylate to the reaction system. The reaction method includes: mixing the hexamethylene diisocyanate trimer, the hydroxyl-terminated polybutadiene, and the pentaerythritol triacrylate at a molar ratio of isocyanate groups to hydroxyl groups of 1:1, dissolving them in an organic solvent, adding an organic bismuth catalyst with a mass concentration of 0.1%, and reacting at 65-75°C for 3-4 hours under an inert atmosphere to obtain a reaction initiator.
2. The method for preparing the piezoelectric antifouling coating according to claim 1, characterized in that, During the preparation of the piezoelectric layer, the volume ratio of the acid-modified tourmaline dispersion to the multi-walled carbon nanotube dispersion is (1.5-2.5):1; The dispersion includes: ultrasonic dispersion for 25-35 minutes; The drying process includes drying at a temperature of 60-80℃ for 40-50 minutes.
3. The method for preparing the piezoelectric antifouling coating according to claim 2, characterized in that, The preparation of the acid-modified tourmaline dispersion includes: adding tourmaline to an acid solution and subjecting it to ultrasonic oscillation to obtain an acid-modified tourmaline solution; after centrifugation, washing and drying, the acid-modified tourmaline solution is added to an organic solution to obtain the acid-modified tourmaline dispersion. The preparation of the multi-walled carbon nanotube dispersion includes: adding multi-walled carbon nanotubes to an organic solution and subjecting them to ultrasonic oscillation to obtain the multi-walled carbon nanotube dispersion. The mass ratio of tourmaline to multi-walled carbon nanotubes is (0.5-1.5):
1.
4. The method for preparing the piezoelectric antifouling coating according to claim 3, characterized in that, In the preparation process of the acid-modified tourmaline dispersion, the mass-to-volume ratio of tourmaline to acid solution is 1:(0.5-1), the mass concentration of acid solution is 3-7%, and it is selected from hydrochloric acid solution or nitric acid solution. The ultrasonic oscillation includes an oscillation time of 25-35 min and a mass ratio of acid-modified tourmaline to organic solution of 1:(0.5-1). In the preparation of the multi-walled carbon nanotube dispersion, the mass ratio of multi-walled carbon nanotubes to organic solution is 1:(0.5-1), and the ultrasonic oscillation includes an oscillation time of 25-35 min.
5. The method for preparing the piezoelectric antifouling coating according to claim 1, characterized in that, In the preparation of the piezoelectric layer, the mass ratio of the filler to the epoxy resin is 1:(1.5-3). The additives include: 0.5-1.5 parts of defoamer, 0.5-1.5 parts of anti-settling agent, 0.5-1.5 parts of leveling agent, and 1.5-2.5 parts of dispersant. The organic solution includes xylene and n-butanol. The grinding is carried out in a conical mill for 0.5-1.5 hours. The drying includes drying at a temperature of 65-75°C for 4.5-5.5 hours.
6. The method for preparing the piezoelectric antifouling coating according to claim 1, characterized in that, The reaction process further includes adding trimethylolpropane to the reaction system while the reaction initiator continues to react with polydimethylsiloxane. The reaction method includes: mixing the reaction initiator, the polydimethylsiloxane, and the trimethylolpropane at a molar ratio of isocyanate groups to hydroxyl groups of 1:1, adding the polydimethylsiloxane at a mass concentration of 2-5%, dissolving it in an organic solvent, reacting it at 65-75°C for 3-4 hours under an inert atmosphere, removing the organic solvent, and obtaining the modified polyurethane solution.
7. The method for preparing the piezoelectric antifouling coating according to claim 1, characterized in that, Drying includes: Dry at a temperature of 65-75℃ for 25-35 minutes.
8. A piezoelectric antifouling coating prepared by the preparation method according to any one of claims 1-7.
9. The application of the piezoelectric antifouling coating of claim 8 in the protection of underwater material surfaces in marine environments.