Preparation method and application of photo-initiated fluorine-containing polyurethane microcapsule

Abstract

This application discloses a method for preparing and applying photo-initiated fluorinated polyurethane microcapsules, belonging to the field of corrosion protection and monitoring technology. The method includes: mixing isophorone diisocyanate, polytetrahydrofuran ether diol, a fluorinated chain extender tetrafluoroethylene dimethyl alcohol, and a catalyst; adding a capping agent hydroxyethyl methacrylate to obtain a fluorinated polyurethane acrylate; mixing this with an active diluent HDDA and a photoinitiator 1173 as a core material; and preparing photo-initiated polyurethane microcapsules via interfacial polymerization. These microcapsules can be dispersed in an aqueous polyurethane matrix to form a self-healing coating, and further integrated with a monitoring system. The monitoring system measures the low-frequency impedance modulus and high-frequency phase angle of the coating in real time using an embedded three-electrode system, and automatically issues an alert when the parameters fall below a threshold. This invention achieves UV-controlled self-repair and electrochemical online monitoring of coating damage, solving the problems of unknown coating condition and unassessable repair effects.

Description

Technical Field

[0001] This application relates to the field of corrosion protection and condition monitoring technology, and in particular to a method for preparing and applying photo-initiated fluorinated polyurethane microcapsules. Background Technology

[0002] The coastal unloader is exposed to a high-salt-spray, high-humidity marine atmospheric environment for a long time. The anti-corrosion coating on its metal structure surface is prone to micro-cracks or damage due to mechanical collisions, stress corrosion, aging and other factors, which leads to rapid corrosion of the base metal.

[0003] Traditional anti-corrosion coatings cannot self-repair after damage, and their condition monitoring relies heavily on regular manual inspections, which is inefficient, costly, and unable to provide early warnings. Microcapsule self-healing technology offers the possibility of autonomous repair of damaged coatings, but current technologies lack real-time monitoring and evaluation methods for the repair process and its effectiveness.

[0004] Therefore, a method for preparing photo-initiated fluorinated polyurethane microcapsules and their application are provided. Summary of the Invention

[0005] This application aims to provide a method for preparing photo-initiated fluorinated polyurethane microcapsules and the application of these microcapsules in monitoring the self-healing damage of coatings on coastal unloading machines. By combining the self-healing coating of fluorinated polyurethane microcapsules with an embedded electrochemical monitoring module, the autonomous repair of coating damage and real-time evaluation of the repair effect can be achieved.

[0006] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, this application provides a method for preparing photoinitiated fluorinated polyurethane microcapsules, comprising the following steps: Isophorone diisocyanate, polytetrahydrofuran ether diol, fluorinated chain extender tetrafluoroterephthalic acid and catalyst are mixed and reacted at 80℃-90℃ for 2-4 hours. Hydroxyethyl methacrylate is added as a capping agent and reacted at 70℃-90℃ for 2-4 hours. A polymerization inhibitor is added to obtain fluorinated polyurethane acrylate. The fluorinated polyurethane acrylate was mixed with reactive diluent HDDA and photoinitiator 1173 as the core material, and photoinitiated polyurethane microgels were prepared by interfacial polymerization.

[0007] Furthermore, the amount of the fluorinated chain extender tetrafluoroterephthalic acid accounts for 2%-10% of the total mass of the polyurethane monomer.

[0008] Furthermore, the amount of the fluorinated chain extender tetrafluoroterephthalic acid accounts for 4%-8% of the total mass of the polyurethane monomer.

[0009] Secondly, this application provides a self-healing coating comprising: The self-healing coating comprises an aqueous polyurethane matrix and photoinitiating polyurethane microcapsules dispersed within the aqueous polyurethane matrix. The photoinitiating polyurethane microcapsules are prepared by the method described above.

[0010] Furthermore, the photoinitiated polyurethane microcapsules constitute 2%-10% of the mass fraction of the self-healing coating.

[0011] Thirdly, this application provides a self-healing coating monitoring system to reduce coating damage on offshore unloading machines, comprising a self-healing coating and a monitoring system. The self-healing coating is the aforementioned self-healing coating; The monitoring system includes a sensor module, a data acquisition and processing module, and an evaluation and early warning module. The sensor module measures the electrochemical impedance parameters of the coating. The data acquisition and processing module acquires and processes these electrochemical impedance parameters. The evaluation and early warning module evaluates the coating condition based on the processed data and issues an early warning signal when the evaluation result indicates coating damage or ineffective repair.

[0012] Furthermore, the sensor module is a three-electrode system embedded in or near the coating, the three-electrode system including a working electrode, a reference electrode, and a counter electrode.

[0013] Furthermore, the electrochemical impedance parameters include low-frequency impedance magnitude and high-frequency phase angle. The evaluation and early warning module has preset low-frequency impedance magnitude thresholds and / or high-frequency phase angle thresholds. When the low-frequency impedance magnitude obtained by the data acquisition and processing module is lower than the low-frequency impedance magnitude threshold and / or the high-frequency phase angle is lower than the high-frequency phase angle threshold, the evaluation and early warning module issues an early warning signal.

[0014] Furthermore, the low-frequency impedance modulus threshold is 1.0 × 10⁻⁶. 5 Ω·cm², where the high-frequency phase angle threshold is 50°.

[0015] Fourthly, this application provides a method for monitoring and early warning of coating damage based on self-healing coatings, comprising the following steps: The electrochemical impedance parameters of the coating are measured using a sensor module embedded in or near the self-healing coating. The electrochemical impedance parameters of the coating are measured using a sensor module embedded in or near the self-healing coating. The electrochemical impedance parameters were collected, and the low-frequency impedance magnitude and high-frequency phase angle were extracted; the extracted low-frequency impedance magnitude was compared with 1.0 × 10⁻⁶. 5 The extracted high-frequency phase angle is compared with the 50° threshold by comparing the Ω·cm² threshold. When the low-frequency impedance modulus is less than 1.0 × 10 5When the threshold of Ω·cm² is reached, or when the high-frequency phase angle is lower than the threshold of 50°, a warning signal is issued.

[0016] Compared with the prior art, this application has the following beneficial effects: This application provides a method for preparing photoinitiated fluorinated polyurethane microcapsules. The method involves mixing and reacting isophorone diisocyanate, polytetrahydrofuran ether diol, a fluorinated chain extender tetrafluoroethylene dimethyl alcohol, and a catalyst, followed by the addition of a capping agent hydroxyethyl methacrylate to obtain a fluorinated polyurethane acrylate. This fluorinated polyurethane acrylate is then mixed with an active diluent HDDA and a photoinitiator 1173 as a core material, and photoinitiated polyurethane microcapsules are prepared via interfacial polymerization. Compared to existing microcapsule preparation methods that use epoxy resin core materials and require high-temperature curing, the microcapsule core material prepared in this application contains acrylate double bonds and fluorinated segments that can participate in the photocuring reaction. It can be rapidly cured at room temperature under ultraviolet light irradiation without the need for heating equipment, making it particularly suitable for on-site in-situ repair of large outdoor equipment such as coastal unloading machines, thus solving the technical problem of difficult on-site application of existing self-healing coatings.

[0017] Furthermore, this application controls the amount of the fluorinated chain extender tetrafluoroterephthalic acid (TEPDE) to be 2%-10% of the total mass of the polyurethane monomers, preferably 4%-8%. By introducing fluorinated segments within this range, the fluorine atoms in the core material form a shielding effect on the C-C bonds, and the polymer formed at the repair site exhibits significant hydrophobic properties, capable of blocking electrolyte solutions outside the repair area. Experimental data show that when the amount of fluorinated diol is 6%, the low-frequency impedance modulus of the repaired coating increases from 1.0 × 10⁻⁶ at the time of damage. 4 The value rose from below Ω·cm² to 8.969×10. 5 With a fluorine content exceeding Ω·cm², the high-frequency phase angle recovers from below 10° to above 70.21°, significantly improving corrosion resistance and effectively extending the coating's service life. Compared to coatings without fluorine-containing segments, the fluorine-containing core material of this application improves the corrosion resistance of the repaired area by an order of magnitude.

[0018] Furthermore, this application disperses the photoinitiated fluorinated polyurethane microcapsules prepared by the above method in an aqueous polyurethane matrix to form a self-healing coating, and integrates an embedded three-electrode monitoring system to monitor the low-frequency impedance modulus and high-frequency phase angle of the coating in real time, with a preset value of 1.0 × 10⁻⁶. 5Ω·cm² and 50° are used as early warning thresholds. When microcracks appear in the coating due to damage, the microcapsules rupture to release the core material, which is then cured and repaired under ultraviolet light. Simultaneously, the monitoring system tracks changes in electrochemical parameters in real time: an early warning is triggered when the parameters fall below the threshold, and the warning is automatically lifted when the parameters rise back above the threshold after successful repair. Compared with existing technologies that rely on manual inspection and cannot perceive the coating status in real time, this application achieves non-destructive online assessment of the coating's health status and quantitative judgment of the repair effect, transforming passive maintenance into proactive early warning, significantly improving maintenance efficiency and equipment service reliability. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart illustrating a method for preparing photoinitiated fluorinated polyurethane microcapsules according to an embodiment of this application.

[0021] Figure 2 Comparison of Bode spectra of electrochemical impedance spectroscopy before and after repair of the self-healing coating prepared in the embodiments of this application.

[0022] Figure 3 Comparison of Nyquist images before and after repair using the self-healing coating prepared for the embodiments of this application. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] Example 1 See Figure 1 This application provides a method for preparing photoinitiated fluorinated polyurethane microcapsules, comprising the following steps: IPDI, PTMG1000, and measured amounts of TFB (2%, 4%, 6%, 8%, and 10% of the total mass of polyurethane monomers, respectively), along with catalyst DBTDL, were added to a 250 mL three-necked flask equipped with a stirrer, condenser, and dropping funnel. The mixture was reacted at 85 °C for 3 hours. HEMA was then added at 80 °C and reacted for another 3 hours. After the reaction was complete, a polymerization inhibitor was added to obtain a series of difunctional fluorinated polyurethane acrylates (TFPUAs) with different fluorine contents, designated TF2PUA, TF4PUA, TF6PUA, TF8PUA, and TF10PUA, respectively.

[0025] The prepared TTFPUA was mixed with HDDA and photoinitiator 1173 at a mass ratio of 70:25:5 as the core material, and fluorinated core microcapsules were prepared by interfacial polymerization. The process parameters were: core-to-wall ratio 1:1-1.5, emulsifier concentration 0.5%-2%, homogenization rate 7000-9000 r / min, and homogenization time 10-20 min. The obtained microcapsules had smooth surfaces, uniform size, and an average particle size in the range of 15-35 μm. The corresponding microcapsules were designated as MTF2PUA, MTF4PUA, MTF6PUA, MTF8PUA, and MTF10PUA.

[0026] Example 2 This embodiment provides a more specific method for preparing photo-initiated fluorinated polyurethane microcapsules: The amount of tetrafluoroterephthalic acid (TFB), a fluorinated chain extender, accounts for 6% of the total mass of the polyurethane monomers. 0.1 mol IPDI, 0.05 mol PTMG1000, TFB (approximately 0.006 mol), and DBTDL catalyst (0.1% of the total reactant mass) were added to a 250 mL three-necked flask equipped with a stirrer, condenser, and dropping funnel. The mixture was stirred at 85°C for 3 hours. The temperature was then lowered to 80°C, and 0.05 mol HEMA was added. The reaction was continued for another 3 hours. After the reaction was complete, hydroquinone (0.05% of the total reactant mass), a polymerization inhibitor, was added to obtain fluorinated polyurethane acrylate (TF6PUA).

[0027] The TF6PUA prepared above was mixed with HDDA and photoinitiator 1173 at a mass ratio of 70:25:5 to form the core material. The core material was added to an aqueous solution containing an emulsifier (sodium dodecylbenzenesulfonate, 1% concentration) and dispersed at a homogenization rate of 8000 r / min for 15 min to form a stable emulsion. Then, a wall material prepolymer (melamine-formaldehyde prepolymer, core-to-wall ratio of 1:1.2) was added, and the pH was adjusted to 3.5 with dilute hydrochloric acid. The mixture was stirred at 75°C for 2.5 hours. After the reaction was completed, the mixture was cooled to room temperature, and the product was washed and filtered three times each with acetone, anhydrous ethanol, and deionized water. The product was then vacuum dried at 50°C for 12 hours to obtain photoinitiated polyurethane microcapsules with an average particle size of 20 μm-30 μm.

[0028] Example 3 This embodiment provides another method for preparing photoinitiated fluorinated polyurethane microcapsules, which uses in-situ polymerization instead of interfacial polymerization.

[0029] IPDI, PTMG1000, and measured amounts of TFB (2%, 4%, 6%, 8%, and 10% of the total mass of polyurethane monomers, respectively) and catalyst DBTDL were added to a 250 mL three-necked flask equipped with a stirrer, condenser, and dropping funnel. The mixture was reacted at 85 °C for 3 hours. HEMA was then added at 80 °C and reacted for another 3 hours. After the reaction was complete, a polymerization inhibitor was added to obtain a series of difunctional fluorinated polyurethane acrylates (TFPUA) with different fluorine contents, designated as TF2PUA, TF4PUA, TF6PUA, TF8PUA, and TF10PUA, respectively.

[0030] The prepared TFPUA was mixed with HDDA and photoinitiator 1173 at a mass ratio of 65:30:5 to form the core material. The core material was added to an aqueous solution containing emulsifier (OP-10, 1.5%) and dispersed at a homogenization rate of 7500 r / min for 20 min to form a stable emulsion. Melamine, urea, and formaldehyde were mixed at a mass ratio of 1:1.5:3, and the pH was adjusted to 8.5 with triethanolamine. The mixture was stirred at 70°C for 1 hour to prepare a melamine-urea-formaldehyde prepolymer as the wall material. The wall material prepolymer was slowly added dropwise to the above emulsion, and the pH was adjusted to 3.0 with dilute hydrochloric acid. The mixture was stirred at 80°C for 3 hours. After the reaction, the mixture was cooled to room temperature, and the product was washed and filtered three times each with acetone, anhydrous ethanol, and deionized water. The product was then vacuum dried at 60°C for 10 hours to obtain photoinitiated polyurethane microcapsules with an average particle size of 10 μm-25 μm.

[0031] Example 4 This embodiment provides a self-healing coating and its preparation method: Microcapsules with different fluorine contents prepared in Example 1 were added to aqueous polyurethane emulsion at a mass fraction of 5%, stirred evenly, and then coated onto the surface of a simulated sample (tinplate) of a coastal unloading machine. The coatings were cured at room temperature to form self-healing coatings, and the corresponding coatings were designated as MTF2PUA, MTF4PUA, MTF6PUA, MTF8PUA, and MTF10PUA coatings.

[0032] The self-healing coating comprises an aqueous polyurethane matrix and photoinitiating polyurethane microcapsules dispersed within the aqueous polyurethane matrix. The photoinitiating polyurethane microcapsules are prepared by the preparation method described in Example 1.

[0033] In a preferred embodiment, the photoinitiated polyurethane microcapsules constitute 2%-10% of the self-healing coating by mass. In a more preferred embodiment, the photoinitiated polyurethane microcapsules constitute 5% of the self-healing coating by mass.

[0034] This embodiment provides a more specific method for preparing a self-healing coating: Photoinitiated polyurethane microcapsules (TF6PUA, average particle size 20μm-30μm) prepared in Example 2 are added to an aqueous polyurethane emulsion at a mass fraction of 5%. The mixture is stirred at 300 rpm for 30 min at room temperature to ensure uniform dispersion of the microcapsules. The mixed emulsion is then coated onto the metal substrate surface of a coastal unloader to a thickness of 150μm-200μm. The coating is then allowed to cure naturally at room temperature for 24 hours to form a self-healing coating.

[0035] Example 5 This embodiment provides a more specific method for preparing a self-healing coating. Photoinitiated polyurethane microcapsules (TF6PUA, average particle size 20μm-30μm) prepared in Example 3 are added to an aqueous polyurethane emulsion at a mass fraction of 5%. The mixture is stirred at 300 rpm for 30 min at room temperature to ensure uniform dispersion of the microcapsules. The mixed emulsion is then coated onto the metal substrate surface of a coastal unloader to a thickness of 150μm-200μm. After natural curing at room temperature for 24 hours, a self-healing coating is formed.

[0036] Example 6 This application provides a self-healing coating monitoring system to reduce coating damage on coastal unloading machines.

[0037] The self-healing coating monitoring system includes a self-healing coating and a monitoring system. The self-healing coating is the one prepared in Example 2, specifically an MTF6PUA coating (6% fluorine content). The monitoring system includes a sensor module, a data acquisition and processing module, and an evaluation and early warning module. The monitoring system includes a sensor module, a data acquisition and processing module, and an assessment and early warning module.

[0038] The sensor module is used to measure the electrochemical impedance parameters of the coating. In this embodiment, the sensor module is a three-electrode system embedded in or near the coating, including a working electrode, a reference electrode, and a counter electrode. The sensor module and the coating form an electrochemical measurement circuit, and the impedance response of the coating is measured by applying a small AC voltage signal.

[0039] The data acquisition and processing module is used to acquire and process electrochemical impedance parameters. Electrically connected to the sensor module, it receives the raw electrochemical data measured by the sensor module and performs filtering, transformation, and feature extraction on the data.

[0040] The assessment and early warning module evaluates the coating condition based on processed data and issues an early warning signal when the assessment results indicate coating damage or poor repair effectiveness. Connected to the data acquisition and processing module, the module receives processed electrochemical data and determines whether coating damage has occurred and whether repair was successful by comparing the measured data with a preset normal state benchmark. When coating damage or poor repair effectiveness is determined, the assessment and early warning module issues an early warning signal that can be recognized by the operator, such as an audible and visual alarm, remote push notification, or status indication from the central control system.

[0041] In this embodiment, by integrating the self-healing coating with a monitoring system, autonomous repair of coating damage and real-time evaluation of the repair effect are achieved. When the coating develops microcracks due to damage, the pre-embedded photo-initiated polyurethane microcapsules rupture to release the core material. Under ultraviolet light irradiation, the fluorinated polyurethane acrylate and reactive diluent in the core material undergo free radical polymerization and curing under the action of a photoinitiator, achieving self-repair. Simultaneously, the monitoring system tracks the coating's corrosion protection status in real time by periodically or continuously measuring the coating's electrochemical impedance. For successfully repaired coatings, the electrochemical impedance parameters show a significant recovery; if the repair fails or the damage is severe, the relevant parameters will remain below the safety threshold, and the system will promptly issue a maintenance alarm.

[0042] In this embodiment, the low-frequency impedance modulus threshold is 1.0 × 10⁻⁶. 5 Ω·cm², with a high-frequency phase angle threshold of 50°. When the low-frequency impedance modulus is less than 1.0 × 10⁻⁶... 5 When the Ω·cm² or high-frequency phase angle is less than 50°, the system determines that the coating is damaged or the repair effect is poor, and triggers an early warning signal.

[0043] Example 7 This embodiment provides a method for monitoring and early warning of coating damage based on self-healing coatings.

[0044] The method includes the following steps: The electrochemical impedance parameters of the self-healing coating were measured using a sensor module embedded in or near the coating. The sensor module employed a miniature three-electrode system embedded in or near the coating, and its impedance response at different frequencies was measured by applying a small AC voltage signal. The self-healing coating was the one prepared in Example 2.

[0045] Electrochemical impedance parameters are collected, and low-frequency impedance magnitude and high-frequency phase angle are extracted. The raw data measured by the sensor module is received through the data acquisition and processing module, filtered and transformed, and the impedance magnitude at low frequency (0.01 Hz) and high-frequency phase angle are extracted from the electrochemical impedance spectrum. 4 Hz-10 5 The phase angle value at Hz.

[0046] The extracted low-frequency impedance modulus was compared with 1.0 × 10⁻⁶. 5 The extracted high-frequency phase angle is compared with the 50° threshold by comparing the Ω·cm² threshold.

[0047] When the low-frequency impedance modulus is less than 1.0 × 10 5 An early warning signal is issued when the Ω·cm² threshold or the high-frequency phase angle falls below the 50° threshold. In actual monitoring, periodic or continuous measurement methods can be used. When the coating is in good condition, the low-frequency impedance modulus is typically higher than 1.0 × 10⁻⁶. 5 The low-frequency impedance modulus is Ω·cm², and the high-frequency phase angle is higher than 50°. When the coating is damaged, the electrolyte solution seeps into the coating, and the low-frequency impedance modulus rapidly drops below the threshold. Simultaneously, the high-frequency phase angle also decreases accordingly. At this point, the system triggers a warning signal, indicating that the coating is damaged and requires attention or repair. After repair, if successful, the low-frequency impedance modulus recovers to 1.0 × 10⁻⁶ Ω·cm². 5 If the value is above Ω·cm² and the high-frequency phase angle rises to above 50°, the warning signal will be automatically lifted; if the repair fails or the damage is severe and the relevant parameters remain below the threshold, the system will continue to issue warnings, prompting that manual intervention is required.

[0048] In this embodiment, the measurement frequency of the low-frequency impedance modulus is 0.01Hz, and the measurement frequency range of the high-frequency phase angle is 10°. 4 Hz-10 5 Hz. At this frequency setting, the low-frequency impedance modulus can sensitively reflect changes in the barrier performance of the coating, and the high-frequency phase angle can sensitively reflect changes in the dielectric properties of the coating. The combination of the two can achieve an accurate assessment of coating damage and repair effects.

[0049] Example 8 In this embodiment, the integration and functional verification of the self-healing coating monitoring system are described.

[0050] Before applying the MTF6PUA coating (6% fluorine content), a miniature three-electrode system was pre-embedded in the sample substrate. The coating was artificially scratched, and the monitoring system immediately detected a low-frequency impedance |Z|0. 01 Hz < 1.0 × 10 4 Ω·cm², phase angle <10°, triggering a "damage" warning. After repair by ultraviolet light irradiation, |Z| 0. 01 Hz rebounded to >8.969×10 5 The phase angle recovered to >70.21°, and the warning was lifted. This verifies the effectiveness of the system in identifying coating damage and evaluating the repair effect.

[0051] like Figure 2 As shown, the Bode plot of the self-healing coating in 3.5% NaCl solution indicates that the coating impedance increases with the increase of the amount of fluorinated diol in the core material TFPUA. This is because, when the amount of microcapsules added to the coating is constant, the anti-corrosion performance of the self-healing coating is mainly determined by the anti-corrosion performance of the core material in the microcapsules. When microcracks appear in the coating, the fluorinated core material in the microcapsules flows out, and the fluorine atoms in the core material form a shielding effect on the C-C bonds. At this time, the polymer formed at the repair site exhibits more obvious hydrophobic properties, which prevents the electrolyte solution from entering the repair site, thereby improving the anti-corrosion performance of the repair effect. When 6% fluorinated diol is introduced, the low-frequency impedance value increases from 2.665 × 10⁻⁶. 5 Ω·cm² increased to 1.038×10 6 The Ω·cm² value is increased by an order of magnitude, improving corrosion resistance on the basis of self-healing and extending the service life of the coating.

[0052] like Figure 3 As shown, the Nyquist plots of polyurethane microcapsule self-healing coatings with different fluorine contents indicate that as the amount of fluorinated diol in the TFPUA core material increases, the radius of the Nyquist curve of the repaired coating increases, indicating improved corrosion resistance. When the amount of fluorinated diol is 6%, the increase in the Nyquist curve radius is significant; further increases in dosage result in a slower change in radius. This suggests that a 6% addition of fluorinated diol to the coating microcapsules achieves both excellent corrosion resistance and cost-effectiveness.

[0053] Based on the above experimental results, the dosage of fluorinated chain extender TFB within the range of 2%-10% can prepare microcapsules with self-healing function and give the coating superior anti-corrosion performance compared to coatings without fluorinated chain segments. Among them, when the dosage is 4%-8%, especially 6%, the hydrophobicity, impedance value and mechanical properties of the repaired coating reach the optimal balance.

[0054] The embodiments described above are merely preferred embodiments of this application, 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 improvements and substitutions without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the scope of the claims.

Claims

1. A method for preparing photo-initiated fluorinated polyurethane microcapsules, characterized in that, Includes the following steps: Isophorone diisocyanate, polytetrahydrofuran ether diol, fluorinated chain extender tetrafluoroterephthalic acid and catalyst are mixed and reacted at 80℃-90℃ for 2-4 hours. Hydroxyethyl methacrylate is added as a capping agent and reacted at 70℃-90℃ for 2-4 hours. A polymerization inhibitor is added to obtain fluorinated polyurethane acrylate. The fluorinated polyurethane acrylate was mixed with reactive diluent HDDA and photoinitiator 1173 as the core material, and photoinitiated polyurethane microcapsules were prepared by interfacial polymerization.

2. The method for preparing photo-initiated fluorinated polyurethane microcapsules according to claim 1, characterized in that, The amount of the fluorinated chain extender tetrafluoroterephthalic acid is 2%-10% of the total mass of the polyurethane monomer.

3. The method for preparing photo-initiated fluorinated polyurethane microcapsules according to claim 1, characterized in that, The amount of the fluorinated chain extender tetrafluoroterephthalic acid accounts for 4%-8% of the total mass of the polyurethane monomer.

4. A self-healing coating, characterized in that, The self-healing coating comprises an aqueous polyurethane matrix and photoinitiating polyurethane microcapsules dispersed within the aqueous polyurethane matrix; the photoinitiating polyurethane microcapsules are prepared by the preparation method according to any one of claims 1 to 3.

5. The self-healing coating according to claim 4, characterized in that, The photoinitiated polyurethane microcapsules have a mass fraction of 2%-10% in the self-healing coating.

6. A self-healing coating monitoring system for reducing coating damage on coastal unloading machines, characterized in that, include: Self-healing coating; The monitoring system includes a sensor module, a data acquisition and processing module, and an assessment and early warning module. The sensor module is used to measure the electrochemical impedance parameters of the coating; The data acquisition and processing module is used to acquire and process the electrochemical impedance parameters; The assessment and early warning module is used to assess the coating status based on the processed data and issue an early warning signal when the assessment result indicates that the coating is damaged or the repair effect is poor.

7. A self-healing coating monitoring system for reducing coating damage on coastal unloading machines according to claim 6, characterized in that, The sensor module is a three-electrode system embedded in or near the coating, and the three-electrode system includes a working electrode, a reference electrode, and a counter electrode.

8. The self-healing coating monitoring system according to claim 6, characterized in that, The electrochemical impedance parameters include low-frequency impedance magnitude and high-frequency phase angle; the evaluation and early warning module is preset with a low-frequency impedance magnitude threshold and / or a high-frequency phase angle threshold. When the low-frequency impedance magnitude obtained by the data acquisition and processing module is lower than the low-frequency impedance magnitude threshold and / or the high-frequency phase angle is lower than the high-frequency phase angle threshold, the evaluation and early warning module issues an early warning signal.

9. The self-healing coating monitoring system according to claim 8, characterized in that, The low-frequency impedance modulus threshold is 1.0 × 10⁻⁶. 5 Ω·cm², where the high-frequency phase angle threshold is 50°.

10. A method for monitoring and early warning of coating damage based on self-healing coatings, characterized in that, Includes the following steps: The electrochemical impedance parameters of the coating are measured using a sensor module embedded in or near the self-healing coating. The electrochemical impedance parameters were collected, and the low-frequency impedance magnitude and high-frequency phase angle were extracted. The extracted low-frequency impedance modulus was compared with 1.0 × 10⁻⁶. 5 The extracted high-frequency phase angle is compared with the 50° threshold by comparing the Ω·cm² threshold. When the low-frequency impedance modulus is less than 1.0 × 10 5 When the threshold of Ω·cm² is reached, or when the high-frequency phase angle is lower than the threshold of 50°, a warning signal is issued.

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