Near-infrared rapid response precision self-repairing anticorrosive coating and preparation method and self-repairing method thereof, resin material containing dynamic chemical bond and application thereof

Abstract

The application discloses near-infrared fast-response precise self-repairing anticorrosive paint and a preparation method and a self-repairing method thereof, a resin material containing a dynamic chemical bond and application thereof, and relates to the technical field of high polymer materials. The preparation method of the near-infrared fast-response precise self-repairing anticorrosive paint disclosed by the application adds AGO (amino-functionalized graphene oxide) as a photo-thermal filler of a coating system, endows the coating with photo-thermal conversion performance, and adopts vanillin and an epoxy resin to construct a prepolymer containing an aldehyde group at the end. The amine group on the surface of AGO after mixing the prepolymer and AGO can react with the aldehyde group in the prepolymer to form a chemical bond through amine-aldehyde condensation reaction. The coating is solidified by using a polyether amine, the filler can keep stable dispersion, is not easy to agglomerate, and therefore the coating has excellent self-repairing capability and anticorrosion performance.

Description

Technical Field

[0001] This invention relates to near-infrared fast-response precision self-healing anti-corrosion coatings and their preparation and self-healing methods, resin materials containing dynamic chemical bonds and their applications, and relates to the field of polymer materials technology. Background Technology

[0002] Metallic materials are frequently exposed to corrosive environments, resulting in various forms of corrosion, which can lead to unexpected failures, personal injury, and economic losses. To prevent corrosion, an effective method is to introduce polymer coatings onto the surface of metallic materials. However, over time, these polymer coatings may become incomplete due to external physical damage, and this incompleteness can reduce the coating's protective ability against the metal surface, thus limiting the application of anti-corrosion coatings. Self-healing polymer coatings can solve this problem. In recent years, self-healing coatings that can spontaneously heal surface damage and restore protective properties have received increasing attention. Typically, the self-healing function of these coatings is achieved in two ways: (1) by repairing the coating matrix through reversibly generated chemical bonds or reversible molecular arrangement; (2) by the self-release of healing agents contained in the coating matrix, such as reactive monomers, thermoplastic additives, and corrosion inhibitors, into the coating defects after being subjected to external damage. The self-healing effect of polymer coatings is usually initiated or enhanced by external stimuli such as heat, light, magnetic fields, and pH changes. Current research on self-healing coatings mainly focuses on thermally initiated coatings. However, thermal initiation requires manual intervention, which is difficult to operate, and the heating process of thermally initiated self-healing methods can damage the structure of the damaged part of the material and the surrounding polymer material. Compared with the simple thermally initiated self-healing method, the self-healing process initiated by both light and heat has several advantages in the practical application of self-healing coating materials: (1) it can be remotely activated to heal the damaged area; (2) it is highly controllable and can start / stop the self-healing process instantly; (3) the light can be focused on the selected area without significantly interfering with the intact coating; and (4) the healing process is very fast (usually within minutes).

[0003] In the preparation of photothermally initiated self-healing polymer coatings, fillers with photothermal effects, such as carbon-based materials, metal-based nanoparticles, organic polymers, and inorganic semiconductor materials, are typically added to the polymer matrix. Graphene nanosheets (GNPs), as a two-dimensional carbon material, possess excellent photothermal conversion efficiency, high impermeability, and high specific surface area. Therefore, they can not only endow epoxy coatings with photothermal conversion capabilities but also extend the path of corrosive media to the metal surface by dispersing in the polymer matrix to form a "maze," thus playing a corrosion-inhibiting role. When mixed with epoxy resin, GNPs can synergistically utilize physical shielding and corrosion inhibition effects, significantly improving the corrosion resistance of epoxy resin coatings. However, GNPs have poor dispersibility and high surface energy, making them prone to agglomeration in epoxy resins, which limits their application in corrosion protection.

[0004] Existing technology discloses a silane coupling agent-modified graphene oxide-reinforced epoxy resin composite coating. First, KH550 is used to modify GO (graphene oxide) nanosheets. Then, the modified GO nanosheets are directly added to epoxy resin, followed by the addition of a curing agent. After curing, an epoxy resin coating incorporating modified GO is obtained. The addition of modified GO improves the corrosion resistance of the epoxy resin coating. However, this existing technology does not address the coating's self-healing ability. Furthermore, the modified GO and epoxy resin in this composite material are simply mixed through physical processes, and the modified GO in the coating may still agglomerate. This limits the coating's corrosion resistance and also affects its self-healing ability under the influence of light and heat. Summary of the Invention

[0005] To address the problem of filler agglomeration in existing photothermal self-healing polymer coatings, which affects the coating's corrosion resistance and self-healing capabilities, this invention provides a method for preparing a near-infrared rapid response precision self-healing anti-corrosion coating. AGO (amino-functionalized graphene oxide) is added as a filler, and vanillin and epoxy resin are used to construct a prepolymer. After mixing the prepolymer and AGO, the amino groups on the AGO surface can undergo an amine-aldehyde condensation reaction with the aldehyde groups in vanillin to form chemical bonds. This allows the filler in the coating, prepared by curing the coating, to remain stably dispersed and less prone to agglomeration.

[0006] Another objective of this invention is to provide a near-infrared fast-response, precise self-healing anti-corrosion coating.

[0007] Another objective of this invention is to provide a self-healing method for a near-infrared fast-response precision self-healing anti-corrosion coating.

[0008] Another object of the present invention is to provide a resin material containing dynamic chemical bonds.

[0009] Another object of the present invention is to provide an application of a resin material containing dynamic chemical bonds as a film-forming substance in the preparation of photoresponsive self-healing coatings or coatings.

[0010] The above-mentioned objective of this invention is achieved through the following technical solution:

[0011] A method for preparing a near-infrared fast-response precision self-healing anti-corrosion coating includes the following steps:

[0012] S1. GO is modified using an amino-containing modifier to obtain AGO after modification;

[0013] S2. Mix vanillin, epoxy resin and catalyst and react at a temperature of 100-200℃ for 6-10 hours to obtain a prepolymer. The molar ratio of vanillin to epoxy resin is (1.5-2.5):1.

[0014] S3. Disperse the AGO obtained in S1 in DMF using ultrasound, then mix it with the prepolymer obtained in step S2. After mixing, add polyetheramine to react and obtain a near-infrared fast-response precision self-healing anti-corrosion coating. The mass ratio of AGO to prepolymer is (0.1~1):100.

[0015] In step S1 of this invention, an amino-containing modifier is used to modify GO (graphene oxide), which can introduce amino groups onto the surface of GO to obtain AGO (amino-functionalized graphene oxide).

[0016] In the preparation process of the self-healing anti-corrosion coating of this invention, E-44 epoxy resin is modified into an aldehyde-terminated prepolymer by vanillin, and a resin system containing dynamic imine bonds is synthesized using polyetheramine (T403 and / or D400 type polyetheramine) as a chain extender and curing agent. Then, an appropriate amount of amino-functionalized graphene oxide (AGO) is added as a photothermal filler. AGO is covalently grafted onto the resin system, increasing the dispersibility of the filler in the resin. The uniformly dispersed AGO endows the coating with excellent photothermal conversion capabilities, improving the mechanical properties and anti-corrosion performance of the composite material. This coating solves the problems of rapid self-healing and high strength of materials, and can achieve rapid damage repair through near-infrared light irradiation, extending the service life of the coating.

[0017] Specifically, in step S2, during the preparation of the prepolymer, the epoxy groups at the ends of the epoxy resin react with the hydroxyl groups in vanillin, transforming the terminal groups of the resulting prepolymer into aldehyde groups introduced by vanillin. In step S3, the polyetheramine can form dynamic imine bonds with the aldehyde groups at the ends of the prepolymer, endowing the coating obtained by curing the coating with self-healing properties. Similarly, in step S3, after adding AGO, the surface of AGO also contains amino groups, which can undergo amine-aldehyde condensation reactions with aldehyde groups. Therefore, AGO can be grafted into the coating system through covalent bonds, which improves the dispersibility of AGO in the coating obtained by curing the coating and reduces its agglomeration probability. This not only gives the coating excellent anti-corrosion properties but also enables the coating to have stable self-healing ability when it undergoes self-healing after being subjected to external physical damage. The appropriate molar ratio of vanillin and epoxy resin in step S2 and the appropriate mass ratio of AGO to prepolymer in step S3 can enable the aldehyde groups at the end of the prepolymer and the amino groups on the surface of AGO to form a suitable density of bonds after the vanillin and epoxy resin form the prepolymer. This results in the formation of a polymer coating with both excellent anti-corrosion properties and self-healing ability after the addition of polyetheramine.

[0018] In some embodiments, the amino-containing modifier used in step S1 is APTES (3-aminopropyltriethoxysilane).

[0019] In some embodiments, the modification of GO with an amino-containing modifier in step S1 is performed by dispersing GO and the amino-containing modifier in a solvent and reacting them to obtain AGO. Specifically, the modification process involves ultrasonic dispersion of GO and the amino-containing modifier in a solvent. More specifically, the ultrasonic dispersion time is 20–40 min. Specifically, the solvent used in the modification process is ethanol, the reaction temperature is 60–100°C, the reaction time is 4–8 h, and the reaction is carried out under reflux and stirring conditions.

[0020] In some embodiments, during the modification of GO in step S1, water is slowly added under stirring after the reaction is complete to terminate the reaction. More specifically, after terminating the reaction, the mixture is centrifuged at 8000–10000 rpm for 5–15 min, the precipitate is collected, washed, dried, and ground to obtain AGO. More specifically, ethanol is used as the washing solution. More specifically, the drying is carried out at 40–80°C.

[0021] In some embodiments, the molar ratio of GO to the amino-containing modifier in step S1 is (0.5–1.5):1. Controlling the molar ratio of GO to the amino-containing modifier within the above range allows for sufficient amino functionalization modification of GO, which is beneficial for the bonding between the resulting AGO and vanillin, thereby enabling AGO to have good dispersibility and be less prone to agglomeration in the final coating system.

[0022] In some embodiments, the epoxy resin used in step S2 of the present invention is a bisphenol A type epoxy resin. More specifically, the epoxy resin used in step S2 of the present invention is an E-44 type epoxy resin.

[0023] Specifically, the epoxy value of E-44 type epoxy resin is 0.41 to 0.47 mol / 100g.

[0024] The self-healing properties of polymer coatings mainly depend on the content of dynamic imine bonds at the curing crosslinking points. The higher the epoxy value of the epoxy resin, the higher the proportion of terminal aldehyde groups in the prepolymer after forming a prepolymer with vanillin, and the higher the content of dynamic bonds after curing with amine curing agents, which is beneficial to the self-healing of scratches. It is also related to the glass transition temperature (Tg) of the material; a lower Tg is more conducive to the self-healing of scratches.

[0025] Specifically, the molecular weight of E-44 type epoxy resin is 450–460 g / mol. More specifically, the molecular weight of E-44 type epoxy resin is 455 g / mol.

[0026] In some embodiments, the catalyst used in step S2 is DMAP (N,N-dimethylaminopyridine).

[0027] In some embodiments, the amount of catalyst used in step S2 is 0.2 to 0.4 wt% of the prepolymer system, that is, the ratio of the amount of catalyst to the sum of the amounts of catalyst, vanillin, and epoxy resin is (0.2 to 0.4):100.

[0028] In some embodiments, the reaction in step S2 is carried out under mechanical stirring at a speed of 100 to 200 rpm.

[0029] In some embodiments, step S3 specifically involves: ultrasonically dispersing AGO in DMF (dimethylformamide) to obtain an AGO dispersion, adding the AGO dispersion to the prepolymer, mixing for 20-40 minutes, and then adding polyetheramine. After mixing evenly, a near-infrared fast-response precision self-healing anti-corrosion coating can be obtained.

[0030] In some embodiments, the mass ratio of AGO to prepolymer in step S3 is (0.4 to 1): 100. When the mass ratio of AGO to prepolymer is within the above range, the coating formed by curing the paint has superior self-healing properties.

[0031] In some embodiments, the mass ratio of polyetheramine to prepolymer in step S3 is (4.47–6.67):12.64. This ensures that the mass ratio of polyetheramine to prepolymer is within the aforementioned range, allowing the resulting coating to cure sufficiently to form a coating with good density. Specifically, the polyetheramine used in step S3 is T403 and / or D400 type polyetheramine, serving as a chain extender and curing agent. Compared to other polyetheramine-type curing agents, T403 type polyetheramine can cure the coating more thoroughly, and the increased degree of crosslinking can improve the tensile strength and other mechanical properties of the coating.

[0032] This invention also protects a near-infrared fast-response precision self-healing anti-corrosion coating prepared by the above preparation method.

[0033] This invention also protects a self-healing method for a near-infrared fast-response precision self-healing anti-corrosion coating, comprising the following steps:

[0034] A near-infrared fast-response precision self-healing anti-corrosion coating is used to create a coating. After the coating is damaged, it is placed in an environment with a power density of 1-2 W / cm². 2 Irradiate with near-infrared light for 3 to 30 minutes, and self-repair is completed after irradiation.

[0035] In some embodiments, the near-infrared fast response precision self-healing anti-corrosion coating is prepared by placing the near-infrared fast response precision self-healing anti-corrosion coating at a temperature of 140-180°C for 4-6 hours to cure. After curing, the coating is obtained.

[0036] In some embodiments, before curing, the following steps are included: drying the near-infrared fast-response precision self-healing anti-corrosion coating at a temperature of 60–100°C for 6–10 hours.

[0037] In some implementations, the wavelength of the near-infrared illumination is 970–985 nm, more specifically 978.3 nm.

[0038] In some implementations, the distance between the near-infrared light source and the near-infrared fast-response precision self-healing anti-corrosion coating is 1 to 2 cm.

[0039] Preferably, the irradiation time in the above self-healing method is 4 to 6 minutes.

[0040] The near-infrared fast-response precision self-healing anti-corrosion coating prepared by this invention has excellent photothermal conversion efficiency and self-healing performance. Therefore, it can achieve complete repair after damage after 4 to 6 minutes of near-infrared light irradiation and has the ability to heal quickly.

[0041] The present invention also provides a resin material containing dynamic chemical bonds, which is prepared by the following method: vanillin (Van), epoxy resin (E-44) and catalyst are reacted at 140℃-160℃ for 7-9h under mechanical stirring to obtain a prepolymer (E-Van); after cooling to 95℃-105℃, 20wt% DMF is added and stirred evenly, then polyetheramine (T403 and / or D400) is added and stirred evenly, and dried in an oven at 75-85℃ for 7-9h, and then cured at 150-180℃ for 4-6h to obtain the final product.

[0042] This resin material containing dynamic chemical bonds is synthesized by modifying E-44 with vanillin to form an aldehyde-terminated prepolymer, and using polyetheramines (T403, D400) as chain extenders and curing agents to form a resin system containing dynamic bonds. It can be used as a film-forming substance to prepare photoresponsive self-healing coatings or coatings.

[0043] In some embodiments, the resin material containing dynamic chemical bonds is prepared by the following method: vanillin, epoxy resin E-44, and catalyst are reacted at 150°C for 8 hours under mechanical stirring to obtain a prepolymer (E-Van); after cooling to 100°C, 20wt% DMF is added and stirred evenly, then polyetheramine (T403 and / or D400) is added and stirred evenly, poured into a polytetrafluoroethylene mold, placed in an oven at 80°C for 8 hours to dry, and then heated to 160°C for 5 hours to cure.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The coating provided by this invention can form bonds with vanillin. Therefore, AGO has good dispersibility and is not easy to agglomerate in the coating formed by the curing of the coating. This makes the coating have both excellent anti-corrosion ability and self-healing performance. Under near-infrared light irradiation, it can be completely repaired in less than 30 minutes. Moreover, the repaired coating has better anti-corrosion performance than the original coating. Attached Figure Description

[0046] Figure 1 The present invention provides a synthetic route for the near-infrared fast-response precision self-healing anti-corrosion coating.

[0047] Figure 2 The XPS maps of GO and AGO in step S1 of embodiment 3 of the present invention are shown.

[0048] Figure 3 The images show the FT-IR spectra of the coating formed by the curing of vanillin, E-44 type epoxy resin, prepolymer and coating obtained in Example 3 of this invention before and after hot pressing.

[0049] Figure 4The image shows the NMR spectrum of the coating formed by curing E-44 type epoxy resin and the obtained coating in Example 3 of this invention.

[0050] Figure 5 The stress-strain curves are shown for the coatings formed by curing the coatings obtained in Examples 1 to 5.

[0051] Figure 6 This is a test diagram of the hot-pressing recovery performance of the coating formed by curing the coating obtained in Example 1 of the present invention.

[0052] Figure 7 This is a test diagram of the self-healing performance of the coating formed by curing the coating obtained from the comparative experiment of the present invention.

[0053] Figure 8 This is a test graph showing the photothermal conversion efficiency of the coating formed by curing the coating obtained from the comparative experiment of the present invention.

[0054] Figure 9 The images show the electrochemical performance of the coatings formed by curing the coatings obtained from the comparative experiments of this invention in the initial state, after scratching, and after self-healing.

[0055] Figure 10 This is a stress-strain curve of the coating formed by curing the coating obtained in Example 1 of the present invention and its related comparative examples. Detailed Implementation

[0056] Unless otherwise specified, all chemical reagents used in the examples are commercially available. Among them, polyetheramine T403 is trimethylolpropane tripropylene glycol ether (amino-terminated), CAS: 39423-51-3; polyetheramine D-400 is α-(2-aminomethylethyl)-ω-(2-aminomethylethoxy)poly[oxy(methyl-1,2-ethylidene)], CAS: 9046-10-0.

[0057] Example 1

[0058] A method for preparing a near-infrared fast-response precision self-healing anti-corrosion coating, the synthesis route of which is as follows: Figure 1 As shown, it includes the following steps:

[0059] S1. GO and APTES were dispersed in ethanol by ultrasonic dispersion for 30 min. The mixture was then refluxed and stirred at 80 °C for 6 h. After the reaction was completed, 12 mL of water was slowly added under stirring to terminate the reaction. The mixture was centrifuged at 9000 rpm for 10 min, the precipitate was collected, washed three times with anhydrous ethanol, and dried thoroughly at 60 °C. After drying, it was ground to obtain AGO.

[0060] S2. Add 15.25g of vanillin, 22.70g of epoxy resin E-44, and 0.1264g of catalyst N,N-dimethylaminopyridine (DMAP) to a new three-necked flask, and react at 150℃ for 8 hours under mechanical stirring to obtain the prepolymer.

[0061] S3. Disperse 0.5wt% AGO ultrasonically in 7.0g of DMF, add the prepolymer synthesized in the previous step, continue stirring for 30min, then add 4.47g of polyetheramine T403 and stir evenly. Pour into a polytetrafluoroethylene mold, place in an 80℃ oven to dry for 8h, then heat to 160℃ to cure for 5h to obtain a near-infrared fast-response precision self-healing anti-corrosion coating, denoted as EVT100-GO. 0.5％ EVT100 indicates that the amount of T403 in the curing agent is 100%.

[0062] Example 2

[0063] A method for preparing a near-infrared fast-response precision self-healing anti-corrosion coating includes the following steps:

[0064] In a new three-necked flask, 15.25g of vanillin, 2.70g of epoxy resin E-442, and 0.1264g of catalyst DMAP were added and reacted at 150℃ for 8 hours under mechanical stirring to obtain a prepolymer. 0.5wt% AGO was ultrasonically dispersed in 7.0g of DMF, and the prepolymer synthesized in the previous step was added. Stirring was continued for 30 minutes, followed by the addition of 3.66g of polyetheramine T403 and 1.20g of D400, and the mixture was stirred until homogeneous. The mixture was poured into a polytetrafluoroethylene mold and dried in an oven at 80℃ for 8 hours. The temperature was then raised to 160℃ and cured for 5 hours to obtain a near-infrared fast-response precision self-healing anti-corrosion coating, designated EVT75-GO. 0.5％ EVT75 indicates that the amount of T403 in the curing agent is 75%.

[0065] The preparation method of AGO is the same as in Example 1.

[0066] Example 3

[0067] A method for preparing a near-infrared fast-response precision self-healing anti-corrosion coating includes the following steps:

[0068] Add 15.25g of vanillin, 22.70g of epoxy resin (E-44), and 0.1264g of DMAP catalyst to a new three-necked flask. React at 150℃ for 8 hours under mechanical stirring to obtain a prepolymer. Disperse 0.5wt% AGO ultrasonically in 7.0g of DMF, add the prepolymer synthesized in the previous step, and continue stirring for 30 minutes. Then add 2.69g of polyetheramine T403 and 2.66g of D400, stir until homogeneous, pour into a polytetrafluoroethylene mold, and dry in an oven at 80℃ for 8 hours. Then heat to 160℃ and cure for 5 hours to obtain a near-infrared fast-response precision self-healing anti-corrosion coating, denoted as EVT50-GO. 0.5％ EVT50 indicates that the amount of T403 in the curing agent is 50%.

[0069] The preparation method of AGO is the same as in Example 1.

[0070] The synthesized substances involved were characterized, and the XPS spectra of GO and AGO are shown below. Figure 2 As shown, compared with GO, the XPS full spectrum of AGO has three characteristic peaks from APTES at Si2p, Si2s, and N1s, confirming that APTES successfully modified the GO surface; the FT-IR spectra of the coatings formed by vanillin, E-44 epoxy resin, prepolymer, and the coating obtained in Example 3 after curing before and after hot pressing show that vanillin reacts with E-44 epoxy resin to form a coating with a peak density of 915 cm⁻¹. -1 The epoxy characteristic peak disappeared at 1646 cm⁻¹, and after adding polyetheramine and curing, the peak disappeared at 1646 cm⁻¹. -1 The presence of a characteristic peak of -C=N indicates the successful synthesis of the product; furthermore, the NMR spectra of the E-44 epoxy resin and the cured coating are as follows: Figure 4 As shown, the epoxy characteristic peaks disappeared after vanillin reacted with E-44 type epoxy resin, which also indicates the successful synthesis of the product.

[0071] Example 4

[0072] A method for preparing a near-infrared fast-response precision self-healing anti-corrosion coating includes the following steps:

[0073] In a new three-necked flask, 15.25g of vanillin, 22.70g of epoxy resin (E-44), and 0.1264g of DMAP catalyst were added and reacted at 150℃ for 8 hours under mechanical stirring to obtain a prepolymer. 0.5wt% AGO was ultrasonically dispersed in 7.0g of DMF, and the prepolymer synthesized in the previous step was added. Stirring was continued for 30 minutes, followed by the addition of 1.49g of polyetheramine T403 and 4.44g of D400, and the mixture was stirred until homogeneous. The mixture was poured into a polytetrafluoroethylene mold and dried in an oven at 80℃ for 8 hours. After curing at 160℃ for 5 hours, a near-infrared fast-response precision self-healing anti-corrosion coating, denoted as EVT25-GO, was obtained. 0.5％EVT25 indicates that the amount of T403 in the curing agent is 25%.

[0074] The preparation method of AGO is the same as in Example 1.

[0075] Example 5

[0076] A method for preparing a near-infrared fast-response precision self-healing anti-corrosion coating includes the following steps:

[0077] Add 15.25g of vanillin, 22.70g of epoxy resin (E-44), and 0.1264g of DMAP catalyst to a new three-necked flask. React at 150℃ for 8 hours under mechanical stirring to obtain a prepolymer. Disperse 0.5wt% AGO ultrasonically in 7.0g of DMF, add the prepolymer synthesized in the previous step, and continue stirring for 30 minutes. Then add 6.67g of polyetheramine D400 and stir until homogeneous. Pour the mixture into a polytetrafluoroethylene mold, dry in an oven at 80℃ for 8 hours, and then cure at 160℃ for 5 hours to obtain the final product, denoted as EVT0-GO. 0.5％ EVT0 indicates that the amount of T403 in the curing agent is 0.

[0078] The preparation method of AGO is the same as in Example 1.

[0079] To investigate the effect of different AGO addition amounts on the photothermal conversion of the resulting coating, the applicant conducted a comparative experiment, the specific methods of which are as follows:

[0080] In a new three-necked flask, 15.25 g of vanillin, 22.70 g of epoxy resin (E-44), and 0.1264 g of DMAP catalyst were added and reacted at 150 °C for 8 h under mechanical stirring to obtain a prepolymer. 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, and 1 wt% AGO were ultrasonically dispersed in 7.0 g of DMF, and the prepolymer synthesized in the previous step was added to each. Stirring was continued for 30 min, followed by the addition of 2.69 g of polyetheramine T403 and 2.66 g of D400, and stirred until homogeneous. The mixture was poured into a polytetrafluoroethylene mold, dried in an oven at 80 °C for 8 h, and then cured at 160 °C for 5 h to obtain a series of products, which were designated EVT50-GO according to their AGO content. 0.1％ EVT50-GO 0.2％ EVT50-GO 0.3％ EVT50-GO 0.4％ EVT50-GO 0.5％ EVT50-GO 1％ The preparation method of AGO is the same as in Example 1.

[0081] To investigate the effect of different reaction sequences on coating performance, the applicant also conducted a comparative experiment. Based on Example 1, vanillin was first reacted with a curing agent and then mixed with epoxy resin for curing (the resulting product is denoted as VTE-GO). The specific method is as follows:

[0082] The reaction conditions and parameters were the same as in the previous example, except that: after adding vanillin and polyetheramine T403 to a new three-necked flask, epoxy resin E-44 and catalyst DMAP were added, and the reaction was carried out at 150°C for 8 hours under mechanical stirring; 0.5 wt% AGO was ultrasonically dispersed in 7.0 g of DMF, and the resin synthesized in the previous step was added. The mixture was stirred for another 30 minutes, poured into a polytetrafluoroethylene mold, dried in an oven at 80°C for 8 hours, and then cured at 160°C for 5 hours to obtain the product, denoted as VTE100-GO. 0.5％ .

[0083] Next, relevant performance tests will be conducted on the various products obtained above.

[0084] I. Sample Preparation

[0085] The coatings obtained from the examples and series of comparative experiments were dried at 80°C for 8 hours, and then cured at 160°C for 5 hours. After curing, a near-infrared fast-response precision self-healing anti-corrosion coating was obtained. Then, according to the GB / T1040.2-2006 standard, the near-infrared fast-response precision self-healing anti-corrosion coating was prepared into test samples.

[0086] II. Performance Testing Methods

[0087] 1. Mechanical property testing: Using the products obtained in Examples 1-5 as samples, tensile tests were conducted on the test samples using a UTM5000 universal testing machine; the tensile speed was 5 mm / min. -1 The gauge length is 50 mm, and the average of three experiments is taken as the accurate value of tensile strength and elongation at break.

[0088] 2. Hot pressing recovery performance: The test sample was crushed and hot-pressed at 160℃ and 15MPa for 30 minutes using a hot press.

[0089] 3. Self-healing performance test: A portion of the products obtained from the comparative experiment were coated onto glass slides using a four-sided preparation apparatus and cured to form a coating. The coating was then scratched with a scratch pen and examined under a microscope using a power density of 1.4 W / cm². 2 The coating was irradiated with near-infrared light at a distance of 1.5cm, and the self-healing effect of the scratches was recorded.

[0090] 4. Photothermal conversion test: A near-infrared light emitter with a power density of 1.4 W / cm² was used. 2The coating was compared with a portion of the coating irradiated by near-infrared light at a distance of 1.5cm, and the coating temperature was recorded in real time using a thermal imager.

[0091] 5. Corrosion Resistance Test: Using EVT50-GO 0.5% as the sample, a coating was prepared by applying the coating to a carbon steel sample and then curing it. The corrosion resistance of the coating was characterized by the electrochemical properties of the carbon steel sample. The electrochemical behavior of the coated carbon steel sample, as well as the carbon steel sample with scratches and repairs, in 3.5wt% NaCl solution was studied using a CHI-660E electrochemical workstation.

[0092] III. Performance Test Results

[0093] 1. Mechanical property testing

[0094] Mechanical performance test data are shown in Table 1 and Figure 5 As shown in Table 1, selecting T403 type polyetheramine results in a coating with superior curing effect, thus leading to better physical properties. Figure 5 As shown, the tensile strength reaches a maximum of 80 MPa when the content of polyetheramine T403 is 100%, which is rare in previous reports. With increasing content of polyetheramine D400 in the resin system, the degree of crosslinking decreases, and the tensile strength decreases, but can still be maintained at a minimum of 25 MPa. This indicates that the present invention prefers T403 type polyetheramine because the resulting coating has superior mechanical properties.

[0095] Table 1. Mechanical property test data of the coatings obtained in Examples 1-5

[0096] Tensile strength / MPa Elongation at break / % Example 1 80.1 15.2 Example 2 70.2 15.0 Example 3 59.8 13.5 Example 4 50.5 17.5 Example 5 25.7 14.5

[0097] In addition, the product EVT100-GO from Example 1 will be used. 0.5％ Compared with the control experiment VTE100-GO 0.5％ The mechanical properties are evaluated, such as Figure 10 As shown, two parallel tests were conducted on the coating obtained in Comparative Example 1. The results showed that the mechanical properties of the coating obtained in Comparative Example 1 decreased. This is because after vanillin reacts with the curing agent and is then mixed and cured with epoxy resin, the aldehyde groups are consumed by the curing agent. Furthermore, due to steric hindrance, the amino groups on the AGO surface are difficult to condense with the aldehyde groups. Therefore, AGO and the coating matrix can only be physically blended. During curing, the graphene aggregates and settles, resulting in a decrease in performance, with the tensile strength decreasing by about 10 MPa. However, when the prepolymer is synthesized first, the amino groups on the surface of the reduced graphene oxide added before curing will undergo an amine-aldehyde condensation reaction with the aldehyde groups of the prepolymer. The resin system will be covalently grafted with the graphene, which is beneficial to improving the various properties of the composite material.

[0098] 2. Hot-pressing recovery performance

[0099] Test results are as follows Figure 6 As shown, the tablets are smooth and flat, exhibiting excellent recyclability.

[0100] 3. Self-healing performance test

[0101] The test results are shown in Table 2 and Figure 7 As shown in Table 2, with the increase of AGO content, the complete healing time of scratches in the coating provided by this invention is significantly accelerated, shortening from 30 minutes to 5 minutes, demonstrating excellent self-healing performance. Specifically, when the mass ratio of AGO to prepolymer is within the range of (0.4–1):100, the time for complete self-healing of the resulting coating is significantly reduced, exhibiting even better self-healing performance. Figure 7 It can be seen that as the graphene content increases, the time for complete scratch healing is significantly accelerated, shortening from 30 minutes to 5 minutes. When the graphene content reaches 1%, the scratch is completely healed in 5 minutes, demonstrating excellent self-healing performance.

[0102] Table 2. Self-healing and photothermal conversion properties of coatings obtained from a series of comparative experiments.

[0103] Scratch healing time / min Coating surface temperature after 2 minutes of light exposure / ℃ <![CDATA[EVT50-GO 0.1％ ]]> 30 (Scratches become smaller) 60.7℃ <![CDATA[EVT50-GO 0.2％ ]]> 20 (Scratches become smaller) 70.9℃ <![CDATA[EVT50-GO 0.3％ ]]> 20 (Scratches become smaller) 75.6℃ <![CDATA[EVT50-GO 0.4％ ]]> 5 (Complete Healing) 83.4℃ <![CDATA[EVT50-GO 0.5％ ]]> 5 (Complete Healing) 99.8℃ <![CDATA[EVT50-GO 1.0％ ]]> 5 (Complete Healing) 110.5℃

[0104] 4. Photothermal conversion test

[0105] The test results are shown in Table 2 and Figure 8 As shown, the photothermal conversion of the coating mainly occurs in the first 20 seconds. Within 20 seconds, the coating temperature rises rapidly. At 2 minutes, the heat absorption equals the heat release, and the temperature reaches its maximum value, which can reach 110℃. This demonstrates excellent photothermal conversion performance and provides a basis for the rapid self-healing of the coating.

[0106] 5. Electrochemical testing

[0107] Test results are as follows Figure 9 As shown, the initial EVT50-GO 0.5％ The coating has an impedance value of 5.28 × 10⁻⁶. 10 |Z| / Ω·cm 2 Furthermore, no new time constant was observed, indicating that the coating possesses excellent corrosion resistance. The impedance value of the coating after scratching is 8.5 × 10⁻⁶. 4 |Z| / Ω·cm 2 Furthermore, the appearance of a new time constant in the low-to-mid-frequency region indicates that the coating has been scratched through, and its anti-corrosion effect has completely failed. The impedance modulus of the scratch after complete healing under near-infrared light irradiation is 3.24 × 10⁻⁶. 10 |Z| / Ω·cm 2 The impedance value was 5 orders of magnitude higher than when the scratch occurred, and no new time constant appeared, indicating that the anti-corrosion performance of the coating on the surface was well restored.

[0108] The above descriptions are merely some embodiments of the present invention. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for preparing a near-infrared fast-response precise self-healing anti-corrosion coating, characterized in that, Includes the following steps: S1. GO is modified using an amino-containing modifier to obtain AGO after modification; S2. Vanillin, epoxy resin, and catalyst are mixed and reacted at a temperature of 100~200℃ for 6~10 h to obtain a prepolymer. The molar ratio of vanillin to epoxy resin is (1.5~2.5):

1. S3. The AGO obtained in step S1 is ultrasonically dispersed in DMF, and then mixed with the prepolymer obtained in step S2. After mixing, polyetheramine is added to react, and a near-infrared fast-response precision self-healing anti-corrosion coating can be obtained; the mass ratio of AGO to prepolymer is (0.1~1):

100.

2. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of polyetheramine to the prepolymer is (4.47~6.67):12.

64.

3. The preparation method according to claim 2, characterized in that, In step S3, the polyetheramine is T403 type polyetheramine and / or D400 type polyetheramine.

4. A near-infrared fast-response precision self-healing anti-corrosion coating prepared by the preparation method according to any one of claims 1 to 3.

5. The self-healing method of the near-infrared fast-response precise self-healing anti-corrosion coating as described in claim 4, characterized in that, Includes the following steps: A near-infrared fast-response precision self-healing anti-corrosion coating is used to create a coating. After the coating is damaged, it is placed in an environment with a power density of 1~2 W / cm². 2 Irradiate with near-infrared light for 3 to 30 minutes, and self-repair is completed after irradiation.

6. The self-healing method of the near-infrared fast-response precision self-healing anti-corrosion coating according to claim 5, characterized in that, The irradiation time is 4 to 6 minutes.

Images