A wear-repair self-sensing coating and a method of making the same

Abstract

The present application belongs to the technical field of functional coating preparation, and particularly relates to a wear-repair self-sensing coating and a preparation method thereof. The coating comprises a damage sensing component and a modified polymer resin; the damage sensing component is prepared by grafting diisocyanate and functionalized rhodamine on MXene nanosheets in sequence; and the modified polymer resin is an epoxy-terminated polyurea resin prepared by reacting a polyurea resin with a diglycidyl ether. The present application realizes real-time dynamic indication of the wear process. As a carrier, MXene nanosheets form a stable network structure by chemically grafting diisocyanate, and then combine with functionalized rhodamine, so that the coating releases a fluorescent signal when damaged. After the coating is worn, the damage position and the wear area can be quickly identified through fluorescence enhancement behavior, and at the same time, after the coating is damaged and repaired, the repair degree of the damage can be indicated through fluorescence weakening / quenching behavior, so as to realize dynamic visual sensing of the wear-repair process of the coating.

Description

Technical Field

[0001] This invention belongs to the field of functional coating preparation technology, specifically relating to a wear-repair self-sensing coating and its preparation method. Background Technology

[0002] In high-end equipment manufacturing, marine engineering, and shipping, critical components face wear failure caused by friction, debris impact, erosion from sediment, high wind speeds, or fluid flow, leading to serious safety hazards and significant economic losses. Applying polymer wear-resistant coatings to the surfaces of equipment components is an effective way to reduce frictional damage and prevent equipment wear failure. However, in harsh and complex service environments, polymer coatings inevitably develop micro-defects such as wear or localized damage. If these micro-defects are not detected and addressed in a timely manner, they will develop into macro-damage, further accelerating the wear process. This seriously threatens the integrity of the coating and shortens the service life of the equipment.

[0003] Early monitoring of coating wear and rapid repair of damage are essential for ensuring the safe and stable operation of equipment. Damage-sensing / self-early warning coatings can convert material wear damage into distinct color / fluorescent signals, providing crucial information about the location and extent of coating wear. Combining damage self-sensing / self-early warning with self-repair is an effective means of achieving visualized wear perception and repair. Currently, damage visualization and repair are mainly achieved through externally induced microcapsule rupture to release chromogenic agents and repair machines. However, coatings prepared using these strategies can only sense the occurrence of coating wear. Coating repair is a dynamic evolution process, accompanied by changes in damage scale and interface state. Traditional damage sensing strategies cannot respond in real time to the dynamic process of wear generation and repair, and cannot indicate damage repair efficiency and coating service status through visual signals.

[0004] Therefore, there is an urgent need to develop damage-sensing coatings that provide dynamic visualization of coating wear and repair processes in order to achieve accurate assessment of the coating's service status. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a wear-repair self-sensing coating and its preparation method. The coating is composed of damage sensing components and modified polymer resin. After the coating is worn, it can quickly identify the damage location and wear area through fluorescence enhancement behavior. At the same time, after the coating damage is repaired, it can indicate the degree of damage repair through fluorescence weakening / quenching behavior, so as to realize dynamic visualization of the coating wear-repair process.

[0006] The technical solution adopted is as follows:

[0007] A wear-repair self-sensing coating, the coating comprising a damage sensing component and a modified polymer resin; the damage sensing component is prepared by sequentially grafting diisocyanate and functionalized rhodamine onto MXene nanosheets; the modified polymer resin is an epoxy-terminated polyurea resin prepared by reacting polyurea resin with diglycidyl ether.

[0008] Preferably, the diisocyanate is any one of hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate; and the functionalized rhodamine is any one of aminorhodamine 6G and hydroxyrhodamine 6G.

[0009] Preferably, the diglycidyl ether is any one of ethylene glycol diglycidyl ether, butanediol diglycidyl ether, resorcinol diglycidyl ether, and bisphenol A diglycidyl ether; the polyurea resin is a linear polymer formed by the reaction of a diamine and a diisocyanate. The diamine is a mixture of isophorone diamine and polyetheramine D230 (molar ratio 2:1); the diisocyanate is a mixture of dicyclohexylmethane diisocyanate and lysine diisocyanate (molar ratio 1:1).

[0010] Preferably, the damage sensing component has a mass fraction of 1% to 10% in the modified polymer resin.

[0011] A method for preparing a wear-repair self-sensing coating includes the following steps:

[0012] (1) MXene nanosheets and diisocyanate were dissolved together in N,N-dimethylformamide solution, stirred evenly, and then an organotin catalyst was added. The mixture was heated and stirred to react, and then centrifuged to obtain the first reactant.

[0013] (2) The first reactant and functionalized rhodamine were dissolved together in N,N dimethylformamide solution, stirred evenly, heated, stirred and reacted, and centrifuged to obtain the damage sensing component;

[0014] (3) Dissolve diglycidyl ether and polyurea resin together in N,N dimethylformamide solution, stir evenly, heat and stir to react, and obtain modified polymer resin.

[0015] (4) Mix the damage sensing component with the modified polymer resin evenly, treat with ultrasound, and then spray it onto the surface of the metal substrate after standing. After standing at room temperature, cure the metal substrate in an oven to obtain the wear-repair self-sensing coating.

[0016] Preferably, in step (1), the mass ratio of MXene nanosheets to diisocyanate is 1:1 to 5; the organotin catalyst is 0.5% to 2% of the mass fraction of diisocyanate; the stirring temperature is 60℃ to 85℃, and the stirring time is 3h to 6h.

[0017] The organotin catalyst is dibutyltin dilaurate.

[0018] Preferably, the product after the reaction is centrifuged at a speed of 7000 r / min to 9000 r / min for 8 min to 10 min to obtain the first reactant.

[0019] Preferably, in step (2), the first reactant and functionalized rhodamine are reacted at a mass ratio of 1:0.1 to 0.5; the temperature of the stirring reaction is 40℃ to 60℃, and the reaction time is 3h to 6h; after the reaction, the mixture is centrifuged at a speed of 7000r / min to 9000r / min for 8min to 10min.

[0020] Preferably, in step (3), the mass ratio of diglycidyl ether to polyurea resin is 0.1 to 0.4:1; the stirring reaction temperature is 40°C to 60°C; and the stirring reaction time is 5 to 8 hours.

[0021] Preferably, in step (4), the ultrasonic treatment time is 5 min to 10 min, the standing time is 5 min to 10 min; the coating is sprayed onto the surface of the metal substrate at an air pressure of 0.2 MPa to 0.5 MPa, and after standing at room temperature for 20 min to 30 min, the metal substrate is cured in an oven at 50℃ to 70℃ for 12 h to 24 h.

[0022] The prepared wear-repair self-sensing coating has a dynamic wear-repair indication function. When the coating is worn, it can quickly identify the damage location and wear area through fluorescence enhancement behavior. At the same time, after the coating damage is repaired, it can indicate the degree of damage repair through fluorescence weakening / quenching behavior, realizing dynamic visualization perception of the coating wear-repair process.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1) Real-time dynamic indication of the wear process was achieved through the synergistic effect of MXene nanosheets and functionalized rhodamine. MXene nanosheets, acting as a carrier, formed a stable network structure through chemical grafting of diisocyanate, which then combined with functionalized rhodamine, causing the coating to release fluorescent signals when damaged. When mechanical damage occurs to the coating, the functionalized rhodamine reacts with metal ions (such as Fe)... 3+ By combining fluorescence changes, the damage location can be accurately pinpointed, enabling dynamic visualization and perception of the coating wear-repair process.

[0025] 2) The introduction of modified polyurea resin endows the coating with excellent self-healing ability. The dynamic chemical bonds (such as hydrogen bonds and ionic bonds) formed by the reaction of diglycidyl ether and polyurea resin can be re-crosslinked under heat or light, restoring structural integrity. In addition, the layered structure of MXene nanosheets can extend the diffusion path of corrosive media, forming a dual mechanism of "passive protection + active repair", which significantly extends the coating life.

[0026] 3) The synergistic effect of MXene nanosheets and polyurea resin gives the coating both high hardness and flexibility, improving mechanical properties. The surface functional groups of MXene (such as -OH, -O) promote interfacial bonding with the polymer, improving coating adhesion; while the dynamic chemical bonds of polyurea resin endow the coating with impact resistance.

[0027] 4) The self-sensing coating prepared by this invention has corrosion resistance and wear resistance, can quickly self-repair, the coating preparation method is simple, easy to scale up production, and has broad application prospects. Attached Figure Description

[0028] Figure 1 This is a scanning electron microscope image of the damage sensing component in Embodiment 1 of the present invention.

[0029] Figure 2 This is the infrared spectrum of the damage sensing component in Embodiment 1 of the present invention.

[0030] Figure 3 This is the infrared spectrum of the modified polymer resin in Example 1 of the present invention.

[0031] Figure 4 This is an infrared thermal imaging image of the wear-repair self-sensing coating in Embodiment 1 of the present invention.

[0032] Figure 5 This is a fluorescence photograph of the wear-repair self-sensing coating in Embodiment 1 of the present invention during the wear-repair process.

[0033] Figure 6 This is a friction and wear curve of the wear-repair self-sensing coating in Embodiment 2 of the present invention.

[0034] Figure 7 This is a surface contour diagram of the wear-repair self-sensing coating wear-repair process in Embodiment 2 of the present invention. Detailed Implementation

[0035] The accompanying drawings are for illustrative purposes only; it should be understood that the examples mentioned below are merely for explaining the invention, for describing the invention and simplifying the description, and therefore should not be construed as limiting the invention. Unless otherwise specified, the chemical materials used in this invention are all available through conventional commercial channels, and the MXene nanosheets used were purchased through conventional commercial channels. Unless otherwise specified, the tests performed can be obtained through conventional experimental methods.

[0036] In view of the existing problems in the field of wear-resistant protective coatings, the inventors of this application, through long-term research and extensive practice, have proposed the technical solution of this invention, which can realize dynamic visualization of the coating wear-repair process by synthesizing damage sensing and modified polymer resin.

[0037] The present invention will now be described in detail with reference to the accompanying drawings and embodiments, and the scope of protection of the present invention is not limited to the scope described in the following embodiments.

[0038] Example 1

[0039] A method for preparing a wear-repair self-sensing coating includes the following steps:

[0040] (1) Dissolve 1g of MXene nanosheets and 1g of hexamethylene diisocyanate in N,N-dimethylformamide, stir evenly, and then add 0.01g of organotin catalyst; stir at 80℃ for 4h, and then centrifuge at 8000r / min for 8min to obtain the first reactant;

[0041] (2) Dissolve 1g of the first reactant and 0.1g of aminorhodamine 6G together in N,N dimethylformamide solution, stir evenly, stir for 3h at 40℃, and centrifuge at 7000r / min for 8min to obtain the damage sensing component.

[0042] (3) Dissolve 0.1g of ethylene glycol diglycidyl ether and 1g of polyurea resin together in N,N dimethylformamide solution, stir evenly, and stir for 5h at 40℃ to obtain modified polymer resin.

[0043] (4) Mix 0.2g of damage sensing component with 10g of modified polymer resin evenly, ultrasonically treat for 5min, let stand for 5min, spray on the surface of metal substrate under air pressure of 0.3MPa, let stand at room temperature for 20min, and then cure in 50℃ oven for 15h to obtain a damage self-sensing coating with dynamic indication wear-repair function, namely the wear-repair self-sensing coating.

[0044] like Figure 1The scanning electron microscope image of the damage-sensing component shown reveals that the nanomaterial exhibits a sheet-like structure with a rough surface, and is approximately 40–50 μm in length; Figure 2 The infrared spectrum of the damage-sensing component in Example 1 clearly shows the characteristic Ti-C absorption peak (551 cm⁻¹) of the MXene nanosheets. -1 Rhodamine ring skeleton absorption peak (819 cm⁻¹) -1 ).like Figure 3 The infrared spectrum of the modified polymer resin in Example 1 clearly shows the presence of epoxy groups (919 cm⁻¹) in the modified resin. -1 ), hydroxyl (3340cm) -1 ) and urea carbonyl (1600~1750cm) -1 Characteristic absorption peaks. For example... Figure 4 The image shown is an infrared thermographic photograph of the damage-sensing coating in Example 1. It can be seen that after 15 seconds of infrared irradiation, the surface temperature of the coating rapidly rises to 73.4°C, indicating that the prepared coating possesses excellent photothermal conversion capabilities. Figure 5 The image shows a fluorescence photograph of the damage-sensing coating in Example 1 during the wear-repair process. It can be seen that the fluorescence is enhanced during wear, while it is weakened during the repair process.

[0045] Example 2

[0046] A method for preparing a wear-repair self-sensing coating differs from Example 1 in that 0.5g of damage sensing component is mixed evenly with 10g of modified polymer resin, ultrasonically treated for 5min, allowed to stand for 5min, and then sprayed onto the surface of a metal substrate under an air pressure of 0.3MPa. After standing at room temperature for 20min, it is cured in an oven at 50℃ for 15h to obtain a damage self-sensing coating with dynamic wear-repair indication function, namely the wear-repair self-sensing coating.

[0047] Other areas not mentioned are the same as in Example 1.

[0048] Figure 6 This is a friction and wear curve of the damage-sensing coating in Example 2. Figure 7 This is a surface profile diagram of the wear-repair process of the self-sensing coating in Example 2.

[0049] Example 3

[0050] A method for preparing a wear-repair self-sensing coating includes the following steps:

[0051] (1) Dissolve 1g of MXene nanosheets and 2g of isophorone diisocyanate in N,N-dimethylformamide, stir evenly, and then add 0.01g of organotin catalyst; stir at 80℃ for 4h, and then centrifuge at 8000r / min for 8min to obtain the first reactant;

[0052] (2) Dissolve 1g of the first reactant and 0.1g of aminorhodamine 6G together in N,N dimethylformamide solution, stir evenly, stir for 3h at 40℃, and centrifuge at 7000r / min for 8min to obtain the damage sensing component.

[0053] (3) Dissolve 0.1g of ethylene glycol diglycidyl ether and 1g of polyurea resin together in N,N dimethylformamide solution, stir evenly, and stir for 5h at 40℃ to obtain modified polymer resin.

[0054] (4) Mix 0.2g of damage sensing component with 10g of modified polymer resin evenly, ultrasonically treat for 5min, let stand for 5min, spray on the surface of metal substrate under air pressure of 0.3MPa, let stand at room temperature for 20min, and then cure in 50℃ oven for 15h to obtain a damage self-sensing coating with dynamic indication wear-repair function.

[0055] Example 4

[0056] (1) Dissolve 1g of MXene nanosheets and 1g of hexamethylene diisocyanate in N,N-dimethylformamide, stir evenly, and then add 0.01g of organotin catalyst; stir at 80℃ for 4h, and then centrifuge at 8000r / min for 8min to obtain the first reactant;

[0057] (2) Dissolve 1g of the first reactant and 0.2g of aminorhodamine 6G together in N,N dimethylformamide solution, stir evenly, stir for 3h at 40℃, and centrifuge at 7000r / min for 8min to obtain the damage sensing component.

[0058] (3) Dissolve 0.1g of ethylene glycol diglycidyl ether and 1g of polyurea resin together in N,N dimethylformamide solution, stir evenly, and stir for 5h at 40℃ to obtain modified polymer resin.

[0059] (4) Mix 0.2g of damage sensing component with 10g of modified polymer resin evenly, ultrasonically treat for 5min, let stand for 5min, spray on the surface of metal substrate under air pressure of 0.3MPa, let stand at room temperature for 20min, and then cure in 50℃ oven for 15h to obtain a damage self-sensing coating with dynamic indication wear-repair function.

[0060] Example 5

[0061] (1) Dissolve 1g of MXene nanosheets and 1g of hexamethylene diisocyanate in N,N-dimethylformamide, stir evenly, and then add 0.01g of organotin catalyst; stir at 80℃ for 4h, and then centrifuge at 8000r / min for 8min to obtain the first reactant;

[0062] (2) Dissolve 1g of the first reactant and 0.2g of aminorhodamine 6G together in N,N dimethylformamide solution, stir evenly, stir for 3h at 40℃, and centrifuge at 7000r / min for 8min to obtain the damage sensing component.

[0063] (3) Dissolve 0.3g of bisphenol A diglycidyl ether and 1g of polyurea resin together in N,N dimethylformamide solution, stir evenly, and stir for 5h at 40℃ to obtain modified polymer resin.

[0064] (4) Mix 0.2g of damage sensing component with 10g of modified polymer resin evenly, ultrasonically treat for 5min, let stand for 5min, spray on the surface of metal substrate under air pressure of 0.3MPa, let stand at room temperature for 20min, and then cure in 50℃ oven for 15h to obtain a damage self-sensing coating with dynamic indication wear-repair function.

[0065] Comparative Example 1

[0066] (1) Dissolve 1g of MXene nanosheets and 1g of hexamethylene diisocyanate in N,N-dimethylformamide, stir evenly, and then add 0.01g of organotin catalyst; stir at 80℃ for 4h, and then centrifuge at 8000r / min for 8min to obtain the first reactant;

[0067] (2) Dissolve 0.1g of ethylene glycol diglycidyl ether and 1g of polyurea resin together in N,N dimethylformamide solution, stir evenly, and stir for 5h at 40℃ to obtain modified polymer resin.

[0068] (3) Mix 0.2g of the first reactant with 10g of modified polymer resin evenly, ultrasonically treat for 5min, let stand for 5min, spray on the surface of the metal substrate under an air pressure of 0.3MPa, let stand at room temperature for 20min, and then cure in an oven at 50℃ for 15h to obtain the coating.

[0069] Comparative Example 2

[0070] (1) Dissolve 0.1g of ethylene glycol diglycidyl ether and 1g of polyurea resin together in N,N dimethylformamide solution, stir evenly and stir for 5h at 40℃ to obtain modified polymer resin.

[0071] (2) 10g of modified polymer resin was ultrasonically treated for 5min, left to stand for 5min, and then sprayed onto the surface of the metal substrate under an air pressure of 0.3MPa. After standing at room temperature for 20min, it was cured in an oven at 50℃ for 15h to obtain the coating.

[0072] The coatings prepared in Examples 1-5 and the coatings in Comparative Examples 1 and 2 were subjected to mechanical property tests, and the results are shown in Table 1.

[0073] Table 1. Comparison of mechanical properties of coatings prepared in Examples 1-5 with those in Comparative Examples 1 and 2.

[0074] Tensile strength (MPa) Elongation at break (%) <![CDATA[Toughness (MJ / m 3 )]]> Adhesion (MPa) Example 1 25.1 650 120.5 8.1 Example 2 31.5 460 112.3 8.5 Example 3 28.4 600 130.5 9.0 Example 4 29.5 670 138.9 9.5 Example 5 32.2 630 142.5 10.6 Comparative Example 1 16.8 780 71.6 6.8 Comparative Example 2 9.5 810 58.7 5.2

[0075] As shown in Table 1, the wear-repair self-sensing coatings prepared in Examples 1-5 of the present invention have significantly improved tensile strength and toughness compared with the coatings of Comparative Examples 1 and 2, and their adhesion is also significantly improved.

[0076] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for preparing a wear-repair self-sensing coating, characterized in that, The coating comprises a damage-sensing component and a modified polymer resin; the damage-sensing component is prepared by sequentially grafting diisocyanate and functionalized rhodamine onto MXene nanosheets; the modified polymer resin is an epoxy-terminated polyurea resin prepared by reacting polyurea resin with diglycidyl ether; the mass fraction of the damage-sensing component in the modified polymer resin is 1% to 10%. The preparation method includes the following steps: (1) MXene nanosheets and diisocyanate were dissolved together in N,N-dimethylformamide, stirred evenly, and then an organotin catalyst was added. The mixture was heated and stirred, and then centrifuged to obtain the first reactant. (2) The first reactant and functionalized rhodamine were dissolved together in N,N dimethylformamide, stirred evenly, heated, stirred and reacted, and centrifuged to obtain the damage sensing component; (3) Dissolve diglycidyl ether and polyurea resin together in N,N-dimethylformamide, stir evenly, heat and stir to react, and obtain modified polymer resin. (4) Mix the damage sensing component with the modified polymer resin evenly, treat with ultrasound, and then spray it onto the surface of the metal substrate after standing. After standing at room temperature, cure the metal substrate in an oven to obtain the wear-repair self-sensing coating. The functionalized rhodamine is either aminorhodamine 6G or hydroxyrhodamine 6G. The ultrasonic treatment time is 5 min to 10 min, and the standing time is 5 min to 10 min; the coating is sprayed onto the surface of the metal substrate under an air pressure of 0.2 MPa to 0.5 MPa, and after standing at room temperature for 20 min to 30 min, the metal substrate is cured in an oven at 50℃ to 70℃ for 12 h to 24 h. The prepared wear-repair self-sensing coating has a dynamic wear-repair indication function. When the coating is worn, it can quickly identify the damage location and wear area through fluorescence enhancement behavior. At the same time, after the coating damage is repaired, it can indicate the degree of damage repair through fluorescence weakening / quenching behavior, realizing dynamic visualization perception of the coating wear-repair process.

2. The method for preparing a wear-repair self-sensing coating according to claim 1, characterized in that, The diisocyanate is any one of hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate.

3. The method for preparing a wear-repair self-sensing coating according to claim 1, characterized in that, The diglycidyl ether is any one of ethylene glycol diglycidyl ether, butanediol diglycidyl ether, resorcinol diglycidyl ether, and bisphenol A diglycidyl ether; the polyurea resin is a linear polymer generated by the reaction of a diamine and a diisocyanate, wherein the diamine is a mixture of isophorone diamine and polyetheramine D230; and the diisocyanate is a mixture of dicyclohexylmethane diisocyanate and lysine diisocyanate.

4. The method for preparing a wear-repair self-sensing coating according to claim 1, characterized in that, In step (1), the mass ratio of MXene nanosheets to diisocyanate is 1:1 to 5; the amount of organotin catalyst is 0.5% to 2% of the mass fraction of diisocyanate; the temperature for heating and stirring is 60℃ to 85℃, and the stirring time is 3h to 6h.

5. The method for preparing a wear-repair self-sensing coating according to claim 4, characterized in that, The product after the reaction was centrifuged at a speed of 7000 r / min to 9000 r / min for 8 min to 10 min to obtain the first reactant.

6. The method for preparing a wear-repair self-sensing coating according to claim 1, characterized in that, In step (2), the mass ratio of the first reactant to functionalized rhodamine is 1:0.1 to 0.5; the stirring temperature is 40℃ to 60℃, and the reaction time is 3h to 6h; after the reaction, the mixture is centrifuged at a speed of 7000r / min to 9000r / min for 8min to 10min.

7. The method for preparing a wear-repair self-sensing coating according to claim 1, characterized in that, In step (3), the mass ratio of diglycidyl ether to polyurea resin is 0.1 to 0.4:1; the stirring reaction temperature is 40°C to 60°C; and the stirring reaction time is 5 to 8 hours.

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