Self-repairing polyurethane coating and preparation method thereof
By preparing self-healing polyurethane coatings containing furandiol and maleimide functionalized carbon nanotubes, the problem of insufficient mechanical performance of traditional self-healing materials at room temperature is solved, and multiple self-healing and mechanical performance improvements are achieved, especially effectively repairing and enhancing the stability of the material under mild conditions.
Patent Information
- Application Number
- CN202510766652.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-10
- Publication Date
- 2025-08-19
AI Technical Summary
Traditional self-healing polyurethane materials have insufficient mechanical properties at room temperature, so they cannot achieve multiple effective self-repairs. The use of self-healing materials based on D-A reaction at high temperatures will lead to reduced mechanical properties.
Prepolymers were prepared using polycaprolactone diol, diphenylmethane diisocyanate and dibutyltin dilaurate, and functionalized carbon nanotubes of furandiol and maleimide were added. The self-healing polyurethane coating was formed through the Diels-Alder click reaction, and the mechanical properties were enhanced by gentle DA reaction conditions and the bridge of the carbon nanotubes.
The self-healing polyurethane coating has been realized for multiple self-healing capabilities at room temperature, and has significantly improved mechanical properties and stability. The introduction of carbon nanotubes has improved the interface bonding and the flexibility of the material, hindered crack propagation, and improved the durability of the material.
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Figure CN120505031A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to a self-repairing polyurethane coating and a preparation method thereof, belonging to the technical field of coatings. Background Art
[0002] Self-healing polyurethane is an important functional polyurethane material that can detect microcracks and self-repair them through the reversible reactions of the polyurethane molecular segments. Traditional self-healing materials mostly use external-aid self-repair methods. When the material is damaged or destroyed, the repair fluid flows from the microcapsules or hollow fibers to the damaged area. The repair fluid interacts with the corresponding components in the base material to achieve the purpose of self-healing of the damaged area. However, external-aid self-repair cannot effectively repair the same damaged area repeatedly. The reaction of the repair fluid under the action of the catalyst does not stop due to the healing of the damaged area. It will continue to react until one side is completely consumed, making it impossible to complete multiple repairs to the same part of the material.
[0003] Compared to external self-repairing that requires embedding repair agents inside the polymer, intrinsic self-repairing introduces special valence bonds into the molecular chain of the material. During repair, the damaged parts need to be in contact with each other. Based on the breaking and recombination of special chemical bonds, molecular-level self-healing is carried out through reversible chemical interactions between interfaces. This polymer prepared based on the intrinsic self-repairing mechanism can complete multiple effective healing of the same damaged part. Currently, self-repairing materials based on the DA (Diels-Alder) reaction have attracted much attention. However, due to the high reaction temperature required for the reverse DA reaction, the self-repairing polyurethane material prepared according to the DA reaction mechanism needs to be at a high temperature to complete efficient self-repair. However, in daily life, the material is used at room temperature, and increasing the temperature will cause the mechanical properties of the material to decrease. When this polymer material is used to assume a structural support role, the reduction in the mechanical properties of the material will cause irreparable damage. Summary of the Invention
[0004] In order to solve the above problems, a self-healing polyurethane coating and a preparation method thereof are provided, which can not only achieve self-repair of the coating film but also exhibit excellent mechanical properties, and has great application prospects in the field of coatings.
[0005] The technical solution of the present invention is:
[0006] According to one aspect of the present application, a method for preparing a self-repairing polyurethane coating is provided, comprising the following steps:
[0007] (1) adding polycaprolactone diol, diphenylmethane diisocyanate and an organic solvent into a reaction vessel filled with an inert gas, stirring and dissolving them, then adding dibutyltin dilaurate and reacting at 50-70° C. for 2-4 hours to obtain a prepolymer;
[0008] (2) adding furandiol to the prepolymer and reacting at 50-70° C. for 4-6 h. After the mixture is cooled to room temperature, pouring it into a Teflon petri dish to form a film, and then placing the film in a vacuum oven at 50-70° C. to dry for 1-3 days;
[0009] (3) The dried film is dissolved in an organic solvent, maleimide-functionalized carbon nanotubes are added, and the mixture is heated to 60-80°C in an inert atmosphere. The mixture is stirred and reacted for 20-30 hours to obtain a self-healing polyurethane coating.
[0010] Optionally, in step (1), the weight ratio of the polycaprolactone diol to diphenylmethane diisocyanate is (2-3):1.
[0011] Optionally, in step (1), the added amount of dibutyltin dilaurate is 0.08-0.12 wt % of the polycaprolactone diol.
[0012] Optionally, in step (2), the addition amount of the furan diol is 30-35wt% of the polycaprolactone diol.
[0013] Optionally, in step (3), the weight ratio of the dried film to the maleimide-functionalized carbon nanotubes is 1:(0.05-0.2).
[0014] Optionally, in step (3), the method for preparing maleimide-functionalized carbon nanotubes comprises the following steps:
[0015] S1. Adding amino carbon nanotubes and furan-2,5-dione to an organic solvent, ultrasonically dispersing for 5-15 minutes, then introducing an inert atmosphere, heating under reflux at 120-150° C. for 2-4 hours, and cooling to room temperature to obtain a mixture;
[0016] S2. Sodium acetate and acetic anhydride are added to the mixture, an inert atmosphere is introduced, the mixture is heated at 120-150° C. for 0.5-1.5 h, cooled to room temperature, centrifuged, the lower layer residue is collected, washed, and dried to obtain maleimide-functionalized carbon nanotubes.
[0017] Optionally, in step S1, the amount of the amino carbon nanotubes added is 18-25 wt % of furan-2,5-dione.
[0018] Optionally, in step S2, the amount of sodium acetate and acetic anhydride added is 6-8 wt % of furan-2,5-dione.
[0019] Optionally, the organic solvent is tetrahydrofuran, N-methylpyrrolidone, N,N-dimethylformamide, 1,2-dichlorobenzene or dimethyl sulfoxide.
[0020] According to another aspect of the present application, a self-healing polyurethane coating is provided, which is prepared using any of the above-mentioned methods for preparing the self-healing polyurethane coating.
[0021] In this application, "room temperature" refers to 20-30°C.
[0022] The beneficial effects of this application include but are not limited to:
[0023] 1. The self-healing polyurethane coating and preparation method of the present application grafts a polyurethane containing furan groups onto carbon nanotubes with maleimide through a Diels-Alder click reaction. The resulting material not only has excellent self-healing properties, but also has significantly improved mechanical properties. The DA reaction conditions based on the furan-maleimide system are relatively mild, and the DA reaction exhibits high reactivity. The formation of DA bonds can induce the formation of a strong cross-linked network within the material system. Heating treatment can easily induce DA bond breakage, giving the system good fluidity, which is conducive to the reorganization of chemical bonds at the cracks, and then reforming the cross-linked structure through the cooling process, thereby restoring the original strength of the material. The introduced carbon nanotubes have a bridging effect, which can transfer stress from the matrix to the carbon nanotubes, hindering the expansion of cracks, thereby enhancing the mechanical properties and stability of the material.
[0024] 2. The self-healing polyurethane coating and preparation method of the present application anchor maleimide groups in the carbon nanotube structure, improve the interfacial bonding between the carbon nanotubes and the polymer matrix, so that the carbon nanotubes show good dispersion in the composite material and can fully exert their reinforcing effect; this method of binding through covalent bonds is more stable than physical adsorption, and can effectively improve the interfacial compatibility and mechanical properties of the material; among them, polycaprolactone diol gives the material good flexibility and ductility, the introduction of carbon nanotubes enhances the mechanical strength of the dynamic network, and can cooperate with the dynamic network to achieve rapid heat conduction and crack propagation obstruction in the damaged area, that is, it not only accelerates the repair response, but also acts as a physical barrier to avoid excessive softening or deformation of the material during the repair process, thereby improving its durability. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:
[0026] Figure 1 This is a scratch image of Example 2 of the present application before self-repair;
[0027] Figure 2 This is a scratch image of Example 2 of the present application after self-repair. DETAILED DESCRIPTION
[0028] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.
[0029] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. The raw materials or instruments used, if the manufacturers are not specified, are all conventional products that can be purchased commercially.
[0030] The amino carbon nanotubes involved in the following examples and comparative examples have a diameter of 20-40 nm and were purchased from Shanghai MacLean Biochemical Technology Co., Ltd.
[0031] Example 1
[0032] A method for preparing a self-repairing polyurethane coating comprises the following steps:
[0033] (1) adding polycaprolactone diol and diphenylmethane diisocyanate in a weight ratio of 2:1 into a reaction vessel containing tetrahydrofuran, passing nitrogen, stirring to dissolve, and then adding dibutyltin dilaurate (0.08 wt % of polycaprolactone diol) and reacting at 50° C. for 2 h to obtain a prepolymer;
[0034] (2) adding 30 wt % of furan diol of polycaprolactone diol to the prepolymer, reacting at 50° C. for 4 h, and after the mixture was cooled to room temperature, pouring it into a Teflon petri dish to form a film, and then placing the film in a vacuum oven at 50° C. to dry for 1 day;
[0035] (3) The dried film was dissolved in N-methylpyrrolidone, and maleimide-functionalized carbon nanotubes were added, with the weight ratio of the dried film to the maleimide-functionalized carbon nanotubes being 1:0.05. The film was heated to 60°C in a nitrogen atmosphere, and stirred for 20 hours to obtain a self-healing polyurethane coating.
[0036] The method for preparing maleimide-functionalized carbon nanotubes comprises the following steps:
[0037] S1. Add furan-2,5-dione and amino carbon nanotubes containing 18 wt% of furan-2,5-dione to dimethyl sulfoxide, disperse them by ultrasonication for 5 minutes, then introduce nitrogen atmosphere, heat under reflux at 120° C. for 2 hours, and cool to room temperature to obtain a mixture;
[0038] S2. Add 1.2 wt% of furan-2,5-dione sodium acetate and 4.8 wt% of furan-2,5-dione acetic anhydride to the mixture, introduce nitrogen atmosphere, heat at 120°C for 0.5 h, cool to room temperature, centrifuge, collect the lower residue, wash, and dry to obtain maleimide-functionalized carbon nanotubes.
[0039] Example 2
[0040] A method for preparing a self-repairing polyurethane coating comprises the following steps:
[0041] (1) adding polycaprolactone diol and diphenylmethane diisocyanate in a weight ratio of 2.5:1 into a reaction vessel containing tetrahydrofuran, passing nitrogen, stirring to dissolve, and then adding dibutyltin dilaurate (0.1 wt % of polycaprolactone diol) and reacting at 60° C. for 3 h to obtain a prepolymer;
[0042] (2) adding 32 wt % of furan diol of polycaprolactone diol to the prepolymer, reacting at 60° C. for 5 h, and after the mixture was cooled to room temperature, pouring it into a Teflon petri dish to form a film, and then placing the film in a vacuum oven at 60° C. to dry for 2 d;
[0043] (3) The dried film was dissolved in N,N-dimethylformamide, and maleimide-functionalized carbon nanotubes were added. The weight ratio of the dried film to the maleimide-functionalized carbon nanotubes was 1:0.12. The film was heated to 70°C in a nitrogen atmosphere and stirred for 24 hours to obtain a self-healing polyurethane coating.
[0044] The method for preparing maleimide-functionalized carbon nanotubes comprises the following steps:
[0045] S1. Add furan-2,5-dione and amino carbon nanotubes containing 22 wt% of furan-2,5-dione to 1,2-dichlorobenzene, disperse under ultrasonication for 10 min, then introduce nitrogen atmosphere, heat under reflux at 130° C. for 3 h, and cool to room temperature to obtain a mixture;
[0046] S2. Add 1.4 wt% of furan-2,5-dione sodium acetate and 5.6 wt% of furan-2,5-dione acetic anhydride to the mixture, introduce nitrogen atmosphere, heat at 130°C for 1 hour, cool to room temperature, centrifuge, collect the lower residue, wash, and dry to obtain maleimide-functionalized carbon nanotubes.
[0047] Example 3
[0048] A method for preparing a self-repairing polyurethane coating comprises the following steps:
[0049] (1) adding polycaprolactone diol and diphenylmethane diisocyanate in a weight ratio of 3:1 into a reaction vessel containing tetrahydrofuran, passing nitrogen, stirring to dissolve, and then adding dibutyltin dilaurate (0.12 wt % of polycaprolactone diol) and reacting at 70° C. for 4 h to obtain a prepolymer;
[0050] (2) adding 35 wt % of furan diol of polycaprolactone diol to the prepolymer, reacting at 70° C. for 6 h, and after the mixture was cooled to room temperature, pouring it into a Teflon petri dish to form a film, and then drying the film in a vacuum oven at 70° C. for 3 d;
[0051] (3) The dried film was dissolved in N-methylpyrrolidone, and maleimide-functionalized carbon nanotubes were added, with the weight ratio of the dried film to the maleimide-functionalized carbon nanotubes being 1:0.2. The film was heated to 80°C in a nitrogen atmosphere, and stirred for 30 hours to obtain a self-healing polyurethane coating.
[0052] The method for preparing maleimide-functionalized carbon nanotubes comprises the following steps:
[0053] S1. adding furan-2,5-dione and amino carbon nanotubes containing 25 wt% of furan-2,5-dione to 1,2-dichlorobenzene, ultrasonically dispersing the mixture for 15 minutes, then introducing a nitrogen atmosphere, heating under reflux at 150° C. for 4 hours, and cooling to room temperature to obtain a mixture;
[0054] S2. Add 1.6 wt% of furan-2,5-dione sodium acetate and 6.4 wt% of furan-2,5-dione acetic anhydride to the mixture, introduce nitrogen atmosphere, heat at 150°C for 1.5 hours, cool to room temperature, centrifuge, collect the lower residue, wash, and dry to obtain maleimide-functionalized carbon nanotubes.
[0055] Comparative Example 1
[0056] The difference from Example 2 is that:
[0057] The maleimide-functionalized carbon nanotubes are replaced with bismaleimide, but the preparation method of the maleimide-functionalized carbon nanotubes is not disclosed.
[0058] Comparative Example 2
[0059] The difference from Example 2 is that the preparation method of maleimide-functionalized carbon nanotubes is not disclosed, and step (3) is:
[0060] The dried film was dissolved in N,N-dimethylformamide, and bismaleimide was added. The weight ratio of the dried film to bismaleimide was 1:0.12. The film was heated to 70°C in a nitrogen atmosphere and stirred for 24 hours. Then, carbon nanotubes containing 22wt% of bismaleimide were added and uniformly dispersed to obtain a self-healing polyurethane coating.
[0061] Comparative Example 3
[0062] The difference from Example 2 is that in step (3), the weight ratio of the dried film to the maleimide-functionalized carbon nanotubes is 1:0.01.
[0063] Comparative Example 4
[0064] The difference from Example 2 is that in step S1, the amount of amino carbon nanotubes added is 30 wt % of furan-2,5-dione.
[0065] The self-healing polyurethane coatings obtained by the methods of Examples 1-3 and Comparative Examples 1-4 were poured into polytetrafluoroethylene molds, placed at room temperature for 1 week, and then placed in an oven at 50°C for 12 hours. After demolding, a dry film with a thickness of about 1 mm was obtained.
[0066] The above film was subjected to a tensile test using a material testing machine, and the tensile strength and elongation at break were recorded. A 0.1 mm deep scratch was made on the film using a knife, and the film was repaired at 80°C for 5 hours before being subjected to another tensile test. The self-repair degree of the tensile strength and the self-repair degree of the elongation at break were calculated. The results are shown in Table 1 below.
[0067] Table 1
[0068]
[0069]
[0070] As can be seen from the results in Table 1, the self-repairing polyurethane coating prepared by the preparation method of the self-repairing polyurethane coating in this application exhibits excellent self-repairing properties and mechanical properties after film formation.
[0071] The self-healing behavior of the damaged film was observed by optical microscopy. Figure 1 To make a 0.1 mm deep scratch on the film of Example 2 using a knife, Figure 2 It can be seen that after 5 hours of self-repair at 80° C., the scratches on the film of Example 2 almost completely disappeared and were difficult to distinguish under an optical microscope.
[0072] The foregoing is merely an embodiment of the present application, and the scope of protection of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the technical ideas and principles of the present application should be included in the scope of protection of the present application.
Claims
1. A method for preparing a self-repairing polyurethane coating, characterized in that: The following steps are involved: (1) adding polycaprolactone diol, diphenylmethane diisocyanate and an organic solvent into a reaction vessel filled with an inert gas, stirring and dissolving them, then adding dibutyltin dilaurate and reacting at 50-70° C. for 2-4 hours to obtain a prepolymer; (2) adding furandiol to the prepolymer and reacting at 50-70° C. for 4-6 h. After the mixture is cooled to room temperature, pouring it into a Teflon petri dish to form a film, and then placing the film in a vacuum oven at 50-70° C. to dry for 1-3 days; (3) The dried film is dissolved in an organic solvent, maleimide-functionalized carbon nanotubes are added, and the mixture is heated to 60-80°C in an inert atmosphere. The mixture is stirred and reacted for 20-30 hours to obtain a self-healing polyurethane coating.
2. The method for preparing the self-repairing polyurethane coating according to claim 1, characterized in that: In step (1), the weight ratio of the polycaprolactone diol to diphenylmethane diisocyanate is (2-3):
1.
3. The method for preparing the self-repairing polyurethane coating according to claim 1, characterized in that: In step (1), the added amount of dibutyltin dilaurate is 0.08-0.12 wt % of the polycaprolactone diol.
4. The method for preparing the self-repairing polyurethane coating according to claim 1, characterized in that: In step (2), the addition of described furan diol is 30-35wt% of polycaprolactone diol.
5. The method for preparing the self-repairing polyurethane coating according to claim 1, characterized in that: In step (3), the weight ratio of the dried film to the maleimide-functionalized carbon nanotubes is 1:(0.05-0.2).
6. The method for preparing the self-repairing polyurethane coating according to claim 1, characterized in that: In step (3), the method for preparing maleimide-functionalized carbon nanotubes comprises the following steps: S1. Adding amino carbon nanotubes and furan-2,5-dione to an organic solvent, ultrasonically dispersing for 5-15 minutes, then introducing an inert atmosphere, heating under reflux at 120-150° C. for 2-4 hours, and cooling to room temperature to obtain a mixture; S2. Sodium acetate and acetic anhydride are added to the mixture, an inert atmosphere is introduced, the mixture is heated at 120-150° C. for 0.5-1.5 h, cooled to room temperature, centrifuged, the lower layer residue is collected, washed, and dried to obtain maleimide-functionalized carbon nanotubes.
7. The method for preparing the self-repairing polyurethane coating according to claim 6, characterized in that: In step S1, the amount of the amino carbon nanotubes added is 18-25 wt % of furan-2,5-dione.
8. The method for preparing the self-repairing polyurethane coating according to claim 6, characterized in that: In step S2, the amount of sodium acetate and acetic anhydride added is 6-8 wt % of furan-2,5-dione.
9. The method for preparing the self-repairing polyurethane coating according to claim 6, characterized in that: The organic solvent is tetrahydrofuran, N-methylpyrrolidone, N,N-dimethylformamide, 1,2-dichlorobenzene or dimethyl sulfoxide.
10. A self-repairing polyurethane coating, characterized in that: The self-repairing polyurethane coating is prepared by the preparation method of any one of claims 1 to 9.