A method for preparing a self-reinforced self-healing polyurethane film suitable for marine extreme environments
By utilizing polyurethane with blending force response and metal ion coordination function, polyurethane films can achieve spontaneous self-repair and self-reinforcement under mechanical force, solving the problem of material damage in extreme marine environments and improving the service life and crack propagation prevention capability of materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING UNIV OF CHEM TECH
- Filing Date
- 2024-07-05
- Publication Date
- 2026-07-03
AI Technical Summary
Existing polyurethane materials are difficult to self-repair after mechanical damage in extreme marine environments, resulting in a decline in material mechanical properties and a shortened service life. In particular, cracks are prone to propagate under high pressure, leading to instrument damage.
By preparing polyurethanes with force-responsive functions and polyurethanes with metal ion coordination functions, the coordination of iron ions with carboxyl or catechol groups is triggered by mechanical force to achieve self-crosslinking reaction, thereby realizing self-repair and self-reinforcement.
Under mechanical force, the material can self-repair, prevent crack propagation, and improve mechanical properties, making it suitable for marine extreme environmental protection materials.
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Figure CN118878877B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of self-healing materials and relates to a method for preparing a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments. Background Technology
[0002] Polyurethane elastomers are polymeric materials formed by the condensation reaction of polyols and polyisocyanates. They possess excellent mechanical properties and processability, and have been widely used in construction, aerospace, shipbuilding, transportation, medicine, and electronics. However, during service, polyurethane elastomers are susceptible to damage under external mechanical forces, leading to decreased mechanical properties and shortened service life. Imparting self-healing capabilities to polyurethane elastomers can effectively extend their service life and reduce safety risks. Currently developed self-healing polyurethane materials can be divided into two categories: intrinsic self-healing and extrinsic self-healing. Intrinsic self-healing materials contain reversible bonds in their molecular structure, enabling them to undergo multiple repairs under external conditions (such as light, heat, electricity, pH, etc.). For example, Chinese patent (CN115819703A) discloses a water-based room-temperature self-healing polyurethane based on double tellurium bonds and twisted multiple hydrogen bonds, which can achieve repair of large-scale material damage under visible light stimulation. Chinese patent (CN116410439A) discloses a self-healing polyurethane capable of repairing internal cracks under sunlight stimulation, its preparation method, and its application. This polyurethane can complete self-repair under sunlight irradiation. Chinese patent (CN117447669A) discloses a near-infrared light-responsive self-healing polyurethane elastomer, its preparation, and its application, enabling rapid and precise self-repair under near-infrared light conditions. With further industry development, developing materials capable of spontaneous self-healing without human intervention, similar to living tissue, has become a new challenge in the field. The ocean covers more than 70% of the Earth's surface, possessing unique organisms, vast geological features, and abundant mineral resources. However, under the extreme hydrostatic pressure of the deep ocean, rigid submersibles or probes are prone to cracking or breakage, which rapidly propagates under high pressure, leading to complete instrument destruction. Therefore, developing materials capable of rapid self-healing under high-pressure seawater environments is a significant challenge for the industry.
[0003] This invention first prepares a mechanoresponsive polyurethane by reacting diisocyanate, a high molecular weight diol, 1,1'-ferrocenedimethylethanol, and a small molecule chain extender. Then, it prepares a polyurethane with metal ion coordination function by reacting diisocyanate, a high molecular weight diol, a chain extender containing carboxyl or catechol groups, and a small molecule chain extender. The mechanoresponsive polyurethane and the metal ion coordination polyurethane are then mixed by physical blending to obtain a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments. The self-reinforcing and self-healing polyurethane film prepared by this invention can spontaneously generate iron ions under mechanical force. These iron ions can coordinate with the carboxyl or catechol groups contained in the polymer molecular chain, thereby generating a self-crosslinking reaction. Through this self-crosslinking reaction, the self-reinforcing and self-healing polyurethane film prepared by this invention can not only achieve self-healing under mechanical force but also achieve self-reinforcement of mechanical properties. The material prepared by this invention is environmentally friendly, has good mechanical properties, can achieve efficient self-healing at room temperature, and can effectively prevent crack propagation in high-pressure environments. It can be applied to fields such as protective materials in extreme marine environments. Summary of the Invention
[0004] In view of this, the present invention provides a method for preparing a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments. Specifically, the present invention provides the following technical solution:
[0005] 1. A method for preparing a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments, comprising the following steps:
[0006] 1) A polyurethane with a force-responsive function is prepared by reacting diisocyanate, high molecular weight diol, 1,1'-ferrocene diethanol, dibutyltin dilaurate and small molecule chain extender.
[0007] 2) A polyurethane with metal ion coordination function is prepared by reacting diisocyanate, high molecular weight diol, chain extender containing carboxyl or catechol groups and small molecule chain extender.
[0008] 3) The polyurethane with force response function in step 1) and the polyurethane with metal ion coordination function in step 2) are blended at a mass ratio of 1:1 to 1:2 to obtain a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments.
[0009] Further, the chain extender containing carboxyl or catechol groups mentioned in step 2) is one of 3,5-dihydroxybenzoic acid, dimethylolpropionic acid, dimethylolbutyric acid, 2,5-dihydroxybenzoic acid, and lysine-dopamine.
[0010] Furthermore, the small molecule chain extender mentioned in steps 1) and 2) is one of 1,4-butanediol, ethylene glycol, diethylene glycol, and ethylenediamine.
[0011] Further, the high molecular weight diol mentioned in steps 1) and 2) is one of polytetrahydrofuran diol, polypropylene glycol, polyethylene glycol, polytetramethylene ether diol, poly(1,4-butanediol adipate) diol, polycaprolactone diol, and polycarbonate diol, with a number average molecular weight of 1000 g / mol to 3000 g / mol.
[0012] Further, the diisocyanate mentioned in steps 1) and 2) is one of isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and diphenylmethane diisocyanate.
[0013] Furthermore, when the small molecule chain extender in step 2) is 3,5-dihydroxybenzoic acid, dimethylolpropionic acid, dimethylolbutyric acid, or 2,5-dihydroxybenzoic acid, the mass ratio in step 3) is 1:2; when the small molecule chain extender in step 2) is lysine-dopamine, the mass ratio in step 3) is 1:1.
[0014] Further, the mass fractions of each component in step 1) are: 15-35 parts of diisocyanate, 40-85 parts of high molecular weight diol, 2-20 parts of 1,1'-ferrocene diethanol, and 0.5-2.5 parts of small molecule chain extender. The mass fractions of each component in step 2) are: 15-35 parts of diisocyanate, 40-85 parts of high molecular weight diol, 0.5-25 parts of chain extender containing carboxyl or catechol groups, and 0.5-2.5 parts of small molecule chain extender.
[0015] Further, in step 2), 1.5 to 5 parts of a chain extender containing carboxyl or catechol groups are used.
[0016] Further, the preparation method of the force-responsive polyurethane in step 1) is as follows: 1,1'-ferrocene diethanol, diisocyanate and dibutyltin dilaurate are added sequentially to a high-drying polymeric diol. Under inert gas protection, the reaction is carried out at 50-60℃ for 2-4 hours to obtain a terminal isocyanate prepolymer. Then, a small molecule chain extender is added for chain extension. Under inert gas protection, the reaction is carried out at 50-60℃ for 24-48 hours to obtain a polyurethane solution. The solution is then vacuum dried at 70-90℃ to obtain the final product. The preparation method of polyurethane with metal ion coordination function in step 2) is as follows: chain extender containing carboxyl or catechol groups, diisocyanate and dibutyltin dilaurate are added sequentially to the dried polymeric diol. Under inert gas protection, the reaction is carried out at 70-90℃ for 2-4 hours to obtain isocyanate-terminated prepolymer. Then, a small molecule chain extender is added for chain extension. Under inert gas protection, the reaction is carried out at 70-90℃ for 2-4 hours to obtain polyurethane solution. The solution is then vacuum dried at 70-90℃ to obtain the final product.
[0017] Further, the blending method in step 3) is as follows: dissolve the two polyurethanes separately in an organic solvent, mix and stir to disperse for 20-30 minutes to obtain a mixed polyurethane solution, adjust the pH to 8-11 with triethylamine, and vacuum dry at 70-90°C for 24-48 hours to obtain the product. The organic solvent is one of tetrahydrofuran, N,N-dimethylformamide, acetone, butanone, and chloroform.
[0018] The beneficial effects of this invention are as follows: The self-reinforcing and self-healing polyurethane film suitable for extreme marine environments prepared by this invention introduces ferrocene, a mechanically unstable force-responsive molecule, into the polymer chain, giving it a force-responsive function. Under mechanical force, it can spontaneously generate iron ions, which coordinate with carboxyl groups or catechol contained in the polymer chain, achieving self-repair of material damage. This process is spontaneous, requiring no artificial addition, making it more intelligent. The self-healing process of the self-reinforcing and self-healing polyurethane film suitable for extreme marine environments prepared by this invention is triggered by mechanical force, enabling timely self-repair when mechanical damage occurs, preventing further crack propagation. The self-reinforcing and self-healing polyurethane film suitable for extreme marine environments prepared by this invention consists of two parts: a force-responsive polyurethane and a polyurethane with metal ion coordination function. The force-responsive polyurethane can spontaneously generate iron ions under mechanical force; the generated iron ions can further coordinate with the polyurethane with metal ion coordination function, leading to a self-crosslinking reaction. In the preparation of self-reinforcing and self-healing polyurethane films suitable for extreme marine environments, the mechanical and self-healing properties of the polyurethane film can be controlled by adjusting the amount of chain extenders containing carboxyl or catechol groups. The mechanical properties of the self-reinforcing and self-healing polyurethane film suitable for extreme marine environments prepared by this invention can be improved through a self-crosslinking reaction caused by repeated mechanical forces. Attached Figure Description
[0019] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided:
[0020] Figure 1 This diagram illustrates the self-healing mechanism of the self-reinforcing and self-healing polyurethane film suitable for extreme marine environments prepared according to the present invention.
[0021] Figure 2 These are before-and-after photos of the self-reinforcing and self-healing polyurethane films suitable for extreme marine environments prepared in Examples 1(a) and 5(b).
[0022] Figure 3 The self-reinforcing and self-healing polyurethane films prepared in Examples 1(a) and 5(b) for extreme marine environments are shown in the cyclic stress-strain curves after being pressed at 50 MPa for 5 minutes and then recovered at room temperature for 24 hours.
[0023] Figure 4 These are before and after photos of the self-reinforcing and self-healing polyurethane films prepared in Examples 1(a) and 5(b) for extreme marine environments in artificial seawater. Detailed Implementation
[0024] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0025] Figure 1 This diagram illustrates the self-healing mechanism of the self-reinforcing and self-healing polyurethane film suitable for extreme marine environments prepared according to the present invention. First, a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments is prepared by physically blending polyurethane with metal ion coordination function and polyurethane with force-responsive function. Under pressure, this polyurethane film can generate iron ions, which coordinate with carboxyl or catechol groups, leading to a self-crosslinking reaction. Through this self-crosslinking reaction, the self-reinforcing and self-healing polyurethane film suitable for extreme marine environments prepared according to the present invention can not only achieve self-healing under mechanical force but also achieve self-reinforcement of mechanical properties.
[0026] Example 1
[0027] The preparation of a self-reinforcing and self-healing polyurethane film (MC-1) suitable for extreme marine environments involves the following steps:
[0028] 1) Place 3.68 g of polytetrahydrofuran-2000 in a three-necked flask equipped with a stirrer, adjust the rotation speed to 150-250 r / min, and distill under reduced pressure for 2 h at 120 °C and a vacuum of 0.1 MPa to remove moisture; add 0.36 g of 1,1'-ferrocene dimethyl alcohol, 1.25 g of 4,4'-dicyclohexylmethane diisocyanate and 0.01 g of dibutyltin dilaurate to the dried polytetrahydrofuran-2000 in sequence, under argon protection, and react at 50-60 °C for 2-4 h to obtain a terminal isocyanate prepolymer; add 0.14 g of 1,4-butanediol for chain extension, under argon protection, and react at 50-60 °C for 24 h to obtain a polyurethane solution; dry under vacuum at 70-90 °C for 24 h to obtain a polyurethane with force-responsive properties;
[0029] 2) Place 3.68 g of polytetrahydrofuran-2000 in a three-necked flask equipped with a stirrer, adjust the rotation speed to 150–250 r / min, and distill under reduced pressure for 2 h at 120 °C and a vacuum of 0.1 MPa to remove moisture. Add 0.08 g of 3,5-dihydroxybenzoic acid (3,5-dihydroxybenzoic acid molar ratio of 5%), 1.25 g of 4,4'-dicyclohexylmethane diisocyanate, and 0.01 g of dibutyltin dilaurate sequentially to the dried polytetrahydrofuran-2000 under argon protection at 70–90 °C.
[0030] After reacting for 2–4 h, a terminal isocyanate prepolymer is obtained; 0.22 g of 1,4-butanediol is added for chain extension, and under argon protection, the reaction is carried out at 70–90 °C for 2–4 h to obtain a polyurethane solution; after vacuum drying at 70–90 °C for 24 h, a polyurethane with metal ion coordination function is obtained.
[0031] 3) Take 1g of polyurethane with force response function and 2g of polyurethane with metal ion coordination function respectively, dissolve them in an organic solvent, mix and stir for 20-30 minutes to obtain a mixed polyurethane solution; adjust the pH to 11 with triethylamine; vacuum dry at 70-90℃ for 24 hours to obtain a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments, named MC-1.
[0032] Example 2
[0033] The preparation of a self-reinforcing and self-healing polyurethane film (MC-2) suitable for extreme marine environments was carried out in the same steps as in Example 1, except that in step 2), the amount of 3,5-dihydroxybenzoic acid was 0.15 g (the molar ratio of 3,5-dihydroxybenzoic acid was 10%) and the amount of 1,4-butanediol was 0.18 g.
[0034] Example 3
[0035] The preparation of a self-reinforcing and self-healing polyurethane film (MC-3) suitable for extreme marine environments was carried out in the same steps as in Example 1, except that in step 2), the amount of 3,5-dihydroxybenzoic acid was 0.23 g (the molar ratio of 3,5-dihydroxybenzoic acid was 15%) and the amount of 1,4-butanediol was 0.13 g.
[0036] Example 4
[0037] The preparation of a self-reinforcing and self-healing polyurethane film (MC-4) suitable for extreme marine environments was carried out in the same steps as in Example 1, except that in step 2), the amount of 3,5-dihydroxybenzoic acid was 0.26 g (the molar ratio of 3,5-dihydroxybenzoic acid was 20%) and the amount of 1,4-butanediol was 0.09 g.
[0038] Example 5
[0039] The preparation of a self-reinforcing and self-healing polyurethane film (MP-1) suitable for extreme marine environments involves the following steps:
[0040] 1) Place 3.68 g of polytetrahydrofuran-2000 in a three-necked flask equipped with a stirrer, adjust the rotation speed to 150-250 r / min, and distill under reduced pressure for 2 h at 120 °C and a vacuum of 0.1 MPa to remove moisture; add 0.36 g of 1,1'-ferrocene dimethyl alcohol, 1.25 g of 4,4'-dicyclohexylmethane diisocyanate and 0.01 g of dibutyltin dilaurate to the dried polytetrahydrofuran-2000 in sequence, under argon protection, and react at 50-60 °C for 2-4 h to obtain a terminal isocyanate prepolymer; add 0.14 g of 1,4-butanediol for chain extension, under argon protection, and react at 50-60 °C for 24 h to obtain a polyurethane solution; dry under vacuum at 70-90 °C for 24 h to obtain a polyurethane with force-responsive properties;
[0041] 2) Place 3.14 g of polytetrahydrofuran-2000 in a three-necked flask equipped with a stirrer, adjust the rotation speed to 150–250 r / min, and distill under reduced pressure for 2 h at 120 °C and a vacuum of 0.1 MPa to remove moisture; then add 0.11 g of lysine-dopamine to the dried polytetrahydrofuran-2000. The molar ratio of lysine to dopamine is 5%; 0.79 g of 4,4'-dicyclohexylmethane diisocyanate and 0.01 g of dibutyltin dilaurate are reacted under argon protection at 70-90℃ for 2-4 h to obtain a terminal isocyanate prepolymer; 0.09 g of 1,4-butanediol is added for chain extension, and the reaction is carried out under argon protection at 70-90℃ for 2-4 h to obtain a polyurethane solution; after vacuum drying at 70-90℃ for 24 h, a polyurethane with metal ion coordination function is obtained, with the molar ratio of lysine to dopamine being 5%.
[0042] 3) Take 1g of polyurethane with force response function and 1g of polyurethane with metal ion coordination function respectively, dissolve them in an organic solvent, mix and stir for 20-30 minutes to obtain a mixed polyurethane solution; adjust the pH to 11 with triethylamine; vacuum dry at 70-90℃ for 24 hours to obtain a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments, named MP-1.
[0043] Example 6
[0044] The preparation of a self-reinforcing and self-healing polyurethane film (MP-2) suitable for extreme marine environments was carried out in the same steps as in Example 5, except that in step 2), the amount of lysine-dopamine was 0.22 g (the molar ratio of lysine-dopamine was 10%) and the amount of 1,4-butanediol was 0.06 g.
[0045] Example 7
[0046] The preparation of a self-reinforcing and self-healing polyurethane film (MP-3) suitable for extreme marine environments was carried out in the same steps as in Example 1, except that in step 2), the amount of lysine-dopamine was 0.31 g (the molar ratio of lysine-dopamine was 15%) and the amount of 1,4-butanediol was 0.04 g.
[0047] Example 8
[0048] The preparation of a self-reinforcing and self-healing polyurethane film (MP-4) suitable for extreme marine environments was carried out in the same steps as in Example 1, except that in step 2), the amount of lysine-dopamine was 0.42 g (the molar ratio of lysine-dopamine was 20%) and the amount of 1,4-butanediol was 0.01 g.
[0049] Test Example 1
[0050] 1. Self-healing performance test of self-reinforcing and self-healing polyurethane film suitable for extreme marine environments in air.
[0051] The self-reinforcing and self-healing polyurethane films suitable for extreme marine environments obtained in Examples 1-8 were cut into two independent segments. The two segments were then tightly bonded together along the cut edges and pressed with a force of 50 MPa for 5 minutes. The films were then left in air at room temperature for 24 hours. Tensile testing was performed on the self-reinforcing and self-healing polyurethane films before and after self-healing using a universal testing machine. The tensile strength of the self-healing polyurethane films was recorded. The self-healing efficiency was calculated based on the ratio of the tensile strength of the self-healing polyurethane film to that of the original self-healing polyurethane film. The results are shown in Table 1.
[0052] As shown in Table 1, the self-reinforcing and self-healing polyurethane film prepared by this invention, suitable for extreme marine environments, exhibits good self-healing efficiency in air at room temperature, ranging from 92% to 130%. The self-healing efficiency of MC-1 reached 130%. Subsequent test examples demonstrated that after pressing treatment, a self-crosslinking reaction occurred within the self-reinforcing and self-healing polyurethane film prepared by this invention, effectively improving the mechanical properties of the material.
[0053] 2. Self-healing efficiency test of self-reinforcing and self-healing polyurethane film suitable for extreme marine environments in artificial seawater.
[0054] The self-reinforcing and self-healing polyurethane films suitable for extreme marine environments obtained in Examples 1-8 were cut into two independent segments. The two segments were then tightly bonded together along the cut edges and pressed with a force of 50 MPa for 5 minutes. The films were then placed in artificial seawater at room temperature for 24 hours. Tensile testing was performed on the self-reinforcing and self-healing polyurethane films before and after self-healing using a universal testing machine. The tensile strength of the self-healing polyurethane films was recorded. The self-healing efficiency was calculated based on the ratio of the tensile strength of the self-healing polyurethane film to that of the original self-healing polyurethane film. The results are shown in Table 1.
[0055] As can be seen from Table 1, the self-reinforcing and self-healing polyurethane film prepared by the present invention, suitable for extreme marine environments, has good self-healing efficiency in artificial seawater, with a maximum self-healing efficiency of 142%. This indicates that the self-reinforcing and self-healing polyurethane film prepared by the present invention, suitable for extreme marine environments, can also achieve self-healing through self-crosslinking reaction in seawater.
[0056] Table 1. Test results of tensile strength and self-healing efficiency of self-reinforced and self-healing polyurethane films suitable for extreme marine environments.
[0057]
[0058] Test Example 2
[0059] The self-reinforcing and self-healing polyurethane films MC-1 and MP-1, obtained in Examples 1 and 5 and suitable for extreme marine environments, were each cut into two independent segments. The two segments of polyurethane film were then tightly bonded together along the cut edges and pressed with a force of 50 MPa for 5 minutes. After being left in air at room temperature for 24 hours, the results were as follows: Figure 2 As shown.
[0060] from Figure 2 As can be seen, after being pressed with a force of 50 MPa for 5 minutes and placed in air at room temperature for 24 hours, the self-reinforcing and self-healing polyurethane films MC-1 and MP-1 prepared by this invention, suitable for extreme marine environments, both achieved self-healing.
[0061] Test Example 3
[0062] Cyclic tensile testing was conducted on the self-reinforcing and self-healing polyurethane films MC-1 and MP-1, obtained in Examples 1 and 5 and suitable for extreme marine environments, using a universal testing machine. After each test, the polyurethane film was first pressed with a force of 50 MPa for 5 minutes, then left at room temperature for 24 hours to allow it to fully recover its deformation, and then a new round of testing was performed. The tests were repeated 4 times in total, and the results are as follows. Figure 3 As shown.
[0063] from Figure 3 As can be seen, the self-reinforcing and self-healing polyurethane film prepared by this invention, suitable for extreme marine environments, exhibits improved mechanical properties after each pressing, proving that a self-crosslinking reaction occurs inside the polyurethane film after pressing, thereby leading to improved mechanical properties.
[0064] Test Example 4
[0065] The self-reinforcing and self-healing polyurethane films MC-1 and MP-1, obtained in Examples 1 and 5 and suitable for extreme marine environments, were each cut into two independent segments. The two segments of polyurethane film were then tightly bonded together along the cut edges and pressed with a force of 50 MPa for 5 minutes. The mixtures were then placed in artificial seawater at room temperature for 24 hours. The results are as follows: Figure 4 As shown.
[0066] from Figure 4 As can be seen, after being pressed with a force of 50 MPa for 5 minutes and placed in artificial seawater at room temperature for 24 hours, the polyurethane film prepared by this invention can complete self-repair in artificial seawater.
[0067] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.
Claims
1. A method for preparing a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments, characterized in that, The preparation steps are as follows: 1) A polyurethane with force-responsive function is prepared by reacting diisocyanate, high molecular weight diol, 1,1'-ferrocene diethanol, dibutyltin dilaurate and small molecule chain extender. 2) A polyurethane with metal ion coordination function is prepared by reacting diisocyanate, high molecular weight diol, chain extender containing carboxyl or catechol groups and small molecule chain extender. 3) The polyurethane with force response function in step 1) and the polyurethane with metal ion coordination function in step 2) are blended at a mass ratio of 1:1 to 1:2 to obtain a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments. The self-reinforcing and self-healing polyurethane film can complete self-healing by pressing it with a force of 50 MPa for 5 minutes at room temperature and then leaving it at room temperature for 24 hours.
2. The method for preparing a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments according to claim 1, characterized in that, The chain extender containing carboxyl or catechol groups mentioned in step 2) is one of 3,5-dihydroxybenzoic acid, dimethylolpropionic acid, dimethylolbutyric acid, 2,5-dihydroxybenzoic acid, and lysine-dopamine.
3. The method for preparing a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments according to claim 1, characterized in that, The small molecule chain extender mentioned in steps 1) and 2) is one of 1,4-butanediol, ethylene glycol, diethylene glycol, and ethylenediamine.
4. The method for preparing a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments according to claim 1, characterized in that, The high molecular weight diol mentioned in steps 1) and 2) is one of polytetrahydrofuran diol, polypropylene glycol, polyethylene glycol, poly(1,4-butanediol adipate), polycaprolactone diol, and polycarbonate diol, with a number average molecular weight of 1000 g / mol to 3000 g / mol.
5. The method for preparing a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments according to claim 1, characterized in that, The diisocyanate mentioned in steps 1) and 2) is one of isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and diphenylmethane diisocyanate.
6. The method for preparing a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments according to claim 1, characterized in that, When the small molecule chain extender in step 2) is 3,5-dihydroxybenzoic acid, dimethylolpropionic acid, dimethylolbutyric acid, or 2,5-dihydroxybenzoic acid, the mass ratio in step 3) is 1:
2. When the small molecule chain extender in step 2) is lysine-dopamine, the mass ratio in step 3) is 1:
1.
7. The method for preparing a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments according to claim 1. Its features are, The mass fractions of each component in step 1) are: 15-35 parts of diisocyanate, 40-85 parts of high molecular weight diol, 2-20 parts of 1,1'-ferrocene diethanol, and 0.5-2.5 parts of small molecule chain extender. The mass fractions of each component in step 2) are: 15-35 parts of diisocyanate, 40-85 parts of high molecular weight diol, 0.5-25 parts of chain extender containing carboxyl or catechol groups, and 0.5-2.5 parts of small molecule chain extender.
8. The method for preparing a self-reinforcing and self-healing polyurethane film suitable for extreme marine environments according to claim 1. Its features are, The blending method in step 3) is as follows: dissolve the two polyurethanes separately in an organic solvent, mix and stir to disperse for 20-30 min to obtain a mixed polyurethane solution, adjust the pH to 8-11 with triethylamine, and vacuum dry at 70-90℃ for 24-48 h to obtain the product. The organic solvent is one of tetrahydrofuran, N,N-dimethylformamide, acetone, butanone, and chloroform.