Self-repairable and recyclable super-strong and super-tough thermosetting polyurethane elastomer as well as preparation method and application thereof
By introducing hydrogen-bonded donor-acceptor mismatched amide urea groups and dynamic covalent bonds into thermosetting polyurethane materials, a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer was prepared, solving the problems of tensile properties and recyclability of thermosetting materials and achieving a combination of high mechanical properties and self-healing properties.
Patent Information
- Application Number
- CN202511163440.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-19
- Publication Date
- 2025-12-23
AI Technical Summary
The limited tensile properties, non-recyclability, and lack of self-healing properties of existing thermosetting polyurethane materials due to covalent cross-linking restrict their further application and development.
By introducing amide urea groups with a mismatch in the number of hydrogen bond donors and acceptors, and combining dynamic covalent and non-covalent bonds, a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer is prepared. A polyurethane material with borate bonds is generated by reacting polycaprolactone, 4,4'-dicyclohexylmethane diisocyanate, catalyst, chain extender and end capping agent in a specific ratio.
It significantly improves the tensile strength, elongation at break, and toughness of the material, while also possessing excellent recyclability and self-healing properties, thus realizing a thermosetting polyurethane material that combines high mechanical properties with dynamic performance.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of high-performance polyurethane elastomer technology, and specifically relates to a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer, its preparation method and application. Background Technology
[0002] Polyurethane (PU) possesses excellent mechanical properties due to its phase separation characteristics and is widely used in furniture, electrical appliances, construction, and other fields. PU is mainly prepared from fossil-derived polyols and isocyanates, and its molecular structure contains repeating urethane groups (-NHCOO-). The first discovery of PU can be traced back to the early 1930s, when it was synthesized by a team led by German scientist Bayer.
[0003] During the reaction process, various functions of polyurethane are achieved by changing the types of reactants such as chain extenders, crosslinking agents, and foaming agents. However, the limited tensile properties, non-recyclability, and lack of self-healing properties of thermosetting polyurethane materials due to covalent crosslinking restrict their further application and development. The recycling and reuse of thermosetting materials has become a major challenge. Currently, it is widely believed that effectively combining dynamic covalent and non-covalent bonds into the polymer network helps dissipate energy and resist external stress, thereby improving the recyclability and tensile toughness of thermosetting materials.
[0004] As is well known, hydrogen bonds, as one of the most common non-covalent bonds, can effectively transmit stress and thus strengthen polymers. In particular, when the mechanical response of a polymer material is primarily driven by the dynamic breaking and recombination of hydrogen bonds, the material can simultaneously exhibit toughening and strengthening effects. From the perspective of performance regulation and practical applications of thermosetting polymers, this characteristic shows great appeal. However, when thermosetting materials are subjected to external forces, the excessively strong supramolecular aggregates (such as multiple hydrogen bonds) and the constraints of covalent cross-linked networks can significantly reduce the efficiency of dissociation or energy dissipation, thereby weakening mechanical properties, self-healing properties, and recyclability. Therefore, there is an urgent need to propose a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer and its preparation method to solve the above-mentioned technical problems. Summary of the Invention
[0005] In order to overcome the shortcomings and deficiencies of the existing technology and improve the contradiction between the mechanical properties and self-healing and recyclable properties of thermosetting polyurethane, the primary objective of this invention is to provide a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer.
[0006] Another object of the present invention is to provide a method for preparing the above-mentioned self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer.
[0007] Another object of the present invention is to provide the application of the above-mentioned self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer.
[0008] The objective of this invention is achieved through the following technical solution:
[0009] A self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer is disclosed. This polyurethane elastomer is produced by reacting polycaprolactone as the soft segment, 4,4'-dicyclohexylmethane diisocyanate as the hard segment, dibutyltin dilaurate as the catalyst, oxaloyl dihydrazide and carbazide as chain extenders, and 3-aminophenylboronic acid as the end-capping agent to generate a polyurethane linear chain. The elastomer is then dehydrated under vacuum to obtain a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer with borate bonds.
[0010] The polyurethane elastomer has a tensile strength of up to 69.15 MPa, an elongation at break of up to 1559%, and a toughness of up to 461.8 MJ / m. -3 .
[0011] The polycaprolactone is a polycaprolactone with a number average molecular weight of 3000 g / mol.
[0012] The molar ratio of polycaprolactone, 4,4'-dicyclohexylmethane diisocyanate, chain extender and 3-aminophenylboronic acid is 10:20:5-10:0-10, preferably 10:20:7.5:5.
[0013] The preparation method of the above-mentioned self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer includes the following steps: heating polycaprolactone and evacuating it to remove internal moisture, then adding a solvent and 4,4'-dicyclohexylmethane diisocyanate after purging with nitrogen, and then adding a catalyst to carry out a prepolymerization reaction. After the prepolymerization reaction is completed, adding oxaloyl dihydrazide and carbamate hydrazide to carry out a chain extension reaction, and finally adding 3-aminophenylboronic acid to carry out a capping reaction to obtain a phenylboronic acid-capped polyurethane elastomer. Then, the elastomer is dehydrated by vacuum drying to obtain a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer.
[0014] The process of heating and vacuuming to remove internal moisture involves heating the temperature to 120°C and then vacuuming to remove the moisture.
[0015] The nitrogen gas is introduced after the temperature has been cooled to 70°C.
[0016] The prepolymerization reaction was carried out at a temperature of 70°C for 4 hours; the chain extension reaction was carried out at a temperature of 50°C for 6 hours; and the end-capping reaction was carried out at a temperature of 70°C for 3 hours.
[0017] The solvent is N,N-dimethylformamide.
[0018] The amount of catalyst used is one-thousandth of the total mass of polycaprolactone, 4,4'-dicyclohexylmethane diisocyanate, chain extender and 3-aminophenylboronic acid.
[0019] The above-mentioned self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer is used in flexible electronics and wearable devices. The polyurethane elastomer is combined with conductive materials to be used in flexible electronics and wearable devices.
[0020] The present invention has the following advantages and beneficial effects compared with the prior art:
[0021] This invention introduces amide urea groups with a mismatch in the number of hydrogen bond donors and acceptors into a covalently cross-linked network, optimizing their binding energy to avoid excessively strong or weak hydrogen bond aggregates, thereby improving the ability to dissipate energy and resist external stress. This strategy significantly enhances and toughens thermosetting polyurethanes, exhibiting ultra-high tensile strength and elongation at break (69.15 MPa and 1559%, respectively), reaching as high as 461.8 MJ / m². -3 The toughness value is high. Furthermore, this high-performance thermosetting polyurethane also possesses excellent recyclability, self-healing properties, and notch resistance, providing a feasible approach from a molecular design perspective for synthesizing thermosetting elastomers with both high mechanical properties and high dynamics. Attached Figure Description
[0022] Figure 1 This is a technical circuit diagram of the thermosetting polyurethane elastomers prepared in Examples 7-10 of the present invention.
[0023] Figure 2 These are infrared spectra of the thermosetting polyurethane elastomers prepared in Examples 7-10 of this invention.
[0024] Figure 3 These are mechanical property diagrams of the thermosetting polyurethane elastomers prepared in Examples 7-10 of this invention.
[0025] Figure 4 This is a diagram showing the effect of the thermosetting polyurethane elastomer prepared in Example 10 of the present invention under load.
[0026] Figure 5 This describes the self-healing mechanical properties of the thermosetting polyurethane elastomer prepared in Example 10 of this invention.
[0027] Figure 6 The mechanical properties of the thermosetting polyurethane elastomer prepared in Example 10 of this invention after multiple solution reprocessing. Detailed Implementation
[0028] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.
[0029] Example 1
[0030] S1: Polycaprolactone with a molecular weight of 3000 g / mol was heated to 120°C and then vacuumed to remove internal moisture. 15 g of the dehydrated polycaprolactone was cooled to 70°C and nitrogen gas was introduced. 3 g of 4,4'-dicyclohexylmethane diisocyanate, 50 ml of N,N-dimethylformamide, and 0.02 g of dibutyltin dilaurate catalyst were added. The temperature was maintained at 70°C and stirred for 4 h to produce an isocyanate-terminated polyurethane prepolymer. Subsequently, 0.4564 g of oxaloyl dihydrazine was added, and the temperature was lowered to 50°C and stirred for 6 h to extend the chain. Finally, 0.343 g of 3-aminophenylboronic acid was added, and the temperature was maintained at 70°C and stirred for 6 h to end-capping the chain, yielding a phenylboronic acid-terminated polyurethane elastomer.
[0031] S2: The phenylboronic acid-terminated polyurethane elastomer was vacuum dried and cured at 80°C for 24 hours to obtain the final thermosetting polyurethane elastomer.
[0032] Example 2
[0033] S1: Polycaprolactone with a molecular weight of 3000 g / mol was heated to 120°C and then vacuumed to remove internal moisture. 15 g of the dehydrated polycaprolactone was cooled to 70°C and nitrogen gas was introduced. 3 g of 4,4'-dicyclohexylmethane diisocyanate, 50 ml of N,N-dimethylformamide, and 0.02 g of dibutyltin dilaurate catalyst were added. The temperature was maintained at 60°C and stirred for 5 h to produce an isocyanate-terminated polyurethane prepolymer. Subsequently, 0.3484 g of carbazide was added, and the temperature was lowered to 50°C and stirred for 6 h to extend the chain. Finally, 0.343 g of 3-aminophenylboronic acid was added, and the temperature was maintained at 50°C and stirred for 8 h to end-capping the chain, yielding a phenylboronic acid-terminated polyurethane elastomer.
[0034] S2: The phenylboronic acid-terminated polyurethane elastomer was vacuum dried and cured at 90°C for 24 hours to obtain the final thermosetting polyurethane elastomer.
[0035] Example 3
[0036] S1: Polycaprolactone with a molecular weight of 3000 g / mol was heated to 120°C and then vacuum-sealed to remove internal moisture. 15 g of the dehydrated polycaprolactone was cooled to 70°C and nitrogen gas was introduced. 3 g of 4,4'-dicyclohexylmethane diisocyanate, 50 ml of N,N-dimethylformamide, and 0.02 g of dibutyltin dilaurate catalyst were added. The temperature was maintained at 80°C and the prepolymerization reaction was stirred for 3 h to generate an isocyanate-terminated polyurethane prepolymer. Subsequently, 0.6086 g of oxaloyl dihydrazine was added, and the temperature was lowered to 70°C and the chain extension reaction was stirred for 4 h to obtain a linear polyurethane elastomer.
[0037] S2: The linear polyurethane elastomer is vacuum dried and cured at 80°C for 24 hours to obtain the final thermoplastic polyurethane elastomer.
[0038] Example 4
[0039] S1: Polycaprolactone with a molecular weight of 3000 g / mol was heated to 120°C and then vacuum-sealed to remove internal moisture. 15 g of the dehydrated polycaprolactone was cooled to 70°C and nitrogen gas was introduced. 3 g of 4,4'-dicyclohexylmethane diisocyanate, 50 ml of N,N-dimethylformamide, and 0.02 g of dibutyltin dilaurate catalyst were added. The temperature was maintained at 80°C and the mixture was stirred for 3 h to produce an isocyanate-terminated polyurethane prepolymer. Subsequently, 0.4644 g of carbazide was added, and the mixture was cooled to 70°C and stirred for 4 h to extend the chain, yielding a linear polyurethane elastomer.
[0040] S2: The linear polyurethane elastomer is vacuum dried and cured at 80°C for 24 hours to obtain the final thermoplastic polyurethane elastomer.
[0041] Example 5
[0042] S1: Polycaprolactone with a molecular weight of 3000 g / mol was heated to 120°C and then vacuumed to remove internal moisture. 7.5 g of the dehydrated polycaprolactone was cooled to 70°C and nitrogen gas was introduced. 3 g of 4,4'-dicyclohexylmethane diisocyanate, 50 ml of N,N-dimethylformamide, and 0.01 g of dibutyltin dilaurate catalyst were added. The temperature was maintained at 70°C and the mixture was stirred for 3 h to produce an isocyanate-terminated polyurethane prepolymer. Subsequently, 0.6968 g of carbazide was added, and the temperature was lowered to 50°C and the mixture was stirred for 8 h to extend the chain. Finally, 0.686 g of 3-aminophenylboronic acid was added, and the temperature was raised to 70°C and the mixture was stirred for 8 h to obtain a phenylboronic acid-terminated polyurethane elastomer.
[0043] S2: The phenylboronic acid-terminated polyurethane elastomer was vacuum dried and cured at 100°C for 24 hours to obtain the final thermosetting polyurethane elastomer.
[0044] Example 6
[0045] S1: Polycaprolactone with a molecular weight of 3000 g / mol was heated to 120°C and then vacuumed to remove internal moisture. 7.5 g of the dehydrated polycaprolactone was cooled to 70°C and nitrogen gas was introduced. 3 g of 4,4'-dicyclohexylmethane diisocyanate, 50 ml of N,N-dimethylformamide, and 0.01 g of dibutyltin dilaurate catalyst were added. The temperature was maintained at 70°C and the mixture was stirred for 3 h to produce an isocyanate-terminated polyurethane prepolymer. Subsequently, 0.9128 g of oxaloyl dihydrazine was added, and the temperature was lowered to 50°C and the mixture was stirred for 8 h to extend the chain. Finally, 0.686 g of 3-aminophenylboronic acid was added, and the temperature was raised to 70°C and the mixture was stirred for 8 h to obtain a phenylboronic acid-terminated polyurethane elastomer.
[0046] S2: The phenylboronic acid-terminated polyurethane elastomer was vacuum dried and cured at 100°C for 24 hours to obtain the final thermosetting polyurethane elastomer.
[0047] Example 7
[0048] S1: Polycaprolactone with a molecular weight of 3000 g / mol is heated to 120°C and then vacuum-sealed to remove internal moisture. Figure 1 As shown, 15g of dehydrated polycaprolactone was cooled to 70℃ and then nitrogen gas was introduced. 4.5g of 4,4'-dicyclohexylmethane diisocyanate, 50ml of N,N-dimethylformamide, and 0.02g of dibutyltin dilaurate catalyst were added. The temperature was maintained at 70℃ and the mixture was stirred for 3h to produce an isocyanate-terminated polyurethane prepolymer. Subsequently, 0.5804g of carbazide was added and the temperature was maintained at 70℃ for 4h to extend the chain. Finally, 0.343g of 3-aminophenylboronic acid was added and the temperature was maintained at 70℃ for 4h to obtain a phenylboronic acid-terminated polyurethane elastomer.
[0049] S2: The phenylboronic acid-terminated polyurethane elastomer was vacuum-cured at 80°C for 24 hours to obtain the final thermosetting polyurethane elastomer. The infrared spectrum is as follows: Figure 2 As shown, the mechanical properties are as follows Figure 3 As shown.
[0050] Example 8
[0051] S1: Polycaprolactone with a molecular weight of 3000 g / mol is heated to 120°C and then vacuum-sealed to remove internal moisture. Figure 1 As shown, 15g of dehydrated polycaprolactone was cooled to 70℃ and then nitrogen gas was introduced. 4.5g of 4,4'-dicyclohexylmethane diisocyanate, 50ml of N,N-dimethylformamide, and 0.02g of dibutyltin dilaurate catalyst were added. The temperature was maintained at 70℃ and the mixture was stirred for 3h to produce an isocyanate-terminated polyurethane prepolymer. Subsequently, 0.7608g of oxaloyl dihydrazine was added and the mixture was stirred at 70℃ for 4h to extend the chain. Finally, 0.343g of 3-aminophenylboronic acid was added and the mixture was stirred at 70℃ for 4h to obtain a phenylboronic acid-terminated polyurethane elastomer.
[0052] S2: The phenylboronic acid-terminated polyurethane elastomer was vacuum-cured at 80°C for 24 hours to obtain the final thermosetting polyurethane elastomer. The infrared spectrum is as follows: Figure 2 As shown, the mechanical properties are as follows Figure 3 As shown.
[0053] Example 9
[0054] S1: Polycaprolactone with a molecular weight of 3000 g / mol is heated to 120°C and then vacuum-sealed to remove internal moisture. Figure 1As shown, 15g of dehydrated polycaprolactone was cooled to 70℃ and then nitrogen gas was introduced. 4.5g of 4,4'-dicyclohexylmethane diisocyanate, 50ml of N,N-dimethylformamide, and 0.02g of dibutyltin dilaurate catalyst were added. The mixture was stirred at 70℃ for 3 hours to produce an isocyanate-terminated polyurethane prepolymer. Subsequently, 0.3804g of oxaloyl dihydrazide and 0.2902g of carbazide were added together, and the mixture was stirred at 70℃ for 4 hours to extend the chain. Finally, 0.343g of 3-aminophenylboronic acid was added, and the mixture was stirred at 70℃ for 4 hours to obtain a phenylboronic acid-terminated polyurethane elastomer.
[0055] S2: The phenylboronic acid-terminated polyurethane elastomer was vacuum-cured at 80°C for 24 hours to obtain the final thermosetting polyurethane elastomer. The infrared spectrum is as follows: Figure 2 As shown, the mechanical properties are as follows Figure 3 As shown.
[0056] Example 10
[0057] S1: Polyurethanes prepared according to Examples 1 and 2 respectively using oxaloyl dihydrazide and carbohydrazide as chain extenders; the two polyurethanes are mixed at a mass ratio of 1:1 to obtain a mixed polyurethane solution.
[0058] S2: This mixed polyurethane solution was cured at 90℃ for 24 hours to obtain a thermosetting polyurethane elastomer crosslinked with borate ester bonds. The infrared spectrum is as follows. Figure 2 As shown, the mechanical properties are as follows Figure 3 As shown, the load-bearing effect is as follows Figure 4 As shown.
[0059] Example 11
[0060] S1: Polyurethanes prepared according to Examples 1 and 2 respectively using oxaloyl dihydrazide and carbohydrazide as chain extenders; the two polyurethanes were mixed at a mass ratio of 2:1 to obtain a mixed polyurethane solution.
[0061] S2: The mixed polyurethane solution is cured at 100°C for 12 hours to obtain a thermosetting polyurethane elastomer with borate ester crosslinking.
[0062] Example 12
[0063] S1: Polyurethanes prepared according to Examples 1 and 2 respectively using oxaloyl dihydrazide and carbohydrazide as chain extenders; the two polyurethanes are mixed at a mass ratio of 1:2 to obtain a mixed polyurethane solution.
[0064] S2: The mixed polyurethane solution is cured at 100°C for 12 hours to obtain a thermosetting polyurethane elastomer with borate ester crosslinking.
[0065] Comparative Example 1
[0066] S1: Polycaprolactone with a molecular weight of 3000 g / mol was heated to 120°C and then vacuumed to remove internal moisture. 15 g of the dehydrated polycaprolactone was cooled to 70°C and nitrogen gas was introduced. 3 g of 4,4'-dicyclohexylmethane diisocyanate, 50 ml of N,N-dimethylformamide, and 0.02 g of dibutyltin dilaurate catalyst were added. The temperature was maintained at 70°C and stirred for 3 h to produce an isocyanate-terminated polyurethane prepolymer. Then, 0.645 g of isoflurane diamine was added and stirred for 4 h to extend the chain. Finally, 0.343 g of 3-aminophenylboronic acid was added and stirred for 4 h to obtain a phenylboronic acid-terminated polyurethane elastomer.
[0067] S2: The phenylboronic acid-terminated polyurethane elastomer was vacuum dried and cured at 80°C for 24 hours to obtain the final thermosetting polyurethane elastomer.
[0068] Comparative Example 2
[0069] S1: Polycaprolactone with a molecular weight of 3000 g / mol was heated to 120°C and then vacuumed to remove internal moisture. 15 g of the dehydrated polycaprolactone was cooled to 70°C and nitrogen gas was introduced. 3 g of 4,4'-dicyclohexylmethane diisocyanate, 50 ml of N,N-dimethylformamide and 0.02 g of dibutyltin dilaurate catalyst were added. The temperature was maintained at 70°C and stirred for 3 h to produce an isocyanate-terminated polyurethane prepolymer. Then 0.86 g of isophorone diamine was added together and stirred for 4 h to obtain an isophorone diamine chain-extended polyurethane solution.
[0070] S2: The isoflurane diamine chain-extended polyurethane solution was vacuum dried and cured at 80°C for 24 hours to obtain the final thermoplastic polyurethane elastomer.
[0071] Comparative Example 3
[0072] S1: Polycaprolactone with a molecular weight of 3000 g / mol was heated to 120°C and then vacuumed to remove internal moisture. 15 g of the dehydrated polycaprolactone was cooled to 70°C and nitrogen gas was introduced. 3 g of 4,4'-dicyclohexylmethane diisocyanate, 50 ml of N,N-dimethylformamide, and 0.02 g of dibutyltin dilaurate catalyst were added. The temperature was maintained at 70°C and stirred for 3 h to produce an isocyanate-terminated polyurethane prepolymer. Then, 0.4031 g of isoflurane diamine was added and stirred for 4 h to extend the chain. Finally, 0.5145 g of 3-aminophenylboronic acid was added and stirred for 5 h to obtain a phenylboronic acid-terminated polyurethane elastomer.
[0073] S2: The phenylboronic acid-terminated polyurethane elastomer was vacuum dried and cured at 90°C for 24 hours to obtain the final thermosetting polyurethane elastomer.
[0074] The thermosetting polyurethane elastomers obtained in the above examples and comparative examples were dissolved in N,N-dimethylformamide, and then cast into a polytetrafluoroethylene mold for curing to obtain a coating with a thickness of 0.5 mm-0.6 mm. Evaluation tests were then conducted.
[0075] (1) Examples 7-10 were characterized by Fourier transform infrared spectroscopy, and the results are as follows: Figure 2 As shown: 2270cm -1 The characteristic peak at that point corresponds to the time it takes for the isocyanate to react completely.
[0076] (2) Mechanical property testing:
[0077] The sample was subjected to a vertical tensile test at room temperature using a SUST model electronic universal testing machine manufactured in Zhuhai, China, at a tensile speed of 50 mm / min. The sample was made into a dumbbell shape with dimensions of 75 × 4 × 0.5 mm.
[0078] Table 1 shows the tensile strength and toughness of Examples 1-12 and Comparative Examples 1-3 (data were measured in parallel three times, and the final values are presented as averages). The results in Table 1 show that the hydrogen bonds formed by the acylhydrazide exhibit higher strength and toughness than ordinary aliphatic diamines. Furthermore, the acylhydrazide with a mismatch in the number of hydrogen bond donors and acceptors (oxaloyl dihydrazide and carbazone) exhibits higher strength and toughness than a single acylhydrazide.
[0079] (3) Repair efficiency of heat-induced self-repair:
[0080] Cut a dumbbell-shaped thermosetting polyurethane elastomer strip into two pieces with a knife, then put the broken surfaces together and keep them at a high temperature for a certain period of time to complete the self-healing process.
[0081] The mechanical properties of the repaired specimen were tested using a SUST model electronic universal testing machine manufactured in Zhuhai, China, at room temperature and a tensile speed of 50 mm / min. The specimens were prepared in a dumbbell shape, measuring 75 × 4 × 0.5 mm, and the tensile test results are as follows. Figure 5 As shown.
[0082] (4) The reprocessability of thermosetting polyurethane elastomers:
[0083] The thermosetting elastomer was cut into fragments, then dissolved in N,N-dimethylformamide at 90°C. The resulting fragments were poured into a mold and vacuum-dried to cure. This process was repeated six times, and the mechanical properties after each reprocessing were tested. The results are as follows: Figure 6 As shown.
[0084] Table 1. Performance test results of thermosetting polyurethane elastomers obtained in Examples 1-12 and Comparative Examples 1-3
[0085]
[0086]
[0087] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer, characterized in that: This polyurethane elastomer is a self-healing and recyclable thermosetting polyurethane elastomer with borate ester bonds, produced by reacting polycaprolactone as the soft segment, 4,4'-dicyclohexylmethane diisocyanate as the hard segment, dibutyltin dilaurate as the catalyst, oxaloyl dihydrazide and carbazide as chain extenders, and 3-aminophenylboronic acid as the end-capping agent to generate a linear polyurethane chain. The elastomer is then dehydrated under vacuum to obtain a self-healing and recyclable thermosetting polyurethane elastomer with borate ester bonds.
2. The self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer according to claim 1, characterized in that: The polyurethane elastomer has a tensile strength of up to 69.15 MPa, an elongation at break of up to 1559%, and a toughness of up to 461.8 MJ / m. -3 .
3. The self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer according to claim 1, characterized in that: The polycaprolactone is a polycaprolactone with a number average molecular weight of 3000 g / mol.
4. The self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer according to claim 1, characterized in that: The molar ratio of polycaprolactone, 4,4'-dicyclohexylmethane diisocyanate, chain extender and 3-aminophenylboronic acid is 10:20:5-10:0-10.
5. The self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer according to claim 4, characterized in that: The molar ratio of polycaprolactone, 4,4'-dicyclohexylmethane diisocyanate, chain extender and 3-aminophenylboronic acid is 10:20:7.5:
5.
6. A method for preparing a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer according to any one of claims 1-5, characterized in that... The process includes the following steps: heating polycaprolactone and evacuating it to remove internal moisture, then adding a solvent and 4,4'-dicyclohexylmethane diisocyanate after purging with nitrogen, followed by the addition of a catalyst for prepolymerization. After the prepolymerization reaction is complete, adding oxaloyl dihydrazide and carbazide for chain extension, and finally adding 3-aminophenylboronic acid for end-capping to obtain a phenylboronic acid-terminated polyurethane elastomer. This elastomer is then dehydrated under vacuum to obtain a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer.
7. The method for preparing a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer according to claim 6, characterized in that: The process of heating and vacuuming to remove internal moisture involves heating to 120°C and then vacuuming to remove moisture; the process of introducing nitrogen gas involves cooling to 70°C and then introducing nitrogen gas; and the solvent is N,N-dimethylformamide.
8. The method for preparing a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer according to claim 6, characterized in that: The prepolymerization reaction was carried out at a temperature of 70°C for 4 hours; the chain extension reaction was carried out at a temperature of 50°C for 6 hours; and the end-capping reaction was carried out at a temperature of 70°C for 3 hours.
9. The method for preparing a self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer according to claim 5, characterized in that: The amount of catalyst used is one-thousandth of the total mass of polycaprolactone, 4,4'-dicyclohexylmethane diisocyanate, chain extender and 3-aminophenylboronic acid.
10. The application of the self-healing and recyclable ultra-strong and ultra-tough thermosetting polyurethane elastomer according to claim 1 in flexible electronics and wearable devices.