High-toughness self-repairing modified polyurethane material and preparation method thereof

Abstract

This invention relates to the field of polyurethane materials, specifically to a high-strength, high-toughness, self-healing modified polyurethane material and its preparation method. This invention addresses the problem that existing polyurethane materials are prone to damage, leading to performance degradation and even failure, and lack self-healing capabilities, thus limiting their application in applications requiring high toughness and durability. The preparation method uses polytetramethylene ether glycol and isophorone diisocyanate as main raw materials to prepare the polyurethane material. Adding D-A bond Schiff base tetraol to participate in the reaction enhances the crosslinking degree of the polyurethane material and imparts self-healing properties. Furthermore, 4,4'-dithiodiphenylamine further enhances the self-healing effect. Finally, adding isocyanate-based graphene improves the mechanical properties of the polyurethane material, resulting in a polyurethane material with high strength, toughness, and self-healing properties, thus enhancing the reliability and service life of the polyurethane material in practical applications.

Description

Technical Field

[0001] This invention relates to the field of polyurethane materials, specifically to a high-strength, tough, self-healing modified polyurethane material and its preparation method. Background Technology

[0002] Polyurethane is a polymer synthesized from isocyanates and polyols, possessing characteristics such as chemical resistance, durability, and good flexibility. This material is widely used in various fields, from household goods and automotive interiors to construction and electronics. However, while traditional polyurethane materials exhibit excellent performance, they are prone to damage such as microcracks and scratches during long-term use, leading to performance degradation and even failure. Furthermore, they lack self-healing capabilities, limiting their application in applications requiring high toughness and durability.

[0003] Therefore, developing a high-strength, tough, self-healing modified polyurethane material and its preparation method is of great practical significance. Summary of the Invention

[0004] In order to overcome the above-mentioned technical problems, the present invention aims to provide a high-strength and tough self-healing modified polyurethane material and its preparation method, which solves the problems that existing polyurethane materials are prone to damage, leading to performance degradation or even failure, and lack self-healing ability, thus limiting their application in applications requiring high toughness and durability.

[0005] The objective of this invention can be achieved through the following technical solutions: In a first aspect, this application provides a high-strength, high-toughness, self-healing modified polyurethane material, comprising the following components in parts by weight: 20-25 parts of polytetramethylene ether glycol, 3-9 parts of DA-bonded Schiff base tetraol, 10-12 parts of isophorone diisocyanate, 0.04-0.06 parts of dibutyltin dilaurate, 0.5-1.3 parts of 4,4'-dithiodiphenylamine, 0.3-1.5 parts of isocyanate-based graphene, and 50-55 parts of tetrahydrofuran; The DA-bonded Schiff base tetraol is prepared by the following steps: Step a1: Add terephthalaldehyde and concentrated sulfuric acid to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection and stir for 10-20 min at 20-25℃ and 200-300 r / min. Then add N-bromosuccinimide and continue stirring at 70-75℃ for 4-6 h. After the reaction is complete, cool the product to room temperature and pour it into ice water. Then filter under vacuum. Add the filter cake to dichloromethane and wash 2-3 times with sodium bicarbonate solution and saturated sodium chloride solution. Dry with anhydrous sodium sulfate and then filter under vacuum. Remove the solvent by rotary evaporation of the filtrate to obtain dibromo-terephthalaldehyde. Step a2: Dibromo-terephthalaldehyde, furfuryl alcohol, triethylamine, and N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 20-25°C and 200-300 r / min for 10-20 min. Then, the temperature was raised to 50-60°C and the mixture was stirred for 3-5 h. After that, the temperature was raised to 90-100°C and the mixture was stirred for 8-10 h. After the reaction was completed, the reaction product was cooled to room temperature and then filtered under vacuum. The solvent was removed by rotary evaporation of the filtrate to obtain difuryl-terephthalaldehyde. Step a3: Difurfuryl terephthalaldehyde, N-phenylmaleimide, and tetrahydrofuran were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 0-5℃ and 200-300 r / min for 30-60 min. Then, the temperature was raised to 60-70℃ and the mixture was stirred for 10-15 h. After the reaction was completed, the reaction product was cooled to room temperature and then poured into petroleum ether. The mixture was then vacuum filtered. The filter cake was washed 2-3 times with methanol and then placed in a vacuum drying oven and dried at 60-70℃ for 2-3 h to obtain DA-bonded terephthalaldehyde. Step a4: Add DA-bonded terephthalaldehyde, 2-amino-1,3-propanediol, potassium carbonate, and N,N-dimethylformamide to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection and stir the reaction at 20-25℃ and 200-300 r / min for 10-20 min. Then raise the temperature to 80-90℃ and continue stirring for 10-15 h. After the reaction is complete, cool the reaction product to room temperature, then filter under vacuum. Remove the solvent by rotary evaporation of the filtrate to obtain DA-bonded Schiff base tetraol.

[0006] In a preferred embodiment of the present invention, the ratio of terephthalaldehyde, concentrated sulfuric acid and N-bromosuccinimide in step a1 is 10 mmol: 20-25 mL: 23-25 ​​mmol.

[0007] In a preferred embodiment of the present invention, the concentrated sulfuric acid in step a1 has a mass fraction of 98%; and the sodium bicarbonate solution has a mass fraction of 5-6%.

[0008] In a preferred embodiment of the present invention, the ratio of dibromo-terephthalaldehyde, furfuryl alcohol, triethylamine and N,N-dimethylformamide in step a2 is 10 mmol: 20 mmol: 25-35 mmol: 70-80 mL.

[0009] In a preferred embodiment of the present invention, the ratio of difurfuryl terephthalaldehyde, N-phenylmaleimide and tetrahydrofuran in step a3 is 10 mmol: 20 mmol: 70-80 mL.

[0010] In a preferred embodiment of the present invention, the ratio of the amounts of DA-bonded terephthalaldehyde, 2-amino-1,3-propanediol, potassium carbonate, and N,N-dimethylformamide in step a4 is 10 mmol: 20 mmol: 25-35 mmol: 100-120 mL.

[0011] In a preferred embodiment of the present invention, the isocyanate-based graphene is prepared by the following steps: Step b1: Add graphite powder, sodium nitrate, and concentrated sulfuric acid to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 0-5℃ and 200-300 r / min for 2-3 hours. Then, raise the temperature to 15-20℃ and continue stirring for 1-2 hours. Add potassium permanganate and raise the temperature to 35-40℃ and continue stirring for 1-2 hours. Add deionized water and continue stirring for 2-3 hours. Add hydrogen peroxide solution and continue stirring for 30-40 minutes. After the reaction is complete, cool the reaction product to room temperature, centrifuge, and wash the precipitate 2-3 times with hydrochloric acid solution and distilled water. Then, place it in a vacuum drying oven and dry it at 70-80℃ for 2-3 hours to obtain graphene oxide. Step b2: Add propyltriethoxysilane isocyanate, anhydrous ethanol, and deionized water to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 20-25℃ and a stirring rate of 200-300 r / min for 10-20 min. Then adjust the pH to 4-5 with hydrochloric acid solution and continue stirring for 30-50 min. Then add graphene oxide and heat to 60-80℃ and continue stirring for 5-7 h. After the reaction is complete, cool the reaction product to room temperature, centrifuge, wash the precipitate 2-3 times with distilled water, and then place it in a vacuum drying oven at 50-60℃ for 2-3 h to obtain isocyanate-based graphene.

[0012] In a preferred embodiment of the present invention, the ratio of graphite powder, sodium nitrate, concentrated sulfuric acid, potassium permanganate, deionized water and hydrogen peroxide solution in step b1 is 2g:1.5-2.5g:60-70mL:9-11g:130-150mL:30-40mL.

[0013] In a preferred embodiment of the present invention, the concentrated sulfuric acid in step b1 has a mass fraction of 98%; the hydrogen peroxide solution has a mass fraction of 30-35%; and the hydrochloric acid solution has a mass fraction of 5-6%.

[0014] In a preferred embodiment of the present invention, the ratio of propyltriethoxysilane isocyanate, anhydrous ethanol, deionized water and graphene oxide in step b2 is 3-5g: 80-85mL: 10-15mL: 1g.

[0015] In a preferred embodiment of the present invention, the hydrochloric acid solution in step b2 has a mass fraction of 10-15 mL.

[0016] Secondly, this application provides a method for preparing a high-strength, tough, self-healing modified polyurethane material, comprising the following steps: Step 1: Weigh out 20-25 parts of polytetramethylene ether glycol, 3-9 parts of DA-bonded Schiff base tetraol, 10-12 parts of isophorone diisocyanate, 0.04-0.06 parts of dibutyltin dilaurate, 0.5-1.3 parts of 4,4'-dithiodiphenylamine, 0.3-1.5 parts of isocyanate-based graphene, and 50-55 parts of tetrahydrofuran according to the following weight proportions, and set aside for later use; the polytetramethylene ether glycol is BASF PTMEG 2000; Step 2: Add polytetramethylene ether glycol, isophorone diisocyanate, dibutyltin dilaurate, and tetrahydrofuran to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 20-25℃ and 200-300 r / min for 10-20 min. Then, raise the temperature to 60-80℃ and continue stirring for 1-2 h. Add DA-bonded Schiff base tetraol and continue stirring for 2-4 h. Then, lower the temperature to 40-50℃ and add 4,4'-dithiodiphenylamine and continue stirring for 2-3 h. Then, add isocyanate-based graphene and continue stirring for 1-2 h. After the reaction is complete, pour the reaction product into a mold and place it in a vacuum drying oven at 70-80℃ for 20-30 h to obtain a high-strength, tough, self-healing modified polyurethane material.

[0017] The beneficial effects of this invention are: This invention discloses a high-strength, tough, self-healing modified polyurethane material and its preparation method. The method involves reacting polytetramethylene ether glycol, isophorone diisocyanate, dibutyltin dilaurate, and tetrahydrofuran with stirring. Then, DA-bonded Schiff base tetraol, 4,4'-dithiodiphenylamine, and isocyanate-based graphene are added, and the reaction continues with stirring. After the reaction is complete, the reaction product is poured into a mold and dried to obtain the high-strength, tough, self-healing modified polyurethane material. This preparation method uses polytetramethylene ether glycol and isophorone diisocyanate as the main raw materials to prepare the polyurethane material, and adds DA-bonded Schiff base tetraol to it. The participation of alkali tetraol in the reaction can enhance the crosslinking degree of polyurethane materials and endow them with self-healing properties. 4,4'-dithiodiphenylamine can further enhance its self-healing effect. Subsequently, the addition of isocyanate-based graphene can improve the mechanical properties of polyurethane materials, resulting in polyurethane materials with high strength, toughness, and self-healing properties. In practical applications, they exhibit good self-healing and long-term functional retention capabilities, significantly improving the tolerance of polyurethane materials to harsh environments or usage conditions, enhancing the reliability and service life of polyurethane materials in practical applications, and expanding their application range.

[0018] In the preparation of polyurethane materials, a DA-bonded Schiff base tetraol was first prepared. Using terephthalaldehyde and N-bromosuccinimide, N-bromosuccinimide acts as a brominating agent to introduce bromine atoms onto the benzene ring of terephthalaldehyde, yielding dibromo-terephthalaldehyde. Then, using dibromo-terephthalaldehyde and furfuryl alcohol, the bromine atom on the dibromo-terephthalaldehyde reacts with the hydroxyl group on furfuryl alcohol, introducing a furfuryl group, yielding difurfuryl-terephthalaldehyde. Next, using difurfuryl-terephthalaldehyde and N-phenylmaleimide, the furfuryl group on difurfuryl-terephthalaldehyde reacts with the maleimide on N-phenylmaleimide to form a DA bond structure, yielding DA-bonded terephthalaldehyde. Finally, using DA-bonded terephthalaldehyde and 2-amino-1,3-propanediol… In the reaction, the aldehyde group on terephthalaldehyde reacts with the amino group on 2-amino-1,3-propanediol to form a Schiff base structure, while introducing multiple hydroxyl groups to obtain a DA-bonded Schiff base tetraol. This DA-bonded Schiff base tetraol contains multiple hydroxyl groups in its molecular structure. Its participation in the polymerization process of polyurethane materials can enhance their crosslinking degree and improve their mechanical properties. Furthermore, both the introduced Schiff base structure and the DA bond structure are reversible dynamic covalent bonds, and their interaction with the disulfide bond in 4,4'-dithiodiphenylamine endows it with excellent self-healing properties. This gives the polyurethane material good self-healing and long-lasting functional retention capabilities, enhancing its reliability and service life in practical applications.

[0019] In the preparation of polyurethane materials, an isocyanate-based graphene was first prepared. Graphene oxide was prepared using graphite powder as a raw material, and then the graphene oxide was modified using propyltriethoxysilane. The siloxane on the propyltriethoxysilane was hydrolyzed to form silanol, which was then grafted onto the surface of the graphene oxide. At the same time, isocyanate groups were introduced to obtain isocyanate-based graphene. After modification, the isocyanate-based graphene can be uniformly dispersed inside the polyurethane material. The isocyanate groups can connect with the polyurethane material in the form of chemical bonds. Furthermore, the uniformly dispersed graphene sheets can form a nano-barrier, preventing the generation of microcracks and forcing the propagating microcracks to deflect, bypass, or branch, thereby extending the crack propagation path, consuming more energy, preventing further opening, and improving the mechanical properties of the polyurethane material. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1:

[0022] This embodiment describes a method for preparing a high-strength, tough, self-healing modified polyurethane material, comprising the following steps: Step S1: 10 mmol of terephthalaldehyde and 20 mL of 98% concentrated sulfuric acid were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred for 10 min at 20 °C and a stirring rate of 200 r / min. Then, 23 mmol of N-bromosuccinimide was added, and the mixture was heated to 70 °C and stirred for another 4 h. After the reaction was completed, the product was cooled to room temperature and poured into ice water. The mixture was then vacuum filtered, and the filter cake was added to dichloromethane. The product was then washed twice with 5% sodium bicarbonate solution and saturated sodium chloride solution, and dried with anhydrous sodium sulfate. The product was then vacuum filtered, and the solvent was removed by rotary evaporation of the filtrate to obtain dibromo-terephthalaldehyde. Step S2: 10 mmol dibromo-terephthalaldehyde, 20 mmol furfuryl alcohol, 25 mmol triethylamine and 70 mL N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 20 °C and 200 r / min for 10 min. Then the temperature was raised to 50 °C and the mixture was stirred for 3 h. After that, the temperature was raised to 90 °C and the mixture was stirred for 8 h. After the reaction was completed, the reaction product was cooled to room temperature and then filtered under vacuum. The solvent was removed by rotary evaporation of the filtrate to obtain difuryl-terephthalaldehyde. Step S3: 10 mmol of difurfuryl terephthalaldehyde, 20 mmol of N-phenylmaleimide and 70 mL of tetrahydrofuran were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 0 °C and 200 r / min for 30 min. Then the temperature was raised to 60 °C and the mixture was stirred for 10 h. After the reaction was completed, the reaction product was cooled to room temperature and then poured into petroleum ether. The mixture was then vacuum filtered. The filter cake was washed twice with methanol and then placed in a vacuum drying oven and dried at 60 °C for 2 h to obtain DA bond terephthalaldehyde. Step S4: 10 mmol of DA-bonded terephthalaldehyde, 20 mmol of 2-amino-1,3-propanediol, 25 mmol of potassium carbonate and 100 mL of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection, and the reaction was stirred at 20 °C and 200 r / min for 10 min. Then the temperature was raised to 80 °C and the reaction was stirred for 10 h. After the reaction was completed, the reaction product was cooled to room temperature, then vacuum filtered, and the solvent was removed by rotary evaporation of the filtrate to obtain DA-bonded Schiff base tetraol. Step S5: Add 2g of graphite powder, 1.5g of sodium nitrate, and 60mL of 98% concentrated sulfuric acid to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 0℃ and 200r / min for 2h. Then, raise the temperature to 15℃ and continue stirring for 1h. Add 9g of potassium permanganate and raise the temperature to 35℃ and continue stirring for 1h. Add 130mL of deionized water and continue stirring for 2h. Add 30mL of 30% hydrogen peroxide solution and continue stirring for 30min. After the reaction is complete, cool the reaction product to room temperature and centrifuge. Wash the precipitate twice with 5% hydrochloric acid solution and distilled water, and then place it in a vacuum drying oven and dry at 70℃ for 2h to obtain graphene oxide. Step S6: Add 3g of propyltriethoxysilane isocyanate, 80mL of anhydrous ethanol and 10mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 20℃ and 200r / min for 10min. Then adjust the pH to 4 with 10mL of hydrochloric acid solution and continue stirring for 30min. Then add 1g of graphene oxide and continue stirring at 60℃ for 5h. After the reaction is complete, cool the reaction product to room temperature, centrifuge, wash the precipitate twice with distilled water, and then place it in a vacuum drying oven and dry at 50℃ for 2h to obtain isocyanate-based graphene. Step S7: Weigh out 20 parts by weight of polytetramethylene ether glycol, 3 parts by weight of DA-bonded Schiff base tetraol, 10 parts by weight of isophorone diisocyanate, 0.04 parts by weight of dibutyltin dilaurate, 0.5 parts by weight of 4,4'-dithiodiphenylamine, 0.3 parts by weight of isocyanate-based graphene, and 50 parts by weight of tetrahydrofuran, and set aside; the polytetramethylene ether glycol is BASF PTMEG 2000; Step S8: Polytetramethylene ether glycol, isophorone diisocyanate, dibutyltin dilaurate, and tetrahydrofuran were added to a three-necked flask equipped with a stirrer and thermometer. The mixture was stirred at 20°C and a stirring rate of 200 r / min for 10 min. Then, the temperature was raised to 60°C and the mixture was stirred for 1 h. After that, DA-bonded Schiff base tetraol was added and the mixture was stirred for 2 h. Then, the temperature was lowered to 40°C and 4,4'-dithiodiphenylamine was added and the mixture was stirred for 2 h. After that, isocyanate-based graphene was added and the mixture was stirred for 1 h. After the reaction was completed, the reaction product was poured into a mold and then placed in a vacuum drying oven at 70°C for 20 h to obtain a high-strength and tough self-healing modified polyurethane material.

[0023] Example 2:

[0024] This embodiment describes a method for preparing a high-strength, tough, self-healing modified polyurethane material, comprising the following steps: Step S1: 10 mmol of terephthalaldehyde and 22 mL of 98% concentrated sulfuric acid were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred for 15 min at 22 °C and a stirring rate of 250 r / min. Then, 24 mmol of N-bromosuccinimide was added, and the mixture was heated to 72 °C and stirred for another 5 h. After the reaction was completed, the product was cooled to room temperature and poured into ice water. The mixture was then vacuum filtered, and the filter cake was added to dichloromethane. The mixture was then washed twice with 5.5% sodium bicarbonate solution and saturated sodium chloride solution, respectively. After drying with anhydrous sodium sulfate, the mixture was vacuum filtered, and the solvent was removed by rotary evaporation of the filtrate to obtain dibromo-terephthalaldehyde. Step S2: 10 mmol dibromo-terephthalaldehyde, 20 mmol furfuryl alcohol, 30 mmol triethylamine and 75 mL N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 22 °C and 250 r / min for 15 min. Then the temperature was raised to 55 °C and the mixture was stirred for 4 h. After that, the temperature was raised to 95 °C and the mixture was stirred for 9 h. After the reaction was completed, the reaction product was cooled to room temperature and then filtered under vacuum. The solvent was removed by rotary evaporation of the filtrate to obtain difuryl-terephthalaldehyde. Step S3: 10 mmol of difurfuryl terephthalaldehyde, 20 mmol of N-phenylmaleimide and 75 mL of tetrahydrofuran were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 3 °C and 250 r / min for 45 min. Then the temperature was raised to 65 °C and the mixture was stirred for 12 h. After the reaction was completed, the reaction product was cooled to room temperature and then poured into petroleum ether. The mixture was then vacuum filtered. The filter cake was washed twice with methanol and then placed in a vacuum drying oven and dried at 65 °C for 2.5 h to obtain DA bond terephthalaldehyde. Step S4: 10 mmol of DA-bonded terephthalaldehyde, 20 mmol of 2-amino-1,3-propanediol, 30 mmol of potassium carbonate and 110 mL of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection, and the reaction was stirred at 22 °C and 250 r / min for 15 min. Then the temperature was raised to 85 °C and the reaction was stirred for 12 h. After the reaction was completed, the reaction product was cooled to room temperature, then vacuum filtered, and the solvent was removed by rotary evaporation of the filtrate to obtain DA-bonded Schiff base tetraol. Step S5: Add 2g of graphite powder, 2g of sodium nitrate, and 65mL of 98% concentrated sulfuric acid to a three-necked flask equipped with a stirrer and thermometer. Stir and react for 2.5h at 3℃ and a stirring rate of 250r / min. Then, raise the temperature to 18℃ and continue stirring for 1.5h. Add 10g of potassium permanganate and raise the temperature to 38℃ and continue stirring for 1.5h. Add 140mL of deionized water and continue stirring for 2.5h. Add 35mL of 32% hydrogen peroxide solution and continue stirring for 35min. After the reaction is complete, cool the reaction product to room temperature, centrifuge, and wash the precipitate twice with 5.5% hydrochloric acid solution and distilled water. Then, place it in a vacuum drying oven and dry at 75℃ for 2.5h to obtain graphene oxide. Step S6: Add 4g of propyltriethoxysilane isocyanate, 82mL of anhydrous ethanol and 12mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 22℃ and 250r / min for 15min. Then adjust the pH to 4.5 with 12mL of hydrochloric acid solution and continue stirring for 40min. Then add 1g of graphene oxide and heat to 70℃ and continue stirring for 6h. After the reaction is completed, cool the reaction product to room temperature, centrifuge, wash the precipitate twice with distilled water, and then place it in a vacuum drying oven and dry at 55℃ for 2.5h to obtain isocyanate-based graphene. Step S7: Weigh out 22 parts by weight of polytetramethylene ether glycol, 6 parts by weight of DA-bonded Schiff base tetraol, 11 parts by weight of isophorone diisocyanate, 0.05 parts by weight of dibutyltin dilaurate, 0.9 parts by weight of 4,4'-dithiodiphenylamine, 0.9 parts by weight of isocyanate-based graphene, and 52 parts by weight of tetrahydrofuran, and set aside; the polytetramethylene ether glycol is BASF PTMEG 2000; Step S8: Polytetramethylene ether glycol, isophorone diisocyanate, dibutyltin dilaurate, and tetrahydrofuran were added to a three-necked flask equipped with a stirrer and thermometer. The mixture was stirred at 22°C and 250 r / min for 15 min. Then, the temperature was raised to 70°C and the mixture was stirred for 1.5 h. After that, DA-bonded Schiff base tetraol was added and the mixture was stirred for 3 h. Then, the temperature was lowered to 45°C and 4,4'-dithiodiphenylamine was added and the mixture was stirred for 2.5 h. After that, isocyanate-based graphene was added and the mixture was stirred for 1.5 h. After the reaction was completed, the reaction product was poured into a mold and then placed in a vacuum drying oven at 75°C for 25 h to obtain a high-strength and tough self-healing modified polyurethane material.

[0025] Example 3:

[0026] This embodiment describes a method for preparing a high-strength, tough, self-healing modified polyurethane material, comprising the following steps: Step S1: 10 mmol of terephthalaldehyde and 25 mL of 98% concentrated sulfuric acid were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred at 25°C and 300 r / min for 20 min. Then, 25 mmol of N-bromosuccinimide was added and the mixture was heated to 75°C and stirred for another 6 h. After the reaction was completed, the product was cooled to room temperature and poured into ice water. The mixture was then vacuum filtered, and the filter cake was added to dichloromethane. The product was then washed three times with 6% sodium bicarbonate solution and saturated sodium chloride solution. After drying with anhydrous sodium sulfate, the product was vacuum filtered, and the solvent was removed by rotary evaporation of the filtrate to obtain dibromo-terephthalaldehyde. Step S2: 10 mmol dibromo-terephthalaldehyde, 20 mmol furfuryl alcohol, 35 mmol triethylamine and 80 mL N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 25 °C and 300 r / min for 20 min. Then the temperature was raised to 60 °C and the mixture was stirred for 5 h. After that, the temperature was raised to 100 °C and the mixture was stirred for 10 h. After the reaction was completed, the reaction product was cooled to room temperature and then filtered under vacuum. The solvent was removed by rotary evaporation of the filtrate to obtain difuryl-terephthalaldehyde. Step S3: 10 mmol of difurfuryl terephthalaldehyde, 20 mmol of N-phenylmaleimide and 80 mL of tetrahydrofuran were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 5 °C and 300 r / min for 60 min. The temperature was then raised to 70 °C and the mixture was stirred for 15 h. After the reaction was completed, the reaction product was cooled to room temperature and then poured into petroleum ether. The mixture was then vacuum filtered. The filter cake was washed three times with methanol and then placed in a vacuum drying oven and dried at 70 °C for 3 h to obtain DA bond terephthalaldehyde. Step S4: 10 mmol of DA-bonded terephthalaldehyde, 20 mmol of 2-amino-1,3-propanediol, 35 mmol of potassium carbonate and 120 mL of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection, and the reaction was stirred at 25 °C and 300 r / min for 20 min. Then the temperature was raised to 90 °C and the reaction was stirred for 15 h. After the reaction was completed, the reaction product was cooled to room temperature, then vacuum filtered, and the solvent was removed by rotary evaporation of the filtrate to obtain DA-bonded Schiff base tetraol. Step S5: Add 2g of graphite powder, 2.5g of sodium nitrate, and 70mL of 98% concentrated sulfuric acid to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 5℃ and 300r / min for 3h. Then, raise the temperature to 20℃ and continue stirring for 2h. Add 11g of potassium permanganate and raise the temperature to 40℃ and continue stirring for 2h. Add 150mL of deionized water and continue stirring for 3h. Add 40mL of 35% hydrogen peroxide solution and continue stirring for 40min. After the reaction is complete, cool the reaction product to room temperature and centrifuge. Wash the precipitate three times with 6% hydrochloric acid solution and distilled water. Then place it in a vacuum drying oven and dry at 80℃ for 3h to obtain graphene oxide. Step S6: Add 5g of propyltriethoxysilane isocyanate, 85mL of anhydrous ethanol and 15mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 25℃ and 300r / min for 20min. Then adjust the pH to 5 with 15mL of hydrochloric acid solution and continue stirring for 50min. Then add 1g of graphene oxide and heat to 80℃ and continue stirring for 7h. After the reaction is completed, cool the reaction product to room temperature, centrifuge, wash the precipitate three times with distilled water, and then place it in a vacuum drying oven and dry at 60℃ for 3h to obtain isocyanate-based graphene. Step S7: Weigh out 25 parts by weight of polytetramethylene ether glycol, 9 parts by weight of DA-bonded Schiff base tetraol, 12 parts by weight of isophorone diisocyanate, 0.06 parts by weight of dibutyltin dilaurate, 1.3 parts by weight of 4,4'-dithiodiphenylamine, 1.5 parts by weight of isocyanate-based graphene, and 55 parts by weight of tetrahydrofuran, and set aside for later use; the polytetramethylene ether glycol is BASF PTMEG 2000; Step S8: Polytetramethylene ether glycol, isophorone diisocyanate, dibutyltin dilaurate, and tetrahydrofuran were added to a three-necked flask equipped with a stirrer and thermometer. The mixture was stirred and reacted at 25°C and a stirring rate of 300 r / min for 20 min. Then, the temperature was raised to 80°C and the mixture was stirred and reacted for 2 h. After that, DA-bonded Schiff base tetraol was added and the mixture was stirred and reacted for 4 h. Then, the temperature was lowered to 50°C and 4,4'-dithiodiphenylamine was added and the mixture was stirred and reacted for 3 h. After that, isocyanate-based graphene was added and the mixture was stirred and reacted for 2 h. After the reaction was completed, the reaction product was poured into a mold and then placed in a vacuum drying oven and dried at 80°C for 30 h to obtain a high-strength and tough self-healing modified polyurethane material.

[0027] Comparative Example 1: This comparative example illustrates a method for preparing a high-strength, tough, self-healing modified polyurethane material, comprising the following steps: Step S1: Weigh out 25 parts by weight of polytetramethylene ether glycol, 12 parts by weight of isophorone diisocyanate, 0.06 parts by weight of dibutyltin dilaurate, 1.3 parts by weight of 4,4'-dithiodiphenylamine, and 55 parts by weight of tetrahydrofuran, and set aside; the polytetramethylene ether glycol is BASF PTMEG 2000; Step S2: Polytetramethylene ether glycol, isophorone diisocyanate, dibutyltin dilaurate, and tetrahydrofuran were added to a three-necked flask equipped with a stirrer and thermometer. The mixture was stirred and reacted at 25°C and a stirring rate of 300 r / min for 20 min. Then, the temperature was raised to 80°C and the mixture was stirred and reacted for 2 h. After that, the temperature was lowered to 50°C and 4,4'-dithiodiphenylamine was added and the mixture was stirred and reacted for 3 h. After the reaction was completed, the reaction product was poured into a mold and then placed in a vacuum drying oven and dried at 80°C for 30 h to obtain a high-strength and tough self-healing modified polyurethane material.

[0028] Comparative Example 2: This comparative example illustrates a method for preparing a high-strength, tough, self-healing modified polyurethane material, comprising the following steps: Step S1: 10 mmol of terephthalaldehyde and 25 mL of 98% concentrated sulfuric acid were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred at 25°C and 300 r / min for 20 min. Then, 25 mmol of N-bromosuccinimide was added and the mixture was heated to 75°C and stirred for another 6 h. After the reaction was completed, the product was cooled to room temperature and poured into ice water. The mixture was then vacuum filtered, and the filter cake was added to dichloromethane. The product was then washed three times with 6% sodium bicarbonate solution and saturated sodium chloride solution. After drying with anhydrous sodium sulfate, the product was vacuum filtered, and the solvent was removed by rotary evaporation of the filtrate to obtain dibromo-terephthalaldehyde. Step S2: 10 mmol dibromo-terephthalaldehyde, 20 mmol furfuryl alcohol, 35 mmol triethylamine and 80 mL N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 25 °C and 300 r / min for 20 min. Then the temperature was raised to 60 °C and the mixture was stirred for 5 h. After that, the temperature was raised to 100 °C and the mixture was stirred for 10 h. After the reaction was completed, the reaction product was cooled to room temperature and then filtered under vacuum. The solvent was removed by rotary evaporation of the filtrate to obtain difuryl-terephthalaldehyde. Step S3: 10 mmol of difurfuryl terephthalaldehyde, 20 mmol of N-phenylmaleimide and 80 mL of tetrahydrofuran were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 5 °C and 300 r / min for 60 min. The temperature was then raised to 70 °C and the mixture was stirred for 15 h. After the reaction was completed, the reaction product was cooled to room temperature and then poured into petroleum ether. The mixture was then vacuum filtered. The filter cake was washed three times with methanol and then placed in a vacuum drying oven and dried at 70 °C for 3 h to obtain DA bond terephthalaldehyde. Step S4: 10 mmol of DA-bonded terephthalaldehyde, 20 mmol of 2-amino-1,3-propanediol, 35 mmol of potassium carbonate and 120 mL of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection, and the reaction was stirred at 25 °C and 300 r / min for 20 min. Then the temperature was raised to 90 °C and the reaction was stirred for 15 h. After the reaction was completed, the reaction product was cooled to room temperature, then vacuum filtered, and the solvent was removed by rotary evaporation of the filtrate to obtain DA-bonded Schiff base tetraol. Step S5: Weigh out 25 parts by weight of polytetramethylene ether glycol, 9 parts by weight of DA-bonded Schiff base tetraol, 12 parts by weight of isophorone diisocyanate, 0.06 parts by weight of dibutyltin dilaurate, 1.3 parts by weight of 4,4'-dithiodiphenylamine, and 55 parts by weight of tetrahydrofuran, and set aside; the polytetramethylene ether glycol is BASF PTMEG 2000; Step S6: Polytetramethylene ether glycol, isophorone diisocyanate, dibutyltin dilaurate, and tetrahydrofuran were added to a three-necked flask equipped with a stirrer and thermometer. The mixture was stirred and reacted at 25°C and a stirring rate of 300 r / min for 20 min. Then, the temperature was raised to 80°C and the mixture was stirred and reacted for 2 h. After that, DA-bonded Schiff base tetraol was added and the mixture was stirred and reacted for 4 h. Then, the temperature was lowered to 50°C and 4,4'-dithiodiphenylamine was added and the mixture was stirred and reacted for 3 h. After the reaction was completed, the reaction product was poured into a mold and then placed in a vacuum drying oven and dried at 80°C for 30 h to obtain a high-strength and tough self-healing modified polyurethane material.

[0029] Comparative Example 3: This comparative example illustrates a method for preparing a high-strength, tough, self-healing modified polyurethane material, comprising the following steps: Step S1: Add 2g of graphite powder, 2.5g of sodium nitrate, and 70mL of 98% concentrated sulfuric acid to a three-necked flask equipped with a stirrer and thermometer. Stir the mixture at 5℃ and a stirring rate of 300r / min for 3h. Then, raise the temperature to 20℃ and continue stirring for 2h. Next, add 11g of potassium permanganate and raise the temperature to 40℃ and continue stirring for 2h. Then, add 150mL of deionized water and continue stirring for 3h. Finally, add 40mL of 35% hydrogen peroxide solution and continue stirring for 40min. After the reaction is complete, cool the reaction product to room temperature and centrifuge. Wash the precipitate three times with 6% hydrochloric acid solution and distilled water. Then, place it in a vacuum drying oven and dry it at 80℃ for 3h to obtain graphene oxide. Step S2: Add 5g of propyltriethoxysilane isocyanate, 85mL of anhydrous ethanol and 15mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 25℃ and 300r / min for 20min. Then adjust the pH to 5 with 15mL of hydrochloric acid solution and continue stirring for 50min. Then add 1g of graphene oxide and heat to 80℃ and continue stirring for 7h. After the reaction is completed, cool the reaction product to room temperature, centrifuge, wash the precipitate three times with distilled water, and then place it in a vacuum drying oven and dry at 60℃ for 3h to obtain isocyanate-based graphene. Step S3: Weigh out 25 parts by weight of polytetramethylene ether glycol, 12 parts by weight of isophorone diisocyanate, 0.06 parts by weight of dibutyltin dilaurate, 1.3 parts by weight of 4,4'-dithiodiphenylamine, 1.5 parts by weight of isocyanate-based graphene, and 55 parts by weight of tetrahydrofuran, and set aside for later use; the polytetramethylene ether glycol is BASF PTMEG 2000; Step S4: Polytetramethylene ether glycol, isophorone diisocyanate, dibutyltin dilaurate, and tetrahydrofuran were added to a three-necked flask equipped with a stirrer and thermometer. The mixture was stirred and reacted at 25°C and a stirring rate of 300 r / min for 20 min. Then, the temperature was raised to 80°C and the mixture was stirred and reacted for 2 h. After that, the temperature was lowered to 50°C and 4,4'-dithiodiphenylamine was added and the mixture was stirred and reacted for 3 h. Then, isocyanate-based graphene was added and the mixture was stirred and reacted for 2 h. After the reaction was completed, the reaction product was poured into a mold and then placed in a vacuum drying oven and dried at 80°C for 30 h to obtain a high-strength and tough self-healing modified polyurethane material.

[0030] The high-strength and high-toughness self-healing modified polyurethane materials of Examples 1-3 and Comparative Examples 1-3 were tested for initial tensile strength according to GB / T 528-2009. The samples were cut in half from the middle and placed together naturally, and then placed in an oven at 100°C for 24 hours. The tensile strength after repair was measured again, and the self-healing efficiency was obtained by dividing the tensile strength after repair by the initial tensile strength and multiplying it by 100%. The tensile stress-strain curve was obtained according to GB / T 528-2009, and the toughness was obtained by calculating the area under the curve.

[0031] The test results are shown in the table below:

[0032] Referring to the data in the table above, and based on the comparison between Examples 1-3 and Comparative Examples 1-3, it can be seen that adding DA-bonded Schiff base tetraol and isocyanate-based graphene can improve the tensile strength and self-healing efficiency of polyurethane materials while maintaining high toughness. This results in polyurethane materials with advantages such as high strength, excellent self-healing effect, and good toughness.

[0033] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0034] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the protection scope of the present invention.

Claims

1. A high-strength, high-toughness, self-healing modified polyurethane material, characterized in that, Includes the following components by weight: 20-25 parts of polytetramethylene ether glycol, 3-9 parts of DA-bonded Schiff base tetraol, 10-12 parts of isophorone diisocyanate, 0.04-0.06 parts of dibutyltin dilaurate, 0.5-1.3 parts of 4,4'-dithiodiphenylamine, 0.3-1.5 parts of isocyanate-based graphene, and 50-55 parts of tetrahydrofuran; The DA-bonded Schiff base tetraol is prepared by the following steps: Step a1: Terephthalaldehyde and concentrated sulfuric acid are stirred and reacted, then N-bromosuccinimide is added and the reaction is continued. After the reaction is completed, the reaction product is cooled and poured into ice water. Then, it is vacuum filtered, and the filter cake is added to dichloromethane. After washing and drying, it is vacuum filtered again, and the filtrate is evaporated by rotary evaporation to obtain dibromo-terephthalaldehyde. Step a2: Dibromo-terephthalaldehyde, furfuryl alcohol, triethylamine and N,N-dimethylformamide were stirred and reacted. After the reaction was completed, the reaction product was cooled and then filtered under vacuum. The filtrate was evaporated by rotary evaporation to obtain difurfuryl-terephthalaldehyde. Step a3: Difurfural terephthalaldehyde, N-phenylmaleimide and tetrahydrofuran were stirred and reacted. After the reaction was completed, the reaction product was cooled and then poured into petroleum ether. After vacuum filtration, the filter cake was washed and dried to obtain DA bond terephthalaldehyde. Step a4: The DA-bonded terephthalaldehyde, 2-amino-1,3-propanediol, potassium carbonate, and N,N-dimethylformamide were stirred and reacted. After the reaction was completed, the reaction product was cooled, then vacuum filtered, and the filtrate was evaporated by rotary evaporation to obtain DA-bonded Schiff base tetraol.

2. The high-strength, high-toughness, self-healing modified polyurethane material according to claim 1, characterized in that, In step a1, the ratio of terephthalaldehyde, concentrated sulfuric acid, and N-bromosuccinimide is 10 mmol: 20-25 mL: 23-25 ​​mmol; the concentrated sulfuric acid has a mass fraction of 98%.

3. The high-strength, high-toughness, self-healing modified polyurethane material according to claim 1, characterized in that, The ratio of dibromo-terephthalaldehyde, furfuryl alcohol, triethylamine, and N,N-dimethylformamide used in step a2 is 10 mmol: 20 mmol: 25-35 mmol: 70-80 mL.

4. The high-strength, high-toughness, self-healing modified polyurethane material according to claim 1, characterized in that, The ratio of difurfuryl terephthalaldehyde, N-phenylmaleimide and tetrahydrofuran in step a3 is 10 mmol: 20 mmol: 70-80 mL.

5. The high-strength, high-toughness, self-healing modified polyurethane material according to claim 1, characterized in that, In step a4, the ratio of the amounts of DA bond terephthalaldehyde, 2-amino-1,3-propanediol, potassium carbonate, and N,N-dimethylformamide is 10 mmol: 20 mmol: 25-35 mmol: 100-120 mL.

6. The high-strength, high-toughness, self-healing modified polyurethane material according to claim 1, characterized in that, The isocyanate-based graphene is prepared by the following steps: Step b1: Graphite powder, sodium nitrate and concentrated sulfuric acid are stirred and reacted. Then potassium permanganate, deionized water and hydrogen peroxide solution are added and the reaction is continued. After the reaction is completed, the reaction product is cooled, centrifuged, and the precipitate is washed and dried to obtain graphene oxide. Step b2: Propyltriethoxysilane isocyanate, anhydrous ethanol, and deionized water are stirred and reacted. Then, the pH is adjusted with hydrochloric acid solution, and graphene oxide is added and the reaction is stirred and continued. After the reaction is completed, the reaction product is cooled, centrifuged, and the precipitate is washed and dried to obtain isocyanate-based graphene.

7. The high-strength, high-toughness, self-healing modified polyurethane material according to claim 6, characterized in that, In step b1, the ratio of graphite powder, sodium nitrate, concentrated sulfuric acid, potassium permanganate, deionized water, and hydrogen peroxide solution is 2g:1.5-2.5g:60-70mL:9-11g:130-150mL:30-40mL; the concentrated sulfuric acid has a mass fraction of 98%; and the hydrogen peroxide solution has a mass fraction of 30-35%.

8. The high-strength, high-toughness, self-healing modified polyurethane material according to claim 6, characterized in that, In step b2, the ratio of propyltriethoxysilane isocyanate, anhydrous ethanol, deionized water, and graphene oxide is 3-5g: 80-85mL: 10-15mL: 1g; and the mass fraction of the hydrochloric acid solution is 10-15mL.

9. A method for preparing a high-strength, tough, self-healing modified polyurethane material as described in any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Weigh out 20-25 parts of polytetramethylene ether glycol, 3-9 parts of DA-bonded Schiff base tetraol, 10-12 parts of isophorone diisocyanate, 0.04-0.06 parts of dibutyltin dilaurate, 0.5-1.3 parts of 4,4'-dithiodiphenylamine, 0.3-1.5 parts of isocyanate-based graphene, and 50-55 parts of tetrahydrofuran according to the following weight proportions, and set aside for later use; the polytetramethylene ether glycol is BASF PTMEG 2000; Step 2: Add polytetramethylene ether glycol, isophorone diisocyanate, dibutyltin dilaurate, and tetrahydrofuran to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 20-25℃ and 200-300 r / min for 10-20 min. Then, raise the temperature to 60-80℃ and continue stirring for 1-2 h. Add DA-bonded Schiff base tetraol and continue stirring for 2-4 h. Then, lower the temperature to 40-50℃ and add 4,4'-dithiodiphenylamine and continue stirring for 2-3 h. Then, add isocyanate-based graphene and continue stirring for 1-2 h. After the reaction is complete, pour the reaction product into a mold and place it in a vacuum drying oven at 70-80℃ for 20-30 h to obtain a high-strength, tough, self-healing modified polyurethane material.

Images