A toughened polyurethane based on double non-covalent interaction and its preparation method and application

Abstract

The present invention provides a toughened polyurethane based on dual non-covalent interactions, a preparation method thereof, and applications thereof. The present invention belongs to the technical field of supramolecular polymers. The preparation method comprises preparing a monodentate pyridine ligand compound having a crown ether structure, and preparing a polyurethane containing a tridentate pyridine ligand; conducting a coordination reaction between the polyurethane containing the tridentate pyridine ligand and palladium acetate to obtain a palladium-coordinated polyurethane; reacting the palladium-coordinated polyurethane with the monodentate pyridine ligand compound having a crown ether structure to obtain a palladium-coordinated polyurethane having a crown ether structure; and then reacting the palladium-coordinated polyurethane with a double-terminal secondary ammonium salt to obtain the toughened polyurethane based on dual non-covalent interactions. The toughened polyurethane of the present invention has two non-covalent interactions, namely host-guest recognition and metal coordination, which can synergistically toughen the polyurethane and impart good dynamics and mechanical properties to the polyurethane network.

Description

Technical Field

[0001] The invention belongs to the technical field of supramolecular polymers, and particularly relates to a toughened polyurethane based on double non-covalent interactions, a preparation method and an application thereof. Background Art

[0002] Supramolecular polymers (SPs) are an emerging class of polymers. Unlike traditional covalent polymers (CPs), supramolecular polymers are composed of monomeric units connected by non-covalent bonds. These non-covalent interactions include van der Waals forces, hydrogen bonds, Coulombic forces or ionic interactions, π-π stacking, metal coordination, halogen bonds, and host-guest interactions. Due to the presence of non-covalent bonds, supramolecular polymers have great potential in stimuli-responsiveness, self-adaptation, and self-healing properties, but this is accompanied by poor mechanical stability. Therefore, combining covalent and supramolecular polymers through appropriate interactions is a promising strategy for producing high-performance elastomers.

[0003] Weaving is one of humanity's oldest arts. The highly ordered warp and weft threads work synergistically, endowing woven materials with unique topological structures and rich mechanical behaviors. Inspired by this, researchers have attempted to introduce woven topology into polymer science, developing a new class of polymer materials with novel topological structures: woven polymers. Woven polymers are polymer networks constructed with woven nodes serving as crosslinks. Therefore, utilizing woven technology to achieve synergistic effects between covalent and supramolecular polymers is crucial for improving the performance of traditional polymer materials.

[0004] Traditional polyurethane elastomers suffer from poor mechanical strength and insufficient toughness, limiting their applications. However, introducing non-covalent bonds into polyurethane systems can impart superior toughness and dynamic properties. By combining supramolecular polymers with traditional covalent polymers through braiding technology, a toughened polyurethane with metal coordination and host-guest recognition can be constructed, offering new insights into the design and construction of functionalized polymer materials. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention aims to provide a toughened polyurethane based on double non-covalent interactions, and a preparation method and application thereof.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides a method for preparing a toughened polyurethane based on dual non-covalent interactions, the method comprising the following steps:

[0008] (1) Compound 1 and compound 2 react to obtain a monodentate pyridine ligand compound 3 having a crown ether structure, as shown in the following reaction formula:

[0009] ;

[0010] (2) 4-Aminomethylbenzyl alcohol reacts with pyridine-2,6-dicarboxylic acid to obtain compound 4. The reaction formula is as follows:

[0011] ;

[0012] (3) Polytetrahydrofuran, compound 4 and diisocyanate react, and then a chain extender is added to react to obtain a polyurethane containing a tridentate pyridine ligand;

[0013] (4) Coordinating the polyurethane containing the tridentate pyridine ligand with palladium acetate to obtain a palladium-coordinated polyurethane;

[0014] (5) reacting the palladium-coordinated polyurethane obtained in step (4) with compound 3 to obtain a palladium-coordinated polyurethane having a crown ether structure;

[0015] (6) reacting the palladium-coordinated polyurethane having a crown ether structure obtained in step (5) with a double-terminal secondary ammonium salt to obtain the toughened polyurethane based on double non-covalent interaction.

[0016] The present invention describes a toughened polyurethane based on dual non-covalent interactions, exhibiting excellent mechanical properties and promising potential in the field of high-performance polymer materials. The introduction of crown ethers as macrocyclic hosts into polyurethane systems not only forms a supramolecular network with secondary ammonium salts, imparting excellent dynamics and toughness to the polyurethane while increasing its stability, but also utilizes a weaving technique to combine supramolecular polymers with traditional covalent polymers to create a toughened polyurethane that utilizes both metal coordination and host-guest recognition, offering a novel approach to the design and construction of functionalized polymer materials.

[0017] In the present invention, two non-covalent interactions, namely, host-guest recognition and metal coordination between crown ether and secondary ammonium salt, are introduced into the polyurethane system, which can endow the polyurethane with good toughness and dynamic properties.

[0018] Preferably, the molar ratio of compound 1 to compound 2 in step (1) is (2.0-5.0):1, for example, 2.0:1, 2.2:1, 2.5:1, 2.8:1, 3:1, 3.3:1, 3.5:1, 3.8:1, 4:1, 4.3:1, 4.5:1, 4.8:1 or 5:1.

[0019] Preferably, the reaction in step (1) is carried out in the presence of an alkaline substance.

[0020] Preferably, the alkaline substance is selected from any one of potassium carbonate, cesium carbonate or potassium bicarbonate, more preferably potassium carbonate.

[0021] Preferably, the molar ratio of the compound 2 to the alkaline substance in step (1) is 1:(3.0-8.0), for example, 1:3.0, 1:3.3, 1:3.5, 1:3.8, 1:4, 1:4.5, 1:4.8, 1:5, 1:5.5, 1:5.8, 1:6, 1:6.5, 1:6.8, 1:7, 1:7.5, 1:7.8, 1:8, etc.

[0022] Preferably, the reaction in step (1) is carried out in an organic solvent, and the organic solvent is selected from any one or a combination of at least two of N,N-dimethylformamide, acetonitrile or dichloromethane, and is more preferably N,N-dimethylformamide.

[0023] Preferably, the reaction in step (1) is carried out under reflux.

[0024] Preferably, the reaction time of step (1) is 15 to 30 hours, for example, 15 hours, 18 hours, 20 hours, 23 hours, 25 hours, 28 hours or 30 hours.

[0025] In the present invention, after the reaction in step (1) is completed, filtration, concentration, and column chromatography purification are performed to obtain a monodentate pyridine ligand compound 3 having a crown ether structure.

[0026] The purification is performed by separation and purification using silica gel column chromatography, wherein the eluent of the silica gel column chromatography is a mixture of dichloromethane and methanol in a volume ratio of 15:1.

[0027] Preferably, the molar ratio of 4-aminomethylbenzyl alcohol to pyridine-2,6-dicarboxylic acid in step (2) is 1:(2.0-5.0), for example, 1:2.0, 1:2.3, 1:2.5, 1:2.8, 1:3.0, 1:3.5, 1:3.8, 1:4.0, 1:4.3, 1:4.5, 1:4.8 or 1:5.

[0028] Preferably, the reaction in step (2) is carried out in the presence of an activator, and the activator is selected from 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC).

[0029] Preferably, the reaction in step (2) is carried out in the presence of a catalyst, and the catalyst is selected from 4-dimethylaminopyridine (DMAP).

[0030] Preferably, the reaction in step (2) is carried out at room temperature.

[0031] In the present invention, the room temperature refers to a temperature of 15-35°C, such as 15°C, 18°C, 20°C, 25°C, 28°C, 30°C, 33°C or 35°C.

[0032] Preferably, the reaction time in step (2) is 12 to 24 hours, for example, 12 hours, 15 hours, 18 hours, 20 hours or 23 hours.

[0033] Preferably, the reaction in step (2) is carried out in a solvent selected from any one of dichloromethane, acetonitrile or N,N-dimethylformamide, or a combination of at least two thereof.

[0034] Preferably, the number average molecular weight of the polytetrahydrofuran in step (3) is 500-3000, for example, 500, 600, 800, 1000, 1300, 1500, 1800, 2000, 2300, 2500, 2800 or 3000.

[0035] Preferably, the diisocyanate in step (3) includes any one of isophorone diisocyanate, hexamethylene diisocyanate or toluene diisocyanate, or a combination of at least two thereof.

[0036] Preferably, the molar ratio of the polytetrahydrofuran to the chain extender in step (3) is (1.0-2.0):1, for example, 1:1, 1.2:1, 1.4:1, 1.5:1, 1.6:1, 1.8:1 or 2:1.

[0037] Preferably, the molar ratio of the compound 4 to the chain extender in step (3) is (0.001-0.1):1, for example, 0.001:1, 0.003:1, 0.005:1, 0.008:1, 0.01:1, 0.03:1, 0.05:1, 0.08:1 or 0.1:1.

[0038] Preferably, the molar ratio of the diisocyanate to the chain extender in step (3) is (2.0-3.0):1, for example, 2.0:1, 2.2:1, 2.5:1, 2.8:1 or 3:1.

[0039] Preferably, the reaction of polytetrahydrofuran, compound 4 and diisocyanate in step (3) is carried out under nitrogen protection.

[0040] Preferably, the reaction of polytetrahydrofuran, compound 4 and diisocyanate in step (3) is carried out in the presence of a catalyst, and the catalyst is preferably dibutyltin dilaurate.

[0041] Preferably, the reaction of polytetrahydrofuran, compound 4 and diisocyanate in step (3) is carried out at room temperature (15-35°C, for example, 15°C, 18°C, 20°C, 25°C, 28°C, 30°C, 33°C or 35°C).

[0042] Preferably, the reaction time of the polytetrahydrofuran, compound 4 and diisocyanate in step (3) is 12 to 36 hours, for example, 12 hours, 18 hours, 20 hours, 22 hours, 24 hours, 28 hours, 30 hours, 33 hours or 36 hours.

[0043] Preferably, the reaction of polytetrahydrofuran, compound 4 and diisocyanate in step (3) is carried out in an organic solvent, and the organic solvent is selected from any one of tetrahydrofuran, dichloromethane or N,N-dimethylformamide, or a combination of at least two thereof.

[0044] Preferably, the temperature of the reaction after adding the chain extender in step (3) is 30 to 80 degrees Celsius, for example, 30 degrees Celsius, 35 degrees Celsius, 40 degrees Celsius, 45 degrees Celsius, 50 degrees Celsius, 55 degrees Celsius, 60 degrees Celsius, 65 degrees Celsius, 70 degrees Celsius, 75 degrees Celsius or 80 degrees Celsius, more preferably 30 to 60 degrees Celsius.

[0045] Preferably, the reaction time after adding the chain extender in step (3) is 12 to 36 hours, for example, 12 hours, 18 hours, 20 hours, 22 hours, 24 hours, 28 hours, 30 hours, 33 hours or 36 hours.

[0046] Preferably, the chain extender added in step (3) is any one of 1,4-butanediol, ethylene glycol or triethylene glycol, or a combination of at least two thereof, and more preferably 1,4-butanediol.

[0047] In the present invention, after the reaction of adding the chain extender in step (3) is completed, the solvent is evaporated to obtain a polyurethane containing a tridentate pyridine ligand.

[0048] Preferably, the molar ratio of the polyurethane containing the tridentate pyridine ligand to palladium acetate in step (4) is 1:(1.0-6.0), for example, 1:1.0, 1:1.5, 1:2.0, 1:2.5, 1:3.0, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, etc., and more preferably 1:(1.0-3.0).

[0049] Preferably, the reaction in step (4) is carried out at room temperature (15-35°C, such as 15°C, 18°C, 20°C, 25°C, 28°C, 30°C, 33°C or 35°C).

[0050] Preferably, the reaction time of step (4) is 12 to 36 hours, for example, 12 hours, 18 hours, 20 hours, 22 hours, 24 hours, 28 hours, 30 hours, 33 hours or 36 hours, more preferably 24 to 36 hours.

[0051] Preferably, the specific operation of the reaction in step (4) is: adding palladium acetate to a dichloromethane, acetonitrile, and tetrahydrofuran solution of the polyurethane containing the tridentate pyridine ligand to react to obtain the palladium-coordinated polyurethane.

[0052] Preferably, the molar ratio of the palladium-coordinated polyurethane to compound 3 in step (5) is 1:(0.5-2.0), for example, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8 or 1:2.

[0053] Preferably, the reaction temperature in step (5) is 25 to 40 degrees Celsius, for example, 25 degrees Celsius, 28 degrees Celsius, 30 degrees Celsius, 35 degrees Celsius or 40 degrees Celsius, and the reaction time is 8 to 18 hours, for example, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours or 18 hours.

[0054] Preferably, the molar ratio of the palladium-coordinated polyurethane with a crown ether structure to the double-terminated secondary ammonium salt in step (6) is 1:(1.0-2.0), such as 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8 or 1:2.

[0055] Preferably, the reaction temperature in step (6) is 25 to 40 degrees Celsius, for example, 25 degrees Celsius, 28 degrees Celsius, 30 degrees Celsius, 35 degrees Celsius or 40 degrees Celsius, and the reaction time is 12 to 24 hours, for example, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours.

[0056] In the present invention, after the reaction in step (6) is completed, the solvent is evaporated to obtain the toughened polyurethane based on double non-covalent interaction.

[0057] The present invention introduces two non-covalent interactions, host-guest recognition and metal coordination, into the polyurethane network, which not only gives the polyurethane a unique topological structure, but also gives the polyurethane excellent mechanical properties.

[0058] In the present invention, the polyurethane network synergistically toughened by dual non-covalent interactions has a unique topological structure, is a combination of supramolecules and polymers, and is a very important type of elastomeric material.

[0059] In the present invention, host-guest recognition between the crown ether and the secondary ammonium salt forms a supramolecular polymer network. Braided nodes formed by metal coordination serve as connections between the covalent polymer and the supramolecular polymer, promoting the synergistic effect of the two components, thereby forming a strong and tough braided polymer network.

[0060] The dual non-covalent interactions of the present invention make the woven polymer network a highly dynamic network and endow the polyurethane with excellent toughness and strength, laying a solid foundation for dynamic topological polymer materials.

[0061] On the other hand, the present invention provides a toughened polyurethane based on dual non-covalent interactions prepared by the preparation method described above.

[0062] On the other hand, the present invention provides the use of the toughened polyurethane based on double non-covalent interaction in the synthesis of functional polymer materials.

[0063] Preferably, the functional polymer material is an elastomer.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] The present invention provides a polyurethane with excellent performance and mild synthesis conditions and synergistic toughening through dual non-covalent interactions. The dual non-covalent interactions are metal coordination and host-guest recognition. The presence of the two non-covalent interactions gives the polyurethane excellent mechanical properties, and has considerable application potential in the field of high-performance polymer materials.

[0066] The double non-covalent interaction synergistic toughening polyurethane provided by the present invention has a Young's modulus of 27.5 MPa, a breaking strength of 15.8 MPa, an elongation at break of 1279%, and a toughness of 142 MJ / m when the addition amount of the braided node is 1 mol%. 3 The Young's modulus of polyurethane without the introduction of double non-covalent interaction is only 14.6MPa, the breaking strength is only 5.57MP, the breaking elongation is only 628%, and the toughness is only 23.4MJ / m 3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 For compound 3 1 H NMR spectrum.

[0068] Figure 2 For compound 4 1 H NMR spectrum.

[0069] Figure 3 : is the GPC graph of WPN in the embodiment, wherein the triangle at the peak position represents the range selected for peak area integration, and the vertical line above the peak represents the selection of the peak apex.

[0070] Figure 4 is the TGA curve of WPN in the embodiment.

[0071] Figure 5Tensile stress-strain curves of CP-1, CP-3, and WPN in Examples.

[0072] Figure 6 These are the cyclic tensile test curves of CP-1, CP-3 and WPN in the examples. DETAILED DESCRIPTION

[0073] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are only provided to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0074] The raw materials involved in the following examples and comparative examples are as follows:

[0075] The structure of compound 3 is shown below, and its synthesis method includes the following steps:

[0076]

[0077] 1.7 g of compound 1 and 0.49 g of compound 2 were dissolved in 80 mL of N,N-dimethylformamide, and 0.9 g of potassium carbonate was added. After stirring at 85°C for 20 h, the reaction mixture was cooled to room temperature, filtered, and concentrated under reduced pressure to obtain a crude product. The crude product was purified by flash column chromatography (eluent: dichloromethane / methanol, volume ratio = 15:1) to obtain compound 3.

[0078] The H NMR spectrum of compound 3 is as follows Figure 1 shown.

[0079] The structure of compound 4 is shown below, and its synthesis method includes the following steps:

[0080]

[0081] 1.8 g of 4-aminomethylbenzyl alcohol, 3.5 g of EDC·HCl, and 1.5 g of DMAP were dissolved in 70 mL of dichloromethane, and 1 g of pyridine-2,6-dicarboxylic acid was added. The mixture was stirred at room temperature overnight and purified by column chromatography (eluent: dichloromethane / methanol, volume ratio = 20:1) to obtain compound 4.

[0082] The H NMR spectrum of compound 4 is as follows Figure 2 shown.

[0083] The epoxy resin is epoxy resin E51;

[0084] Polytetrahydrofuran: Kedao CD114526, number average molecular weight 2000;

[0085] Example 1

[0086] This embodiment provides a toughened polyurethane based on dual non-covalent interactions, and the preparation method thereof comprises the following steps:

[0087] A 5 mL tetrahydrofuran solution of 6 g polytetrahydrofuran, 17 mg compound 4, 1.41 g hexamethylene diisocyanate, and 10 mg dibutyltin dilaurate was reacted at room temperature under nitrogen for 12 h. Then, 0.3 g 1,4-butanediol was added and the reaction was continued at 50 °C for 15 h. Then, 10 mg palladium acetate was added and the reaction was continued at 25 °C for 12 h. Then, 45.7 mg compound 3 was added and the mixture was stirred at 25 °C for 12 h. Then, 30 mg of a double-terminated secondary ammonium salt was added and the mixture was stirred at 25 °C for 12 h. The reaction was terminated and the solvent was evaporated to obtain a toughened polyurethane WPN based on dual non-covalent interactions.

[0088] Example 2

[0089] This embodiment provides a toughened polyurethane based on dual non-covalent interactions, and the preparation method thereof comprises the following steps:

[0090] A 5 mL tetrahydrofuran solution of 5 g polytetrahydrofuran, 17 mg compound 4, 1.41 g hexamethylene diisocyanate, and 10 mg dibutyltin dilaurate was reacted at room temperature under nitrogen for 24 h. Then, 0.3 g 1,4-butanediol was added and the reaction was continued at 60 °C for 24 h. Then, 10 mg palladium acetate was added and the reaction was continued at 25 °C for 30 h. Then, 45.7 mg compound 3 was added and the mixture was stirred at 25 °C for 8 h. Then, 60 mg of a double-terminal secondary ammonium salt was added and the mixture was stirred at 25 °C for 24 h. The reaction was terminated and the solvent was evaporated to obtain a toughened polyurethane WPN based on dual non-covalent interactions.

[0091] Example 3

[0092] This embodiment provides a toughened polyurethane based on dual non-covalent interactions, and the preparation method thereof comprises the following steps:

[0093] A 10 mL tetrahydrofuran solution of 9 g polytetrahydrofuran, 34 mg compound 4, 1.1 g hexamethylene diisocyanate, and 10 mg dibutyltin dilaurate was reacted at room temperature under nitrogen for 12 h. Then, 0.3 g 1,4-butanediol was added and the reaction was continued at 80 °C for 12 h. 20 mg palladium acetate was added and the reaction was continued at 25 °C for 36 h. 91.2 mg compound 3 was added and stirred at 30 °C for 18 h. 60 mg of a double-terminal secondary ammonium salt was added and stirred at 40 °C for 12 h. The reaction was terminated and the solvent was evaporated to obtain a toughened polyurethane WPN based on dual non-covalent interactions.

[0094] Example 4

[0095] This embodiment provides a toughened polyurethane based on dual non-covalent interactions, and the preparation method thereof comprises the following steps:

[0096] A 10 mL tetrahydrofuran solution of 8 g polytetrahydrofuran, 34 mg compound 4, 1.43 g hexamethylene diisocyanate, and 10 mg dibutyltin dilaurate was reacted at room temperature under nitrogen for 3 h. Then, 0.3 g 1,4-butanediol was added and the reaction was continued at 80 °C for 12 h. Then, 20 mg palladium acetate was added and the reaction was continued at 25 °C for 36 h. Then, 91.2 mg compound 3 was added and the mixture was stirred at 40 °C for 12 h. Then, 120 mg of a double-terminal secondary ammonium salt was added and the mixture was stirred at 40 °C for 24 h. The reaction was terminated and the solvent was evaporated to obtain a toughened polyurethane WPN based on dual non-covalent interactions.

[0097] Example 5

[0098] This embodiment provides a toughened polyurethane based on dual non-covalent interactions, and the preparation method thereof comprises the following steps:

[0099] A 10 mL tetrahydrofuran solution of 12 g polytetrahydrofuran, 105 mg compound 4, 1.45 g hexamethylene diisocyanate, and 10 mg dibutyltin dilaurate was reacted at room temperature under nitrogen for 3 h. Then, 0.3 g 1,4-butanediol was added and the reaction was continued at 30 °C for 36 h. Then, 60 mg palladium acetate was added and the reaction was continued at 25 °C for 12 h. Then, 281 mg compound 3 was added and the mixture was stirred at 25 °C for 18 h. Then, 190 mg of a double-terminal secondary ammonium salt was added and the mixture was stirred at 25 °C for 12 h. The reaction was terminated and the solvent was evaporated to obtain a toughened polyurethane WPN based on dual non-covalent interactions.

[0100] Example 6

[0101] This embodiment provides a toughened polyurethane based on dual non-covalent interactions, and the preparation method thereof comprises the following steps:

[0102] A 10 mL tetrahydrofuran solution of 10 g polytetrahydrofuran, 105 mg compound 4, 1.45 g hexamethylene diisocyanate, and 10 mg dibutyltin dilaurate was reacted at room temperature for 3 h under nitrogen protection. Then, 0.3 g 1,4-butanediol was added and the reaction was continued at 50 °C for 24 h. Then, 60 mg palladium acetate was added and the reaction was continued at 25 °C for 12 h. Then, 281 mg compound 3 was added and the mixture was stirred at 35 °C for 12 h. Then, 380 mg of a double-terminal secondary ammonium salt was added and the mixture was stirred at 40 °C for 12 h. The reaction was terminated and the solvent was evaporated to obtain a toughened polyurethane WPN based on dual non-covalent interactions.

[0103] Comparative Example 1

[0104] This embodiment provides a toughened polyurethane based on dual non-covalent interactions, and the preparation method thereof comprises the following steps:

[0105] A 10 mL tetrahydrofuran solution of 9 g polytetrahydrofuran, 34 mg compound 4, 1.1 g hexamethylene diisocyanate, and 10 mg dibutyltin dilaurate was reacted at room temperature under nitrogen for 12 h. Then, 0.3 g 1,4-butanediol was added and the reaction was continued at 80 °C for 12 h. After the reaction was terminated, the solvent was evaporated to obtain a toughened polyurethane CP-1.

[0106] Comparative Example 2

[0107] This embodiment provides a toughened polyurethane based on dual non-covalent interactions, and the preparation method thereof comprises the following steps:

[0108] A 10 mL tetrahydrofuran solution of 9 g polytetrahydrofuran, 34 mg compound 4, 1.1 g hexamethylene diisocyanate, and 10 mg dibutyltin dilaurate was reacted at room temperature under nitrogen for 12 h. Then, 0.3 g 1,4-butanediol was added and the reaction was continued at 80 °C for 12 h. Then, 20 mg palladium acetate was added and the reaction was continued at 25 °C for 36 h. Then, 91.2 mg compound 3 was added and stirred at 30 °C for 18 h. The reaction was terminated and the solvent was evaporated to obtain a toughened polyurethane CP-3.

[0109] Figure 3 The GPC spectrum of WPN prepared in Example 4 is Figure 3 It can be seen that the number average molecular weight of WPN is 54 kDa.

[0110] Figure 4 This is the thermogravimetric curve of WPN prepared in Example 4. WPN begins to decompose at a high temperature above 250°C, indicating that this toughened polyurethane based on dual non-covalent interactions has good thermal stability.

[0111] Figure 5 The stress-strain curves of WPN prepared in Example 4, CP-1 prepared in Comparative Example 1, and CP-3 prepared in Comparative Example 2 at a stretching rate of 100 mm / min are shown in FIG. Figure 5 As shown, CP-3 exhibits superior fracture strength and toughness to CP-1, demonstrating the importance of metal coordination in the polymer. WPN exhibits the best fracture strength and toughness of the three, suggesting that the combined effects of metal coordination and host-guest recognition, two non-covalent interactions, contribute to the improved mechanical properties of the polyurethane.

[0112] Figure 5 The cyclic tensile curves of WPN prepared in Example 24, CP-1 prepared in Comparative Example 1, and CP-3 prepared in Comparative Example 2 at a tensile rate of 100 mm / min are shown in FIG. Figure 6 As shown in the figure, the hysteresis loop area of ​​WPN is much larger than that of CP-1 and CP-3, indicating that the synergistic effect of metal coordination and host-guest recognition gives polyurethane good energy dissipation ability.

[0113] The applicant states that while the above-described embodiments illustrate the polyurethanes, their preparation methods, and applications, the present invention is not limited to the aforementioned process steps, nor does it necessarily rely on these process steps for implementation. Persons skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a toughened polyurethane based on dual non-covalent interactions, characterized in that: The preparation method comprises the following steps: (1) Compound 1 and compound 2 react to obtain a monodentate pyridine ligand compound 3 having a crown ether structure, as shown in the following reaction formula: ； (2) 4-Aminomethylbenzyl alcohol reacts with pyridine-2,6-dicarboxylic acid to obtain compound 4. The reaction formula is as follows: ； (3) Polytetrahydrofuran, compound 4 and diisocyanate react, and then a chain extender is added to obtain a polyurethane containing a tridentate pyridine ligand; (4) Coordinating the polyurethane containing the tridentate pyridine ligand with palladium acetate to obtain a palladium-coordinated polyurethane; (5) reacting the palladium-coordinated polyurethane obtained in step (4) with compound 3 to obtain a palladium-coordinated polyurethane having a crown ether structure; (6) reacting the palladium-coordinated polyurethane having a crown ether structure obtained in step (5) with a double-terminal secondary ammonium salt to obtain the toughened polyurethane based on double non-covalent interaction.

2. The method for preparing a toughened polyurethane based on dual non-covalent interactions according to claim 1, characterized in that: The molar ratio of compound 1 to compound 2 in step (1) is (2.0-5.0):1; The reaction in step (1) is carried out in the presence of an alkaline substance; the alkaline substance is selected from any one of potassium carbonate, cesium carbonate or potassium bicarbonate; The molar ratio of the compound 2 to the alkaline substance in step (1) is 1:(3.0-8.0); The reaction in step (1) is carried out in an organic solvent, wherein the organic solvent is selected from any one or a combination of at least two of N,N-dimethylformamide, acetonitrile or dichloromethane; The reaction in step (1) is carried out under reflux for 15 to 30 hours.

3. The method for preparing a toughened polyurethane based on dual non-covalent interactions according to claim 1, characterized in that: The reaction in step (2) is carried out in the presence of an activator, wherein the activator is selected from 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride; The reaction in step (2) is carried out in the presence of a catalyst, and the catalyst is selected from 4-dimethylaminopyridine; The reaction in step (2) is carried out at room temperature and the reaction time is 12 to 24 hours; The reaction in step (2) is carried out in a solvent, and the solvent is selected from any one of dichloromethane, acetonitrile, and N,N-dimethylformamide.

4. The method for preparing a toughened polyurethane based on dual non-covalent interactions according to claim 1, characterized in that: The number average molecular weight of the polytetrahydrofuran in step (3) is 500 to 3000; The diisocyanate in step (3) includes any one of isophorone diisocyanate, hexamethylene diisocyanate or toluene diisocyanate, or a combination of at least two thereof; The molar ratio of the polytetrahydrofuran to the chain extender in step (3) is (1.0-2.0):1; The molar ratio of the compound 4 to the chain extender in step (3) is (0.001-0.1):1; The molar ratio of the diisocyanate to the chain extender in step (3) is (2.0-3.0):1; The reaction of the polytetrahydrofuran, compound 4 and diisocyanate in step (3) is carried out under nitrogen protection; The reaction of the polytetrahydrofuran, compound 4 and diisocyanate in step (3) is carried out in the presence of a catalyst, wherein the catalyst is dibutyltin dilaurate; The reaction of the polytetrahydrofuran, compound 4 and diisocyanate in step (3) is carried out at room temperature; The reaction time of the polytetrahydrofuran, compound 4 and diisocyanate in step (3) is 12 to 36 hours; In step (3), the reaction of polytetrahydrofuran, compound 4 and diisocyanate is carried out in an organic solvent, and the organic solvent is selected from any one of tetrahydrofuran, dichloromethane and N,N-dimethylformamide.

5. The method for preparing toughened polyurethane based on dual non-covalent interactions according to claim 1, characterized in that: The temperature of the reaction after adding the chain extender in step (3) is 30 to 80 degrees Celsius; The chain extender added in step (3) is selected from any one of 1,4-butanediol, ethylene glycol, and triethylene glycol; The reaction time after adding the chain extender in step (3) is 12 to 36 hours.

6. The method for preparing toughened polyurethane based on dual non-covalent interactions according to claim 1, characterized in that: The molar ratio of the compound 4 in step (3) to the palladium acetate in step (4) is 1:(1.0-6.0); The reaction in step (4) is carried out at room temperature and the reaction time is 12 to 36 hours; The specific operation of the reaction in step (4) is: adding palladium acetate to a solution of polyurethane containing a tridentate pyridine ligand to react to obtain a palladium-coordinated polyurethane; The solvent of the solution is any one of dichloromethane, acetonitrile, tetrahydrofuran or N,N-dimethylformamide solution or a combination of at least two thereof.

7. The method for preparing toughened polyurethane based on dual non-covalent interactions according to claim 1, characterized in that: The molar ratio of the palladium-coordinated polyurethane in step (5) to compound 3 is 1:(0.1-3.0); The reaction temperature in step (5) is 20 to 40 degrees Celsius, and the reaction time is 8 to 20 hours.

8. The method for preparing toughened polyurethane based on dual non-covalent interactions according to claim 1, characterized in that: The molar ratio of the palladium-coordinated polyurethane with the crown ether structure in step (6) to the double-terminated secondary ammonium salt is 1:(1.0-2.0); The reaction temperature in step (6) is 20 to 40 degrees Celsius, and the reaction time is 12 to 36 hours. 9 . The toughened polyurethane based on dual non-covalent interactions prepared according to the method for preparing toughened polyurethane based on dual non-covalent interactions according to any one of claims 1 to 8 .

10. Use of the toughened polyurethane based on dual non-covalent interaction according to claim 9 in the synthesis of functional polymer materials.

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