Toughening type polyurethane based on dual non-covalent interaction as well as preparation method and application of toughening type polyurethane

Abstract

The invention provides toughened polyurethane based on dual non-covalent interaction as well as a preparation method and application thereof, and belongs to the technical field of supramolecular polymers, the preparation method comprises the following steps: preparing a monodentate pyridine ligand compound with a crown ether structure, and preparing polyurethane containing a tridentate pyridine ligand. Carrying out coordination reaction on the polyurethane containing the tridentate pyridine ligand and palladium acetate to obtain palladium coordinated polyurethane; the palladium-coordinated polyurethane reacts with a monodentate pyridine ligand compound with a crown ether structure to obtain the palladium-coordinated polyurethane with the crown ether structure, and then the palladium-coordinated polyurethane reacts with double-end-group secondary ammonium salt to obtain the toughening type polyurethane based on the dual non-covalent interaction. The toughened polyurethane disclosed by the invention simultaneously has two non-covalent interactions of subject-object recognition and metal coordination, so that the polyurethane can be toughened synergistically, and a polyurethane network is endowed with good dynamic property and mechanical property.

Description

Technical Field

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

[0002] Supramolecular polymers (SPs) are an emerging class of polymers. Unlike traditional covalent polymers (CPs), supramolecular polymers are composed of monomer units connected by non-covalent bonds. These non-covalent interactions include van der Waals forces, hydrogen bonds, Coulomb 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 stimulus responsiveness, adaptability, self-healing, etc., but this is accompanied by poor mechanical stability. Therefore, combining covalent polymers and supramolecular polymers through appropriate interactions is a promising strategy for producing high-performance elastomers.

[0003] Weaving is one of the oldest human skills. The highly ordered warp and weft threads work synergistically to give woven materials unique topological structures and rich mechanical behaviors. Inspired by this, researchers have tried to introduce woven topological structures into polymer science and developed a type of polymer material with a new topological structure - woven polymers. Woven polymers are a type of polymer network constructed with woven nodes as crosslinking points. Therefore, using weaving technology to achieve the synergy of covalent polymers and supramolecular polymers is crucial to improving the performance of traditional polymer materials.

[0004] Traditional polyurethane elastomers have the disadvantages of poor mechanical strength and insufficient toughness, which limits their application. Introducing non-covalent bonds into the polyurethane system can give polyurethane good toughness and dynamics. In this regard, supramolecular polymers are combined with traditional covalent polymers through weaving technology to construct toughened polyurethanes with the combined effects of metal coordination and host-guest recognition, providing a new idea for the design and construction of functional polymer materials. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is 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 preparation 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, and the reaction formula is as follows:

[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) The polyurethane containing a tridentate pyridine ligand is subjected to a coordination reaction with palladium acetate to obtain a palladium-coordinated polyurethane;

[0014] (5) The palladium-coordinated polyurethane obtained in step (4) reacts with Compound 3 to obtain a palladium-coordinated polyurethane with a crown ether structure;

[0015] (6) The palladium-coordinated polyurethane with a crown ether structure obtained in step (5) reacts with a bis-terminal secondary ammonium salt to obtain the toughened polyurethane based on dual non-covalent interactions.

[0016] The toughened polyurethane based on dual non-covalent interactions of the present invention has excellent mechanical properties and has inestimable application potential in the field of high-performance polymer materials. Among them, crown ether is introduced into the polyurethane system as a macrocyclic host, which can not only form a supramolecular network with secondary ammonium salt, endow the polyurethane with good dynamics and toughness, and increase the stability of the polyurethane. In the present invention, a supramolecular polymer is combined with a traditional covalent polymer through a weaving technique to construct a toughened polyurethane with the co-action of metal coordination and host-guest recognition, providing a new idea for the design and construction of functional polymer materials.

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

[0018] Preferably, the molar ratio of Compound 1 to Compound 2 in step (1) is (2.0 - 5.0):1, such as 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 a basic substance.

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

[0021] Preferably, the molar ratio of the compound 2 to the basic substance in step (1) is 1:(3.0 - 8.0), such as 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 more preferably N,N-dimethylformamide.

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

[0024] Preferably, the reaction time in step (1) is 15 to 30 hours, such as 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 carried out to obtain the monodentate pyridine ligand compound 3 with a crown ether structure.

[0026] The purification is carried out by separation and purification using silica gel column chromatography, and the eluent for silica gel column chromatography is a mixed solution of dichloromethane and methanol with a volume ratio of 15:1.

[0027] Preferably, the molar ratio of the 4-aminomethylbenzyl alcohol to the pyridine-2,6-dicarboxylic acid in step (2) is 1:(2.0 - 5.0), such as 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, such as 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 or a combination of at least two of dichloromethane, acetonitrile or N,N-dimethylformamide.

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

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

[0036] Preferably, the molar ratio of the polytetrahydrofuran to the chain extender in step (3) is (1.0 - 2.0):1, such as 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 compound 4 to the chain extender in step (3) is (0.001 - 0.1):1, such as 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, such as 2.0:1, 2.2:1, 2.5:1, 2.8:1 or 3:1.

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

[0040] Preferably, the reaction of the 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 the polytetrahydrofuran, compound 4 and diisocyanate in step (3) 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).

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

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

[0044] Preferably, the temperature of the reaction after adding the chain extender in step (3) is 30 to 80 °C, such as 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C or 80 °C, and more preferably 30 to 60 °C.

[0045] Preferably, the reaction time of the reaction after adding the chain extender in step (3) is 12 to 36 hours, such as 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 or a combination of at least two of 1,4-butanediol, ethylene glycol or triethylene glycol, 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), such as 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 the reaction in step (4) is 12 to 36 hours, such as 12 hours, 18 hours, 20 hours, 22 hours, 24 hours, 28 hours, 30 hours, 33 hours or 36 hours, and more preferably 24 to 36 hours.

[0051] Preferably, the specific operation of the reaction in step (4) is as follows: Palladium acetate is added to a dichloromethane, acetonitrile, or tetrahydrofuran solution of the polyurethane containing the tridentate pyridine ligand, and the reaction yields a 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), such as 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 temperature of the reaction in step (5) is 25 to 40 degrees Celsius, such as 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, such as 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 bis-terminal 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 temperature of the reaction in step (6) is 25 to 40 degrees Celsius, such as 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, such as 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 dual non-covalent interactions.

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

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

[0059] In the present invention, the host-guest recognition between the crown ether and the secondary ammonium salt forms a supramolecular polymer network. The woven knots formed by the metal coordination act as a connection between the covalent polymer and the supramolecular polymer, promoting the synergistic work of the two components and thus forming a strong and tough woven polymer network.

[0060] The dual non-covalent interactions of the present invention make the woven polymer network a highly dynamic network and endow 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 as described above.

[0062] On the other hand, the present invention provides the application of the toughened polyurethane based on dual non-covalent interactions as described above 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, toughened by dual non-covalent interactions. The dual non-covalent interactions are metal coordination and host-guest recognition. The presence of these two non-covalent interactions endows polyurethane with excellent mechanical properties and has significant application potential in the field of high-performance polymer materials.

[0066] When the addition amount of the woven knot in the polyurethane toughened by the dual non-covalent interactions provided by the present invention is 1 mol%, the Young's modulus is 27.5 MPa, the fracture strength is 15.8 MPa, the elongation at break is 1279%, and the toughness is 142 MJ / m 3 , while the Young's modulus of the polyurethane without introducing dual non-covalent interactions is only 14.6 MPa, the fracture strength is only 5.57 MPa, the elongation at break is only 628%, and the toughness is only 23.4 MJ / m 3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 is the 1 1H NMR spectrum of Compound 3.

[0068] Figure 2 is the 1 1H NMR spectrum of Compound 4.

[0069] Figure 3 is the GPC chart of WPN in the examples, where 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 vertex.

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

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

[0072] Figure 6 For the cyclic tensile test curves of CP-1, CP-3 and WPN in the examples. Detailed implementation manners

[0073] The technical solutions of the present invention will be further described below through specific implementation manners. Those skilled in the art should understand that the described examples are only to help understand the present invention and should not be regarded as specific limitations on 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 as shown below, and its synthesis method includes the following steps:

[0076]

[0077] Dissolve 1.7 g of Compound 1 and 0.49 g of Compound 2 in 80 mL of N,N-dimethylformamide, and add 0.9 g of potassium carbonate thereto. After stirring at 85 °C for 20 h, cool the reaction mixture to room temperature, filter to obtain a filtrate, concentrate under reduced pressure to obtain a crude product, and purify the crude product by flash column chromatography (eluent dichloromethane / methanol volume ratio = 15:1) to obtain Compound 3.

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

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

[0080]

[0081] Dissolve 1.8 g of 4-aminomethylbenzyl alcohol, 3.5 g of EDC·HCl and 1.5 g of DMAP in 70 mL of dichloromethane, and add 1 g of pyridine-2,6-dicarboxylic acid thereto. Stir the mixture overnight at room temperature and purify by column chromatography (eluent dichloromethane / methanol volume ratio = 20:1) to obtain Compound 4.

[0082] The 1H NMR spectrum of Compound 4 is as Figure 2 shown.

[0083] The epoxy resin is epoxy resin E51;

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

[0085] Example 1

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

[0087] Add 6 g of polytetrahydrofuran, 17 mg of compound 4, 1.41 g of hexamethylene diisocyanate, and 10 mg of dibutyltin dilaurate in a 5 mL tetrahydrofuran solution. React at room temperature for 12 h under nitrogen protection. Then add 0.3 g of 1,4-butanediol and continue to react at 50 °C for 15 h. Add 10 mg of palladium acetate and react at 25 °C for 12 h. Then add 45.7 mg of compound 3 and stir at 25 °C for 12 h. Next, add 30 mg of the dual-terminal secondary ammonium salt and stir at 25 °C for 12 h. End the reaction and evaporate the solvent to obtain a toughened polyurethane WPN based on dual non-covalent interactions.

[0088] Example 2

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

[0090] Add 5 g of polytetrahydrofuran, 17 mg of compound 4, 1.41 g of hexamethylene diisocyanate, and 10 mg of dibutyltin dilaurate in a 5 mL tetrahydrofuran solution. React at room temperature for 24 h under nitrogen protection. Then add 0.3 g of 1,4-butanediol and continue to react at 60 °C for 24 h. Add 10 mg of palladium acetate and react at 25 °C for 30 h. Then add 45.7 mg of compound 3 and stir at 25 °C for 8 h. Next, add 60 mg of the dual-terminal secondary ammonium salt and stir at 25 °C for 24 h. End the reaction and evaporate the solvent to obtain a toughened polyurethane WPN based on dual non-covalent interactions.

[0091] Example 3

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

[0093] Add 9 g of polytetrahydrofuran, 34 mg of compound 4, 1.1 g of hexamethylene diisocyanate, and 10 mg of dibutyltin dilaurate in a 10 mL tetrahydrofuran solution. React at room temperature for 12 h under nitrogen protection. Then add 0.3 g of 1,4-butanediol and continue to react at 80 °C for 12 h. Add 20 mg of palladium acetate and react at 25 °C for 36 h. Then add 91.2 mg of compound 3 and stir at 30 °C for 18 h. Next, add 60 mg of the dual-terminal secondary ammonium salt and stir at 40 °C for 12 h. End the reaction and evaporate the solvent to obtain a toughened polyurethane WPN based on dual non-covalent interactions.

[0094] Example 4

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

[0096] Add an 8 g polytetrahydrofuran, 34 mg of compound 4, 1.43 g of hexamethylene diisocyanate, and 10 mg of dibutyltin dilaurate in a 10 mL tetrahydrofuran solution. React at room temperature for 3 h under nitrogen protection, then add 0.3 g of 1,4-butanediol thereto, continue to react at 80 °C for 12 h, add 20 mg of palladium acetate thereto, react at 25 °C for 36 h, then add 91.2 mg of compound 3, stir at 40 °C for 12 h, then add 120 mg of a dual-terminal secondary ammonium salt thereto, stir at 40 °C for 24 h, end the reaction, and evaporate the solvent to obtain a toughened polyurethane WPN based on dual non-covalent interactions.

[0097] Example 5

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

[0099] Add a 12 g polytetrahydrofuran, 105 mg of compound 4, 1.45 g of hexamethylene diisocyanate, and 10 mg of dibutyltin dilaurate in a 10 mL tetrahydrofuran solution. React at room temperature for 3 h under nitrogen protection, then add 0.3 g of 1,4-butanediol thereto, continue to react at 30 °C for 36 h, add 60 mg of palladium acetate thereto, react at 25 °C for 12 h, then add 281 mg of compound 3, stir at 25 °C for 18 h, then add 190 mg of a dual-terminal secondary ammonium salt thereto, stir at 25 °C for 12 h, end the reaction, and evaporate the solvent to obtain a toughened polyurethane WPN based on dual non-covalent interactions.

[0100] Example 6

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

[0102] Under nitrogen protection, a 10 mL tetrahydrofuran solution containing 10 g of polytetrahydrofuran, 105 mg of Compound 4, 1.45 g of hexamethylene diisocyanate, and 10 mg of dibutyltin dilaurate was reacted at room temperature for 3 h. Then, 0.3 g of 1,4-butanediol was added thereto, and the reaction was continued at 50 °C for 24 h. Then, 60 mg of palladium acetate was added thereto, and the reaction was carried out at 25 °C for 12 h. Then, 281 mg of Compound 3 was added, and the mixture was stirred at 35 °C for 12 h. Then, 380 mg of a double-ended 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 example provides a toughened polyurethane based on dual non-covalent interactions, and its preparation method comprises the following steps:

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

[0106] Comparative Example 2

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

[0108] Under nitrogen protection, a 10 mL tetrahydrofuran solution containing 9 g of polytetrahydrofuran, 34 mg of Compound 4, 1.1 g of hexamethylene diisocyanate, and 10 mg of dibutyltin dilaurate was reacted at room temperature for 12 h. Then, 0.3 g of 1,4-butanediol was added thereto, and the reaction was continued at 80 °C for 12 h. Then, 20 mg of palladium acetate was added thereto, and the reaction was carried out at 25 °C for 36 h. Then, 91.2 mg of Compound 3 was added, and the mixture was 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 It is the GPC spectrogram of the WPN prepared in Example 4. Figure 3 It can be seen that the number-average molecular weight of WPN is 54 kDa.

[0110] Figure 4 It is the thermogravimetric curve of the WPN prepared in Example 4. The 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 tensile rate of 100 mm / min. As Figure 5 shown, both the fracture strength and toughness of CP-3 are better than those of CP-1, indicating that the metal coordination plays an important role in the polymer. Moreover, the fracture strength and toughness of WPN are the best among the three, indicating that the combined action of two non-covalent interactions, metal coordination and host-guest recognition, realizes the improvement of the 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. As Figure 6 shown, the area of the hysteresis loop of WPN is much larger than that of CP-1 and CP-3, indicating that the synergistic action of metal coordination and host-guest recognition endows the polyurethane with good energy dissipation ability.

[0113] The applicant declares that the present invention uses the above examples to illustrate the polyurethane of the present invention, its preparation method and application, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent substitution of the raw materials selected for the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A preparation method of a toughened polyurethane based on dual non-covalent interactions, characterized in that, The preparation method includes the following steps: (1) Compound 1 and Compound 2 react to obtain a monodentate pyridine ligand Compound 3 with a crown ether structure, and the reaction formula is as follows: ； (2) 4-(Aminomethyl)benzyl alcohol reacts with pyridine-2,6-dicarboxylic acid to obtain Compound 4, and the reaction formula is as follows: ； (3) Poly(tetrahydrofuran), Compound 4 and a diisocyanate react, and then a chain extender is added to obtain a polyurethane containing a tridentate pyridine ligand; (4) The polyurethane containing the tridentate pyridine ligand is subjected to a coordination reaction with palladium acetate to obtain a palladium-coordinated polyurethane; (5) The palladium-coordinated polyurethane obtained in step (4) reacts with Compound 3 to obtain a palladium-coordinated polyurethane with a crown ether structure; (6) The palladium-coordinated polyurethane with a crown ether structure obtained in step (5) reacts with a bis-terminal secondary ammonium salt to obtain the toughened polyurethane based on dual non-covalent interactions.

2. The preparation method of the toughened polyurethane based on dual non-covalent interactions according to claim 1, wherein, In step (1), the molar ratio of Compound 1 to Compound 2 is (2.0 - 5.0):1; In step (1), the reaction is carried out in the presence of a basic substance; the basic substance is selected from any one of potassium carbonate, cesium carbonate or potassium bicarbonate; In step (1), the molar ratio of Compound 2 to the basic substance is 1:(3.0 - 8.0); In step (1), the reaction 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; In step (1), the reaction is carried out under reflux conditions, and the reaction time is 15 to 30 hours.

3. The preparation method of the toughened polyurethane based on dual non-covalent interactions according to claim 1, characterized in that, In step (2), the molar ratio of 4-(aminomethyl)benzyl alcohol to pyridine-2,6-dicarboxylic acid is 1:(2.0 - 5.0); In step (2), the reaction is carried out in the presence of an activator, and the activator is selected from 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride; In step (2), the reaction is carried out in the presence of a catalyst, and the catalyst is selected from 4-dimethylaminopyridine; In step (2), the reaction is carried out at room temperature; the reaction time is 12 to 24 hours; In step (2), the reaction is carried out in a solvent, and the solvent is selected from any one of dichloromethane, acetonitrile, N,N-dimethylformamide.

4. The preparation method of the toughened polyurethane based on dual non-covalent interactions according to claim 1, wherein, In step (3), the number-average molecular weight of the poly(tetrahydrofuran) is 500 to 3000; In step (3), the diisocyanate includes any one or a combination of at least two of isophorone diisocyanate, hexamethylene diisocyanate or toluene diisocyanate; In step (3), the molar ratio of the poly(tetrahydrofuran) to the chain extender is (1.0 - 2.0):1; In step (3), the molar ratio of Compound 4 to the chain extender is (0.001 - 0.1):1; In step (3), the molar ratio of the diisocyanate to the chain extender is (2.0 - 3.0):1; In step (3), the reaction of the poly(tetrahydrofuran), Compound 4 and the diisocyanate is carried out under nitrogen protection; In step (3), the reaction of the poly(tetrahydrofuran), Compound 4 and the diisocyanate is carried out in the presence of a catalyst, and the catalyst is dibutyltin dilaurate; In step (3), the reaction of the poly(tetrahydrofuran), Compound 4 and the diisocyanate is carried out at room temperature; The reaction time of the polytetrahydrofuran, compound 4 and the diisocyanate described in step (3) is 12 to 36 hours; The reaction of the polytetrahydrofuran, compound 4 and the diisocyanate described in step (3) 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 preparation method of the 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 described in step (3) is 30 to 80 °C; The chain extender added in step (3) is selected from any one of 1,4-butanediol, ethylene glycol, and triethylene glycol; The reaction time of the reaction after adding the chain extender described in step (3) is 12 to 36 hours.

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

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

8. The preparation method of the toughened polyurethane based on dual non-covalent interactions according to claim 1, characterized in that, The molar ratio of the palladium-coordinated polyurethane with a crown ether structure to the bis-terminal secondary ammonium salt described in step (6) is 1:(1.0 - 2.0); The temperature of the reaction described in step (6) is 20 to 40 °C, and the reaction time is 12 to 36 hours.

9. A toughened polyurethane based on dual non-covalent interactions prepared by the preparation method of the toughened polyurethane based on dual non-covalent interactions according to any one of claims 1 - 8.

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

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