A polyurethane epoxy polymer network and its preparation method and application

Abstract

The present invention provides a polyurethane epoxy polymer network and its preparation method and application. The present invention belongs to the technical field of braided polymer networks. The preparation method comprises: (1) reacting a polyol, a small molecule chain extender, a diisocyanate and a tridentate ligand to obtain a polyurethane; (2) dissolving the obtained polyurethane in an organic solvent, adding a divalent palladium compound and a monodentate ligand to carry out a coordination reaction; (3) adding an epoxy resin and a curing agent to the reaction solution obtained in step (2), removing the solvent after mixing, and curing to obtain a polyurethane epoxy polymer network. In the present invention, linear polyurethane and epoxy resin are interpenetrated through palladium-coordinated braided nodes, and the braided network is used to enhance the mechanical properties and energy absorption capacity of the polyurethane and epoxy resin, reduce the phase separation tendency between the two polymers, enable the material to withstand higher stress levels, improve its toughness, and improve its maximum elongation and plastic deformation capacity while maintaining the original strength of the polymer.

Description

Technical Field

[0001] The present invention belongs to the technical field of braided polymer networks (WPNs), and in particular relates to a polyurethane epoxy polymer network and a preparation method and application thereof. Background Art

[0002] With the development of science and technology, the demand for high-performance, multifunctional materials is growing. Interpolymer networks (IPNs), as a new type of composite material, can combine the advantages of different polymers to meet the needs of specific application fields such as aerospace, automotive, electronics, and biomedicine.

[0003] Covalent polymer networks (CPNs) are cross-linked through covalent bonds, giving the materials excellent mechanical strength and chemical stability. However, these high-strength cross-links also limit the material's dynamic responsiveness. In contrast, supramolecular polymer networks (SPNs) achieve cross-linking through non-covalent interactions, exhibiting good adaptability and flexibility, but their weaker cross-links result in lower mechanical strength.

[0004] Braided polymer networks (WPNs) combine the strength of covalent polymers with the reproducibility of supramolecular polymer networks. Metal complexes, with their well-defined directionality and predictable cross-linking geometry, are often used to construct molecular knots. Although scientists have recently utilized metal coordination to prepare a variety of molecular knots and organic frameworks, their practical application in adhesives remains limited. Leigh's team (Danon, Jonathan J, et al. "Braiding a molecular knot with eight crossings." Science 355.6321(2017):159-162.) expanded the Star of David molecular knot by adjusting the molecular linking groups and incorporating a chloride ion template, resulting in a novel, non-interlaced, up-and-down structure for the tetramer's molecular interweaving. They successfully constructed a molecular knot with eight crossings.

[0005] Guangfeng Li et al. (G. Li, J. Zhao, Z. Zhang, et al., Angew. Chem. Int. Ed. 2022, 61, e202210078; Angew. Chem. 2022, 134, e202210078.) fabricated polyurethane and polysiloxane braided polymer networks (WPNs) using copper atoms for coordination. These networks exhibit mechanical strength exceeding that of covalent and supramolecular polymer networks and exhibit excellent self-healing properties. The braided conformation induces entanglement of polymer chains. Under stress, the metal coordination dissociates, accompanied by limited slip between the two polymer chains. Due to the entanglement, the WPN network remains intact. Compared to the complete destruction of the supramolecular cross-linked network structure, the dual interactions within the braided cross-links—metal coordination and entanglement—ensure the WPN's superior strength.

[0006] Epoxy resin is a thermosetting resin with excellent adhesion, chemical resistance, electrical insulation, mechanical strength, and heat resistance. It is widely used in coatings, adhesives, composite materials, electronic packaging, civil engineering, and other fields. Although epoxy resin has many excellent properties due to its unique chemical structure, its inherent brittleness and low impact resistance have limited its application in certain fields.

[0007] Polyurethane is a polymer material with excellent physical properties, chemical stability, and biocompatibility. It is widely used in coatings, adhesives, elastomers, foam plastics, fibers, synthetic leather, and other fields. However, its relatively poor weather resistance and mechanical strength limit its application in high-end fields.

[0008] Epoxy resin and polyurethane each have their own advantages, but they have poor compatibility and it is difficult to form a uniform and stable polymer through direct blending for use as an elastomer or adhesive.

[0009] Therefore, chemical modification of epoxy and polyurethane has been a hot topic of research. However, developing elastomers or adhesives with both mechanical properties and ductility remains a major challenge. Summary of the Invention

[0010] In response to the shortcomings of the prior art, the present invention provides a polyurethane-epoxy polymer network, a preparation method, and applications thereof. The polyurethane-epoxy polymer network of the present invention has a woven polymer network structure with a unique topological structure and dynamic properties of dispersing stress and dissipating energy under external stimuli, thus enabling its use as a high-performance material.

[0011] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0012] In one aspect, the present invention provides a method for preparing a polyurethane epoxy polymer network, the method comprising the following steps:

[0013] (1) Polyurethane is obtained by reacting polyol, small molecule chain extender, diisocyanate and tridentate ligand;

[0014] (2) dissolving the polyurethane obtained in step (1) in an organic solvent, adding a divalent palladium compound and a monodentate ligand, and performing a coordination reaction;

[0015] (3) Adding epoxy resin and curing agent to the reaction solution obtained in step (2), removing the solvent after mixing, and then curing to obtain the polyurethane epoxy polymer network.

[0016] In the present invention, polyurethane is obtained by reacting polyol, small molecule chain extender, diisocyanate and tridentate ligand, then coordinated with divalent palladium compound and monodentate ligand, and finally reacted with epoxy resin and curing agent and cured to obtain a woven polymer network with high strength and dynamic properties. The strength and dynamic properties of the woven polymer network are derived from the effects of molecular entanglement and metal coordination, respectively, so that the polymer as a whole can withstand greater stress and have higher toughness.

[0017] The braided polymer network obtained by the present invention has a unique topological structure and dynamic characteristics of dispersing stress and dissipating energy under external stimulation, and can be used as a high-performance material. The dual effects of entanglement and coordination in the braided network of the present invention ensure both the dynamics of the network and the strength of the network. Specifically, the braided polymer network contains a plurality of metal-coordinated braided nodes. Under the action of external force, the metal coordination dissociates, accompanied by limited slip between the two polymer chains, so that the stress can be dispersed throughout the network; and the presence of entanglement ensures the integrity of the network structure, so the overall strength is high and has good recovery. Therefore, the polymer network of the present invention is an ideal material as an elastomer or adhesive.

[0018] Preferably, the polyol is selected from polyols terminated with hydroxyl groups at both ends.

[0019] Preferably, the polyol is selected from polytetrahydrofuran, polyethylene glycol or polypropylene glycol.

[0020] Preferably, the small molecule chain extender is a small molecule diol.

[0021] Preferably, the small molecule diol includes any one of 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or 4-phenylenediol, or a combination of at least two thereof.

[0022] Preferably, the diisocyanate is selected from any one or a combination of at least two of hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI) or dicyclohexylmethane diisocyanate (HMDI).

[0023] Preferably, the tridentate ligand is the following compound:

[0024] .

[0025] Preferably, the mass ratio of the polyol to the small molecule chain extender in step (1) is (30-80): (1-5), for example, 30:1, 30:2, 30:3, 30:4, 30:5, 35:1, 35:2, 35:3, 35:4, 35:5, 38:1, 38:2, 38:3, 38:4, 38:5, 40:1, 40:2, 40:3, 40:5, 45:1, 45:2, 45:3, 45:4 , 45:5, 50:1, 50:2, 50:3, 50:4, 55:1, 55:2, 55:3, 55:4, 55:5, 60:1, 60:3, 60:5, 68:1, 68:2, 68:3, 68:4, 68:5, 70:1, 70:2, 70:3, 70:4, 70:5, 75:1, 75:2, 75:3, 75:4, 75:5, 80:1, 80:3, 80:5, etc.

[0026] Preferably, the mass ratio of the polyol to diisocyanate in step (1) is (30-80): (3-15), for example, 30:1, 30:2, 30:3, 30:4, 30:5, 30:6, 30:7, 30:8, 30:9, 30:10, 30:11, 30:12, 30:13, 30:14, 30:15, 35:1, 35:2, 35:3, 35:4, 35:5, 35:6, 35:8, 35:10, 35:11, 35:13 、35:15、38:1、38:2、38:3、38:4、38:5、38:6、38:8、38:10、38:11、38:13、38:15、40:1、40:2、40:3、40:5、40:6、40:8、40:10、40:11、40:13、40:15、45:1、45:2、45:3、45:4、45:5、45:6、45:8、45:10、45:11、45:13、45:1 5, 50:1, 50:2, 50:3, 50:4, 50:6, 50:8, 50:10, 50:11, 50:13, 50:15, 55:1, 55:2, 55:3, 55:4, 55:5, 55:8, 55:10, 55:11, 55:13, 55:15, 60:1, 60:3, 60:5, 60:8, 60:10, 60:11, 60:13, 60:15, 68:1, 68:2, 68:3, 68:4, 68: 5, 68:6, 68:8, 68:10, 68:11, 68:13, 68:15, 70:1, 70:2, 70:3, 70:4, 70:5, 70:8, 70:11, 70:13, 70:15, 75:1, 75:2, 75:3, 75:4, 75:5, 75:8, 75:10, 75:11, 75:13, 75:15, 80:1, 80:3, 80:5, 80:7, 80:11, 80:13, 80:15, etc.

[0027] Preferably, the mass ratio of the polyol to the tridentate ligand in step (1) is (30-80): (0.4-2), for example, 30:0.4, 30:0.6, 30:0.8, 30:1, 30:1.3, 30:1.5, 30:1.8, 30:2, 35:0.4, 35:0.5, 35:0.8, 35:1, 35:1.5, 35:2, 38:0.4, 38:0.5, 38:0.8, 38:1, 38:1.5, 38:1.8, 38:2, 40:0.4, 40:0.8, 40:1, 40:1.3, 40:2, 45:0.4, 45:0.8, 45:1 , 45:1.3, 45:1.5, 45:2, 50:0.4, 50:0.8, 50:1, 50:1.5, 50:2, 55:0.4, 55:1, 55:1.3, 55:1.5, 55:2, 60:0.5, 60:0.8, 60:1, 60:1.5, 60:2, 68:0.5, 68:0.8, 68:1, 68:1.5, 68:2, 70:0.5, 70:0.8, 70:1, 70:1.5, 70:1.8, 75:0.7, 75:0.9, 75:1, 75:1.8, 75:2, 80:0.4, 80:1, 80:1, etc.

[0028] Preferably, the reaction in step (1) is carried out in the presence of a catalyst.

[0029] Preferably, the catalyst is dibutyltin dilaurate.

[0030] Preferably, the mass ratio of the catalyst to the polyol is 1:(15-40), for example, 1:15, 1:18, 1:20, 1:23, 1:25, 1:28, 1:30, 1:33, 1:35, 1:38 or 1:40, etc.

[0031] Preferably, the reaction in step (1) is carried out in an organic solvent.

[0032] Preferably, the organic solvent is selected from any one of tetrahydrofuran, N,N-dimethylformamide or 1,4-dioxane, or a combination of at least two thereof.

[0033] Preferably, the mass ratio of the organic solvent to the polyol is (500-2000): (30-80), for example, 500:30, 500:35, 500:40, 500:50, 500:60, 500:70, 500:80, 700:30, 700:35, 700:40, 700:50, 700:60, 700:70, 700:80, 1000:30, 1000:35, 1000:40, 1000:50, 1000:60, 10 00:70, 1000:80, 1300:30, 1300:35, 500:40, 1300:50, 1300:60, 1300:70, 1300:80, 1500:30, 1500:35, 1500:40, 1500:50, 1500:60, 1500:70, 1500:80, 2000:30, 2000:35, 2000:40, 2000:50, 2000:60, 2000:70, 2000:80, etc.

[0034] Preferably, the reaction temperature in step (1) is 40-60°C (e.g., 40°C, 45°C, 50°C, 55°C, 60°C, etc.), preferably 50°C, and the reaction time is 3-12 h, e.g., 3 h, 5 h, 7 h, 9 h, 10 h, 11 h or 12 h.

[0035] Preferably, after the reaction in step (1) is completed, the solvent is removed by distillation under reduced pressure to obtain polyurethane.

[0036] Preferably, the reduced pressure distillation temperature is 30-50°C (e.g., 30°C, 33°C, 35°C, 40°C, 45°C or 50°C), the vacuum degree is -0.090~-0.095Mpa (e.g., -0.090Mpa, -0.092Mpa, -0.095Mpa, etc.), and the reduced pressure distillation time is 0.5~2h (e.g., 0.5h, 1h, 2h, etc.).

[0037] Preferably, the divalent palladium compound in step (2) is selected from palladium acetate or palladium tetrafluoroborate.

[0038] Preferably, the monodentate ligand in step (2) is selected from the following compounds:

[0039] .

[0040] Preferably, the mass ratio of the polyurethane to the divalent palladium compound in step (2) is (250-400):1, for example, 250:1, 255:1, 260:1, 270:1, 280:1, 300:1, 330:1, 350:1, 380:1 or 400:1.

[0041] Preferably, the mass ratio of the polyurethane to the monodentate ligand in step (2) is (250-400):(1-9), for example, 250:1, 250:3, 250:5, 250:7, 250:9, 280:1, 280:3, 280:5, 280:7, 300:9, 300:1, 300:3, 300:5, 300:7, 300:9, 350:1, 350:3, 350:5, 350:7, 350:9, 380:1, 380:3, 380:5, 380:7, 380:9, 400:1, 400:3, 400:5, 400:7, 400:9, etc.

[0042] Preferably, the organic solvent in step (2) is selected from any one or a combination of at least two of dichloromethane, N,N-dimethylformamide or acetonitrile.

[0043] Preferably, the mass ratio of the polyurethane to the organic solvent in step (2) is (250-400): (8000-10000), for example, 250:8000, 280:8000, 300:8000, 330:8000, 350:8000, 380:8000, 400:8000, 250:8500, 280:8500, 300:8500, 330:8500, 350:8500, 380:8500, 400:8500, 250:9000, 280:9000, 280:9000, 25 ... 0:9000, 300:9000, 330:9000, 350:9000, 380:9000, 400:9000, 250:9500, 280:9500, 300:9500, 330:9500, 350:9500, 380:9500, 400:9500, 250:10000, 280:10000, 300:10000, 330:10000, 350:10000, 380:10000, 400:10000, etc.

[0044] Preferably, the temperature of the coordination reaction in step (2) is 20-30°C, such as 20°C, 25°C, 30°C, etc., and the time of the coordination reaction is 2-8h, such as 2h, 3h, 4h, 5h, 6h, 7h or 8h.

[0045] Preferably, the epoxy resin monomer in step (3) is a bisphenol A epoxy resin monomer.

[0046] Preferably, the bisphenol A epoxy resin monomer is selected from E51, E44, E55, etc.

[0047] Preferably, the curing agent in step (3) is selected from di-secondary amine compounds.

[0048] Preferably, the di-secondary amino compound is selected from any one of dimethylethylenediamine, N,N'-diethylethylenediamine, and N,N'-diisopropylethylenediamine, or a combination of at least two thereof.

[0049] Preferably, the mass ratio of the epoxy resin monomer in step (3) to the polyurethane in step (2) is (1-15):7, for example, 1:7, 2:7, 2.5:7, 3:7, 3.5:7, 4:7, 5:7, 6:7, 7:7, 8:7, 9:7, 10:7, 11:7, 12:7, 13:7, 14:7 or 15:7, etc.

[0050] Preferably, the mass ratio of the curing agent in step (3) to the polyurethane in step (2) is (0.2-3):7, for example, 0.2:7, 0.4:7, 0.6:7, 0.8:7, 1:7, 1.5:7, 1.8:7, 2:7, 2.3:7, 2.5:7, 2.8:7 or 3:7, etc.

[0051] Preferably, the solvent is removed in step (3) by distillation under reduced pressure.

[0052] Preferably, the reduced pressure distillation temperature is 30-50°C (e.g., 30°C, 33°C, 35°C, 40°C, 45°C or 50°C), the vacuum degree is -0.080~-0.090Mpa (e.g., -0.080Mpa, -0.085Mpa, -0.090Mpa, etc.), and the reduced pressure distillation time is 0.5~2h (e.g., 0.5h, 0.8h, 1h, 1.5h, 1.8h, 2h, etc.).

[0053] Preferably, the curing temperature in step (3) is 60-100°C (for example, 60°C, 70°C, 80°C, 90°C or 100°C), and the curing time is 3-12h (for example, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h).

[0054] In the present invention, the polyurethane epoxy polymer network prepared by the above method is interwoven with the polyurethane and epoxy resin networks by using braided nodes, and the braided nodes formed have the following structure:

[0055] .

[0056] The present invention interpenetrates linear polyurethane and epoxy resin through palladium-coordinated braided nodes, utilizing the braided network to enhance the mechanical properties and energy absorption capacity of the polyurethane and epoxy resin, thereby enabling the material to withstand higher stress levels, improving its toughness, and enhancing its maximum stretchability and plastic deformation capacity while maintaining the original strength of the polymer.

[0057] In another aspect, the present invention provides a polyurethane epoxy polymer network prepared by the preparation method described above.

[0058] In another aspect, the present invention provides use of the polyurethane epoxy polymer network described above in an elastomeric material or an adhesive.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] The present invention interpenetrates linear polyurethane and epoxy resin through palladium-coordinated braiding nodes to create a warp-and-weft braided polyurethane-modified epoxy polymer network. This braided network enhances the mechanical properties and energy absorption capacity of the polyurethane and epoxy resin, allowing the material to withstand higher stress levels and improve its toughness. While maintaining the polymer's original strength, it also increases its maximum stretchability and plastic deformation capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 These are infrared absorption spectra (FTIR) of the WPN polyurethane epoxy polymer network (WPU-EP) prepared in Example 2, the SPN polyurethane epoxy polymer network (SPU-EP) prepared in Comparative Example 1, and the CPN polyurethane epoxy polymer network (CPU-EP) prepared in Example 3.

[0062] Figure 2 The H NMR of the monodentate ligand ( 1 H NMR) spectrum.

[0063] Figure 3 The H NMR of the tridentate ligand ( 1 H NMR) spectrum.

[0064] Figure 4 These are stress-strain curves of the WPN polyurethane epoxy polymer network (WPU-EP) prepared in Example 2, the SPN polyurethane epoxy polymer network (SPU-EP) prepared in Comparative Example 1, the CPN polyurethane epoxy polymer network (CPU-EP) prepared in Comparative Example 2, and the linear polyurethane epoxy resin blend network (PU / EP blend) prepared in Comparative Example 3. DETAILED DESCRIPTION

[0065] 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 merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0066] The raw materials involved in the following examples and comparative examples are as follows:

[0067] The structure of the tridentate ligand is , its synthesis method comprises the following steps:

[0068] 500 mg of 2,6-pyridinedicarboxylic acid and 2.92 g of 4-dimethylaminopyridine were dissolved in 80 mL of dichloromethane. The resulting solution was cooled to 0°C, and 2.87 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1.64 g of p-(aminomethyl)benzyl alcohol were added. The mixture was stirred overnight, and the volatiles were removed. The resulting organic phase was washed with deionized water and extracted with dichloromethane. The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation. The residue was purified by silica gel column chromatography using a mixture of petroleum ether and ethyl acetate (2:3 by volume) as the eluent to obtain the tridentate ligand product.

[0069] The H NMR spectrum of the tridentate ligand is as follows Figure 3 shown.

[0070] The structure of the monodentate ligand is , its synthesis method comprises the following steps:

[0071] 1) Dissolve 580 mg of 2,6-bis(bromomethyl)pyridine, 1.3 g of 4-{[N-(Boc)methylamino]methyl}phenol, and 910 mg of potassium carbonate in 40 mL of THF. Stir the solution at 100°C overnight, then remove volatiles. The resulting solid is then dissolved in dichloromethane and washed with deionized water. The organic phase is dried over anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation. The residue is purified by silica gel column chromatography using a dichloromethane / methanol (19 / 1, by volume) mixture as the eluent to obtain the intermediate as a light yellow powder.

[0072] 2) To a solution of 200 mg of the intermediate product in dichloromethane, add 2 mL of trifluoroacetic acid dropwise. After stirring at room temperature for 2 hours, wash the solution with 2.0 M sodium bicarbonate solution and extract with dichloromethane. The combined organic phases are dried over anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation to yield the monodentate ligand product.

[0073] The H NMR spectrum of the monodentate ligand is as follows Figure 2 shown.

[0074] The epoxy resin was epoxy resin E51, purchased from Shandong Yousuo Chemical Technology Co., Ltd.

[0075] Polytetrahydrofuran was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0076] Example 1

[0077] This embodiment provides a polyurethane epoxy polymer network, the preparation method of which includes the following steps:

[0078] 0.72g of polytetrahydrofuran, 0.01g of 1,4-butanediol, 0.03g of HDI, and 0.004g of a tridentate ligand were mixed in 10ml of tetrahydrofuran solvent. 0.02g of dibutyltin dilaurate was added and the mixture was reacted at 50°C for 3h. After the reaction, the mixture was distilled under reduced pressure at -0.090 MPa for 1h to remove the solvent. The mixture was then dissolved in 15ml of dichloromethane, and 0.0023g of palladium acetate and 0.0037g of a monodentate ligand were added. The mixture was reacted at 25°C for 6h to produce a polyurethane. 0.14g of epoxy resin E51 and 0.034g of dimethylethylenediamine were then added to the polyurethane solution. The mixture was stirred thoroughly and then distilled under reduced pressure at -0.090 MPa for 1h to remove the solvent. The mixture was cured at 80°C for 12h to produce a polyurethane epoxy polymer network.

[0079] Example 2

[0080] This embodiment provides a polyurethane epoxy polymer network, the preparation method of which includes the following steps:

[0081] 0.69g of polytetrahydrofuran, 0.05g of 1,4-butanediol, 0.12g of HDI, and 0.02g of a tridentate ligand were mixed in 10ml of tetrahydrofuran solvent. 0.02g of dibutyltin dilaurate was added and the mixture was reacted at 50°C for 3h. After the reaction, the solvent was removed by vacuum distillation at -0.095 MPa for 1h. The mixture was then dissolved in 15ml of dichloromethane, and 0.011g of palladium acetate and 0.019g of a monodentate ligand were added. The mixture was reacted at 25°C for 6h to produce a polyurethane. 0.14g of epoxy resin E51 and 0.034g of dimethylethylenediamine were then added to the polyurethane solution. The mixture was stirred thoroughly and then the solvent was removed by vacuum distillation at -0.090 MPa for 1h. The mixture was cured at 80°C for 12h to produce a polyurethane epoxy polymer network.

[0082] Example 3

[0083] This embodiment provides a polyurethane epoxy polymer network, the preparation method of which includes the following steps:

[0084] 0.34g of polytetrahydrofuran, 0.05g of 1,4-butanediol, 0.12g of HDI, and 0.02g of a tridentate ligand were mixed in 10ml of tetrahydrofuran solvent. 0.02g of dibutyltin dilaurate was added and the mixture was reacted at 50°C for 3h. After the reaction, the solvent was removed by vacuum distillation at -0.090 MPa for 2h. The mixture was then dissolved in 15ml of dichloromethane, and 0.011g of palladium acetate and 0.019g of a monodentate ligand were added. The mixture was reacted at 25°C for 6h to produce a polyurethane. 0.14g of epoxy resin E51 and 0.034g of dimethylethylenediamine were then added to the polyurethane solution. The mixture was stirred thoroughly and then the solvent was removed by vacuum distillation at -0.080 MPa for 2h. The mixture was cured at 80°C for 12h to produce a polyurethane epoxy polymer network.

[0085] Example 4

[0086] This embodiment provides a polyurethane epoxy polymer network, the preparation method of which includes the following steps:

[0087] 0.69g of polytetrahydrofuran, 0.05g of 1,4-butanediol, 0.12g of HDI, and 0.02g of a tridentate ligand were mixed in 10ml of tetrahydrofuran solvent. 0.02g of dibutyltin dilaurate was added and the mixture was reacted at 50°C for 3h. After the reaction, the solvent was removed by vacuum distillation at -0.090 MPa for 0.5h. The mixture was then dissolved in 15ml of dichloromethane, 0.011g of palladium acetate and 0.019g of a monodentate ligand were added, and the mixture was reacted at 25°C for 6h to produce a polyurethane. 0.20g of epoxy resin E51 and 0.05g of dimethylethylenediamine were then added to the polyurethane solution. The mixture was stirred thoroughly and the solvent was removed by vacuum distillation at -0.090 MPa for 0.5h. The mixture was cured at 80°C for 12h to produce a polyurethane epoxy polymer network.

[0088] Example 5

[0089] This embodiment provides a polyurethane epoxy polymer network, the preparation method of which includes the following steps:

[0090] 0.69g of polytetrahydrofuran, 0.05g of 1,4-butanediol, 0.12g of HDI, and 0.02g of a tridentate ligand were mixed in 10ml of tetrahydrofuran solvent. 0.02g of dibutyltin dilaurate was added and the mixture was reacted at 50°C for 3h. After the reaction, the solvent was removed by vacuum distillation at -0.095 MPa for 0.5h. The mixture was then dissolved in 15ml of dichloromethane, and 0.011g of palladium acetate and 0.019g of a monodentate ligand were added. The mixture was reacted at 25°C for 6h to produce a polyurethane. 0.35g of epoxy resin E51 and 0.079g of dimethylethylenediamine were then added to the polyurethane solution. The mixture was stirred thoroughly and the solvent was removed by vacuum distillation at -0.090 MPa for 0.5h. The mixture was cured at 80°C for 12h to produce a polyurethane epoxy polymer network.

[0091] Comparative Example 1

[0092] This comparative example provides a polyurethane epoxy polymer network, the preparation method of which comprises the following steps:

[0093] 0.15 g of monodentate ligand, 0.14 g of epoxy resin E51, and 0.034 g of N,N-dimethyl-1,2-ethylenediamine were dissolved in 15 ml of dichloromethane and reacted at 80°C for 12 h. After the reaction, the solvent was removed by reduced pressure distillation at -0.090 MPa for 1 h to obtain epoxy resin glue. 0.72 g of polytetrahydrofuran, 0.01 g of 1,4-butanediol, 0.03 g of HDI, and 0.004 g of a tridentate ligand were mixed in 10 ml of tetrahydrofuran solvent, 0.02 g of dibutyltin dilaurate was added, and the mixture was reacted at 50° C. for 3 h. After the reaction, the solvent was removed by vacuum distillation at -0.090 MPa for 1 h to obtain a polyurethane glue; the obtained polyurethane glue was dissolved in 5 ml of dichloromethane, 2.3 mg of palladium acetate and the obtained epoxy resin glue were added, the mixture was stirred at 25° C. for 2 h, the solvent was removed by vacuum distillation, and the mixture was cured at 80° C. for 12 h to obtain a polyurethane epoxy polymer network.

[0094] Comparative Example 2

[0095] This comparative example provides a polyurethane epoxy polymer network, the preparation method of which comprises the following steps:

[0096] 0.79g of polytetrahydrofuran, 0.01g of 1,4-butanediol, and 0.12g of HDI were mixed in 10ml of tetrahydrofuran solvent. 0.02g of dibutyltin dilaurate was added, and the mixture was stirred at 50°C under argon for 3 hours. The mixture was then distilled under reduced pressure (-0.090 MPa, 15 minutes) to obtain a polyurethane. The resulting polyurethane and 0.14g of epoxy resin E51 were dissolved in 10ml of dichloromethane, stirred at 25°C for 1 hour, and distilled under reduced pressure at -0.090 MPa for 1 hour. After that, 0.034g of N,N-dimethyl-1,2-ethylenediamine was added, and the mixture was stirred at 25°C for 6 hours. The mixture was cured at 80°C for 12 hours to obtain a polyurethane epoxy polymer network.

[0097] Comparative Example 3

[0098] This comparative example provides a polyurethane epoxy polymer network, the preparation method of which comprises the following steps:

[0099] 0.15g of monodentate ligand, 0.14g of epoxy resin E51, and 0.034g of N,N-dimethyl-1,2-ethylenediamine were dissolved in 15ml of dichloromethane and reacted at 80°C for 12h. After the reaction, the solvent was removed by vacuum distillation at -0.090 MPa for 1h to obtain epoxy resin adhesive. 0.72g of polytetrahydrofuran, 0.01g of 1,4-butanediol, 0.03g of HDI, and 0.004g of tridentate ligand were mixed in 10ml of tetrahydrofuran solvent, 0.02g of dibutyltin dilaurate was added, and the mixture was reacted at 50°C for 3h. After the reaction, the solvent was removed by vacuum distillation at -0.090 MPa for 1h to obtain polyurethane adhesive. The obtained polyurethane adhesive was dissolved in 5ml of dichloromethane, the obtained epoxy resin adhesive was added, and the mixture was stirred at 25°C for 2h. After the solvent was removed by vacuum distillation, the mixture was cured at 80°C for 12h to obtain a polyurethane epoxy polymer network.

[0100] Figure 1 The infrared spectrum absorption (FTIR) diagram of the WPU-EP polyurethane epoxy polymer network prepared in Example 2, the SPU-EP polyurethane epoxy polymer network prepared in Comparative Example 1, and the CPU-EP polyurethane epoxy polymer network prepared in Comparative Example 2 shows that the 2120 cm-1 corresponding to the isocyanate group -1 and 912 cm corresponding to the epoxy group -1 The peaks near 3300-3600 cm completely disappeared in all three polymer networks, indicating that both HDI and E51 in the system had reacted completely. -1 、1660-1720cm -1 and 1010-1250cm -1 The peaks at 2850-2960 cm are assigned as the characteristic absorption peaks of NH and OH, C=O and COC groups, indicating the formation of carbamate groups and the introduction of a large number of hydroxyl groups in the system. -1 、1490-1550cm -1 and 810-830cm -1 The peak at 1450 cm-1 is attributed to the stretching vibration of the methylene and benzene rings and the bending vibration of the para-disubstituted benzene ring, indicating the successful integration of the polyurethane and epoxy resin segments into the network. -1 The peak at is only found in the spectra of WPU-EP and SPU-EP, indicating the existence of nodes in their networks.

[0101] Figure 4The stress-strain curves of the WPN polyurethane epoxy polymer network (WPU-EP) prepared in Example 2, the SPN polyurethane epoxy polymer network (SPU-EP) prepared in Comparative Example 1, the CPN polyurethane epoxy polymer network (CPU-EP) prepared in Comparative Example 2, and the linear polyurethane epoxy resin blend network (PU / EP blend) prepared in Comparative Example 3 at a tensile rate of 100 mm / min are shown. Figure 4 It can be seen that the presence of braided nodes greatly improves the mechanical properties of the copolymer network.

[0102] Performance testing:

[0103] Recovery rate: tested using GB / T2794 method.

[0104] Toughness: tested using GB / T 7124-2008 method.

[0105] Tensile strength: tested using GB / T 528-2009 method.

[0106] Elongation at break: tested using GB / T 528-2009 method.

[0107] The specific test results are shown in Table 1.

[0108] Table 1

[0109]

[0110] According to the data in Table 1, taking Examples 1-5 as an example, the toughness of the polyurethane epoxy polymer network of the present invention is 18.6-989.8 MJ / m 2 , tensile strength is 8.7-63.3 MPa, elongation at break is 276.4%-3104.6%, and Young's modulus is 33.2-174 MPa.

[0111] Analysis of Comparative Examples 1, 2, 3 and Example 2 shows that in Comparative Example 1, the polyurethane epoxy polymer network was prepared by supramolecular crosslinking, and the recovery rate of the system was reduced from 80.2% to 55.9%, and its toughness was reduced from 989.8 MJ / m 2 Down to 308 MJ / m 2 , its tensile strength decreased from 63.3 MPa to 25.4 MPa, its elongation at break decreased from 3104.6% to 1936.7%, and its Young's modulus decreased from 67.8 MPa to 66.3 MPa; in comparative example 2, a polyurethane epoxy polymer network was prepared by covalent crosslinking, and the recovery rate of the system decreased from 80.2% to 71.4%, and its toughness decreased from 989.8 MJ / m 2 Down to 142.4 MJ / m 2, its tensile strength decreased from 63.3 MPa to 25.8 MPa, its elongation at break decreased from 3104.6% to 770.5%, and Young's modulus increased from 67.8 MPa to 76.1 MPa; in comparative example 3, a polyurethane epoxy resin polymer network was obtained by blending strategy, and the recovery rate of the system decreased from 80.2% to 59.8%, and its toughness decreased from 989.8 MJ / m 2 Down to 4.9 MJ / m 2 , its tensile strength dropped from 63.3 MPa to 12.4 MPa, its elongation at break dropped from 3104.6% to 667.8%, and its Young's modulus dropped from 67.8 MPa to 21.9 MPa. This indicates that the presence of braided nodes effectively integrates linear polyurethane and epoxy resin chains, preventing the material's tendency to phase separate. The resulting polymer network balances hardness and elasticity, while exhibiting unique advantages in tensile strength and toughness.

[0112] Analysis of Examples 1-3 shows that the mechanical properties of the polyurethane epoxy polymer network with 5% braided nodes are better than those of the polyurethane epoxy polymer network with 1% and 10% braided nodes, indicating that a suitable node ratio in the system will help to improve the mechanical properties.

[0113] Analysis of Examples 2 and 4-5 shows that as the epoxy resin addition ratio increases, the system's toughness, tensile strength, and elongation at break gradually decrease, while the Young's modulus gradually increases, and the hardness improves. Throughout the system, the overall performance of the material can be continuously adjusted by adjusting the epoxy resin content to meet the needs of different application scenarios.

[0114] The above-described embodiments illustrate the polyurethane-epoxy polymer network, its preparation method, and its application. However, the present invention is not limited to these embodiments, and implementation of the present invention is not necessarily dependent on these embodiments. Those 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 polyurethane epoxy polymer network, characterized in that: The preparation method comprises the following steps: (1) Polyurethane is obtained by reacting polyol, small molecule chain extender, diisocyanate and tridentate ligand; (2) dissolving the polyurethane obtained in step (1) in an organic solvent, adding a divalent palladium compound and a monodentate ligand, and performing a coordination reaction; (3) adding epoxy resin monomer and curing agent to the reaction solution obtained in step (2), removing the solvent after mixing, and then curing to obtain the polyurethane epoxy polymer network; The tridentate ligand in step (1) is the following compound: ； The monodentate ligand in step (2) is selected from the following compounds: ； The mass ratio of the polyol to the tridentate ligand in step (1) is 30:2 to 69:2; The mass ratio of the polyurethane to the divalent palladium compound in step (2) is (250-400):1; The mass ratio of the polyurethane to the monodentate ligand in step (2) is (250-400): (1-9).

2. The preparation method according to claim 1, characterized in that The polyol is selected from polyols terminated with hydroxyl groups at both ends; The small molecule chain extender is a small molecule diol, and the small molecule diol includes any one of 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or 1,4-diol, or a combination of at least two thereof; The diisocyanate is selected from any one of hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate or dicyclohexylmethane diisocyanate, or a combination of at least two thereof.

3. The preparation method according to claim 1, characterized in that The polyol is selected from any one of polytetrahydrofuran, polyethylene glycol or polypropylene glycol, or a combination of at least two thereof; The mass ratio of the polyol to the small molecule chain extender in step (1) is (30-80): (1-5); The mass ratio of the polyol to diisocyanate in step (1) is (30-80): (3-15); The reaction in step (1) is carried out in the presence of a catalyst, wherein the catalyst is dibutyltin dilaurate; The mass ratio of the catalyst to the polyol is 1:(15-40); The reaction in step (1) is carried out in an organic solvent, wherein the organic solvent is selected from any one of tetrahydrofuran, N,N-dimethylformamide or 1,4-dioxane, or a combination of at least two thereof; The mass ratio of the organic solvent to the polyol is (500-2000): (30-80).

4. The preparation method according to claim 1, characterized in that The reaction temperature in step (1) is 40-60°C, and the reaction time is 3-12 hours; After the reaction in step (1) is completed, the solvent is removed by distillation under reduced pressure to obtain polyurethane; The reduced pressure distillation temperature is 30-50° C., the vacuum degree is -0.090 to -0.095 MPa, and the reduced pressure distillation time is 0.5 to 2 h.

5. The preparation method according to claim 1, characterized in that The divalent palladium compound in step (2) is selected from palladium acetate or palladium tetrafluoroborate; The organic solvent in step (2) is selected from any one of dichloromethane, N,N-dimethylformamide or acetonitrile, or a combination of at least two thereof; The mass ratio of the polyurethane to the organic solvent in step (2) is (250-400): (8000-10000); The temperature of the coordination reaction in step (2) is 20-30° C., and the time of the coordination reaction is 2-8 hours.

6. The preparation method according to claim 1, characterized in that The epoxy resin monomer in step (3) is a bisphenol A epoxy resin monomer; The bisphenol A epoxy resin monomer is selected from E51, E44 or E55; The curing agent in step (3) is selected from di-secondary amine compounds; The di-secondary amine compound is selected from any one of dimethylethylenediamine, N,N'-diethylethylenediamine, and N,N'-diisopropylethylenediamine, or a combination of at least two thereof.

7. The preparation method according to claim 1, characterized in that The mass ratio of the epoxy resin monomer in step (3) to the polyurethane in step (2) is (1-15):7; The mass ratio of the curing agent in step (3) to the polyurethane in step (2) is (0.2~3):

7.

8. The preparation method according to claim 1, characterized in that The solvent is removed in step (3) by vacuum distillation; The vacuum distillation temperature is 30-50°C, the vacuum degree is -0.080~-0.090Mpa, and the vacuum distillation time is 0.5~2h; The curing temperature in step (3) is 60-100°C and the curing time is 3-12h.

9. The polyurethane epoxy polymer network prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the polyurethane epoxy polymer network according to claim 9 in elastomeric materials or adhesives.

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