Method for self-growing super-tough thermosetting polyurethane

Abstract

The invention discloses a method for self-growing super-tough thermosetting polyurethane, and belongs to the technical field of plastic modification and processing. The preparation method comprises the following steps: mixing binary isocyanate, polyol and imidazole, carrying out temperature control reaction, precipitating by using excessive diethyl ether to obtain a product, and drying the product to obtain thermoplastic polyurethane containing imidazole urea bonds; the preparation method comprises the following steps: processing and forming thermoplastic polyurethane, respectively immersing the thermoplastic polyurethane into epoxy resin / diethyl ether solutions with different concentrations for swelling, taking out the thermoplastic polyurethane after the swelling is finished, and heating and curing the thermoplastic polyurethane to obtain the super-tough thermosetting polyurethane. Thermoplastic is subjected to in-situ conversion to generate thermosetting plastic based on a self-growth strategy of an imidazole-urea bond group, the flexibility of polyurethane and the firmness of epoxy resin are combined at the same time, a mechanical enhancement effect is generated, the material has the characteristics of firmness and toughness, the material can be processed through hot-melt extrusion molding, and the material has a good application prospect. The mode is the same as that of thermoplastic plastics, so that the processing difficulty of the thermosetting plastics is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic modification and processing, and in particular relates to a method for self-growing super-tough thermosetting polyurethane. Background Art

[0002] Thermosetting polymers are widely used in our daily lives due to their excellent mechanical properties, thermal stability and solvent resistance.

[0003] However, their cross-linked structure makes them impossible to process by hot-melt extrusion (melt spinning and fused deposition modeling 3D printing) or solvent-assisted molding (electrospinning and wet spinning), which greatly limits their shape design and application. In contrast, thermoplastic polymers are easy to process but are greatly limited by poor mechanical properties, thermal stability and solvent resistance. Therefore, it is extremely challenging to give thermoset materials the same excellent processing properties as thermoplastics.

[0004] In the past, although many efforts have been made to solve this problem, the results have mostly been unsatisfactory. For example, using photocurable groups as in-situ crosslinking points in the material is simple, but requires complex and expensive equipment; embedding fillers (fibers and nanoclay flakes) as thickeners to support the shape can achieve hot melt extrusion molding of thermosetting plastics, but the introduction of fillers not only makes the material impure, but also makes its elongation at break and toughness worse.

[0005] Recently, a method for hot melt extrusion of pure thermosets (polyester, polyurethane and epoxy resin) by using removable fillers (sodium chloride particles) was reported. However, this method is limited to the preparation of porous thermosets. Emerging vitrimers with covalent adaptive networks can endow cross-linked materials with melt extrusion capabilities and have been widely used in fused deposition modeling 3D printing. However, the reported materials usually have compromised mechanical properties, which may be due to the weak covalent network, which is designed to improve the rheological properties of the material and meet the melt flow behavior required for processing.

[0006] Overall, how to develop and process thermoplastics into strong and tough thermoset plastics to improve the performance of materials remains a considerable challenge. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing super-tough thermosetting polyurethane, which converts thermoplastic plastics into strong and tough thermosetting plastics in situ through the self-growth of imidazole-urea bond groups.

[0008] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0009] A method for self-growing super-tough thermosetting polyurethane comprises the following steps: mixing diisocyanate, polyol and imidazole, reacting the mixture under temperature control, precipitating the mixture with excess ether to obtain a product, and drying the product to obtain a thermoplastic polyurethane containing imidazole urea bonds; immersing the prepared thermoplastic polyurethane containing imidazole urea bonds in epoxy resin / ether solutions of different concentrations to swell the mixture, and after the swelling is completed, taking the mixture out and heating and curing the mixture to obtain a super-tough thermosetting polyurethane.

[0010] Furthermore, the diisocyanate is diphenylmethane diisocyanate.

[0011] Furthermore, the polyol is polytetramethylene glycol.

[0012] Furthermore, the imidazole is 4-hydroxymethylimidazole.

[0013] Furthermore, the molar ratio of the imidazole to the polyol is 0.05-20:1; the molar amount of the diisocyanate is the sum of the molar amounts of the imidazole and the polyol.

[0014] Furthermore, the epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin; in the epoxy resin / ether solution, the mass ratio of epoxy resin to ether is 0.01-10:1.

[0015] Furthermore, the temperature of the temperature-controlled reaction is 70° C. and the time is 6 hours.

[0016] Furthermore, the temperature of the heating curing is 50-100° C. and the time is 30-120 min.

[0017] Furthermore, the preparation method of any of the above-mentioned super-tough thermosetting polyurethanes comprises the following steps:

[0018] (1) placing polytetramethylene glycol in a reactor and drying it in a vacuum at 110° C. for 2 hours; then dissolving 4-(hydroxymethyl)imidazole in DMF and adding it to the reactor; then adding diphenylmethane diisocyanate and reacting at 70° C. for 6 hours; after the reaction is completed, precipitating the obtained product with an excess of ether, and then drying it in a vacuum at 40° C. for 24 hours to obtain a thermoplastic polyurethane containing imidazole urea bonds;

[0019] (2) hot-melt extrusion molding the obtained thermoplastic polyurethane containing imidazole urea bonds to obtain a sample;

[0020] (3) The obtained samples were immersed in excess epoxy resin / ether solutions of different concentrations for 60 min, the samples were taken out and heated at 80°C for 60 min to obtain super-tough thermosetting polyurethane.

[0021] Furthermore, step (2) hot melt extrusion molding includes melt spinning and melt deposition modeling 3D printing.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] 1) The present invention discloses a self-growth strategy based on imidazole-urea bond groups, which can convert thermoplastics into strong and tough thermosetting plastics in situ, break through the performance barriers of existing thermoplastics or thermosetting plastics, and give thermosetting materials the same excellent processing performance as thermoplastics.

[0024] 2) The thermoplastics based on imidazole-urea bonds of the present invention can be prepared by one-pot polymerization of commercially available reagents. The prepared thermoplastics are immersed in commercially available epoxy resins, and they can be self-grown into thermosetting plastics, making them easy to implement. The grown thermosetting plastics have excellent mechanical properties, thermal stability and chemical resistance.

[0025] 3) The present invention generates a thermosetting plastic by in-situ conversion of thermoplastics through a self-growth strategy based on imidazole-urea bond groups, while combining the flexibility of polyurethane and the firmness of epoxy resin to produce a mechanical reinforcement effect, making the material both firm and tough. The material can be processed by hot-melt extrusion in the same manner as thermoplastics, greatly reducing the difficulty of processing thermosetting plastics.

[0026] 4) The self-growing chemical composition based on the imidazole-urea linkage group of the present invention may also be used in other types of processing methods (such as wet / electrospinning) and polymer materials (such as polyolefins, polyesters and polyamides). BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The schematic diagram of the design of the in-situ growth of thermoplastics into strong and tough thermosetting plastics of the present invention includes: (a) a schematic diagram of the chemical reaction of synthesizing TPU with imidazole-urea part; (b) a schematic diagram of the chemical reaction of thermal dissociation of dynamic imidazole-urea to release isocyanate and imidazole; (c) a schematic diagram of the reaction of imidazole with epoxy resin to generate hydroxyl groups on the side chain; (d) a schematic diagram of the reaction of hydroxyl groups with isocyanate to generate crosslinking points; (e) a schematic diagram of the self-growth chemical reaction of TPU with linear molecules to CPU, with a crosslinking network using epoxy resin as a nutrient; and (f) a schematic diagram of hot melt extrusion molding of thermosetting plastics by self-growth chemistry.

[0028] Figure 2The present invention shows a method for growing polyurethane in an epoxy / ether solution and a diagram showing the effect after growth; wherein: (a) a swelling kinetics diagram of TPU in epoxy / ether nutrient solution with different epoxy concentrations (0%, 0.5%, 1.5%, 2.5%, 5%, 7.5%, 10%, 20% and 40%); (b) the effect of epoxy resin concentration on the growth index of the growing material, growth index: (Mgrown-Minitial) / Minitial; (c) a dissolution experiment photograph verifying the growth of TPU in CPU; and (d) a relationship diagram showing the effect of the growth index on the gel content of the growing material.

[0029] Figure 3 The mechanical properties of the samples of the thermoplastics of the present invention after different growth indices are shown in Figure 1; wherein (a) the stress-strain curves of the initial TPU and the grown CPU samples with different growth indices. (b) Figure 3 A zoomed-in view of the small strain range in (a) shows the tunability of the modulus through self-growth. (c) Dynamic mechanical thermal analysis (DMA) plot of the initial TPU and the grown CPU samples.

[0030] Figure 4 Figure 1 shows the thermosetting plastics used in the hot melt extrusion molding process in the examples; (a) Schematic diagram of the hot melt extrusion device. (b) Hot melt extruded TPU filaments. (c) Photographs of the dissolution experiment, which confirms the cross-linked structure of the filaments after growth. (d) Thermosetting filaments carrying a weight that is more than 160,000 times their own weight. (e) 3D printed thermosetting products in the shape of spider webs.

[0031] Figure 5 For TPU based on imidazole-urea bond 1 H NMR spectrum;

[0032] Figure 6 FTIR spectrum of TPU based on imidazole-urea bond;

[0033] Figure 7 The stress-strain curves of the imidazole-urea bond group TPU samples with different imidazole / poly(tetramethylene glycol) molar ratios;

[0034] Figure 8 The swelling kinetics of the sample of TPU based on imidazole-urea bond in pure ether;

[0035] Fig. 9 FTIR spectra of epoxy resin, initial TPU and growth materials with different growth indices;

[0036] Fig.10 This is a diagram of epoxy resin homopolymerization initiated by imidazole groups;

[0037] Fig.11 The mechanical properties diagram of TPU with different growth indexes;

[0038] Fig.12 Dynamic mechanical thermal analysis (DMA) of the initial TPU and the grown CPU samples, and the variation of tan δ with temperature. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with specific embodiments.

[0040] Materials used in the following specific embodiments are described.

[0041] Poly(tetramethylene glycol, Mn=1000 g / mol) was purchased from Aladdin.

[0042] Diphenylmethane diisocyanate was purchased from Wanhua Chemical Group.

[0043] 4-(Hydroxymethyl)imidazole, anhydrous N,N-dimethylformamide (DMF), anhydrous diethyl ether, and tetrahydrofuran (THF) were purchased from Sinopharm Reagents.

[0044] The following specific implementation method test method is described.

[0045] 1H nuclear magnetic resonance (1H NMR) spectra were recorded on a Bruker Avance 500 NMR spectrometer.

[0046] Fourier transform infrared (FTIR) analysis was performed on a Bruker VERTEX 70v spectrometer.

[0047] Gel permeation chromatography (GPC, Waters 1525) analysis was performed at a flow rate of 1 mL min-1 using tetrahydrofuran as the eluent and polystyrene as the standard.

[0048] DMA Q800 at 5 °C min -1 Dynamic mechanical analysis (DMA) was performed at a heating rate of 1.0 Hz.

[0049] On an electronic universal testing machine (SUNS), the -1 The tensile test was carried out at a tensile rate.

[0050] Example 1

[0051] Synthesis of imidazole-urea bonded thermoplastic polyurethane: polytetramethylene glycol (50 g, 0.05 mol) was placed in a 500 mL reactor and dried in a vacuum at 110 ° C for 2 hours; then 4-hydroxymethylimidazole (7.5 g, 0.075 mol) was dissolved in DMF (80 mL) and added to the reactor; diphenylmethane diisocyanate (31.25 g, 0.125 mol) was added and reacted at 70 ° C for 6 hours; after the reaction was completed, the obtained product was precipitated with excess ether and then vacuum dried at 40 ° C for 24 hours to obtain imidazole-urea bonded thermoplastic polyurethane (TPU, Mw = 14,694 g / mol, PDI = 2.28, measured by GPC). The obtained TPU sample was dissolved in 7 times THF and then cast into an aluminum dish. After drying at room temperature for 12 hours, a TPU film was obtained.

[0052] Swelling kinetics of TPU. The prepared TPU film was weighed and immersed in 100 times epoxy / ether solution with different epoxy concentrations (0, 0.5%, 1.5%, 2.5%, 5%, 7.5%, 10%, 20% and 40%). After a predetermined time interval, the film was taken out and re-weighed again. The swelling ratio (Sr) was calculated using the following formula.

[0053] Sr=(Mi-M0) / M0

[0054] where M0 and Mi are the masses of the film before and after immersion, respectively.

[0055] Self-growth of TPU towards CPU: The prepared TPU film (0.1 g) was immersed in an excess epoxy resin / ether solution (10 g) with different epoxy resin concentrations (0, 0.5%, 1.5%, 2.5%, 5%, 7.5%, 10%, 20% and 40%) for 60 minutes. Then, the film was taken out and heated at 80°C for 60 minutes to obtain a series of CPU films.

[0056] Gel fraction detection. Gel component test was performed by solvent extraction. The obtained CPU film (0.1 g) was immersed in an excess of tetrahydrofuran (10 mL) for 24 hours to remove non-crosslinked molecules in the film. After that, the film was dried in a vacuum at 40°C for 1 hour and then weighed. Their gel content was calculated using the following formula.

[0057] Gc=(Mse-M0) / M0

[0058] where M0 and Mse are the mass of the film before and after solvent extraction, respectively.

[0059] Hot melt extrusion: Hot melt extrusion was performed using a G5-ULTRA 3D printer with a heatable tank and extrusion nozzle (0.8 mm diameter). The TPU sample was cut into small pieces and added to a water tank. In order to give the sample better rheological properties, 20% of dioctyl phthalate was added to the sample; the extrusion temperature of the tank and nozzle was set to 130°C, and the extrusion speed was set to 50 mm / s. After completion, the obtained product was grown into a CPU using the same process as above.

[0060] The present invention can easily synthesize imidazole-based TPU (TPU) in a one-pot polymerization by reacting diphenylmethane diisocyanate, polytetramethylene glycol and 4-(hydroxymethyl)imidazole. Figure 1 a). 1H NMR and FTIR spectra confirmed its structure, such as Figure 5 and Figure 6 The molar ratio of imidazole / poly(tetramethylene glycol) was set to 1.5:1 because the TPU sample had better mechanical properties at this ratio. Figure 7 The linear molecular structure gives the initial TPU material excellent processing properties, especially suitable for hot melt extrusion molding. 4-(Hydroxymethyl)imidazole is used as a chain extender to introduce active imidazole-urea parts, which is crucial for the self-growth of thermoplastics into thermosetting plastics. Figure 1 As shown. Diphenylmethane diisocyanate was selected as the hard segment because aromatic isocyanates can promote the thermal dissociation of adjacent imidazole urea bonds compared to aliphatic isocyanates, which is conducive to chemical self-growth. In addition, the abundant π-π stacking bonds between aromatic / imidazole rings and hydrogen bonds between imidazole urea / urethane bonds can prevent the material from dissolving into nutrients and maintain its macroscopic integrity during the growth process. Polytetramethylene glycol, as a soft segment, can not only give the material flexibility and toughness, but also accelerate the diffusion of epoxy nutrients into the body matrix during the self-growth process. Therefore, the above molecular design ensures the in situ self-growth ability of thermoplastics, enabling them to form strong and tough thermosetting plastics.

[0061] The present invention uses the prepared TPU polymer film to study the self-growth behavior, and epoxy resin is used as a nutrient. In addition, the solvent is also an important factor in designing self-growth materials, which can not only promote the absorption of nutrients into the polymer, but also adjust the absorbed dosage. The present invention chooses ether as the solvent because ether has excellent swelling ability for TPU, but will never dissolve the sample. Figure 8 As shown in Figure 1, once immersed in pure ether, the TPU sample reaches swelling equilibrium within 10 minutes. After removing the ether, the sample completely recovers to its initial state with the same weight and size. This ensures the macroscopic integrity of the sample during the growth process.

[0062] The present invention conducts a self-growth experiment by immersing TPU samples in epoxy resin / ether solutions with different excess epoxy resin concentrations. The swelling kinetic curve shows that almost all the dissolved substances reach swelling equilibrium in about 60 minutes ( Figure 2 a), so the immersion time was set to 60 min for subsequent inspection. After immersion in the nutrient solution, the expanded sample was heated to 80 °C to remove the ether and insert the epoxy resin molecules into the polymer network to grow into a thermosetting material, such as Figure 1 As shown. FTIR spectrum confirmed the introduction of epoxy resin into the polymer ( Fig. 9 Here, the growth index is defined as (Mgrown-Minitial) / Minitial, where Mgrown and Minitial are the masses of the growing sample and the initial sample, respectively, and is used to study the effect of epoxy resin concentration on growth. Figure 2 As shown in (b), the growth exponent increases linearly with the epoxy concentration, indicating that the growth can be easily tuned and precisely controlled by varying the epoxy concentration.

[0063] Example 2

[0064] The dissolution experiment was used to verify the formation of cross-linked structure after TPU growth.

[0065] like Figure 2 As shown in Figure c, the initial TPU sample can be completely dissolved in tetrahydrofuran; however, after undergoing the autogenous process, the sample only swells but does not dissolve. This indicates that the thermoplastic is successfully converted into a thermoset. Figure 2 As shown in Figure d, the gel fraction test shows that the gel content of the sample increases with the increase of the growth index until it reaches an equilibrium value of 96% when the growth index is 20%. This change behavior is highly correlated with the content of imidazole-urea bond groups in the initial TPU molecules. Figure 1 The maximum growth index of the prepared TPU sample was calculated to be 16.6% with the growth chemistry and molecular design described in the previous section, at which all imidazole-urea bond groups participated in the crosslinking reaction and produced a highly crosslinked network. This value is consistent with the initial equilibrium site (20%) described in the gel fraction test above ( Figure 2 d). Nevertheless, further increasing the growth index does not lead to a decrease in gel content, indicating that excess epoxy resin can also be integrated into the network. This is mainly because the homopolymerization of epoxy resin forms a highly cross-linked polyether network initiated by Lewis base (imidazole groups) ( Fig.10 ). Therefore, the above results confirm the feasibility of realizing thermosetting plastics by in situ self-growth of thermoplastics using imidazole-urea linkage groups.

[0066] Due to the generation of covalent cross-linked structures, the transformation of TPU to CPU induced by the self-growth strategy can significantly improve the mechanical and thermomechanical properties of the material. The stress-strain curves of the samples before and after growth are shown in Figure 2. Figure 3 The initial TPU sample has a tensile strength of 7.3 ± 1.0 MPa, a modulus of 34.1 ± 3.2 MPa, an elongation at break of 728.5 ± 107.4%, and a toughness of 34.9 ± 1.5 MJ / m 3 ( Figure 3 a, Fig.11 ). When the growth index is only 1%, the elongation at break and toughness increase to 868.8±23.9% and 43.4±1.4 MJ / m, respectively. 3 As the growth index increases from 1% to 8%, the strength and toughness increase significantly to 38.8±1.7MPa and 99.3±6.2MJ / m 3 , while still maintaining a high elongation at break of 574.8 ± 29.4%. Further increasing the growth index decreases the mechanical properties, but continues to increase the modulus ( Figure 3 b, Fig.11 ). The modulus can be increased to 613.7 ± 115.2 MPa, which is 18 times that of the initial TPU, indicating that the hardness of the material can be easily adjusted as needed. In addition, the thermomechanical properties are also significantly improved. Figure 3 c and Fig.12 As shown in Figure 3, the mechanical properties decrease rapidly with increasing temperature, and the material is able to flow at around 120°C. In contrast, the grown material still has comparable mechanical properties and can maintain its macroscopic shape even when the temperature rises to 200°C, indicating that the grown material has better thermomechanical properties and thermal stability.

[0067] Example 3

[0068] Applicable for processing thermosetting plastics by hot melt extrusion.

[0069] Hot melt extrusion using a fused deposition modeling 3D printer with a heated tank and nozzle ( Figure 4 a), and added TPU based on imidazole-urea bond in the tank, and then hot melt extruded to obtain filaments. Extrusion temperature is an important parameter of the extrusion process, because at low temperature, the high elasticity of the melt makes it impossible to extrude, while at high temperature, the low viscosity makes it too fluid-like to form filaments. After many attempts, the extrusion temperature of the water tank and nozzle was set to 130℃ so that the TPU sample could be easily extruded to produce filaments ( Figure 4 b) Through the above self-growth process, thermosetting filaments can be obtained. Dissolution experiments confirmed its cross-linked network ( Figure 4c). In addition, the filaments can carry objects weighing more than 160,000 times their own weight ( Figure 4 d), indicating its excellent mechanical properties. By changing the digital model, 3D printed thermoset products with complex three-dimensional shapes (spider webs) can be easily obtained. The above results show that this strategy can be used for melt spinning and fused deposition modeling 3D printing of strong and tough thermoset plastics.

[0070] The present invention discloses a self-growth strategy based on imidazole-urea bond groups, which can convert thermoplastics into strong and tough thermosetting plastics in situ, and then introduces its application in hot melt extrusion molding of thermosetting plastics. Thermoplastics based on imidazole-urea bonds can be easily prepared by one-pot polymerization of commercially available reagents. By immersing thermoplastics in commercially available epoxy resins, they can be easily self-grown into thermosetting plastics, making them easy to implement. The grown thermosetting plastics have excellent mechanical properties, thermal stability and chemical resistance. In addition, self-growing chemical compositions based on imidazole-urea bond groups have the potential to be used in other types of processing methods (such as wet / electrospinning) and polymer materials (such as polyolefins, polyesters and polyamides).

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for self-growing ultra-tough thermosetting polyurethane, characterized in that: Diisocyanate, polyol and imidazole are mixed, reacted under temperature control, and then precipitated with excess ether to obtain a product, which is then dried to obtain a thermoplastic polyurethane containing imidazole urea bonds. The prepared thermoplastic polyurethane containing imidazole urea bonds is immersed in epoxy resin / ether solutions of different concentrations for swelling, and after the swelling is completed, it is taken out and heated for curing to obtain a super-tough thermosetting polyurethane.

2. The method for self-growing super-tough thermosetting polyurethane according to claim 1, characterized in that: The diisocyanate is diphenylmethane diisocyanate.

3. The method for self-growing super-tough thermosetting polyurethane according to claim 1, characterized in that: The polyol is polytetramethylene glycol.

4. The method for self-growing super-tough thermosetting polyurethane according to claim 1, characterized in that: The imidazole is 4-hydroxymethylimidazole.

5. The method for self-growing super-tough thermosetting polyurethane according to claim 1, characterized in that: The molar ratio of the imidazole to the polyol is 0.05-20:1; the molar amount of the diisocyanate is the sum of the molar amounts of the imidazole and the polyol.

6. The method for self-growing super-tough thermosetting polyurethane according to claim 1, characterized in that: The epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin and bisphenol S epoxy resin; in the epoxy resin / ether solution, the mass ratio of epoxy resin to ether is 0.01-10:

1.

7. The method for self-growing super-tough thermosetting polyurethane according to claim 1, characterized in that: The temperature of the temperature-controlled reaction is 70° C. and the time is 6 hours.

8. The method for self-growing super-tough thermosetting polyurethane according to claim 1, characterized in that: The temperature of the heating curing is 50-100° C. and the time is 30-120 minutes.

9. The method for self-growing super-tough thermosetting polyurethane according to any one of claims 1 to 8, characterized in that: Here are the steps: (1) placing polytetramethylene glycol in a reactor and drying it in a vacuum at 110° C. for 2 hours; then dissolving 4-(hydroxymethyl)imidazole in DMF and adding it to the reactor; then adding diphenylmethane diisocyanate and reacting at 70° C. for 6 hours; after the reaction is completed, precipitating the obtained product with an excess of ether, and then drying it in a vacuum at 40° C. for 24 hours to obtain a thermoplastic polyurethane containing imidazole urea bonds; (2) hot-melt extrusion molding the obtained thermoplastic polyurethane containing imidazole urea bonds to obtain a sample; (3) The obtained samples were immersed in excess epoxy resin / ether solutions of different concentrations for 60 min, the samples were taken out and heated at 80°C for 60 min to obtain super-tough thermosetting polyurethane.

10. The method for self-growing super-tough thermosetting polyurethane according to claim 9, characterized in that: Step (2) hot melt extrusion molding includes melt spinning and melt deposition modeling 3D printing.

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