A polyurethane material and its preparation method

Abstract

The present invention provides a polyurethane material and a preparation method thereof, belonging to the technical field of polymer materials. By incorporating different metal ions (divalent metals and trivalent metals) and corresponding different ligands (chain extenders) into the polymer network structure, the present invention not only facilitates the construction of a more robust physical crosslinking network, forms metal coordination bonds, and significantly improves the mechanical properties of the material, but also can flexibly regulate the mechanical properties of supramolecular polyurethanes; and due to the differences in metal coordination bonds, different energy dissipation systems are constructed, so different embodiments exhibit different mechanical properties. Therefore, the polyurethane material prepared by the present invention has both adjustable mechanical properties, such as high strength, high toughness, and extraordinary stretchability, as well as the film-forming property of polymer materials, excellent heat resistance, etc., and is expected to be applied in emerging fields such as flexible electronics and robotics, and provides new ideas and insights for the development of the next generation of supramolecular polyurethane materials with excellent mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a polyurethane material and a preparation method thereof. Background Art

[0002] Polyurethane has attracted much attention due to its excellent comprehensive properties, recyclability and broad application prospects, and has broad application prospects in the fields of aerospace, automotive, textile, construction, medical, intelligent detection, etc. However, as one of the most common polymer materials in daily life, most of the currently commercialized traditional polyurethane materials are cross-linked by irreversible covalent bonds, with complex preparation processes, extremely low strength and toughness matching coefficients of the materials, and it is difficult to meet the actual application requirements of many emerging fields, resulting in waste of resources and environmental pollution. Therefore, one of the key scientific problems currently faced in the field of polymer materials is how to develop high-performance polyurethane materials with strength and toughness through reasonable molecular structure design. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a polyurethane material and a preparation method thereof. The polyurethane material prepared by the present invention has both high strength and high toughness.

[0004] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a preparation method of a polyurethane material, comprising the following steps:

[0006] Mixing a polyester polyol, a diisocyanate, an organic solvent and a catalyst to carry out a prepolymerization reaction to obtain a polyurethane prepolymer;

[0007] Mixing the polyurethane prepolymer with a first chain extender to carry out a first chain extension reaction to obtain a first chain extension product; the first chain extender includes a diamine chain extender or a diol chain extender;

[0008] Mixing the first chain extension product, a metal salt and an organic solvent to carry out a complexation reaction to obtain a complexation product; the metal salt includes a divalent metal salt and a trivalent metal salt;

[0009] Dropping a second chain extender into the complexation product to carry out a second chain extension reaction to obtain a second chain extension product; the second chain extender includes a small molecule diamine chain extender;

[0010] Shaping the second chain extension product to obtain the polyurethane material.

[0011] Preferably, the molar ratio of the polyester polyol to the diisocyanate is 1:1 to 3.

[0012] Preferably, the diamine chain extender includes one or more of 2,6-dihydroxypyridine, 4,4'-dihydroxy-2,2'-bipyridine, 2,6-diaminopyridine, 6,6'-diamino-2,2'-bipyridine, and 2,4-diamino-6-hydroxypyrimidine, and the diol chain extender includes 2-urea-4[H]-pyrimidinone-2-amino-2-methyl-1,3-propanediol.

[0013] Preferably, the molar ratio of the diisocyanate to the first chain extender is 2-6:1.

[0014] Preferably, the metal element in the divalent metal salt includes Mn, Zn, or Cu, and the metal element in the trivalent metal salt includes Fe, Eu, or Tb.

[0015] Preferably, the molar ratio of the metal salt to the first chain extender is 0-5:1, and the molar amount of the metal salt is not 0.

[0016] Preferably, the temperature of the complexation reaction is 40-100 °C, and the time is 1 h-15 h.

[0017] Preferably, the small molecule diamine chain extender includes one or more of polyetheramine D230, adipic dihydrazide, terephthalic dihydrazide, 1,8-octanediamine, m-phenylenediamine, 4,4'-diaminodiphenylamine, 4,4'-dithiobis(diphenylamine), and o-xylenediamine.

[0018] Preferably, the molar ratio of the diisocyanate to the second chain extender is 2-6:1.

[0019] The present invention also provides a polyurethane material prepared by the preparation method described in the above technical solution.

[0020] The present invention provides a preparation method of a polyurethane material, including the following steps: mixing a polyester polyol, a diisocyanate, an organic solvent, and a catalyst to carry out a prepolymerization reaction to obtain a polyurethane prepolymer; mixing the polyurethane prepolymer with a first chain extender to carry out a first chain extension reaction to obtain a first chain extension product; the first chain extender includes a diamine chain extender or a diol chain extender; mixing the first chain extension product, a metal salt, and an organic solvent to carry out a complexation reaction to obtain a complexation product; the metal salt includes a divalent metal salt and a trivalent metal salt; dropping a second chain extender into the complexation product to carry out a second chain extension reaction to obtain a second chain extension product; the second chain extender includes a small molecule diamine chain extender; shaping the second chain extension product to obtain the polyurethane material.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The present invention provides a method for preparing a polyurethane material. Since different metal ligand bonds have different dissociation time scales, different types of metal ions can be used to establish a time hierarchy of energy dissipation in the material. In the present invention, by incorporating different metal ions (divalent metals and trivalent metals) and corresponding different ligands (chain extenders) into the polymer network structure, it is not only beneficial to construct a stronger physical cross-linking network, form metal coordination bonds, and significantly improve the mechanical properties of the material, but also can flexibly regulate the mechanical properties of supramolecular polyurethane; and due to the differences in metal coordination bonds, different energy dissipation systems are constructed, so different embodiments exhibit different mechanical properties. Therefore, the polyurethane material prepared by the present invention has both adjustable mechanical properties, such as high strength, high toughness and extraordinary stretchability, as well as film-forming properties of polymer materials, excellent heat resistance and other characteristics, and is expected to be applied to emerging fields such as flexible electronics and robotics, and provides new ideas and insights for the development of the next generation of supramolecular polyurethane materials with excellent mechanical properties.

[0023] The strengthening mechanism of the polyurethane material enhanced by metal coordination bonds in the present invention can be summarized as the following process:

[0024] 1. During the stretching process under small strain, sacrificial bonds will break to prevent local stress concentration during stretching, thereby promoting molecular chain orientation;

[0025] 2. Immediately afterwards, during the orientation process, dynamic sacrificial bonds can be reconstructed from the breakage;

[0026] 3. With further stretching, those re-established sacrificial bonds will break again, thereby dissipating energy and further promoting the consistent orientation of molecular chains;

[0027] 4. Finally, the strength, toughness and stretchability of the supramolecular polyurethane are significantly enhanced due to sufficient energy dissipation under large strain.

[0028] Moreover, the preparation method of the present invention has the advantages of simplicity, high efficiency, safety, environmental protection, etc. The prepared polyurethane material has both high strength, high toughness and extraordinary stretchability, as well as film-forming properties of polymer materials, excellent heat resistance and other characteristics.

[0029] Furthermore, when the first chain extender is 2-urea-4[H]-pyrimidinone-2-amino-2-methyl-1,3-propanediol (UPy-(OH)2) and the metal salt is a trivalent metal salt, the obtained polyurethane material is a poly(urea-carbamate) crosslinked by multiple dynamic bonds in cooperation. The ureidopyrimidinone UPy groups (quadruple hydrogen bonds) in the polymer segments form quadruple hydrogen bond interactions through self-assembly, which can not only induce phase separation to form a hard and soft segment structure, but also form stable microcrystals at ambient temperature through π-π stacking interactions, further improving the mechanical strength of the polyurethane material. In addition, the incorporation of metal iron ions helps to construct a stronger physical crosslinking network, forming metal coordination bonds, significantly improving the mechanical properties and further enhancing the crosslinking. The present invention introduces the synergistic effect of metal coordination bonds and quadruple hydrogen bonds to prepare a heat-resistant supramolecular polyurethane material with high strength and high toughness. The dynamic hierarchical domains rich in coordination bonds and hydrogen bonds can not only act as rigid fillers to reinforce the elastomer, but also undergo deformation and dissociation to fully dissipate energy. The synergistic effect of the dual supramolecular bonds endows the material with outstanding mechanical properties, which is of great significance and value for broadening the application of poly(urea-carbamate) materials in the fields of aerospace, automotive, textile, construction, medical, intelligent detection, etc.

[0030] Furthermore, the present invention limits the molar ratio of the metal salt to the first chain extender, thereby limiting the content and type of metal coordination bonds, and further prepares a material with strong elasticity and adjustable dynamic mechanical properties. Description of the Drawings

[0031] Figure 1 Infrared spectra of Examples 1-5;

[0032] Figure 2 Schematic diagram of the stress-strain curve summary of Examples 1-5;

[0033] Figure 3 Stress-strain curves of Example 4 at different tensile rates;

[0034] Figure 4 Schematic diagram of the thermogravimetric curve of Example 4;

[0035] Figure 5 Stress-strain curves of Example 1 and Comparative Examples 1-2 at the same tensile rate;

[0036] Figure 6 Atomic force microscope (AFM) image of SPUU-Fe / UPy;

[0037] Figure 7 Stress-strain curves of the materials obtained in Example 4 and Examples 6-8;

[0038] Figure 8It is the stress-strain curve of SPUU-Zn / UPy at different stretching rates. Specific embodiments

[0039] The present invention provides a method for preparing a polyurethane material, comprising the following steps:

[0040] Mixing a polyester polyol, a diisocyanate, an organic solvent, and a catalyst for a prepolymerization reaction to obtain a polyurethane prepolymer;

[0041] Mixing the polyurethane prepolymer with a first chain extender for a first chain extension reaction to obtain a first chain extension product; the first chain extender includes a diamine chain extender or a diol chain extender;

[0042] Mixing the first chain extension product, a metal salt, and an organic solvent for a complexation reaction to obtain a complexation product; the metal salt includes a divalent metal salt and a trivalent metal salt;

[0043] Dropping a second chain extender into the complexation product for a second chain extension reaction to obtain a second chain extension product; the second chain extender includes a small molecule diamine chain extender;

[0044] Shaping the second chain extension product to obtain the polyurethane material.

[0045] In the present invention, unless otherwise specified, the raw materials used are all commercially available products in the art.

[0046] The present invention mixes a polyester polyol, a diisocyanate, an organic solvent, and a catalyst for a prepolymerization reaction to obtain a polyurethane prepolymer.

[0047] In the present invention, the molar ratio of the polyester polyol to the diisocyanate is preferably 1:1 to 3, more preferably 1:2.

[0048] In the present invention, the polyester polyol preferably includes one or more of polycarbonate diol, polycaprolactone diol, adipic acid-based polyester polyol, succinic acid-based polyester polyol, glutaric acid-based polyester polyol, sebacic acid-based polyester polyol, glycerol, and sorbitol.

[0049] In the present invention, the molecular weight of the polyester polyol is preferably 1000 to 3000, more preferably 1500 to 2000.

[0050] In the present invention, the polyester polyol is preferably dehydrated and dried before use. The temperature of the dehydration and drying is preferably 100 to 150 °C, and the time is preferably 60 to 150 min. The dehydration and drying are preferably carried out in an oil bath. Preferably, the polyester polyol is placed in a three-necked flask with an electric stirrer, and nitrogen is introduced for the dehydration and drying, and the effect is to effectively inhibit the interference of moisture.

[0051] After the water removal and drying, the present invention preferably further includes natural cooling to 60 - 100 °C for standby.

[0052] In the present invention, the diisocyanate preferably includes one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), and 4,4'-dicyclohexylmethane diisocyanate (HMDI).

[0053] In the present invention, the organic solvent preferably includes one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), toluene, tetrahydrofuran (THF), and N-methylpyrrolidone (NMP).

[0054] In the present invention, the dosage ratio of the diisocyanate to the organic solvent is preferably 20 - 100 mmol: 20 - 200 mL.

[0055] In the present invention, the catalyst is preferably an amine catalyst or an organometallic catalyst. The amine catalyst preferably includes one or more of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, triethylamine, and N,N-dimethylbenzylamine; the organometallic catalyst preferably includes one or more of dibutyltin dilaurate (DBTDL), stannous octoate, zinc octoate, and bismuth octoate.

[0056] In the present invention, the dosage ratio of the diisocyanate to the catalyst is preferably 20 - 100 mmol: 0.01 - 0.05 g.

[0057] In the present invention, the temperature of the prepolymerization reaction is preferably 60 - 100 °C, more preferably 70 - 80 °C, and the time is preferably 2 - 5 h, more preferably 3 - 4 h. The prepolymerization reaction is preferably carried out in an N2 atmosphere.

[0058] After the prepolymerization reaction is completed, the present invention preferably adds the organic solvent to the obtained product again, and controls the dosage of the organic solvent to control the viscosity of the reactants to prevent gelation, thereby obtaining the polyurethane prepolymer.

[0059] In the present invention, the dosage ratio of the diisocyanate to the organic solvent added again is preferably 20 - 100 mmol: 5 - 20 mL.

[0060] The present invention preferably mixes the polyester polyol, diisocyanate, and organic solvent first, and then drops the catalyst.

[0061] After obtaining the polyurethane prepolymer, the present invention mixes the polyurethane prepolymer with a first chain extender to carry out a first chain extension reaction to obtain a first chain extension product; the first chain extender includes a diamine chain extender or a diol chain extender.

[0062] In the present invention, the diamine chain extender preferably includes one or more of 2,6-dihydroxypyridine, 4,4'-dihydroxy-2,2'-bipyridine, 2,6-diaminopyridine, 6,6'-diamino-2,2'-bipyridine, and 2,4-diamino-6-hydroxypyrimidine, and the diol chain extender preferably includes 2-urea-4[H]-pyrimidinone-2-amino-2-methyl-1,3-propanediol (UPy-(OH)2).

[0063] In the present invention, when the first chain extender is a solid, it is preferably dissolved in an organic solvent and ultrasonically treated until the solid chain extender is completely dissolved, and then the dissolved mixed solution is dropped into the reactor. The present invention has no special limitation on the type of the organic solvent, and an organic solvent well-known to those skilled in the art can be used. Specifically, the mass concentration of the dissolved solution is preferably 0.02 - 0.1 g / mL, and the present invention preferably drops the solution into the polyurethane prepolymer.

[0064] In the present invention, the molar ratio of the diisocyanate to the first chain extender is preferably 2 - 6:1.

[0065] In the present invention, the temperature of the first chain extension reaction is preferably 60 - 100 °C, more preferably 70 - 80 °C, the time is preferably 1 - 12 h, more preferably 6 - 10 h, the first chain extension reaction is preferably carried out in an N2 atmosphere, and the first chain extension reaction belongs to an addition reaction, and -NCO and -OH react to form a carbamate bond during the reaction process.

[0066] After obtaining the first chain extension product, the present invention mixes the first chain extension product, a metal salt, and an organic solvent to carry out a complexation reaction to obtain a complexation product; the metal salt includes a divalent metal salt and a trivalent metal salt.

[0067] In the present invention, the metal element in the divalent metal salt preferably includes Mn, Zn, or Cu, and the metal element in the trivalent metal salt preferably includes Fe, Eu, or Tb.

[0068] In the present invention, the divalent metal salt preferably includes MnCl2, ZnCl2, or CuCl2; the trivalent metal salt preferably includes FeCl3·6H2O, EuCl3, or TbCl3·6H2O.

[0069] In the present invention, the molar ratio of the metal salt to the first chain extender is preferably 0 - 5:1, and the molar amount of the metal salt is not 0.

[0070] In the present invention, the temperature of the complexation reaction is preferably 40 to 100 °C, more preferably 60 to 80 °C, and the time is preferably 1 to 15 h, more preferably 5 to 10 h. During the complexation reaction, metal ions will complex with the first chain extender to form a coordination effect. Specifically, for example, the metal salt contains trivalent metal ions and the first chain extender contains UPy groups, and the trivalent metal ions form metal coordination bonds with the N and O atoms on the six-membered ring of the UPy group.

[0071] In the present invention, it is preferred to first mix the metal salt with an organic solvent to obtain a mixed solution, and then drop the mixed solution into the first chain-extended product. In the present invention, the concentration of the mixed solution is preferably 0.1 g / mL. The present invention has no special limitation on the type of the organic solvent, and a scheme well-known to those skilled in the art can be adopted. In the present invention, the mixing is preferably ultrasonic, and the present invention has no special limitation on the parameters of the ultrasonic wave.

[0072] In the present invention, the dropping rate is preferably 0.5 to 1.0 mL / min. The dropping is to prevent the "agglomeration" phenomenon caused by too fast reaction, and at the same time can control the reaction rate and promote the full progress of the reaction.

[0073] In the present invention, when the first chain extender is preferably (UPy-(OH)2) and the metal salt is preferably a trivalent metal salt, the obtained polyurethane material is a poly(urea-carbamate) crosslinked by multiple dynamic bonds in cooperation.

[0074] After obtaining the complexation product, the present invention drops the second chain extender into the complexation product for a second chain extension reaction to obtain a second chain-extended product; the second chain extender includes a small molecule diamine chain extender.

[0075] In the present invention, the small molecule diamine chain extender preferably includes one or more of polyetheramine D230, adipic dihydrazide, terephthalic dihydrazide, 1,8-octanediamine, m-phenylenediamine, 4,4'-diaminodiphenylamine, 4,4'-dithiobis(diphenylamine), and o-xylenediamine.

[0076] In the present invention, the molar ratio of the diisocyanate to the second chain extender is preferably 2 to 6:1.

[0077] In the present invention, the temperature of the second chain extension reaction is preferably 40 to 100 °C, more preferably 60 to 80 °C, and the time is preferably 2 to 6 h, more preferably 3 to 5 h. The second chain extension reaction is preferably carried out in an N2 atmosphere. The second chain extension reaction is an addition reaction, and the amino -NH2 on the small molecule diamine chain extender reacts with the -NCO group on the isocyanate-terminated prepolymer to form a ureido group (-NH-C=O-NH-).

[0078] In the present invention, the dropping rate is preferably 0.5 - 1.0 mL / min. The dropping is to prevent the "agglomeration" phenomenon caused by too fast reaction, and at the same time can control the reaction rate and promote the full progress of the reaction.

[0079] The present invention does not adopt the one-pot method, but adopts stepwise chain extension. Its advantages are as follows: 1. Adding two chain extenders step by step can ensure that the two chain extenders react completely and fully during the corresponding reaction processes; 2. If the two chain extenders are added simultaneously, both of them carry atoms that can form hydrogen bonds, and they may form hydrogen bond interactions between them, inhibiting and interfering with the progress of the reaction.

[0080] After obtaining the second chain extension product, the present invention shapes the second chain extension product to obtain the polyurethane material.

[0081] In the present invention, the shaping preferably includes the following steps:

[0082] Pour the second chain extension product into a polytetrafluoroethylene mold, and perform drying treatment under vacuum at 60 - 100 °C for 24 - 72 h to remove the residual solvent.

[0083] The present invention also provides a polyurethane material prepared by the preparation method described in the above technical solution.

[0084] In order to further illustrate the present invention, the following examples are used to describe in detail the polyurethane material and its preparation method provided by the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0085] Example 1

[0086] (1) First, weigh (50 mmol, 100.0 g) of polycarbonate diol (PCDL-2000) with a molecular weight of 2000 g / mol and place it in a three-necked flask equipped with a stirrer. Heat and stir it in an oil bath at a temperature of 110 °C, and introduce nitrogen for 60 min.

[0087] (2) Secondly, lower the temperature of the oil bath to 80 °C. After the temperature cools down to 80 °C, weigh out (100 mmol, 16.82 g) of hexamethylene diisocyanate (HDI, 168.2 g / mol), and simultaneously measure 100 mL of N,N-dimethylformamide (DMF) as the solvent. After mixing the two evenly, add them to a three-necked flask. To promote the full reaction of the diisocyanate and polyol, add 0.05 g of the catalyst dibutyltin dilaurate (DBTDL) dropwise. This step is the prepolymerization reaction. Heat and stir in an oil bath at 80 °C and introduce nitrogen. The reaction time is 4 h. Then add 10 mL of DMF to appropriately control the viscosity of the reactants to prevent gelation, and obtain a polyurethane prepolymer. The molar ratio of HDI to PCDL-2000 is 2:1.

[0088] (3) After the prepolymer is prepared, keep the temperature unchanged. Weigh out (25 mmol, 10.0 g) of 2-ureido-4[H]-pyrimidinone-2-amino-2-methyl-1,3-propanediol (UPy-(OH)2) as the first chain extender, and measure 100 mL of DMF (ensuring that the concentration of the solution (the mixture of the solvent and solute) is 0.1 g / mL). Ultrasonically treat until completely dissolved to obtain a milky white solution, and then drop it into the three-necked flask. Continue to stir in an oil bath at 80 °C and introduce nitrogen for 5 h. Note: The molar ratio of HDI to UPy-(OH)2 is 4:1.

[0089] (4) After the chain extension reaction is completed, slowly add the second chain extender dropwise at a rate of 1.0 mL / min for further chain extension. Adjust the temperature of the oil bath to 50 °C. After the temperature cools down to 50 °C, weigh out (25 mmol, 5.75 g) of polyetheramine D230. Continue to stir in an oil bath at 50 °C and introduce nitrogen. The reaction time is about 6 h until the chain extender completely participates in the reaction. Note: The molar ratio of HDI to D230 is 4:1.

[0090] (5) Note: The molar ratio of the metal salt solid to the first chain extender in Example 1 is 0:1, that is, Example 1 does not contain trivalent metal salt solid.

[0091] (6) After the reaction is completed, pour the mixed solution into a polytetrafluoroethylene mold and perform vacuum drying at 85 °C for 72 h to remove the residual solvent. The sample is named Example 1.

[0092] Example 2

[0093] (1) It is consistent with steps 1 to 3 of Example 1.

[0094] (2) After the above chain extension reaction is completed, the temperature is lowered to 40 °C. Then, weigh ferric chloride hexahydrate FeCl3·6H2O (8.33 mmol, 1.35 g, molecular weight 162.2 g / mol), and simultaneously measure 5 mL of the organic solvent DMF. Dissolve the solid FeCl3·6H2O in the solvent DMF, and perform ultrasonic treatment until it is completely dissolved. The solution is reddish-brown, and then add it to the reaction flask. Continue stirring in an oil bath at 50 °C and introduce nitrogen. The reaction time is 10 h. Note: The molar ratio of FeCl3·6H2O to UPy-(OH)2 in Example 2 is 25:8.33 (Approximately 3:1) 。

[0095] (3) After the complexation reaction is completed, slowly (at a rate of 1 mL / min) add polyetheramine D230 for further chain extension. Raise the temperature of the oil bath to 50 °C, weigh (25 mmol, 5.75 g) of polyetheramine D230, continue stirring in an oil bath at 50 °C and introduce nitrogen. The reaction time is 6 h until the chain extension reaction is complete. Note: The molar ratio of HDI to D230 is 4:1

[0096] (4) After the reaction is completed, pour the mixture into a polytetrafluoroethylene mold, and carry out vacuum drying treatment at 85 °C for 72 h to remove the residual solvent. The sample is named Example 2

[0097] Example 3

[0098] (1) It is consistent with Steps 1-3 of Example 1

[0099] (2) After the above chain extension reaction is completed, the temperature is lowered to 40 °C. Then, weigh ferric chloride hexahydrate FeCl3·6H2O (12.5 mmol, 2.03 g, molecular weight 162.2 g / mol), and simultaneously measure 5 mL of the organic solvent DMF. Dissolve the solid FeCl3·6H2O in the solvent DMF, and perform ultrasonic treatment until it is completely dissolved. The solution is reddish-brown, and then add it to the reaction flask. Continue stirring in an oil bath at 50 °C and introduce nitrogen. The reaction time is 10 h. Note: The molar ratio of FeCl3·6H2O to UPy-(OH)2 in Example 3 is 0.5:1

[0100] (3) After the complexation reaction is completed, slowly (the dropping rate is 1.0 mL / minml / min) add polyetheramine D230 for further chain extension. Raise the temperature of the oil bath to 50 °C, weigh (25 mmol, 5.75 g) of polyetheramine D230, continue stirring in an oil bath at 50 °C and introduce nitrogen. The reaction time is 6 h until the chain extension reaction is complete. Note: The molar ratio of HDI to D230 is 4:1

[0101] (4) After the reaction is completed, pour the mixed solution into a polytetrafluoroethylene mold, and carry out vacuum drying treatment at 85 °C for 72 h to remove the residual solvent. The sample is named Example 3.

[0102] Example 4

[0103] (1) It is consistent with Steps 1 to 3 of Example 1.

[0104] (2) After the above chain extension reaction is completed, lower the temperature to 40 °C, and then weigh ferric chloride hexahydrate FeCl3·6H2O (25 mmol, 4.06 g, molecular weight 162.2 g / mol). At the same time, measure 10 mL of the organic solvent DMF, dissolve the solid FeCl3·6H2O in the solvent DMF, and perform ultrasonic treatment until completely dissolved. The solution is reddish-brown and add it to the reaction flask. Continue stirring in an oil bath at 50 °C and introduce nitrogen. The reaction time is 10 h. Note: The molar ratio of FeCl3·6H2O to UPy-(OH)2 in Example 3 is 1:1.

[0105] (3) After the complexation reaction is completed, slowly add polyetheramine D230 dropwise (dropwise rate 1.0 mL / min) for further chain extension. Raise the temperature of the oil bath to 50 °C, weigh polyetheramine D230 (25 mmol, 5.75 g), continue stirring in an oil bath at 50 °C and introduce nitrogen. The reaction time is 6 h until the chain extension reaction is complete. Note: The molar ratio of HDI to D230 is 4:1.

[0106] (4) After the reaction is completed, pour the mixed solution into a polytetrafluoroethylene mold, and carry out vacuum drying treatment at 85 °C for 72 h to remove the residual solvent. The sample is named Example 4 (SPUU-Fe / UPy).

[0107] Example 5

[0108] (1) It is consistent with Steps 1 to 3 of Example 1.

[0109] (2) After the above chain extension reaction is completed, lower the temperature to 40 °C, and then weigh the trivalent metal salt solid ferric chloride hexahydrate FeCl3·6H2O (50 mmol, 8.11 g, molecular weight 162.2 g / mol). At the same time, measure 20 mL of the organic solvent DMF, dissolve the solid FeCl3·6H2O in the solvent DMF, and perform ultrasonic treatment until completely dissolved. The solution is reddish-brown and add it to the reaction flask. Continue stirring in an oil bath at 50 °C and introduce nitrogen. The reaction time is 10 h. Note: The molar ratio of FeCl3·6H2O to UPy-(OH)2 in Example 5 is 2:1.

[0110] (3) After the complexation reaction is completed, polyetheramine D230 is slowly added dropwise (at a dropping rate of 1.0 mL / min) for further chain extension. The temperature of the oil bath is raised to 50 °C, and (25 mmol, 5.75 g) of polyetheramine D230 is weighed. It is continuously stirred in the oil bath at 50 °C, and nitrogen is introduced. The reaction time is 6 h until the chain extension reaction is completely finished. Note: The molar ratio of HDI to D230 is 4:1.

[0111] (4) After the reaction is completed, the mixed solution is poured into a polytetrafluoroethylene mold and vacuum-dried at 85 °C for 72 h to remove the residual solvent. The sample is named Example 5.

[0112] The infrared spectra of the samples prepared in Examples 1 to 5 are as Figure 1 shown,

[0113] As can be seen from the results, the stretching vibration peak at 1738 cm 1 in the figure belongs to the carbonyl group (-C=O-) in the urethane (-NHCOO-) group, and the characteristic peak at 1242 cm -1 is the stretching vibration peak of the -C-O- part in the urethane (-NHCOO-) group. In addition, with the incorporation of iron ions, the characteristic peak at 1738 cm -1 shows a red shift, indicating that the carbonyl group (-C=O-) in the urethane (-NHCOO-) group in this system has changed, that is, the addition of iron ions interferes with the formation of hydrogen bonds. It is worth noting that there is no vibration peak corresponding to -NCO at 2260 to 2280 cm -1 , indicating the complete reaction of the diisocyanate and the successful preparation of poly(urea-urethane).

[0114] Stress-strain curve tests were carried out on all samples of Examples 1 to 5, and the obtained results are shown in Figure 2 . The results are summarized in Table 1. Test standard: GB / T 1040-2006, test speed: 100 mm / min, test environment: 25 °C, toughness of the material: the area under the stress-strain curve, that is, the energy absorbed by the material per unit volume before fracture. From Figure 2 and the results in Table 1, it can be seen that the tensile strength of Example 1 is 16.9 MPa, the fracture strain is 1268%, and the toughness value is 121.3 MJ / m 3 . Therefore, through reasonable molecular design and regulation of the distribution of hard and soft segments, the materials of the examples all exhibit extraordinary mechanical properties, namely high mechanical strength, high stretchability and high toughness. Further, after introducing the Fe 3+After the coordination interaction formed by the -N- atom on the ureidopyrimidinone UPy unit, the mechanical properties of the material changed. That is, after incorporating different amounts of FeCl3, the mechanical property results were different, which confirmed that reasonably adjusting the ratio of the metal ligand (ureidopyrimidinone UPy unit) to the metal iron ion (Fe 3+ ) is crucial for the mechanical properties of the material. Among them, Example 2 exhibited ultra-high stretchability, outstanding tensile strength, and excellent toughness. Its maximum tensile strength was 36.1 MPa, the fracture strain was 1246%, and the toughness value was 205.5 MJ / m 3 . Example 4 exhibited a maximum fracture elongation of 1650%. This is because after adding an appropriate amount of FeCl3, the synergistic effect of metal coordination bonds and quadruple hydrogen bonds can effectively limit the mobility of the mobile phase and lead to continuous energy dissipation, that is, "phase-locked toughening" is achieved, so the fracture elongation of the material increases.

[0115] Generally speaking, Examples 1 to 5 all exhibited excellent mechanical properties, which was mainly due to the existence of dual physical crosslinking points in the polyurethane network structure. The dual physical crosslinking points mainly refer to quadruple hydrogen bonds and metal coordination bonds. In particular, the quadruple hydrogen bonds are hydrogen bond interactions formed by the self-assembly of ureidopyrimidinone units on the UPy-(OH)2 chain extender, while the metal coordination bonds are coordination interactions formed by the Fe 3+ in FeCl3 and the -N- atom on the ureidopyrimidinone UPy unit. Here, the reversibility of the dual physical crosslinking endows the polyurethane with a dynamic crosslinked network structure, which is conducive to achieving high energy dissipation under external force loading. Due to effective energy dissipation, non-covalent poly(urea-carbamate) exhibits a significant mechanical toughening effect under external force.

[0116] Table 1 Fracture elongation, ultimate tensile strength, and toughness of Examples 1 to 5

[0117] Serial number Strength (MPa) Elongation at break (%) <![CDATA[Toughness (MJ / m 3 )]]> Example 1 16.9 1268 121.3 Example 2 36.1 1246 205.5 Example 3 9.8 1377 75.5 Example 4 20.9 1650 170.0 Example 5 16.1 566 50.9

[0118] To analyze the strengthening and toughening mechanism of the polyurethane material prepared by the present invention, mechanical property tests were carried out at different tensile rates. The stress-strain curves of the sample in Example 4 at different tensile rates are shown in Figure 3 , test standard: GB / T 1040-2006, test speed: 10 mm / min to 200 mm / min, test environment: 25°C. The summary of mechanical properties at different tensile rates is shown in Table 2. The toughness of the material: the area under the stress-strain curve, that is, the energy absorbed by the material per unit volume before fracture. From Figure 3As can be seen from Table 2, at different stretching rates, Example 4 exhibits significantly different mechanical properties and shows an obvious rate dependence. Therefore, the stretching behavior of Example 4 related to the deformation rate further confirms the kinetic characteristics of the polymer chains. That is, Sample Example 4 shows an obvious rate dependence, presenting regular changes. As the deformation rate increases from 10 mm / min to 200 mm / min in sequence, its corresponding tensile strength increases in sequence, while the elongation at break shows a decreasing trend in sequence. In other words, the greater the stretching rate, the greater the tensile strength of the material, and the elongation at break decreases conversely.

[0119] The results show that at low strains (10 mm / min and 20 mm / min), the material exhibits low tensile strength and high elongation at break. At high strains (50 mm / min, 100 mm / min, and 200 mm / min), the tensile strength of the material increases significantly and the elongation at break decreases. The rate-dependent behavior exhibited by the material is mainly due to the presence of dual physical cross-linking points in the poly(ureaurethane) network structure. The dual physical cross-linking points mainly refer to quadruple hydrogen bonds and metal coordination bonds (the quadruple hydrogen bonds are brought by the first chain extender, and the metal coordination bonds are brought by the first chain extender and the metal salt solid, and they complex to form metal coordination bonds).

[0120] Table 2 Elongation at break, ultimate tensile strength, and toughness of Example 4

[0121] Tensile rate Strength (MPa) Elongation at break (%) <![CDATA[Toughness (MJ / m 3 )]]> 10 mm / min 17.0 1800 161.0 20 mm / min 18.1 1741 161.1 50 mm / min 19.8 1698 167.8 100 mm / min 20.9 1650 170.0 200 mm / min 21.5 1565 163.6

[0122] Since both the quadruple hydrogen bonds and the metal coordination bonds belong to supramolecular bonds, which are two kinds of non-covalent interactions between molecules, this non-covalent interaction will lead to reversible physical cross-linking without the formation of new chemical bonds, and the reversibility and reconstruction of supramolecular bonds can be realized.

[0123] The deformation rate is closely related to the breakage and reconstruction of the quadruple hydrogen bonds and the metal coordination bonds. At high strains, the reversible multiple hydrogen bonds are difficult to achieve rapid assembly, and energy dissipation is inhibited. Therefore, the elongation at break decreases, but its mechanical strength will increase. On the contrary, at low strains, the lower stretching rate provides opportunities for the breakage and reconstruction of multiple hydrogen bonds in the polymer chains, which helps to achieve effective and sufficient energy dissipation, thereby endowing the material with a high elongation at break, effectively regulating the mechanical properties of poly(ureaurethane), and showing significant mechanical enhancement and toughening effects under external forces.

[0124] The thermal stability performance of Example 4 was tested. Test atmosphere: nitrogen, test temperature range: room temperature to 700 °C. The thermogravimetric curve of Example 4 is shown in Figure 4 , from Figure 4It can be seen that taking Example 1 as an example, all samples showed excellent heat resistance. The SPUU-Fe / UPy sample, that is, Example 4 showed two decomposition temperature ranges: the hard segment decomposed at 250-350 °C, and the soft segment decomposed at 375-500 °C. The thermal weight loss temperature (T d , the temperature corresponding to 5% weight loss of the sample) was about 247 °C, which was better than most polyurethane elastomers and showed good stability. Therefore, the thermogravimetric analysis (TGA) results fully demonstrated that the poly(urea-carbamate) elastomer prepared by the present invention not only showed high strength, high toughness and high stretchability, but also had excellent heat resistance, and was expected to be applied in extreme conditions or complex environments.

[0125] To illustrate the uniform distribution of hard and soft segments in the polyurethane material, the microphase separation structure of SPUU-Fe / UPy prepared in Example 4 was studied by atomic force microscopy (AFM). Figure 6 Figure of atomic force microscopy (AFM) of SPUU-Fe / UPy, from Figure 6 As can be seen from the AFM results shown, SPUU-Fe / UPy presented obvious dark and bright regions, indicating that SPUU-Fe / UPy had a clear microphase separation structure. Among them, the dark region corresponded to the aggregation of the PCDL soft domain, and the bright region was attributed to the aggregation of hard domains (such as: multiple hydrogen bonds (UPy, ureido, carbamate groups), metal coordination bonds (Fe-UPy)).

[0126] Comparative Example 1

[0127] (1) It was consistent with Step 1 of Example 1.

[0128] (2) The amount of HDI in Step 2 of Example 1 was adjusted, and the molar ratio of HDI to PCDL-2000 was 2.5:1. That is, after the temperature of the oil bath was cooled to 80 °C, (125 mmol, 21.03 g) of hexamethylene diisocyanate (HDI, 168.2 g / mol) was weighed, and at the same time, 150 mL of N,N-dimethylformamide (DMF) was measured as a solvent. After the two were mixed evenly, they were added to a three-necked flask, and then 0.05 g of catalyst DBTDL was added dropwise. This step was a prepolymerization reaction, which was heated and stirred in an oil bath at 80 °C and nitrogen was introduced, and the reaction time was 4 h. Then about 10 mL of DMF was added to appropriately control the viscosity of the reactants to prevent gelation, and a polyurethane prepolymer was obtained.

[0129] (3) Adjust the amount of the first chain extender in Step 3 of Example 1, and the molar ratio of HDI to UPy-(OH)2 is 3.33:1. That is, after the prepolymer is prepared, the temperature remains unchanged. Weigh 37.5 mmol, 14.9 g of UPy-(OH)2, measure 150 mL of DMF, and ultrasonically treat until completely dissolved to obtain a milky white solution, which is then dropped into a three-necked flask. Continue stirring in an oil bath at 80 °C and introduce nitrogen for 5 h.

[0130] (4) Adjust the amount of the second chain extender in Step 4 of Example 1, and the molar ratio of HDI to D230 is 3.33:1. Adjust the temperature of the oil bath to 50 °C. After the temperature cools to 50 °C, weigh (37.5 mmol, 8.63 g) of polyetheramine D230, continue stirring in an oil bath at 50 °C, and introduce nitrogen. The reaction time is 6 h until it completely participates in the reaction.

[0131] (5) After the reaction ends, pour the solution into a polytetrafluoroethylene mold, and perform vacuum and drying treatment at 85 °C for 72 h to remove the residual solvent. The sample is named Comparative Example 1.

[0132] Comparative Example 2

[0133] (1) The same as Step 1 of Example 1.

[0134] (2) Adjust the amount of HDI in Step 2 of Example 1, and the molar ratio of HDI to PCDL-2000 is 3:1. That is, after the temperature of the oil bath cools to 80 °C, weigh (150 mmol, 25.23 g) of hexamethylene diisocyanate (HDI, 168.2 g / mol), and at the same time measure 150 mL of N,N-dimethylformamide (DMF) as the solvent. After mixing the two evenly, add them to a three-necked flask, and then drop 0.05 g of the catalyst DBTDL. This step is a prepolymerization reaction. Heat and stir in an oil bath at 80 °C and introduce nitrogen. The reaction time is 4 h. Then add about 20 mL of DMF to appropriately control the viscosity of the reactants to prevent gelation and obtain a polyurethane prepolymer.

[0135] (3) Adjust the amount of the first chain extender in Step 3 of Example 1, and the molar ratio of HDI to UPy-(OH)2 is 3:1. That is, after the prepolymer is prepared, the temperature remains unchanged. Weigh 50 mmol, 19.9 g of UPy-(OH)2, measure 150 mL of DMF, and ultrasonically treat until completely dissolved to obtain a milky white solution, which is then dropped into a three-necked flask. Continue stirring in an oil bath at 80 °C and introduce nitrogen for 5 h.

[0136] (4) Adjust the amount of the second chain extender in Step 4 of Example 1, and the molar ratio of HDI to D230 is 3:1. Adjust the temperature of the oil bath to 50 °C. After the temperature cools to 50 °C, weigh (50 mmol, 11.5 g) of polyetheramine D230, continue stirring in the oil bath at 50 °C, and introduce nitrogen. The reaction time is 6 h until the reaction is completely involved.

[0137] After the reaction is completed, pour the solution into a polytetrafluoroethylene mold, and carry out vacuum drying treatment at 85 °C for 72 h to remove the residual solvent. The sample is named Comparative Example 2.

[0138] Take Comparative Example 1 and Comparative Example 2 as the comparative examples of Example 1. By changing the ratio of isocyanate to polyol, reasonably adjust the ratio of the soft segment and the hard segment, and then evaluate the mechanical properties to demonstrate the superiority and advancement of the method of the present invention.

[0139] The stress-strain curves of Example 1 and Comparative Examples 1-2 at the same tensile rate are shown in Figure 5 , test standard: GB / T 1040-2006, test speed: 100 mm / min, test environment: 25 °C. The summary of the mechanical properties of Example 1 and Comparative Examples 1-2 at the same tensile rate is shown in Table 3. Through comparison, it is found that the mechanical properties of Comparative Example 1 and Comparative Example 2 are far lower than the results of Example 1. As described above, the strength, elongation at break and toughness of Comparative Example 1 are 11.9 MPa, 605% and 49.5 MJ / m 3 ; while the strength, elongation at break and toughness of Comparative Example 2 are 5.8 MPa, 728% and 29.2 MJ / m 3 . Compared with the example, when other ratios remain unchanged, in Comparative Example 1 and Comparative Example 2, due to the change of the contents of HDI, UPy-(OH)2 and D230, their mechanical properties decreased significantly, far lower than the samples of Example 1.

[0140] Table 3 Elongation at break, ultimate tensile strength and toughness of Example 1 and Comparative Examples 1-2

[0141] Serial number Strength (MPa) Elongation at break (%) <![CDATA[Toughness (MJ / m 3 )]]> Example 1 16.9 1268 121.3 Comparative example 1 11.9 605 49.5 Comparative example 2 5.8 728 29.2

[0142] Example 6

[0143] (1) Keep consistent with Steps 1-3 of Example 4.

[0144] (2) Replace the solid ferric chloride hexahydrate FeCl3·6H2O in step 4 of Example 4 with solid zinc chloride ZnCl2. The specific reaction is as follows. After the chain extension reaction is completed, lower the temperature to 50 °C. Then weigh 10 mmol, 1.36 g of ZnCl2 (molecular weight is 136.28 g / mol), and at the same time measure 14 mL of the solvent DMAc, keeping the concentration of the mixed solution at 0.1 g / mL. Dissolve the ZnCl2 solid in the solvent DMAc, and perform ultrasonic treatment until it is completely dissolved. Then add it dropwise to the reaction flask. The reaction conditions are stirring in an oil bath environment at a temperature of 50 °C and under a N2 atmosphere for 10 h.

[0145] (3) Then, slowly add dropwise (dropwise addition rate is 1 mL / min) 10 mmol, 2.3 g of polyetheramine D230, and continue stirring. The reaction is carried out at 50 °C and under a N2 atmosphere for 5 h.

[0146] (4) After the reaction is completed, pour the solution into a polytetrafluoroethylene mold and perform vacuum drying at 80 °C for 48 h to remove the residual solvent. The sample of Example 2 is named SPUU-Zn / UPy.

[0147] Example 7

[0148] (1) It is the same as steps 1-3 of Example 1.

[0149] (2) Replace the solid ferric chloride hexahydrate FeCl3·6H2O in step 4 of Example 1 with solid manganese chloride MnCl2. The specific reaction is as follows. After the chain extension reaction is completed, lower the temperature to 50 °C. Then weigh 10 mmol, 1.26 g of MnCl2 (molecular weight is 125.84 g / mol), and at the same time measure 13 mL of the solvent DMAc, keeping the concentration of the mixed solution at 0.1 g / mL. Dissolve the MnCl2 solid in the solvent DMAc, and perform ultrasonic treatment until it is completely dissolved. Then add it dropwise to the reaction flask. The reaction conditions are stirring in an oil bath environment at a temperature of 50 °C and under a N2 atmosphere for 10 h.

[0150] (3) Then, slowly add dropwise (dropwise addition rate is 1 mL / min) 10 mmol, 2.3 g of polyetheramine D230, and continue stirring. The reaction is carried out at 50 °C and under a N2 atmosphere for 5 h until the reaction is completed.

[0151] (4) After the reaction is completed, pour the solution into a polytetrafluoroethylene mold and perform vacuum drying at 80 °C for 48 h to remove the residual solvent. The sample of Example 3 is named SPUU-Mn / UPy.

[0152] Example 8

[0153] (1) It is the same as steps 1-3 of Example 4.

[0154] (2) Replace the solid ferric chloride hexahydrate FeCl3·6H2O in step 4 of Example 4 with solid copper chloride CuCl2. The specific reaction is as follows. After the chain extension reaction is completed, the temperature is lowered to 50 °C, and then 10 mmol, 1.34 g of CuCl2 (molecular weight is 134.45 g / mol) is weighed. At the same time, 14 mL of the solvent DMAc is measured, and the concentration of the mixed solution is kept at 0.1 g / mL. The solid CuCl2 is dissolved in the solvent DMAc, and ultrasonic treatment is carried out until it is completely dissolved, and then it is dropped into the reaction flask. The reaction conditions are stirring in an oil bath environment at a temperature of 50 °C and under a N2 atmosphere for 10 h.

[0155] (3) Then, 10 mmol, 2.3 g of polyetheramine D230 is slowly added dropwise, and stirring is continued. The reaction is carried out at 50 °C and under a N2 atmosphere for 5 h until the reaction is completed.

[0156] (4) After the reaction is completed, the solution is poured into a polytetrafluoroethylene mold and vacuum dried at 80 °C for 48 h to remove the residual solvent. The sample of Example 4 is named SPUU-Cu / UPy.

[0157] Mechanical properties

[0158] Stress-strain curve tests were carried out on all samples of Examples 4, 6 to 8, and the obtained results are shown in Figure 7 , and the results are summarized in Table 4. Test standard: GB / T 1040-2006, test speed: 100 mm / min, test environment: 25 °C. The toughness of the material is the area under the stress-strain curve, that is, the energy absorbed by the material per unit volume before fracture. From Figure 7 and the results in Table 4, it can be seen that the sample SPUU-Fe / UPy exhibits ultra-high stretchability, outstanding tensile strength and excellent toughness. Its maximum tensile strength is 20.9 MPa, the fracture strain is 1650%, and the toughness value is 170.0 MJ / m 3 . Therefore, through reasonable molecular design, the materials of the examples all exhibit extraordinary mechanical properties, namely high mechanical strength, high stretchability and high toughness. By changing the types of metal ions incorporated, significantly different mechanical properties are obtained. Among them, the mechanical properties of SPUU-Fe / UPy are the most excellent, followed by SPUU-Mn / UPy and SPUU-Cu / UPy, and the toughness value of SPUU-Zn / UPy is the lowest.

[0159] It can be seen that the polyurethane materials prepared by the preparation method provided by the present invention are rich in a large number of metal coordination bonds, providing an opportunity for the excellent toughness of the polyurethane materials. Specifically, Examples 1 to 4 all exhibit mechanical properties comparable to those of traditional polyurethanes, which is mainly due to the presence of sacrificial bonds in the polyurethane network structure.

[0160] Table 4 Elongation at break, ultimate tensile strength and toughness of Examples 4, 6 - 8

[0161] Serial number Strength (MPa) Elongation at break (%) <![CDATA[Toughness (MJ / m 3 )]]> SPUU-Fe / UPy 20.9 1650 170.0 SPUU-Zn / UPy 14.1 1107 93.2 SPUU-Mn / UPy 18.7 1128 123.9 SPUU-Cu / UPy 16.7 1070 106.9

[0162] To analyze the reinforcement and toughening mechanism of the polyurethane elastomer prepared by the present invention, mechanical property tests at different tensile rates were also carried out. The stress - strain curves of SPUU - Zn / UPy at different tensile rates are shown in Figure 8 , test standard: GB / T1040 - 2006, test speed: 10 mm / min and 100 mm / min, test environment: 25 °C. The summary of the mechanical properties of SPUU - Zn / UPy at different tensile rates is shown in Table 5. The toughness of the material: the area under the stress - strain curve, that is, the energy absorbed by the material per unit volume before fracture. From Figure 8 and the results in Table 5, it can be seen that at different tensile rates, SPUU - Zn / UPy shows significantly different mechanical properties and obvious rate dependence. Therefore, the tensile behavior of SPUU - Zn / UPy related to the deformation rate further confirms the kinetic characteristics of the polymer chains. That is, the sample SPUU - Zn / UPy shows obvious rate dependence and presents regular changes. As the deformation rate increases from 10 mm / min to 100 mm / min, its corresponding tensile strength increases significantly while the elongation at break decreases. The rate - dependent behavior exhibited by the material, showing different mechanical behaviors at different rates, is mainly due to the presence of metal coordination bonds in the polyurethane network structure and depends on the result of sacrificial bond action.

[0163] The deformation rate is closely related to the fracture and reconstruction of metal coordination bonds. At high strains, the dynamic reversible metal coordination bond action is difficult to achieve rapid reorganization, so the elongation at break decreases, but due to strain - induced orientation crystallization, its mechanical strength will increase. On the contrary, at low strains, the lower tensile rate provides more opportunities for the fracture and reconstruction of metal coordination bonds in the polymer chains, achieving greater energy dissipation, thus endowing the material with a high elongation at break and showing significant mechanical reinforcement and toughening effects under external forces.

[0164] Table 5 Elongation at break, ultimate tensile strength and toughness of SPUU - Zn / UPy

[0165] Tensile rate Strength (MPa) Elongation at break (%) <![CDATA[Toughness (MJ / m 3 )]]> 10 mm / min 12.1 1144 85.2 100 mm / min 14.1 1107 93.2

[0166] The above description is only a preferred embodiment of the present invention and does not impose any formal restrictions on the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can still be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a polyurethane material, characterized in that, It includes the following steps: Mix polyester polyol, diisocyanate, organic solvent and catalyst to carry out prepolymerization reaction to obtain a polyurethane prepolymer; Mix the polyurethane prepolymer with a first chain extender to carry out a first chain extension reaction to obtain a first chain extension product; the first chain extender is 2-urea-4[H]-pyrimidinone-2-amino-2-methyl-1,3-propanediol; Mix the first chain extension product, metal salt and organic solvent to carry out a complexation reaction to obtain a complex product; the metal salt is a trivalent metal salt, the molar ratio of the metal salt to the first chain extender is 3:1, and the metal element in the trivalent metal salt is Fe; Drop a second chain extender into the complex product to carry out a second chain extension reaction to obtain a second chain extension product; the second chain extender includes a small molecule diamine chain extender; Mold the second chain extension product to obtain the polyurethane material.

2. The preparation method according to claim 1, characterized in that, The molar ratio of the polyester polyol to the diisocyanate is 1:1 to 3.

3. The preparation method according to claim 1, wherein, The molar ratio of the diisocyanate to the first chain extender is 2 to 6:

1.

4. The preparation method according to claim 1, characterized in that, The temperature of the complexation reaction is 40 to 100 °C, and the time is 1 h to 15 h.

5. The preparation method according to claim 1, characterized in that, The small molecule diamine chain extender includes one or more of polyetheramine D230, adipic dihydrazide, terephthalic dihydrazide, 1,8-octanediamine, m-phenylenediamine, 4,4'-diaminodiphenylamine, 4,4'-dithiobis(diphenylamine) and o-xylenediamine.

6. The preparation method according to claim 1 or 5, characterized in that, The molar ratio of the diisocyanate to the second chain extender is 2 to 6:

1.

7. The polyurethane material prepared by the preparation method according to any one of claims 1 to 6.

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