Bio-based polyurethane elastomers with high strength and high tensile ratio and methods of making the same

Abstract

The application relates to a kind of high-strength high tensile ratio polyurethane elastomer materials, and the composition raw materials include low molecular weight polyol 30-50 parts, diisocyanate 40-60 parts, chain extender 5-30 parts, catalyst 0.01-0.05 parts, to prepare a series of polyurethane elastomer materials.The polyurethane elastomer material provided by the application, long-chain soft segment, isocyanate unit, chain extender unit with adjustable high-density hydrogen bond synergistic effect, so that the elastomer material has excellent mechanical properties, high strength and high toughness, the tensile strength can reach 42.78Mpa, and the elongation at break can reach 1675.23%;The structure of chain extender can be flexibly controlled, the preparation method is simple to operate, suitable for large-scale continuous line production, has good implementation value and market prospect, greatly widens the application range of polyurethane elastomer material.

Description

Technical Field

[0001] This invention belongs to the field of bio-based polyurethane elastomer technology, specifically relating to a class of high-strength, high-strength bio-based polyurethane elastomers and their preparation methods. Background Technology

[0002] Polyurethane, also known as the "fifth largest plastic," boasts excellent mechanical properties and good aging resistance, making it widely used in home decoration, aviation, aerospace, automobile manufacturing, and liquefied natural gas transport vehicles (ships). However, the polyurethane industry currently relies heavily on petroleum resource extraction for its raw materials. With the increasing depletion of non-renewable petroleum resources and the growing demand for sustainable development across the chemical industry, it is imperative to actively explore and develop environmentally friendly polyurethane materials.

[0003] The two most important performance indicators for evaluating polyurethane materials are strength and toughness, and practical applications often require both. The performance of polyurethane materials depends on their condensed-state structure, particularly the unique separation of soft and hard microphases within their molecular structure. Hydrogen bonds, a prevalent intermolecular force in polyurethane materials, are the driving force behind this microphase separation. In recent years, there has been widespread interest in enhancing the performance of polyurethane materials by introducing hydrogen bonding interactions. However, simply increasing the hydrogen bond density often leads to hard segment accumulation, causing stress concentration and ultimately reducing material performance. Therefore, optimizing the strength and distribution of hydrogen bonds within polyurethane materials is the most effective way to improve their mechanical properties.

[0004] Patent application CN 201811506170.1 discloses a high-mechanical-performance polysiloxane-polyether type polyurethane elastomer and its preparation method. This patent synthesizes two prepolymers separately, then mixes them for chain extension copolymerization to obtain a high-strength polyurethane elastomer. Patent application CN202110047448.9 discloses a high-strength, wear-resistant thermoplastic polyurethane elastomer and its preparation method. By forming a polymer / nanocomposite structure, it effectively improves the mechanical properties of the thermoplastic polyurethane elastomer, increasing its strength and wear resistance, thereby effectively improving its tensile strength and other mechanical properties. Although the above-mentioned existing solutions have made considerable contributions to improving the mechanical properties of polyurethane elastomers, they still suffer from problems such as not being able to simultaneously achieve high strength and high tensile ratio, complex processes, and almost complete reliance on petroleum resources. Therefore, developing a class of high-strength, high-tensile-ratio, simple-process, and environmentally friendly bio-based polyurethane elastomers is an urgent technical problem to be solved. Summary of the Invention

[0005] To address the technical problems of existing polyurethane materials, such as their inability to simultaneously achieve high strength and high elongation ratio, complex processing, and near-complete reliance on petroleum resources, this invention provides a class of bio-based polyurethane elastomer materials that are high in strength and high in elongation ratio, have simple processing, and are sourced from environmentally friendly sources.

[0006] In a first aspect, the present invention provides a class of high-strength, high-tensile-ratio bio-based polyurethane elastomers, comprising the following raw material components in molar proportions:

[0007] 30-50 parts of low molecular weight polyols

[0008] 40-60 parts of diisocyanate,

[0009] Chain extender 5-30 parts,

[0010] Catalyst 0.01-0.05 parts.

[0011] Furthermore, the chain extender has the following structure:

[0012]

[0013] The R is selected from furanyl, phenyl, ...

[0014] Where n is a natural number, and its value ranges from 4 to 10.

[0015] Further, the diisocyanate includes at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate (MDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), lysine diisocyanate, 1,4-cyclohexane diisocyanate, and toluene diisocyanate (TDI).

[0016] Furthermore, the catalyst comprises at least one of dibutyltin dilaurate, stannous octanoate, stannous isooctanoate, phosphoric acid, oleic acid, adipic acid, and triethylamine, preferably dibutyltin dilaurate.

[0017] Further, the low molecular weight polyol includes at least one of polytetrahydrofuran ether diol, polycaprolactone diol, polyethylene glycol, polypropylene glycol, polyethylene adipate diol, polypropylene adipate diol, polybutylene adipate diol, polyethylene carbonate diol, polypropylene carbonate diol, and polybutylene carbonate diol.

[0018] Furthermore, the low molecular weight polyol has an average molecular weight of 600-3000.

[0019] Furthermore, the molar ratio of the low molecular weight polyol to the chain extender is (1-10):1.

[0020] Furthermore, the molar ratio of the low molecular weight polyol to the chain extender is (3-7):1.

[0021] Secondly, the present invention provides a method for preparing a class of high-strength, high-strength-ratio bio-based polyurethane elastomers, comprising the following steps:

[0022] S1. First, add low molecular weight polyol to the reactor and dehydrate it under vacuum heating;

[0023] Under the protection of an S2, inert gas flow, diisocyanate, catalyst, and a first solvent are added, and the reaction yields a prepolymer.

[0024] S3. Under the protection of an inert gas flow, a chain extender is added and mixed with a second solvent to carry out a chain extension reaction; then, after casting, curing, and drying, the high-strength, high-strength bio-based polyurethane elastomer is obtained.

[0025] Further, the first solvent in step S2 and the second solvent in step S3 are both selected from at least one of toluene, xylene, acetone, dichloromethane, chloroform, tetrahydrofuran, acetonitrile, ethyl acetate, butyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide or dimethyl sulfoxide, preferably N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

[0026] Furthermore, in step S2, the amount of the first solvent added is 3-10 times the amount of the diisocyanate substance;

[0027] The amount of the second solvent added in step S3 is 30-100 times the amount of the diisocyanate substance.

[0028] Furthermore, in step S1, the vacuum heating dehydration process has a vacuum degree of <200Pa, preferably within 80Pa; a heating temperature of 50-120℃, preferably 90-100℃; and a dehydration time of 1-5h, preferably 3-4h.

[0029] Furthermore, in step S2, during the prepolymer preparation process, the heating temperature is 50-80℃, preferably 60-70℃; the prepolymerization time is 2-5h, preferably 3-4h.

[0030] Further, in step S3, during the chain extension and curing stage, the chain extension reaction heating temperature is 40-80℃, preferably 50-60℃; the chain extension reaction time is 2-5h, preferably 3-4h; the curing temperature is 40-100℃, preferably 50-70℃; and the curing time is 24-72h, preferably 36-48h.

[0031] Beneficial effects:

[0032] (1) In the polyurethane elastomer material provided by the present invention, the long-chain soft segments, isocyanate units and chain extender units containing adjustable high-density hydrogen bonds work together to make the elastomer material have excellent mechanical properties, with both high strength and high toughness. The tensile strength can reach 42.78 MPa and the elongation at break can reach 1675.23%, which greatly broadens the application range of polyurethane elastomer materials.

[0033] (2) The polyurethane elastomer chain extender provided by this invention is green in origin and belongs to bio-based chain extender, which reduces the dependence of polyurethane materials on petroleum resources and brings us closer to the goal of sustainable development in the chemical industry.

[0034] (3) The polyurethane elastomer chain extender structure provided by the present invention can be flexibly controlled, and polyurethane elastomer materials required for different application scenarios can be prepared by adjusting the chain extender structure.

[0035] (4) The method for preparing high-strength, high-strength polyurethane elastomer materials provided by the present invention is simple to operate, suitable for large-scale continuous production, and has good implementation value and market prospects. Attached Figure Description

[0036] Figure 1 The above are the synthesis route diagrams for Examples 1-8. Detailed Implementation

[0037] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0038] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0039] The preferred embodiments of the present invention will now be described in detail with reference to specific examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and essence.

[0040] Test instrument model: The universal tensile testing machine used is model Instron5567A.

[0041] Example 1 (Preparation of polyurethane; chain extender: dihydrazide compound containing succinamide structure (n=4); molar ratio of low molecular weight diol to chain extender: 7:3)

[0042] (1) Preparation of the prepolymer: The reaction was carried out in a three-necked reaction flask equipped with a mechanical stirrer and nitrogen inlet and outlet. Polytetrahydrofuran ether diol (PTMG, weight average molecular weight 1000, 5.6 g, 0.0056 mol) was added to the reactor, the oil bath temperature was raised to 100℃, and the mixture was evacuated for 3 h (<100 Pa) to remove water. Then, isophorone diisocyanate (IPDI, 1.78 g, 0.008 mol), dibutyltin dilaurate (0.0074 g, 0.1% of the total mass of PTMG and IPDI) and 3 ml DMF were added, the temperature was lowered to 70℃, and the reaction was carried out for 4 h to obtain the prepolymer.

[0043] (2) Chain extension and curing: The bio-based chain extender, a dihydrazide compound containing a succinamide structure (0.76 g, 0.0024 mol), was dissolved in 50 mL of DMF and mixed thoroughly with the prepolymer. The reaction was continued at 50 °C for 3 h. The polymer solution was cast into uniform sheets 2-3 mm thick. The synthesized polymer was then dried in a 50 °C hot air circulating oven for 24 h, and further dried in a 50 °C vacuum oven for 24 h to remove the solvent. The synthesis route is shown below. Figure 1 As shown.

[0044] Example 2 (Preparation of polyurethane; chain extender: a dihydrazide compound containing an adipamide structure (n=6); molar ratio of low molecular weight diol to chain extender: 7:3)

[0045] (1) Preparation of the prepolymer: The reaction was carried out in a three-necked reaction flask equipped with a mechanical stirrer and nitrogen inlet and outlet. Polytetrahydrofuran ether diol (PTMG, weight average molecular weight 1000, 5.6 g, 0.0056 mol) was added to the reactor, the oil bath temperature was raised to 100℃, and the mixture was evacuated for 3 h (<100 Pa) to remove water. Then, isophorone diisocyanate (IPDI, 1.78 g, 0.008 mol), dibutyltin dilaurate (0.0074 g, 0.1% of the total mass of PTMG and IPDI) and 3 ml DMF were added, the temperature was lowered to 70℃, and the reaction was carried out for 4 h to obtain the prepolymer.

[0046] (2) Chain extension and curing: The bio-based chain extender, a dihydrazide compound containing an adipamide structure (0.83 g, 0.0024 mol), was dissolved in 50 mL of DMF and mixed thoroughly with the prepolymer. The reaction was continued at 50 °C for 3 h. The polymer solution was cast into uniform sheets 2-3 mm thick. The synthesized polymer was then dried in a 50 °C hot air circulating oven for 24 h, and further dried in a 50 °C vacuum oven for 24 h to remove the solvent. The synthesis route is shown below. Figure 1 As shown.

[0047] Example 3 (Preparation of polyurethane; chain extender: dihydrazide compound containing octadiamide structure (n=8); molar ratio of low molecular weight diol to chain extender: 7:3)

[0048] (1) Preparation of the prepolymer: The reaction was carried out in a three-necked reaction flask equipped with a mechanical stirrer and nitrogen inlet and outlet. Polytetrahydrofuran ether diol (PTMG, weight average molecular weight 1000, 5.6 g, 0.0056 mol) was added to the reactor, the oil bath temperature was raised to 100℃, and the mixture was evacuated for 3 h (<100 Pa) to remove water. Then, isophorone diisocyanate (IPDI, 1.78 g, 0.008 mol), dibutyltin dilaurate (0.0074 g, 0.1% of the total mass of PTMG and IPDI) and 3 ml DMF were added, the temperature was lowered to 70℃, and the reaction was carried out for 4 h to obtain the prepolymer.

[0049] (2) Chain extension and curing: The bio-based chain extender, a dihydrazide compound containing an octanoic acid diamide structure (0.89 g, 0.0024 mol), was dissolved in 50 mL of DMF and mixed thoroughly with the prepolymer. The reaction was continued at 50 °C for 3 h. The polymer solution was cast into uniform sheets 2-3 mm thick. The synthesized polymer was then dried in a 50 °C hot air circulating oven for 24 h, and further dried in a 50 °C vacuum oven for 24 h to remove the solvent. The synthesis route is shown below. Figure 1 As shown.

[0050] Example 4 (Preparation of polyurethane; chain extender: dihydrazide compound containing sebacamide structure (n=10); molar ratio of low molecular weight diol to chain extender: 7:3)

[0051] (1) Preparation of the prepolymer: The reaction was carried out in a three-necked reaction flask equipped with a mechanical stirrer and nitrogen inlet and outlet. Polytetrahydrofuran ether diol (PTMG, weight average molecular weight 1000, 5.6 g, 0.0056 mol) was added to the reactor, the oil bath temperature was raised to 100℃, and the mixture was evacuated for 3 h (<100 Pa) to remove water. Then, isophorone diisocyanate (IPDI, 1.78 g, 0.008 mol), dibutyltin dilaurate (0.0074 g, 0.1% of the total mass of PTMG and IPDI) and 3 ml DMF were added, the temperature was lowered to 70℃, and the reaction was carried out for 4 h to obtain the prepolymer.

[0052] (2) Chain extension and curing: The bio-based chain extender, a dihydrazide compound containing a sebacamide structure (0.96 g, 0.0024 mol), was dissolved in 50 mL of DMF and mixed thoroughly with the prepolymer. The reaction was continued at 50 °C for 3 h. The polymer solution was cast into uniform sheets 2-3 mm thick. The synthesized polymer was then dried in a 50 °C hot air circulating oven for 24 h, and further dried in a 50 °C vacuum oven for 24 h to remove the solvent. The synthesis route is shown below. Figure 1 As shown.

[0053] Example 5 (Preparation of polyurethane; chain extender: a dihydrazide compound containing a furan dicarboxamide structure (R = 2,5-substituted furanyl); molar ratio of low molecular weight diol to chain extender: 7:3)

[0054] (1) Preparation of the prepolymer: The reaction was carried out in a three-necked reaction flask equipped with a mechanical stirrer and nitrogen inlet and outlet. Polytetrahydrofuran ether diol (PTMG, weight average molecular weight 1000, 5.6 g, 0.0056 mol) was added to the reactor, the oil bath temperature was raised to 100℃, and the mixture was evacuated for 3 h (<100 Pa) to remove water. Then, isophorone diisocyanate (IPDI, 1.78 g, 0.008 mol), dibutyltin dilaurate (0.0074 g, 0.1% of the total mass of PTMG and IPDI) and 3 ml DMF were added, the temperature was lowered to 70℃, and the reaction was carried out for 4 h to obtain the prepolymer.

[0055] (2) Chain extension and curing: The bio-based chain extender, a dihydrazide compound containing a furanyl dicarboxamide structure (0.85 g, 0.0024 mol), was dissolved in 50 mL of DMF and mixed thoroughly with the prepolymer. The reaction was continued at 50 °C for 3 h. The polymer solution was cast into uniform sheets 2-3 mm thick. The synthesized polymer was then dried in a 50 °C hot air circulating oven for 24 h, and further dried in a 50 °C vacuum oven for 24 h to remove the solvent. The synthesis route is shown below. Figure 1 As shown.

[0056] Example 6 (Preparation of polyurethane; chain extender: dihydrazide compound containing terephthalamide structure (R = 1,4-substituted phenyl); molar ratio of low molecular weight diol to chain extender: 7:3)

[0057] (1) Preparation of the prepolymer: The reaction was carried out in a three-necked reaction flask equipped with a mechanical stirrer and nitrogen inlet and outlet. Polytetrahydrofuran ether diol (PTMG, weight average molecular weight 1000, 5.6 g, 0.0056 mol) was added to the reactor, the oil bath temperature was raised to 100℃, and the mixture was evacuated for 3 h (<100 Pa) to remove water. Then, isophorone diisocyanate (IPDI, 1.78 g, 0.008 mol), dibutyltin dilaurate (0.0074 g, 0.1% of the total mass of PTMG and IPDI) and 3 ml DMF were added, the temperature was lowered to 70℃, and the reaction was carried out for 4 h to obtain the prepolymer.

[0058] (2) Chain extension and curing: The bio-based chain extender, a dihydrazide compound containing a terephthalamide structure (0.88 g, 0.0024 mol), was dissolved in 50 mL of DMF and mixed thoroughly with the prepolymer. The reaction was continued at 50 °C for 3 h. The polymer solution was cast into uniform sheets 2-3 mm thick. The synthesized polymer was then dried in a 50 °C hot air circulating oven for 24 h, and further dried in a 50 °C vacuum oven for 24 h to remove the solvent. The synthesis route is shown below. Figure 1 As shown.

[0059] Example 7 (Preparation of polyurethane; chain extender: a dihydrazide compound containing isoflurone diurea group (R = 1-substituted-3-(substituted methyl)-3,5,5-trimethylcyclohexyl); molar ratio of low molecular weight diol to chain extender: 7:3)

[0060] (1) Preparation of the prepolymer: The reaction was carried out in a three-necked reaction flask equipped with a mechanical stirrer and nitrogen inlet and outlet. Polytetrahydrofuran ether diol (PTMG, weight average molecular weight 1000, 5.6 g, 0.0056 mol) was added to the reactor, the oil bath temperature was raised to 100℃, and the mixture was evacuated for 3 h (<100 Pa) to remove water. Then, isophorone diisocyanate (IPDI, 1.78 g, 0.008 mol), dibutyltin dilaurate (0.0074 g, 0.1% of the total mass of PTMG and IPDI) and 3 ml DMF were added, the temperature was lowered to 70℃, and the reaction was carried out for 4 h to obtain the prepolymer.

[0061] (2) Chain extension and curing: The bio-based chain extender, a dihydrazide compound containing an isoflurane diurea group (1.10 g, 0.0024 mol), was dissolved in 50 mL of DMF and mixed thoroughly with the prepolymer. The reaction was continued at 50 °C for 3 h. The polymer solution was cast into uniform sheets 2-3 mm thick. The synthesized polymer was then dried in a 50 °C hot air circulating oven for 24 h, and further dried in a 50 °C vacuum oven for 24 h to remove the solvent. The synthesis route is shown below. Figure 1 As shown.

[0062] Example 8 (Preparation of polyurethane; chain extender: a dihydrazide compound containing isoflurane diurea group (R = 1-substituted-3-(substituted methyl)-3,5,5-trimethylcyclohexyl); molar ratio of low molecular weight diol to chain extender: 5:5)

[0063] (1) Preparation of the prepolymer: The reaction was carried out in a three-necked reaction flask equipped with a mechanical stirrer and nitrogen inlet and outlet. Polytetrahydrofuran ether diol (PTMG, weight average molecular weight 1000, 4 g, 0.004 mol) was added to the reactor, the oil bath temperature was raised to 100℃, and the mixture was evacuated for 3 h (<100 Pa) to remove water. Then, isophorone diisocyanate (IPDI, 1.78 g, 0.008 mol), dibutyltin dilaurate (0.0074 g, 0.1% of the total mass of PTMG and IPDI) and 3 ml DMF were added, the temperature was lowered to 70℃, and the reaction was carried out for 4 h to obtain the prepolymer.

[0064] (2) Chain extension and curing: The bio-based chain extender, a dihydrazide compound containing an isoflurane diurea group (1.83 g, 0.004 mol), was dissolved in 50 mL of DMF and mixed thoroughly with the prepolymer. The reaction was continued at 50 °C for 3 h. The polymer solution was cast into uniform sheets 2-3 mm thick. The synthesized polymer was then dried in a 50 °C hot air circulating oven for 24 h, and further dried in a 50 °C vacuum oven for 24 h to remove the solvent. The synthesis route is shown below. Figure 1 As shown.

[0065] Comparative Example 1 (Preparation of polyurethane; chain extender: adipic acid dihydrazide; molar ratio of low molecular weight diol to chain extender: 7:3)

[0066] (1) Preparation of the prepolymer: The reaction was carried out in a three-necked reaction flask equipped with a mechanical stirrer and nitrogen inlet and outlet. Polytetrahydrofuran ether diol (PTMG, weight average molecular weight 1000, 5.6 g, 0.0056 mol) was added to the reactor, the oil bath temperature was raised to 100℃, and the mixture was evacuated for 3 h (<100 Pa) to remove water. Then, isophorone diisocyanate (IPDI, 1.78 g, 0.008 mol), dibutyltin dilaurate (0.0074 g, 0.1% of the total mass of PTMG and IPDI) and 3 ml DMF were added, the temperature was lowered to 70℃, and the reaction was carried out for 4 h to obtain the prepolymer.

[0067] (2) Chain extension and curing: The chain extender, adipic acid dihydrazide (0.42 g, 0.0024 mol), was dissolved in 50 mL of DMF and mixed evenly with the prepolymer. The reaction was continued at 50 °C for 3 h. The polymer solution was cast into uniform sheets with a thickness of 2-3 mm. The synthesized polymer was then placed in a hot air circulating oven at 50 °C for 24 h and dried in a vacuum oven at 50 °C for another 24 h to further remove the solvent.

[0068] The mechanical properties of the polyurethane elastomers prepared in Examples 1-9 and Comparative Example 1 were tested, and the results are shown in the table below.

[0069]

[0070]

[0071] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A high-strength, high-tensile-ratio bio-based polyurethane elastomer, characterized in that, The raw material components are comprised in molar amounts as follows: 30-50 parts of low molecular weight polyols 40-60 parts of diisocyanate, Chain extender 5-30 parts, Catalyst 0.01-0.05 parts; The low molecular weight polyols have an average molecular weight of 600-3000. The chain extender has the following structure: ； The R is selected from furanyl, phenyl, ... , , ; Where n is a natural number, and its value ranges from 4 to 10.

2. The high-strength, high-tensile-ratio bio-based polyurethane elastomer according to claim 1, characterized in that, The diisocyanate includes hexamethylene diisocyanate, diphenylmethane diisocyanate (MDI), and 4,4'-diisocyanate. Dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), lysine diisocyanate, 1,4 At least one of cyclohexane diisocyanate and toluene diisocyanate (TDI).

3. The high-strength, high-tensile-ratio bio-based polyurethane elastomer according to claim 1, characterized in that, The catalyst includes at least one of dibutyltin dilaurate, stannous octoate, stannous isooctanoate, and triethylamine.

4. The high-strength, high-tensile-ratio bio-based polyurethane elastomer according to claim 1, characterized in that, The low molecular weight polyols include at least one of polytetrahydrofuran ether diol, polycaprolactone diol, polyethylene glycol, polypropylene glycol, polyethylene adipate diol, polypropylene adipate diol, polybutylene adipate diol, polyethylene carbonate diol, polypropylene carbonate diol, and polybutylene carbonate diol.

5. The high-strength, high-tensile-ratio bio-based polyurethane elastomer according to claim 1, characterized in that, The molar ratio of the low molecular weight polyol to the chain extender is (3-7):

1.

6. A method for preparing a high-strength, high-tensile-ratio bio-based polyurethane elastomer as described in any one of claims 1-5, characterized in that: S1. First, add low molecular weight polyol to the reactor and dehydrate it under vacuum heating; Under the protection of S2 and inert gas flow, diisocyanate, catalyst and first solvent are added to the reactor to react and obtain prepolymer; S3. Under the protection of an inert gas flow, a chain extender and a second solvent are added, mixed, and heated to 40-80℃ for chain extension reaction for 2-5 hours. After casting, curing, and drying, the high-strength, high-strength bio-based polyurethane elastomer is obtained.

7. The preparation method according to claim 6, characterized in that, The first solvent and the second solvent are both selected from at least one of toluene, xylene, acetone, dichloromethane, chloroform, tetrahydrofuran, acetonitrile, ethyl acetate, butyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, or dimethyl sulfoxide.

8. The preparation method according to claim 6, characterized in that: In step S1, during the vacuum heating and dehydration process, the vacuum degree of the reactor is <200Pa, the heating temperature is 50-120℃, and the dehydration time is 1-5h.

9. The preparation method according to claim 6, characterized in that: In step S2, the heating temperature is 50-80℃ and the prepolymerization time is 2-5h.

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