High-toughness recoverable bio-based polyurethane and preparation method thereof

Abstract

The invention discloses high-toughness recoverable bio-based polyurethane and a preparation method thereof. The preparation method comprises the following steps: dissolving dithiol, methacrylic acid-2-(tert-butylamino) ethyl ester and a photoinitiator in a good solvent according to a certain molar ratio to prepare a precursor 1 containing di-tert-butylamino; the preparation method comprises the following steps: dissolving 2, 5-furandimethanol, oligomer polyol, a precursor 1, diisocyanate and a catalyst in a good solvent according to a certain molar ratio to prepare a linear polymer; the linear polymer and the maleimide modified cellulose are dissolved in a good solvent according to a certain mass ratio and then poured into a mold, and the high-toughness recoverable bio-based polyurethane is prepared after the solvent is volatilized. The bio-based polyurethane disclosed by the invention contains double dynamic covalent bonds and multiple dynamic non-covalent bonds, and the advantages of high toughness and recoverability of the bio-based polyurethane are realized through dynamic covalent-non-covalent interaction.

Description

Technical Field

[0001] The invention relates to a high-toughness recyclable bio-based polyurethane and a preparation method thereof, belonging to the technical field of polyurethane. Background Art

[0002] As the world's population grows, the global demand for energy, chemicals and polymer materials continues to increase. However, most chemicals and polymers come from fossil resources. As countries around the world are increasingly concerned about the depletion of fossil resources and environmental issues, researchers have begun to focus on the use of biomass resources to develop various chemicals and polymer materials. Among them, cellulose, as the world's most abundant biomass resource, has the advantages of a wide range of sources, renewable and degradable, and is one of the most promising alternative materials to fossil resources.

[0003] In recent years, polyurethane elastomer materials have been widely used in aerospace, electronic skin, soft robots and other fields due to their good chemical stability, easy structural control and excellent mechanical properties. Traditional polyurethane materials are difficult to recycle, resulting in serious waste of resources and environmental pollution. Therefore, the preparation of recyclable polyurethane is urgent for achieving sustainable green development. Generally, dynamic cross-linking strategy is an effective strategy for the preparation of recyclable polyurethane, but the strength of the dynamically cross-linked polymer network is weak, resulting in a serious decrease in its mechanical properties, limiting its practical application value.

[0004] Cellulose, as the world's most abundant natural biomass resource, has the advantages of being renewable, high-strength, and having multiple active hydroxyl groups. For centuries, it has been widely used in synthetic plastics, adhesives, coatings, and other fields. It can replace petroleum-based products to achieve green and sustainable development, showing broad application prospects. The multi-hydroxy structure enables maleimide to be easily introduced into the cellulose skeleton through chemical modification, achieving the controllable construction of maleimide-modified cellulose macromolecular crosslinkers, which can be used with linear polymers to prepare recyclable dynamic thermosetting polyurethanes through Diels-Alder reactions. Therefore, by preparing high-strength and recyclable bio-based thermosetting polyurethanes, it is possible to solve the problems of environmental pollution caused by the difficulty of reprocessing and recycling traditional polyurethane materials, which is of great significance to further expand the scope of application of cellulose and enhance the utilization value of cellulose. Summary of the invention

[0005] Purpose of the invention: In order to overcome the difficulty in recycling polyurethane and its poor mechanical properties, the present invention provides a high-strength and recyclable bio-based polyurethane.

[0006] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A high-strength and recyclable bio-based polyurethane, the general structural formula of which is as follows:

[0008]

[0009] Among them, R is a characteristic functional group of microcrystalline cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and carboxymethyl cellulose, which is H or any one of -CH3, -CH2CH3, -CH2COOH, -CH2CH2OH, and -CH2CH2CH2OH, R1 is a structural unit of diisocyanate, R2 is a structural unit of oligomer diol, and R3 is a structural unit of dithiol.

[0010] The present invention also provides a method for preparing high-toughness recyclable bio-based polyurethane, comprising the following steps:

[0011] Step 1, dissolving dithiol, 2-(tert-butylamino)ethyl methacrylate and a photoinitiator in a good solvent at a certain molar ratio and reacting at 25 to 40° C. under ultraviolet light for 6 to 10 hours to prepare a precursor 1;

[0012] Step 2, dissolving 2,5-furan dimethanol, oligomer polyol, precursor 1, diisocyanate, and catalyst in a good solvent at a certain molar ratio and reacting at 80-100° C. for 1-3 hours to prepare a linear polymer;

[0013] Step 3, dissolving the linear polymer and maleimide-modified cellulose in a good solvent according to a certain mass ratio and pouring the mixture into a mold, and reacting the mixture at 30-50° C. for 12-24 hours after the solvent evaporates to prepare a high-strength and recyclable bio-based polyurethane.

[0014] Preferably, the dithiol, 2-(tert-butylamino)ethyl methacrylate and the photoinitiator are in a certain molar ratio of dithiol: 2-(tert-butylamino)ethyl methacrylate: photoinitiator = 2:1:0.03-0.06.

[0015] Preferably: the dithiol is any one of 1,3-propanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,4-benzenedithiol, or a mixture of two or more thereof; the photoinitiator is any one of 2-hydroxy-2-methylpropiophenone and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, or a mixture of two or more thereof.

[0016] Preferably, the molar ratio of the 2,5-furan dimethanol, oligomer polyol, precursor 1, diisocyanate and catalyst is 2,5-furan dimethanol: oligomer polyol: precursor 1: diisocyanate: catalyst = 1: 0.8-1.2: 0.2-0.4: 1.8-2.2: 0.003-0.03.

[0017] Preferably, the oligomer polyol is any one of polytetramethylene glycol, polypropylene oxide glycol, polycaprolactone glycol and polycarbonate diol, or a mixture of two or more thereof.

[0018] Preferably, the diisocyanate is any one of toluene-2,4-diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and p-phenylene diisocyanate, or a mixture of two or more thereof.

[0019] Preferably: the catalyst is any one of stannous octoate, dibutyltin dilaurate, triethylenediamine, tetramethylbutylenediamine, triethylenediamine, tetramethylbutylenediamine, or a mixture of two or more thereof; the good solvent is any one of N,N-dimethylformamide, dimethyl sulfoxide, toluene, tetrahydrofuran, or a mixture of two or more thereof.

[0020] Preferably, the linear polymer and maleimide-modified cellulose are in a certain mass ratio of linear polymer:maleimide-modified cellulose=1:0.03-0.09.

[0021] Preferably, the maleimide-modified cellulose is any one of maleimide-modified methyl cellulose, maleimide-modified ethyl cellulose, maleimide-modified hydroxyethyl cellulose, maleimide-modified hydroxypropyl cellulose, maleimide-modified carboxymethyl cellulose, and maleimide-modified microcrystalline cellulose, or a mixture of two or more thereof.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The method for preparing high-strength and recyclable bio-based polyurethane of the present invention has the characteristics of simple preparation and good repeatability.

[0024] (2) The high-strength and recyclable bio-based polyurethane of the present invention can be used as a new type of bio-based polyurethane, which has excellent mechanical properties (strength up to 55.5MPa, toughness up to 144.25MJ / m 3 ) In addition, by introducing Diels–Alder bonds and hindered urea bonds and utilizing their properties of thermal dissociation and cooling recombination, the damaged network can be rearranged, thus achieving efficient reprocessing of bio-based polyurethane, which meets the requirements of the green development strategy and is suitable for a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the infrared spectrum of 2-(tert-butylamino)ethyl methacrylate and precursor 1 in Example 1.

[0026] Figure 2This is the uniaxial tensile stress-strain curve of the high-strength and recyclable bio-based polyurethane in Example 1 before and after recycling. DETAILED DESCRIPTION

[0027] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0028] The raw materials and reagents in the following examples are all commercially available.

[0029] Example 1

[0030] A method for preparing high-strength and recyclable bio-based polyurethane, in which ethyl cellulose is used to prepare high-strength and recyclable bio-based polyurethane, comprises the following steps:

[0031] In the first step, 1,6-hexanedithiol, 2-(tert-butylamino)ethyl methacrylate, and 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran at a molar ratio of [1,6-hexanedithiol]: [2-(tert-butylamino)ethyl methacrylate: [2-hydroxy-2-methylpropiophenone] = 2:1:0.03 and reacted at 25°C for 9 hours to prepare precursor 1. The reaction process is as follows:

[0032]

[0033] In the second step, 2,5-furan dimethanol, polytetrahydrofuran diol, precursor 1, isophorone diisocyanate, and dibutyltin dilaurate are reacted at a molar ratio of [2,5-furan dimethanol]: [polytetrahydrofuran diol]: [precursor 1]: [isophorone diisocyanate]: [dibutyltin dilaurate] = 1:1:0.2:2.2:0.003 at 90°C for 3h to prepare a linear polymer. The reaction process is as follows:

[0034]

[0035] In the third step, the linear polymer and maleimide-modified ethyl cellulose are dissolved in tetrahydrofuran at a mass ratio of [linear polymer]: [maleimide-modified ethyl cellulose] = 1:0.09 and poured into a mold. After the solvent evaporates, the mixture is reacted at 40°C for 18 hours to prepare a high-strength and recyclable bio-based polyurethane. The reaction process is as follows:

[0036]

[0037] In addition, the preparation of precursor 1 is based on the thiol-ene click reaction, in which the carbon-carbon double bond reacts with the thiol group under light conditions and the action of an initiator; the linear polymer is based on isocyanate and can react with hydroxyl and amino groups under catalyst and heating conditions to form carbamate bonds and urea bonds; the preparation of bio-based polyurethane is based on the Diels-Alder reaction, in which the maleimide group and the furan group undergo a diene addition reaction, so that the maleimide-modified cellulose is cross-linked with the linear polymer to finally obtain the bio-based polyurethane.

[0038] Example 2

[0039] The difference between this embodiment and embodiment 1 is that:

[0040] In the first step, 1,6-hexanedithiol, 2-(tert-butylamino)ethyl methacrylate, and 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran at a molar ratio of [1,6-hexanedithiol]:[2-(tert-butylamino)ethyl methacrylate:[2-hydroxy-2-methylpropiophenone]=2:1:0.06, and reacted at 30°C for 10 hours to prepare precursor 1;

[0041] In the second step, 2,5-furan dimethanol, polytetrahydrofuran diol, precursor 1, isophorone diisocyanate, and dibutyltin dilaurate are reacted at a molar ratio of [2,5-furan dimethanol]:[polytetrahydrofuran diol]:[precursor 1]:[isophorone diisocyanate]:[dibutyltin dilaurate]=1:1.2:0.4:1.8:0.03 at 80°C for 2.5h to prepare a linear polymer.

[0042] In the third step, the linear polymer and maleimide-modified ethyl cellulose are dissolved in tetrahydrofuran at a mass ratio of [linear polymer]:[maleimide-modified ethyl cellulose]=1:0.03 and poured into a mold. After the solvent evaporates, the mixture is reacted at 30°C for 24 hours to prepare high-strength and recyclable bio-based polyurethane.

[0043] Example 3

[0044] The difference between this embodiment and embodiment 1 is that:

[0045] In the first step, 1,6-hexanedithiol, 2-(tert-butylamino)ethyl methacrylate, and 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran at a molar ratio of [1,6-hexanedithiol]:[2-(tert-butylamino)ethyl methacrylate:[2-hydroxy-2-methylpropiophenone]=2:1:0.04, and reacted at 40°C for 6 hours to prepare precursor 1;

[0046] In the second step, 2,5-furan dimethanol, polytetrahydrofuran diol, precursor 1, isophorone diisocyanate, and dibutyltin dilaurate are reacted at a molar ratio of [2,5-furan dimethanol]:[polytetrahydrofuran diol]:[precursor 1]:[isophorone diisocyanate]:[dibutyltin dilaurate]=1:0.8:0.2:2.0:0.01 at 100°C for 1 h to prepare a linear polymer.

[0047] In the third step, the linear polymer and maleimide-modified ethyl cellulose are dissolved in tetrahydrofuran at a mass ratio of [linear polymer]:[maleimide-modified ethyl cellulose]=1:0.06 and poured into a mold. After the solvent evaporates, the mixture is reacted at 50°C for 12 hours to prepare high-strength and recyclable bio-based polyurethane.

[0048] Example 4

[0049] This embodiment uses methyl cellulose to prepare high-strength and recyclable bio-based polyurethane, including the following steps:

[0050] In the first step, 1,3-propanedithiol, 2-(tert-butylamino)ethyl methacrylate, and 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran at a molar ratio of [1,3-propanedithiol]:[2-(tert-butylamino)ethyl methacrylate:[2-hydroxy-2-methylpropiophenone]=2:1:0.05, and reacted at 30°C for 8 hours to prepare precursor 1;

[0051] In the second step, 2,5-furan dimethanol, polycaprolactone diol, precursor 1, isophorone diisocyanate, and dibutyltin dilaurate are reacted at a molar ratio of [2,5-furan dimethanol]:[polycaprolactone diol]:[precursor 1]:[isophorone diisocyanate]:[dibutyltin dilaurate]=1:0.9:0.3:2.2:0.005 at 100°C for 2 hours to prepare a linear polymer.

[0052] In the third step, the linear polymer and maleimide-modified methyl cellulose are dissolved in tetrahydrofuran at a mass ratio of [linear polymer]:[maleimide-modified methyl cellulose]=1:0.08 and poured into a mold. After the solvent evaporates, the mixture is reacted at 30°C for 24 hours to prepare high-strength and recyclable bio-based polyurethane.

[0053] Example 5

[0054] This embodiment uses hydroxyethyl cellulose to prepare high-strength and recyclable bio-based polyurethane, including the following steps:

[0055] In the first step, 1,8-octanedithiol, 2-(tert-butylamino)ethyl methacrylate, and 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran at a molar ratio of [1,8-octanedithiol]:[2-(tert-butylamino)ethyl methacrylate:[2-hydroxy-2-methylpropiophenone]=2:1:0.03, and reacted at 40°C for 6 hours to prepare precursor 1;

[0056] In the second step, 2,5-furan dimethanol, polytetrahydrofuran diol, precursor 1, toluene-2,4-diisocyanate, and dibutyltin dilaurate are reacted at a molar ratio of [2,5-furan dimethanol]:[polytetrahydrofuran diol]:[precursor 1]:[toluene-2,4-diisocyanate]:[dibutyltin dilaurate]=1:0.9:0.2:2.1:0.003 at 90°C for 3 hours to prepare a linear polymer.

[0057] In the third step, the linear polymer and maleimide-modified hydroxyethyl cellulose are dissolved in tetrahydrofuran at a mass ratio of [linear polymer]:[maleimide-modified hydroxyethyl cellulose]=1:0.09 and poured into a mold. After the solvent evaporates, the mixture is reacted at 50°C for 12 hours to prepare a high-strength and recyclable bio-based polyurethane.

[0058] Example 6

[0059] This embodiment uses hydroxypropyl cellulose to prepare high-strength and recyclable bio-based polyurethane, including the following steps:

[0060] In the first step, 1,4-benzenedithiol, 2-(tert-butylamino)ethyl methacrylate, and 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran at a molar ratio of [1,4-benzenedithiol]:[2-(tert-butylamino)ethyl methacrylate:[2-hydroxy-2-methylpropiophenone]=2:1:0.06, and reacted at 25°C for 10 hours to prepare precursor 1;

[0061] In the second step, 2,5-furan dimethanol, polycarbonate diol, precursor 1, p-phenylene diisocyanate, and triethylene diamine are reacted at a molar ratio of [2,5-furan dimethanol]: [polycarbonate diol]: [precursor 1]: [p-phenylene diisocyanate]: [triethylene diamine] = 1:1:0.2:2.2:0.01 at 80°C for 2 hours to prepare a linear polymer.

[0062] In the third step, the linear polymer and maleimide-modified hydroxypropyl cellulose are dissolved in tetrahydrofuran at a mass ratio of [linear polymer]:[maleimide-modified hydroxypropyl cellulose]=1:0.06 and poured into a mold. After the solvent evaporates, the mixture is reacted at 30°C for 24 hours to prepare high-strength and recyclable bio-based polyurethane.

[0063] Example 7

[0064] This embodiment uses carboxymethyl cellulose to prepare high-strength and recyclable bio-based polyurethane, including the following steps:

[0065] In the first step, 1,6-hexanedithiol, 2-(tert-butylamino)ethyl methacrylate, and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide were dissolved in dimethyl sulfoxide at a molar ratio of [1,6-hexanedithiol]:[2-(tert-butylamino)ethyl methacrylate:[diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide]=2:1:0.05 and reacted at 40°C for 6 hours to prepare precursor 1;

[0066] In the second step, 2,5-furan dimethanol, polypropylene oxide diol, precursor 1, hexamethylene diisocyanate, and stannous octoate were reacted at a molar ratio of [2,5-furan dimethanol]:[polypropylene oxide diol]:[precursor 1]:[hexamethylene diisocyanate]:[stannous octoate]=1:1:0.2:2.2:0.003 at 80°C for 3 hours to prepare a linear polymer.

[0067] In the third step, the linear polymer and maleimide-modified carboxymethyl cellulose are dissolved in dimethyl sulfoxide at a mass ratio of [linear polymer]:[maleimide-modified carboxymethyl cellulose] = 1:0.09 and poured into a mold. After the solvent evaporates, the mixture is reacted at 40°C for 18 hours to prepare high-strength and recyclable bio-based polyurethane.

[0068] Example 8

[0069] This embodiment uses microcrystalline cellulose to prepare high-strength and recyclable bio-based polyurethane, including the following steps:

[0070] In the first step, 1,6-hexanedithiol, 2-(tert-butylamino)ethyl methacrylate, and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide were dissolved in N,N-dimethylformamide at a molar ratio of [1,6-hexanedithiol]:[2-(tert-butylamino)ethyl methacrylate:[diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide]=2:1:0.05 and reacted at 40°C for 6 hours to prepare precursor 1;

[0071] In the second step, 2,5-furan dimethanol, polycaprolactone diol, precursor 1, dicyclohexylmethane diisocyanate, and tetramethylbutanediamine were reacted at a molar ratio of [2,5-furan dimethanol]:[polycaprolactone diol]:[precursor 1]:[dicyclohexylmethane diisocyanate]:[tetramethylbutanediamine]=1:0.8:0.4:2.2:0.005 at 80°C for 3 hours to prepare a linear polymer.

[0072] In the third step, the linear polymer and maleimide-modified microcrystalline cellulose are dissolved in N,N-dimethylformamide at a mass ratio of [linear polymer]:[maleimide-modified microcrystalline cellulose]=1:0.08 and poured into a mold. After the solvent evaporates, the mixture is reacted at 30°C for 20 hours to prepare high-strength and recyclable bio-based polyurethane.

[0073] like Figure 1 As shown, it is the infrared spectrum of 2-(tert-butylamino)ethyl methacrylate and precursor 1 in Example 1. In the figure, 1637 cm -1 、745cm -1 They correspond to the disappearance of the carbon-carbon double bond absorption peak in 2-(tert-butylamino)ethyl methacrylate and the appearance of the carbon-sulfur bond absorption peak in precursor 1, respectively, indicating the successful preparation of precursor 1.

[0074] like Figure 2 As shown, it is the uniaxial tensile stress-strain curve of the high-strength and tough recyclable bio-based polyurethane in Example 1 before and after recycling. It can be seen from the figure that the bio-based polyurethane has excellent mechanical properties before and after recycling, and the recovery efficiency of mechanical toughness reaches 95.42%, indicating that the bio-based polyurethane has excellent recyclability.

[0075] Tests have shown that the high-strength and recyclable bio-based polyurethane prepared in Examples 1 to 8 above has high strength and toughness and can be recycled through reprocessing, thereby extending the service life of the bio-based polyurethane and expanding the application field of the bio-based polyurethane.

[0076] The bio-based polyurethane of the present invention contains two kinds of dynamic covalent bonds, namely hindered urea bonds and Diels-Alder bonds, and multiple dynamic hydrogen bonds. During the stretching process of the material, the weak hydrogen bonds among the multiple hydrogen bonds are first broken to dissipate energy. As the tensile strain increases, the strong hydrogen bonds are broken and continue to dissipate energy to achieve high strength and high toughness. When the material is recycled, the hydrogen bonds, hindered urea bonds, and Diels-Alder bonds are reorganized after being thermally dissociated, so that the bio-based polyurethane network is rearranged. Therefore, the interaction between dynamic covalent bonds and multiple hydrogen bonds makes the bio-based polyurethane have the advantages of high strength, toughness, and recyclability.

[0077] The high-strength and recyclable bio-based polyurethane of the present invention not only has excellent mechanical properties, but also has excellent reprocessability, thereby improving the actual utilization value of the polymer; at the same time, its preparation method is simple, rapid, and has good repeatability.

[0078] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-strength and recyclable bio-based polyurethane, characterized in that: Its general structure is as follows: Among them, R is a characteristic functional group of microcrystalline cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and carboxymethyl cellulose, which is H or any one of -CH3, -CH2CH3, -CH2COOH, -CH2CH2OH, and -CH2CH2CH2OH, R1 is a structural unit of diisocyanate, R2 is a structural unit of oligomer diol, and R3 is a structural unit of dithiol.

2. A method for preparing a high-strength and recyclable bio-based polyurethane as claimed in claim 1, characterized in that: The steps include: Step 1, dissolving dithiol, 2-(tert-butylamino)ethyl methacrylate and a photoinitiator in a good solvent at a certain molar ratio and reacting at 25 to 40° C. under ultraviolet light for 6 to 10 hours to prepare a precursor 1; Step 2, dissolving 2,5-furan dimethanol, oligomer polyol, precursor 1, diisocyanate, and catalyst in a good solvent at a certain molar ratio and reacting at 80-100° C. for 1-3 hours to prepare a linear polymer; Step 3, dissolving the linear polymer and maleimide-modified cellulose in a good solvent according to a certain mass ratio and pouring the mixture into a mold, and reacting the mixture at 30-50° C. for 12-24 hours after the solvent evaporates to prepare a high-strength and recyclable bio-based polyurethane.

3. The preparation method according to claim 2, characterized in that: The dithiol, 2-(tert-butylamino)ethyl methacrylate and the photoinitiator are in a certain molar ratio of dithiol: 2-(tert-butylamino)ethyl methacrylate: photoinitiator = 2:1:0.03-0.

06.

4. The preparation method according to claim 3, characterized in that: The dithiol is any one of 1,3-propanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, and 1,4-benzenedithiol, or a mixture of two or more thereof; the photoinitiator is any one of 2-hydroxy-2-methylpropiophenone and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, or a mixture of two or more thereof.

5. The preparation method according to claim 4, characterized in that: The 2,5-furan dimethanol, oligomer polyol, precursor 1, diisocyanate and catalyst are prepared in a certain molar ratio of 2,5-furan dimethanol: oligomer polyol: precursor 1: diisocyanate: catalyst = 1: 0.8-1.2: 0.2-0.4: 1.8-2.2: 0.003-0.

03.

6. The preparation method according to claim 5, characterized in that: The oligomer polyol is any one of polytetramethylene glycol, polypropylene oxide glycol, polycaprolactone glycol and polycarbonate glycol or a mixture of two or more thereof.

7. The preparation method according to claim 6, characterized in that: The diisocyanate is any one of toluene-2,4-diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and p-phenylene diisocyanate, or a mixture of two or more thereof.

8. The preparation method according to claim 7, characterized in that: The catalyst is any one of stannous octoate, dibutyltin dilaurate, triethylenediamine, tetramethylbutylene diamine, triethylenediamine, tetramethylbutylene diamine, or a mixture of two or more thereof; the good solvent is any one of N,N-dimethylformamide, dimethyl sulfoxide, toluene, and tetrahydrofuran, or a mixture of two or more thereof.

9. The preparation method according to claim 8, characterized in that: The linear polymer and maleimide modified cellulose are in a certain mass ratio of linear polymer: maleimide modified cellulose = 1: 0.03-0.

09.

10. The preparation method according to claim 9, characterized in that: The maleimide-modified cellulose is any one of maleimide-modified methyl cellulose, maleimide-modified ethyl cellulose, maleimide-modified hydroxyethyl cellulose, maleimide-modified hydroxypropyl cellulose, maleimide-modified carboxymethyl cellulose, and maleimide-modified microcrystalline cellulose, or a mixture of two or more thereof.

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