High toughness recyclable bio-based polyurethane and method of making same

Abstract

The application discloses a kind of high tough recyclable bio-based polyurethane and preparation method thereof, dithiol, methyl methacrylate-2-(tert-butyl amino) ethyl ester, photoinitiator are dissolved in good solvent preparation containing double tert-butyl amino precursor 1 according to certain molar ratio;2,5-furan dimethyl alcohol, oligomer polyol, precursor 1, diisocyanate, catalyst are dissolved in good solvent preparation linear polymer according to certain molar ratio;Linear polymer, maleimide modified cellulose are dissolved in good solvent after certain mass ratio is poured into mould, and high tough recyclable bio-based polyurethane is prepared after solvent volatilization.The bio-based polyurethane disclosed in the application contains double dynamic covalent bond and multiple dynamic non-covalent bond, and dynamic covalent-non-covalent interaction realizes the advantages of high tough recyclable bio-based polyurethane.

Description

TECHNICAL FIELD

[0001] The application relates to a high-toughness recyclable bio-based polyurethane and a preparation method thereof, and belongs to the technical field of polyurethane. BACKGROUND

[0002] With the growth of the world population, the global demand for energy, chemicals and high molecular materials is increasing. However, most chemicals and high molecules are derived from fossil resources. As the world's fossil resources are decreasing and the environmental problems are increasingly valued, researchers have focused on developing various chemicals and polymer materials by using biomass resources. Among them, cellulose, as the most abundant biomass resource in the world, has the advantages of wide source, renewability, biodegradability and the like, and is one of the most potential fossil resource replacement materials.

[0003] In recent years, polyurethane elastomer materials are widely used in the fields of aerospace, electronic skin and soft robot due to their good chemical stability, easy-to-control structure and excellent mechanical properties. Traditional polyurethane materials are difficult to recycle, causing serious resource waste and environmental pollution. Therefore, the preparation of recyclable polyurethane is urgent for sustainable green development. Generally, the dynamic cross-linking strategy is an effective strategy to realize the preparation of recyclable polyurethane, but the dynamic cross-linked polymer network has weak strength, which leads to a serious decline in mechanical properties and limits its practical application value.

[0004] Cellulose, as the most abundant natural biomass resource in the world, has the advantages of renewability, high strength and multiple active hydroxyl groups, and has been widely used in the fields of synthetic plastics, adhesives, coatings and the like for several centuries. It can replace petroleum-based products to achieve green and sustainable development and has broad application prospects. The multi-hydroxyl structure enables maleimide to be easily introduced into the cellulose skeleton through chemical modification to realize the controllable construction of maleimide-modified cellulose macromolecular cross-linking agent. The linear polymer can be prepared into recyclable dynamic thermosetting polyurethane through Diels-Alder reaction. Therefore, by preparing high-toughness recyclable bio-based thermosetting polyurethane, the environmental pollution caused by the difficulty of recycling and reprocessing of traditional polyurethane materials can be solved, which has important significance for further expanding the application range of cellulose and improving the utilization value of cellulose. SUMMARY

[0005] The application aims to overcome the characteristics of polyurethane that is difficult to recycle and has poor mechanical properties, and provides a high-toughness recyclable bio-based polyurethane.

[0006] Technical scheme: In order to achieve the above purpose, the technical scheme adopted by the application is:

[0007] A high-toughness recyclable bio-based polyurethane has the following general structure:

[0008]

[0009] wherein R is a characteristic functional group of microcrystalline cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, which is H or any one of -CH3, -CH2CH3, -CH2COOH, -CH2CH2OH, -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 application also provides a preparation method of the high-toughness recyclable bio-based polyurethane.

[0011] Step 1, the dithiol, 2-(tert-butylamino)ethyl methacrylate and the photoinitiator are dissolved in a good solvent in a certain molar ratio and reacted under ultraviolet light at 25-40℃ for 6-10h to prepare precursor 1;

[0012] Step 2, the 2,5-furandimethanol, the oligomer polyol, the precursor 1, the diisocyanate and the catalyst are dissolved in a good solvent in a certain molar ratio and reacted at 80-100℃ for 1-3h to prepare a linear polymer;

[0013] Step 3, the linear polymer and the maleimide-modified cellulose are dissolved in a good solvent in a certain mass ratio and poured into a mold, and after the solvent is volatilized, the high-toughness recyclable bio-based polyurethane is prepared by reacting at 30-50℃ for 12-24h.

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

[0016] Preferably, the 2,5-furandimethanol, the oligomer polyol, the precursor 1, the diisocyanate and the catalyst are in a certain molar ratio of 2,5-furandimethanol: 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 or mixture of two or more of polytetrahydrofuran diol, polypropylene oxide diol, polycaprolactone diol, polycarbonate diol.

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

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

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

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

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

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

[0024] (2) The high-strength and high-toughness recyclable bio-based polyurethane can be used as a new type of bio-based polyurethane, which has excellent mechanical properties (strength up to 55.5 MPa, toughness up to 144.25 MJ / m 3 ), and through the introduction of Diels-Alder bonds and steric urea bonds, the damaged network can be rearranged by taking advantage of the characteristics of thermal dissociation and cooling recombination, realizing efficient reprocessing of bio-based polyurethane, meeting the requirements of the green development strategy, and being suitable for a wide range of applications. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The infrared spectrum of methyl methacrylate-2-(tert-butylamino)ethyl ester, precursor 1 in Example 1.

[0026] Figure 2Uniaxial tensile stress-strain curves of the high-toughness recyclable bio-based polyurethane before and after recycling in Example 1. DETAILED DESCRIPTION

[0027] The present application is further illustrated by the following examples and specific embodiments, which are intended to be illustrative only and not limiting of the scope of the application. Various modifications of the application in addition to those described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are intended to fall within the scope of the appended claims.

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

[0029] Example 1

[0030] A method for preparing a high-toughness recyclable bio-based polyurethane, this embodiment uses ethyl cellulose to prepare a high-toughness recyclable bio-based polyurethane, including the following steps:

[0031] First, 1,6-hexanedithiol, 2-(tert-butylamino)ethyl methacrylate, and 2-hydroxy-2-methylpropiophenone are 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 9h to prepare precursor 1, and the reaction process is as follows:

[0032]

[0033] Second, 2,5-furandimethanol, polytetrahydrofuran diol, precursor 1, isophorone diisocyanate, and dibutyltin dilaurate are reacted at a molar ratio of [2,5-furandimethanol]: [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, and the reaction process is as follows:

[0034]

[0035] Third, 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, poured into a mold, and after the solvent is volatilized, a high-toughness recyclable bio-based polyurethane is prepared by reacting at 40°C for 18h, and the reaction process is as follows:

[0036]

[0037] In addition, the preparation of the precursor 1 is based on the thiol-ene click reaction, the carbon-carbon double bond reacts with the thiol under the action of the initiator and light; the linear polymer is based on the reaction of isocyanate with hydroxyl and amino under the action of catalyst and heating to generate urethane bond and urea bond; the preparation of the bio-based polyurethane is based on the Diels-Alder reaction, the maleimide group reacts with the furan group to generate the double addition reaction, so that the maleimide modified cellulose is crosslinked with the linear polymer to finally obtain the bio-based polyurethane.

[0038] Example 2

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

[0040] In the first step, 1,6-hexanedithiol, 2-(tert-butylamino)ethyl methacrylate and 2-hydroxy-2-methylpropiophenone are 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 10h to prepare the precursor 1.

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

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

[0043] Example 3

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

[0045] In the first step, 1,6-hexanedithiol, 2-(tert-butylamino)ethyl methacrylate and 2-hydroxy-2-methylpropiophenone are 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 6h to prepare the precursor 1.

[0046] Second step, 2,5-furandimethanol, polytetrahydrofuran diol, precursor 1, isophorone diisocyanate, dibutyltin dilaurate were reacted at 100℃ for 1h with molar ratio [2,5-furandimethanol]:[polytetrahydrofuran diol]:[precursor 1]:[isophorone diisocyanate]:[dibutyltin dilaurate]=1:0.8:0.2:2.0:0.01 to prepare linear polymer.

[0047] Third step, linear polymer, maleimide modified ethyl cellulose were dissolved in tetrahydrofuran with mass ratio [linear polymer]:[maleimide modified ethyl cellulose]=1:0.06, then poured into a mold, and reacted at 50℃ for 12h after the solvent evaporated to prepare high toughness recyclable bio-based polyurethane.

[0048] Example 4

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

[0050] First step, 1,3-propanedithiol, 2-(tert-butylamino)ethyl methacrylate, 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran with molar ratio [1,3-propanedithiol]:[2-(tert-butylamino)ethyl methacrylate]:[2-hydroxy-2-methylpropiophenone]=2:1:0.05, and reacted at 30℃ for 8h to prepare precursor 1.

[0051] Second step, 2,5-furandimethanol, polycaprolactone diol, precursor 1, isophorone diisocyanate, dibutyltin dilaurate were reacted at 100℃ for 2h with molar ratio [2,5-furandimethanol]:[polycaprolactone diol]:[precursor 1]:[isophorone diisocyanate]:[dibutyltin dilaurate]=1:0.9:0.3:2.2:0.005 to prepare linear polymer.

[0052] Third step, linear polymer, maleimide modified methyl cellulose were dissolved in tetrahydrofuran with mass ratio [linear polymer]:[maleimide modified methyl cellulose]=1:0.08, then poured into a mold, and reacted at 30℃ for 24h after the solvent evaporated to prepare high toughness recyclable bio-based polyurethane.

[0053] Example 5

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

[0055] First step, 1,8-octanedithiol, 2-(tert-butylamino)ethyl methacrylate, 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran at 40℃ for 6h to prepare precursor 1 with molar ratio [1,8-octanedithiol]:[2-(tert-butylamino)ethyl methacrylate]:[2-hydroxy-2-methylpropiophenone]=2:1:0.03;

[0056] Second step, 2,5-furandimethanol, polytetrahydrofuran diol, precursor 1, toluene-2,4-diisocyanate, dibutyltin dilaurate were reacted at 90℃ for 3h to prepare linear polymer with molar ratio [2,5-furandimethanol]:[polytetrahydrofuran diol]:[precursor 1]:[toluene-2,4-diisocyanate]:[dibutyltin dilaurate]=1:0.9:0.2:2.1:0.003.

[0057] Third step, linear polymer, maleimide-modified hydroxyethyl cellulose were dissolved in tetrahydrofuran with mass ratio [linear polymer]:[maleimide-modified hydroxyethyl cellulose]=1:0.09, then poured into a mold, and reacted at 50℃ for 12h after the solvent evaporated to prepare high-toughness recyclable bio-based polyurethane.

[0058] Example 6

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

[0060] First step, 1,4-benzenedithiol, 2-(tert-butylamino)ethyl methacrylate, 2-hydroxy-2-methylpropiophenone were dissolved in tetrahydrofuran at 25℃ for 10h to prepare precursor 1 with molar ratio [1,4-benzenedithiol]:[2-(tert-butylamino)ethyl methacrylate]:[2-hydroxy-2-methylpropiophenone]=2:1:0.06.

[0061] Second step, 2,5-furandimethanol, polycarbonate diol, precursor 1, p-phenylene diisocyanate, triethylenediamine were reacted at 80℃ for 2h to prepare linear polymer with molar ratio [2,5-furandimethanol]:[polycarbonate diol]:[precursor 1]:[p-phenylene diisocyanate]:[triethylenediamine]=1:1:0.2:2.2:0.01.

[0062] Third step, linear polymer, maleimide-modified hydroxypropyl cellulose were dissolved in tetrahydrofuran with mass ratio [linear polymer]:[maleimide-modified hydroxypropyl cellulose]=1:0.06, then poured into a mold, and reacted at 30℃ for 24h after the solvent evaporated to prepare high-toughness recyclable bio-based polyurethane.

[0063] Example 7

[0064] This example utilizes carboxymethyl cellulose to prepare high toughness recyclable bio-based polyurethane, including the following steps:

[0065] First step, 1,6-hexanedithiol, 2-(tert-butylamino)ethyl methacrylate, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide were dissolved in dimethyl sulfoxide at a molar ratio [1,6-hexanedithiol]:[2-(tert-butylamino)ethyl methacrylate]:[diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide]=2:1:0.05 at 40℃ for 6h to prepare precursor 1;

[0066] Second step, 2,5-furandimethanol, polypropylene glycol, precursor 1, hexamethylene diisocyanate, stannous octoate were reacted at a molar ratio [2,5-furandimethanol]:[polypropylene glycol]:[precursor 1]:[hexamethylene diisocyanate]:[stannous octoate]=1:1:0.2:2.2:0.003 at 80℃ for 3h to prepare linear polymer.

[0067] Third step, linear polymer, maleimide modified carboxymethyl cellulose were dissolved in dimethyl sulfoxide at a mass ratio [linear polymer]:[maleimide modified carboxymethyl cellulose]=1:0.09, poured into a mold, and after the solvent was volatilized, reacted at 40℃ for 18h to prepare high toughness recyclable bio-based polyurethane.

[0068] Example 8

[0069] This example utilizes microcrystalline cellulose to prepare high toughness recyclable bio-based polyurethane, including the following steps:

[0070] First step, 1,6-hexanedithiol, 2-(tert-butylamino)ethyl methacrylate, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide were dissolved in N,N-dimethylformamide at a molar ratio [1,6-hexanedithiol]:[2-(tert-butylamino)ethyl methacrylate]:[diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide]=2:1:0.05 at 40℃ for 6h to prepare precursor 1;

[0071] Second step, 2,5-furandimethanol, polycaprolactone diol, precursor 1, dicyclohexylmethane diisocyanate, tetramethylbutanediamine were reacted at a molar ratio [2,5-furandimethanol]:[polycaprolactone diol]:[precursor 1]:[dicyclohexylmethane diisocyanate]:[tetramethylbutanediamine]=1:0.8:0.4:2.2:0.005 at 80℃ for 3h to prepare linear polymer.

[0072] The third step involves dissolving the linear polymer and maleimide-modified microcrystalline cellulose in N,N-dimethylformamide at a mass ratio of [linear polymer]:[maleimide-modified microcrystalline cellulose] = 1:0.08, pouring the solution into a mold, and reacting at 30°C for 20 hours after the solvent has evaporated to prepare a high-strength, tough, recyclable bio-based polyurethane.

[0073] like Figure 1 The image shows the infrared spectra of 2-(tert-butylamino)ethyl methacrylate and precursor 1 in Example 1. The image shows the 1637 cm⁻¹ spectrum. -1 745cm -1 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 indicate the successful preparation of precursor 1.

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

[0075] Tests revealed that the high-strength, high-toughness, recyclable bio-based polyurethanes prepared in Examples 1-8 above possess high strength and high toughness and can be recycled through reprocessing, thus extending the service life of bio-based polyurethanes and expanding their application areas.

[0076] The bio-based polyurethane of this invention contains two types of dynamic covalent bonds: hindered urea bonds and Diels-Alder bonds, as well as multiple dynamic hydrogen bonds. During the tensile process, the weaker hydrogen bonds in the multiple hydrogen bonds break first, dissipating energy. As the tensile strain increases, the stronger hydrogen bonds break and continue to dissipate energy, achieving high strength and high toughness. During material recycling, the hydrogen bonds, hindered urea bonds, and Diels-Alder bonds recombine after thermal dissociation, causing the bio-based polyurethane network to rearrange. Therefore, the interaction of dynamic covalent bonds and multiple hydrogen bonds gives the bio-based polyurethane the advantages of high strength, toughness, and recyclability.

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

[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

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

2. A method for preparing the high-strength, tough, recyclable bio-based polyurethane as described in claim 1, characterized in that, Includes the following steps: Step 1: Dithiol, 2-(tert-butylamino)ethyl methacrylate, and photoinitiator are dissolved in a good solvent at a certain molar ratio and reacted at 25-40 °C under ultraviolet light for 6-10 h to prepare precursor 1; Step 2: Dissolve 2,5-furandiethanol, oligomeric polyol, precursor 1, diisocyanate, and catalyst in a good solvent at a certain molar ratio and react at 80-100 °C for 1-3 h to prepare linear polymer; Step 3: Dissolve the linear polymer and maleimide-modified cellulose in a good solvent at a certain mass ratio and pour the solution into a mold. After the solvent evaporates, react at 30~50 °C for 12~24 h to prepare high-strength, tough, recyclable bio-based polyurethane.

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

5. The preparation method according to claim 4, characterized in that: The 2,5-furandiethanol, oligomer polyol, precursor 1, diisocyanate, and catalyst are in a certain molar ratio of 2,5-furandiethanol: 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 oligomeric polyol is any one or a mixture of two or more of the following: polytetrahydrofuran diol, polypropylene oxide diol, polycaprolactone diol, and polycarbonate diol.

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

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

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 or a mixture of two or more of the following: maleimide-modified methylcellulose, maleimide-modified ethylcellulose, maleimide-modified hydroxyethylcellulose, maleimide-modified hydroxypropylcellulose, maleimide-modified carboxymethylcellulose, and maleimide-modified microcrystalline cellulose.

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