High-strength and high-toughness cellulose-based bioplastic, preparation method and application

Abstract

The application relates to a high-strength and high-toughness cellulose-based biological plastic, a preparation method and application, and belongs to the field of biological plastics. A small amount of high-boiling-point solvent is used as a plasticizer of cellulose and its derivatives, the plasticizer is also a solvent of a modifier and a crosslinking agent, a large number of hydroxyl groups on the cellulose and its derivatives are used as reactive points, crosslinked cellulose containing the plasticizer is prepared through thermoplastic processing by means of low-temperature chemistry, the crosslinked cellulose is soaked in a phase separation liquid to remove the plasticizer and induce microphase separation of the crosslinked cellulose, and the microphase separation structure is regulated through cellulose chemical structure regulation, microphase separation conditions and post-treatment methods. The obtained microphase separation cellulose has a cellulose content of greater than or equal to 80 wt%, a tensile strength of greater than or equal to 60 MPa and an elongation at break of greater than or equal to 40%, and shows high-strength and high-toughness characteristics. The high-strength and high-toughness cellulose-based biological plastic can be prepared through thermoplastic processing combined with post-treatment, the preparation method is simple, the performance is excellent, and industrial production can be easily realized.

Description

Technical Field

[0001] This invention belongs to the field of bio-based plastics, specifically relating to a high-strength and high-toughness cellulose-based bioplastic, its preparation method, and its application. Background Technology

[0002] To date, global production of synthetic plastics has exceeded 8 billion tons. However, synthetic plastics are primarily petroleum-based, which severely exacerbates the global depletion of oil resources. It is predicted that by 2025, synthetic polymers will consume 20% of global oil resources. Bio-based materials are renewable, and using bio-based raw materials to prepare high-performance bio-based plastics is one of the effective means to alleviate the depletion of oil resources.

[0003] Cellulose is the most abundant non-food bio-based polymer on Earth, possessing outstanding advantages such as abundant source, renewability, high modulus, and low price, making it an ideal material to replace petroleum-based polymers. However, the cellulose backbone consists of rigid β-D-pyranose glucose units rich in hydroxyl groups. This rigid backbone, high crystallinity, and high-density hydrogen bonding limit the melting temperature (T0) of cellulose. m The high strength of cellulose makes it difficult to thermoplasticize, and its processing relies on solution processing, which is difficult to scale up. Furthermore, the rigid backbone, high crystallinity, and high-density hydrogen bonds severely restrict the mobility of cellulose chain segments, resulting in poor toughness of cellulose-based plastics. Regenerated cellulose membranes prepared by casting using ionic liquids typically have a tensile strength of 60–120 MPa, while their elongation at break is only 6–9%. Adding plasticizers and chemical modification can impart certain thermoplastic processing properties to cellulose and its derivatives and improve their toughness, but this significantly reduces their strength and causes problems such as plasticizer migration and water sensitivity. Therefore, based on reasonable structural design, the preparation of high-strength and high-toughness cellulose-based plastics through thermoplastic processing has significant scientific value and practical significance. Summary of the Invention

[0004] To address the problems in existing technologies, this invention provides a high-strength, high-toughness cellulose-based bioplastic, its preparation method, and its applications. A small amount of high-boiling-point solvent is used as a plasticizer for cellulose and its derivatives, and this plasticizer also serves as a solvent for both the modifier and the crosslinking agent. Utilizing the numerous hydroxyl groups on cellulose and its derivatives as reactive sites, crosslinked cellulose containing the plasticizer is prepared through thermoplastic processing using low-temperature chemistry. The crosslinked cellulose is then immersed in a phase separation solution to remove the plasticizer and induce microphase separation. The microphase separation structure is controlled by adjusting the cellulose chemical structure, microphase separation conditions, and post-treatment methods. The resulting microphase-separated cellulose has a cellulose content ≥80 wt%, a tensile strength ≥60 MPa, and an elongation at break ≥40%, exhibiting high strength and high toughness. This high-strength, high-toughness cellulose-based bioplastic can be prepared through thermoplastic processing combined with post-treatment; the preparation method is simple, the performance is excellent, and it is easily industrialized.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A high-strength and high-toughness cellulose-based bioplastic, wherein the cellulose content is ≥80wt%, the tensile strength is ≥65MPa, and the elongation at break is ≥40%.

[0007] Furthermore, the high-strength and high-toughness cellulose-based bioplastic is a microphase-separated cross-linked polymer, prepared by microphase separation of cellulose or its derivatives, ethyl isocyanate acrylate, modifier and cross-linking agent.

[0008] Further, the cellulose or its derivative is one or more of plant cellulose, microcrystalline cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and cellulose acetate; the crosslinking agent is one or more of hexa(3-mercaptopropionic acid) dipentaerythritol ester, tetra(3-mercaptopropionic acid) pentaerythritol ester, tris(3-mercaptopropionic acid) trimethylolpropane ester, ethylene glycol dimercaptoacetate, 1,4-butanedithiol, and 1,6-hexanedithiol; and the modifier is one or more of n-dodecyl mercaptan, n-tetradecyl mercaptan, 1-hexanethiol, 2-ethylhexyl mercaptan, n-butyl isocyanate, and ethyl isocyanate.

[0009] Furthermore, the content of cellulose or its derivatives is 80-95 wt%, the content of ethyl isocyanate acrylate is 3-10 wt%, the content of modifier is 0-10 wt%, and the content of crosslinking agent is 2-10 wt%.

[0010] A method for preparing high-strength and high-toughness cellulose-based bioplastics, the specific steps of which are as follows:

[0011] (1) Add solvent-based plasticizer to cellulose or its derivative powder and mechanically stir for 3-5 minutes to obtain preliminarily plasticized cellulose;

[0012] (2) Add the cellulose that has been preliminarily plasticized in step (1) to a mixer or extruder and stir to make the cellulose uniformly plasticized. Then add ethyl isocyanate acrylate, crosslinking agent and modifier in sequence. Stirring is required after each addition to achieve uniform blending and in-situ modification.

[0013] (3) The blend obtained in step (2) is hot-pressed to obtain sheet-like cross-linked cellulose; then the cross-linked cellulose is soaked in a phase separation liquid to separate its microphases, and dried at room temperature and in a vacuum oven to obtain a cellulose-based plastic with microphase separation.

[0014] Further, in step (1), the solvent-based plasticizer is one or more of dimethyl sulfoxide, ionic liquid (1-butyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium acetate, 1-allyl-3-methylimidazolium chloride), and triethyl phosphate, and the mass ratio of cellulose to solvent-based plasticizer is 100:(40-100).

[0015] Further, in step (2), the temperature of the internal mixer or extruder is 60-90℃, the rotation speed is 50-80 rpm, the stirring time for uniform plasticization is 3-10 min, the stirring time after adding ethyl isocyanate acrylate is 10-20 min, the stirring time after adding crosslinking agent is 10-20 min, and the stirring time after adding modifier is 10-20 min.

[0016] Further, in step (3), the hot pressing temperature is 100-150℃, the hot pressing time is 10-30 min, the phase separation liquid is one or more of water, methanol, ethanol, and dimethylacetamide, the soaking time is 0.5-3 hours, the soaking times are 3-5 times, the room temperature drying time is 6-24 hours, and the vacuum oven drying time is 6-24 hours.

[0017] The above-mentioned application of a high-strength and high-toughness cellulose-based bioplastic allows the cellulose-based bioplastic to replace petroleum-based plastics as packaging materials, electrical appliance housings, and structural materials.

[0018] Those skilled in the art may also add other optional additives as needed to obtain better performance. These additives can be selected from anti-aging agents, preservatives, bactericides, antistatic agents, crosslinking agents, pigments, fillers, fragrances, etc., and can be added simultaneously or individually.

[0019] The beneficial effects of this invention are:

[0020] (1) This invention is the first to efficiently prepare cross-linked cellulose through thermoplastic processing: a small amount of solvent is used as a plasticizer for cellulose or its derivatives, and the solvent is also a solvent for both the modifier and the cross-linking agent; the hydroxyl groups on cellulose and its derivatives are used as reactive sites, and combined with chemical reactions that can occur at low temperatures, cross-linked cellulose can be prepared through thermoplastic processing. This method and idea have not been reported before.

[0021] (2) This invention is the first to prepare cellulose-based plastic with both high strength and high deformability based on the microphase separation strategy: the microphase separation strategy is mainly used for the toughening and functionalization of hydrogels, and its application in cellulose-based plastics has not been reported; the cellulose-based plastics reported so far are difficult to achieve both high strength (≥65MPa) and high deformability (≥40%).

[0022] (3) The main raw materials used in this invention are cellulose and its derivatives, which have the advantages of wide availability of raw materials, renewable raw materials and low price.

[0023] (4) The cellulose-based bioplastic prepared by this invention has the advantages of high bio-based content, thermoplastic processing and high strength and toughness. It can replace petroleum-based plastics in packaging materials, electrical housings and structural materials, and is expected to alleviate the problem of petroleum resource depletion. Detailed Implementation

[0024] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that the following specific embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention. If those skilled in the art make some non-essential adjustments and improvements to the present invention based on the above content, they shall still fall within the protection scope of the present invention.

[0025] Comparative Example 1:

[0026] The preparation method of cast cellulose membrane includes the following steps:

[0027] (1) Dissolve 25g of hydroxyethyl cellulose in 2500ml of deionized water and stir at room temperature for 2h to obtain an aqueous solution of hydroxyethyl cellulose;

[0028] (2) Pour the hydroxyethyl cellulose solution into a tetrafluoroethylene petri dish, dry it slowly at room temperature for two days, and then dry it in a vacuum oven at 60°C until constant weight to obtain a hydroxyethyl cellulose membrane.

[0029] Comparative Example 2:

[0030] The preparation method of cross-linked cellulose-based plastics in solution includes the following steps:

[0031] (1) Add 25g of hydroxyethyl cellulose to 2500ml of DMSO and stir for 1h to obtain a hydroxyethyl cellulose solution with a concentration of 1w / v%. Heat the solution to 60℃, add 5g of ethyl isocyanate acrylate (MOI) under continuous stirring, and react at 60℃ for 3h to obtain an acrylated hydroxyethyl cellulose solution.

[0032] (2) At room temperature, 4g of pentaerythritol tetrakis(3-mercaptopropionic acid) (PEMP) was added dropwise to an acrylated hydroxyethyl cellulose solution. After stirring at 1000rpm for 2h, a gelled hydroxyethyl cellulose cross-linked body was obtained. The gel was cut into pieces and washed four times with ethanol to remove DMSO. The washed particles were dried in an oven at 60℃ to constant weight to obtain hydroxyethyl cellulose cross-linked particles that can be hot-pressed.

[0033] (3) The hydroxyethyl cellulose cross-linked particles were hot-pressed at 140°C for 30 min to obtain a cellulose-based bioplastic film.

[0034] Comparative Example 3:

[0035] The preparation method of non-microphase separated cellulose-based bioplastics includes the following steps:

[0036] (1) Add 10g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0037] (2) Add the above plasticized cellulose to a mixer and stir at 70°C at 60 rpm for 5 min. Add DMSO solution of ethyl isocyanate acrylate (MOI) (2g MOI, 8g DMSO) and stir for 20 min. Then add DMSO solution of crosslinking agent pentaerythritol tetrakis(3-mercaptopropionic acid) (PEMP) (1.6g PEMP, 8g DMSO) and stir for 20 min.

[0038] (3) The above blend was hot-pressed at 140°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then dried at room temperature for 48 hours and then dried in a vacuum oven at 60°C for 48 hours to obtain cellulose-based bioplastic.

[0039] Example 1:

[0040] The preparation method of microphase-separated cellulose-based bioplastics includes the following steps:

[0041] (1) Add 10g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0042] (2) Add the above plasticized cellulose to a mixer and stir at 70°C at 60 rpm for 5 min. Add DMSO solution of ethyl isocyanate acrylate (MOI) (2g MOI, 8g DMSO) and stir for 20 min. Then add DMSO solution of crosslinking agent pentaerythritol tetrakis(3-mercaptopropionic acid) (PEMP) (1.6g PEMP, 8g DMSO) and stir for 20 min.

[0043] (3) The above blend was hot-pressed at 140°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then soaked in water for 40 min each time, for 3 times, and then dried at room temperature for 24 hours and in a vacuum oven at 60°C for 24 hours to obtain cellulose-based bioplastic.

[0044] Example 2:

[0045] The preparation method of microphase-separated cellulose-based bioplastics includes the following steps:

[0046] (1) Add 10g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0047] (2) Add the above plasticized cellulose to a mixer and stir at 60 rpm for 5 min at 70°C. Add a DMSO mixed solution of ethyl isocyanate acrylate (MOI) and n-butyl isocyanate (BIC) (2g MOI, 1g BIC, 8g DMSO) and stir for 20 min. Then add a DMSO solution of pentaerythritol tetrakis(3-mercaptopropionic acid) (PEMP) crosslinking agent (1.6g PEMP, 8g DMSO) and stir for 20 min.

[0048] (3) The above blend was hot-pressed at 140°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then soaked in water for 40 min each time, for 3 times, and then dried at room temperature for 24 hours and in a vacuum oven at 60°C for 24 hours to obtain cellulose-based bioplastic.

[0049] Example 3:

[0050] The preparation method of microphase-separated cellulose-based bioplastics includes the following steps:

[0051] (1) Add 10g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0052] (2) Add the above plasticized cellulose into a mixer and stir at 60 rpm for 5 min at 70°C. Add DMSO solution of ethyl isocyanate acrylate (MOI) (2 g MOI, 8 g DMSO) and stir for 20 min. Then add DMSO solution of crosslinking agent ethylene glycol dimercaptoacetate (EMA) (1.4 g EMA, 8 g DMSO) and stir for 20 min.

[0053] (3) The above blend was hot-pressed at 140°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then soaked in water for 40 min each time, for 3 times, and then dried at room temperature for 24 hours and in a vacuum oven at 60°C for 24 hours to obtain cellulose-based bioplastic.

[0054] Example 4:

[0055] The preparation method of microphase-separated cellulose-based bioplastics includes the following steps:

[0056] (1) Add 10g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0057] (2) Add the above plasticized cellulose to a mixer and stir at 70°C at 60 rpm for 5 min. Add DMSO solution of ethyl isocyanate acrylate (MOI) (2g MOI, 8g DMSO) and stir for 20 min. Then add DMSO solution of crosslinking agent hexa(3-mercaptopropionic acid) dipentaerythritol ester (DHMP) (1.7g DHMP, 8g DMSO) and stir for 20 min.

[0058] (3) The above blend was hot-pressed at 140°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then soaked in water for 40 min each time, for 3 times, and then dried at room temperature for 24 hours and in a vacuum oven at 60°C for 24 hours to obtain cellulose-based bioplastic.

[0059] Example 5:

[0060] The preparation method of microphase-separated cellulose-based bioplastics includes the following steps:

[0061] (1) Add 10g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0062] (2) Add the above plasticized cellulose to a mixer and stir at 60 rpm for 5 min at 70°C. Add a DMSO solution of ethyl isocyanate acrylate (MOI) (2 g MOI, 8 g DMSO) and stir for 20 min. Then add a DMSO solution of crosslinking agent ethylene glycol dimercaptoacetate (EMA) and hexa(3-mercaptopropionic acid) dipentaerythritol ester (DHMP) (0.7 g EMA, 0.8 g DHMP, 8 g DMSO) and stir for 20 min.

[0063] (3) The above blend was hot-pressed at 140°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then soaked in water for 40 min each time, for 3 times, and then dried at room temperature for 24 hours and in a vacuum oven at 60°C for 24 hours to obtain cellulose-based bioplastic.

[0064] Example 6:

[0065] The preparation method of microphase-separated cellulose-based bioplastics includes the following steps:

[0066] (1) Add 10g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0067] (2) Add the above plasticized cellulose to a mixer and stir at 60 rpm for 5 min at 70°C. Add DMSO solution of ethyl isocyanate acrylate (MOI) (2 g MOI, 8 g DMSO) and stir for 20 min. Then add DMSO solution of crosslinking agent tris(3-mercaptopropionic acid) trimethylolpropane ester (TPMP) (1.7 g TPMP, 8 g DMSO) and stir for 20 min.

[0068] (3) The above blend was hot-pressed at 140°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then soaked in water for 40 min each time, for 3 times, and then dried at room temperature for 24 hours and in a vacuum oven at 60°C for 24 hours to obtain cellulose-based bioplastic.

[0069] Example 7:

[0070] The preparation method of microphase-separated cellulose-based bioplastics includes the following steps:

[0071] (1) Add 10g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0072] (2) Add the above plasticized cellulose to a mixer and stir at 60 rpm for 4 min at 90°C. Add DMSO solution of ethyl isocyanate acrylate (MOI) (2 g MOI, 8 g DMSO) and stir for 10 min. Then add DMSO solution of pentaerythritol tetrakis(3-mercaptopropionic acid) (PEMP) crosslinking agent (1.6 g PEMP, 8 g DMSO) and stir for 10 min.

[0073] (3) The above blend was hot-pressed at 150°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then soaked in water for 40 min each time, for 3 times, and then dried at room temperature for 24 hours and in a vacuum oven at 60°C for 24 hours to obtain cellulose-based bioplastic.

[0074] Example 8:

[0075] The preparation method of microphase-separated cellulose-based bioplastics includes the following steps:

[0076] (1) Add 10g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0077] (2) Add the above plasticized cellulose to a mixer and stir at 60 rpm for 5 min at 60 °C. Add DMSO solution of ethyl isocyanate acrylate (MOI) (2 g MOI, 8 g DMSO) and stir for 20 min. Then add DMSO solution of pentaerythritol tetrakis(3-mercaptopropionic acid) (PEMP) crosslinking agent (1.6 g PEMP, 8 g DMSO) and stir for 20 min.

[0078] (3) The above blend was hot-pressed at 120°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then soaked in water for 40 min each time, for 3 times, and then dried at room temperature for 24 hours and in a vacuum oven at 60°C for 24 hours to obtain cellulose-based bioplastic.

[0079] Example 9:

[0080] The preparation method of microphase-separated cellulose-based bioplastics includes the following steps:

[0081] (1) Add 10g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0082] (2) Add the above plasticized cellulose into a mixer and stir at 70°C at 60 rpm for 5 min. Add a DMSO solution of ethyl isocyanate acrylate (MOI) (1 g MOI, 8 g DMSO) and stir for 20 min. Then add a DMSO solution of pentaerythritol tetrakis(3-mercaptopropionic acid) (PEMP) crosslinking agent (0.8 g PEMP, 8 g DMSO) and stir for 20 min.

[0083] (3) The above blend was hot-pressed at 140°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then soaked in water for 40 min each time, for 3 times, and then dried at room temperature for 24 hours and in a vacuum oven at 60°C for 24 hours to obtain cellulose-based bioplastic.

[0084] Example 10:

[0085] The preparation method of microphase-separated cellulose-based bioplastics includes the following steps:

[0086] (1) Add 15g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0087] (2) Add the above plasticized cellulose to a mixer and stir at 70°C at 60 rpm for 5 min. Add DMSO solution of ethyl isocyanate acrylate (MOI) (2g MOI, 5g DMSO) and stir for 20 min. Then add DMSO solution of crosslinking agent pentaerythritol tetrakis(3-mercaptopropionic acid) (PEMP) (1.6g PEMP, 5g DMSO) and stir for 20 min.

[0088] (3) The above blend was hot-pressed at 140°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then soaked in water for 40 min each time, for 3 times, and then dried at room temperature for 24 hours and in a vacuum oven at 60°C for 24 hours to obtain cellulose-based bioplastic.

[0089] Example 11:

[0090] The preparation method of microphase-separated cellulose-based bioplastics includes the following steps:

[0091] (1) Add 20g DMSO dropwise to 25g hydroxyethyl cellulose and stir with a glass rod for 3min;

[0092] (2) Add the above plasticized cellulose to a mixer and stir at 60 rpm for 5 min at 70°C. Add DMSO solution of ethyl isocyanate acrylate (MOI) (2g MOI, 3g DMSO) and stir for 20 min. Then add DMSO solution of pentaerythritol tetrakis(3-mercaptopropionic acid) (PEMP) crosslinking agent (1.6g PEMP, 3g DMSO) and stir for 20 min.

[0093] (3) The above blend was hot-pressed at 140°C for 30 min to obtain sheet-like cross-linked cellulose; the cross-linked cellulose was then soaked in water for 40 min each time, for 3 times, and then dried at room temperature for 24 hours and in a vacuum oven at 60°C for 24 hours to obtain cellulose-based bioplastic.

[0094] Table 1 Typical performance of Comparative Examples 1-3 and Examples 1-11

[0095]

[0096]

[0097] The above results indicate that the cellulose material prepared by the casting method (Comparative Example 1) has lower tensile strength and elongation at break. The cross-linked cellulose prepared by the solution method (Comparative Example 2) and the cross-linked cellulose without microphase separation (Comparative Example 3) show slightly improved mechanical properties compared to Comparative Example 1, but are still relatively poor. Compared to the comparative examples, the cross-linked cellulose with microphase separation proposed in this invention (Examples 1-11) exhibits excellent mechanical properties, with tensile strength and elongation at break significantly higher than the comparative examples. Furthermore, the cellulose-based bioplastics obtained by this method possess high bio-based content, high strength, and high toughness. By controlling the processing conditions, the content of cross-linking components, and the content of modifiers, the strength and toughness of the bioplastics can be controlled within a certain range, but the final strength is still higher than 65 MPa, and the final elongation at break is still higher than 40%.

[0098] Those skilled in the art should understand that the above description is merely a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-strength, high-toughness cellulose-based bioplastic, characterized in that, The high-strength, high-toughness cellulose-based bioplastic has a cellulose content ≥80wt%, a tensile strength ≥65MPa, and an elongation at break ≥40%. The preparation method of the high-strength, high-toughness cellulose-based bioplastic is as follows: (1) Add solvent-based plasticizer to cellulose or its derivative powder and mechanically stir for 3-5 minutes to obtain preliminarily plasticized cellulose; (2) Add the cellulose that has been preliminarily plasticized in step (1) to a mixer or extruder and stir to make the cellulose uniformly plasticized. Then add ethyl isocyanate acrylate, crosslinking agent and modifier in sequence. Stirring is required after each addition to achieve uniform blending and in-situ modification. (3) The blend obtained in step (2) is hot-pressed to obtain sheet-like cross-linked cellulose; The cross-linked cellulose is then immersed in a phase separation solution to separate its microphases. After drying at room temperature and in a vacuum oven, a cellulose-based plastic with microphase separation is obtained.

2. The high-strength, high-toughness cellulose-based bioplastic according to claim 1, characterized in that, The cellulose or its derivatives are one or more of plant cellulose, microcrystalline cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and cellulose acetate; the crosslinking agent is one or more of hexa(3-mercaptopropionic acid) dipentaerythritol ester, tetra(3-mercaptopropionic acid) pentaerythritol ester, tris(3-mercaptopropionic acid) trimethylolpropane ester, ethylene glycol dimercaptoacetate, 1,4-butanedithiol, and 1,6-hexanedithiol; the modifier is one or more of n-dodecyl mercaptan, n-tetradecyl mercaptan, 1-hexanethiol, 2-ethylhexyl mercaptan, n-butyl isocyanate, and ethyl isocyanate.

3. The high-strength, high-toughness cellulose-based bioplastic according to claim 1, characterized in that, The content of cellulose or its derivatives is 80-95 wt%, the content of ethyl isocyanate acrylate is 3-10 wt%, the content of modifier is 0-10 wt%, and the content of crosslinking agent is 2-10 wt%.

4. A method for preparing a high-strength, high-toughness cellulose-based bioplastic according to any one of claims 1-3, characterized in that, The specific steps are as follows: (1) Add solvent-based plasticizer to cellulose or its derivative powder and mechanically stir for 3-5 minutes to obtain preliminarily plasticized cellulose; (2) Add the cellulose that has been preliminarily plasticized in step (1) to a mixer or extruder and stir to make the cellulose uniformly plasticized. Then add ethyl isocyanate acrylate, crosslinking agent and modifier in sequence. Stirring is required after each addition to achieve uniform blending and in-situ modification. (3) The blend obtained in step (2) is hot-pressed to obtain sheet-like cross-linked cellulose; The cross-linked cellulose is then immersed in a phase separation solution to separate its microphases. After drying at room temperature and in a vacuum oven, a cellulose-based plastic with microphase separation is obtained.

5. The method for preparing a cellulose-based bioplastic according to claim 4, characterized in that, In step (1), the solvent-based plasticizer is one or more of dimethyl sulfoxide, ionic liquid, and triethyl phosphate, and the mass ratio of cellulose to solvent-based plasticizer is 100:(40~100).

6. The method for preparing a cellulose-based bioplastic according to claim 4, characterized in that, In step (2), the temperature of the internal mixer or extruder is 60~90°C. o C, the stirring time is 50~80 rpm, the stirring time for uniform plasticization is 3~10 min, the stirring time after adding ethyl isocyanate acrylate is 10~20 min, the stirring time after adding crosslinking agent is 10~20 min, and the stirring time after adding modifier is 10~20 min.

7. The method for preparing a cellulose-based bioplastic according to claim 4, characterized in that, In step (3), the hot pressing temperature is 100~150℃. o C. The hot pressing time is 10~30min, the phase separation liquid is one or more of water, methanol, ethanol, and dimethylacetamide, the soaking time is 0.5~3 hours, the soaking number is 3~5 times, the room temperature drying time is 6~24 hours, and the vacuum oven drying time is 6~24 hours.

8. The application of a high-strength, high-toughness cellulose-based bioplastic according to any one of claims 1-3, or a high-strength, high-toughness cellulose-based bioplastic prepared by any one of claims 5-7, characterized in that, The cellulose-based bioplastics described above can replace petroleum-based plastics as packaging materials, appliance housings, and structural materials.

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