Multifunctional degradable composite film based on bagasse as well as preparation method and application of multifunctional degradable composite film

Abstract

The invention relates to the technical field of high-value utilization of wood fiber biomass, in particular to a multifunctional degradable composite film based on bagasse as well as a preparation method and application of the multifunctional degradable composite film. According to the scheme, aiming at the problems that a cellulose base film is large in brittleness, poor in mechanical property, lack of multifunctional regulation and control and the like, nano lignin particles (LNPs) are adopted as enhancement and functionalization components to cooperatively construct a multi-scale cellulose composite network structure, and the functionalized degradable composite film with high strength, ultraviolet resistance and slow release performance is prepared. The tensile strength of the film is improved from 17 MPa to 73 MPa, and the elongation at break is improved to 20% or above; obvious absorption is shown in an ultraviolet region of 280-320 nm, and the light transmittance is reduced by about 35%; the moisture evaporation rate is reduced by 28%, and the moisture conservation performance is effectively improved; the release period of the urea is prolonged to 40 days, the release amount in the first 10 days is only 18.5%, and the stable slow release effect is achieved. The comprehensive performance is obviously superior to that of a pure cellulose film and a control group without nano particle addition, and a new path is provided for the development of the functional integrated agricultural mulching film.

Description

Technical Field

[0001] This invention relates to the field of high-value utilization technology of lignocellulose biomass, specifically a multifunctional biodegradable composite membrane based on sugarcane bagasse, its preparation method, and its application. Background Technology

[0002] While existing biodegradable agricultural mulch films, primarily based on PLA and PBAT, are biodegradable, they are costly and degrade slowly, making it difficult to simultaneously meet agronomical requirements such as moisture retention, temperature control, weed control, and slow release. Meanwhile, plant fiber biomass materials (such as rice husks, wheat straw, and sugarcane bagasse), as agricultural waste byproducts, have advantages such as wide availability, low price, high renewability, excellent biodegradability, and good environmental compatibility, making them potential raw materials for developing green mulch materials. However, plant fiber-based biodegradable membranes still face the following key technical bottlenecks in practical applications: (1) Existing biomass component separation mainly relies on strong acid and strong alkali chemical methods, which have problems such as environmental pollution and damage to cellulose structure, making it difficult to achieve a green and efficient raw material extraction path; (2) Single cellulose membranes generally have high brittleness, poor tensile properties, and are easily degraded in humid environments due to weak interfacial bonding between fibers; (3) Existing plant-based membranes have single functions and generally lack agronomic auxiliary functions such as photothermal regulation, UV protection, and slow nutrient release, making it difficult to meet the comprehensive needs of crops throughout their entire growth cycle; (4) Current fertilization methods mainly rely on manual topdressing or compound fertilizers applied outside the membrane, which lack a controlled release mechanism that works in synergy with membrane materials, easily leading to problems such as low fertilizer utilization and nutrient loss.

[0003] Therefore, designing a biodegradable composite membrane that integrates structural reinforcement and multifunctional synergy is key to achieving green replacement of agricultural mulch film and sustainable agricultural development. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems in the prior art, the present invention provides a multifunctional biodegradable composite membrane based on sugarcane bagasse, its preparation method and application.

[0005] A multifunctional biodegradable composite membrane based on sugarcane bagasse is prepared by the following steps: (1) Raw material pretreatment: Select the waste residue after sugarcane pressing as raw material, wash it thoroughly with clean water to remove soluble sugar and impurities, dry it to constant weight and then crush it to 60 mesh for later use; this step can ensure the fineness of raw material particles and uniformity of film formation, and control film thickness and dispersibility. (2) One-pot separation of cellulose and lignin by endogenous organic acid: Sugarcane bagasse powder is mixed with organic acid solution and placed in a closed hydrothermal reactor. The mixture is reacted at 120-140℃ for 30-60 minutes to achieve cellulose swelling and release and lignin dissolution. After the reaction is completed, the mixture is filtered to separate the cellulose pulp and the lignin-containing liquid phase. (3) Preparation of nano-lignin particles: The lignin-containing solution is concentrated by rotary evaporation and then slowly added to deionized water under stirring. The lignin molecules are induced to self-assemble into nanoparticles (LNPs) by pH and polarity changes. After freeze-drying or low-temperature concentration, they are ready for use. By controlling the self-assembly conditions, LNPs with good dispersibility with particle size between 100-300 nm can be obtained. (4) Preparation of nano-lignin-cellulose composite slurry: The cellulose slurry obtained in step (2) is compounded with the nano-lignin obtained in step (3) and stirred evenly to form a stable suspension slurry; in order to give it the function of slow release of nutrients, 3-10wt% of micro-nano urea particles are added to construct a synergistic system of membrane-fertilizer integration. (5) Film forming process: The above composite slurry is made into a composite film; finally, it is cut, packaged and ready for use.

[0006] Furthermore, the waste residue is the wet or dry residue obtained from sugarcane after mechanical pressing during the sugar or pulping process. The moisture content of the waste residue does not exceed 15%, and its main chemical components are cellulose, hemicellulose and lignin. It is also basically free of non-biomaterial impurities such as plastics and stones.

[0007] Furthermore, the organic acid is citric acid or oxalic acid.

[0008] Furthermore, the organic acid solution has a concentration of 3-6 wt%.

[0009] Furthermore, the bagasse powder and organic acid solution are mixed at a solid-liquid ratio of 1:10.

[0010] Furthermore, in step (4), the cellulose pulp obtained in step (2) is compounded with the nano-lignin obtained in step (3), specifically in a mass ratio of 3:1 to 5:1.

[0011] Furthermore, the micro-nano urea particles are uniformly dispersed using airflow pulverization or ultrasonic pretreatment.

[0012] Further, in step (5), the above composite slurry is made into a composite film, specifically by uniformly spreading it on a glass plate by casting and drying it at 60°C for 24 hours to obtain a preliminary film material, or by hot pressing (80-100°C, 3-5MPa, maintained for 5-10 minutes) to form a dense composite film.

[0013] A multifunctional biodegradable composite film based on sugarcane bagasse is prepared by the method described above. It can be used for applications in the preparation of agricultural mulch films.

[0014] Compared with the prior art, the technical effects of this invention are reflected in: This invention provides a method for preparing a functionalized biodegradable composite membrane based on agricultural and forestry waste. Using agricultural waste such as sugarcane bagasse as raw materials, and combining green solvent separation with inorganic solvent and strong acid / alkali-free treatment processes, a nano-lignin-cellulose composite network structure is constructed. Through the interfacial filling effect of nano-lignin particles, the mechanical properties of the membrane are significantly enhanced. The tensile strength is increased to 73 MPa, and the elongation at break exceeds 20%, significantly superior to pure cellulose membranes. Simultaneously, the intrinsic aromatic ring structure of lignin endows the membrane with excellent UV absorption capacity (reducing transmittance at 280-320 nm by approximately 35%), and synergistically improves the membrane's heat retention, moisture retention, and weed suppression functions. At the structural level, by constructing a confined nanoporous system, micro- and nano-sized urea is embedded in the membrane to achieve controlled-release. Only 18.5% is released in the first 10 days, and the slow-release period is extended to 40 days, significantly reducing nitrogen loss. The composite membrane has a natural degradation period of 100-150 days in agricultural environments, which can be well matched with the growth periods of crops such as corn and sugarcane. This material integrates green raw materials, structural enhancement, multifunctional integration, and controllable degradation. It is suitable for agricultural mulch film covering, functional biodegradable materials, and the new agricultural film industry, and has good ecological value and broad application prospects. Attached Figure Description

[0015] Figure 1 The figure shows the tensile strength and elongation at break of the multifunctional biodegradable composite membrane based on sugarcane bagasse prepared in Example 1.

[0016] Figure 2 The ultraviolet absorbance of the multifunctional biodegradable composite membrane based on sugarcane bagasse prepared in Example 1 is shown.

[0017] Figure 3 This describes the effect of the multifunctional biodegradable composite membrane slow-release fertilizer based on sugarcane bagasse prepared in Example 1.

[0018] Figure 4 This is a scanning electron microscope image of the lignin nanoparticles prepared in Example 1.

[0019] Figure 5 This is a TEM image of the lignin nanoparticles prepared in Example 1.

[0020] Figure 6 This is a comparison chart showing the effect of different amounts of lignin nanoparticles added to the mulch film on seed germination rate in Example 1 and Comparative Examples 1 and 2. Detailed Implementation

[0021] The technical solution of the present invention will be further defined below with reference to specific embodiments, but the scope of protection is not limited to the description made.

[0022] Example 1 This invention addresses the problems of cellulose-based membranes, such as high brittleness, poor mechanical properties, and lack of multifunctional regulation. It uses lignin nanoparticles (LNPs) as reinforcing and functionalizing components to synergistically construct a multi-scale cellulose composite network structure, thereby preparing a functionalized biodegradable composite membrane with high strength, UV resistance, and slow-release properties.

[0023] This invention relates to a multifunctional biodegradable composite membrane based on sugarcane bagasse and its preparation method, the specific implementation process of which is as follows: (1) Raw material pretreatment: Select waste residue after sugarcane pressing as raw material, wash thoroughly with clean water to remove soluble sugar and impurities, dry to constant weight and then pulverize to 60 mesh for later use. This step can ensure the fineness of raw material particles and the uniformity of film formation, and control film thickness and dispersibility.

[0024] (2) Separation of cellulose and lignin by endogenous organic acid-pot method: Sugarcane bagasse powder is mixed with organic acid (4 wt%) solution such as citric acid or oxalic acid at a solid-liquid ratio of 1:10 and placed in a closed hydrothermal reactor. The mixture is reacted at 120 ℃ for 60 minutes to achieve cellulose swelling and release and lignin dissolution. After the reaction is completed, the mixture is filtered to obtain cellulose pulp and lignin-containing liquid phase.

[0025] (3) Preparation of nano-lignin particles: The lignin-containing solution was concentrated by rotary evaporation and then slowly added to deionized water under stirring conditions. The lignin molecules were induced to self-assemble into nanoparticles (LNPs) by pH and polarity changes. After freeze-drying or low-temperature concentration, the particles were used for later use. The particle size was controlled at around 200 nm.

[0026] (4) Preparation of nano-lignin-cellulose composite slurry: The cellulose slurry obtained in step (2) and the nano-lignin obtained in step (3) are compounded at a mass ratio of 3:1 to 5:1 and stirred evenly to form a stable suspension slurry. In order to impart the nutrient slow-release function, 10 wt% of micro-nano urea particles are further added (which can be uniformly dispersed by air jet milling or ultrasonic pretreatment) to construct a synergistic system of membrane-fertilizer integration.

[0027] (5) Film forming process: The above composite slurry is evenly spread on a glass plate by casting method and dried at 60°C for 24 h to obtain a preliminary film material. Finally, it is cut and packaged for later use.

[0028] Example 2 This invention addresses the problems of cellulose-based membranes, such as high brittleness, poor mechanical properties, and lack of multifunctional regulation. It uses lignin nanoparticles (LNPs) as reinforcing and functionalizing components to synergistically construct a multi-scale cellulose composite network structure, thereby preparing a functionalized biodegradable composite membrane with high strength, UV resistance, and slow-release properties.

[0029] This invention relates to a multifunctional biodegradable composite membrane based on sugarcane bagasse and its preparation method, the specific implementation process of which is as follows: (1) Raw material pretreatment: Select waste residue after sugarcane pressing as raw material, wash thoroughly with clean water to remove soluble sugar and impurities, dry to constant weight and then pulverize to 60 mesh for later use. This step can ensure the fineness of raw material particles and the uniformity of film formation, and control film thickness and dispersibility.

[0030] (2) One-pot separation of cellulose and lignin by endogenous organic acid: Sugarcane bagasse powder and oxalic acid (4 wt%) solution are mixed at a solid-liquid ratio of 1:10 and placed in a closed hydrothermal reactor. The mixture is reacted at 120°C for 60 minutes to achieve cellulose swelling and release and lignin dissolution. After the reaction is completed, the mixture is filtered to obtain cellulose pulp and lignin-containing liquid phase.

[0031] (3) Preparation of lignin nanoparticles: The lignin-containing solution was concentrated by rotary evaporation, and then slowly added dropwise to deionized water under stirring. The self-assembly of lignin molecules was induced by pH and polarity changes to form nanoparticles (LNPs). These nanoparticles were then freeze-dried or concentrated at low temperature for later use. By controlling the self-assembly conditions, well-dispersed LNPs with particle sizes of approximately 200 nm and 100 nm could be obtained, such as... Figure 4 and 5 As shown.

[0032] (4) Preparation of nano-lignin-cellulose composite slurry: The cellulose slurry obtained in step (2) and the nano-lignin obtained in step (3) are compounded at a mass ratio of 3:1 to 5:1 and stirred evenly to form a stable suspension slurry. In order to impart the nutrient slow-release function, 10 wt% of micro-nano urea particles are further added (which can be uniformly dispersed by air jet milling or ultrasonic pretreatment) to construct a synergistic system of membrane-fertilizer integration.

[0033] (5) Film forming process: The above composite slurry is evenly spread on a glass plate by casting and dried at 60°C for 24 h to obtain a preliminary film material, or a dense composite film is prepared by hot pressing (90°C, 5 MPa, maintained for 10 minutes). Finally, it is cut, packaged and ready for use.

[0034] Example 3 This invention addresses the problems of cellulose-based membranes, such as high brittleness, poor mechanical properties, and lack of multifunctional regulation. It uses lignin nanoparticles (LNPs) as reinforcing and functionalizing components to synergistically construct a multi-scale cellulose composite network structure, thereby preparing a functionalized biodegradable composite membrane with high strength, UV resistance, and slow-release properties.

[0035] This invention relates to a multifunctional biodegradable composite membrane based on sugarcane bagasse and its preparation method, the specific implementation process of which is as follows: (1) Raw material pretreatment: Select waste residue after sugarcane pressing as raw material, wash thoroughly with clean water to remove soluble sugar and impurities, dry to constant weight and then pulverize to 60 mesh for later use. This step can ensure the fineness of raw material particles and the uniformity of film formation, and control film thickness and dispersibility.

[0036] (2) One-pot separation of cellulose and lignin by endogenous organic acid: Sugarcane bagasse powder and citric acid (4 wt%) solution are mixed at a solid-liquid ratio of 1:10 and placed in a closed hydrothermal reactor. The mixture is reacted at 130 ℃ for 60 minutes to achieve cellulose swelling and release and lignin dissolution. After the reaction is completed, the mixture is filtered to obtain cellulose pulp and lignin-containing liquid phase.

[0037] (3) Preparation of nano-lignin particles: The lignin-containing solution was concentrated by rotary evaporation, and then slowly added dropwise to deionized water under stirring. The self-assembly of lignin molecules was induced by pH and polarity changes to form nanoparticles (LNPs). After freeze-drying or low-temperature concentration, they were ready for use. By controlling the self-assembly conditions, well-dispersed LNPs with a particle size of 200 nm can be obtained.

[0038] (4) Preparation of nano-lignin-cellulose composite slurry: The cellulose slurry obtained in step (2) and the nano-lignin obtained in step (3) are compounded at a mass ratio of 3:1 to 5:1 and stirred evenly to form a stable suspension slurry. In order to impart the nutrient slow-release function, 10 wt% of micro-nano urea particles are further added (which can be uniformly dispersed by air jet milling or ultrasonic pretreatment) to construct a synergistic system of membrane-fertilizer integration.

[0039] (5) Film forming process: The above composite slurry is evenly spread on a glass plate by casting and dried at 60 ℃ for 24 h to obtain a preliminary film material, or a dense composite film is prepared by hot pressing (90 ℃, 5MPa, maintained for 10 minutes). Finally, it is cut, packaged and ready for use.

[0040] Example 1 This invention addresses the problems of cellulose-based membranes, such as high brittleness, poor mechanical properties, and lack of multifunctional regulation. It uses lignin nanoparticles (LNPs) as reinforcing and functionalizing components to synergistically construct a multi-scale cellulose composite network structure, thereby preparing a functionalized biodegradable composite membrane with high strength, UV resistance, and slow-release properties.

[0041] This invention relates to a multifunctional biodegradable composite membrane based on sugarcane bagasse and its preparation method, the specific implementation process of which is as follows: (1) Raw material pretreatment: Select waste residue after sugarcane pressing as raw material, wash thoroughly with clean water to remove soluble sugar and impurities, dry to constant weight and then pulverize to 60 mesh for later use. This step can ensure the fineness of raw material particles and the uniformity of film formation, and control film thickness and dispersibility.

[0042] (2) Separation of cellulose and lignin by endogenous organic acid-pot method: Sugarcane bagasse powder is mixed with organic acid (4 wt%) solution such as citric acid or oxalic acid at a solid-liquid ratio of 1:10 and placed in a closed hydrothermal reactor. The mixture is reacted at 120 ℃ for 60 minutes to achieve cellulose swelling and release and lignin dissolution. After the reaction is completed, the mixture is filtered to obtain cellulose pulp and lignin-containing liquid phase.

[0043] (3) Preparation of nano-lignin particles: The lignin-containing solution was concentrated by rotary evaporation and then slowly added to deionized water under stirring conditions. The lignin molecules were induced to self-assemble into nanoparticles (LNPs) by pH and polarity changes. After freeze-drying or low-temperature concentration, the particles were used for later use. The particle size was controlled at around 200 nm.

[0044] (4) Preparation of nano-lignin-cellulose composite slurry: The cellulose slurry obtained in step (2) and the nano-lignin obtained in step (3) are compounded at a mass ratio of 3:1 to 5:1 and stirred evenly to form a stable suspension slurry. In order to impart the nutrient slow-release function, 10 wt% of micro-nano urea particles are further added (which can be uniformly dispersed by air jet milling or ultrasonic pretreatment) to construct a synergistic system of membrane-fertilizer integration.

[0045] (5) Film forming process: The above composite slurry is evenly spread on a glass plate by casting and dried at 60°C for 24 h to obtain a preliminary film material, or a dense composite film is prepared by hot pressing (90°C, 5MPa, maintained for 5-10 minutes). Finally, it is cut, packaged and ready for use.

[0046] Comparative Example 1 (1) Raw material pretreatment: Select waste residue after sugarcane pressing as raw material, wash thoroughly with clean water to remove soluble sugar and impurities, dry to constant weight and then pulverize to 60 mesh for later use. This step can ensure the fineness of raw material particles and the uniformity of film formation, and control film thickness and dispersibility.

[0047] (2) Strong acid method for separating bagasse cellulose and lignin: Mix bagasse powder with a strong acid (4 wt%) solution such as sulfuric acid or hydrochloric acid at a solid-liquid ratio of 1:10, place it in a closed hydrothermal reactor, and react at 120 ℃ for 60 minutes to achieve cellulose swelling and release and lignin dissolution. After the reaction is completed, filter and separate to obtain cellulose pulp and lignin-containing liquid phase.

[0048] (3) Film forming process: The above composite slurry is evenly spread on a glass plate by casting and dried at 60 ℃ for 24 h to obtain a preliminary film material, or a dense composite film is prepared by hot pressing (90 ℃, 5 MPa, maintained for 10 minutes). Finally, it is cut, packaged and ready for use.

[0049] Comparative Example 2 (1) Raw material pretreatment: Select waste residue after sugarcane pressing as raw material, wash thoroughly with clean water to remove soluble sugar and impurities, dry to constant weight and then pulverize to 60 mesh for later use. This step can ensure the fineness of raw material particles and the uniformity of film formation, and control film thickness and dispersibility.

[0050] (2) One-pot separation of cellulose and lignin by endogenous organic acid: Sugarcane bagasse powder and organic acid (4 wt%) solution such as citric acid or oxalic acid are mixed at a solid-liquid ratio of 1:10 and placed in a closed hydrothermal reactor. The mixture is reacted at 120 ℃ for 60 minutes to achieve cellulose swelling and release and lignin dissolution. After the reaction is completed, the mixture is filtered to obtain cellulose pulp and lignin-containing liquid phase.

[0051] (5) Film forming process: The above composite slurry is evenly spread on a glass plate by casting and dried at 60 ℃ for 24 h to obtain a preliminary film material, or a dense composite film is prepared by hot pressing (90 ℃, 5 MPa, maintained for 10 minutes). Finally, it is cut, packaged and ready for use.

[0052] Comparative Example 3 (1) Raw material pretreatment: Select waste residue after sugarcane pressing as raw material, wash thoroughly with clean water to remove soluble sugar and impurities, dry to constant weight and then pulverize to 60 mesh for later use. This step can ensure the fineness of raw material particles and the uniformity of film formation, and control film thickness and dispersibility.

[0053] (2) One-pot separation of cellulose and lignin by endogenous organic acids: Sugarcane bagasse powder is mixed with organic acid (4 wt%) solution such as citric acid or oxalic acid at a solid-liquid ratio of 1:10 and placed in a closed hydrothermal reactor. The mixture is reacted at 120°C for 60 minutes to achieve cellulose swelling and release and lignin dissolution. After the reaction is completed, the mixture is filtered to obtain cellulose pulp and lignin-containing liquid phase.

[0054] (3) Preparation of nano-lignin particles: The lignin-containing solution was concentrated by rotary evaporation, and then slowly added dropwise to deionized water under stirring. The self-assembly of lignin molecules was induced by pH and polarity changes to form nanoparticles (LNPs). After freeze-drying or low-temperature concentration, they were ready for use. By controlling the self-assembly conditions, well-dispersed LNPs with a particle size of 200 nm can be obtained.

[0055] (4) Film forming process: The above composite slurry is evenly spread on a glass plate by casting and dried at 60 ℃ for 24 h to obtain a preliminary film material, or a dense composite film is prepared by hot pressing (90 ℃, 5 MPa, maintained for 10 minutes). Finally, it is cut, packaged and ready for use.

[0056] Test results Example 1 shows that lignin nanoparticles prepared using the endogenous organic acid citric acid at a concentration of 4 wt% are uniform, stable, and do not aggregate. Figure 4 and Figure 5 As shown; the tensile strength of the composite-prepared film can reach 73 MPa, such as Figure 1 As shown; ultraviolet light absorption reaches its highest level, such as Figure 2 As shown; it can achieve the effect of fully slow-release fertilizer within 30 days, such as Figure 3 As shown. Figure 6 This is a comparison chart showing the effect of different amounts of lignin nanoparticles added to the mulch film on seed germination rate in Example 1 and Comparative Examples 1 and 2. The addition of lignin nanoparticles in Example 1 has a promoting effect on seed germination.

[0057] Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the technical solution of the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the content disclosed in this invention should be considered within the scope of protection of this invention.

Claims

1. A multifunctional biodegradable composite membrane based on sugarcane bagasse, characterized in that, It is prepared through the following steps: (1) Raw material pretreatment: Select the waste residue after sugarcane pressing as raw material, wash it thoroughly with clean water to remove soluble sugar and impurities, dry it to constant weight and then crush it to 60-100 mesh for later use; (2) One-pot separation of cellulose and lignin by endogenous organic acid: Sugarcane bagasse powder is mixed with organic acid solution and reacted at 120-140℃ for 30-60 minutes to achieve cellulose swelling and release and lignin dissolution. After the reaction is completed, the mixture is filtered to obtain cellulose pulp and lignin-containing liquid phase. (3) Preparation of nano-lignin particles: The lignin-containing solution is concentrated by rotary evaporation and then slowly added to deionized water under stirring. The lignin molecules are induced to self-assemble into nanoparticles by pH and polarity changes. After freeze-drying or low-temperature concentration, they are ready for use. By controlling the self-assembly conditions, LNPs with good dispersibility with particle size between 100-300 nm can be obtained. (4) Preparation of nano-lignin-cellulose composite slurry: The cellulose slurry obtained in step (2) is compounded with the nano-lignin obtained in step (3) and stirred evenly to form a stable suspension slurry; 3-10wt% of micro-nano urea particles are added to construct a synergistic system of membrane-fertilizer integration; (5) Film forming process: The above composite slurry is made into a composite film; finally, it is cut, packaged and ready for use.

2. The method for preparing a multifunctional biodegradable composite membrane based on sugarcane bagasse according to claim 1, characterized in that, The waste residue is the wet or dry residue obtained from sugarcane during the sugar or pulping process.

3. The method for preparing a multifunctional biodegradable composite membrane based on sugarcane bagasse according to claim 1, characterized in that, The organic acid is citric acid or oxalic acid.

4. The method for preparing a multifunctional biodegradable composite membrane based on sugarcane bagasse according to claim 1, characterized in that, The organic acid solution has a concentration of 3-6 wt%.

5. The method for preparing a multifunctional biodegradable composite membrane based on sugarcane bagasse according to claim 1, characterized in that, The sugarcane bagasse powder and organic acid solution are mixed at a solid-liquid ratio of 1:

10.

6. The method for preparing a multifunctional biodegradable composite membrane based on sugarcane bagasse according to claim 1, characterized in that, In step (4), the cellulose pulp obtained in step (2) is compounded with the nano-lignin obtained in step (3), specifically in a mass ratio of 3:1 to 5:

1.

7. The method for preparing a multifunctional biodegradable composite membrane based on sugarcane bagasse according to claim 1, characterized in that, The micro-nano urea particles are uniformly dispersed using airflow pulverization or ultrasonic pretreatment.

8. The method for preparing a multifunctional biodegradable composite membrane based on sugarcane bagasse according to claim 1, characterized in that, In step (5), the above composite slurry is made into a composite film. Specifically, it is spread evenly on a glass plate by casting and dried at 60°C for 24 hours to obtain a preliminary film material, or a dense composite film is prepared by hot pressing.

9. A multifunctional biodegradable composite membrane based on sugarcane bagasse, characterized in that, It is prepared by the method described in claim 1.

10. The application of the multifunctional biodegradable composite film based on sugarcane bagasse as described in claim 9 in the preparation of agricultural mulch films.

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