A complete plant biofilm, its preparation method and application

Abstract

This invention relates to the field of biomass resource utilization, specifically to a complete plant biomass membrane, its preparation method, and its application. The method involves obtaining plant biomass powder by dust removal, cleaning, drying, pulverizing, and sieving of plant biomass raw materials. The plant biomass powder is then added to a eutectic solvent, mixed thoroughly, and heated to react. After the reaction is complete, water is added to quench the reaction, and the mixture is allowed to stand at room temperature before filtration to obtain filter residue. The filter residue is spread evenly on a mold, dried, and then hot-pressed to obtain the complete plant biomass membrane. This invention solves the problem of requiring pretreatment and component separation of straw before preparing biomass membranes, enabling the high-value utilization of all components of plant biomass.

Description

Technical Field

[0001] This invention relates to the field of biomass resource utilization, specifically to a complete plant biomass membrane, its preparation method, and its application. Background Technology

[0002] As plastic waste undergoes physical, chemical, and biological degradation, it generates large amounts of secondary microplastics, further threatening human health and exacerbating environmental pollution. In this context, biodegradable and environmentally friendly packaging materials are gaining popularity.

[0003] Biomass refers to all organic matter formed through photosynthesis, including all plants, animals, and microorganisms. As a substitute for fossil fuels, biomass is attracting increasing attention due to its abundant resources and renewability. Currently, biomass products are not only diverse but also produced in huge quantities; however, their added value is low, and utilization rates are generally poor, with large amounts of surplus and expired biomass being treated as waste. If biomass resources could be utilized at a high value across all components and processed into biomass films, it would not only solve the waste of biomass resources but also address the environmental problem of "white pollution."

[0004] Current research on biomass membranes primarily utilizes straw as a raw material to prepare straw cellulose membranes. Most membrane fabrication methods only utilize cellulose or hemicellulose, requiring prior component separation of the biomass. This necessitates the use of large amounts of acidic or alkaline solutions for rinsing, easily generating secondary waste and causing unnecessary environmental damage. Therefore, there is an urgent need for a simple preparation method that eliminates the need for component separation of the biomass, allowing for the production of a complete biomass membrane. Summary of the Invention

[0005] To overcome the above problems, the present invention provides a complete plant biomass membrane, its preparation method and application.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a complete plant biofilm, comprising:

[0008] (1) Plant biomass raw materials are dusted, cleaned, dried, crushed and sieved to obtain plant biomass raw material powder;

[0009] (2) Add the plant biomass raw material powder to the eutectic solvent, mix evenly, heat to react, add water to quench the reaction after the reaction is completed, let stand at room temperature, filter to obtain the filter residue;

[0010] (3) Spread the filter residue on the mold, dry it, and then hot press it to obtain a complete plant biomass membrane.

[0011] In a second aspect, the present invention provides a complete plant biomass membrane prepared by the above-described method for preparing a complete plant biomass membrane.

[0012] A third aspect of the present invention provides the application of the above-described complete-component plant biomass film in the preparation of packaging materials.

[0013] The beneficial effects of this invention are as follows:

[0014] (1) In this invention, the reaction temperature, reaction time, and mass ratio of the eutectic solvent to the plant biomass are strictly limited. This allows the eutectic solvent to selectively dissolve some of the lignin in the plant biomass, while simultaneously loosening the cellulose in the plant biomass. The dissolved lignin is not washed away; its hydrophobicity is utilized to regenerate it in situ by adding a large amount of water as a countersolvent, forming regenerated lignin, which has an adhesive effect. During the hot pressing process, the loose cellulose and the regenerated lignin with adhesive properties become entangled together, forming a complete plant biomass membrane. This also improves the yield and mechanical properties of the complete plant biomass membrane.

[0015] (2) This invention solves the problem that straw needs to be pretreated and separated before it can be used to prepare biomass membranes, and can realize the high-value utilization of all components of plant biomass.

[0016] (3) The whole-component plant biomass film prepared by the present invention has strong tear strength and good durability compared with the biodegradable packaging materials in the prior art, thus having good application prospects.

[0017] (4) The whole-component plant biomass membrane provided by the present invention has the characteristics of wide availability of raw materials, low price and easy access, green biodegradability, short production cycle and simple process flow, and the prepared whole-component plant biomass membrane has good application prospects. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 The morphology of the complete plant biomass film obtained at different temperatures;

[0020] Figure 2 The morphology of the whole-component plant biomass film obtained under different raw material ratios;

[0021] Figure 3 The morphology of the complete plant biomass film obtained in Comparative Example 1 is shown.

[0022] Figure 4 Morphology of the complete biomass membrane obtained in Example 4. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] A first typical embodiment of the present invention provides a method for preparing a complete plant biofilm, comprising:

[0026] (1) Plant biomass raw materials are dusted, cleaned, dried, crushed and sieved to obtain plant biomass raw material powder;

[0027] (2) Add the plant biomass raw material powder to the eutectic solvent, mix evenly, heat to react, add water to quench the reaction after the reaction is completed, let stand at room temperature, filter to obtain the filter residue;

[0028] (3) Spread the filter residue on the mold, dry it, and then hot press it to obtain a complete plant biomass membrane.

[0029] In one or more embodiments, the plant biomass is a lignocellulose-based material containing cellulose, hemicellulose, and lignin.

[0030] In one or more embodiments, the particle size of the plant biomass raw material powder is 20 to 200 mesh.

[0031] In one or more embodiments, the eutectic solvent is choline chloride-lactic acid, and the molar ratio of choline chloride to lactic acid is 1:1 to 1:20.

[0032] In one or more embodiments, the mass ratio of plant biomass raw material powder to eutectic solvent is 1:1 to 1:30, preferably 1:15.

[0033] In one or more embodiments, the temperature of the heating reaction is 30–200°C, preferably 100–120°C, and the heating reaction time is 2–24 h, preferably 8–12 h.

[0034] In one or more embodiments, the mass ratio of the total mass of plant biomass raw material powder and eutectic solvent to water is 1:8 to 20, preferably 1:10.

[0035] In one or more embodiments, the standing time at room temperature is 20 to 30 hours, preferably 24 hours.

[0036] In one or more embodiments, the drying temperature is 20–110°C and the time is 2–15 h.

[0037] In one or more embodiments, the hot pressing temperature is 5–120°C, the hot pressing time is 5–60 min, and the hot pressing pressure is 500–5000 kg.

[0038] A second typical embodiment of the present invention provides a full-component plant biomass membrane prepared by the above-described method for preparing a full-component plant biomass membrane.

[0039] A third typical embodiment of the present invention provides the application of the above-mentioned full-component plant biomass film in the preparation of packaging materials.

[0040] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0041] Preparation of eutectic solvent: Take choline chloride and lactic acid in a molar ratio of 1:10, mix and stir at 80°C for 2 hours, and a homogeneous transparent liquid phase is obtained, which is the choline chloride-lactic acid eutectic solvent.

[0042] The formula for the film-forming yield of the complete plant biomass film prepared in the following examples and Comparative Example 1 is as follows:

[0043]

[0044] Example 1

[0045] Poplar sawdust was removed, cleaned, dried, pulverized, and sieved to obtain poplar powder with a particle size of 80 mesh. The poplar powder was mixed evenly with a choline chloride-lactic acid eutectic solvent at a mass ratio of 1:15. The mixture was stirred and reacted at 60℃, 90℃, 100℃, 110℃, 120℃, and 130℃ for 12 hours respectively. After the reaction was completed, water was added to quench the reaction (the mass ratio of the choline chloride-lactic acid eutectic solvent to deionized water was 1:10). The mixture was allowed to stand at room temperature for 24 hours, and the residue was filtered. The residue was spread evenly in a polytetrafluoroethylene mold and dried in an oven at 60℃ for 12 hours. Then, it was extruded into a film using a hot press at 60℃ for 10 minutes and a pressure of 2000 kg.

[0046] In this embodiment, the morphology of the complete plant biomass film obtained at different temperatures is as follows: Figure 1 As shown in Table 1, the film-forming yields of the complete plant biomass films obtained at different temperatures in this embodiment are shown in Table 1.

[0047] Table 1. Film-forming yield of whole-component plant biomass films obtained at different temperatures.

[0048]

[0049] from Figure 1 As shown in Table 1, when poplar wood powder is treated with a choline chloride-lactic acid eutectic solvent at different temperatures, the degree of reaction gradually increases with increasing temperature. After adding deionized water, stirring, and allowing it to stand, obvious stratification occurs (indicating lignin precipitation). The filtrate color also varies after filtration. The yield of the residue first decreases and then increases with increasing temperature, and the residue color gradually changes from light brown to black. It can form a film and gradually becomes finer. Therefore, the optimal reaction temperature for the choline chloride-lactic acid eutectic solvent with plant biomass powder is 100–120℃.

[0050] Example 2

[0051] Corn stalks were dusted, cleaned, dried, crushed, and sieved to obtain 80-mesh stalk powder. The stalk powder was mixed with a choline chloride-lactic acid eutectic solvent at mass ratios of 1:8, 1:10, 1:13, 1:15, and 1:17, respectively, and stirred at 110℃ for 12 hours. After the reaction was complete, water was added to quench the reaction (the mass ratio of the choline chloride-lactic acid eutectic solvent to deionized water was 1:10). The mixture was allowed to stand at room temperature for 24 hours, and the residue was filtered. The residue was spread evenly in a polytetrafluoroethylene mold and dried in an oven at 60℃ for 12 hours. Then, it was extruded into a film using a hot press at 60℃ for 10 minutes and a pressure of 2000 kg.

[0052] In this embodiment, the morphology of the complete plant biomass film obtained under different raw material ratios is as follows: Figure 2 As shown in Table 2, the film-forming yields of the complete plant biomass films obtained under different raw material ratios in this embodiment are shown in Table 2.

[0053] Table 2. Film-forming yield of complete plant biomass films obtained under different raw material ratios.

[0054]

[0055] from Figure 2As shown in Table 2, when straw powder is treated with choline chloride-lactic acid eutectic solvent at different mass ratios, the degree of reaction gradually increases with the increase of the mass of the choline chloride-lactic acid eutectic solvent. After adding deionized water, stirring, and standing, there is obvious stratification (indicating lignin precipitation). After filtration, the color of the filtrate gradually darkens, and the color of the residue gradually changes from light brown to black. The surface roughness of the film varies depending on the degree of film laying, drying, and demolding. The reaction effect is better when the mass ratio is 1:15, the residue has less noticeable particle texture after film laying, and it is easy to demold after drying.

[0056] Example 3

[0057] Wheat straw was dusted, cleaned, dried, crushed, and sieved to obtain wheat straw powder with a particle size of 80 mesh. The wheat straw was mixed with a choline chloride-lactic acid eutectic solvent at a mass ratio of 1:15 and stirred at 110℃ for 8 h, 10 h, and 12 h, respectively. After the reaction was complete, water was added to quench the reaction (the mass ratio of the choline chloride-lactic acid eutectic solvent to deionized water was 1:10). The mixture was allowed to stand at room temperature for 24 h, filtered to obtain the filter residue, and then spread evenly in a polytetrafluoroethylene mold. After drying in an oven at 60℃ for 12 h, the residue was extruded into a film using a hot press at 60℃ for 10 min and a pressure of 2000 kg.

[0058] The film-forming yields of the complete plant biomass films obtained at different reaction times in this embodiment are shown in Table 3.

[0059] Table 3. Film-forming yield of the complete plant biomass film obtained at different reaction times.

[0060]

[0061] As can be seen from Table 3, when wheat straw powder is treated with choline chloride-lactic acid eutectic solvent, the color change at the end is not significant as the reaction time increases. After adding deionized water, stirring, and standing, there is obvious stratification (indicating lignin precipitation). After filtration, the color of the filtrate and filter residue gradually deepens over time. It can form a film and gradually changes from rough to fine. The film is easy to demold after drying.

[0062] Comparative Example 1

[0063] Preparation of eutectic solvent: Choline chloride and oxalic acid were mixed and stirred at 80°C for 2 hours in a molar ratio of 1:1 to obtain a homogeneous and transparent liquid phase, which is the choline chloride-oxalic acid eutectic solvent.

[0064] Poplar sawdust was removed, cleaned, dried, pulverized, and sieved to obtain poplar powder with a particle size of 80 mesh. The poplar powder was mixed evenly with a choline chloride-lactic acid eutectic solvent at a mass ratio of 1:15 and stirred at 110℃ for 12 hours. After the reaction was complete, water was added to quench the reaction (the mass ratio of the choline chloride-lactic acid eutectic solvent to deionized water was 1:10). The mixture was allowed to stand at room temperature for 24 hours, and the residue was filtered. The residue was spread evenly in a polytetrafluoroethylene mold and dried in an oven at 60℃ for 12 hours. Then, it was extruded into a film using a hot press at 60℃ for 10 minutes and a pressure of 2000 kg. The morphology of the complete plant biomass film obtained in this comparative example is shown below. Figure 3 As shown.

[0065] The results showed that when poplar powder was treated with a choline chloride-oxalic acid eutectic solvent, the system reacted vigorously, exhibiting expansion and turning black at the end. After adding deionized water and stirring, no obvious stratification was observed after standing. The filtrate was light yellow, the residue was fine and black, and the film formed was fine but brittle and difficult to demold.

[0066] Example 4

[0067] Hemp stalks were dusted, cleaned, dried, crushed, and sieved to obtain hemp stalk powder with a particle size of 80 mesh. The hemp stalk powder was mixed evenly with a choline chloride-lactic acid eutectic solvent at a mass ratio of 1:15 and stirred at 110°C for 12 hours. After the reaction was complete, water was added to quench the reaction (the mass ratio of the choline chloride-lactic acid eutectic solvent to deionized water was 1:10). The mixture was allowed to stand at room temperature for 24 hours, and the residue was filtered. The residue was spread evenly in a polytetrafluoroethylene mold and dried in an oven at 60°C for 12 hours. Then, it was extruded into a film using a hot press at 60°C for 10 minutes and a pressure of 2000 kg. The morphology of the complete biomass film obtained in this example is as follows. Figure 4 As shown.

[0068] Hemp stalk powder was treated with a choline chloride-lactic acid eutectic solvent. The system turned dark brown upon completion of the reaction. After adding deionized water and stirring, and allowing it to stand, obvious stratification was observed (indicating lignin precipitation). The filtrate after filtration was yellow, with very few brown residue particles, indicating a complete reaction. The resulting film was easy to demold after drying and formed well, with a light-colored film and a residue yield of 96.85%. The extruded biomass film had a whiteness of 3.92% and a density of 1.24 g / m³. 3 The elongation is 43.75% and the tear strength is 1.2 N / 25 μm.

[0069] The performance of the full-component plant biomass membrane obtained in this embodiment compared with that of membrane materials in the prior art is shown in Table 4.

[0070] Table 4. Performance of different biodegradable membrane materials

[0071]

[0072] As can be seen from Table 4, the density and tear strength of the all-component plant biomass film prepared in this embodiment are significantly higher than the hardness of ordinary plastic films; its elongation is better than PT film, comparable to PA film, lower than PVDC film, and significantly lower than CPP film. In addition, the hot-pressed product film is dark in color with a certain degree of whiteness, has no obvious liquid absorption properties, and its degradability is outstanding compared with plastic films.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a complete plant biofilm, characterized in that, include: (1) Plant biomass raw materials are dusted, cleaned, dried, crushed and sieved to obtain plant biomass raw material powder; (2) Add the plant biomass raw material powder to the eutectic solvent, mix evenly, heat to react, add water to quench the reaction after the reaction is completed, let stand at room temperature, filter to obtain the filter residue; the eutectic solvent is choline chloride-lactic acid, the molar ratio of choline chloride to lactic acid is 1:10; the mass ratio of the plant biomass raw material powder to the eutectic solvent is 1:15; the heating reaction temperature is 100~120 ℃, and the heating reaction time is 8~12 h; (3) Spread the filter residue on the mold, dry it, and then hot press it to obtain a complete plant biomass membrane.

2. The method for preparing a complete plant biofilm as described in claim 1, characterized in that, The plant biomass is a lignocellulose-based material containing cellulose, hemicellulose, and lignin.

3. The method for preparing a complete plant biofilm as described in claim 1, characterized in that, The drying temperature is 20~110℃ and the time is 2~15 h.

4. The method for preparing a complete plant biofilm as described in claim 1, characterized in that, The hot pressing temperature is 5~120 ℃, the hot pressing time is 5~60 min, and the hot pressing pressure is 500~5000 Kg.

5. The whole-component plant biomass membrane prepared by the method of any one of claims 1 to 4.

6. The application of the complete plant biomass film according to claim 5 in the preparation of packaging materials.

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