Algal-based biodegradable packaging material with adjustable hydrophilicity and hydrophobicity and its preparation and application

Abstract

This invention discloses a hydrophobic-adjustable seaweed-based biodegradable packaging material, its preparation method, and its application. The preparation method of the hydrophobic-adjustable seaweed-based biodegradable packaging material includes providing a first mixed system comprising seaweed polysaccharides, water, and a crosslinking agent; heating and stirring to generate a seaweed polysaccharide solution; adding a solid filler to the seaweed polysaccharide solution to uniformly disperse the solid filler into two-dimensional nanosheets, forming a second mixed system; processing and shaping the second mixed system to obtain the seaweed-based biodegradable packaging material; and applying a hydrophobic modifier to the surface of the seaweed-based biodegradable packaging material to change the material surface from hydrophilic to hydrophobic. This invention uses seaweed polysaccharides as the main raw material, reducing the pressure on petroleum fossil resources, making the preparation process green and environmentally friendly, and the prepared seaweed-based biodegradable packaging material has excellent mechanical and barrier properties, and can achieve complete degradation in natural soil environments.

Description

Technical Field

[0001] This invention belongs to the field of biodegradable materials technology, specifically relating to a seaweed-based biodegradable packaging material with adjustable hydrophilicity and hydrophobicity, its preparation method and application. Background Technology

[0002] Plastics dominate the food packaging industry due to their light weight, low cost, and high processability. However, most plastics currently in use are derived from petrochemical products, which are difficult to degrade in nature, ultimately becoming "white pollution" and posing a serious threat to the ecological environment. Furthermore, petroleum-based plastics release microplastics during daily use and their degradation process over hundreds of years, affecting human and animal health.

[0003] Biopolymers, as biodegradable materials obtainable from renewable resources, hold promise as a potential replacement for synthetic polymers as new plastic raw materials in the future. Currently, polylactic acid (PLA), derived from crops such as corn and potatoes, has become the most widely researched and maturely applied novel biodegradable plastic both domestically and internationally. However, PLA suffers from a low glass transition temperature, poor ductility, high cost, and can only decompose under relatively harsh industrial composting conditions. Therefore, developing low-cost food-grade packaging materials that combine excellent mechanical properties with biodegradability remains a significant challenge.

[0004] The ocean is a huge "blue granary," and seaweed, as an important component of marine resources, is widely distributed in major sea areas and has very abundant reserves. The main characteristics of seaweed are as follows: (1) Seaweed grows rapidly, at a rate of about 60 cm per day, and is a green and renewable natural resource; (2) Seaweed growth only requires seawater and sunlight, resulting in low cultivation costs and avoiding the problems of excessive pesticide residues and antibiotics faced by terrestrial crops; (3) Seaweed has excellent carbon fixation capabilities; (4) Seaweed is rich in active polysaccharide components such as alginate, agar, and cellulose, which have excellent antioxidant, antibacterial, antiviral, and film-forming properties, and its three-dimensional structure is very stable. These characteristics give seaweed great potential for the production of low-cost, green, environmentally friendly, and biodegradable materials. However, most of the active polysaccharide components of seaweed are hydrophilic, which makes it impossible for seaweed-based packaging products to meet the actual production applications in multiple scenarios. On the other hand, the mechanical properties of seaweed-based biodegradable materials still need to be improved compared to traditional petroleum-based plastics. Summary of the Invention

[0005] The main objective of this invention is to provide a seaweed-based biodegradable packaging material with adjustable hydrophilicity and hydrophobicity, as well as its preparation method and application, to overcome the shortcomings of the prior art.

[0006] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0007] This invention provides a method for preparing a seaweed-based biodegradable packaging material with adjustable hydrophobicity and hydrophobicity, comprising:

[0008] A first mixture containing seaweed polysaccharides, water, and a cross-linking agent is provided, and the mixture is heated and stirred to generate a seaweed polysaccharide solution.

[0009] Solid filler was added to the seaweed polysaccharide solution to uniformly disperse the solid filler into two-dimensional nanosheets with a diameter of 1~10μm and a thickness of 5~30nm in the seaweed polysaccharide solution, forming a second mixing system. The second mixing system was then processed and shaped to obtain seaweed-based biodegradable packaging material.

[0010] A hydrophobic modifier is applied to the surface of the seaweed-based biodegradable packaging material and dried at room temperature to change the surface of the material from hydrophilic to hydrophobic, thereby obtaining a seaweed-based biodegradable packaging material with adjustable hydrophilicity and hydrophobicity.

[0011] Furthermore, in the first mixed system, the mass percentage of seaweed polysaccharide is 1% to 10%, and the mass percentage of cross-linking agent is 0.5% to 2.5%.

[0012] Furthermore, the mass percentage of solid filler in the second mixture system is 0.1% to 5%.

[0013] Furthermore, the heating temperature of the first mixing system is 45~70℃, the heating time is 30~240min, and the stirring speed is 550~1000rpm.

[0014] Furthermore, the solid filler is uniformly dispersed in the seaweed polysaccharide solution for 2-5 hours.

[0015] Furthermore, the seaweed polysaccharide includes at least one of the following from red algae, brown algae, and green algae: seaweed cellulose, carrageenan, xylan, mannan, sodium alginate, and agar.

[0016] Furthermore, the crosslinking agent includes any one or a combination of two or more of glycolic acid, lactic acid, mandelic acid, malic acid, phytic acid, tartaric acid, gluconic acid, gallic acid, tannic acid, tannic acid, citric acid, hyaluronic acid, gum arabic, dopamine, starch, gelatin, chitosan, D-panthenol, polyvinyl alcohol, polyethylene glycol, polylactic acid, boric acid, and glycerin.

[0017] Furthermore, the solid filler includes inorganic fillers and / or organic fillers.

[0018] Furthermore, the hydrophobic modifier is composed of an acidic solution, ethanol, and a low surface energy modifier, wherein the acidic solution includes any one of hydrochloric acid, sulfuric acid, nitric acid, and acetic acid solutions; and the low surface energy modifier includes any one or a combination of two or more of the following: triethoxysilane, tetraethoxysilane, n-octyltrimethoxysilane, dodecylmethyldimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, n-octadecyltriethoxysilane, perfluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, and perfluorooctyltriethoxysilane.

[0019] Furthermore, the volume ratio of the acidic solution, the low surface energy modifier, and ethanol is (1~3):(3~6):(6~10).

[0020] Furthermore, the concentration of the acidic solution is 0.005~0.02 mol / L, and the concentration of the low surface energy modifier is 10~20 mmol / L.

[0021] This invention also provides a hydrophobic-sensitive, tunable-hydrophobic seaweed-based biodegradable packaging material prepared by the aforementioned method. The hydrophobic-sensitive, tunable-hydrophobic seaweed-based biodegradable packaging material has a tensile strength of 25.89~80.32 MPa and a Young's modulus of 1.23~3.16 GPa, a maximum contact angle of 132°, and minimum ultraviolet, oxygen, and water vapor transmittances of 2%, 15.08 cc m, and 15.08 cc m, respectively. -2 day -1 bar -1 and 20 g m -2 day -1 It takes 7 to 85 days to completely degrade in the natural environment.

[0022] The present invention also provides the application of the aforementioned hydrophobic-hydrophobic tunable seaweed-based biodegradable packaging material in the field of food packaging.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention uses green and renewable seaweed polysaccharide as the main raw material. The crosslinking agent and solid filler used are mostly derived from natural plants, which reduces the pressure of petroleum fossil resources. At the same time, the entire processing and preparation process is green and environmentally friendly. The full utilization of seaweed resources helps to effectively fix carbon and thus reduce greenhouse gases. The seaweed-based packaging material prepared by the present invention has excellent mechanical strength and ultraviolet and oxygen barrier properties, and can be rapidly degraded in natural environment.

[0025] (2) The seaweed polysaccharide structure of this invention contains abundant hydroxyl groups, which react with Ca contained in some of the fillers. 2+ Cu2+ By coordinating with metal ions or boric acid groups, seaweed-based packaging materials can be transformed into water-insoluble materials. Furthermore, low-surface-energy silane-based hydrophobic modifiers can be grafted onto the surface of seaweed-based packaging materials using simple spraying or brushing methods, transforming the surface into a hydrophobic state and improving its water barrier properties. In addition, the resulting biodegradable seaweed-based packaging materials, with adjustable hydrophilicity and hydrophobicity and excellent mechanical properties, can meet diverse application scenarios in the food packaging field (such as: lunch boxes, straws, condiment bags, coffee bags, food storage bags, shopping bags, water cups, etc.). Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a photograph of the transparent seaweed-based packaging film material obtained in Example 1 of the present invention.

[0028] Figure 2 This is a photograph of a shopping bag made from the transparent seaweed-based packaging film material obtained in Example 1 of the present invention.

[0029] Figure 3 This is a photograph of the seaweed-based packaging material obtained in Example 1 of the present invention processed into a condiment packaging bag.

[0030] Figure 4 This is a photograph illustrating the water solubility of the seaweed-based seasoning packaging bag obtained in Example 1 of the present invention.

[0031] Figure 5 This is a photograph showing the load-bearing capacity of the seaweed-based packaging material obtained in Embodiment 2 of the present invention.

[0032] Figure 6 This is a photograph showing the processing of the seaweed-based packaging material obtained in Example 3 of the present invention into a fruit and vegetable preservation bag.

[0033] Figure 7 This is a stress-strain curve of the seaweed-based packaging material obtained in Example 4 of the present invention.

[0034] Figure 8 A photograph of a straw made from the hydrophobic seaweed-based packaging material obtained in Example 6 of this invention after being soaked in an aqueous solution for 2 hours. Detailed Implementation

[0035] In view of the deficiencies of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. This invention uses natural and renewable plant resources as the main raw materials and has the advantages of simple operation, economy and environmental protection, and easy degradation. At the same time, by filling with various solid fillers, the mechanical strength and stability of the material can be further enhanced.

[0036] One aspect of this invention provides a method for preparing a seaweed-based biodegradable packaging material with adjustable hydrophilicity and hydrophobicity, comprising:

[0037] A first mixture containing seaweed polysaccharides, water, and a cross-linking agent is provided, and the mixture is heated and stirred to generate a seaweed polysaccharide solution.

[0038] Solid filler was added to the seaweed polysaccharide solution to uniformly disperse the solid filler into two-dimensional nanosheets with a diameter of 1~10μm and a thickness of 5~30nm in the seaweed polysaccharide solution, forming a second mixing system. The second mixing system was then processed and shaped to obtain seaweed-based biodegradable packaging material.

[0039] A hydrophobic modifier is applied to the surface of the seaweed-based biodegradable packaging material and dried at room temperature to change the surface of the material from hydrophilic to hydrophobic, thereby obtaining a seaweed-based biodegradable packaging material with adjustable hydrophilicity and hydrophobicity.

[0040] In some preferred embodiments, the mass percentage of seaweed polysaccharide in the first mixture is 1% to 10%, and the mass percentage of crosslinking agent is 0.5% to 2.5%.

[0041] In some preferred embodiments, the mass percentage of solid filler in the second mixture is 0.1% to 5%.

[0042] In some preferred embodiments, the heating temperature of the first mixing system is 45~70℃, the heating time is 30~240min, and the stirring speed is 550~1000rpm.

[0043] In some preferred embodiments, the solid filler is uniformly dispersed in the seaweed polysaccharide solution for 2-5 hours.

[0044] In some preferred embodiments, the processing includes: uniformly spreading the second mixture system on a plastic petri dish using a solution casting method or a scraping method, and placing it at 35~60℃ and 40~70RH% for 24~120h to obtain seaweed-based biodegradable packaging material.

[0045] In some preferred embodiments, the processing includes: using a polymer material molding process to directly obtain seaweed-based biodegradable packaging material.

[0046] In some more preferred embodiments, the polymer material molding and processing technology may include any one of injection molding, compression molding, calendering, casting molding, etc., but is not limited to this.

[0047] In some preferred embodiments, the seaweed polysaccharide may include at least one of seaweed cellulose, carrageenan, xylan, mannan, sodium alginate, agar, etc. from red algae, brown algae, and green algae, but is not limited thereto.

[0048] In some preferred embodiments, the crosslinking agent may include any one or a combination of two or more of glycolic acid, lactic acid, mandelic acid, malic acid, phytic acid, tartaric acid, gluconic acid, gallic acid, tannic acid, tannic acid, citric acid, hyaluronic acid, gum arabic, dopamine, starch, gelatin, chitosan, D-panthenol, polyvinyl alcohol, polyethylene glycol, polylactic acid, boric acid, glycerin, etc., but is not limited thereto.

[0049] In some preferred embodiments, the solid filler includes inorganic fillers and / or organic fillers.

[0050] In some more preferred embodiments, the inorganic filler may include at least one of boron nitride, phlogopite, graphene, graphene oxide, nano-calcium carbonate, kaolin, porous quartz powder, glass microspheres, barium sulfate, etc., but is not limited thereto.

[0051] In some more preferred embodiments, the organic filler may include any one or a combination of two or more of the following: natural fibers, metal-organic covalent frameworks containing various metal ions, and various covalent organic frameworks, but is not limited thereto.

[0052] In some more preferred embodiments, the natural fiber is derived from the crushed products of various plants such as wood, straw, fruit shells, seaweed, and seagrass, including but not limited to at least one of wood flour, paper flour, wheat straw, walnut shells, peanut shells, cotton, flax, rice straw, and sugarcane bagasse.

[0053] In some more preferred embodiments, the metal-organic covalent framework containing various metal ions mainly includes, but is not limited to, any one of ZIF-7, ZIF-8, MOF-801, UIO-66, Zr-NMOFs, PCN-61, PCN-66, MOF-5, MOF-74, MAF-6, etc.

[0054] In some more preferred embodiments, the various covalent organic frameworks include, but are not limited to, any one of the following: borate COF-1 and COF-5, imine COF-300, triazine CTF-1, phthalocyanine NiPc-COF, porphyrin H2P-COF, CuP-COF, Znp-COF, etc.

[0055] In some preferred embodiments, the hydrophobic modifier is composed of an acidic solution, ethanol, and a low surface energy modifier. The acidic solution may include, but is not limited to, any one of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, etc. The low surface energy modifier may include, but is not limited to, any one or a combination of two or more of the following: triethoxysilane, tetraethoxysilane, n-octyltrimethoxysilane, dodecylmethyldimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, n-octadecyltriethoxysilane, perfluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, perfluorooctyltriethoxysilane, etc.

[0056] In some more preferred embodiments, the volume ratio of the acidic solution, the low surface energy modifier, and ethanol is (1~3):(3~6):(6~10).

[0057] In some more preferred embodiments, the concentration of the acidic solution is 0.005~0.02 mol / L, and the concentration of the low surface energy modifier is 10~20 mmol / L.

[0058] Another aspect of this invention provides a hydrophobic-sensitive tunable seaweed-based biodegradable packaging material prepared by the aforementioned method. The hydrophobic-sensitive tunable seaweed-based biodegradable packaging material has a tensile strength of 25.89~80.32 MPa and a Young's modulus of 1.23~3.16 GPa, a maximum contact angle of 132°, and minimum ultraviolet, oxygen, and water vapor transmittances of 2%, 15.08 cc m, and 15.08 cc m, respectively. -2 day -1 bar -1 and 20 g m -2 day -1 It takes 7 to 85 days to completely degrade in the natural environment.

[0059] Another aspect of the present invention provides the application of the aforementioned hydrophobic-hydrophobic tunable seaweed-based biodegradable packaging material in the field of food packaging.

[0060] This invention utilizes the abundant hydroxyl groups in seaweed polysaccharides and the Ca contained in a portion of the filler. 2+ Cu 2+ The coordination of metal ions or boric acid groups can transform seaweed-based packaging materials into water-insoluble materials. Furthermore, hydrophobic segments with silane end caps can be grafted onto the material surface through simple spraying or brushing methods, thereby improving the material's water barrier properties and meeting the needs of various practical applications, from straws and water cups to packaging bags, food storage bags, shopping bags, and seasoning bags.

[0061] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0062] The tensile properties of the samples in the following examples were tested using an Instron universal testing machine. The sample size was 95×10mm, the clamping distance was 50mm, and the tensile speed was 10mm / min. Before testing, the thickness of the sample was measured using an electronic digital display outside micrometer (two-button). Three data points were collected for each sample, and the average thickness value was calculated. After entering the testing interface, the computer continuously collected and analyzed various test data, plotted the test curves in real time, automatically calculated various test parameters and output reports. After the sample fractured, the strength and elongation values ​​were recorded, and the Young's modulus of the sample was calculated based on the stress-strain curve.

[0063] Example 1

[0064] 0.2g of sodium alginate and 0.1g of gelatin were weighed and added to a beaker containing 20mL of deionized water. The mixture was heated in an oil bath at 45℃ for 30 minutes with a stirring speed of 550rpm. After the sodium alginate and gelatin were completely dissolved, 0.02g of edible phlogopite powder was added as a filler. The mixture was stirred for 2 hours using a top-mounted stirrer to uniformly disperse the phlogopite powder in the sodium alginate solution as two-dimensional nanosheets. Further, the sodium alginate solution filled with the filler was evenly spread on a plastic petri dish and placed at 35℃ and 45% RH for 24 hours to obtain a seaweed-based packaging material. The material exhibited a tensile strength of 33.76MPa and a Young's modulus of 1.23GPa, and transmittances of 8% for ultraviolet light and 18.21 cc m for oxygen. -2 day -1 bar -1 It can be completely degraded in natural soil within 7 days. Figure 1 , 2 The images show the seaweed-based film material and its processing into shopping bags. Figure 3 The exhibition showcases condiment packaging bags obtained through further processing of the materials. For example... Figure 4 As shown, due to the inherent hydrophilicity of seaweed polysaccharides, and the green and non-toxic nature of sodium alginate, gelatin, and edible phlogopite powder, they can be placed in water or other foods along with the seaweed-based packaging bag. The seaweed-based packaging bag can dissolve quickly and does not cause harm to the human body, thus avoiding the "white pollution" caused to the ecological environment by petroleum-based condiment packaging bags.

[0065] Example 2

[0066] Weigh 1g of seaweed cellulose and 0.3g of glycerol, add them to a beaker containing 20mL of deionized water, and heat in an oil bath for 30min at 55℃ with a stirring speed of 550rpm. After the seaweed cellulose and glycerol are completely dissolved, add 0.5g of edible phlogopite powder as a filler, and stir with a top-mounted stirrer for 4h to uniformly disperse the phlogopite powder in the seaweed cellulose solution in the form of two-dimensional nanosheets. Further, spread the filler-filled seaweed cellulose solution evenly on a plastic petri dish and place it at 45℃ and 45% RH for 24h to obtain seaweed-based packaging material. The material has a tensile strength of 45MPa and a Young's modulus of 1.56GPa, and transmittances of 4% for ultraviolet light and 15.08 cc m for oxygen. -2 day -1 bar -1 It can completely degrade in natural soil within 7 days. For example... Figure 5 As shown, a sample measuring 5 cm in length and 1 cm in width can withstand a weight of 5 kg.

[0067] Example 3

[0068] Weigh 6g of sodium alginate and 1.5g of glycerol, and add them to a beaker containing 300mL of deionized water. Heat in an oil bath for 30 minutes at 60℃ with a stirring speed of 550rpm. After the sodium alginate and glycerol are completely dissolved, add 3g of edible phlogopite powder as a filler and stir for 2 hours using a top-mounted stirrer to uniformly disperse the phlogopite powder in the sodium alginate solution as two-dimensional nanosheets. Spread the sodium alginate solution filled with the filler evenly on a plastic petri dish and place it at 35℃ and 45% RH for 24 hours to obtain the seaweed-based packaging material. The material has a tensile strength of 41.2MPa and a Young's modulus of 1.33GPa, and its transmittance for ultraviolet light and oxygen is 5.2% and 15.69cc m, respectively. -2 day -1 bar -1 It can completely degrade in natural soil within 7 days. For example... Figure 6 As shown, seaweed packaging materials can be further processed into fruit and vegetable packaging bags. Due to their excellent ability to block ultraviolet rays and oxygen, seaweed-based fruit and vegetable packaging bags can preserve food that is prone to spoilage.

[0069] Example 4

[0070] Weigh 2g of agar and 0.5g of hyaluronic acid, add them to a beaker containing 20mL of deionized water, and heat in an oil bath for 30 minutes at 65℃ with a stirring speed of 550rpm. After the agar and hyaluronic acid are completely dissolved, add 1g of nano-calcium carbonate as a filler, and stir with a top-mounted stirrer for 5 hours to ensure uniform dispersion of the nano-calcium carbonate. Further, evenly spread the agar solution containing the filler on a plastic petri dish and place it at 60℃ and 45% RH for 24 hours to obtain the seaweed-based packaging material. The stress-strain curve is shown below. Figure 7 As shown, its fracture strength and Young's modulus are 56.21 MPa and 2.24 GPa, respectively, and its transmittance for ultraviolet light and oxygen is 6% and 16.25 cc m, respectively. -2 day -1 bar -1 It can be completely degraded in natural soil within 10 days.

[0071] Furthermore, since agar contains abundant hydroxyl groups, which can coordinate with calcium ions in nano-calcium carbonate, the addition of nano-calcium carbonate can transform hydrophilic materials into water-insoluble materials. When the materials are buried in the soil, they can be transformed back into water-soluble materials through ion exchange, and then decomposed by soil microorganisms.

[0072] Example 5

[0073] Weigh 0.8g of seaweed cellulose and 0.25g of boric acid, add them to a beaker containing 20mL of deionized water, and heat in an oil bath for 60min at 60℃ with a stirring speed of 550rpm. After the seaweed cellulose and boric acid are completely dissolved, add 0.05g of metal-organic framework particles PCN-66 as a filler, and stir with a top-mounted stirrer for 2h to ensure uniform dispersion of PCN-66. Further, evenly spread the seaweed cellulose solution filled with the filler on a plastic petri dish and place it at 45℃ and 45% RH for 24h to obtain seaweed-based packaging material. The material has a tensile strength of 25.89MPa and a Young's modulus of 1.03GPa, and transmittances of 5% for ultraviolet light and 19.36 cc m for oxygen, respectively. -2 day -1 bar -1 It can be fully degraded in natural soil within 30 days.

[0074] In addition, since seaweed cellulose contains abundant hydroxyl groups, it can coordinate with copper ions in the metal-organic framework PCN-66, thereby transforming the hydrophilic material into a water-insoluble material. When the material is buried in the soil, it can be transformed back into a water-soluble material through ion exchange and decomposed by soil microorganisms.

[0075] Example 6

[0076] Weigh 6g of sodium alginate and 1.5g of glycerol, and add them to a beaker containing 300mL of deionized water. Heat in an oil bath for 30 minutes at 70℃, stirring at 550rpm. After the sodium alginate and glycerol are completely dissolved, add 3g of edible phlogopite powder as a filler. Stir with a top-mounted mixer for 2 hours to uniformly disperse the phlogopite powder in the sodium alginate solution as two-dimensional nanosheets. Spread the sodium alginate solution filled with the filler evenly on a plastic petri dish and place it at 35℃ and 45% RH for 24 hours to obtain the seaweed-based packaging material.

[0077] Further, 8 mL of ethanol, 1 mL of 0.01 M hydrochloric acid, 2.7 mL of tetramethoxysilane, and 0.67 mL of octadecyltrimethoxysilane were dissolved together in a 20 mL glass sample bottle to prepare a hydrophobic modifier. The hydrophobic modifier was then uniformly brushed onto the surface of the packaging material and dried at room temperature to obtain a seaweed-based packaging material with a hydrophobic surface and a contact angle of 120°. Due to its low surface energy, it exhibits good water barrier properties (water vapor permeability is 48 g m). -2 day -1 ). Figure 8 The image shows a straw made of hydrophobic seaweed-based material after being soaked in an aqueous solution for 2 hours; its structure and function remain almost completely intact. The material has a tensile strength of 36 MPa and a Young's modulus of 1.26 GPa, and its transmittance for ultraviolet light and oxygen is 7.8% and 18.56 cc m, respectively. -2 day -1 bar -1 It can be completely degraded in natural soil within 18 days.

[0078] Example 7

[0079] Weigh 1g of agar and 0.3g of glycerol, and add them to a beaker containing 20mL of deionized water. Heat in an oil bath for 240 minutes at 55℃ with a stirring speed of 550rpm. After the agar and glycerol are completely dissolved, add 0.5g of paper powder as a filler and stir with a top-mounted mixer for 2 hours to ensure uniform dispersion of the paper powder. Further, evenly spread the agar solution containing the filler onto a plastic petri dish and incubate at 45℃ and 45% RH for 24 hours to obtain the seaweed-based packaging material.

[0080] Further, 8 mL of ethanol, 1 mL of 0.02 M hydrochloric acid, 2 mL of trimethoxysilane, and 0.5 mL of perfluorodecyltrimethoxysilane were dissolved together in a 20 mL glass sample vial to prepare a hydrophobic modifier. The hydrophobic modifier was then uniformly brushed onto the material surface and dried at room temperature to obtain a seaweed-based packaging material with a hydrophobic surface and a contact angle of 126°. Due to its low surface energy, it exhibits good water barrier properties (water vapor permeability is 29 g m³ / s). -2 day -1 The material has a fracture strength of 65.34 MPa and a Young's modulus of 2.89 GPa, and its transmittance for ultraviolet light and oxygen is 3.5% and 18.56 cc m, respectively. -2 day -1 bar -1 It can be completely degraded in natural soil within 60 days.

[0081] Example 8

[0082] Weigh 1g of sodium alginate and 0.3g of glycerol, and add them to a beaker containing 20mL of deionized water. Heat in an oil bath for 30 minutes at 55℃ with a stirring speed of 550rpm. After the sodium alginate and glycerol are completely dissolved, add 0.6g of wood flour and 0.15g of nano-calcium carbonate as fillers, and stir with a top-mounted stirrer for 4 hours to ensure uniform dispersion of the wood flour and nano-calcium carbonate. Further, evenly spread the sodium alginate solution containing the fillers onto a plastic petri dish and place it at 45℃ and 45% RH for 24 hours to obtain the seaweed-based packaging material.

[0083] Further, 8 mL of ethanol, 1 mL of 0.01 M hydrochloric acid, 2 mL of trimethoxysilane, and 0.5 mL of perfluorodecyltriethoxysilane were dissolved together in a 20 mL glass sample bottle to prepare a hydrophobic modifier. The hydrophobic modifier was then uniformly brushed onto the material surface and dried at room temperature to obtain a seaweed-based packaging material with a hydrophobic surface and a contact angle of 132°. Due to its low surface energy, it exhibits good water barrier properties (water vapor permeability is 20 g m³ / s). -2 day -1 The material has a fracture strength of 80.32 MPa and a Young's modulus of 3.16 GPa, and its transmittance for ultraviolet light and oxygen is 2% and 15.58 cc m, respectively. -2 day -1 bar -1 It can be completely degraded in natural soil within 85 days.

[0084] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0085] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. A method for preparing a seaweed-based biodegradable packaging material with adjustable hydrophilicity and hydrophobicity, characterized in that, include: A first mixture containing seaweed polysaccharide, water, and glycerol is provided, and the mixture is heated and stirred to produce a seaweed polysaccharide solution; Solid filler is added to a seaweed polysaccharide solution to uniformly disperse the solid filler into two-dimensional nanosheets with a diameter of 1-10 μm and a thickness of 5-30 nm, forming a second mixed system. The second mixed system is then processed and shaped to obtain a seaweed-based biodegradable packaging material. The solid filler is edible phlogopite powder. A hydrophobic modifier is applied to the surface of the seaweed-based biodegradable packaging material and dried at room temperature to change the surface of the material from hydrophilic to hydrophobic, thereby obtaining a seaweed-based biodegradable packaging material with adjustable hydrophilicity and hydrophobicity. The hydrophobic modifier is composed of an acidic solution in a volume ratio of (1~3):(3~6):(6~10), a low surface energy modifier, and ethanol. The mass percentage of seaweed polysaccharide in the first mixed system is 1%~10%, the mass percentage of glycerol is 0.5%~2.5%, and the mass percentage of solid filler in the second mixed system is 0.1%~5%. The processing and molding process includes uniformly spreading the second mixed system on a plastic petri dish using a solution casting method or a scraping method, and placing it at 35~60℃ and 40~70RH% for 24~120h.

2. The method for preparing the hydrophilic-hydrophobic tunable seaweed-based biodegradable packaging material according to claim 1, characterized in that: The heating temperature of the first mixing system is 45~70℃, the heating time is 30~240min, and the stirring speed is 550~1000rpm.

3. The method for preparing the hydrophilic-hydrophobic tunable seaweed-based biodegradable packaging material according to claim 1, characterized in that: The solid filler is uniformly dispersed in the seaweed polysaccharide solution for 2-5 hours.

4. The method for preparing the hydrophilic-hydrophobic tunable seaweed-based biodegradable packaging material according to claim 1, characterized in that: The seaweed polysaccharide includes at least one of seaweed cellulose, sodium alginate, and agar.

5. The method for preparing the hydrophilic-hydrophobic tunable seaweed-based biodegradable packaging material according to claim 1, characterized in that: The acidic solution includes any one of hydrochloric acid, sulfuric acid, nitric acid, and acetic acid solutions; the low surface energy modifier includes any one or a combination of two or more of the following: triethoxysilane, tetraethoxysilane, n-octyltrimethoxysilane, dodecylmethyldimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, n-octadecyltriethoxysilane, perfluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, and perfluorooctyltriethoxysilane.

6. The method for preparing the hydrophilic-hydrophobic tunable seaweed-based biodegradable packaging material according to claim 5, characterized in that: The concentration of the acidic solution is 0.005~0.02 mol / L, and the concentration of the low surface energy modifier is 10~20 mmol / L.

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