Preparation method and application of high-barrier antibacterial mildew-proof antioxidant environment-friendly functional material

Abstract

The invention discloses a preparation method and application of a high-barrier antibacterial mildew-proof antioxidant environment-friendly functional material.The preparation method comprises the following steps that firstly, graphene microcapsules are prepared, secondly, the high-barrier antibacterial mildew-proof antioxidant environment-friendly functional material is prepared, the graphene microcapsules and a high-barrier environment-friendly high polymer material serve as raw materials, and the high-barrier antibacterial mildew-proof antioxidant environment-friendly functional material is prepared. And carrying out extrusion molding or calendaring molding to obtain the high-barrier antibacterial mildew-proof antioxidant environment-friendly functional material. According to the microcapsule, graphene is isolated through a shell material, so that the problem of unstable quality of a high-barrier environment-friendly high-molecular material caused by agglomeration and non-uniform dispersion when the graphene material is introduced into the environment-friendly high-molecular material is avoided; the mixing difficulty of the graphene microcapsule and an environment-friendly high polymer material is reduced, and the high-barrier, antibacterial, mildew-proof and antioxidant environment-friendly functional material is provided and has high barrier property, antibacterial property, mildew-proof property and antioxidant property.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a high-barrier antibacterial, anti-mildew, anti-oxidation and environmentally friendly functional material. Background Art

[0002] With the advancement of modern science and technology and the enhancement of environmental awareness, the field of materials science is undergoing unprecedented changes. Although traditional polymer materials, such as polyethylene and polypropylene, have excellent physical and chemical properties, they are obviously insufficient in terms of barrier properties, antibacterial properties, mildew resistance, antioxidant properties, and environmentally friendly degradability. Especially in the fields of food packaging, medical supplies, and electronic product packaging, higher requirements are placed on the high barrier properties, antibacterial and mildew resistance, and antioxidant properties of materials. At the same time, with the global emphasis on sustainable development, the research and development of environmentally friendly degradable materials has become a top priority.

[0003] At present, high barrier materials are mainly realized through multi-layer co-extrusion, surface coating, nanocomposite and other technologies. For example, polymer materials such as ethylene-vinyl alcohol copolymer (EVOH) and polyvinylidene chloride (PVDC) are widely used in food packaging due to their excellent barrier properties. However, these materials are mediocre in antibacterial, anti-mildew and anti-oxidation, and most of them are non-degradable, which imposes a long-term burden on the environment. Antibacterial and anti-mildew materials are mainly realized by adding inorganic antibacterial agents (such as silver ions, zinc oxide, etc.) or organic antibacterial agents (such as quaternary ammonium salts, phenolic compounds, etc.). These materials are effective in inhibiting the growth of bacteria and molds, but often have problems such as antibacterial agent migration, affecting the mechanical properties of materials, and non-degradability. Antioxidant materials mainly improve the antioxidant properties of materials by adding antioxidants (such as vitamin E, tea polyphenols, ascorbic acid, etc.). However, these antioxidants may gradually fail during long-term use, and some antioxidants have safety hazards. Environmentally friendly degradable materials mainly include starch-based, polylactic acid (PLA), polyhydroxyalkanoates (PHA), etc. These materials can degrade quickly in the natural environment, reducing environmental pollution. However, they often have difficulty meeting high requirements in terms of barrier properties, antibacterial and anti-oxidation properties.

[0004] In summary, most of the materials currently on the market can only meet a single or a few performance requirements, and it is difficult to achieve high barrier, antibacterial and mildew resistance, antioxidant and environmentally friendly biodegradability at the same time. In addition, the preparation process of some materials is complicated and costly, which limits their wide application.

[0005] As a new material with strong performance, graphene has excellent performance in many aspects, especially in terms of high barrier properties. It has high application value and a wide range of uses. Its barrier mechanism originates from the maze effect of graphene. The two-dimensional sheet structure of graphene can form a "maze-like" structure with layers stacked and staggered. This structure can form a dense barrier layer in the coating, effectively preventing corrosive media, gas molecules (such as oxygen, toluene vapor) and water, chloride ions, etc. from penetrating into the substrate, thereby protecting the substrate from corrosion or pollution. At the same time, graphene has good hydrophobic properties, which can further block the penetration of moisture in the environment, which is particularly important in improving the barrier properties of packaging materials.

[0006] Graphene is a carbon atom in the form of sp 2 Two-dimensional carbon nanomaterials composed of hexagonal honeycomb lattices composed of hybrid orbitals, graphene and its derivatives, such as graphene, graphene oxide and reduced graphene oxide, all have effective antibacterial, mildew-proof and antioxidant effects. At the same time, graphene has unique mechanical properties and easy modification characteristics, which gives it a unique position in the field of materials science. However, the antibacterial, mildew-proof and antioxidant capabilities of pure graphene materials are limited, and it is difficult to meet the modern requirements for an antibacterial and antiviral rate of nearly 100%. Therefore, it is urgent to provide a graphene composite material that is antibacterial, mildew-proof and antioxidant and has excellent high barrier properties. Summary of the invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a preparation method and application of a high-barrier, antibacterial, anti-mildew, and anti-oxidation environmentally friendly functional material.

[0008] In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

[0009] A method for preparing a high-barrier, antibacterial, anti-mildew, anti-oxidation and environmentally friendly functional material comprises the following steps:

[0010] 1. Preparation of graphene microcapsules, wherein the graphene microcapsules use sodium dehydroacetate, graphene oxide and kapok flavonoids as core materials, and use one of chitosan, lignin, modified starch and modified carboxymethyl cellulose as shell materials;

[0011] Core material preparation:

[0012] Extraction of kapok flavonoids: Put the crushed kapok flowers in a flask, add ethanol solution into it, treat with 15-45kHz ultrasonic wave at 40-70℃ for 2-4h, let stand, separate, filter, take out the filtrate and distill under reduced pressure, dissolve the product in water, and obtain kapok flavonoids;

[0013] Preparation of core material solution: adding graphene oxide to deionized water, using ultrasound or mechanical stirring to evenly disperse it, and obtaining a uniform graphene dispersion solution after centrifugation or standing; then adding sodium dehydroacetate, kapok flavonoids and surfactant thereto, maintaining the concentration of sodium dehydroacetate at 0.5-2.0 mmol / L, the concentration of graphene oxide solution at 0.15-0.45 mg / mL, the amount of kapok flavonoids added at 0.1-1 mL, and the concentration of surfactant at 0.2-2.3 mM, to obtain a core material solution;

[0014] Treatment of shell material solution: treating the shell material into a shell material solution;

[0015] Emulsification and cross-linking: Add the core material solution to the shell material solution and stir to obtain a graphene mixture. Stir at a stirring rate of 300 to 3000 rpm for 5 to 30 minutes to disperse evenly and prepare a stable suspension. Then add a cross-linking agent, drop acetic acid, adjust the pH to 5.5, keep warm at 70°C, continue the reaction for 5 hours, filter the product, wash the product with ethanol, remove unreacted shell material and impurities, and vacuum dry at 60°C for 24 hours to obtain graphene microcapsules;

[0016] 2. Preparation of high barrier, antibacterial, antifungal, antioxidant and environmentally friendly functional materials

[0017] With graphene microcapsules and high-barrier environmentally friendly polymer materials as raw materials, high-barrier antibacterial, anti-mildew and antioxidant environmentally friendly functional materials are obtained after extrusion molding or calendering molding.

[0018] Preferably, the method for preparing the shell material solution is: when the shell material is chitosan, dissolve the chitosan in an acidic solution, the content of chitosan with a weight average molecular weight of 2000 to 150000 in the system is 30wt% to 90wt%, adjust the pH value to 4 to 6 until the chitosan can be completely dissolved, keep the temperature at 25 to 50°C, react for 6 to 24 hours, and form the shell material solution.

[0019] Preferably, the preparation method of the shell material solution is as follows: when the shell material is lignin, deionized water is added to the lignin, and the content of lignin with a weight average molecular weight of 2000 to 150000 in the system is 30wt% to 90wt%, forming a lignin suspension. Sodium hydroxide, hydrogen peroxide solution and cuprous sulfate are added to obtain a mixed solution; the mixed solution is reacted at 80 to 120°C for 1 to 3 hours to modify the lignin. Sodium hydroxide solution is added to adjust the pH of the mixed solution to 9 to 12; the temperature is lowered to 20 to 25°C, an amine substance is added, the reaction is carried out for 0.1 to 2 hours, a formaldehyde solution is added, the temperature is raised to 80 to 100°C, and the reaction is continued for 2 to 5 hours to generate a lignin emulsifier, i.e., the shell material solution.

[0020] Preferably, the shell material solution is prepared as follows: when the shell material is modified starch, deionized water is added to the esterified starch, heated to 70-90° C. and stirred until the esterified starch is completely dissolved, and the content of the esterified starch with a weight average molecular weight of 2000-150000 in the system is 30wt%-90wt%, thereby forming the shell material solution.

[0021] Preferably, the shell material solution is prepared as follows: when the shell material is modified carboxymethyl cellulose, isopropanol is added to the modified carboxymethyl cellulose, heated to 35° C. and stirred until the modified carboxymethyl cellulose is completely dissolved, and the content of the modified carboxymethyl cellulose with a weight average molecular weight of 2000 to 150000 in the system is 30wt% to 90wt%, thereby forming the shell material solution.

[0022] Preferably, the cross-linking agent is one of genipin, carbodiimide, and glycerol glycidyl ether.

[0023] Preferably, the high barrier environmentally friendly polymer material is one of polyvinyl alcohol (PVA), polylactic acid-co-dimethyl sulfide, polyhydroxyalkanoate (PHA), polymethyl ethylene carbonate (PPC), polybutylene adipate / terephthalate (PBAT), and EVOH / PLA composite materials.

[0024] Preferably, the surfactant is sodium dodecyl sulfate.

[0025] A high-barrier, antibacterial, mildew-proof, and antioxidant environmentally friendly functional material is prepared by the above-mentioned method for preparing a high-barrier, antibacterial, mildew-proof, and antioxidant environmentally friendly functional material.

[0026] The above-mentioned high-barrier, antibacterial, anti-mildew, antioxidant and environmentally friendly functional material is used in packaging bags and boxes for food, medicine, medical equipment, cosmetics and electronic products.

[0027] The beneficial effects of the present invention are:

[0028] The first purpose of the present invention is to provide a graphene microcapsule, which isolates graphene through a shell material, thereby avoiding the problem of graphene material being introduced into environmentally friendly polymer materials and agglomerating and unevenly dispersing, resulting in unstable quality of high-barrier environmentally friendly polymer materials. In addition, the microcapsule can be formed with high-barrier environmentally friendly polymer materials through extrusion or calendering to achieve a solvent-free green process, thereby avoiding the impact of organic solvents on the environment and improving the safety of the material.

[0029] The second object of the present invention is to provide a method for preparing the above-mentioned graphene microcapsules, which uses emulsion polymerization to wrap the graphene material in a polymer shell material, thereby reducing the difficulty of mixing the graphene microcapsules with the environmentally friendly polymer material.

[0030] The third purpose of the present invention is to provide a high-barrier, antibacterial, mildew-proof and antioxidant environmentally friendly functional material, which combines the multiple advantages of graphene, sodium dehydroacetate, kapok flavonoids, degradable polymer materials, etc., and has high barrier, antibacterial, mildew-proof and antioxidant properties.

[0031] The fourth purpose of the present invention is to provide a method for preparing the above-mentioned high-barrier, antibacterial, anti-mildew, and antioxidant environmentally friendly functional materials. The preparation method adopts extrusion or calendering molding technology and does not require pre-dissolution treatment of the environmentally friendly polymer materials. Therefore, the process flow is simple, the production efficiency is high, and the product quality is stable. DETAILED DESCRIPTION

[0032] References to embodiments of the present invention will now be provided in detail, one or more examples of which are described below. Each example is provided as an explanation rather than a limitation of the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present invention without departing from the scope or spirit of the present invention. For example, a feature illustrated or described as part of one embodiment may be used in another embodiment to produce a further embodiment.

[0033] Therefore, it is intended that the present invention covers such modifications and variations that fall within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present invention are disclosed in or are obvious from the following detailed description. Those of ordinary skill in the art will appreciate that this discussion is only a description of exemplary embodiments and is not intended to limit the broader aspects of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0035] Except as shown in the operating examples or otherwise indicated, all numbers used in the specification and claims to indicate the amount of ingredients, physicochemical properties, etc. are understood to be adjusted by the term "about" in all cases. For example, therefore, unless otherwise indicated, the numerical parameters listed in the above specification and the attached claims are approximate values, and those skilled in the art can use the teachings disclosed herein to seek to obtain the desired properties and appropriately change these approximate values. The use of numerical ranges expressed as endpoints includes all numbers within the range and any range within the range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4 and 5, etc.

[0036] Example 1

[0037] Preparation of graphene functional microcapsules: the core material is graphene (the concentration of graphene oxide solution is 0.15 mg / mL), sodium dehydroacetate, kapok flavonoids, and the shell material is chitosan.

[0038] Step 1: Core material preparation

[0039] Kapok flavonoids extraction:

[0040] The crushed kapok flowers were placed in a flask, and ethanol solution was added thereto. The mixture was treated with 30kHz ultrasonic wave at 50°C for 3 hours, allowed to stand, separated, filtered, and the filtrate was taken out and distilled under reduced pressure. The product was dissolved in water to obtain kapok flavonoid compounds.

[0041] Preparation of core material solution: add graphene oxide to deionized water, use ultrasound or mechanical stirring to evenly disperse it, and obtain a uniform graphene dispersion solution after centrifugation or standing; then add sodium dehydroacetate, kapok flavonoids and sodium dodecyl sulfate thereto, maintain the concentration of sodium dehydroacetate at 1 mmol / L, the concentration of graphene oxide solution at 0.15 mg / mL, the amount of kapok flavonoids added is 0.5 mL, and the concentration of sodium dodecyl sulfate is 1.5 mM, to obtain a stable core material solution.

[0042] Step 2: Shell material preparation

[0043] Chitosan dissolution: Chitosan is dissolved in an acidic solution (such as acetic acid solution), the content of chitosan in this system is 50 wt%, and the pH value is adjusted to a state where chitosan can be completely dissolved to form a chitosan solution.

[0044] Step 3: Microcapsule preparation

[0045] Emulsification and cross-linking: Add the core material solution to the chitosan solution in the second step, continue stirring for 15 minutes, and obtain a graphene / chitosan mixture; stir at a stirring rate of 800r / min for 15 minutes to disperse evenly and prepare a stable suspension. Then add the cross-linking agent genipin, further add acetic acid, adjust the pH to 5.5, keep warm at 70°C, continue to react for 5 hours, filter the product, wash the product with ethanol, remove unreacted chitosan and other impurities, and vacuum dry at 60°C for 24 hours to obtain the graphene microcapsules of the present invention.

[0046] Step 4: Performance testing and optimization

[0047] Performance testing: The average particle size of graphene functional microcapsules is 3.05μm.

[0048] Example 2

[0049] Preparation of graphene functional microcapsules: the core material is graphene (the concentration of graphene oxide solution is 0.25 mg / mL), sodium dehydroacetate, kapok flavonoids, and the shell material is chitosan.

[0050] Step 1: Core material preparation

[0051] Kapok flavonoids extraction:

[0052] The crushed kapok flowers were placed in a flask, and ethanol solution was added thereto. The mixture was treated with 30kHz ultrasonic wave at 50°C for 3 hours, allowed to stand, separated, filtered, and the filtrate was taken out and distilled under reduced pressure. The product was dissolved in water to obtain kapok flavonoid compounds.

[0053] Preparation of core material solution: Add a certain amount of graphene oxide to deionized water, use ultrasonic or mechanical stirring to evenly disperse it, and obtain a uniform graphene dispersion solution after centrifugation or standing; then add sodium dehydroacetate, kapok flavonoids and sodium dodecyl sulfate, maintain the concentration of sodium dehydroacetate at 1mmol / L, the concentration of graphene oxide solution at 0.25mg / mL, the amount of kapok flavonoids added is 0.5mL, and the concentration of sodium dodecyl sulfate is 1.5mM to obtain a stable core material solution.

[0054] Step 2: Shell material preparation

[0055] Chitosan dissolution: Chitosan is dissolved in an acidic solution (such as acetic acid solution), the content of chitosan in this system is 50 wt%, and the pH value is adjusted to a state where chitosan can be completely dissolved to form a chitosan solution.

[0056] Step 3: Microcapsule preparation

[0057] Emulsification and cross-linking: Add the core material solution to the chitosan solution in the second step, continue stirring for 15 minutes, and obtain a graphene / chitosan mixture; stir at a stirring rate of 800r / min for 15 minutes to disperse evenly and prepare a stable suspension. Then add the cross-linking agent genipin, further add acetic acid, adjust the pH to 5.5, keep warm at 70°C, continue to react for 5 hours, filter the product, wash the product with ethanol, remove unreacted chitosan and other impurities, and vacuum dry at 60°C for 24 hours to obtain the graphene functional microcapsules of the present invention.

[0058] Step 4: Performance testing and optimization

[0059] Performance testing: The average particle size of graphene functional microcapsules is 3.55μm.

[0060] Example 3

[0061] Preparation of graphene functional microcapsules: the core material is graphene (the concentration of graphene oxide solution is 0.35 mg / mL), sodium dehydroacetate, kapok flavonoids, and the shell material is chitosan.

[0062] Step 1: Core material preparation

[0063] Kapok flavonoids extraction:

[0064] The crushed kapok flowers were placed in a flask, and ethanol solution was added thereto. The mixture was treated with 30kHz ultrasonic wave at 50°C for 3 hours, allowed to stand, separated, filtered, and the filtrate was taken out and distilled under reduced pressure. The product was dissolved in water to obtain kapok flavonoid compounds.

[0065] Preparation of core material solution: Add a certain amount of graphene oxide to deionized water, use ultrasound or mechanical stirring to evenly disperse it, and obtain a uniform graphene dispersion solution after centrifugation or standing; then add sodium dehydroacetate, kapok flavonoids and sodium dodecyl sulfate, maintain the concentration of sodium dehydroacetate at 1mmol / L, the concentration of graphene oxide solution at 0.35mg / mL, the amount of kapok flavonoids added is 0.5mL, and the concentration of sodium dodecyl sulfate is 1.5mM, to obtain a stable core material solution.

[0066] Step 2: Shell material preparation

[0067] Chitosan dissolution: Chitosan is dissolved in an acidic solution (such as acetic acid solution), the content of chitosan in this system is 50 wt%, and the pH value is adjusted to a state where chitosan can be completely dissolved to form a chitosan solution.

[0068] Step 3: Microcapsule preparation

[0069] Emulsification and cross-linking: Add the core material solution of the first step to the chitosan solution of the second step, continue stirring for 15 minutes, and obtain a graphene / chitosan mixture; stir at a stirring rate of 800r / min for 15 minutes to disperse evenly and prepare a stable suspension. Then add the cross-linking agent genipin, further add acetic acid, adjust the pH to 5.5, keep warm at 70°C, continue to react for 5 hours, filter the product, wash the product with ethanol, remove unreacted chitosan and other impurities, and vacuum dry at 60°C for 24 hours to obtain the graphene functional microcapsules of the present invention.

[0070] Step 4: Performance testing and optimization

[0071] Performance testing: The average particle size of graphene functional microcapsules is 4.67μm.

[0072] Example 4

[0073] Preparation of graphene functional microcapsules: the core material is graphene (the concentration of graphene oxide solution is 0.25 mg / mL), sodium dehydroacetate, kapok flavonoids, and the shell material is lignin.

[0074] Step 1: Core material preparation

[0075] Kapok flavonoids extraction:

[0076] The crushed kapok flowers were placed in a flask, and ethanol solution was added thereto. The mixture was treated with 30kHz ultrasonic wave at 50°C for 3 hours, allowed to stand, separated, filtered, and the filtrate was taken out and distilled under reduced pressure. The product was dissolved in water to obtain kapok flavonoid compounds.

[0077] Preparation of core material solution: Add a certain amount of graphene oxide to deionized water, use ultrasonic or mechanical stirring to evenly disperse it, and obtain a uniform graphene dispersion solution after centrifugation or standing; then add sodium dehydroacetate, kapok flavonoids and sodium dodecyl sulfate, maintain the concentration of sodium dehydroacetate at 1mmol / L, the concentration of graphene oxide solution at 0.25mg / mL, the amount of kapok flavonoids added is 0.5mL, and the concentration of sodium dodecyl sulfate is 1.5mM to obtain a stable core material solution.

[0078] Step 2: Shell material preparation

[0079] Lignin dissolution: Add deionized water to lignin, the content of lignin in this system is 50wt%, to form a lignin suspension. Add sodium hydroxide, hydrogen peroxide solution and cuprous sulfate to obtain a mixed solution. React the mixed solution at 80-120°C for 1-3h to modify the lignin. Add sodium hydroxide solution and adjust the pH of the mixed solution to 9-12. Cool down to 20-25°C, add amine substances, and react for 0.1-2h. Add formaldehyde solution, heat to 80-100°C, and continue to react for 2-5h to generate a lignin emulsifier, i.e., a lignin solution.

[0080] Step 3: Microcapsule preparation

[0081] Emulsification and cross-linking: Add the core material solution of the first step to the lignin solution of the second step, continue stirring for 15 minutes, and obtain a graphene / lignin mixture; stir at a stirring rate of 800r / min for 15 minutes to disperse evenly and prepare a stable suspension. Then add the cross-linking agent genipin, further add acetic acid, adjust the pH to 5.5, keep warm at 70°C, continue to react for 5 hours, filter the product, wash the product with ethanol, remove unreacted lignin and other impurities, and vacuum dry at 60°C for 24 hours to obtain the graphene functional microcapsules of the present invention.

[0082] Step 4: Performance testing and optimization

[0083] Performance testing: The average particle size of graphene functional microcapsules is 3.52μm.

[0084] Example 5

[0085] Preparation of graphene functional microcapsules: the core material is graphene (the concentration of graphene oxide solution is 0.25 mg / mL), sodium dehydroacetate, kapok flavonoids, and the shell material is modified starch (provided by Hebei Pengyu Biotechnology Co., Ltd., the CAS number of modified starch is 74-79-3)

[0086] Step 1: Core material preparation

[0087] Kapok flavonoids extraction:

[0088] The crushed kapok flowers were placed in a flask, and ethanol solution was added thereto. The mixture was treated with 30kHz ultrasonic wave at 50°C for 3 hours, allowed to stand, separated, filtered, and the filtrate was taken out and distilled under reduced pressure. The product was dissolved in water to obtain kapok flavonoid compounds.

[0089] Preparation of core material solution: Add a certain amount of graphene oxide to deionized water, use ultrasonic or mechanical stirring to evenly disperse it, and obtain a uniform graphene dispersion solution after centrifugation or standing; then add sodium dehydroacetate, kapok flavonoids and sodium dodecyl sulfate, maintain the concentration of sodium dehydroacetate at 1mmol / L, the concentration of graphene oxide solution at 0.25mg / mL, the amount of kapok flavonoids added is 0.5mL, and the concentration of sodium dodecyl sulfate is 1.5mM to obtain a stable core material solution.

[0090] Step 2: Shell material preparation

[0091] Dissolving modified starch: Add deionized water to the esterified starch, heat to 70-90°C and stir until the esterified starch is completely dissolved. The content of modified starch in this system is 50wt%, forming a modified starch solution.

[0092] Step 3: Microcapsule preparation

[0093] Emulsification and cross-linking: Add the core material solution of the first step to the modified starch solution of the second step, continue stirring for 15 minutes, and obtain a graphene / modified starch mixture; stir at a stirring rate of 800r / min for 15 minutes to disperse evenly and prepare a stable suspension. Then add the cross-linking agent genipin, further add acetic acid, adjust the pH to 5.5, keep warm at 70°C, continue to react for 5 hours, filter the product, wash the product with ethanol, remove unreacted modified starch and other impurities, and vacuum dry at 60°C for 24 hours to obtain the graphene functional microcapsules of the present invention.

[0094] Step 4: Performance testing and optimization

[0095] Performance testing: The average particle size of graphene functional microcapsules is 3.87μm.

[0096] Example 6

[0097] Preparation of graphene functional microcapsules: the core material is graphene (the concentration of graphene oxide solution is 0.25 mg / mL), sodium dehydroacetate, kapok flavonoids, and the shell material is modified carboxymethyl cellulose (modified carboxymethyl cellulose, provided by Dacheng Yibo Chemical Co., Ltd., the link of the raw material is https: / / www.zhaosw.com / product / detail / 204952293)

[0098] Step 1: Core material preparation

[0099] Kapok flavonoids extraction:

[0100] The crushed kapok flowers were placed in a flask, and ethanol solution was added thereto. The mixture was treated with 30kHz ultrasonic wave at 50°C for 3 hours, allowed to stand, separated, filtered, and the filtrate was taken out and distilled under reduced pressure. The product was dissolved in water to obtain kapok flavonoid compounds.

[0101] Preparation of core material solution: Add a certain amount of graphene oxide to deionized water, use ultrasonic or mechanical stirring to evenly disperse it, and obtain a uniform graphene dispersion solution after centrifugation or standing; then add sodium dehydroacetate, kapok flavonoids and sodium dodecyl sulfate, maintain the concentration of sodium dehydroacetate at 1mmol / L, the concentration of graphene oxide solution at 0.25mg / mL, the amount of kapok flavonoids added is 0.5mL, and the concentration of sodium dodecyl sulfate is 1.5mM to obtain a stable core material solution.

[0102] Step 2: Shell material preparation

[0103] Dissolving modified carboxymethyl cellulose: Add an appropriate amount of isopropanol to the modified carboxymethyl cellulose, heat to 35°C and stir until the modified carboxymethyl cellulose is completely dissolved. The content of the modified carboxymethyl cellulose in this system is 50wt%, forming a modified carboxymethyl cellulose suspension, i.e., a shell material solution.

[0104] Step 3: Microcapsule preparation

[0105] Emulsification and cross-linking: Add the core material solution of the first step to the modified carboxymethyl cellulose suspension of the second step, continue stirring for 15 minutes, and obtain a graphene / modified carboxymethyl cellulose mixture; stir at a stirring rate of 800r / min for 15 minutes to disperse evenly and prepare a stable suspension. Then add the cross-linking agent genipin, further add acetic acid, adjust the pH to 5.5, keep warm at 70°C, continue to react for 5 hours, filter the product, wash the product with ethanol, remove the unreacted modified carboxymethyl cellulose and other impurities, and vacuum dry at 60°C for 24 hours to obtain the graphene functional microcapsules of the present invention.

[0106] Step 4: Performance testing and optimization

[0107] Performance testing: The average particle size of graphene functional microcapsules is 3.58μm.

[0108] Embodiments 7 to 12

[0109] The graphene functional microcapsules of Examples 1 to 6 above were used to prepare high barrier, antibacterial, mildew-proof, and antioxidant environmentally friendly polymer materials, and the preparation processes were as follows:

[0110] 1. In a mixer, polyvinyl alcohol (PVA) and graphene functional microcapsules were mixed in a ratio of 95:5;

[0111] 2. Add the mixed materials into the twin-screw extruder for melt mixing, set the temperature to 210-240°C, and set the feed rate and screw speed to 20rpm and 100rpm respectively;

[0112] 3. After extrusion, the mixed material is cooled by air cooling equipment and cut into pellets by a pelletizer;

[0113] 4. Add the pellets to the feed port of the film blowing machine, set the film blowing temperature to 205-220°C, the blowing ratio to 2.5:1, and blow out a PVA film with a thickness of 35μm±5μm.

[0114] Examples 13 to 18

[0115] 1. In a mixer, polyhydroxyalkanoate (PHA) and graphene functional microcapsules were mixed in a ratio of 95:5;

[0116] 2. Add the mixed materials into the twin-screw extruder for melt mixing, set the temperature to 180-190°C, and set the feed rate and screw speed to 20rpm and 100rpm respectively;

[0117] 3. After extrusion, the mixed material is cooled by air cooling equipment and cut into pellets by a pelletizer;

[0118] 4. Add the pellets into the feed port of the film blowing machine, set the film blowing temperature to 140-180°C, the blowing ratio to 2.5:1, and blow out a PHA film with a thickness of 35μm±5μm.

[0119] The PHA film and PVA film prepared as above can be applied in many fields, such as packaging bags, packaging films and packaging boxes for food, medicine, medical equipment, cosmetics and electronic products.

[0120] Comparative Example 1

[0121] The difference from Example 8 is that no graphene functional microcapsules are added, and the addition amounts of other raw materials and the preparation process are the same.

[0122] Comparative Example 2

[0123] The difference from Example 8 is that graphene oxide, sodium dehydroacetate and kapok flavonoids are directly added to polyvinyl alcohol in an amount that is the same as the actual content in Example 7, and the mixture is granulated and film-drawn.

[0124] Performance evaluation methods and implementation standards of materials of Examples 7 to 18 and Comparative Examples 1 and 2:

[0125] 1. Comprehensive mechanical properties are evaluated by testing tensile strength. The tensile strength test refers to the film tensile performance test method of GB 13022-1991. Among them, MD ~ longitudinal direction, TD ~ transverse direction; MD: Machine Direction, which means longitudinal direction. TD: Transverse Direction, which is perpendicular to the machine direction, which means transverse direction.

[0126] 2. Gas barrier test: refer to GB / T19789-2021 Packaging material plastic film and sheet oxygen permeability test coulometer detection method test.

[0127] 3. Antibacterial performance test: refer to GB / T 31402-2015 Plastic Surface Antibacterial Performance Test Method Test, test bacteria: Staphylococcus aureus.

[0128] 4. Anti-fungal test: Refer to ASTM G21~15 (2021) Determination of antifungal properties of synthetic polymer materials.

[0129] 5. Antioxidant performance test: The products of Examples 7 to 18 and Comparative Examples 1 to 2 were placed in 200 mL of a 50 μg / mL DPPH solution for 6 h, and the scavenging effect of the samples on DPPH free radicals was evaluated by measuring the change in absorbance value.

[0130] Table 1 Formulations of Examples 1 to 18

[0131]

[0132]

[0133] Table 2 Formula of Comparative Examples 1 to 2

[0134]

[0135] Table 3 Performance test results of embodiments and comparative examples

[0136] The barrier, antibacterial, mildew-proof, antioxidant properties, mechanical strength, etc. of the environmentally friendly polymer materials of Examples 7 to 18 were tested and compared with Comparative Examples 1 and 2. The results are shown in Table 3.

[0137]

[0138]

[0139] It can be seen from the data in Table 3 that the environmentally friendly polymer material obtained by the present invention according to the above specific implementation has excellent barrier, antibacterial, mildew-proof and antioxidant properties.

[0140] Although the present invention is described in detail with reference to the above embodiments, it is obvious to those skilled in the art through this disclosure that various changes or modifications may be made to the present invention without departing from the principle and spirit of the present invention defined by the claims. Therefore, the detailed description of the embodiments of the present disclosure is only used to explain, not to limit the present invention, but the scope of protection is limited by the content of the claims.

Claims

1. A method for preparing a high barrier, antibacterial, mildew proof, antioxidant and environmentally friendly functional material, characterized in that: The following steps are included:

1. Preparation of graphene microcapsules, wherein the graphene microcapsules use sodium dehydroacetate, graphene oxide and kapok flavonoids as core materials, and use one of chitosan, lignin, modified starch and modified carboxymethyl cellulose as shell materials; Core material preparation: Extraction of kapok flavonoids: Put the crushed kapok flowers in a flask, add ethanol solution into it, treat with 15-45kHz ultrasonic wave at 40-70℃ for 2-4h, let stand, separate, filter, take out the filtrate and distill under reduced pressure, dissolve the product in water, and obtain kapok flavonoids; Preparation of core material solution: adding graphene oxide to deionized water, using ultrasound or mechanical stirring to evenly disperse it, and obtaining a uniform graphene dispersion solution after centrifugation or standing; then adding sodium dehydroacetate, kapok flavonoids and surfactant thereto, maintaining the concentration of sodium dehydroacetate at 0.5-2.0 mmol / L, the concentration of graphene oxide solution at 0.15-0.45 mg / mL, the amount of kapok flavonoids added at 0.1-1 mL, and the concentration of surfactant at 0.2-2.3 mM, to obtain a core material solution; Preparation of shell material solution: treating the shell material into a shell material solution; Emulsification and cross-linking: adding the core material solution to the shell material solution and stirring to obtain a graphene mixture, stirring at a stirring rate of 300 to 3000 rpm for 5 to 30 minutes to disperse evenly and prepare a stable suspension; then adding a cross-linking agent, dropping acetic acid, adjusting the pH to 5.5, keeping the temperature at 70°C, continuing the reaction for 5 hours, filtering the product, washing the product with ethanol, removing unreacted shell material and impurities, and vacuum drying at 60°C for 24 hours to obtain graphene microcapsules; 2. Preparation of high barrier, antibacterial, antifungal, antioxidant and environmentally friendly functional materials With graphene microcapsules and high-barrier environmentally friendly polymer materials as raw materials, high-barrier antibacterial, anti-mildew and antioxidant environmentally friendly functional materials are obtained after extrusion molding or calendering molding.

2. The method for preparing a high barrier, antibacterial, antifungal, and antioxidant environmentally friendly functional material according to claim 1, characterized in that: The preparation method of the shell material solution is as follows: when the shell material is chitosan, the chitosan is dissolved in an acidic solution, the content of chitosan with a weight average molecular weight of 2000 to 150000 in the system is 30wt% to 90wt%, the pH value is adjusted to 4 to 6 until the chitosan can be completely dissolved, the temperature is kept at 25 to 50° C., and the reaction is performed for 6 to 24 hours to form the shell material solution.

3. The method for preparing a high barrier, antibacterial, antifungal, and antioxidant environmentally friendly functional material according to claim 1, characterized in that: The preparation method of the shell material solution is as follows: when the shell material is lignin, deionized water is added to the lignin, the content of lignin with a weight average molecular weight of 2000-150000 in the system is 30wt%-90wt%, a lignin suspension is formed, sodium hydroxide, hydrogen peroxide solution and cuprous sulfate are added to obtain a mixed solution; the mixed solution is reacted at 80-120°C for 1-3h, sodium hydroxide solution is added, and the pH of the mixed solution is adjusted to 9-12; the temperature is lowered to 20-25°C, an amine substance is added, the reaction is carried out for 0.1-2h, a formaldehyde solution is added, the temperature is raised to 80-100°C, and the reaction is continued for 2-5h to generate a lignin emulsifier, i.e., the shell material solution.

4. The method for preparing a high barrier, antibacterial, antifungal, and antioxidant environmentally friendly functional material according to claim 1, characterized in that: The preparation method of the shell material solution is as follows: when the shell material is modified starch, deionized water is added to the esterified starch, heated to 70-90° C. and stirred until the esterified starch is completely dissolved, and the content of the esterified starch with a weight average molecular weight of 2000-150000 in the system is 30wt%-90wt%, forming the shell material solution.

5. The method for preparing a high barrier, antibacterial, antifungal, and antioxidant environmentally friendly functional material according to claim 1, characterized in that: The preparation method of the shell material solution is as follows: when the shell material is modified carboxymethyl cellulose, isopropanol is added to the modified carboxymethyl cellulose, heated to 35° C. and stirred until the modified carboxymethyl cellulose is completely dissolved, and the content of the modified carboxymethyl cellulose with a weight average molecular weight of 2000 to 150000 in the system is 30wt% to 90wt%, thereby forming the shell material solution.

6. The method for preparing a high barrier, antibacterial, antifungal, and antioxidant environmentally friendly functional material according to claim 1, characterized in that: The cross-linking agent is one of genipin, carbodiimide, and glycerol glycidyl ether.

7. The method for preparing a high barrier, antibacterial, antifungal, and antioxidant environmentally friendly functional material according to claim 1, characterized in that: The high barrier environmentally friendly polymer material is one of polyvinyl alcohol (PVA), polylactic acid-co-dimethyl sulfide, polyhydroxyalkanoate (PHA), polymethyl ethylene carbonate (PPC), polybutylene adipate / terephthalate (PBAT), and EVOH / PLA composite materials.

8. The method for preparing a high barrier, antibacterial, antifungal, and antioxidant environmentally friendly functional material according to claim 1, characterized in that: The surfactant is sodium lauryl sulfate.

9. A high barrier, antibacterial, mildew proof, antioxidant and environmentally friendly functional material, characterized in that: The high-barrier, antibacterial, mildew-proof, antioxidant and environmentally friendly functional material is made by the preparation method of the high-barrier, antibacterial, mildew-proof, antioxidant and environmentally friendly functional material as described in claim 1.

10. The use of a high barrier, antibacterial, antifungal, and antioxidant environmentally friendly functional material as claimed in claim 9, characterized in that: Used in packaging bags and boxes for food, medicine, medical devices, cosmetics, and electronic products.

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