Preparation method of non-grain biomass full-degradable packaging material

Abstract

The invention relates to the technical field of packaging materials, and particularly discloses a preparation method of a non-grain biomass full-degradable packaging material. The preparation method of the non-grain biomass fully-degradable packaging material comprises the following steps: S1, stirring and mixing polylactic acid, modified biomass fibers, a compatibilizer, an auxiliary agent and water to form a mixture; and S2, putting the mixture into a mold, and carrying out hot press molding to obtain the non-grain biomass full-degradable packaging material, the modified biomass fibers are prepared by modifying biomass fibers prepared by taking corn straws and rice straws as raw materials, and the auxiliaries comprise an antioxidant and a plasticizer. According to the non-grain biomass fully-degradable packaging material and the preparation method thereof, agricultural wastes are taken as raw materials, so that resource utilization of the wastes is realized, environmental pollution is reduced, the prepared non-grain biomass fully-degradable packaging material has waterproofness and mechanical properties, and the application scene of the biomass packaging material can be effectively widened.

Description

Technical Field

[0001] The present application relates to the field of packaging materials, and more specifically, it relates to a preparation method of a non-grain biomass fully degradable packaging material. Background Art

[0002] Packaging materials refer to the materials used for manufacturing packaging containers, packaging decoration, packaging printing, packaging transportation, etc. to meet the requirements of product packaging. Classified by material, they can be divided into paper packaging materials, plastic packaging materials, metal packaging materials, glass packaging materials, wooden packaging materials and composite materials. Among them, plastic packaging plays an important role in the fields of food, beverage, daily necessities, industrial and agricultural production, etc.

[0003] Plastic packaging is widely used due to its good barrier properties, chemical stability and mechanical properties, etc. However, plastic packaging is difficult to degrade in the natural environment. In addition, plastic packaging may also release harmful substances, endangering human health. Biomass packaging materials are a kind of packaging materials made from biomass resources. They have the advantages of being renewable, degradable and environmentally friendly, and gradually become an ideal substitute for traditional packaging materials. However, due to the poor compatibility between polar natural fibers and non-polar polymer matrices in the current biomass packaging materials on the market, the mechanical properties and waterproof properties of the packaging materials are insufficient. With the improvement of people's environmental awareness and the emphasis on sustainable development, the market demand for biomass packaging materials is gradually increasing. Therefore, the present application proposes a preparation method of a non-grain biomass fully degradable packaging material, which can effectively improve the comprehensive performance of biomass packaging materials. Summary of the Invention

[0004] In order to solve the problems of insufficient mechanical properties and waterproof properties of the existing biomass packaging materials, the present application provides a preparation method of a non-grain biomass fully degradable packaging material.

[0005] In a first aspect, the present application provides a preparation method of a non-grain biomass fully degradable packaging material, specifically including the following steps: S1. Stir and mix polylactic acid, modified biomass fiber, compatibilizer, auxiliary agent and water to form a mixture; S2. Put the mixture into a mold and hot press it to obtain a non-grain biomass fully degradable packaging material.

[0006] Preferably, in the step S1, the mass ratio of polylactic acid, modified biomass fiber, compatibilizer, auxiliary agent and water is 100:30 - 50:10 - 12:5:20.

[0007] Preferably, the modified biomass fiber in the step S1 is prepared by the following method: (1) After crushing corn straw and rice straw, stir and mix them evenly, and prepare biomass fibers through steam explosion. The explosion temperature is 280 - 300 °C; (2) Stir and mix the biomass fibers with 1-butyl-3-methylimidazolium chloride, add citric anhydride and triethylamine, raise the temperature, stir and mix, then add pentaerythritol, stir and mix, centrifuge, wash with water and dry to obtain fiber products; (3) Stir and mix the fiber products with gallic acid solution for 1 - 2 h, control the temperature at 50 - 60 °C, wash with water and dry, then add silane coupling agent solution and stir and mix for 1 - 2 h, control the temperature at 60 - 80 °C, centrifuge, wash with water and dry to obtain modified biomass fibers.

[0008] Preferably, in step (1), the mass ratio of corn straw to rice straw is 1 - 2:1.

[0009] Preferably, in step (2), the mass ratio of biomass fibers, 1-butyl-3-methylimidazolium chloride, citric anhydride, triethylamine and pentaerythritol is 10:30 - 50:2 - 4:0.6 - 0.8:1 - 3.

[0010] Preferably, in step (3), the mass ratio of fiber products, gallic acid solution and silane coupling agent solution is 10:3 - 4:1 - 2.

[0011] Preferably, the gallic acid solution is prepared by stirring and mixing gallic acid and water at a mass ratio of 1:100; the silane coupling agent solution is prepared by stirring and mixing γ-aminopropyltriethoxysilane and absolute ethanol at a mass ratio of 1:50.

[0012] Preferably, the compatibilizer is prepared by the following method: 1) Stir and mix the nano calcium carbonate suspension and hyaluronic acid solution, control the temperature, cool and centrifuge, wash with deionized water and dry to obtain modified nano calcium carbonate; 2) Mix the modified nano calcium carbonate with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the modified nano calcium carbonate), ultrasonically disperse to form a modified nano calcium carbonate suspension, add dimethyl itaconate to the modified nano calcium carbonate suspension, stir and mix, then add potassium persulfate, under nitrogen protection, continue to stir and mix, control the temperature, cool and centrifuge, wash with deionized water and dry to obtain a functional substance; 3) Mix the functional substance with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the functional substance), ultrasonically disperse to form a functional substance solution, add sodium alginate solution to the functional substance solution, stir and mix, wash with deionized water and freeze-dry to obtain the compatibilizer.

[0013] Preferably, in step 1), the nano-calcium carbonate suspension is prepared by ultrasonic dispersion of nano-calcium carbonate and absolute ethanol at a mass ratio of 1:20, and the hyaluronic acid solution is prepared by stirring and mixing hyaluronic acid and water at a mass ratio of 1:10.

[0014] Preferably, in step 1), the mass ratio of the nano-calcium carbonate suspension to the hyaluronic acid solution is 5-7:1-3.

[0015] Preferably, in step 2), the mass ratio of the modified nano-calcium carbonate suspension, dimethyl itaconate and potassium persulfate is 8-10:2:0.1.

[0016] Preferably, in step 3), the sodium alginate solution is prepared by stirring and mixing sodium alginate and water at a mass ratio of 1:10.

[0017] Preferably, in step 3), the mass ratio of the functional material solution to the sodium alginate solution is 1-2:1.

[0018] Preferably, in step S1, the auxiliary agent is at least one of an antioxidant, a plasticizer, and a lubricant.

[0019] Preferably, in step S1, the auxiliary agent includes an antioxidant and a plasticizer with a mass ratio of 1:1.

[0020] In a second aspect, the present application provides a non-grain biomass fully degradable packaging material prepared by the above method.

[0021] In summary, the present application has the following beneficial effects: 1. The non-grain biomass fully degradable packaging material prepared in the present application uses corn straw and rice straw as raw materials. These agricultural wastes are widely sourced and low in cost, which not only realizes the resource utilization of waste but also reduces environmental pollution. Through reasonable raw material combination and process innovation, the prepared non-grain biomass fully degradable packaging material has good waterproofness and mechanical properties, which can effectively broaden the application scenarios of biomass packaging materials.

[0022] 2. The modified biomass fiber prepared in this application is obtained by first reacting the biomass fiber prepared from corn straw and rice straw with citric anhydride and pentaerythritol to obtain a fiber product, and then reacting the fiber product with gallic acid solution and silane coupling agent solution. The reaction of the biomass fiber with citric anhydride can reduce the hydrophilicity of the fiber, improve the waterproof property of the packaging material, and at the same time improve the compatibility and bonding force between the fiber and other raw materials, thereby enhancing the mechanical properties of the packaging material. The addition of pentaerythritol can, on the one hand, form a three-dimensional cross-linked structure, improving the stability and mechanical properties of the biomass fiber, and on the other hand, increase the active sites on the fiber surface, promoting the subsequent interaction with the silane coupling agent. Reacting the fiber product with the silane coupling agent solution can not only enhance the interfacial bonding force between the modified biomass fiber and other materials, effectively transfer stress, and improve the mechanical properties of the packaging material, but also improve the water resistance and stability of the modified biomass fiber. Reacting the fiber product with gallic acid solution first can, on the one hand, form active sites on the surface of the fiber product, improving the binding efficiency between the fiber product and the silane coupling agent, and on the other hand, enhance the interfacial bonding strength through intermolecular forces and chemical reactions, thereby further improving the binding force between the modified biomass fiber and other raw materials and improving the mechanical properties of the packaging material.

[0023] 3. The compatibilizer prepared in this application is obtained by grafting dimethyl itaconate onto modified nano calcium carbonate and then compounding it with sodium alginate. Modifying nano calcium carbonate with hyaluronic acid can, on the one hand, form an organic coating layer on the surface of nano calcium carbonate, improving the dispersibility of nano calcium carbonate and promoting the subsequent combination of nano calcium carbonate with sodium alginate, and on the other hand, act as a "bridge" to improve the interfacial compatibility between polylactic acid and the modified biomass fiber, enhancing the interfacial bonding force between them, and further enhancing the mechanical properties of the packaging material. In addition, the modified nano calcium carbonate can also provide more active sites for the subsequent grafting reaction, promoting the grafting efficiency. Grafting dimethyl itaconate onto the modified nano calcium carbonate first can, on the one hand, improve the hydrophobicity and dispersibility of the modified nano calcium carbonate, enhance the interaction with sodium alginate, and form a stable network structure, thereby enhancing the strength and toughness of the packaging material, and on the other hand, form a polymer chain with active groups, forming an interpenetrating network structure with polylactic acid and the modified biomass fiber, significantly improving the mechanical properties and waterproof property of the packaging material. Detailed implementation manners

[0024] The following further elaborates on this application in conjunction with examples.

[0025] In the examples and comparative examples of this application, polylactic acid (CAS: 26100-51-6, purchased from Hubei Baidu Chemical Co., Ltd.), 1-butyl-3-methylimidazolium chloride (product number: 79917-90-1, purchased from Shandong Dyke Biotechnology Co., Ltd.), citric anhydride (CAS: 77-92-9, purchased from Shandong Feier New Materials Co., Ltd.), pentaerythritol (CAS: 115-77-5, purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.), gallic acid (CAS: 149-91-6, purchased from Hubei Xinrunde Chemical Co., Ltd.), γ-aminopropyltriethoxysilane (CAS: 919-30-2, purchased from Hubei Xinkang Pharmaceutical Chemical Co., Ltd.), hyaluronic acid (CAS: 25777-14-4, purchased from Wuhan Haishan Technology Co., Ltd.), nano calcium carbonate (product number: PA92354, purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.), sodium alginate (CAS: 8013-07-8, purchased from Hubei Yongkuo Technology Co., Ltd.), dimethyl itaconate (CAS: 617-52-7, purchased from Hubei Xinmingtai Chemical Co., Ltd.) were used.

[0026] Example 1 A preparation method of a non-grain biomass fully degradable packaging material specifically includes the following steps: S1. According to the mass ratio of polylactic acid, modified biomass fiber, compatibilizer, auxiliary agent and water being 100:30:10:5:20, polylactic acid, modified biomass fiber, starch, auxiliary agent (including antioxidant and plasticizer with a mass ratio of 1:1) and water are stirred and mixed at 400 r / min for 50 min to form a mixture; S2. The mixture is put into a mold and hot-pressed into shape at a temperature of 150 °C and a pressure of 5 MPa for 30 min to obtain the non-grain biomass fully degradable packaging material.

[0027] The modified biomass fiber in step S1 is prepared by the following method: (1) According to the mass ratio of corn straw and rice straw being 1:1, after crushing corn straw and rice straw, they are stirred and mixed at 600 r / min for 30 min, and biomass fiber is prepared by steam explosion, and the explosion temperature is 280 °C; (2) According to the mass ratio of biomass fiber, 1-butyl-3-methylimidazolium chloride, citric anhydride, triethylamine and pentaerythritol being 10:30:2:0.6:1, biomass fiber and 1-butyl-3-methylimidazolium chloride are stirred and mixed at 500 r / min for 30 min, citric anhydride and triethylamine are added, the temperature is raised to 80 °C, stirred and mixed at 400 r / min for 1 h, then pentaerythritol is added, stirred and mixed at 400 r / min for 1 h, centrifuged at 10000 r / min for 10 min, washed with water and dried at 40 °C for 1 h to obtain a fiber product; (3) According to the mass ratio of the fiber product, gallic acid solution and silane coupling agent solution being 10:3:1, mix the fiber product with the gallic acid solution (prepared by stirring and mixing gallic acid and water at a mass ratio of 1:100 at 500 r / min for 30 min) at 400 r / min for 1 h, control the temperature at 50 °C, wash with water, dry at 40 °C for 20 min, then add the silane coupling agent solution (prepared by stirring and mixing γ-aminopropyltriethoxysilane and absolute ethanol at a mass ratio of 1:50 at 500 r / min for 30 min) and mix at 400 r / min for 1 h, control the temperature at 60 °C, centrifuge at 12000 r / min for 30 min, wash with water and then dry at 50 °C for 1 h to obtain the modified biomass fiber.

[0028] The compatibilizer is prepared by the following method: 1) According to the mass ratio of the nano-calcium carbonate suspension and the hyaluronic acid solution being 5:1, mix the nano-calcium carbonate suspension (prepared by dispersing nano-calcium carbonate and absolute ethanol at a mass ratio of 1:20 under ultrasonic power of 300 W, ultrasonic frequency of 20 KHz for 30 min) and the hyaluronic acid solution (prepared by stirring and mixing hyaluronic acid and water at a mass ratio of 1:10 at 500 r / min for 30 min) at 400 r / min for 2 h, control the temperature at 40 °C, cool, centrifuge at 8000 r / min for 20 min, wash with deionized water, and dry at 40 °C for 10 h to obtain the modified nano-calcium carbonate; 2) Mix the modified nano-calcium carbonate with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the modified nano-calcium carbonate), and form a modified nano-calcium carbonate suspension by ultrasonic dispersion at ultrasonic power of 500 W and ultrasonic frequency of 20 KHz for 30 min. According to the mass ratio of the modified nano-calcium carbonate suspension, dimethyl itaconate and potassium persulfate being 8:2:0.1, add dimethyl itaconate to the modified nano-calcium carbonate suspension, mix at 500 r / min for 40 min, then add potassium persulfate, and continue to mix at 300 r / min for 4 h under nitrogen protection, control the temperature at 60 °C, cool, centrifuge at 10000 r / min for 30 min, wash with deionized water, and dry at 45 °C for 2 h to obtain the functional substance; 3) Mix the functional substance with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the functional substance), and form a functional substance solution by ultrasonic dispersion at ultrasonic power of 400 W and ultrasonic frequency of 25 KHz for 30 min. According to the mass ratio of the functional substance solution and the sodium alginate solution being 1:1, add the sodium alginate solution (prepared by stirring and mixing sodium alginate and water at a mass ratio of 1:10 at 500 r / min for 30 min) to the functional substance solution, mix at 400 r / min for 1 h, wash with deionized water, and freeze-dry at -20 °C for 1 h to obtain the compatibilizer.

[0029] Example 2 A preparation method of a non-grain biomass fully degradable packaging material, specifically including the following steps: S1. According to the mass ratio of polylactic acid, modified biomass fiber, compatibilizer, auxiliary agent and water being 100:35:10.5:5:20, polylactic acid, modified biomass fiber, starch, auxiliary agent (including antioxidant and plasticizer with a mass ratio of 1:1) and water are stirred and mixed at 450 r / min for 50 min to form a mixture; S2. The mixture is put into a mold and hot-pressed into shape at a temperature of 155 °C and a pressure of 5.5 MPa for 30 min to obtain the non-grain biomass fully degradable packaging material.

[0030] The modified biomass fiber in the step S1 is prepared by the following method: (1) According to the mass ratio of corn straw and rice straw being 1.2:1, after crushing corn straw and rice straw, they are stirred and mixed at 600 r / min for 30 min, and biomass fiber is prepared by steam explosion, and the explosion temperature is 285 °C; (2) According to the mass ratio of biomass fiber, 1-butyl-3-methylimidazolium chloride, citric anhydride, triethylamine and pentaerythritol being 10:35:2.5:0.65:1.5, the biomass fiber and 1-butyl-3-methylimidazolium chloride are stirred and mixed at 500 r / min for 30 min, citric anhydride and triethylamine are added, the temperature is raised to 85 °C, stirred and mixed at 400 r / min for 1.2 h, then pentaerythritol is added, stirred and mixed at 400 r / min for 1 h, centrifuged at 10000 r / min for 15 min, washed with water and dried at 42 °C for 1.2 h to obtain a fiber product; (3) According to the mass ratio of the fiber product, gallic acid solution and silane coupling agent solution being 10:3.2:1.2, the fiber product and gallic acid solution (prepared by stirring and mixing gallic acid and water at a mass ratio of 1:100 at 500 r / min for 30 min) are stirred and mixed at 400 r / min for 1.2 h, the temperature is controlled at 52 °C, washed with water, dried at 40 °C for 20 min, then the silane coupling agent solution (prepared by stirring and mixing γ-aminopropyltriethoxysilane and absolute ethanol at a mass ratio of 1:50 at 500 r / min for 30 min) is added and stirred and mixed at 400 r / min for 1.3 h, the temperature is controlled at 65 °C, centrifuged at 12000 r / min for 30 min, washed with water and dried at 50 °C for 1.2 h to obtain the modified biomass fiber.

[0031] The compatibilizer is prepared by the following method: 1) According to the mass ratio of nano calcium carbonate suspension to hyaluronic acid solution being 5.5:1.5, mix the nano calcium carbonate suspension (prepared by mixing nano calcium carbonate and absolute ethanol at a mass ratio of 1:20, with an ultrasonic power of 300 W, an ultrasonic frequency of 20 KHz, and ultrasonic dispersion for 30 min) and the hyaluronic acid solution (prepared by mixing hyaluronic acid and water at a mass ratio of 1:10 with stirring at 500 r / min for 30 min) at 400 r / min for 2.5 h, control the temperature at 45 °C, cool, centrifuge at 8000 r / min for 20 min, wash with deionized water, and dry at 45 °C for 10 h to obtain modified nano calcium carbonate; 2) Mix the modified nano calcium carbonate with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the modified nano calcium carbonate), perform ultrasonic dispersion at an ultrasonic power of 500 W, an ultrasonic frequency of 20 KHz for 30 min to form a modified nano calcium carbonate suspension. According to the mass ratio of the modified nano calcium carbonate suspension, dimethyl itaconate, and potassium persulfate being 8.5:2:0.1, add dimethyl itaconate to the modified nano calcium carbonate suspension, stir and mix at 500 r / min for 40 min, then add potassium persulfate, and under nitrogen protection, continue to stir and mix at 300 r / min for 4.5 h, control the temperature at 65 °C, cool, centrifuge at 10000 r / min for 30 min, wash with deionized water, and dry at 45 °C for 2 h to obtain the functional substance; 3) Mix the functional substance with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the functional substance), perform ultrasonic dispersion at an ultrasonic power of 400 W, an ultrasonic frequency of 25 KHz for 30 min to form a functional substance solution. According to the mass ratio of the functional substance solution to the sodium alginate solution being 1.2:1, add the sodium alginate solution (prepared by mixing sodium alginate and water at a mass ratio of 1:10 with stirring at 500 r / min for 30 min) to the functional substance solution, stir and mix at 400 r / min for 1.2 h, wash with deionized water, and freeze-dry at -20 °C for 1.5 h to obtain the compatibilizer.

[0032] Example 3 A preparation method of a non-grain biomass fully degradable packaging material specifically includes the following steps: S1. According to the mass ratio of polylactic acid, modified biomass fiber, compatibilizer, additive, and water being 100:40:11:5:20, mix polylactic acid, modified biomass fiber, starch, additive (including antioxidant and plasticizer with a mass ratio of 1:1) and water at 500 r / min for 50 min to form a mixture; S2. Put the mixture into a mold for hot pressing and forming at a temperature of 160 °C, a pressure of 6 MPa, and hot press for 30 min to obtain the non-grain biomass fully degradable packaging material.

[0033] The modified biomass fiber in the step S1 is prepared by the following method: (1)Mix corn straw and rice straw after pulverizing them at a mass ratio of 1.5:1, and stir and mix them at 600 r / min for 30 min. Prepare biomass fibers by steam explosion, with the explosion temperature being 290 °C; (2)Mix biomass fibers, 1-butyl-3-methylimidazolium chloride, citric anhydride, triethylamine, and pentaerythritol at a mass ratio of 10:40:3:0.7:2. Stir and mix biomass fibers and 1-butyl-3-methylimidazolium chloride at 500 r / min for 30 min. Add citric anhydride and triethylamine, heat up to 90 °C, stir and mix at 400 r / min for 1.5 h, then add pentaerythritol, stir and mix at 400 r / min for 1 h, centrifuge at 10000 r / min for 20 min, wash with water, and dry at 45 °C for 1.5 h to obtain fiber products; (3)Mix fiber products, gallic acid solution, and silane coupling agent solution at a mass ratio of 10:3.5:1.5. Stir and mix fiber products and gallic acid solution (prepared by mixing gallic acid and water at a mass ratio of 1:100 and stirring at 500 r / min for 30 min) at 400 r / min for 1.5 h, control the temperature at 55 °C, wash with water, dry at 40 °C for 20 min, then add silane coupling agent solution (prepared by mixing γ-aminopropyltriethoxysilane and absolute ethanol at a mass ratio of 1:50 and stirring at 500 r / min for 30 min), stir and mix at 400 r / min for 1.5 h, control the temperature at 70 °C, centrifuge at 12000 r / min for 30 min, wash with water, and dry at 50 °C for 1.5 h to obtain modified biomass fibers.

[0034] The compatibilizer is prepared by the following method: 1)Mix nano-calcium carbonate suspension and hyaluronic acid solution at a mass ratio of 6:2. Nano-calcium carbonate suspension (prepared by mixing nano-calcium carbonate and absolute ethanol at a mass ratio of 1:20, with ultrasonic power of 300 W, ultrasonic frequency of 20 KHz, and ultrasonic dispersion for 30 min) and hyaluronic acid solution (prepared by mixing hyaluronic acid and water at a mass ratio of 1:10 and stirring at 500 r / min for 30 min) are stirred and mixed at 400 r / min for 3 h, control the temperature at 50 °C, cool, centrifuge at 8000 r / min for 20 min, wash with deionized water, and dry at 50 °C for 10 h to obtain modified nano-calcium carbonate; 2) Mix the modified nano calcium carbonate with absolute ethanol (the dosage of absolute ethanol is 10 times the mass of the modified nano calcium carbonate), and form a suspension of modified nano calcium carbonate by ultrasonic dispersion for 30 min at an ultrasonic power of 500 W and an ultrasonic frequency of 20 KHz. According to the mass ratio of 9:2:0.1 of the suspension of modified nano calcium carbonate, dimethyl itaconate and potassium persulfate, add dimethyl itaconate to the suspension of modified nano calcium carbonate, stir and mix at 500 r / min for 40 min, then add potassium persulfate, and continue to stir and mix at 300 r / min for 5 h under nitrogen protection, control the temperature at 70 °C, cool, centrifuge at 10000 r / min for 30 min, wash with deionized water, and dry at 45 °C for 2 h to obtain the functional material; 3) Mix the functional material with absolute ethanol (the dosage of absolute ethanol is 10 times the mass of the functional material), and form a solution of the functional material by ultrasonic dispersion for 30 min at an ultrasonic power of 400 W and an ultrasonic frequency of 25 KHz. According to the mass ratio of 1.5:1 of the solution of the functional material and the sodium alginate solution, add the sodium alginate solution (prepared by stirring and mixing sodium alginate and water at a mass ratio of 1:10 at 500 r / min for 30 min) to the solution of the functional material, stir and mix at 400 r / min for 1.5 h, wash with deionized water, and freeze-dry at -20 °C for 2 h to obtain the compatibilizer.

[0035] Example 4 A preparation method of a non-grain biomass fully degradable packaging material specifically includes the following steps: S1. According to the mass ratio of 100:45:11.5:5:20 of polylactic acid, modified biomass fiber, compatibilizer, auxiliary agent and water, mix polylactic acid, modified biomass fiber, starch, auxiliary agent (including antioxidant and plasticizer with a mass ratio of 1:1) and water at 550 r / min for 50 min to form a mixture; S2. Put the mixture into a mold and hot-press it into shape at a temperature of 165 °C and a pressure of 6.5 MPa for 30 min to obtain the non-grain biomass fully degradable packaging material.

[0036] The modified biomass fiber in the step S1 is prepared by the following method: (1) According to the mass ratio of 1.8:1 of corn straw and rice straw, after crushing corn straw and rice straw, stir and mix at 600 r / min for 30 min, and prepare biomass fiber by steam explosion, and the explosion temperature is 295 °C; (2)Mix the biomass fiber and 1-butyl-3-methylimidazolium chloride at a mass ratio of 10:45:3.5:0.75:2.5. Stir and mix them at 500 r / min for 30 min. Add citric anhydride and triethylamine, heat up to 95 °C, stir and mix at 400 r / min for 1.8 h. Then add pentaerythritol and stir and mix at 400 r / min for 1 h. Centrifuge at 10000 r / min for 25 min, wash with water, and dry at 48 °C for 1.8 h to obtain the fiber product. (3)Mix the fiber product and gallic acid solution at a mass ratio of 10:3.8:1.8. The gallic acid solution is prepared by mixing gallic acid and water at a mass ratio of 1:100 and stirring and mixing at 500 r / min for 30 min. Stir and mix them at 400 r / min for 1.8 h, control the temperature at 58 °C, wash with water, dry at 40 °C for 20 min. Then add the silane coupling agent solution (prepared by mixing γ-aminopropyltriethoxysilane and absolute ethanol at a mass ratio of 1:50 and stirring and mixing at 500 r / min for 30 min), stir and mix at 400 r / min for 1.8 h, control the temperature at 75 °C, centrifuge at 12000 r / min for 30 min, wash with water, and dry at 50 °C for 1.8 h to obtain the modified biomass fiber.

[0037] The compatibilizer is prepared by the following method: 1) Mix the nano calcium carbonate suspension and hyaluronic acid solution at a mass ratio of 6.5:2.5. The nano calcium carbonate suspension is prepared by mixing nano calcium carbonate and absolute ethanol at a mass ratio of 1:20, under ultrasonic power of 300 W, ultrasonic frequency of 20 KHz, and ultrasonic dispersion for 30 min. The hyaluronic acid solution is prepared by mixing hyaluronic acid and water at a mass ratio of 1:10 and stirring and mixing at 500 r / min for 30 min. Stir and mix them at 400 r / min for 3.5 h, control the temperature at 55 °C, cool, centrifuge at 8000 r / min for 20 min, wash with deionized water, and dry at 55 °C for 10 h to obtain the modified nano calcium carbonate. 2) Mix the modified nano calcium carbonate with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the modified nano calcium carbonate), and form a modified nano calcium carbonate suspension under ultrasonic power of 500 W, ultrasonic frequency of 20 KHz, and ultrasonic dispersion for 30 min. Mix the modified nano calcium carbonate suspension, dimethyl itaconate and potassium persulfate at a mass ratio of 9.5:2:0.1. Add dimethyl itaconate to the modified nano calcium carbonate suspension, stir and mix at 500 r / min for 40 min, then add potassium persulfate, and continue to stir and mix at 300 r / min for 5.5 h under nitrogen protection, control the temperature at 75 °C, cool, centrifuge at 10000 r / min for 30 min, wash with deionized water, and dry at 45 °C for 2 h to obtain the functional product. 3) Mix the functional substance with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the functional substance), and perform ultrasonic dispersion at an ultrasonic power of 400 W, an ultrasonic frequency of 25 KHz for 30 min to form a functional substance solution. According to the mass ratio of the functional substance solution to the sodium alginate solution being 1.7:1, add the sodium alginate solution (prepared by stirring and mixing sodium alginate and water at a mass ratio of 1:10 at 500 r / min for 30 min) to the functional substance solution, stir and mix at 400 r / min for 1.8 h, wash with deionized water, and freeze-dry at -20 °C for 2.5 h to obtain the compatibilizer.

[0038] Example 5 A preparation method of a non-grain biomass fully degradable packaging material specifically includes the following steps: S1. According to the mass ratio of polylactic acid, modified biomass fiber, compatibilizer, auxiliary agent and water being 100:50:12:5:20, stir and mix polylactic acid, modified biomass fiber, starch, auxiliary agent (including antioxidant and plasticizer with a mass ratio of 1:1) and water at 600 r / min for 50 min to form a mixture; S2. Put the mixture into a mold for hot pressing and forming at a temperature of 170 °C, a pressure of 7 MPa, and hot press for 30 min to obtain the non-grain biomass fully degradable packaging material.

[0039] The modified biomass fiber in step S1 is prepared by the following method: (1) According to the mass ratio of corn straw to rice straw being 2:1, after crushing corn straw and rice straw, stir and mix at 600 r / min for 30 min, and prepare biomass fiber by steam explosion, with the explosion temperature being 300 °C; (2) According to the mass ratio of biomass fiber, 1-butyl-3-methylimidazolium chloride, citric anhydride, triethylamine and pentaerythritol being 10:50:4:0.8:3, stir and mix biomass fiber and 1-butyl-3-methylimidazolium chloride at 500 r / min for 30 min, add citric anhydride and triethylamine, heat up to 100 °C, stir and mix at 400 r / min for 2 h, then add pentaerythritol, stir and mix at 400 r / min for 1 h, centrifuge at 10000 r / min for 30 min, wash with water, and dry at 50 °C for 2 h to obtain a fiber product; (3) According to the mass ratio of the fiber product, gallic acid solution and silane coupling agent solution being 10:4:2, mix the fiber product with the gallic acid solution (prepared by mixing gallic acid and water at a mass ratio of 1:100 with stirring at 500 r / min for 30 min) at 400 r / min for 2 h, control the temperature at 60 °C, wash with water, dry at 40 °C for 20 min, then add the silane coupling agent solution (prepared by mixing γ-aminopropyltriethoxysilane and absolute ethanol at a mass ratio of 1:50 with stirring at 500 r / min for 30 min) and mix at 400 r / min for 2 h, control the temperature at 80 °C, centrifuge at 12000 r / min for 30 min, wash with water and then dry at 50 °C for 2 h to obtain the modified biomass fiber.

[0040] The compatibilizer is prepared by the following method: 1) According to the mass ratio of the nano-calcium carbonate suspension and the hyaluronic acid solution being 7:3, mix the nano-calcium carbonate suspension (prepared by mixing nano-calcium carbonate and absolute ethanol at a mass ratio of 1:20 with ultrasonic dispersion at an ultrasonic power of 300 W, an ultrasonic frequency of 20 KHz for 30 min) and the hyaluronic acid solution (prepared by mixing hyaluronic acid and water at a mass ratio of 1:10 with stirring at 500 r / min for 30 min) at 400 r / min for 4 h, control the temperature at 60 °C, cool, centrifuge at 8000 r / min for 20 min, wash with deionized water, and dry at 60 °C for 10 h to obtain the modified nano-calcium carbonate; 2) Mix the modified nano-calcium carbonate with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the modified nano-calcium carbonate), and form a modified nano-calcium carbonate suspension with ultrasonic dispersion at an ultrasonic power of 500 W and an ultrasonic frequency of 20 KHz for 30 min. According to the mass ratio of the modified nano-calcium carbonate suspension, dimethyl itaconate and potassium persulfate being 10:2:0.1, add dimethyl itaconate to the modified nano-calcium carbonate suspension, mix at 500 r / min for 40 min, then add potassium persulfate, and continue to mix at 300 r / min for 6 h under nitrogen protection, control the temperature at 80 °C, cool, centrifuge at 10000 r / min for 30 min, wash with deionized water, and dry at 45 °C for 2 h to obtain the functional substance; 3) Mix the functional substance with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the functional substance), and form a functional solution with ultrasonic dispersion at an ultrasonic power of 400 W and an ultrasonic frequency of 25 KHz for 30 min. According to the mass ratio of the functional substance solution and the sodium alginate solution being 2:1, add the sodium alginate solution (prepared by mixing sodium alginate and water at a mass ratio of 1:10 with stirring at 500 r / min for 30 min) to the functional substance solution, mix at 400 r / min for 2 h, wash with deionized water, and freeze-dry at -20 °C for 3 h to obtain the compatibilizer.

[0041] Comparative Example 1 Comparative Example 1 is the same as Example 1, except that when preparing the modified biomass fiber, the biomass fiber reacts with gallic acid solution and silane coupling agent solution first, and the specific steps are as follows: The modified biomass fiber in step S1 is prepared by the following method: (1) According to the mass ratio of corn straw to rice straw being 1:1, after crushing corn straw and rice straw, stir and mix them at 600 r / min for 30 min, and prepare biomass fiber by steam explosion. The explosion temperature is 280 °C; (2) According to the mass ratio of biomass fiber, gallic acid solution and silane coupling agent solution being 10:3:1, stir and mix the biomass fiber with the gallic acid solution (prepared by stirring and mixing gallic acid and water at a mass ratio of 1:100 at 500 r / min for 30 min) at 400 r / min for 1 h, control the temperature at 50 °C, wash with water, dry at 40 °C for 20 min, then add the silane coupling agent solution (prepared by stirring and mixing γ-aminopropyltriethoxysilane and absolute ethanol at a mass ratio of 1:50 at 500 r / min for 30 min), stir and mix at 400 r / min for 1 h, control the temperature at 60 °C, centrifuge at 12000 r / min for 30 min, wash with water, and then dry at 50 °C for 1 h to obtain a fiber product; (3) According to the mass ratio of fiber product, 1-butyl-3-methylimidazolium chloride, citric anhydride, and triethylamine being 10:30:2:0.6, stir and mix the fiber product with 1-butyl-3-methylimidazolium chloride at 500 r / min for 30 min, add citric anhydride and triethylamine, raise the temperature to 80 °C, stir and mix at 400 r / min for 1 h, centrifuge at 10000 r / min for 10 min, then add pentaerythritol, stir and mix at 400 r / min for 1 h, wash with water, and dry at 40 °C for 1 h to obtain the modified biomass fiber.

[0042] Comparative Example 2 Comparative Example 2 is the same as Example 1, except that when preparing the modified biomass fiber, the biomass fiber reacts with citric anhydride, triethylamine, and pentaerythritol simultaneously, and the specific steps are as follows: The modified biomass fiber in step S1 is prepared by the following method: (1) According to the mass ratio of corn straw to rice straw being 1:1, after crushing corn straw and rice straw, stir and mix them at 600 r / min for 30 min, and prepare biomass fiber by steam explosion. The explosion temperature is 280 °C; (2)Mix biomass fiber, 1-butyl-3-methylimidazolium chloride, citric anhydride, triethylamine and pentaerythritol in a mass ratio of 10:30:2:0.6:1. Stir and mix biomass fiber and 1-butyl-3-methylimidazolium chloride at 500 r / min for 30 min. Add citric anhydride, triethylamine and pentaerythritol, heat up to 80 °C, stir and mix at 400 r / min for 1 h, centrifuge at 10000 r / min for 10 min, wash with water and then dry at 40 °C for 1 h to obtain fiber product; (3)Mix fiber product, gallic acid solution and silane coupling agent solution in a mass ratio of 10:3:1. Stir and mix fiber product and gallic acid solution (prepared by mixing gallic acid and water in a mass ratio of 1:100 at 500 r / min for 30 min) at 400 r / min for 1 h, control the temperature at 50 °C, wash with water, dry at 40 °C for 20 min, then add silane coupling agent solution (prepared by mixing γ-aminopropyltriethoxysilane and absolute ethanol in a mass ratio of 1:50 at 500 r / min for 30 min) and stir and mix at 400 r / min for 1 h, control the temperature at 60 °C, centrifuge at 12000 r / min for 30 min, wash with water and then dry at 50 °C for 1 h to obtain modified biomass fiber.

[0043] Comparative Example 3 Comparative Example 3 is the same as Example 1, except that nano-calcium carbonate is not modified during the preparation of the compatibilizer, and the specific process is as follows: The compatibilizer is prepared by the following method: 1) Mix nano-calcium carbonate and absolute ethanol (the dosage of absolute ethanol is 10 times the mass of nano-calcium carbonate) in a mass ratio of nano-calcium carbonate suspension and sodium alginate solution of 1:1. Under ultrasonic power of 500 W and ultrasonic frequency of 20 KHz, ultrasonically disperse for 30 min to form nano-calcium carbonate suspension. Add sodium alginate solution (prepared by mixing sodium alginate and water in a mass ratio of 1:10 at 500 r / min for 30 min), stir and mix at 400 r / min for 1 h, wash with deionized water and freeze-dry at -20 °C for 1 h to obtain the composite; 2) Mix the composite and absolute ethanol (the dosage of absolute ethanol is 10 times the mass of the composite) to form a composite solution under ultrasonic power of 400 W and ultrasonic frequency of 25 KHz by ultrasonically dispersing for 30 min. According to the mass ratio of the composite solution, dimethyl itaconate and potassium persulfate of 8:2:0.1, add dimethyl itaconate to the composite solution, stir and mix at 500 r / min for 40 min, then add potassium persulfate, under nitrogen protection, continue to stir and mix at 300 r / min for 4 h, control the temperature at 60 °C, cool, centrifuge at 10000 r / min for 30 min, wash with deionized water and dry at 45 °C for 2 h to obtain the compatibilizer.

[0044] Comparative Example 4 Comparative Example 4 is the same as Example 1, except that modified nano-calcium carbonate is not added during the preparation of the compatibilizer, and the specific process is as follows: The compatibilizer is prepared by the following method: According to the mass ratio of sodium alginate solution, dimethyl itaconate and potassium persulfate being 8:2:0.1, add dimethyl itaconate to the sodium alginate solution (prepared by stirring and mixing sodium alginate and water at a mass ratio of 1:10 at 500 r / min for 30 min) and stir and mix at 500 r / min for 40 min. Then add potassium persulfate, and under nitrogen protection, continue to stir and mix at 300 r / min for 4 h, control the temperature at 60 °C, cool, centrifuge at 10000 r / min for 30 min, wash with deionized water, and dry at 45 °C for 2 h to obtain the compatibilizer.

[0045] Comparative Example 5 Comparative Example 5 is the same as Example 1, except that sodium alginate is first compounded with modified nano-calcium carbonate and then grafted with dimethyl itaconate during the preparation of the compatibilizer, and the specific process is as follows: The compatibilizer is prepared by the following method: 1) According to the mass ratio of nano-calcium carbonate suspension and hyaluronic acid solution being 5:1, mix the nano-calcium carbonate suspension (prepared by ultrasonic dispersion of nano-calcium carbonate and absolute ethanol at a mass ratio of 1:20 with an ultrasonic power of 300 W, an ultrasonic frequency of 20 kHz for 30 min) and the hyaluronic acid solution (prepared by stirring and mixing hyaluronic acid and water at a mass ratio of 1:10 at 500 r / min for 30 min) and stir and mix at 400 r / min for 2 h, control the temperature at 40 °C, cool, centrifuge at 8000 r / min for 20 min, wash with deionized water, and dry at 40 °C for 10 h to obtain modified nano-calcium carbonate; 2) According to the mass ratio of the modified nano-calcium carbonate suspension and the sodium alginate solution being 1:1, mix the modified nano-calcium carbonate with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the modified nano-calcium carbonate), and form a modified nano-calcium carbonate suspension by ultrasonic dispersion at an ultrasonic power of 500 W and an ultrasonic frequency of 20 kHz for 30 min. Add the sodium alginate solution (prepared by stirring and mixing sodium alginate and water at a mass ratio of 1:10 at 500 r / min for 30 min), stir and mix at 400 r / min for 1 h, wash with deionized water, and freeze-dry at -20 °C for 1 h to obtain the composite; 3) Mix the composite with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the composite), and form a composite solution by ultrasonic dispersion for 30 min at an ultrasonic power of 400 W and an ultrasonic frequency of 25 KHz. According to the mass ratio of the composite solution, dimethyl itaconate, and potassium persulfate of 8:2:0.1, add dimethyl itaconate to the composite solution, stir and mix at 500 r / min for 40 min, then add potassium persulfate, and continue to stir and mix at 300 r / min for 4 h under nitrogen protection. Control the temperature at 60 °C, cool, centrifuge at 10000 r / min for 30 min, wash with deionized water, and dry at 45 °C for 2 h to obtain the compatibilizer.

[0046] Comparative Example 6 Comparative Example 6 is the same as Example 1, except that when preparing the compatibilizer, the modified nano-calcium carbonate is not grafted with dimethyl itaconate, and the specific method is as follows: The compatibilizer is prepared by the following method: 1) According to the mass ratio of the nano-calcium carbonate suspension and the hyaluronic acid solution of 5:1, mix the nano-calcium carbonate suspension (prepared by mixing nano-calcium carbonate and absolute ethanol at a mass ratio of 1:20 by ultrasonic dispersion for 30 min at an ultrasonic power of 300 W and an ultrasonic frequency of 20 KHz) and the hyaluronic acid solution (prepared by mixing hyaluronic acid and water at a mass ratio of 1:10 by stirring and mixing at 500 r / min for 30 min) at 400 r / min for 2 h. Control the temperature at 40 °C, cool, centrifuge at 8000 r / min for 20 min, wash with deionized water, and dry at 40 °C for 10 h to obtain the modified nano-calcium carbonate; 2) According to the mass ratio of the modified nano-calcium carbonate suspension and the sodium alginate solution of 1:1, mix the modified nano-calcium carbonate with absolute ethanol (the amount of absolute ethanol is 10 times the mass of the modified nano-calcium carbonate), and form a modified nano-calcium carbonate suspension by ultrasonic dispersion for 30 min at an ultrasonic power of 500 W and an ultrasonic frequency of 20 KHz. Add the sodium alginate solution (prepared by mixing sodium alginate and water at a mass ratio of 1:10 by stirring and mixing at 500 r / min for 30 min), stir and mix at 400 r / min for 1 h, wash with deionized water, and freeze-dry at -20 °C for 1 h to obtain the compatibilizer.

[0047] Performance Test Comprehensive performance tests were carried out on the non-grain biomass fully biodegradable packaging materials prepared in Examples 1-5 and Comparative Examples 1-6.

[0048] 1. Mechanical Property Test According to GB / T 1040.1-2018 "Determination of Tensile Properties of Plastics - Part 1: General Principles", tensile strength tests were carried out on the non-grain biomass fully biodegradable packaging materials prepared in Examples 1-5 and Comparative Examples 1-6, and the results are shown in Table 1.

[0049] According to GB / T 9341-2008 "Determination of Flexural Properties of Plastics", the flexural strength of the non-grain biomass fully biodegradable packaging materials prepared in Examples 1-5 and Comparative Examples 1-6 was tested, and the results are shown in Table 1.

[0050] 2. Waterproofness test According to GB / T 1034-2008 "Test Method for Water Absorption of Plastics", the water resistance of the non-grain biomass fully biodegradable packaging materials prepared in Examples 1-5 and Comparative Examples 1-6 was tested, and the results are shown in Table 1.

[0051] 3. Degradability test According to GB / T 19277.1-2011 "Determination of the Ultimate Aerobic Biodegradation Ability of Materials under Controlled Composting Conditions - Method by Measuring the Released Carbon Dioxide - Part 1: General Method", the biodegradability was detected, and the results are shown in Table 1.

[0052] Table 1

[0053] As can be seen from Table 1, compared with Comparative Examples 1-6, the non-grain biomass fully biodegradable packaging materials prepared in Examples 1-5 have better mechanical properties and stronger waterproofness. Among them, by comparing Comparative Examples 1-2 with Example 1, it can be seen that changing the preparation raw materials and processes of the modified biomass fibers will reduce the tensile strength and flexural strength of the packaging materials and increase the water absorption rate, indicating that the prior reaction of biomass fibers with citric anhydride and pentaerythritol can improve the mechanical properties and water resistance of the biomass fibers, and gallic acid can form active sites on the surface of the fiber products, improving the combination of the fiber products with silane coupling agents and other raw materials, and further improving the mechanical properties of the packaging materials. By comparing Comparative Examples 3-6 with Example 1, it can be seen that changing the preparation raw materials and processes of the compatibilizer will reduce the mechanical properties and waterproofness of the packaging materials, indicating that the modification of nano calcium carbonate, grafting dimethyl itaconate on the modified nano calcium carbonate first and then compounding with sodium alginate can significantly enhance the interfacial bonding force between polylactic acid and modified biomass fibers, reduce the surface energy, and thus improve the waterproofness and mechanical properties of the packaging materials. The non-grain biomass fully biodegradable packaging material prepared in this application has excellent mechanical properties and waterproofness, high biodegradability, is environmentally friendly, and has important application value.

[0054] This specific embodiment is only an explanation of this application and does not limit this application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of this application, they are protected by the patent law.

Claims

1. A preparation method of a non-grain biomass fully degradable packaging material, characterized in that, The preparation method of the non-grain biomass fully degradable packaging material specifically includes the following steps: S1. Stir and mix polylactic acid, modified biomass fiber, compatibilizer, auxiliary agent and water to form a mixture; S2. Put the mixture into a mold and hot-press it to obtain the non-grain biomass fully degradable packaging material.

2. The preparation method of a non-grain biomass fully degradable packaging material according to claim 1, characterized in that, In the step S1, the mass ratio of polylactic acid, modified biomass fiber, compatibilizer, auxiliary agent and water is 100:30 - 50:10 - 12:5:

20.

3. The preparation method of a non-grain biomass fully biodegradable packaging material according to claim 1, characterized in that, The modified biomass fiber in the step S1 is prepared by the following method: (1) After crushing corn straw and rice straw, stir and mix them evenly, and prepare biomass fiber by steam explosion; (2) Stir and mix the biomass fiber with 1-butyl-3-methylimidazolium chloride, add citric anhydride and triethylamine, raise the temperature, stir and mix, then add pentaerythritol, stir and mix, centrifuge, wash with water and dry to obtain a fiber product; (3) Stir and mix the fiber product with gallic acid solution, wash with water and dry, then add silane coupling agent solution, stir and mix, centrifuge, wash with water and dry to obtain the modified biomass fiber.

4. The preparation method of a non-grain biomass fully biodegradable packaging material according to claim 3, characterized in that, In the step (2), the mass ratio of biomass fiber, 1-butyl-3-methylimidazolium chloride, citric anhydride, triethylamine and pentaerythritol is 10:30 - 50:2 - 4:0.6 - 0.8:1 - 3.

5. The preparation method of a non-grain biomass fully biodegradable packaging material according to claim 3, wherein, In the step (3), the mass ratio of the fiber product, gallic acid solution and silane coupling agent solution is 10:3 - 4:1 - 2.

6. The preparation method of a non-grain biomass fully degradable packaging material according to claim 1, characterized in that, The compatibilizer is prepared by the following method: 1) Stir and mix nano calcium carbonate suspension and hyaluronic acid solution, control the temperature, cool and centrifuge, wash with deionized water and dry to obtain modified nano calcium carbonate; 2) Mix the modified nano calcium carbonate with absolute ethanol, ultrasonically disperse to form a modified nano calcium carbonate suspension, add dimethyl itaconate to the modified nano calcium carbonate suspension, stir and mix, then add potassium persulfate, under nitrogen protection, continue to stir and mix, control the temperature, cool and centrifuge, wash with deionized water and dry to obtain a functional substance; 3) Mix the functional substance with absolute ethanol, ultrasonically disperse to form a functional substance solution, add sodium alginate solution to the functional substance solution, stir and mix, wash with deionized water and freeze-dry to obtain the compatibilizer.

7. The preparation method of a non-grain biomass fully biodegradable packaging material according to claim 6, characterized in that, In the step 1), the mass ratio of nano calcium carbonate suspension and hyaluronic acid solution is 5 - 7:1 - 3.

8. The preparation method of a non-grain biomass fully biodegradable packaging material according to claim 6, characterized in that, In the step 2), the mass ratio of the modified nano calcium carbonate suspension, dimethyl itaconate and potassium persulfate is 8 - 10:2:0.

1.

9. The preparation method of a non-grain biomass fully degradable packaging material according to claim 1, characterized in that, In the step S1, the auxiliary agent is at least one of antioxidant, plasticizer and lubricant.

10. A non-grain biomass fully degradable packaging material, characterized in that, It is prepared by the preparation method of a non-grain biomass fully degradable packaging material according to any one of claims 1 - 9.

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