Polyethylene clean film, packaging bag and preparation method of polyethylene clean film

Abstract

The invention discloses a polyethylene clean film, a packaging bag and a preparation method thereof, and relates to the technical field of polyethylene packaging bags, the polyethylene clean film comprises the following components by weight: 75-90 parts of low density polyethylene, 4.5-6 parts of a bacteriostatic agent, 2.5-3.6 parts of functionalized graphene oxide, and 2-3.2 parts of modified nano zinc oxide. According to the polyethylene clean film, the packaging bag and the preparation method of the polyethylene clean film, the bacteriostatic agent and the polyethylene chain interact to form hydrogen bonds or physical entanglement, so that molecular chains are combined more tightly, the tensile strength of the packaging bag is improved, and the risk of breakage is reduced; due to the addition of the bacteriostatic agent, the flexibility and the sliding property of a molecular chain are improved, energy can be dissipated through chain segment movement when the packaging bag is subjected to external force, the impact resistance and the flexibility are improved, and the possibility of embrittlement is reduced; the bacteriostatic agent can also form a barrier layer in a polyethylene matrix or disorganize a gas diffusion channel, increase the tortuosity of the gas diffusion channel and reduce the permeability of gases such as oxygen and carbon dioxide.

Description

Technical Field

[0001] The invention relates to the technical field of polyethylene packaging bags, in particular to a polyethylene clean film, a packaging bag and a preparation method thereof. Background Art

[0002] The Chinese patent with publication number CN112724494A discloses a polyethylene material for food packaging bags, the raw materials of which include by weight: 80-100 parts of polyethylene, 10-20 parts of impact modifier, 8-10 parts of filler, 0.1-0.3 parts of stearic acid, 2-3 parts of compatibilizer, wherein the filler is talcum powder, organic nano-montmorillonite and modified graphene; the invention has good mechanical properties and antibacterial properties. However, the antibacterial properties of the packaging material prepared by the above technical solution need to be improved; for this reason, the present invention provides a polyethylene clean film, a packaging bag and a preparation method thereof to solve the above problems. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a polyethylene clean film, a packaging bag and a preparation method thereof, which solve the problems mentioned in the above background technology.

[0004] To achieve the above objectives, the present invention is implemented by the following technical scheme: a polyethylene clean film and packaging bag, comprising the following components in parts by weight: 75-90 parts of low-density polyethylene, 4.5-6 parts of antibacterial agent, 2.5-3.6 parts of functionalized graphene oxide, and 2-3.2 parts of modified nano zinc oxide; The preparation method of the modified nano zinc oxide is: S1. Pour 3-5 g of nano zinc oxide into 25-40 mL of anhydrous ethanol, stir magnetically for 10-15 min, and then perform ultrasonic dispersion treatment for 20-30 min; S2, add 1.5-3g of sorbic acid, raise the temperature to 45-60°C, and stir to react for 20-30min; S3. After the reaction is completed, the precipitate is washed by centrifugation with anhydrous ethanol for 3-4 times, and then placed in a vacuum drying oven at 50-60° C. and dried for 11-13 hours to obtain modified nano zinc oxide.

[0005] Preferably, the preparation method of the antibacterial agent is: 1) Pour 3.5-5g of chitosan into 10-15mL of 10% hydrochloric acid solution and stir until completely dissolved; 2) Add anhydrous ethanol to precipitate, filter the precipitate under reduced pressure, wash it with ethanol 2-4 times, and then dry it in a vacuum drying oven at 55-70°C for 6-8 hours; 3) Pour in 25-40 mL of distilled water, stir until completely dissolved, then add 2-3.6 g of dicyandiamide, and heat to 110-120 ° C under stirring, and react for 2-2.5 hours; 4) After the reaction is completed, cool to room temperature, filter under reduced pressure, wash with anhydrous ethanol for precipitation, and then purify the precipitate by acetone Soxhlet extraction for 22-24 hours. Finally, dry in a vacuum drying oven at 60-70°C for 4-5 hours and grind to obtain the antibacterial agent.

[0006] Preferably, the preparation method of the functionalized graphene oxide is: Pour 0.4-1.5 g of modified graphene oxide into 60-70 mL of anhydrous ethanol, ultrasonically treat for 50-65 min, add 4-6.5 g of hydrazine hydrate, heat to 55-65 ° C, and react under magnetic stirring for 10-12 h at this temperature, then filter, wash alternately with anhydrous ethanol and deionized water 3-5 times, and finally place in a drying oven at 50-60 ° C to dry for 1.5-2 h to obtain functionalized graphene oxide.

[0007] Preferably, the preparation method of the modified graphene oxide is: (1) 0.4-1 g of graphene oxide and 50-60 mL of anhydrous ethanol were mixed, and after ultrasonic treatment for 35-50 min, 10% ammonia water was added dropwise, and the pH value of the solution was adjusted to 2.6-3.2 to prepare solution A; (2) Mix 1.2-2.5 g of KH560 with 50-60 mL of 95% ethanol and perform ultrasonic treatment for 45-60 min to prepare solution B; (3) Under stirring conditions, slowly add solution B to solution A, raise the temperature to 45-60°C, and react with magnetic stirring for 10-12 hours; (4) Filter, wash alternately with anhydrous ethanol and deionized water for 3-5 times, dry in a drying oven at 55-65°C for 1.5-2h, and finally grind to obtain modified graphene oxide.

[0008] Preferably, in S1, the preparation method of nano zinc oxide is: S11, pour 0.05-0.07 mol of zinc acetate dihydrate and 0.075-0.095 mol of citric acid into deionized water, heat the water bath to 60-70°C, and stir for 50-65 minutes; S12, adding ethylene glycol in an equal molar ratio to citric acid, stirring and reacting for 5-8 minutes; S13, add ammonia water dropwise to adjust the pH value of the solution to 7, and continue heating and stirring for 25-35 minutes; S14, first place it in a drying oven at 85-95°C for 4-6 hours to obtain a precursor gel, and then place it in a tubular furnace at 500-550°C for high temperature sintering for 1.5-2 hours to obtain nano zinc oxide.

[0009] A method for preparing a polyethylene clean film and a packaging bag, the specific preparation steps are: Step 1: weigh each component; Step 2: Mix all the components evenly, install a corona impactor on the inner cooling exhaust column of the extrusion blow molding machine, and after the raw materials are melted and plasticized, they enter the die blow molding extrusion cylinder. While blow molding and extrusion, turn on the corona impactor to perform electric shock treatment on the inner film. After cooling, shaping, pulling, winding and bag making processes, polyethylene clean film and packaging bags are obtained.

[0010] Preferably, the voltage of the electric shock is 10,000-15,000 volts.

[0011] Beneficial Effects The present invention provides a polyethylene clean film, a packaging bag and a preparation method thereof. Compared with the prior art, the present invention has the following beneficial effects: (1) The polyethylene clean film, packaging bag and preparation method thereof form hydrogen bonds or physical entanglements through the interaction between the antibacterial agent and the polyethylene chain, so that the molecular chains are more tightly bound, the tensile strength of the packaging bag is improved, and the risk of rupture is reduced; the addition of the antibacterial agent increases the flexibility and sliding property of the molecular chain, so that the packaging bag can dissipate energy through the movement of the chain segments when subjected to external forces, thereby improving the impact resistance and flexibility and reducing the possibility of brittle fracture; the antibacterial agent can also form a barrier layer in the polyethylene matrix or disrupt the gas diffusion channel, increase the tortuosity of the gas diffusion path, and reduce the permeability of gases such as oxygen and carbon dioxide; since chitosan itself has antibacterial properties, adding it to the packaging bag can inhibit the growth and reproduction of microorganisms, extend the shelf life of the packaged food, etc., and maintain quality and safety.

[0012] (2) The polyethylene clean film, packaging bag and preparation method thereof, by adding functionalized graphene oxide, form a good interface bond with the low-density polyethylene molecular chain, withstand greater tensile stress, thereby improving the tensile strength of the packaging bag, while also enabling the packaging bag to maintain good flexibility, not prone to brittle cracking, and improve its impact resistance and durability; the functionalized graphene oxide can form a barrier layer in the low-density polyethylene matrix, increasing the path length and difficulty of gas diffusion, thereby reducing the gas permeability, preventing the items in the packaging bag from getting damp, and extending the shelf life of the items; the functionalized graphene oxide has antibacterial activity, can inhibit the growth and reproduction of bacteria on the surface of the packaging bag, and reduce the contamination of packaged items by microorganisms.

[0013] (3) The polyethylene clean film, packaging bag and preparation method thereof, after the nano zinc oxide is modified by sorbic acid, the two combine to produce a synergistic effect, expand the antibacterial spectrum, have a stronger inhibitory effect on common microorganisms such as Escherichia coli and Staphylococcus aureus, can effectively prevent the growth of microorganisms, and extend the shelf life of packaged food, etc. At the same time, the high specific surface area and activity of nano zinc oxide can slowly release sorbic acid, maintain antibacterial activity for a long time, so that the packaging bag can maintain good antibacterial properties for a long time; the modified nano zinc oxide can be used as a reinforcing filler and evenly dispersed in low-density polyethylene to limit the movement of molecular chains, improve the rigidity and hardness of the packaging bag, and make it more resistant to extrusion during transportation and storage; the modified nano zinc oxide forms a barrier network in the polyethylene matrix, and gas molecules need to bypass the modified nano zinc oxide particles when passing through, which increases the tortuosity of the gas diffusion path and reduces the permeability of gases such as oxygen and carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a comparison chart of the antibacterial activity of Escherichia coli provided by the present invention; Figure 2 This is a comparison chart of the antibacterial effect of Staphylococcus aureus provided by the present invention. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] In the technical scheme, the preparation method of modified graphene oxide is as follows: 0.4 g of graphene oxide and 50 mL of anhydrous ethanol are mixed, ultrasonically treated for 35 minutes, 10% ammonia water is added, and the pH value of the solution is adjusted to 3 to obtain solution A; 1.2 g of KH560 is mixed with 50 mL of ethanol with a mass fraction of 95%, and ultrasonically treated for -60 minutes to obtain solution B; under stirring conditions, solution B is slowly added dropwise to solution A, and the temperature is raised to 45°C, and the reaction is magnetically stirred for 12 hours; filtered, washed alternately with anhydrous ethanol and deionized water for 3 times, placed in a drying oven at 55°C for 2 hours, and finally ground to obtain modified graphene oxide.

[0017] The preparation method of nano zinc oxide is as follows: pour 0.05 mol of zinc acetate dihydrate and 0.075 mol of citric acid into deionized water, heat the water bath to 60°C, and stir for 50 minutes; add ethylene glycol in an equal molar ratio to citric acid, stir and react for 5 minutes; add ammonia water dropwise, adjust the pH value of the solution to 7, continue heating and stirring for 25 minutes; first place it in a drying oven at 85°C for 4 hours to obtain a precursor gel, and then place it in a tubular furnace at 550°C for high temperature sintering for 2 hours to obtain nano zinc oxide.

[0018] Example 1 A method for preparing a polyethylene clean film and a packaging bag, the specific preparation steps are: Step 1, weigh each component: 75g low-density polyethylene, 6g antibacterial agent, 3.6g functionalized graphene oxide, and 3.2g modified nano zinc oxide; The preparation method of the antibacterial agent is as follows: pour 3.5g of chitosan into 10mL of a hydrochloric acid solution with a mass fraction of 10%, and stir until completely dissolved; add anhydrous ethanol for precipitation, filter the precipitate under reduced pressure, wash it twice with ethanol, and then dry it in a vacuum drying oven at 55°C for 6h; pour it into 25mL of distilled water, stir until completely dissolved, then add 2g of dicyandiamide, and heat it to 110°C under stirring conditions, and react for 2h; after the reaction is completed, cool it to room temperature, filter it under reduced pressure, wash it with anhydrous ethanol, and then purify the precipitate by acetone Soxhlet extraction for 22h, and finally dry it in a vacuum drying oven at 60°C for 4h and grind it to obtain the antibacterial agent; The preparation method of functionalized graphene oxide is as follows: 0.4 g of modified graphene oxide is poured into 600 mL of anhydrous ethanol, and after ultrasonic treatment for 50 min, 4 g of hydrazine hydrate is added, and the mixture is heated to 55° C. and reacted with magnetic stirring for 10 h under the temperature condition, and then filtered, and washed alternately with anhydrous ethanol and deionized water for 3 times, and finally dried in a drying oven at 50° C. for 1.5 h to obtain functionalized graphene oxide; The preparation method of modified nano zinc oxide is as follows: 3 g of nano zinc oxide is poured into 25 mL of anhydrous ethanol, magnetically stirred for 10 minutes, and then ultrasonically dispersed for 20 minutes; 1.5 g of sorbic acid is added, the temperature is raised to 45°C, and stirred for reaction for 20 minutes; after the reaction is completed, the anhydrous ethanol is used for centrifugal washing 3 times, and then the precipitate is placed in a vacuum drying oven at 50°C and dried for 11 hours to obtain modified nano zinc oxide; Step 2: Mix all the components evenly, install a corona impactor on the inner cooling exhaust column of the extrusion blow molding machine, and after the raw materials are melted and plasticized, they enter the die blow molding extrusion cylinder. While blow molding and extrusion, turn on the corona impactor to perform 10,000 volt electric shock treatment on the inner film. After cooling, shaping, pulling, winding and bag making processes, polyethylene clean film and packaging bags are obtained.

[0019] Example 2 A method for preparing a polyethylene clean film and a packaging bag, the specific preparation steps are: Step 1, weigh each component: 80g low-density polyethylene, 5.5g antibacterial agent, 3g functionalized graphene oxide, and 2.6g modified nano zinc oxide; The preparation method of the antibacterial agent is as follows: pour 4.2g of chitosan into 12mL of a hydrochloric acid solution with a mass fraction of 10%, and stir until completely dissolved; add anhydrous ethanol for precipitation, filter the precipitate under reduced pressure, wash it with ethanol for 3 times, and then place it in a vacuum drying oven at 60°C for 7h; pour it into 30mL of distilled water, stir until completely dissolved, then add 2.8g of dicyandiamide, and heat it to 115°C under stirring conditions, and react for 2.3h; after the reaction is completed, cool it to room temperature, filter it under reduced pressure, wash it with anhydrous ethanol, and then purify the precipitate by acetone Soxhlet extraction for 23h, and finally dry it in a vacuum drying oven at 65°C for 4.5h and grind it to obtain the antibacterial agent; The preparation method of functionalized graphene oxide is as follows: 1 g of modified graphene oxide is poured into 65 mL of anhydrous ethanol, and after ultrasonic treatment for 60 min, 5.5 g of hydrazine hydrate is added, and the mixture is heated to 60° C. and reacted under magnetic stirring for 11 h at the temperature, and then filtered, and washed alternately with anhydrous ethanol and deionized water for 4 times, and finally dried in a drying oven at 55° C. for 1.8 h to obtain functionalized graphene oxide; The preparation method of modified nano zinc oxide is as follows: 4 g of nano zinc oxide is poured into 30 mL of anhydrous ethanol, magnetically stirred for 12 minutes, and then ultrasonically dispersed for 25 minutes; 2.2 g of sorbic acid is added, the temperature is raised to 50° C., and stirred for reaction for 25 minutes; after the reaction is completed, the anhydrous ethanol is used for centrifugal washing 4 times, and then the precipitate is placed in a vacuum drying oven at 55° C. and dried for 12 hours to obtain modified nano zinc oxide; Step 2: Mix all the components evenly, install a corona impactor on the inner cooling exhaust column of the extrusion blow molding machine, and after the raw materials are melted and plasticized, they enter the die blow molding extrusion cylinder. While blow molding and extrusion, turn on the corona impactor to perform 12,000 volt electric shock treatment on the inner film. After cooling, shaping, pulling, winding and bag making processes, polyethylene clean film and packaging bags are obtained.

[0020] Example 3 A method for preparing a polyethylene clean film and a packaging bag, the specific preparation steps are: Step 1, weigh each component: 90g low-density polyethylene, 4.5g antibacterial agent, 2.5g functionalized graphene oxide, and 2g modified nano zinc oxide; The preparation method of the antibacterial agent is as follows: pour 5g of chitosan into 15mL of a hydrochloric acid solution with a mass fraction of 10%, and stir until completely dissolved; add anhydrous ethanol for precipitation, filter the precipitate under reduced pressure, wash it with ethanol for 4 times, and then dry it in a vacuum drying oven at 70°C for 8h; pour it into 40mL of distilled water, stir until completely dissolved, then add 3.6g of dicyandiamide, and heat it to 120°C under stirring conditions, and react for 2.5h; after the reaction is completed, cool it to room temperature, filter it under reduced pressure, wash it with anhydrous ethanol, and then purify the precipitate by acetone Soxhlet extraction for 24h, and finally dry it in a vacuum drying oven at 70°C for 5h and grind it to obtain the antibacterial agent; The preparation method of functionalized graphene oxide is as follows: 1.5 g of modified graphene oxide is poured into 70 mL of anhydrous ethanol, and after ultrasonic treatment for 65 min, 6.5 g of hydrazine hydrate is added, and the mixture is heated to 65° C. and reacted under magnetic stirring for 12 h at the temperature, and then filtered, and washed alternately with anhydrous ethanol and deionized water for 5 times, and finally dried in a drying oven at 60° C. for 2 h to obtain functionalized graphene oxide; The preparation method of modified nano zinc oxide is as follows: 5 g of nano zinc oxide is poured into 40 mL of anhydrous ethanol, magnetically stirred for 15 minutes, and then ultrasonically dispersed for 30 minutes; 3 g of sorbic acid is added, the temperature is raised to 60° C., and stirred for reaction for 30 minutes; after the reaction is completed, the anhydrous ethanol is used for centrifugal washing 4 times, and then the precipitate is placed in a vacuum drying oven at 60° C. and dried for 13 hours to obtain modified nano zinc oxide; Step 2: Mix all the components evenly, install a corona impactor on the inner cooling exhaust column of the extrusion blow molding machine, and after the raw materials are melted and plasticized, they enter the die blow molding extrusion cylinder. While blow molding and extrusion, turn on the corona impactor to perform 15,000 volt electric shock treatment on the inner film. After cooling, shaping, pulling, winding and bag making processes, polyethylene clean film and packaging bags are obtained.

[0021] Comparative Example 1 Compared with Example 1, the difference is that the antibacterial agent in Example 1 is not added; the rest remains unchanged.

[0022] Comparative Example 2 Compared with Example 1, the difference is that the functionalized graphene oxide in Example 1 is replaced by graphene oxide; the rest remains unchanged.

[0023] Comparative Example 3 Compared with Example 1, the difference is that the modified nano zinc oxide in Example 1 is replaced by nano zinc oxide; the rest remains unchanged.

[0024] Mechanical properties test: The test was carried out according to the standard of GB / T1040.1-2006; the results are shown in Table 1.

[0025] Antimicrobial performance test: The foodborne pathogen Staphylococcus aureus (S. aureus, Gram-positive bacteria) was used as the test strain and the test was carried out according to the standard of GB / T21510-2008; the results are shown in Table 1.

[0026] Oxygen barrier test: The test was conducted according to GB / T1000.4-2008 standard; the results are shown in Table 1; the calculation formula of oxygen permeability coefficient is: ; Where OP is the oxygen permeability coefficient, cm 3 m / (m 2 ·d·Pa); OTR is oxygen transmission rate, cm 3 / (cm 2 ·d); is the film thickness, m; is the oxygen pressure difference on both sides of the membrane, Pa.

[0027] Water vapor barrier test: The test was conducted according to the standard of GB / T26253-2010, with a relative humidity of 50% and a test temperature of 25°C. The moisture permeability test was conducted after preheating for 1 hour. The water vapor permeability was directly output by the instrument, and the water vapor permeability coefficient was calculated (the results are shown in Table 1): ; Where WVP is the water vapor transmission coefficient, g·m / (m 2 ·s·Pa); is the water vapor transmission rate, g / (m 2 ·d); is the film thickness, m; is the oxygen pressure difference on both sides of the membrane, Pa; is the saturated vapor pressure of water at the measured temperature, Pa; is the relative humidity of the upper part of the test chamber, %; is the relative humidity in the lower part of the test chamber, %.

[0028] Table 1 Tensile strength / MPa Elongation at break / % WVP[×10-7g·m / (m2·s·Pa)] OP[×10-9cm3·m / (m2·d·Pa)] Example 1 23.58 574.18 1.38 0.91 Example 2 22.07 569.82 1.42 0.98 Example 3 20.46 565.27 1.47 1.05 Comparative Example 1 16.15 542.97 5.26 5.14 Comparative Example 2 13.22 531.05 8.19 9.87 Comparative Example 3 12.75 524.46 10.07 10.08 Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0029] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0030] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A polyethylene clean film and packaging bag, characterized in that: The invention comprises the following components in parts by weight: 75-90 parts of low-density polyethylene, 4.5-6 parts of antibacterial agent, 2.5-3.6 parts of functionalized graphene oxide, and 2-3.2 parts of modified nano zinc oxide; The preparation method of the modified nano zinc oxide is: S1. Pour 3-5 g of nano zinc oxide into 25-40 mL of anhydrous ethanol, stir magnetically for 10-15 min, and then perform ultrasonic dispersion treatment for 20-30 min; S2, add 1.5-3g of sorbic acid, raise the temperature to 45-60°C, and stir to react for 20-30min; S3. After the reaction is completed, the precipitate is washed by centrifugation with anhydrous ethanol for 3-4 times, and then placed in a vacuum drying oven at 50-60° C. and dried for 11-13 hours to obtain modified nano zinc oxide.

2. A polyethylene clean film and packaging bag according to claim 1, characterized in that: The preparation method of the antibacterial agent is: 1) Pour 3.5-5g of chitosan into 10-15mL of 10% hydrochloric acid solution and stir until completely dissolved; 2) Add anhydrous ethanol to precipitate, filter the precipitate under reduced pressure, wash it with ethanol 2-4 times, and then dry it in a vacuum drying oven at 55-70°C for 6-8 hours; 3) Pour in 25-40 mL of distilled water, stir until completely dissolved, then add 2-3.6 g of dicyandiamide, and heat to 110-120 ° C under stirring, and react for 2-2.5 hours; 4) After the reaction is completed, cool to room temperature, filter under reduced pressure, wash with anhydrous ethanol for precipitation, and then purify the precipitate by acetone Soxhlet extraction for 22-24 hours. Finally, dry in a vacuum drying oven at 60-70°C for 4-5 hours and grind to obtain the antibacterial agent.

3. A polyethylene clean film and packaging bag according to claim 1, characterized in that: The preparation method of the functionalized graphene oxide is: Pour 0.4-1.5 g of modified graphene oxide into 60-70 mL of anhydrous ethanol, ultrasonically treat for 50-65 min, add 4-6.5 g of hydrazine hydrate, heat to 55-65 ° C, and react under magnetic stirring for 10-12 h at this temperature, then filter, wash alternately with anhydrous ethanol and deionized water 3-5 times, and finally place in a drying oven at 50-60 ° C to dry for 1.5-2 h to obtain functionalized graphene oxide.

4. A polyethylene clean film and packaging bag according to claim 3, characterized in that: The preparation method of the modified graphene oxide is: (1) 0.4-1 g of graphene oxide and 50-60 mL of anhydrous ethanol were mixed, and after ultrasonic treatment for 35-50 min, 10% ammonia water was added dropwise, and the pH value of the solution was adjusted to 2.6-3.2 to prepare solution A; (2) Mix 1.2-2.5 g of KH560 with 50-60 mL of 95% ethanol and perform ultrasonic treatment for 45-60 min to prepare solution B; (3) Under stirring conditions, slowly add solution B to solution A, raise the temperature to 45-60°C, and react with magnetic stirring for 10-12 hours; (4) Filter, wash alternately with anhydrous ethanol and deionized water for 3-5 times, dry in a drying oven at 55-65°C for 1.5-2h, and finally grind to obtain modified graphene oxide.

5. A polyethylene clean film and packaging bag according to claim 1, characterized in that: In S1, the preparation method of nano zinc oxide is: S11, pour 0.05-0.07 mol of zinc acetate dihydrate and 0.075-0.095 mol of citric acid into deionized water, heat the water bath to 60-70°C, and stir for 50-65 minutes; S12, adding ethylene glycol in an equal molar ratio to citric acid, stirring and reacting for 5-8 minutes; S13, add ammonia water dropwise to adjust the pH value of the solution to 7, and continue heating and stirring for 25-35 minutes; S14, first place it in a drying oven at 85-95°C for 4-6 hours to obtain a precursor gel, and then place it in a tubular furnace at 500-550°C for high temperature sintering for 1.5-2 hours to obtain nano zinc oxide.

6. A method for preparing the polyethylene clean film and packaging bag according to claim 1, characterized in that: The specific preparation steps are: Step 1: weigh each component; Step 2: Mix all the components evenly, install a corona impactor on the inner cooling exhaust column of the extrusion blow molding machine, and after the raw materials are melted and plasticized, they enter the die blow molding extrusion cylinder. While blow molding and extrusion, turn on the corona impactor to perform electric shock treatment on the inner film. After cooling, shaping, pulling, winding and bag making processes, polyethylene clean film and packaging bags are obtained.

7. The method for preparing a polyethylene clean film and packaging bag according to claim 6, characterized in that: The voltage of the electric shock is 10,000-15,000 volts.

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