Cellulose acetate nanometer preservative film and preparation method thereof

Abstract

The application relates to the technical field of new preservative film materials, in particular to a cellulose acetate nanometer preservative film and a preparation method thereof. The preparation method comprises the following steps: 1) adding cellulose acetate into an acetic acid aqueous solution, heating, stirring and dissolving to obtain a cellulose acetate solution; 2) adding a modified quaternary ammonium salt chitosan antibacterial agent into the cellulose acetate solution, stirring and uniformly mixing to obtain a spinning solution; 3) sucking the spinning solution into a syringe on a high-pressure electrostatic spinning equipment, then installing a spinning needle on the syringe which has sucked the spinning solution, starting the high-pressure electrostatic spinning equipment to electrostatically spin and form a film, and obtaining the cellulose acetate nanometer preservative film. The cellulose acetate nanometer preservative film prepared by the application not only has good antibacterial performance, but also has good mechanical strength.

Description

Technical Field

[0001] This invention relates to the field of food preservation film technology, and in particular to a cellulose acetate nano-food preservation film and its preparation method. Background Technology

[0002] Currently, most food preservation films on the market are plastic products made from ethylene through polymerization. On the one hand, plastic products harm the environment, a phenomenon commonly known as "white pollution." White pollution negatively impacts water, soil, and the atmosphere, harming the health of living organisms and causing various diseases. Cellulose acetate, also known as cellulose acetate resin, is a thermoplastic resin obtained by esterifying the hydroxyl groups of cellulose under the action of a catalyst. Cellulose acetate is a white solid with characteristics such as stability, ease of processing, non-flammability, low price, abundant raw materials, and biodegradability. It can replace traditional ethylene-based raw materials in the production of food preservation films, eliminating plastic waste and making it environmentally friendly. Cellulose acetate films prepared by electrospinning have advantages such as uniform fineness, small fiber diameter, and low porosity. The preparation of nanofiber materials using cellulose acetate via electrospinning technology is a high-tech process that integrates multidisciplinary research, fundamental theoretical research, and novel product development. With its novel microstructure, unique physical and chemical properties unlike traditional bulk materials, and significant value in both basic research and application, it has become a cutting-edge field in nanomaterials science.

[0003] Antibacterial properties are an important performance indicator for food preservation films. Chitosan quaternary ammonium salts, derivatives of chitosan, exhibit excellent antibacterial properties across a wide pH range. They are also non-toxic, odorless, and readily soluble in water, making their application in the food industry safer and more convenient. Therefore, chitosan quaternary ammonium salts are an ideal antibacterial component for cellulose acetate food preservation films. However, chitosan quaternary ammonium salts are cationic polymers. When dissolved in water, they release positively charged ions. These ions increase the conductivity of the solution. Increased conductivity in the spinning solution can cause beading, resulting in smaller fiber diameters and shorter lengths, which reduces the mechanical strength of the cellulose acetate food preservation film. Summary of the Invention

[0004] To overcome the aforementioned problems in the prior art, this invention provides a cellulose acetate nano-preservative film and its preparation method. The cellulose acetate nano-preservative film prepared by this invention not only possesses excellent antibacterial properties but also good mechanical strength. To achieve the above-mentioned objectives, this invention adopts the following technical solution:

[0005] A method for preparing a cellulose acetate nano-preservative film includes the following steps:

[0006] 1) Add cellulose acetate to an aqueous solution of acetic acid, heat and stir to dissolve, and obtain a cellulose acetate solution;

[0007] 2) Add modified quaternary ammonium salt chitosan antibacterial agent to the cellulose acetate solution, stir and mix evenly to obtain the spinning solution;

[0008] 3) The spinning solution is drawn into the syringe of the high-voltage electrospinning equipment, and then the spinning needle is installed on the syringe containing the spinning solution. The high-voltage electrospinning equipment is then turned on to electrospin and form a film, resulting in cellulose acetate nano-preservative film. Cellulose acetate, also known as cellulose acetate resin, is a thermoplastic resin obtained by esterifying the hydroxyl groups of cellulose under the action of a catalyst. Cellulose acetate is a white solid with characteristics such as stability, ease of processing, non-flammability, low price, abundant raw materials, and biodegradability. This invention uses cellulose acetate instead of the traditional ethylene raw material to prepare preservative film, thus avoiding the generation of plastic waste and making it environmentally friendly. Chitosan quaternary ammonium salt is used as the antibacterial component of the preservative film. Chitosan quaternary ammonium salt is a derivative of chitosan and has good antibacterial properties over a wide pH range. It is also non-toxic, odorless, and easily soluble in water, making its application in the food industry safer and more convenient.

[0009] Preferably, in step 1), the mass concentration of the cellulose acetate solution is 15-20 wt.%.

[0010] Preferably, in step 2), the amount of modified quaternary ammonium salt chitosan antibacterial agent added is 2-5 wt.% of the cellulose acetate solution.

[0011] Preferably, in step 3), the electrospinning conditions are as follows:

[0012] The voltage is 12-15 kV; the spinning solution flow rate is 0.3-0.8 ml / h; and the receiving distance is 7-10 cm.

[0013] Preferably, the preparation method of the modified quaternary ammonium salt chitosan antibacterial agent includes the following steps:

[0014] 21) Add hydrotalcite to anhydrous ethanol, heat and stir until homogeneous to obtain a hydrotalcite suspension;

[0015] 22) Add N,N,N-trimethyl chitosan quaternary ammonium salt to deionized water, heat and stir to dissolve, and obtain N,N,N-trimethyl chitosan quaternary ammonium salt solution;

[0016] 23) Pour the N,N,N-trimethyl chitosan quaternary ammonium salt solution into the hydrotalcite suspension, add dilute nitric acid to adjust the pH to 4-5, heat and stir to react, cool and let stand for more than 12 hours, and then filter, wash and dry to obtain the modified quaternary ammonium salt chitosan antibacterial agent.

[0017] Chitosan quaternary ammonium salt is a derivative of chitosan. Compared to chitosan, it exhibits good antibacterial properties across a wide pH range, and is non-toxic, odorless, and readily soluble in water, making its application in the food industry safer and more convenient. In this invention, chitosan quaternary ammonium salt is added to the cellulose acetate spinning solution to impart antibacterial properties to the electrospun preservation film. However, chitosan quaternary ammonium salt is a cationic polymer. When dissolved in water, the quaternary ammonium salt groups ionize, generating freely migrating cations. These cations can increase the conductivity of the solution. Increased conductivity of the spinning solution can cause beading during spinning, resulting in smaller fiber diameters and shorter lengths, thus reducing the mechanical strength of the cellulose acetate preservation film. To address the aforementioned technical problems, this invention modifies chitosan quaternary ammonium salt. Hydrotalcite is an anionic layered material containing positively charged interlayer surfaces and negatively charged interlayer anions and water molecules. Chitosan quaternary ammonium salt, as a cationic polymer, can be orderly inserted into the interlayer of hydrotalcite through electrostatic interactions, hydrogen bonds, van der Waals forces, etc., forming an organic-inorganic intercalation composite material. This allows the chitosan quaternary ammonium salt to be loaded within the hydrotalcite interlayers, preventing it from dissolving in water and ionizing to release freely migrating cations, thus reducing the conductivity of the spinning solution and avoiding beading during spinning, thereby improving the mechanical strength of the cling film. Furthermore, hydrotalcite exhibits good dispersibility in the spinning solution, ensuring uniform dispersion of the chitosan quaternary ammonium salt during spinning, which helps improve the antibacterial properties of the cling film. Preferably, in step 21), the hydrotalcite undergoes pretreatment.

[0018] γ-(2,3-epoxypropoxy)propyltrimethoxysilane was added to a mixed solution of ethanol and water, and then hydrotalcite was added. The mixture was heated and stirred to obtain coupling agent modified hydrotalcite.

[0019] Sodium alginate was added to deionized water and stirred to dissolve, resulting in a sodium alginate solution. Coupling agent-modified hydrotalcite was added to the sodium alginate solution, and then potassium hydroxide was added to dissolve and adjust the pH to 9-10. The mixture was heated and stirred to react, and after filtration, washing and drying, the final product was obtained.

[0020] Preferably, sodium dodecyl sulfonate is added to the N,N,N-trimethyl chitosan quaternary ammonium salt solution in step 22). In the technical solution of this invention, as described above, the chitosan quaternary ammonium salt is loaded between the hydrotalcite layers to prevent the chitosan quaternary ammonium salt from dissolving in water and ionizing to release freely migrating cations, thus reducing the conductivity of the spinning solution and preventing beading during spinning, thereby improving the mechanical strength of the fiber membrane. However, the problem encountered by the team in loading the chitosan quaternary ammonium salt between the hydrotalcite layers is that the layered hydrotalcite surface carries a positive charge, which forms an electrostatic repulsion force with the positive charge on the chitosan quaternary ammonium salt molecules. Furthermore, the small interlayer spacing of the hydrotalcite layers hinders the intercalation of the chitosan quaternary ammonium salt into the hydrotalcite. Using conventional methods, only a small number of chitosan quaternary ammonium salt molecules intercalate into the hydrotalcite layers, resulting in a decrease in the antibacterial properties of the plastic wrap. Therefore, the team further modified the hydrotalcite: on the one hand, by grafting sodium alginate onto the surface of the hydrotalcite layer, the negative charge of sodium alginate alters the surface charge of the hydrotalcite, preventing the positive charge on the hydrotalcite surface from causing electrostatic repulsion to the chitosan quaternary ammonium salt. On the other hand, by adding sodium dodecyl sulfate to the chitosan quaternary ammonium salt solution, the relatively small molecular weight of sodium dodecyl sulfate allows it to first intercalate into the hydrotalcite layers, thereby increasing the interlayer spacing. This increased interlayer spacing facilitates further intercalation of the chitosan quaternary ammonium salt into the hydrotalcite. Through these two modifications, the present invention enables a sufficient amount of chitosan quaternary ammonium salt to intercalate into the hydrotalcite layers, thereby maintaining the antibacterial properties of the plastic wrap while simultaneously improving its mechanical strength.

[0021] A cellulose acetate nano-preservative film is prepared by the method described above.

[0022] The present invention has the following beneficial effects:

[0023] 1) Using cellulose acetate instead of ethylene as a raw material for making plastic wrap will not generate plastic waste and is green and environmentally friendly;

[0024] 2) Chitosan quaternary ammonium salt is used as the antibacterial component of the food preservation film. Chitosan quaternary ammonium salt is a derivative of chitosan. It has good antibacterial properties in a wide pH range, and is non-toxic, tasteless and easily soluble in water, making its application in the food industry safer and more convenient.

[0025] 3) Loading chitosan quaternary ammonium salt between the hydrotalcite layers prevents the chitosan quaternary ammonium salt from dissolving in water and ionizing into freely migrating cations, thereby reducing the conductivity of the spinning solution and preventing beading during the spinning process, thus improving the mechanical strength of the plastic wrap. Detailed Implementation

[0026] The present invention will be further described clearly and in detail below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0027] Unless otherwise specified, all raw materials used in the embodiments of the present invention are commercially available or obtainable by those skilled in the art; unless otherwise specified, all methods used in the embodiments of the present invention are methods mastered by those skilled in the art.

[0028] Example 1

[0029] The preparation method of cellulose acetate nano-preservative film includes the following steps:

[0030] 1) Add cellulose acetate to a 75% aqueous solution of glacial acetic acid, heat to 50°C, stir to dissolve, and prepare a cellulose acetate solution with a mass concentration of 18 wt.%.

[0031] 2) Add modified quaternary ammonium salt chitosan antibacterial agent to the cellulose acetate solution. The amount of modified quaternary ammonium salt chitosan antibacterial agent added is 4 wt.% of the cellulose acetate solution. Stir and mix evenly to obtain the spinning solution.

[0032] 3) The spinning solution is drawn into the syringe of the high-voltage electrospinning equipment, and then the spinning needle is installed on the syringe that has drawn in the spinning solution. The high-voltage electrospinning equipment is turned on to perform electrospinning and film formation. During the spinning process, the voltage is controlled at 14kV, the flow rate of the spinning solution is 0.6ml / h, and the receiving distance is 9cm to obtain cellulose acetate nano-preservative film.

[0033] The preparation method of modified quaternary ammonium salt chitosan antibacterial agent includes the following steps: 21) Add 2g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to a mixed solution of 80mL ethanol and 10mL water, then add 5g of hydrotalcite, heat to 50℃, stir and react for 50min to obtain coupling agent modified hydrotalcite.

[0034] Add 2g of sodium alginate to 100mL of deionized water and stir to dissolve to obtain sodium alginate solution. Add 5g of coupling agent modified hydrotalcite to sodium alginate solution, then add potassium hydroxide to dissolve and adjust the pH to 10. Heat to 60℃ and stir to react for 2h. After filtration, washing and drying, pretreated hydrotalcite is obtained.

[0035] Add 5g of pretreated hydrotalcite to 150mL of anhydrous ethanol, heat to 45℃, and stir until homogeneous to obtain a hydrotalcite suspension; 22) Add 2g of N,N,N-trimethyl chitosan quaternary ammonium salt and 0.5g of sodium dodecyl sulfonate to 100mL of deionized water, heat to 45℃, and stir until dissolved to obtain an N,N,N-trimethyl chitosan quaternary ammonium salt solution.

[0036] 23) Pour the N,N,N-trimethyl chitosan quaternary ammonium salt solution into the hydrotalcite suspension, add dilute nitric acid to adjust the pH to 5, heat to 60℃, stir and react for 1 hour, cool and let stand for 12 hours, then filter, wash and dry to obtain the modified quaternary ammonium salt chitosan antibacterial agent.

[0037] Example 2

[0038] The preparation method of cellulose acetate nano-preservative film includes the following steps:

[0039] 1) Add cellulose acetate to a 75% aqueous solution of glacial acetic acid, heat to 50°C, stir to dissolve, and prepare a cellulose acetate solution with a mass concentration of 16 wt.%.

[0040] 2) Add modified quaternary ammonium salt chitosan antibacterial agent to the cellulose acetate solution. The amount of modified quaternary ammonium salt chitosan antibacterial agent added is 3 wt.% of the cellulose acetate solution. Stir and mix evenly to obtain the spinning solution.

[0041] 3) The spinning solution is drawn into the syringe of the high-voltage electrospinning equipment, and then the spinning needle is installed on the syringe that has drawn in the spinning solution. The high-voltage electrospinning equipment is turned on to perform electrospinning and film formation. During the spinning process, the voltage is controlled at 13kV, the flow rate of the spinning solution is 0.4ml / h, and the receiving distance is 8cm to obtain cellulose acetate nano-preservative film.

[0042] The preparation method of modified quaternary ammonium salt chitosan antibacterial agent includes the following steps: 21) Add 2g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to a mixed solution of 80mL ethanol and 10mL water, then add 5g of hydrotalcite, heat to 50℃, stir and react for 50min to obtain coupling agent modified hydrotalcite.

[0043] Add 2g of sodium alginate to 100mL of deionized water and stir to dissolve to obtain sodium alginate solution. Add 5g of coupling agent modified hydrotalcite to sodium alginate solution, then add potassium hydroxide to dissolve and adjust pH to 9. Heat to 60℃ and stir to react for 2h. After filtration, washing and drying, pretreated hydrotalcite is obtained.

[0044] Add 5g of pretreated hydrotalcite to 150mL of anhydrous ethanol, heat to 45℃, and stir until homogeneous to obtain a hydrotalcite suspension; 22) Add 2g of N,N,N-trimethyl chitosan quaternary ammonium salt and 0.5g of sodium dodecyl sulfonate to 100mL of deionized water, heat to 45℃, and stir until dissolved to obtain an N,N,N-trimethyl chitosan quaternary ammonium salt solution.

[0045] 23) Pour the N,N,N-trimethyl chitosan quaternary ammonium salt solution into the hydrotalcite suspension, add dilute nitric acid to adjust the pH to 4, heat to 60℃, stir and react for 1 hour, cool and let stand for 12 hours, then filter, wash and dry to obtain the modified quaternary ammonium salt chitosan antibacterial agent.

[0046] Example 3

[0047] The preparation method of cellulose acetate nano-preservative film includes the following steps:

[0048] 1) Add cellulose acetate to a 75% aqueous solution of glacial acetic acid, heat to 50°C, stir to dissolve, and prepare a cellulose acetate solution with a mass concentration of 17 wt.%.

[0049] 2) Add modified quaternary ammonium salt chitosan antibacterial agent to the cellulose acetate solution. The amount of modified quaternary ammonium salt chitosan antibacterial agent added is 3.5 wt.% of the cellulose acetate solution. Stir and mix evenly to obtain the spinning solution.

[0050] 3) The spinning solution is drawn into the syringe of the high-voltage electrospinning equipment, and then the spinning needle is installed on the syringe that has drawn in the spinning solution. The high-voltage electrospinning equipment is turned on to perform electrospinning and film formation. During the spinning process, the voltage is controlled at 13kV, the flow rate of the spinning solution is 0.5ml / h, and the receiving distance is 8cm to obtain cellulose acetate nano-preservative film.

[0051] The preparation method of modified quaternary ammonium salt chitosan antibacterial agent includes the following steps: 21) Add 2g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to a mixed solution of 80mL ethanol and 10mL water, then add 5g of hydrotalcite, heat to 50℃, stir and react for 50min to obtain coupling agent modified hydrotalcite.

[0052] Add 2g of sodium alginate to 100mL of deionized water and stir to dissolve to obtain sodium alginate solution. Add 5g of coupling agent modified hydrotalcite to sodium alginate solution, then add potassium hydroxide to dissolve and adjust pH to 9. Heat to 60℃ and stir to react for 2h. After filtration, washing and drying, pretreated hydrotalcite is obtained.

[0053] Add 5g of pretreated hydrotalcite to 150mL of anhydrous ethanol, heat to 45℃, and stir until homogeneous to obtain a hydrotalcite suspension; 22) Add 2g of N,N,N-trimethyl chitosan quaternary ammonium salt and 0.5g of sodium dodecyl sulfonate to 100mL of deionized water, heat to 45℃, and stir until dissolved to obtain an N,N,N-trimethyl chitosan quaternary ammonium salt solution.

[0054] 23) Pour the N,N,N-trimethyl chitosan quaternary ammonium salt solution into the hydrotalcite suspension, add dilute nitric acid to adjust the pH to 5, heat to 60℃, stir and react for 1 hour, cool and let stand for 12 hours, then filter, wash and dry to obtain the modified quaternary ammonium salt chitosan antibacterial agent.

[0055] Example 4

[0056] The preparation method of cellulose acetate nano-preservative film includes the following steps:

[0057] 1) Add cellulose acetate to a 75% aqueous solution of glacial acetic acid, heat to 50°C, stir to dissolve, and prepare a cellulose acetate solution with a mass concentration of 20 wt.%.

[0058] 2) Add modified quaternary ammonium salt chitosan antibacterial agent to the cellulose acetate solution. The amount of modified quaternary ammonium salt chitosan antibacterial agent added is 5 wt.% of the cellulose acetate solution. Stir and mix evenly to obtain the spinning solution.

[0059] 3) The spinning solution is drawn into the syringe of the high-voltage electrospinning equipment, and then the spinning needle is installed on the syringe that has drawn in the spinning solution. The high-voltage electrospinning equipment is turned on to perform electrospinning and film formation. During the spinning process, the voltage is controlled at 15kV, the flow rate of the spinning solution is 0.8ml / h, and the receiving distance is 10cm to obtain cellulose acetate nano-preservative film.

[0060] The preparation method of modified quaternary ammonium salt chitosan antibacterial agent includes the following steps: 21) Add 2g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to a mixed solution of 80mL ethanol and 10mL water, then add 5g of hydrotalcite, heat to 50℃, stir and react for 50min to obtain coupling agent modified hydrotalcite.

[0061] Add 2g of sodium alginate to 100mL of deionized water and stir to dissolve to obtain sodium alginate solution. Add 5g of coupling agent modified hydrotalcite to sodium alginate solution, then add potassium hydroxide to dissolve and adjust the pH to 10. Heat to 60℃ and stir to react for 2h. After filtration, washing and drying, pretreated hydrotalcite is obtained.

[0062] Add 5g of pretreated hydrotalcite to 150mL of anhydrous ethanol, heat to 45℃, and stir until homogeneous to obtain a hydrotalcite suspension; 22) Add 2g of N,N,N-trimethyl chitosan quaternary ammonium salt and 0.5g of sodium dodecyl sulfonate to 100mL of deionized water, heat to 45℃, and stir until dissolved to obtain an N,N,N-trimethyl chitosan quaternary ammonium salt solution.

[0063] 23) Pour the N,N,N-trimethyl chitosan quaternary ammonium salt solution into the hydrotalcite suspension, add dilute nitric acid to adjust the pH to 5, heat to 60℃, stir and react for 1 hour, cool and let stand for 12 hours, then filter, wash and dry to obtain the modified quaternary ammonium salt chitosan antibacterial agent.

[0064] Example 5

[0065] The preparation method of cellulose acetate nano-preservative film includes the following steps:

[0066] 1) Add cellulose acetate to a 75% aqueous solution of glacial acetic acid, heat to 50°C, stir to dissolve, and prepare a cellulose acetate solution with a mass concentration of 15 wt.%.

[0067] 2) Add modified quaternary ammonium salt chitosan antibacterial agent to the cellulose acetate solution. The amount of modified quaternary ammonium salt chitosan antibacterial agent added is 2 wt.% of the cellulose acetate solution. Stir and mix evenly to obtain the spinning solution.

[0068] 3) The spinning solution is drawn into the syringe of the high-voltage electrospinning equipment, and then the spinning needle is installed on the syringe that has drawn in the spinning solution. The high-voltage electrospinning equipment is turned on to perform electrospinning and film formation. During the spinning process, the voltage is controlled at 12kV, the flow rate of the spinning solution is 0.3ml / h, and the receiving distance is 7cm to obtain cellulose acetate nano-preservative film.

[0069] The preparation method of modified quaternary ammonium salt chitosan antibacterial agent includes the following steps: 21) Add 2g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to a mixed solution of 80mL ethanol and 10mL water, then add 5g of hydrotalcite, heat to 50℃, stir and react for 50min to obtain coupling agent modified hydrotalcite.

[0070] Add 2g of sodium alginate to 100mL of deionized water and stir to dissolve to obtain sodium alginate solution. Add 5g of coupling agent modified hydrotalcite to sodium alginate solution, then add potassium hydroxide to dissolve and adjust pH to 9. Heat to 60℃ and stir to react for 2h. After filtration, washing and drying, pretreated hydrotalcite is obtained.

[0071] Add 5g of pretreated hydrotalcite to 150mL of anhydrous ethanol, heat to 45℃, and stir until homogeneous to obtain a hydrotalcite suspension; 22) Add 2g of N,N,N-trimethyl chitosan quaternary ammonium salt and 0.5g of sodium dodecyl sulfonate to 100mL of deionized water, heat to 45℃, and stir until dissolved to obtain an N,N,N-trimethyl chitosan quaternary ammonium salt solution.

[0072] 23) Pour the N,N,N-trimethyl chitosan quaternary ammonium salt solution into the hydrotalcite suspension, add dilute nitric acid to adjust the pH to 4, heat to 60℃, stir and react for 1 hour, cool and let stand for 12 hours, then filter, wash and dry to obtain the modified quaternary ammonium salt chitosan antibacterial agent.

[0073] Comparative Example 1

[0074] The difference between Comparative Example 1 and Example 1 is as follows:

[0075] No modified quaternary ammonium salt chitosan antibacterial agent is added during the preparation of cellulose acetate nano-preservative film.

[0076] The remaining operating steps are the same as in Example 1.

[0077] Comparative Example 2

[0078] The difference between Comparative Example 2 and Example 1 is as follows:

[0079] In the preparation of cellulose acetate nano-preservative film, the modified quaternary ammonium salt chitosan antibacterial agent is replaced with N,N,N-trimethyl chitosan quaternary ammonium salt.

[0080] The remaining operating steps are the same as in Example 1.

[0081] Comparative Example 3

[0082] The difference between Comparative Example 3 and Example 1 is as follows:

[0083] Sodium alginate is not used to modify hydrotalcite in the preparation of modified quaternary ammonium salt chitosan antibacterial agent.

[0084] The remaining operating steps are the same as in Example 1.

[0085] Comparative Example 4

[0086] The difference between Comparative Example 4 and Example 1 is as follows:

[0087] Sodium dodecyl sulfonate is not added to the N,N,N-trimethyl chitosan quaternary ammonium salt solution during the preparation of the modified quaternary ammonium salt chitosan antibacterial agent.

[0088] The remaining operating steps are the same as in Example 1.

[0089] Performance testing

[0090] 1. Antibacterial performance test:

[0091] The antibacterial properties of the plastic wrap were tested according to the antibacterial performance test method described in GB / T31402 to verify its antibacterial performance and calculate the inhibition rate. The plastic wrap was cut to the test sample size of 50mm × 50mm. The plastic wrap was placed in a sterile petri dish, and 0.4mL of the target bacterial solution was accurately pipetted onto the test sample. The petri dish was then covered, inverted, and placed in a biochemical incubator at 37℃ for 24 hours. Each test group required three independent parallel tests.

[0092]

[0093]

[0094] 2. Mechanical property testing:

[0095] The tensile strength of the plastic wrap was tested using the test method in GB / T 1040.3-2006. The composite film was cut into strips of 150mm × 15mm. Both ends of the test sample were fixed to the fixtures of a universal electronic materials testing machine. The machine's operating parameters were set to 50mm / min. The machine was run until the test sample broke. Each test group required six independent trials, and the values ​​were recorded.

[0096]

[0097] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a cellulose acetate nano-preservative film, characterized in that, Includes the following steps: 1) Add cellulose acetate to an aqueous solution of acetic acid, heat and stir to dissolve, and obtain a cellulose acetate solution; 2) Add modified quaternary ammonium salt chitosan antibacterial agent to the cellulose acetate solution, stir and mix evenly to obtain the spinning solution; 3) The spinning solution is drawn into the syringe of the high-voltage electrospinning equipment, and then the spinning needle is installed on the syringe that has drawn in the spinning solution. The high-voltage electrospinning equipment is turned on to perform electrospinning and film formation to obtain cellulose acetate nano-preservative film. The preparation method of the modified quaternary ammonium salt chitosan antibacterial agent includes the following steps: 21) Add the pretreated hydrotalcite to anhydrous ethanol, heat and stir until homogeneous to obtain a hydrotalcite suspension; wherein, the preparation method of the pretreated hydrotalcite includes the following steps: γ-(2,3-epoxypropoxy)propyltrimethoxysilane was added to a mixed solution of ethanol and water, and then hydrotalcite was added. The mixture was heated and stirred to obtain coupling agent modified hydrotalcite. Sodium alginate was added to deionized water and stirred to dissolve, resulting in a sodium alginate solution. Coupling agent-modified hydrotalcite was added to the sodium alginate solution, and then potassium hydroxide was added to dissolve and adjust the pH to 9-10. The mixture was heated and stirred to react. After filtration, washing and drying, the final product was obtained. 22) Add N,N,N-trimethyl chitosan quaternary ammonium salt and sodium dodecyl sulfonate to deionized water, heat and stir to dissolve, and obtain N,N,N-trimethyl chitosan quaternary ammonium salt solution; 23) Pour the N,N,N-trimethyl chitosan quaternary ammonium salt solution into the hydrotalcite suspension, add dilute nitric acid to adjust the pH to 4-5, heat and stir to react, cool and let stand for more than 12 hours, and then filter, wash and dry to obtain the modified quaternary ammonium salt chitosan antibacterial agent.

2. The method for preparing a cellulose acetate nano-preservative film according to claim 1, characterized in that, In step 1), the mass concentration of the cellulose acetate solution is 15-20 wt.%.

3. The method for preparing a cellulose acetate nano-preservative film according to claim 1, characterized in that, In step 2), the amount of modified quaternary ammonium salt chitosan antibacterial agent added is 2-5 wt.% of the cellulose acetate solution.

4. The method for preparing a cellulose acetate nano-preservative film according to claim 1, characterized in that, In step 3), the electrospinning conditions are as follows: The voltage is 12-15 kV; the spinning solution flow rate is 0.3-0.8 ml / h; and the receiving distance is 7-10 cm.

5. A cellulose acetate nano-preservative film, characterized in that, Prepared by the method described in any one of claims 1-4.

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