Antibacterial agent modified nano silicon dioxide modified polylactic acid film and preparation method thereof

Abstract

The invention relates to the technical field of polylactic acid, and discloses an antibacterial agent modified nano silicon dioxide modified polylactic acid film, nano silicon dioxide reacts with succinyl chloride to obtain acylating chlorinated silicon dioxide, the acylating chlorinated silicon dioxide reacts with polypropylene carbonate to obtain polypropylene carbonate modified silicon dioxide, and the polypropylene carbonate modified silicon dioxide reacts with toluene-2, 4-diisocyanate to obtain the antibacterial agent modified nano silicon dioxide modified polylactic acid film. The preparation method comprises the following steps: carrying out reaction on isocyanated polypropylene carbonate modified silicon dioxide and polylactic acid to obtain isocyanated polypropylene carbonate modified silicon dioxide, further carrying out reaction on the isocyanated polypropylene carbonate modified silicon dioxide and ciprofloxacin, and mixing the isocyanated polypropylene carbonate modified silicon dioxide and polylactic acid to obtain the antibacterial agent modified nano silicon dioxide modified polylactic acid film. The ciprofloxacin group can inhibit the activity of gyrase in bacterial cells, prevent the replication and transcription process of bacterial DNA, further prevent the growth and reproduction of bacterial cells, and finally inactivate bacteria, so that the composite polylactic acid film is endowed with excellent antibacterial performance.

Description

Technical Field

[0001] The invention relates to the technical field of polylactic acid, in particular to an antibacterial agent modified nano-silicon dioxide modified polylactic acid film and a preparation method thereof. Background Art

[0002] In today's ever-developing science and technology, the emergence of plastic packaging materials has greatly facilitated people's lives and has gradually penetrated into all aspects of daily life. Currently, most of the widely used plastic packaging materials are petroleum-based plastics. Long-term use has caused an indelible impact on the environment and has greatly increased the rate of fossil energy consumption. Therefore, it is necessary to use new degradable plastics to replace traditional fossil energy plastics. Polylactic acid, as a biodegradable plastic, has gradually become the mainstream plastic packaging material matrix. However, polylactic acid itself is very brittle, and its mechanical properties and antibacterial properties cannot meet market requirements. Therefore, it is necessary to modify traditional polylactic acid to improve its comprehensive properties such as mechanics, machinery and antibacterial properties.

[0003] Nano-silicon dioxide is an excellent modified material. Its excellent properties such as high strength and hardness make it have good polymer material modification ability. At present, good research results have been achieved. Chinese patents such as CN112521757A and CN101519526A disclose a method of adding nano-silicon dioxide into a polylactic acid matrix to prepare a hybrid composite material with excellent mechanical, heat resistance and other properties. However, most of these patents do not modify the nano-silicon dioxide, resulting in a relatively single functionality of the nano-silicon dioxide. The improvement of the mechanical properties alone cannot improve the comprehensive properties of the polylactic acid matrix such as antibacterial properties. Therefore, it is necessary to modify the nano-silicon dioxide. The hydroxyl groups on the surface of the nano-silicon dioxide can be further grafted with macromolecules with obvious toughening effects such as polypropylene carbonate, or antibacterial functional small molecules such as ciprofloxacin, which can effectively enrich the functionality of the nano-silicon dioxide and improve the dispersibility of the nano-silicon dioxide to a certain extent.

[0004] 1. Technical issues to be resolved

[0005] In view of the shortcomings of the prior art, the present invention provides an antibacterial agent modified nano-silicon dioxide modified polylactic acid film and a preparation method, which solves the problem of poor toughness and antibacterial performance of the polylactic acid film.

[0006] (II) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solution: an antibacterial agent modified nano-silicon dioxide modified polylactic acid film, the preparation method of the antibacterial agent modified nano-silicon dioxide modified polylactic acid film comprises the following steps:

[0008] (1) adding toluene solvent, nano-silica and succinyl chloride to a reactor, mixing them evenly, reacting them at 80-100° C. for 4-10 hours, centrifuging, washing and drying after the reaction to obtain chlorinated silica;

[0009] (2) adding dichloromethane solvent and acyl chloride silica to a reactor, ultrasonically dispersing for 20-40 min, adding polypropylene carbonate and an accelerator, mixing evenly and transferring to an oil bath, reacting at 20-40° C. for 12-36 h, and filtering after the reaction, washing and drying to obtain polypropylene carbonate modified silica;

[0010] (3) adding tetrahydrofuran solvent and polypropylene carbonate modified silica to a reactor, and after uniform ultrasonic dispersion, adding toluene-2,4-diisocyanate, and after uniform mixing, stirring and reacting at 55-75° C. for 2-8 hours. After the reaction is completed, centrifuging, washing and drying to obtain isocyanate polypropylene carbonate modified silica;

[0011] (4) adding tetrahydrofuran solvent and isocyanate-modified polypropylene carbonate silica to a reactor, dispersing by ultrasonication until completely dissolved, then adding ciprofloxacin and dibutyltin dilaurate, mixing evenly, reacting at 60-80° C. for 4-16 h, centrifuging after the reaction, washing and drying to obtain ciprofloxacin-based polypropylene carbonate-modified silica;

[0012] (5) Adding polylactic acid, ciprofloxacin-based polypropylene carbonate modified silica, antioxidant triphenyl phosphite, and plasticizer triethyl citrate into a twin-screw extruder, setting the extrusion temperature to 180-200° C., and using a hot pressing film method to press the masterbatch to obtain an antibacterial agent modified nano-silica modified polylactic acid film.

[0013] Preferably, in the step (1), the mass fraction of toluene solvent is 300-650 parts, the mass fraction of nano-silicon dioxide is 10 parts, and the mass fraction of succinyl chloride is 1.5-5 parts.

[0014] Preferably, in step (2), the mass fraction of dichloromethane solvent is 400-900 parts, the mass fraction of silicon dioxide acyl chloride is 10 parts, the mass fraction of polypropylene carbonate is 25-60 parts, and the mass fraction of accelerator is 3-7 parts.

[0015] Preferably, the promoter in step (2) is triethylamine.

[0016] Preferably, in step (3), the mass fraction of tetrahydrofuran solvent is 200-550 parts, the mass fraction of polypropylene carbonate modified silica is 10 parts, and the mass fraction of toluene-2,4-diisocyanate is 2-6.5 parts.

[0017] Preferably, in step (4), the mass fraction of tetrahydrofuran solvent is 350-850 parts, the mass fraction of isocyanate polypropylene carbonate modified silica is 10 parts, the mass fraction of ciprofloxacin is 1-3.5 parts, and the mass fraction of dibutyltin dilaurate is 0.01-0.04 parts.

[0018] Preferably, in step (5), the mass fraction of polylactic acid is 100 parts, the mass fraction of ciprofloxacin-based polypropylene carbonate modified silica is 12-35 parts, the mass fraction of antioxidant triphenyl phosphite is 0.2-2 parts, and the mass fraction of plasticizer triethyl citrate is 1-3 parts.

[0019] (III) Beneficial technical effects

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] The antibacterial agent modified nano-silica modified polylactic acid film has abundant hydroxyl groups on the surface of the nano-silica, which can undergo esterification reaction with the acyl chloride groups in succinyl chloride to obtain acyl chloride silica; under the action of a promoter, triethylamine, the acyl chloride groups of the acyl chloride silica can undergo esterification reaction with the terminal hydroxyl groups in polypropylene carbonate to obtain polypropylene carbonate modified silica; the remaining hydroxyl groups in the structure can further react with toluene-2,4-diisocyanate to obtain isocyanate polypropylene carbonate modified silica; under the action of a catalyst, dibutyltin dilaurate, the isocyanate further reacts with the imino group in ciprofloxacin to obtain ciprofloxacin-based polypropylene carbonate modified silica, thereby grafting polypropylene carbonate macromolecules and ciprofloxacin antibacterial micromolecules on the surface of the nano-silica through chemical bond connection, effectively enriching the functionality of the nano-silica and further expanding the application range of the nano-silica.

[0022] The antimicrobial agent modified nano-silicon dioxide modified polylactic acid film is prepared by mixing polylactic acid with ciprofloxacin-based polypropylene carbonate modified silicon dioxide and various additives, and then performing a hot pressing film method to finally obtain the antimicrobial agent modified nano-silicon dioxide modified polylactic acid film. Nano-silicon dioxide is a high-strength nanoparticle. When the composite polylactic acid film is subjected to external force, it can withstand a large amount of stress transmitted from the polylactic acid matrix, and at the same time, it disperses the stress into the surface grafted polypropylene carbonate molecular chain, thereby enhancing the composite polylactic acid film to a certain extent. The poly(propylene carbonate) as a flexible long chain can greatly increase the flexibility of the polylactic acid matrix, thereby enhancing the ability of the polylactic acid matrix to absorb plastic deformation work, thereby further improving the mechanical properties of the composite polylactic acid film, such as impact strength. In addition, the ciprofloxacin group grafted on the surface of nano-silica can inhibit the gyrase activity in bacterial cells, prevent the replication and transcription of bacterial DNA, and then prevent the growth and reproduction of bacterial cells, and finally inactivate the bacteria, thereby giving the composite polylactic acid film excellent antibacterial properties. DETAILED DESCRIPTION

[0023] To achieve the above object, the present invention provides the following specific implementation methods and examples: an antibacterial agent modified nano-silicon dioxide modified polylactic acid film, the preparation method comprising the following steps:

[0024] (1) adding 300-650 parts by weight of toluene solvent, 10 parts by weight of nano-silicon dioxide and 1.5-5 parts by weight of succinyl chloride to a reactor, mixing them evenly, reacting them at 80-100° C. for 4-10 hours, centrifuging, washing and drying after the reaction to obtain chlorinated silicon dioxide;

[0025] (2) adding 400-900 parts by weight of dichloromethane solvent and 10 parts by weight of acyl chloride silicon dioxide to a reactor, performing ultrasonic dispersion for 20-40 minutes, adding 25-60 parts by weight of polypropylene carbonate and 3-7 parts by weight of triethylamine, mixing evenly, transferring to an oil bath, reacting at 20-40° C. for 12-36 hours, filtering after the reaction, washing and drying to obtain polypropylene carbonate modified silicon dioxide;

[0026] (3) adding 200-550 parts by weight of tetrahydrofuran solvent and 10 parts by weight of polypropylene carbonate modified silica to a reactor, and after ultrasonic dispersion, adding 2-6.5 parts by weight of toluene-2,4-diisocyanate, mixing evenly, stirring and reacting at 55-75° C. for 2-8 hours, centrifuging after the reaction, washing and drying to obtain isocyanate polypropylene carbonate modified silica;

[0027] (4) adding 350-850 parts by weight of tetrahydrofuran solvent and 10 parts by weight of isocyanate polypropylene carbonate modified silica to a reactor, dispersing by ultrasonic until completely dissolved, then adding 1-3.5 parts by weight of ciprofloxacin and 0.01-0.04 parts by weight of dibutyltin dilaurate, mixing evenly, reacting at 60-80° C. for 4-16 hours, centrifuging after the reaction, washing and drying to obtain ciprofloxacin-based polypropylene carbonate modified silica;

[0028] (5) Add 100 parts by weight of polylactic acid, 12-35 parts by weight of ciprofloxacin-based polypropylene carbonate modified silica, 0.2-2 parts by weight of antioxidant triphenyl phosphite, and 1-3 parts by weight of plasticizer triethyl citrate into a twin-screw extruder, set the extrusion temperature to 180-200° C., and use a hot pressing film method to press the masterbatch to obtain an antibacterial agent modified nano-silica modified polylactic acid film.

[0029] Example 1

[0030] (1) adding 35 mL of toluene solvent, 1 g of nano-silica and 0.15 g of succinyl chloride to a reactor, mixing them evenly, reacting them at 80° C. for 4 h, centrifuging, washing and drying after the reaction, and obtaining chlorinated silica;

[0031] (2) adding 35 mL of dichloromethane solvent and 1 g of acyl chloride silica to the reactor, ultrasonically dispersing for 20 min, adding 2.5 g of polypropylene carbonate and 0.3 g of triethylamine, mixing evenly and transferring to an oil bath, reacting at 20 ° C. for 12 h, and filtering after the reaction, washing and drying to obtain polypropylene carbonate modified silica;

[0032] (3) adding 25 mL of tetrahydrofuran solvent and 1 g of polypropylene carbonate modified silica to a reactor, and after uniform ultrasonic dispersion, adding 0.2 g of toluene-2,4-diisocyanate, and mixing uniformly, stirring and reacting at 55° C. for 2 h. After the reaction is completed, centrifuging, washing and drying to obtain isocyanate polypropylene carbonate modified silica;

[0033] (4) adding 40 mL of tetrahydrofuran solvent and 1 g of isocyanate-modified polypropylene carbonate silica to a reactor, dispersing by ultrasonication until completely dissolved, then adding 0.1 g of ciprofloxacin and 0.001 g of dibutyltin dilaurate, mixing evenly, reacting at 60° C. for 4 h, centrifuging after the reaction, washing and drying to obtain ciprofloxacin-based polypropylene carbonate-modified silica;

[0034] (5) Add 50 g of polylactic acid, 6 g of ciprofloxacin-based polypropylene carbonate modified silica, 0.1 g of antioxidant triphenyl phosphite, and 0.5 g of plasticizer triethyl citrate into a twin-screw extruder, set the extrusion temperature to 180 ° C, and use a hot pressing film method to press the masterbatch to obtain an antibacterial agent modified nano-silica modified polylactic acid film.

[0035] Example 2

[0036] (1) adding 45 mL of toluene solvent, 1 g of nano-silica and 0.3 g of succinyl chloride to a reactor, mixing them evenly, reacting them at 85° C. for 6 h, centrifuging, washing and drying after the reaction, and obtaining chlorinated silica;

[0037] (2) adding 45 mL of dichloromethane solvent and 1 g of acyl chloride silica to the reactor, ultrasonically dispersing for 25 min, adding 3.8 g of polypropylene carbonate and 0.4 g of triethylamine, mixing evenly and transferring to an oil bath, reacting at 25 ° C. for 15 h, and filtering after the reaction, washing and drying to obtain polypropylene carbonate modified silica;

[0038] (3) adding 40 mL of tetrahydrofuran solvent and 1 g of polypropylene carbonate modified silica to a reactor, and after uniform ultrasonic dispersion, adding 0.35 g of toluene-2,4-diisocyanate, and mixing uniformly, stirring and reacting at 60° C. for 4 h, and after the reaction is completed, centrifuging, washing and drying to obtain isocyanate polypropylene carbonate modified silica;

[0039] (4) adding 60 mL of tetrahydrofuran solvent and 1 g of isocyanate-modified polypropylene carbonate silica to a reactor, dispersing by ultrasonication until completely dissolved, then adding 0.2 g of ciprofloxacin and 0.002 g of dibutyltin dilaurate, mixing evenly, reacting at 65° C. for 8 h, centrifuging after the reaction, washing and drying to obtain ciprofloxacin-based polypropylene carbonate-modified silica;

[0040] (5) Add 50 g of polylactic acid, 10 g of ciprofloxacin-based polypropylene carbonate modified silica, 0.4 g of antioxidant triphenyl phosphite, and 0.8 g of plasticizer triethyl citrate into a twin-screw extruder, set the extrusion temperature to 185 ° C, and use a hot pressing film method to press the masterbatch to obtain an antibacterial agent modified nano-silica modified polylactic acid film.

[0041] Example 3

[0042] (1) adding 60 mL of toluene solvent, 1 g of nano-silica and 0.4 g of succinyl chloride to a reactor, mixing them evenly, reacting them at 90° C. for 8 h, centrifuging, washing and drying after the reaction, and obtaining chlorinated silica;

[0043] (2) adding 50 mL of dichloromethane solvent and 1 g of acyl chloride silica to the reactor, ultrasonically dispersing for 30 min, adding 5 g of polypropylene carbonate and 0.5 g of triethylamine, mixing evenly and transferring to an oil bath, reacting at 30 ° C. for 24 h, and filtering after the reaction, washing and drying to obtain polypropylene carbonate modified silica;

[0044] (3) adding 50 mL of tetrahydrofuran solvent and 1 g of polypropylene carbonate modified silica to a reactor, and after uniform ultrasonic dispersion, adding 0.5 g of toluene-2,4-diisocyanate, and mixing evenly, stirring and reacting at 65° C. for 6 h. After the reaction is completed, centrifuging, washing and drying to obtain isocyanate polypropylene carbonate modified silica;

[0045] (4) adding 80 mL of tetrahydrofuran solvent and 1 g of isocyanate-modified polypropylene carbonate silica to a reactor, dispersing by ultrasonication until completely dissolved, then adding 0.3 g of ciprofloxacin and 0.003 g of dibutyltin dilaurate, mixing evenly, reacting at 70° C. for 12 h, centrifuging after the reaction, washing and drying to obtain ciprofloxacin-based polypropylene carbonate-modified silica;

[0046] (5) Add 50 g of polylactic acid, 14 g of ciprofloxacin-based polypropylene carbonate modified silica, 0.8 g of antioxidant triphenyl phosphite, and 1.2 g of plasticizer triethyl citrate into a twin-screw extruder, set the extrusion temperature to 190 ° C, and use a hot pressing film method to press the masterbatch to obtain an antibacterial agent modified nano-silica modified polylactic acid film.

[0047] Example 4

[0048] (1) adding 75 mL of toluene solvent, 1 g of nano-silica and 0.5 g of succinyl chloride into a reactor, mixing them evenly, reacting them at 100° C. for 10 h, centrifuging, washing and drying after the reaction to obtain chlorinated silica;

[0049] (2) Add 65 mL of dichloromethane solvent and 1 g of acyl chloride silica to the reactor, perform ultrasonic dispersion for 40 min, add 6 g of polypropylene carbonate and 0.7 g of triethylamine, mix well and transfer to an oil bath, react at 40 ° C for 36 h, filter after the reaction, wash and dry to obtain polypropylene carbonate modified silica;

[0050] (3) adding 60 mL of tetrahydrofuran solvent and 1 g of polypropylene carbonate modified silica to a reactor, and after uniform ultrasonic dispersion, adding 0.65 g of toluene-2,4-diisocyanate, and mixing uniformly, stirring and reacting at 75° C. for 8 h, and after the reaction is completed, centrifuging, washing and drying to obtain isocyanate polypropylene carbonate modified silica;

[0051] (4) adding 95 mL of tetrahydrofuran solvent and 1 g of isocyanate-modified polypropylene carbonate silica to a reactor, dispersing by ultrasonication until completely dissolved, and then adding 0.35 g of ciprofloxacin and 0.004 g of dibutyltin dilaurate, mixing evenly, reacting at 80° C. for 16 h, centrifuging after the reaction, washing and drying to obtain ciprofloxacin-based polypropylene carbonate-modified silica;

[0052] (5) Add 50 g of polylactic acid, 17.5 g of ciprofloxacin-based polypropylene carbonate modified silica, 1 g of antioxidant triphenyl phosphite, and 1.5 g of plasticizer triethyl citrate into a twin-screw extruder, set the extrusion temperature to 200 ° C, and use a hot pressing film method to press the masterbatch to obtain an antibacterial agent modified nano-silica modified polylactic acid film.

[0053] Comparative Example 1

[0054] (1) adding 40 mL of toluene solvent, 1 g of nano-silica and 0.18 g of succinyl chloride to a reactor, mixing them evenly, reacting them at 85° C. for 5 h, centrifuging, washing and drying after the reaction, and obtaining chlorinated silica;

[0055] (2) adding 40 mL of dichloromethane solvent and 1 g of acyl chloride silica to the reactor, ultrasonically dispersing for 25 min, adding 2.8 g of polypropylene carbonate and 0.4 g of triethylamine, mixing evenly and transferring to an oil bath, reacting at 25 ° C. for 13 h, and filtering after the reaction, washing and drying to obtain polypropylene carbonate modified silica;

[0056] (3) Add 50 g of polylactic acid, 7 g of polypropylene carbonate modified silica, 0.2 g of antioxidant triphenyl phosphite, and 0.6 g of plasticizer triethyl citrate into a twin-screw extruder, set the extrusion temperature to 185°C, and use a hot pressing film method to press the masterbatch to obtain a polypropylene carbonate grafted silica modified polylactic acid film.

[0057] Comparative Example 2

[0058] (1) adding 70 mL of toluene solvent, 1 g of nano-silica and 0.48 g of succinyl chloride to a reactor, mixing them evenly, reacting them at 110° C. for 8 h, centrifuging, washing and drying after the reaction, and obtaining chlorinated silica;

[0059] (2) Add 50 g of polylactic acid, 16 g of silicon dioxide chloride, 0.9 g of antioxidant triphenyl phosphite, and 1.4 g of plasticizer triethyl citrate into a twin-screw extruder, set the extrusion temperature to 195° C., and use a hot pressing film method to press the masterbatch to obtain a silica-modified polylactic acid film.

[0060] The composite films in the examples and comparative examples were prepared into samples with a size of 2 mm×2 cm×2 cm, and 100 mL of 5×10 5 cfu / mL Escherichia coli suspension in a culture dish, place the dish in a constant temperature incubator at 37°C, and after culturing for 72 hours, use an ultraviolet spectrophotometer to test the bacterial concentration and calculate the antibacterial rate. The blank control test is performed without adding samples.

[0061]

[0062] The composite films in the examples and comparative examples were prepared into samples with a size of 4 mm×8 cm×8 cm, and the impact strength thereof was tested using a BLD-BC-30B impact testing machine in accordance with the test standard GB / T 1043.1-2008.

[0063]

Claims

1. An antibacterial agent modified nano-silicon dioxide modified polylactic acid film, characterized in that: The following steps are involved: (1) Adding nano-silica and succinyl chloride to a toluene solvent, mixing well, reacting at 80-100° C. for 4-10 hours, centrifuging, washing and drying after the reaction to obtain acyl chloride silica; (2) Add acyl chloride silica to dichloromethane solvent, ultrasonically disperse for 20-40 minutes, add polypropylene carbonate and accelerator, mix well and transfer to an oil bath, react at 20-40°C for 12-36 hours, filter after the reaction, wash and dry to obtain polypropylene carbonate modified silica; (3) adding polypropylene carbonate modified silica to tetrahydrofuran solvent, and after ultrasonic dispersion, adding toluene-2,4-diisocyanate, and mixing evenly, stirring and reacting at 55-75° C. for 2-8 hours. After the reaction is completed, centrifuging, washing and drying to obtain isocyanate polypropylene carbonate modified silica; (4) adding isocyanate-modified polypropylene carbonate silica to tetrahydrofuran solvent, dispersing by ultrasonic until completely dissolved, then adding ciprofloxacin and dibutyltin dilaurate, mixing evenly, reacting at 60-80° C. for 4-16 h, centrifuging after the reaction, washing and drying to obtain ciprofloxacin-based polypropylene carbonate modified silica; (5) Add polylactic acid, ciprofloxacin-based polypropylene carbonate modified silica, antioxidant triphenyl phosphite, and plasticizer triethyl citrate into a twin-screw extruder, set the extrusion temperature to 180-200°C, and use a hot pressing film method to press the masterbatch to obtain an antibacterial agent modified nano-silica modified polylactic acid film.

2. The antibacterial agent modified nano-silicon dioxide modified polylactic acid film according to claim 1, characterized in that: In the step (1), the mass fraction of toluene solvent is 300-650 parts, the mass fraction of nano-silicon dioxide is 10 parts, and the mass fraction of succinyl chloride is 1.5-5 parts.

3. The antibacterial agent modified nano-silicon dioxide modified polylactic acid film according to claim 1, characterized in that: In the step (2), the mass fraction of the dichloromethane solvent is 400-900 parts, the mass fraction of the acyl chloride silicon dioxide is 10 parts, the mass fraction of the polypropylene carbonate is 25-60 parts, and the mass fraction of the accelerator is 3-7 parts.

4. The antibacterial agent modified nano-silicon dioxide modified polylactic acid film according to claim 1, characterized in that: The promoter in step (2) is triethylamine.

5. The antibacterial agent modified nano-silicon dioxide modified polylactic acid film according to claim 1, characterized in that: In the step (3), the mass fraction of tetrahydrofuran solvent is 200-550 parts, the mass fraction of polypropylene carbonate modified silica is 10 parts, and the mass fraction of toluene-2,4-diisocyanate is 2-6.5 parts.

6. The antibacterial agent modified nano-silicon dioxide modified polylactic acid film according to claim 1, characterized in that: In the step (4), the mass fraction of tetrahydrofuran solvent is 350-850 parts, the mass fraction of isocyanate polypropylene carbonate modified silica is 10 parts, the mass fraction of ciprofloxacin is 1-3.5 parts, and the mass fraction of dibutyltin dilaurate is 0.01-0.04 parts.

7. The antibacterial agent modified nano-silicon dioxide modified polylactic acid film according to claim 1, characterized in that: In the step (5), the mass fraction of polylactic acid is 100 parts, the mass fraction of ciprofloxacin-based polypropylene carbonate modified silica is 12-35 parts, the mass fraction of antioxidant triphenyl phosphite is 0.2-2 parts, and the mass fraction of plasticizer triethyl citrate is 1-3 parts.

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