PLA / PBAT / nano composite antibacterial film material and preparation method thereof

Abstract

The invention relates to the field of degradable antibacterial materials, and discloses a PLA / PBAT / nano composite antibacterial film material and a preparation method thereof.The preparation method comprises the steps that a quaternary ammonium salt monomer compound and glycidyl methacrylate are mixed, organic nano montmorillonite is added, and ultrasonic vibration is performed to obtain a mixed solution; dissolving lauryl sodium sulfate in deionized water, then adding the mixed solution and a potassium persulfate aqueous solution for reaction, then demulsifying with a saturated saline solution, washing, carrying out suction filtration, and drying to obtain an organic nano-montmorillonite / quaternary ammonium salt-GMA copolymer; polylactic acid, poly (butylene adipate terephthalate) and the organic nano-montmorillonite / quaternary ammonium salt-GMA copolymer are plasticized, extruded, pelletized and dried through an extruder, and the PLA / PBAT / nano composite antibacterial film material is obtained. The quaternary ammonium salt-GMA copolymer is a chain extension compatilizer with antibacterial functional groups and has two functional groups, the compatibility of PLA / PBAT can be improved through an epoxy group of the copolymer, and the antibacterial performance can be provided for a blend through a quaternary ammonium salt group.

Description

Technical Field

[0001] This invention relates to the field of biodegradable antibacterial materials, specifically to a PLA / PBAT / nanocomposite antibacterial membrane material and its preparation method. Background Technology

[0002] Polylactic acid (PLA) and polybutylene terephthalate (PBAT) are the most commonly used biodegradable materials. PLA is hard and brittle, while PBAT has good toughness but insufficient strength. Due to their respective characteristics, they are often used in blending modification technology to produce biodegradable membrane materials to improve their respective shortcomings. Existing PLA / PBAT membrane materials often use multi-component epoxy chain extenders as compatibilizers due to the compatibility issues between PLA and PBAT phases. This increases the compatibility of the blend and improves the performance of the blended membrane material. Chain extension technology is an effective modification method that can increase the branching degree of PLA and PBAT, significantly improving their relative molecular mass, thereby reducing the loss of relative molecular mass during processing and enhancing melt strength. The chain extension reaction changes the microstructure of PLA / PBAT by introducing other molecular chains or active functional groups. The key is to reduce the regularity of the molecular chains, thereby improving the performance defects of PLA / PBAT. Epoxy chain extenders can undergo chain extension reactions with PLA / PBAT, effectively increasing the end length of PLA / PBAT molecular chains and altering their microstructure. This modification method aims to reduce the regularity of PLA / PBAT molecular chains, thereby significantly improving the performance of PLA / PBAT blends.

[0003] PLA / PBA membrane antibacterial technology often uses inorganic nanomaterials such as silver-loaded antibacterial agents or organic low-molecular-weight antibacterial agents. However, these antibacterial agents have shortcomings such as product discoloration due to the separation and dissolution of antibacterial components, short service life, large toxic side effects, and rapid decay of antibacterial performance. The purpose of this invention is to substantially improve the performance of antibacterial materials from the perspective of the stability of antibacterial components in membrane materials, especially to increase the service life of antibacterial agents and reduce toxic side effects. Summary of the Invention

[0004] To overcome the aforementioned drawbacks, this invention provides a PLA / PBAT / nanocomposite antibacterial membrane material. The antibacterial component is a polymeric material composed of copolymers, with the antibacterial components of the antibacterial monomers forming part of its polymeric structure. Simultaneously, this copolymer also acts as a compatibility chain extender for PLA / PBAT blends, effectively reducing phase separation in the PLA and PBAT blend. The antibacterial component copolymer melted into the blend also prevents the separation and dissolution of the antibacterial components. Therefore, the antibacterial activity or performance of the antibacterial polymer is very stable. The prepared nanocomposite antibacterial material shows significant improvements in the stability, antibacterial activity, and antibacterial performance of the antibacterial component compared to antibacterial materials based on silver loading, small-molecule antibacterial compounds, etc. This solves the problems of poor compatibility, decreased mechanical properties, easy discoloration, high toxicity, and degradation of antibacterial performance after molding and processing that have plagued PLA / PBAT antibacterial membrane materials. It is a novel PLA / PBAT / nanocomposite antibacterial membrane material with significant development potential.

[0005] To achieve the above objectives, the present invention provides a method for preparing a PLA / PBAT / nanocomposite antibacterial membrane material, comprising the following steps:

[0006] S1, Monomer Intercalation

[0007] A copolymerizable quaternary ammonium salt monomer compound with unsaturated double bonds is mixed with glycidyl methacrylate and organic nano-montmorillonite is added. The mixture is mechanically stirred and / or ultrasonically vibrated so that part of the mixture of quaternary ammonium salt monomer compound and glycidyl methacrylate enters the layered nanospace of organic nano-montmorillonite.

[0008] S2, in-situ polymerization

[0009] Sodium dodecyl sulfate was dissolved in deionized water and added to the mixture obtained by monomer intercalation in step S1. After heating to the set temperature, persulfate aqueous solution used as an initiator was added to react and form a complex emulsion. Then, the emulsion was broken with saturated brine, washed, filtered, and dried to obtain an organic nano-montmorillonite / quaternary ammonium salt-GMA copolymer.

[0010] S3, blending modification

[0011] Polylactic acid, polybutylene adipate and organic nano-montmorillonite / quaternary ammonium salt-GMA copolymer were blended by extruder at 145-175℃, plasticized, extruded and granulated and then dried to obtain PLA / PBAT / nano-composite antibacterial film material.

[0012] The composition, by mass parts, is as follows: 5-95 parts polylactic acid, 5-95 parts polybutylene adipate terephthalate, and 0.1-10 parts organic nano-montmorillonite / quaternary ammonium salt-GMA copolymer.

[0013] As a further preferred embodiment of the present invention, the quaternary ammonium salt monomer compound is selected from at least one of vinylbenzyldimethyl-n-octylammonium salt, vinylbenzyldimethyl-n-decylammonium salt, vinylbenzyldimethyl-n-dodecylammonium salt, vinylbenzyldimethyl-n-hexadecylammonium salt, 2-acryloyloxyhexyltrimethylammonium salt, 2-methacryloyloxyethyltrimethylammonium salt, acryloylaminopropyltrimethylammonium salt, aminopropylmethacrylatetrimethylammonium salt, acrylate alkylpyridinium salt, and methacryloyloxyalkylpyridinium salt.

[0014] As a further preferred technical solution of the present invention, by mass parts: 50-70 parts of polylactic acid, 35-50 parts of polybutylene adipate terephthalate, and 0.5-2 parts of organic nano-montmorillonite / quaternary ammonium salt-GMA copolymer.

[0015] As a further preferred technical solution of the present invention, the organic nano-montmorillonite is chemically pure and has an ion exchange capacity (CEC) of 110-120 mmol / 100g.

[0016] As a further preferred embodiment of the present invention, the persulfate is potassium persulfate, ammonium persulfate, or sodium persulfate.

[0017] As a further preferred technical solution of the present invention, in step S1, the mass ratio of glycidyl methacrylate, quaternary ammonium salt monomer compound and organic nano-montmorillonite is 1:1:0.05~0.5; and / or, in step S2, the mass ratio of sodium dodecyl sulfate to the mixture in step S1 is 1:10~100.

[0018] As a further preferred technical solution of the present invention, in step S1: when only mechanical stirring is used, the stirring speed is greater than 800 rpm and the time is greater than 5 min, more preferably the stirring speed is 800~1500 rpm and the time is 5~30 min; when only ultrasonic oscillation is used, the ultrasonic power is greater than 20 kHz and the time is greater than 5 min, more preferably the ultrasonic power is 20~60 kHz and the time is 5~30 min. When mechanical stirring and ultrasonic oscillation are used, the respective action time can be appropriately reduced, but the total time should not be less than 5 min, to ensure that sufficient quaternary ammonium salt monomer compound and glycidyl methacrylate-esterified mixture enter the layered nanospace of the organic nano-montmorillonite.

[0019] In step S1, the mass ratio of glycidyl methacrylate, quaternary ammonium salt monomer compound and organic nano-montmorillonite is 1:1:0.05~0.5; and / or, the mechanical stirring speed is 800~1500 rpm and the time is 5~30 min.

[0020] As a further preferred embodiment of the present invention, the reaction in step S2 is carried out in a three-necked flask equipped with a stirrer, a reflux condenser and a thermometer.

[0021] As a further preferred embodiment of the present invention, the mass percentage concentration of the saturated saline solution is 5-10%.

[0022] According to a second aspect of the present invention, the present invention also provides a PLA / PBAT / nanocomposite antibacterial membrane material, which is prepared by the above-described preparation method.

[0023] According to a third aspect of the present invention, the present invention also provides the use of PLA / PBAT / nanocomposite antibacterial membrane material as an antibacterial membrane.

[0024] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0025] (1) The important component of this invention, the quaternary ammonium salt-GMA copolymer, is a chain extender compatibilizer with antibacterial functional groups. It has two functional groups, of which the epoxy group can improve the compatibility of PLA / PBAT, and the quaternary ammonium salt group can provide the blend with efficient and stable antibacterial properties.

[0026] (2) When the important component of this invention, the quaternary ammonium salt-GMA copolymer, is blended with PLA / PBAT, it plays a chain extension compatibility role and can undergo a chain extension reaction with PLA / PBAT, so that it forms a new macromolecule with the two phases of PLA / PBAT, rather than a simple mixture. The antibacterial group becomes part of the new macromolecule, rather than being mixed in the blend. In this way, there will be no problems such as decreased antibacterial ability, toxicity, and discoloration caused by the precipitation and detachment of antibacterial components in the existing silver-loaded or small molecule antibacterial agents. Detailed Implementation

[0027] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0028] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0029] The organic nano-montmorillonite (OMMT) used in the following examples is chemically pure with an ion exchange capacity (CEC) of 120 mmol / 100 g; the emulsifier is sodium dodecyl sulfate (SDS), analytical grade; and the initiator is potassium persulfate (K2S2O8), analytical grade.

[0030] Example 1

[0031] This embodiment provides a method for preparing a PLA / PBAT / nanocomposite antibacterial material, which is carried out according to the following steps:

[0032] 1) Monomer intercalation

[0033] 0.5g of OMMT was added to a mixture of 5g of vinylbenzyldodecylamine as a copolymerizable antibacterial monomer and 5g of GMA. The mixture was stirred at high speed (1000 rpm) for 10 minutes and then ultrasonically vibrated. The ultrasonic vibrator was set to 40kHz, starting at 50% power and gradually increasing to 70% power for 10 minutes. This combination of high-speed stirring and ultrasonic vibration allowed some of the copolymerizable antibacterial monomer and GMA monomer to enter the layered nanospace of OMMT, resulting in a mixture of OMMT and the polymerizable monomers vinylbenzyldodecylamine and GMA.

[0034] 2) In-situ copolymerization

[0035] Add 90 ml of deionized water and 0.2 g of SDS to a 250 ml three-necked flask equipped with a stirrer, reflux condenser and thermometer, and stir until homogeneous. Then, while mechanically stirring (stirring speed 200 rpm), add all the OMMT treated in step 1) and the polymerizable monomers vinylbenzyldodecylamine and GMA mixture. Heat in a water bath at a rate of 1-2 °C / min. Dissolve 2 g of K2S2O8 in 10 ml of deionized water. When the water bath reaches 70 °C, add the K2S2O8 aqueous solution and react for 2 hours to obtain a polymer emulsion. At this time, some monomers copolymerize in the layered space of OMMT to form a nanocomposite antibacterial material. Cool to room temperature, then demulsify with 13% saturated saline, wash, filter, and finally dry at 70 °C to obtain nano OMMT / quaternary ammonium salt-GMA copolymer.

[0036] 3) Blending modification

[0037] PLA, PBAT dried at 55 ℃ for 24 hours, and nano-OMMT / quaternary ammonium salt-GMA copolymer dried at 70 ℃ for 12 hours were fed into a twin-screw extruder according to the following ratio: PBAT:PLA:nano-OMMT / quaternary ammonium salt-GMA copolymer = 60:40:1. The plasticizing extrusion was carried out at a temperature of 145-175 ℃ in each zone of the twin-screw extruder and a main extruder speed of 180 rpm. After water cooling and pelletizing, the product was dried to obtain PLA / PBAT / nano-antibacterial film material.

[0038] Example 2

[0039] Compared to Example 1, the only difference is the type of quaternary ammonium salt monomer compound. Vinylbenzyl dimethyl n-octylammonium salt is used instead of vinylbenzyl dodecylamine as the copolymerizable antibacterial monomer to prepare PLA / PBAT / nanocomposite antibacterial membrane material.

[0040] Example 3

[0041] Compared to Example 1, the only difference is the type of quaternary ammonium salt monomer compound. Vinylbenzyldimethyl-n-decylammonium salt is used instead of vinylbenzyldodecylamine as the copolymerizable antibacterial monomer to prepare PLA / PBAT / nanocomposite antibacterial membrane material.

[0042] Example 4

[0043] Compared to Example 1, the only difference is the type of quaternary ammonium salt monomer compound. Vinylbenzyl dimethyl n-dodecylammonium salt is used instead of vinylbenzyl dodecylamine to create a copolymerizable antibacterial monomer PLA / PBAT nanocomposite antibacterial membrane material.

[0044] Example 5

[0045] Compared to Example 1, the only difference is the type of quaternary ammonium salt monomer compound. Vinylbenzyl dimethyl n-hexadecylammonium salt is used instead of vinylbenzyl dodecylamine as the copolymerizable antibacterial monomer to prepare PLA / PBAT / nanocomposite antibacterial membrane material.

[0046] Example 6

[0047] Compared to Example 1, the only difference is the type of quaternary ammonium salt monomer compound. 2-Acryloyloxyhexyltrimethylammonium salt is used instead of vinylbenzyldodecylamine as the copolymerizable antibacterial monomer to prepare PLA / PBAT / nanocomposite antibacterial membrane material.

[0048] Example 7

[0049] Compared to Example 1, the only difference is the type of quaternary ammonium salt monomer compound. 2-methacryloyloxyethyltrimethylammonium salt is used instead of vinylbenzyldodecylamine as the copolymerizable antibacterial monomer to prepare PLA / PBAT / nanocomposite antibacterial membrane material.

[0050] Example 8

[0051] Compared to Example 1, the only difference is the type of quaternary ammonium salt monomer compound. Acryloylaminopropyltrimethylammonium salt is used instead of vinylbenzyldodecylamine as the copolymerizable antibacterial monomer to prepare PLA / PBAT / nanocomposite antibacterial membrane material.

[0052] Example 9

[0053] Compared to Example 1, the only difference is the type of quaternary ammonium salt monomer compound. In this example, aminopropyltrimethylammonium methacrylate is used instead of vinylbenzyldodecylamine as the copolymerizable antibacterial monomer to prepare PLA / PBAT / nanocomposite antibacterial membrane material.

[0054] Example 10

[0055] Compared to Example 1, the only difference is the type of quaternary ammonium salt monomer compound. Acrylate alkylpyridinium salt is used instead of vinyl benzyl dodecylamine as the copolymerizable antibacterial monomer to prepare PLA / PBAT / nanocomposite antibacterial membrane material.

[0056] Example 11

[0057] Compared to Example 1, the only difference is the type of quaternary ammonium salt monomer compound. In this example, methacryloyloxyalkylpyridinium salt is used instead of vinylbenzyldodecylamine as the copolymerizable antibacterial monomer to prepare PLA / PBAT / nanocomposite antibacterial membrane material.

[0058] Comparative Example 1

[0059] PLA and PBAT, dried at 55 ℃ for 24 hours, were fed into a twin-screw extruder with a mass ratio of PBAT:PLA of 60:40. After plasticizing, extruding, pelletizing, and drying at a temperature of 145-175 ℃ in each zone of the twin screw and a main extruder speed of 180 rpm, the PLA / PBAT blend was obtained as control sample 1.

[0060] Comparative Example 2

[0061] PLA and PBAT, dried at 55 ℃ for 24 hours, were fed into a twin-screw extruder with a mass ratio of PBAT:PLA:ADR4468 (BASF chain extender) of 60:40:0.5. After plasticizing, extruding, pelletizing, and drying at a temperature of 145-175 ℃ in each zone of the twin-screw and a main extruder speed of 180 rpm, the resulting ADR-compensated PLA / PBAT blend was used as control sample 2.

[0062] Comparative Example 3

[0063] 1) Add 0.5g OMMT to a mixture of 5g vinylbenzyldodecylamine as a copolymerizable antibacterial monomer and 5g GMA to form a mixture; then add 90ml deionized water and 0.2g SDS to a 250ml three-necked flask equipped with a stirrer, reflux condenser and thermometer and stir until homogeneous. Then add the mixture while mechanically stirring (stirring speed 200rpm), heat in a water bath at a rate of 1-2℃ / min, dissolve 2g K2S2O8 in 10ml deionized water, and when the water bath reaches 70℃, add the K2S2O8 aqueous solution. React for 2 hours to obtain a polymer emulsion. At this time, some monomers copolymerize in the layered space of OMMT to form a nanocomposite antibacterial material. Cool to room temperature, then demulsify with 13% saturated saline, wash, filter, and finally dry at 70℃ to obtain nano OMMT / quaternary ammonium salt-GMA copolymer.

[0064] 2) PLA, PBAT dried at 55 ℃ for 24 hours, and nano OMMT / quaternary ammonium salt-GMA copolymer dried at 70 ℃ for 12 hours were added to a twin-screw extruder according to the following ratio: PBAT: PLA: nano OMMT / quaternary ammonium salt-GMA copolymer was 60:40:1. The product was plasticized, extruded, water-cooled, pelletized, and dried after being plasticized at a temperature of 145-175 ℃ in each zone of the twin screw and a main extruder speed of 180 rpm. The resulting product was used as control sample 3.

[0065] The melt mass flow rate (MFR) of the samples from Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 was determined at 190 °C and 2.16 kg according to GB / T 3682, as shown in Table 1.

[0066] Table 1. Melt mass flow rates of Example 1 and Comparative Examples 1-3

[0067]

[0068] As shown in Table 1, the melt flow rate of Example 1 and Comparative Example 2 is significantly lower, the melt viscosity is higher, and the molecular weight is larger. Compared with Comparative Example 1 without chain extender, the chain extension and compatibility are significantly improved. The effect of Example 1 is slightly worse than that of Comparative Example 2 with BASF's special chain extender ADR4468, but the difference is not significant; the chain extension compatibility can be achieved.

[0069] Samples from Example 1 and Comparative Examples 1, 2, and 3 were injection molded into tensile dumbbell test strips using a micro injection molding machine at a material temperature of 190°C and a mold temperature of 40°C. The mechanical properties of Example 1, Comparative Examples 1 and 2 were tested according to GB / T 1040.2, as shown in Table 2.

[0070] Table 2 Comparison of mechanical properties of Example 1 and Comparative Examples 1-3

[0071]

[0072] As shown in Table 2, compared with Comparative Example 1, Example 1 showed a significant increase in tensile strength, tensile strain at break, and tensile modulus. Although slightly inferior to Comparative Example 2, which added BASF's special chain extender compatibilizer ADR4468, the difference was not significant and could meet the requirements for two-phase chain extension compatibility applications. Although Comparative Example 3 had the same components as Example 1, it did not use mechanical stirring and / or ultrasonic oscillation to allow sufficient quaternary ammonium salt monomer compound and glycidyl methacrylate esterified mixture to enter the layered nanospace of the organic nano-montmorillonite. The resulting copolymer did not adequately improve the PLA / PBAT compatibility and could not effectively improve the performance of the PLA / PBAT blend. Its mechanical properties were basically equivalent to those of the pure PLA / PBAT blend.

[0073] Antibacterial test: Staphylococcus aureus and Escherichia coli were used as indicator bacteria for Gram-positive cocci and Gram-negative bacilli, respectively, and Candida albicans was used as an indicator fungus. Antibacterial performance was determined based on the inhibition rate. Staphylococcus aureus and Escherichia coli were inoculated into beef extract peptone broth and cultured at 37±1℃ with shaking at 150 rpm for 24 h; Candida albicans was inoculated into malt extract broth and cultured at 30±1℃ with shaking at 150 rpm for 24 h.

[0074] The samples from Example 1 and Comparative Example 2 were dissolved in DMAc and deionized water, respectively, to prepare solutions of 10 mg / mL. Each solution was placed in a sterile petri dish, and approximately 15 mL of culture medium was added per dish (bacteria in beef extract peptone medium, fungi in malt extract agar, the same below). The mixture was thoroughly mixed to achieve final concentrations of 0.1, 0.25, 0.5, 0.75, 1.0, and 1.25 mg / mL, respectively. The test strains were then inoculated using the spread plating method and incubated upside down in a biochemical incubator (bacteria 37±1℃, fungi 28±1℃) for 24 h for bacteria and 38 h for fungi. Pure DMAc solvent without copolymers and deionized water without monomers served as negative controls, with all other experimental conditions and methods remaining the same. The inhibition rate was calculated by colony counting, and the lowest concentration at which complete sterility was achieved was defined as the minimum inhibitory concentration (MIC). The calculation results are listed in Table 3.

[0075] Table 3. Antibacterial rates (%) of different concentrations of Sample 1 and Comparative Example 2

[0076]

[0077] As shown in Table 3, the antibacterial rate increases with increasing concentration, and at the same concentration, Example 1 exhibits superior antibacterial activity compared to Comparative Example 2. At a concentration of 1.25 mg / mL, Comparative Example 2 showed antibacterial rates of 80.2%, 77.3%, and 85.2% against *Escherichia coli*, *Staphylococcus aureus*, and *Candida albicans*, respectively, while Example 1 achieved 100% antibacterial activity against all three species. This indicates that PLA possesses certain antibacterial capabilities, but the quaternary ammonium salt-GMA copolymer blend with PLA / PBAT exhibits better antibacterial performance than the PLA / PBAT blend alone. Using the same method, the antibacterial activity of Comparative Example 3 was tested, and it was significantly inferior to that of Example 1. At a concentration of 1.25 mg / mL, the antibacterial rates against *Escherichia coli*, *Staphylococcus aureus*, and *Candida albicans* were 85.6%, 74.7%, and 87.5%, respectively.

[0078] To verify the antibacterial stability of the nanocomposite antibacterial membrane material of Example 1, the nanocomposite antibacterial membrane material of Example 1 was washed and subjected to antibacterial tests. It was washed with water 50 and 100 times, and then the antibacterial test was carried out according to the method used in Example 1 above. The membrane material after washing was used to prepare a culture medium and test the antibacterial properties. The results obtained were consistent with those in Table 1, which can prove the stability of the antibacterial performance of the nanocomposite antibacterial material of the present invention.

[0079] Furthermore, to verify the sample performance of Examples 2 to 11, the antibacterial properties of the samples obtained in Examples 2 to 11 were tested with reference to Example 1. The results were basically the same as those of Example 1. The culture medium prepared with a concentration of 1.25 mg / mL in each example achieved 100% antibacterial effect and exhibited stable antibacterial performance. This indicates that the quaternary ammonium salt-GMA copolymer of the present invention can all act as chain extender compatibilizers, while introducing antibacterial functional groups to achieve highly efficient and stable antibacterial effects.

[0080] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A method for preparing PLA / PBAT / nanocomposite antibacterial film material, characterized in that, The method comprises the following steps: S1, monomer intercalation Mixing copolymerizable quaternary ammonium salt monomer compound with unsaturated double bonds and glycidyl methacrylate, adding organic nanometer montmorillonite, mechanically stirring and / or ultrasonic oscillation to make part of the mixture of quaternary ammonium salt monomer compound and glycidyl methacrylate enter the layered nanospace of the organic nanometer montmorillonite; S2, in-situ polymerization Dissolving sodium dodecyl sulfate in deionized water, adding the mixture obtained by monomer intercalation in step S1, adding aqueous solution of persulfate as initiator after heating to a set temperature to form a composite emulsion, then demulsifying with saturated brine, washing, suction filtering and drying to obtain organic nanometer montmorillonite / quaternary ammonium salt-GMA copolymer; S3, blending modification Blending polylactic acid, polybutylene adipate terephthalate and organic nanometer montmorillonite / quaternary ammonium salt-GMA copolymer through an extruder at 145-175℃, plasticizing, extruding and granulating, then drying to obtain PLA / PBAT / nanocomposite antibacterial film material; Wherein, the mass fraction of polylactic acid is 5-95 parts, the mass fraction of polybutylene adipate terephthalate is 5-95 parts, and the mass fraction of organic nanometer montmorillonite / quaternary ammonium salt-GMA copolymer is 0.1-10 parts.

2. The method of claim 1, wherein the PLA / PBAT / nanocomposite antimicrobial film material is prepared by the steps of: The quaternary ammonium salt monomer compound is at least one selected from the group consisting of vinylbenzyl dimethyl n-octyl ammonium salt, vinylbenzyl dimethyl n-decyl ammonium salt, vinylbenzyl dimethyl n-dodecyl ammonium salt, vinylbenzyl dimethyl n-hexadecyl ammonium salt, 2-acryloyloxyhexyl trimethyl ammonium salt, 2-methacryloyloxyethyl trimethyl ammonium salt, acrylamidopropyl trimethyl ammonium salt, methacrylic acid aminopropyl trimethyl ammonium salt, acrylic acid oxyalkyl pyridinium salt and methacryloyloxyalkyl pyridinium salt.

3. The method for preparing the PLA / PBAT / nanocomposite antibacterial membrane material according to claim 1, characterized in that, The organic nanometer montmorillonite is chemically pure, and the ion exchange capacity (CEC) is 110-120 mml / 100g.

4. The method of claim 1, wherein the PLA / PBAT / nanocomposite antimicrobial film material is prepared by the steps of: The persulfate is potassium persulfate, ammonium persulfate or sodium persulfate.

5. The method of claim 1, wherein the PLA / PBAT / nanocomposite antimicrobial film material is prepared by the steps of: In step S1, the mass ratio of glycidyl methacrylate, quaternary ammonium salt monomer compound and organic nanometer montmorillonite is 1:1:0.05-0.5; and / or, in step S2, the mass ratio of sodium dodecyl sulfate to the mixture of step S1 is 1:10-100.

6. The method of claim 1, wherein the PLA / PBAT / nanocomposite antimicrobial film material is prepared by the steps of: In step S1, when only mechanical stirring is used, the stirring speed is greater than 800 rpm, and the time is greater than 5 min; when only ultrasonic oscillation is used, the ultrasonic power is greater than 20 kHz, and the time is greater than 5 min.

7. The method for preparing the PLA / PBAT / nanocomposite antibacterial membrane material according to claim 1, characterized in that, In step S2, the reaction is carried out in a three-necked flask equipped with a stirrer, a reflux condenser and a thermometer.

8. The method for preparing the PLA / PBAT / nanocomposite antibacterial membrane material according to claim 1, characterized in that, The mass percentage concentration of the saturated brine is 5-10%.

9. A PLA / PBAT / nanocomposite antimicrobial film material, characterized in that, The preparation method is prepared by any one of claims 1-8.

10. Use of the PLA / PBAT / nanocomposite antibacterial film material of claim 9 as an antibacterial film.

Images