An adr chain extender modified poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) and its preparation method and application

Abstract

The application provides an ADR chain extender modified poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) and a preparation method and application thereof. The full-biological antibacterial film can be prepared by blending the ADR chain extender modified poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer and the epoxy soybean oil modified starch. The epoxy soybean oil modified starch has a core-shell structure, the existence of the shell can prevent the starch from absorbing water, improve the water resistance of the full-biological antibacterial film, and prolong the shelf life. Meanwhile, after the poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer is modified by the ADR chain extender, the molecular weight can be significantly increased, so that the tear resistance and tensile strength of the full-biological antibacterial film can be obviously improved, and the full-biological antibacterial film also has excellent antibacterial performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food packaging, and particularly relates to an ADR chain extender modified poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) and a preparation method and application thereof. BACKGROUND

[0002] Petrochemical derived plastics, such as polyethylene (PE), vinyl acetate (EVA), polyamide (PA), polypropylene (PP), polystyrene (PS) or polyethylene terephthalate (PET), etc., are widely used as packaging materials due to their cost advantage, availability and excellent properties, such as good barrier performance, flexibility, strength and durability, etc. However, according to statistics, the global plastic waste recycling rate is only 9.3%. Therefore, in order to avoid pollution caused by plastics, it is imperative to explore degradable materials that can be used as packaging materials

[0003] Starch is a natural substance extracted from grains and is an economical and renewable alternative as a biodegradable plastic. However, the direct application of starch as a packaging material is limited by its insufficient mechanical properties and low thermal stability. It has been reported that plasticizers can be dispersed in the starch molecular chain, weakening hydrogen bonds and destroying the crystallization of starch under the action of shear and high temperature, so that starch has thermoplasticity. At the same time, plasticizers combined with some other modifiers can effectively improve the flexibility of thermoplastic starch (TPS). For example, CN116589718A discloses an anti-aging starch film and a preparation method thereof. The method obtains a glucosidase modified starch by a solution method and casts a film. The prepared starch film has good anti-aging performance, better solves the problem of easy aging and brittleness of the starch film during storage or use, and also has high tensile strength and elongation at break. CN116675883A discloses a high amylose starch-based hydrophobic film modified by octenyl succinic anhydride starch (OSA). The method modifies high amylose starch with an octenyl succinic anhydride (OSA) reagent under weak alkaline conditions to obtain an OSA modified high amylose starch film with good hydrophobicity. Compared with ordinary starch film, the barrier and hydrophobic properties of the obtained film are greatly improved. It can be seen that starch is widely used in the preparation of packaging films.

[0004] Biodegradable polymers polyhydroxyalkanoates (abbreviated as PHA) are synthesized by soil microorganisms and used as intracellular storage substances. The articles made from these polymers are generally recognized by soil microorganisms as food sources. Poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB-co-3HHx) is a special biodegradable PHA copolymer with high elongation at break but low tensile strength. SUMMARY

[0005] In view of this, the present invention aims to provide an ADR chain extender-modified poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), its preparation method, and its application. The fully bio-based antimicrobial film obtained from the ADR chain extender-modified poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) exhibits excellent mechanical and antimicrobial properties.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an ADR chain extender-modified poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), which is formed by modifying poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with an ADR chain extender.

[0008] Preferably, the ADR chain extender is selected from any one or more of ADR-4368 chain extender, ADR-4370 chain extender, ADR-4468 chain extender or ADR-4385 chain extender.

[0009] Preferably, the ratio of the amount of the ADR chain extender to the mass of the poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) is (1-3):1000.

[0010] Preferably, the molecular weight of the ADR chain extender modified poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) is 1.5×10 5 ~2.0×10 5 g mol -1 .

[0011] In a second aspect, the present invention provides a method for preparing poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with an ADR chain extender, comprising the following steps:

[0012] The ADR chain extender was mixed with poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) and then melt-extruded.

[0013] Preferably, the temperature of the melt extrusion is 155-165°C.

[0014] In a third aspect, the present invention provides a fully bio-based antimicrobial film, the raw materials for its preparation include poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with an ADR chain extender and modified starch;

[0015] The modified starch is starch modified by epoxy compounds.

[0016] Preferably, the mass ratio of the ADR chain extender-modified poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) to the modified starch is (100-50):(0-50).

[0017] Preferably, the epoxy compound is selected from epoxidized soybean oil.

[0018] Preferably, the ratio of the mass of the starch to the mass of the epoxy compound is 1:(0.5-1.5).

[0019] Preferably, the anhydride content of the modified starch is 0.5-1.0 wt%.

[0020] Preferably, the preparation raw material further comprises an auxiliary agent.

[0021] Preferably, the auxiliary agent comprises any one or more of a lubricant, an opening agent, an antioxidant, or a dispersant.

[0022] In a fourth aspect, the present application provides a preparation method of the above-mentioned full-bio-based antibacterial film, comprising the following steps:

[0023] After mixing the ADR chain extender modified poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate), the modified starch, and the optional auxiliary agent, extruding, film forming, a full-bio-based antibacterial film is obtained.

[0024] Preferably, the temperature of the extrusion is 150-160℃.

[0025] In a fifth aspect, the present application provides a packaging film formed by the full-bio-based antibacterial film according to the above technical solution.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] The present application provides that by using ADR chain extender modified poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer and epoxidized soybean oil modified starch blending, a full-bio-based poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) antibacterial film can be prepared. Among them, the epoxidized soybean oil modified starch is a core-shell structure, the existence of the shell can prevent the starch from absorbing water, can improve the water resistance of the full-bio-based antibacterial film, and prolong the shelf life. At the same time, the molecular weight of the poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer modified by the ADR chain extender can be significantly increased, thereby the tear resistance and tensile strength of the full-bio-based antibacterial film can be significantly improved, and the full-bio-based antibacterial film also has excellent antibacterial performance.

[0028] After testing, the tensile strength of the full-bio-based antibacterial film provided by the present application is >17MPa, the elongation at break is >290%, the tear strength is >80kN / m, the water absorption rate is <12%, and the antibacterial performance is >50%. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1SEM image of unmodified starch;

[0030] Figure 2 SEM image of modified core-shell structured starch in Preparation Example 5. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] Firstly, the present application provides an ADR chain extender modified poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate).

[0033] In some embodiments of the present application, the preparation method of the ADR chain extender modified poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) is as follows:

[0034] After mixing the ADR chain extender with poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) (i.e., P3HB-co-3HHx), melt extrusion is performed. The melt base is preferably performed in a twin-screw extruder, with a temperature of 155-165°C, preferably 160°C; and a rotation speed of 100-300 rpm, preferably 200 rpm.

[0035] In some embodiments of the present application, the ADR chain extender is selected from any one or more of ADR-4368 chain extender, ADR-4370 chain extender, ADR-4468 chain extender or ADR-4385 chain extender, preferably ADR-4370 chain extender; and the ratio of the amount of the ADR chain extender to the mass of the poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) in the above preparation method is (1-3):1000, which can be specifically 1:1000, 1.5:1000, 2:1000, 2.5:1000 or 3:1000, etc. The molecular weight of the ADR chain extender modified poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) is 1.5×10 5 ~ 2.0×10 5 g / mol -1 , which can be specifically 1.5×10 5 g / mol -1 , 1.7×10 5 g / mol -1 , 2×10 5 g / mol -1 , etc.

[0036] The present invention has no particular limitation on the source of the ADR chain extender, and any commercially available product may be used.

[0037] In the present invention, the specific reaction process of using ADR chain extender to modify P3HB-co-3HHx is as follows:

[0038]

[0039] In the above reaction process, the epoxy functional group in ADR reacts with P(3HB-co-3HH X ) undergoes a ring-opening reaction to form a chain extension or network structure, making P(3HB-co-3HH X ) molecular weight is increased, thereby improving the tear resistance and tensile strength of the film prepared subsequently, so that the film has excellent mechanical properties. X ) modification, and can also improve the starch and P(3HB-co-3HH X ) resins, further improving the mechanical properties of the film prepared subsequently.

[0040] Furthermore, the phenol group on the ADR chain can destroy the structure of bacterial cell walls and cell membranes, causing the matrix, alkaline phosphatase, inorganic ions and soluble proteins to leak into the bacterial culture medium, thereby leading to bacterial death. X )’s high specific surface area increases the interaction between bacteria and lipoic acid, phosphate groups or hydroxyl groups, which is beneficial to the destruction of bacterial cells, thus exhibiting excellent antibacterial properties.

[0041] The present invention also provides a modified starch, wherein the modified starch is starch modified with an epoxy compound, and the starch obtained after modification can have certain antibacterial properties.

[0042] In some embodiments of the present invention, the epoxy compound is preferably epoxidized soybean oil. The starch can be any one or more of tapioca starch, corn starch, potato starch or wheat starch.

[0043] In some embodiments of the present invention, the modified starch is prepared according to the following method:

[0044] A starch (ST) solution was prepared by taking starch, adding a DMSO solution (15 mL) in a 50 mL single-necked flask equipped with a magnetic stir bar, and stirring at 130°C for 5 h. On the other hand, a drop of hydrochloric acid was added to a 50 mL double-necked flask equipped with a magnetic stir bar, and then epoxy soybean oil (ESO) was added dropwise to the solution. The temperature of the resulting final reaction mixture was then increased to 80°C, and stirring was performed under an N2 atmosphere for 24 h. At the end of the given reaction time, the desired ST-ESO solution was poured into a petri dish, rinsed several times with hot toluene to remove unreacted ESO, and finally dried under reduced pressure at 60°C for 1 day to obtain the product.

[0045] In the present application, the ratio of the mass of the starch to the mass of the epoxide compound is 1:(0.5-1.5), such as 1:0.5, 1:1, 1:1.5, etc. If the starch is 1 part, the epoxide compound can be 0.5 parts, 1 part, or 1.5 parts, etc.

[0046] In the present application, if the anhydride content is too low, the activity is not enough, and conversely, if it is too high, the starch is prone to caking. Therefore, through screening, the present application preferably has an anhydride content of 0.5-1.0 wt%, more preferably 0.85 wt%.

[0047] The parameters in the above preparation method, such as temperature, time, amount, etc. can be adjusted within a reasonable range.

[0048] It should be noted that the surface of the starch has some pores, and the present application can form a thin film on the surface of the starch by modifying it with epoxy soybean oil, so that the modified starch has a core-shell structure, in which the starch is a rigid core and the epoxy soybean oil is a flexible shell. Tests have shown that the shell of the modified starch can prevent the starch from absorbing water, improve the water resistance of the subsequently prepared film, and prolong the shelf life.

[0049] The present application also provides a full-bio-based antibacterial film, which is prepared from the above-mentioned ADR chain extender modified poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) and modified starch.

[0050] In some preferred embodiments of the present application, the preparation raw materials of the full-bio-based antibacterial film further include some auxiliary agents, which can be selected from any one or more of lubricants, opening agents, antioxidants, or dispersants. For example, the lubricant can be selected from erucic acid amide EA, the opening agent can be selected from ethylene bis-stearamide (abbreviated as: EBS), the antioxidant can be selected from antioxidant 168 and / or antioxidant 1010, and the dispersant can be selected from monoanhydride ester, calcium stearate, etc.

[0051] The present application also provides a preparation method of the above-mentioned full-bio-based antibacterial film, which comprises the following steps:

[0052] The poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) modified by the ADR chain extender, modified starch and optional auxiliary agents are mixed, extruded and film-formed to obtain a fully bio-based antibacterial film.

[0053] In the present invention, the film-making method is not particularly limited, and specifically, the film can be blown by a single-screw film blowing machine.

[0054] In the above-mentioned preparation method of the present invention, the mass ratio of the ADR chain extender-modified poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) and the modified starch during feeding is (100-50): (0-50), such as 99:1, 95:5, 90:10, 85:15, 80:20, 75:25, 70:30, 65:35, 60:40, 55:45, 50:50, etc.

[0055] In the present invention, when an auxiliary agent is added, the amount of the auxiliary agent is 1 to 5 wt% of the poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) and modified starch blend, such as 1 wt%, 2 wt%, 3 wt%, 4 wt% or 5 wt%.

[0056] In some preferred embodiments of the present invention, the modified P(3HB-co-3HH X ) is pre-dried at 80°C, and then ADR chain extender-modified poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), modified starch, and optional additives are weighed in proportion. The weighed components are thoroughly mixed in a high-speed mixer, and then extruded into pellets using a twin-screw extruder at 150-160°C at a screw speed of 150-400 rpm, preferably 200 rpm, to obtain a blend. Finally, the pellets are blown into films using a single-screw film blowing machine at a temperature of 160-180°C and a screw speed of 60-100 rpm, preferably 70 rpm.

[0057] The above-mentioned all-biobased antibacterial film provided by the present invention is prepared by blending poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer modified with an ADR chain extender and epoxy soybean oil-modified starch. Among them, the epoxy soybean oil-modified starch has a core-shell structure. The presence of the shell can prevent the starch from absorbing water, thereby improving the water resistance of the all-biobased antibacterial film and extending the shelf life. At the same time, after the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer is modified with an ADR chain extender, the molecular weight can be significantly increased, thereby significantly improving the tear resistance and tensile strength of the all-biobased antibacterial film, and at the same time, the all-biobased antibacterial film can have excellent antibacterial properties.

[0058] The all-bio-based antibacterial film provided by the application has a tensile strength of >17 MPa, an elongation at break of >290%, a tear strength of >80 kN / m, a water absorption of <12%, and an antibacterial performance of >50% after testing.

[0059] Based on this, the application provides a packaging film formed by the all-bio-based antibacterial film described above. Specifically, the packaging film can package food and medical-grade materials.

[0060] To further illustrate the application, the following examples are used for detailed description. The starch used in the following examples of the application is corn starch provided by COFCO Bio-materials Co., Ltd.; P(3HB-co-3HH X )(BP330) is purchased from Jiangsu Lansu Biomaterials Co., Ltd.; epoxy soybean oil is purchased from Nantong Haileyuoma Technology Co., Ltd.; and other components are not limited in the source of purchase. The extruder is provided by Nanjing Keya Chemical Equipment Co., Ltd.; and the single-screw film blowing machine is provided by Dalian Zhenghuayang Plastic Machinery Co., Ltd.

[0061] Preparation Example 1-Preparation of modified P(3HB-co-3HH X )

[0062] Modified P(3HB-co-3HH X ) is prepared by a melt extrusion method, and the steps are as follows:

[0063] First, P(3HB-co-3HH X ) is dried at 80°C, and then 0.1% of the ADR-4368 chain extender and P(3HB-co-3HH X ) are extruded through a twin-screw extruder at 160°C and a rotation speed of 200 rpm to obtain modified P(3HB-co-3HH X ).

[0064] Preparation Example 2

[0065] Compared with Preparation Example 1, the only difference is that the ADR-4368 chain extender is replaced by an equal amount of ADR-4370 chain extender, and the remaining parameters and steps remain the same as those of Preparation Example 1.

[0066] Preparation Example 3-Preparation of modified P(3HB-co-3HH X )

[0067] Compared with Preparation Example 1, the only difference is that the ADR-4368 chain extender is replaced by an equal amount of ADR-4468 chain extender, and the remaining parameters and steps remain the same as those of Preparation Example 1.

[0068] Preparation Example 4-Preparation of modified P(3HB-co-3HH X )

[0069] The difference compared with Preparation Example 1 is that the ADR-4368 chain extender is replaced by ADR-4385 chain extender in equivalent amount, and the rest of the parameters and steps remain the same as Preparation Example 1.

[0070] Preparation Example 5 - Preparation of modified starch with core-shell structure

[0071] A starch (ST) solution was prepared by taking 1 part of starch and adding DMSO solution (15 mL) in a 50 mL single neck flask equipped with a magnetic stir bar and stirring at 130 °C for 5 h. On the other hand, a drop of hydrochloric acid was added to a 50 mL double neck flask equipped with a magnetic stir bar, and then epoxy soybean oil (ESO) was added dropwise into the solution (0.5 parts based on 1 part of starch). The temperature of the resulting final reaction mixture was then increased to 80 °C and stirred under N2atmosphere for 24 h. After 29 h of reaction, the desired ST-ESO solution was poured into a petri dish, rinsed several times with hot toluene to remove unreacted ESO, and finally dried under reduced pressure at 60 °C for 1 day. The product was labeled as ST-ESO-0.5.

[0072] The SEM image of unmodified starch is shown in Figure 1 , and the holes on the surface of the starch disappear, as shown in the SEM image of the modified starch with core-shell structure Figure 2 . The comparison of Figure 1 and Figure 2 shows that the holes on the surface of the starch after reaction disappear, indicating the formation of a core-shell structure.

[0073] Preparation Example 6 - Preparation of modified starch with core-shell structure

[0074] The difference from Preparation Example 5 is that the amount of ESO is 1 part, and the rest of the parameters and steps remain the same as Preparation Example 5, and the product obtained is labeled as ST-ESO-1 (ST / ESO (n / n) = 1:1).

[0075] Preparation Example 7 - Preparation of modified starch with core-shell structure

[0076] The difference from Preparation Example 5 is that the amount of ESO is 1.5 parts, and the rest of the parameters and steps remain the same as Preparation Example 5, and the product obtained is labeled as ST-ESO-1.5.

[0077] Example 1

[0078] Formulation: 90 parts of modified P(3HB-co-3HH X ) obtained from Preparation Example 1, 10 parts of modified starch with core-shell structure obtained from Preparation Example 5.

[0079] Preparation method: The modified P(3HB-co-3HH X) were pre-dried at 80°C. The materials were then weighed according to the above proportions and thoroughly mixed in a high-speed mixer. The blend was then extruded into pellets using a twin-screw extruder at 160°C and a screw speed of 200 rpm to obtain the blend. Finally, the pellets were blown into film using a single-screw film blowing machine at a temperature of 160°C and a screw speed of 70 rpm.

[0080] Example 2

[0081] Formula: 80 parts of modified P(3HB-co-3HH obtained in Preparation Example 1 X ), 20 parts of the modified starch with core-shell structure obtained in Preparation Example 6.

[0082] Preparation method: Modified P(3HB-co-3HH X ) were pre-dried at 80°C. The materials were weighed according to the above proportions and thoroughly mixed in a high-speed mixer. The blend was then extruded and pelletized using a twin-screw extruder at 160°C (200 rpm). The pellets were then blown into film using a single-screw film blowing machine at 160°C (70 rpm).

[0083] Example 3

[0084] Formula: 70 parts of modified P(3HB-co-3HH obtained in Preparation Example 1 X ), 30 parts of the modified starch with core-shell structure obtained in Preparation Example 7.

[0085] Preparation method: Modified P(3HB-co-3HH X ) were pre-dried at 80°C. The materials were then weighed according to the above proportions and thoroughly mixed in a high-speed mixer. The blend was then extruded into pellets using a twin-screw extruder at 160°C and a screw speed of 200 rpm to obtain the blend. Finally, the pellets were blown into film using a single-screw film blowing machine at a temperature of 160°C and a screw speed of 70 rpm.

[0086] Example 4

[0087] Formula: 60 parts of modified P(3HB-co-3HH obtained in Preparation Example 1 X ), 40 parts of the modified starch with core-shell structure obtained in Preparation Example 5.

[0088] Preparation method: Modified P(3HB-co-3HH X) was dried at 80°C in advance, and then the materials were weighed according to the above-mentioned proportions. The weighed components were mixed uniformly in a high-speed mixer, and then extruded and granulated in a twin-screw extruder at 160°C, with a screw rotation speed of 200 rpm, to obtain a blend. Finally, the granules were blown into a film, with a temperature of the single-screw film blowing machine being 170°C and a screw rotation speed being 70 rpm.

[0089] Example 5

[0090] Formulation: 50 parts of the modified P(3HB-co-3HH X ) obtained in Preparation Example 1, 50 parts of the core-shell structured modified starch obtained in Preparation Example 5.

[0091] Preparation method: The modified P(3HB-co-3HH X ) was dried at 80°C in advance, and then the materials were weighed according to the above-mentioned proportions. The weighed components were mixed uniformly in a high-speed mixer, and then extruded and granulated in a twin-screw extruder at 160°C, with a screw rotation speed of 200 rpm, to obtain a blend. Finally, the granules were blown into a film, with a temperature of the single-screw film blowing machine being 175°C and a screw rotation speed being 70 rpm.

[0092] Example 6

[0093] Compared with Example 1, the modified P(3HB-co-3HH X ) obtained in Preparation Example 1 was replaced by an equal amount of the modified P(3HB-co-3HH X ) obtained in Preparation Example 2, and the remaining parameters and steps were consistent with those of Example 1.

[0094] Example 7

[0095] Compared with Example 1, the modified P(3HB-co-3HH X ) obtained in Preparation Example 1 was replaced by an equal amount of the modified P(3HB-co-3HH X ) obtained in Preparation Example 3, and the remaining parameters and steps were consistent with those of Example 1.

[0096] Example 8

[0097] Compared with Example 1, the modified P(3HB-co-3HH X ) obtained in Preparation Example 1 was replaced by an equal amount of the modified P(3HB-co-3HH X ) obtained in Preparation Example 4, and the remaining parameters and steps were consistent with those of Example 1.

[0098] Comparative Example 1

[0099] Formulation: 50 parts of P(3HB-co-3HH X ) (BP330), 50 parts of the core-shell structured modified starch.

[0100] Preparation method: The unmodified P(3HB-co-3HH X ) was dried at 80°C in advance, and then the materials were weighed according to the above-mentioned proportions, and the weighed components were fully mixed in a high-speed mixer, and then extruded and granulated in a twin-screw extruder at 160°C, with a screw rotation speed of 200 rpm, to obtain the blend. Finally, the granules were blown into a film, with a temperature of the single-screw film blowing machine being 175°C, and a screw rotation speed being 70 rpm.

[0101] Comparative Example 2

[0102] Formulation: modified starch with single core-shell structure. The preparation method is referred to the example.

[0103] Performance test

[0104] The products obtained in Examples 1-5 and Comparative Examples 1-2 above were subjected to performance tests, and the test methods were as follows:

[0105] (1) Mechanical properties: tested according to the standard of GB / T 1010.3-2006;

[0106] (2) Water absorption test: tested by using a contact angle tester produced by Shanghai Fute Test Equipment Co., Ltd.;

[0107] (3) The antibacterial performance test method was as follows:

[0108] This method studied the antibacterial activity of the sample on Staphylococcus aureus (ATCC 6538). Specifically, Staphylococcus aureus was cultured in a broth solution (trypticase soy broth for Staphylococcus aureus) at 37°C for 24 h. The killing ability of the film obtained in Examples 1-5 and Comparative Examples 1-2 on the adherent bacteria was evaluated by using a spread plate method. Then the obtained film product was dispersed on an agar plate. After incubation at 37°C for 24 h, the number of colonies on the plate was calculated, and then the percentage was calculated.

[0109] The test results are shown in Table 1 below:

[0110] Table 1

[0111]

[0112]

[0113] The foregoing description of the disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fully bio-based antibacterial film, characterized in that: The raw materials for the preparation include poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with an ADR chain extender and modified starch; The modified starch is starch modified by an epoxy compound; the epoxy compound is selected from epoxidized soybean oil; and the modified starch has a core-shell structure.

2. The all-biobased antibacterial membrane according to claim 1, characterized in that: The mass ratio of the ADR chain extender-modified poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) to the modified starch is (99-50):(1-50); The ratio of the mass of the starch to the mass of the epoxy compound is 1:(0.5-1.5); The acid anhydride content of the modified starch is 0.5-1.0 wt %.

3. The all-biobased antibacterial membrane according to claim 1 or 2, characterized in that: The preparation raw materials also include auxiliary agents; The auxiliary agent includes any one or more of a lubricant, an anti-blocking agent, an antioxidant or a dispersant.

4. The all-biobased antimicrobial membrane according to any one of claims 1 to 3, characterized in that: The ADR chain extender-modified poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is formed by modifying poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with an ADR chain extender.

5. The all-biobased antimicrobial membrane according to claim 4, characterized in that: The ADR chain extender is selected from any one or more of ADR-4368 chain extender, ADR-4370 chain extender, ADR-4468 chain extender or ADR-4385 chain extender; The ratio of the amount of the ADR chain extender to the mass of the poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) is (1-3):1000; The molecular weight of the ADR chain extender modified poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) is 1.5×10 5 ~2.0×10 5 g mol -1 .

6. The all-biobased antimicrobial membrane according to any one of claims 1 to 5, characterized in that: The ADR chain extender-modified poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) was prepared according to the following method: The ADR chain extender was mixed with poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) and then melt-extruded.

7. The all-biobased antimicrobial membrane according to claim 6, characterized in that: The temperature of the melt extrusion is 155-165°C.

8. A method for preparing a fully bio-based antibacterial film according to any one of claims 5 to 7, characterized in that: The following steps are involved: The poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) modified by the ADR chain extender, modified starch and optional auxiliary agents are mixed, extruded and film-formed to obtain a fully bio-based antibacterial film.

9. The preparation method according to claim 8, characterized in that The extrusion temperature is 150~160 o C.

10. A packaging film, characterized in that: It is formed by the all-biobased antibacterial film according to any one of claims 5 to 7 or the all-biobased antibacterial film prepared by the preparation method according to claim 8 or 9.

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