ADR chain extender modified poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) as well as preparation method and application thereof

Abstract

The invention provides an ADR chain extender modified poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) as well as a preparation method and application of the ADR chain extender modified poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate). According to the preparation method, the full bio-based antibacterial film can be prepared by blending the poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer modified by the ADR chain extender and the epoxidized soybean oil modified starch. Wherein the epoxidized soybean oil modified starch is of a core-shell structure, and due to the existence of a shell, the starch can be prevented from absorbing water, the water resistance of the full-bio-based antibacterial film is improved, and the shelf life is prolonged. Meanwhile, after the poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer is modified by the ADR chain extender, the molecular weight can be remarkably increased, so that the tear resistance and tensile strength of the full-bio-based antibacterial film can be remarkably improved, and meanwhile, the full-bio-based antibacterial film can have excellent antibacterial performance.

Description

Technical Field

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

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

[0003] Starch is a natural substance extracted from grains. As a biodegradable plastic, it is an economical and renewable alternative. However, the direct application of starch as a packaging material is limited by its insufficient mechanical properties and low thermal stability. Studies have reported that plasticizers can be dispersed in starch molecular chains, weaken hydrogen bonds under shear and high temperature, destroy the crystallization of starch, and make it thermoplastic. At the same time, plasticizers can be combined with some other modifiers to 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 glucosidase-modified starch by a solution method and casts it into a film. After testing, the prepared starch film has good anti-aging properties, which better solves the disadvantages of starch film being easily aged and brittle during storage or use, and has high tensile strength and elongation at break. CN116675883A discloses an octenyl succinic acid starch ester (OSA) modified high-amylose starch-based hydrophobic film. In this method, high-amylose starch is modified with octenyl succinic anhydride (OSA) reagent under weak alkaline conditions to obtain OSA-modified high-amylose starch film with good hydrophobicity. Compared with ordinary starch film, the barrier property and hydrophobicity 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 (PHA) are synthesized by soil microorganisms and used as intracellular storage substances. Objects made from these polymers are generally recognized as food sources by soil microorganisms. 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 of the invention

[0005] In view of this, the object of the present invention is to provide an ADR chain extender modified poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) and its preparation method and application. The all-biobased antibacterial film obtained from the above ADR chain extender modified poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) as a raw material has excellent mechanical properties and antibacterial 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 by an ADR chain extender, comprising the following steps:

[0012] The ADR chain extender is 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 by 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) and 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 acid anhydride content of the modified starch is 0.5-1.0 wt%.

[0020] Preferably, the preparation raw materials also include auxiliary agents.

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

[0022] In a fourth aspect, the present invention provides a method for preparing the above-mentioned all-biobased antibacterial film, comprising the following steps:

[0023] The poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) modified by the ADR chain extender, the modified starch and the optional auxiliary agent are mixed, extruded and film-formed to obtain a fully bio-based antibacterial film.

[0024] Preferably, the extrusion temperature is 150-160°C.

[0025] In a fifth aspect, the present invention provides a packaging film formed by the all-biobased antibacterial film involved in the above technical solution.

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

[0027] The present invention provides a method for preparing a fully bio-based poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) antibacterial film by blending a poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer modified by an ADR chain extender and epoxy soybean oil-modified starch. The epoxy soybean oil-modified starch is a core-shell structure, and the presence of the shell can prevent the starch from absorbing water, thereby improving the water resistance of the fully bio-based antibacterial film and extending the shelf life. At the same time, after the poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer is modified by an ADR chain extender, the molecular weight can be significantly increased, thereby significantly improving the tear resistance and tensile strength of the fully bio-based antibacterial film, and at the same time, the fully bio-based antibacterial film can have excellent antibacterial properties.

[0028] According to tests, the all-biobased antibacterial film provided by the present invention has a tensile strength of >17 MPa, an elongation at break of >290%, a tear strength of >80 kN / m, a water absorption rate of <12%, and an antibacterial property of >50%. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1is the SEM image of unmodified starch;

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

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] First, the present invention provides a poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) modified by an ADR chain extender.

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

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

[0035] In some embodiments of the present invention, 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; 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, specifically 1:1000, 1.5:1000, 2:1000, 2.5:1000 or 3:1000. The molecular weight of the poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) modified by the ADR chain extender is 1.5×10 5 ~2.0×10 5 g mol -1 , specifically 1.5×10 5 g mol -1 , 1.7×10 5 g mol -1 , 2×10 5 g mol -1 wait.

[0036] The present invention has no particular limitation on the source of the ADR chain extender, and any common commercial 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 generate 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, 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 showing excellent antibacterial properties.

[0041] The present invention also provides a modified starch, wherein the modified starch is starch modified by 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 epoxy soybean oil. The starch may be any one or more of cassava 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] To prepare the starch (ST) solution, take starch, add DMSO solution (15 mL), and stir at 130 ° C for 5 h in a 50 mL single-necked flask equipped with a magnetic stirring bar. On the other hand, add a drop of hydrochloric acid to a 50 mL double-necked flask equipped with a magnetic stirring bar, and then drop epoxidized soybean oil (ESO) into the solution. Then increase the temperature of the resulting final reaction mixture to 80 ° C and stir for 24 h under N2 atmosphere. At the end of the given reaction time, pour the desired ST-ESO solution into a petri dish, rinse it with hot toluene several times to remove the unreacted ESO, and finally dry it under reduced pressure at 60 ° C for 1 day.

[0045] In the present invention, the ratio of the mass of the starch to the mass of the epoxy compound is 1:(0.5-1.5), such as 1:0.5, 1:1, 1:1.5, etc. For example, if the starch is 1 part, the epoxy compound can be 0.5 part, 1 part or 1.5 parts, etc.

[0046] In the present invention, if the acid anhydride content is too low, the activity is insufficient, and if it is too high, the starch is prone to hardening. Therefore, after screening, the present invention preferably has an acid anhydride content of 0.5-1.0wt%, and more preferably 0.85wt%.

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

[0048] It should be noted that the starch surface has some holes. The present invention uses epoxidized soybean oil to modify it, so that a thin film can be formed on the starch surface, so that the modified starch has a core-shell structure, wherein the starch is a rigid core and the epoxidized soybean oil is a flexible shell. According to tests, the shell of the modified starch can prevent the starch from absorbing water, improve the water resistance of the subsequently prepared film, and extend the shelf life.

[0049] The present invention also provides a fully bio-based antibacterial film, the raw materials for preparing the film include the poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) modified by the ADR chain extender and modified starch.

[0050] In some preferred embodiments of the present invention, the raw materials for preparing the all-biobased antimicrobial 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 stearic acid amide (abbreviated as: EBS), the antioxidant can be selected from antioxidant 168 and / or antioxidant 1010, and the dispersant can be selected from monoanhydride esters, calcium stearate, etc.

[0051] The present invention also provides a method for preparing the above-mentioned all-biobased antibacterial film, comprising the following steps:

[0052] The poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) modified by the ADR chain extender, the modified starch and the optional auxiliary agent 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 dried at 80°C in advance, and then the ADR chain extender-modified poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate), modified starch and optional auxiliary agents are weighed in proportion, and the weighed components are fully mixed in a high-speed mixer, and then extruded and granulated at 150-160°C using a twin-screw extruder, with a screw speed of 150-400rpm, preferably 200rpm, to obtain a blend. Finally, the pellets are blown into a film, and the temperature of the single-screw film blowing machine is 160-180°C, and the screw speed is 60-100rpm, preferably 70rpm.

[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 by ADR chain extender and epoxy soybean oil modified starch. Among them, the epoxy soybean oil modified starch is a core-shell structure, and the presence of the shell can prevent the starch from absorbing water, improve the water resistance of the all-biobased antibacterial film, and extend the shelf life. At the same time, after the poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) polymer is modified by the 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] According to tests, the all-biobased antibacterial film provided by the present invention has a tensile strength of >17 MPa, an elongation at break of >290%, a tear strength of >80 kN / m, a water absorption rate of <12%, and an antibacterial property of >50%.

[0059] Based on this, the present invention provides a packaging film formed by the above-mentioned all-biobased antibacterial film. Specifically, the packaging film can be used to package food and medical-grade materials.

[0060] To further illustrate the present invention, the following examples are used to explain the present invention in detail. The starch used in the following examples of the present invention is corn starch, which is provided by COFCO Biomaterials Co., Ltd.; P(3HB-co-3HH X ) (BP330) was purchased from Jiangsu Lansu Biomaterial Co., Ltd.; Epoxidized soybean oil was purchased from Nantong Haierma Technology Co., Ltd.; other components were not restricted to the source of purchase. The extruder was provided by Nanjing Keya Chemical Equipment Co., Ltd.; the single-screw film blowing machine was provided by Dalian Zhenghuayang Plastic Machinery Co., Ltd.

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

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

[0063] First, P(3HB-co-3HH X ) was dried at 80°C, and then 0.1% of ADR-4368 chain extender and P(3HB-co-3HH X ) was extruded by a twin-screw extruder at 160°C and 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 other parameters and steps are consistent with Preparation Example 1.

[0066] Preparation Example 3-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 other parameters and steps are consistent with Preparation Example 1.

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

[0069] Compared with Preparation Example 1, the only difference is that the ADR-4368 chain extender is replaced by an ADR-4385 chain extender in equal amounts, and the other parameters and steps are consistent with Preparation Example 1.

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

[0071] To prepare a starch (ST) solution, take 1 part of starch, add DMSO solution (15 mL), and stir at 130°C for 5 h in a 50 mL single-necked flask equipped with a magnetic stirring bar. On the other hand, add a drop of hydrochloric acid to a 50 mL double-necked flask equipped with a magnetic stirring bar, and then drop epoxidized soybean oil (0.5 parts per 1 part of starch) (ESO) into the solution. Then, the temperature of the resulting final reaction mixture was raised to 80°C and stirred for 24 h under a N2 atmosphere. After reacting for 29 h, 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 ST-ESO-0.5.

[0072] SEM images of unmodified starch are shown in Figure 1 There are holes on the starch surface. The SEM image of the modified core-shell structure starch is shown in Figure 2 , the hole disappears. Figure 1 and Figure 2 It can be seen from the comparison that the pores on the starch surface disappeared after the reaction, indicating that a core-shell structure was formed.

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

[0074] The difference from Preparation Example 5 is that the amount of ESO used is 1 part, and the other parameters and steps are consistent with Preparation Example 5. The obtained product is recorded as ST-ESO-1 (ST / ESO (n / n) = 1:1).

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

[0076] The difference from Preparation Example 5 is that the amount of ESO used is 1.5 parts, and the other parameters and steps are consistent with Preparation Example 5. The obtained product is recorded as ST-ESO-1.5.

[0077] Example 1

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

[0079] Preparation method: Modified P(3HB-co-3HH X) is dried at 80°C in advance, and then the materials are weighed according to the above proportions, and the above weighed components are fully mixed in a high-speed mixer, and then extruded and granulated at 160°C with a twin-screw extruder, and the screw speed is 200rpm to obtain a blend. Finally, the pellets are blown into a film, and the temperature of the single-screw film blowing machine is 160°C and the screw speed is 70rpm.

[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 ) was dried at 80°C in advance, and then the materials were weighed according to the above proportions, and the above weighed components were fully mixed in a high-speed mixer, and then extruded and granulated at 160°C using a twin-screw extruder, and the screw speed was 200rpm. Finally, the pellets were blown into films, and the temperature of the single-screw film blowing machine was 160°C and the screw speed was 70rpm.

[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 ) is dried at 80°C in advance, and then the materials are weighed according to the above proportions, and the above weighed components are fully mixed in a high-speed mixer, and then extruded and granulated at 160°C with a twin-screw extruder, and the screw speed is 200rpm to obtain a blend. Finally, the pellets are blown into a film, and the temperature of the single-screw film blowing machine is 160°C and the screw speed is 70rpm.

[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 proportions, and the above weighed components were fully mixed in a high-speed mixer, and then extruded and granulated at 160°C with a twin-screw extruder, and the screw speed was 200rpm to obtain a blend. Finally, the pellets were blown into films, and the temperature of the single-screw film blowing machine was 170°C and the screw speed was 70rpm.

[0089] Example 5

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

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

[0092] Example 6

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

[0094] Example 7

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

[0096] Example 8

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

[0098] Comparative Example 1

[0099] Formula: 50 parts P(3HB-co-3HH X )(BP330), 50 parts of modified starch with core-shell structure.

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

[0101] Comparative Example 2

[0102] Formula: modified starch with a single core-shell structure. The preparation method is as in the example.

[0103] Performance Testing

[0104] The performance test was carried out on the products obtained in the above Examples 1 to 5 and Comparative Examples 1 to 2, and the test method was as follows:

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

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

[0107] (3) Antibacterial performance test method is:

[0108] The method studies the antibacterial activity of the sample against Staphylococcus aureus (ATCC 6538). Specifically, Staphylococcus aureus is cultured in a broth solution (tryptic soy broth for Staphylococcus aureus) at 37°C for 24 hours. The killing ability of the films obtained in Examples 1 to 5 and Comparative Examples 1 to 2 against adherent bacteria is evaluated by the coating plate method. The obtained film products are then spread on an agar plate. After incubation at 37°C for 24 hours, the number of colonies on the plate is calculated, and then the percentage is calculated.

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

[0110] Table 1

[0111]

[0112]

[0113] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A poly(-3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with an ADR chain extender, characterized in that: It is prepared by modifying poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) with ADR chain extender.

2. The ADR chain extender modified poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) according to claim 1, 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 .

3. A method for preparing the ADR chain extender modified poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) as claimed in claim 1 or 2, characterized in that: The following steps are involved: The ADR chain extender is mixed with poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) and then melt extruded.

4. The preparation method according to claim 3, characterized in that: The temperature of the melt extrusion is 155-165°C.

5. A fully bio-based antibacterial membrane, characterized in that: The preparation raw materials include poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) modified by ADR chain extender and modified starch; The modified starch is starch modified by epoxy compounds.

6. The all-biobased antimicrobial membrane according to claim 5, characterized in that: The mass ratio of the ADR chain extender modified poly (-3-hydroxybutyrate-co-3-hydroxyhexanoate) and the modified starch is (100-50): (0-50); The epoxy compound is selected from epoxidized soybean oil; 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%.

7. The all-biobased antibacterial membrane according to claim 5 or 6, characterized in that: The preparation raw materials also include auxiliary agents; The auxiliary agent includes any one or more of a lubricant, an opening agent, an antioxidant or a dispersant.

8. A method for preparing a fully bio-based antibacterial film as claimed in 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, the modified starch and the optional auxiliary agent 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°C.

10. A packaging film, characterized in that: The method 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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