阅读说明：本技术 一种高阻隔抗菌pbat聚合物及其制备方法和应用 (High-barrier antibacterial PBAT polymer and preparation method and application thereof ) 是由 朱敏 侯芳 江振林 朱科宇 徐晨雪 徐佳敏 范欣 于 2021-07-12 设计创作，主要内容包括：本发明涉及一种高阻隔抗菌PBAT聚合物及其制备方法和应用,制备方法为：首先由甘露醇与精氨酸反应制得高阻隔功能单体,然后由己二酸、丁二醇和高阻隔功能单体反应制得高阻隔抗菌预聚物,接着由高阻隔抗菌预聚物与己二酸丁二醇酯化物反应制得高阻隔抗菌低聚物,最后由对苯二甲酸丁二醇酯化物与高阻隔抗菌低聚物反应制得高阻隔抗菌PBAT聚合物；制得的高阻隔抗菌PBAT聚合物抗菌性能优良,对大肠杆菌的抑菌率为85～100％,对金黄色葡萄球菌的抑菌率为70～100％；应用为：将高阻隔抗菌PBAT聚合物进行吹塑成型或者流延成型,得到抗菌PBAT阻隔膜,抗菌PBAT阻隔膜的阻隔性能优良。本发明的方法简单,制得的抗菌PBAT阻隔膜可应用于有抗菌和阻隔需求的包装、膜类、片材制品等领域。(The invention relates to a high-barrier antibacterial PBAT polymer, a preparation method and application thereof, wherein the preparation method comprises the following steps: firstly, mannitol and arginine react to prepare a high-barrier functional monomer, then adipic acid, butanediol and the high-barrier functional monomer react to prepare a high-barrier antibacterial prepolymer, then the high-barrier antibacterial prepolymer reacts with butanediol adipate compound to prepare a high-barrier antibacterial oligomer, and finally butanediol terephthalate ester compound reacts with the high-barrier antibacterial oligomer to prepare a high-barrier antibacterial PBAT polymer; the prepared high-barrier antibacterial PBAT polymer has excellent antibacterial performance, the bacteriostasis rate to escherichia coli is 85-100%, and the bacteriostasis rate to staphylococcus aureus is 70-100%; the application is as follows: and performing blow molding or tape casting on the high-barrier antibacterial PBAT polymer to obtain the antibacterial PBAT barrier film with excellent barrier property. The method is simple, and the prepared antibacterial PBAT barrier film can be applied to the fields of packaging, films, sheet products and the like with antibacterial and barrier requirements.)

1. A high-barrier antibacterial PBAT polymer is characterized in that the molecular structural formula is as follows:

wherein the structural formula of- (O-X-O) is as follows:

wherein represents the point of attachment of the branch to the nitrogen atom; x represents the polymerization degree of a polybutylene adipate chain segment, and the value range is 500-900; y represents the polymerization degree of the polybutylene terephthalate chain segment, and the value range is 550-900.

2. The high-barrier antibacterial PBAT polymer according to claim 1, characterized in that the weight average molecular weight of the high-barrier antibacterial PBAT polymer is 220000-350000; the melt index is 2-5 g/10min measured under the conditions that the temperature is 190 ℃ and the load is 2.16 kg; the melting point is 125-145 ℃; the carboxyl end group content is 15-35 mmol/kg; the antibacterial rate to escherichia coli is 85-100%, and the antibacterial rate to staphylococcus aureus is 70-100%; the biodegradation rate in 45 days is 18.5-23.5%.

3. The method for preparing the high-barrier antibacterial PBAT polymer as claimed in claim 1 or 2, characterized in that firstly, mannitol and arginine are reacted to prepare a high-barrier functional monomer, then adipic acid, butanediol and the high-barrier functional monomer are reacted to prepare a high-barrier antibacterial prepolymer, then the high-barrier antibacterial prepolymer and butanediol adipate are reacted to prepare a high-barrier antibacterial oligomer, and finally butanediol terephthalate and the high-barrier antibacterial oligomer are reacted to prepare the high-barrier antibacterial PBAT polymer.

4. The method according to claim 3, characterized by the following specific steps:

(1) preparing a high-barrier functional monomer;

mixing mannitol and arginine, heating to 60-70 ℃, preserving heat, adding a catalyst and a coordination agent when a reaction system is in a uniform molten state, continuing heating to 75-80 ℃, and continuously reacting for 35-45 min under the atmosphere of nitrogen or inert gas to obtain a high-barrier functional monomer;

(2) preparing a high-barrier antibacterial prepolymer;

mixing adipic acid, butanediol and the high-barrier function monomer obtained in the step (1), heating to 160-170 ℃, and continuously reacting for 1-2 hours in a nitrogen or inert gas atmosphere to obtain a high-barrier antibacterial prepolymer;

(3) preparing butanediol adipate esterified substance;

mixing adipic acid and butanediol, heating to 130-140 ℃, preserving heat, continuing to heat to 170-180 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2-2.5 hours in a nitrogen or inert gas atmosphere to obtain a butanediol adipate compound;

(4) preparing butanediol terephthalate ester;

mixing terephthalic acid, butanediol and tetrabutyl titanate, heating to 180-190 ℃, keeping the temperature, continuing to heat to 210-240 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 3-4 hours in a nitrogen or inert gas atmosphere to obtain a butylene terephthalate compound;

(5) preparing a high-barrier antibacterial oligomer;

mixing the high-barrier antibacterial prepolymer obtained in the step (2), butanediol adipate obtained in the step (3), ethylene glycol antimony and trimethyl phosphate, heating to 220-230 ℃, keeping the temperature, continuing to heat to 250-260 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 2-3 hours in a nitrogen or inert gas atmosphere to obtain a high-barrier antibacterial oligomer;

(6) preparing a high-barrier antibacterial PBAT polymer;

and (3) mixing the butylene terephthalate esterified product obtained in the step (4) with the high-barrier antibacterial oligomer obtained in the step (5), heating to 230-240 ℃, keeping the temperature, continuing to heat to 260-280 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2-2.5 hours in the atmosphere of nitrogen or inert gas to obtain the high-barrier antibacterial PBAT polymer.

5. The method according to claim 4, wherein in step (1), arginine is D-arginine, L-arginine or DL-arginine; the catalyst is cuprous iodide, copper acetylacetonate, cuprous bromide or cuprous chloride; the complexing agent is 2, 2-bipyridyl; the mol ratio of mannitol to arginine is 1: 6-6.5; the mass of the catalyst is 0.03-0.06 wt% of that of the mannitol; the mass of the complexing agent is 0.02-0.05 wt% of the mass of the mannitol.

6. The method according to claim 4, wherein in the step (2), the molar ratio of the high-barrier functional monomer to the adipic acid is 1: 6-6.5; the molar ratio of the adipic acid to the butanediol is 1: 1.15-2.15.

7. The method according to claim 4, wherein in the step (3), the molar ratio of the adipic acid to the butanediol is 1: 1.1-1.3; in the step (4), the molar ratio of terephthalic acid to butanediol is 1: 2.4-2.6; the mass of tetrabutyl titanate is 0.004-0.02 wt% of that of terephthalic acid.

8. The method according to claim 4, wherein in the step (5), the molar ratio of the high-barrier antibacterial prepolymer to the butanediol adipate esterified substance is 1: 350-450; the mass of the ethylene glycol antimony is 0.001-0.01 wt% of that of the butanediol adipate ester; the mass of the trimethyl phosphate is 0.01-0.04 wt% of that of the butanediol adipate ester; in the step (6), the molar ratio of the high-barrier antibacterial oligomer to the butanediol terephthalate is 1: 350-450.

9. The application of the high-barrier antibacterial PBAT polymer according to claim 1 or 2, wherein the high-barrier antibacterial PBAT polymer is subjected to blow molding or tape casting to obtain the antibacterial PBAT barrier film.

10. The application of the method as claimed in claim 9, wherein in the blow molding, the blow molding temperature is 160-180 ℃, the blow-up ratio is 3-6: 1, and the die gap of a film blowing machine is 0.65-2.5 mm; when tape casting is carried out, the tape casting temperature is 150-190 ℃, and the width of a die lip of a tape casting die head is 0.5-2 mm; the thickness of the antibacterial PBAT barrier film is 5-50 μm,oxygen transmission rate<10cc/m²Day/0.1MPa, water vapor transmission rate<300g/m²/day。

Technical Field

The invention belongs to the technical field of PBAT polymers, and relates to a high-barrier antibacterial PBAT polymer, and a preparation method and application thereof.

Background

Poly (butylene adipate terephthalate) (PBAT) is a type of biodegradable plastic which is widely applied in the current market and is characterized by being completely degraded into H under certain conditions₂O and CO₂And no environmental pollution is caused. PBAT belongs to aliphatic-aromatic copolyester, has the characteristics of PBA and PBT, has good mechanical property and excellent biodegradability, and is one of ideal substitutes of disposable non-degradable plastics.

PBAT is commonly used in the fields of agricultural mulching films, food packages, shopping bags and the like at present, on one hand, the PBAT has higher requirements on the barrier property in the fields, but the barrier property of the PBAT on oxygen and water vapor is poorer in the film produced by taking the PBAT as the raw material due to the components and the structural characteristics of the PBAT material, the PBAT cannot meet the use requirements on liquid packages and agricultural mulching film products, and the PBAT can cause the problems of excessive water loss of plants, food deterioration and the like.

At present, researchers mainly add water-blocking agents or inorganic materials and the like into the PBAT in a physical blending mode to form a tightly interwoven network structure, so that the internal free volume in a PBAT material system is filled to a certain extent, and the PBAT with excellent water vapor blocking performance is obtained.

Patent CN 202011248988.5 discloses a full-biodegradable high-barrier PLA/PBAT composite packaging film, wherein the modified nano-silica contains C ═ C double bonds in the molecular structure, and can polymerize with modified graphene in the extrusion granulation process, thereby greatly improving the oxygen barrier performance of the PLA/PBAT composite material; the tightly interwoven network structure formed by the modified nano silicon dioxide and the modified graphene and the molecular chain of the polylactic acid are mutually permeated and twisted together through the action of hydrogen bonds, so that the water vapor blocking performance of the PLA/PBAT composite material is further improved.

The patent CN 201710624712.4 discloses a water vapor barrier PBAT full-biodegradable resin composition and a preparation method of a film, the water vapor barrier PBAT full-biodegradable film comprises 60-99 parts of PBAT, 0.5-10 parts of a degradable water blocking agent, 0.5-20 parts of organic modified montmorillonite, 0-10 parts of an organic additive and 0-10 parts of an inorganic additive, wherein the water blocking agent is a composite addition of an animal and plant composite water blocking agent, and the water vapor transmission rate of the film is less than 700g/m under the condition of 6 microns thickness²The film and the water-blocking agent can be completely degraded in natural environment, and can be widely applied to the aspects of agricultural mulching films, packaging bags, express bags, heat shrinkable films, adhesive tapes and the like.

Patent CN 201610578884.8 discloses a PBAT-based biodegradable composite material with high water vapor barrier property, the components of the composite material include PBAT, organic modified material, inorganic modified material, initiator, compatilizer and catalyst, which is to bridge PBAT and inorganic material, greatly improving the compatibility and dispersibility of inorganic material in PBAT; the inorganic material is partially in layered oriented arrangement due to the bridging effect generated by the combination of the compatilizer and the initiator in a blending system, the water molecule passing path is prolonged, and the movement time of the water molecules in the material is increased, so that the water retention of the material is obviously improved, and the water vapor transmission rate of the 10 mu m film material is 2800g/m of that of the film with the original specification²24h, reduction to 320g/m²24h, which is obviously superior to the similar materials.

The related patents reported above all select some water-blocking agents, inorganic materials, etc. to perform screw melt blending extrusion granulation with PBAT, thereby preparing the high-barrier PBAT material. The composite material obtained by physical blending usually has the defect of incomplete blocking effect caused by uneven mixing, and meanwhile, the process can be realized only by secondary processing, so that the actual production cost is increased.

When the PBAT is applied to the packaging field, the antibacterial property of the PBAT material is most concerned besides the higher requirement on the barrier property, and the quality of the antibacterial property greatly influences the quality guarantee period of the packaged product.

Therefore, the biodegradable PBAT composite material with excellent antibacterial performance and high barrier property is prepared, and has very important significance when being applied to the fields of packaging, films, sheet products and the like with antibacterial and barrier requirements.

Disclosure of Invention

In view of the above, the invention provides a high-barrier antibacterial PBAT polymer, a preparation method and an application thereof, wherein the PBAT polymer takes mannitol as a core, and introduces a high-barrier functional monomer on a PBAT main chain in a copolymerization modification mode, so that the PBAT has good antibacterial performance and barrier performance, thereby being more suitable for market demands.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a high-barrier antibacterial PBAT polymer has the following molecular structural formula:

wherein the structural formula of- (O-X-O) is as follows:

wherein represents the point of attachment of the branch to the nitrogen atom; x represents the polymerization degree of a polybutylene adipate chain segment, and the value range is 500-900; y represents the polymerization degree of the polybutylene terephthalate chain segment, and the value range is 550-900. x and y are higher than 900, which can cause significant increase of production energy consumption and cost, and is not beneficial to practical market application; the polymer with the performance lower than 500 is poor, easy to degrade and short in service life.

As a preferred technical scheme:

the high-barrier antibacterial PBAT polymer has the weight-average molecular weight of 220000-350000; the melt index is 2-5 g/10min measured under the conditions that the temperature is 190 ℃ and the load is 2.16 kg; the melting point is 125-145 ℃; the carboxyl end group content is 15-35 mmol/kg; the antibacterial rate to escherichia coli is 85-100%, and the antibacterial rate to staphylococcus aureus is 70-100%; the biodegradation rate in 45 days is 18.5-23.5%.

The invention also provides a method for preparing the high-barrier antibacterial PBAT polymer, which comprises the steps of firstly preparing a high-barrier functional monomer by the reaction of mannitol and arginine, then preparing a high-barrier antibacterial prepolymer by the reaction of adipic acid, butanediol and the high-barrier functional monomer, then preparing a high-barrier antibacterial oligomer by the reaction of the high-barrier antibacterial prepolymer and butanediol adipate esterification, and finally preparing the high-barrier antibacterial PBAT polymer by the reaction of the butanediol terephthalate esterification product and the high-barrier antibacterial oligomer.

As a preferred technical scheme:

the method comprises the following specific steps:

(1) preparing a high-barrier functional monomer;

mixing mannitol and arginine, heating to 60-70 ℃, preserving heat, adding a catalyst and a coordination agent when a reaction system is in a uniform molten state, continuing heating to 75-80 ℃, and continuously reacting for 35-45 min under the atmosphere of nitrogen or inert gas to obtain a high-barrier functional monomer; because the comb-shaped structure with six special branch chains of mannitol can show excellent barrier performance only when a high-molecular chain segment is linked, mannitol is introduced into a PBAT molecular chain to prepare high-barrier PBAT, and arginine is introduced into the branch chains of mannitol to improve the antibacterial performance of PBAT;

(2) preparing a high-barrier antibacterial prepolymer;

mixing Adipic Acid (AA), Butanediol (BDO) and the high-barrier functional monomer obtained in the step (1), heating to 160-170 ℃, and continuously reacting for 1-2 hours in the atmosphere of nitrogen or inert gas to obtain a high-barrier antibacterial prepolymer;

the esterification reaction of AA and BDO is a common intermediate reaction step in the synthesis process of PBAT, aims to obtain butanediol adipate, is convenient for subsequent polycondensation reaction, and mixes and reacts AA and BDO with a high-barrier function monomer, aims to introduce the butanediol adipate on four branched chains of the high-barrier function monomer, and then carries out polycondensation reaction to obtain the comb-shaped PBAT;

(3) preparing butanediol adipate esterified substance;

mixing adipic acid and butanediol, heating to 130-140 ℃, preserving heat, continuing to heat to 170-180 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2-2.5 hours in a nitrogen or inert gas atmosphere to obtain a butanediol adipate compound;

(4) preparing butanediol terephthalate ester;

mixing terephthalic acid (PTA), butanediol and tetrabutyl titanate (TBOT), heating to 180-190 ℃, keeping the temperature, continuing to heat to 210-240 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 3-4 hours in a nitrogen or inert gas atmosphere to obtain a butylene terephthalate compound;

(5) preparing a high-barrier antibacterial oligomer;

mixing the high-barrier antibacterial prepolymer obtained in the step (2), butanediol adipate esterified in the step (3), ethylene glycol antimony and trimethyl phosphate, heating to 220-230 ℃, keeping the temperature (esterification reaction occurs in the process), continuing heating to 250-260 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2-3 hours in the atmosphere of nitrogen or inert gas (polycondensation reaction occurs in the process) to obtain a high-barrier antibacterial oligomer;

(6) preparing a high-barrier antibacterial PBAT polymer;

and (3) mixing the butylene terephthalate esterified product obtained in the step (4) with the high-barrier antibacterial oligomer obtained in the step (5), heating to 230-240 ℃, keeping the temperature (esterification reaction occurs in the process), continuing heating to 260-280 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2-2.5 hours in the atmosphere of nitrogen or inert gas (polycondensation reaction occurs in the process) to obtain the high-barrier antibacterial PBAT polymer.

The method as described above, wherein in the step (1), arginine is D-arginine, L-arginine or DL-arginine; the catalyst is cuprous iodide, copper acetylacetonate, cuprous bromide or cuprous chloride; the complexing agent is 2, 2-bipyridyl; the mol ratio of mannitol to arginine is 1: 6-6.5; the mass of the catalyst is 0.03-0.06 wt% of that of the mannitol; the mass of the complexing agent is 0.02-0.05 wt% of the mass of the mannitol.

According to the method, in the step (2), the molar ratio of the high-barrier functional monomer to the adipic acid is 1: 6-6.5; the molar ratio of the adipic acid to the butanediol is 1: 1.15-2.15.

The method comprises the following steps of (3) enabling the molar ratio of adipic acid to butanediol to be 1: 1.1-1.3; in the step (4), the molar ratio of terephthalic acid to butanediol is 1: 2.4-2.6; the mass of tetrabutyl titanate is 0.004-0.02 wt% of that of terephthalic acid.

According to the method, in the step (5), the molar ratio of the high-barrier antibacterial prepolymer to the butanediol adipate esterified substance is 1: 350-450; the mass of the ethylene glycol antimony is 0.001-0.01 wt% of that of the butanediol adipate ester; the mass of the trimethyl phosphate is 0.01-0.04 wt% of that of the butanediol adipate ester; in the step (6), the molar ratio of the high-barrier antibacterial oligomer to the butanediol terephthalate is 1: 350-450.

The invention also provides application of the high-barrier antibacterial PBAT polymer, and the high-barrier antibacterial PBAT polymer is subjected to blow molding or tape casting to obtain the antibacterial PBAT barrier film.

As a preferred technical scheme:

according to the application, during blow molding, the blow molding temperature is 160-180 ℃, the blow-up ratio is 3-6: 1, and the die gap of a film blowing machine is 0.65-2.5 mm; when tape casting is carried out, the tape casting temperature is 150-190 ℃, and the width of a die lip of a tape casting die head is 0.5-2 mm; the thickness of the antibacterial PBAT barrier film is 5-50 mu m, and the oxygen transmission rate<10cc/m²Day/0.1MPa, water vapor transmission rate<300g/m²And/day. The pure PBAT film prepared according to the same technical scheme has the oxygen transmission rate of 510cc/m²Day/0.1MPa, water vapor transmission rate of 810g/m²And day proves that the antibacterial PBAT barrier film provided by the invention has excellent water vapor barrier property.

The principle of the invention is as follows:

the high-barrier antibacterial PBAT polymer prepared by the invention is a comb-shaped polymer, and the special high-density branched chain of the comb-shaped polymer ensures that the structure of the polymer is compact, and a compact tissue can be formed based on the order of high molecules so as to prevent oxygen and water vapor from entering, so that the high-barrier antibacterial PBAT polymer has excellent barrier property and can meet the barrier requirements of the market on packaging, mulching films and the like. In addition, the molecular structure of the high-barrier antibacterial PBAT polymer contains a group formed by arginine, wherein the arginine has a guanidyl functional group, and the guanidyl has high activity and positive charge, so the high-barrier antibacterial PBAT polymer is easily adsorbed on the surface of a negatively charged microorganism, can block the action of cell lysozyme, can denature and destroy the surface layer structure of a cell, and can inhibit the propagation of bacteria to achieve the antibacterial purpose.

At present, most of synthesized PBAT in the prior art are linear structures, the PBAT with specific structure and performance is synthesized by designing a molecular structure, specifically, the PBAT which is prepared by using mannitol as a core, reacting with arginine, then polycondensing butanediol adipate and finally terminating with butanediol terephthalate has high barrier, antibacterial and biodegradable properties.

Firstly, mannitol with an ordered one-dimensional linear structure is used as a central core of the comb polymer, and arginine and hydroxyl functional groups of the mannitol are subjected to esterification reaction to synthesize a comb structure with excellent antibacterial performance; because the mannitol has a branched chain structure and a plurality of active hydroxyl structures, the modified barrier monomer has a plurality of reactive active sites, and therefore, the molecular chain growth process in the polymerization process (namely, the reaction in the step (5) and the step (6)) is facilitated.

Meanwhile, arginine with an antibacterial structure is introduced to endow the PBAT with antibacterial and barrier properties, particularly, in the field of biodegradable film materials, PBAT with a branched chain structure has a micro-crosslinking structure, but conventional micro-crosslinking causes no biodegradation, and the branched chain molecular structure design of mannitol realizes the micro-crosslinking effect, the biodegradation property and the antibacterial property.

In addition, the comb-shaped structure contains a plurality of terminal groups, so that the reaction activity is high, the ester exchange is promoted, the reaction is faster compared with the synthesis process of general linear PBAT, and the rapid growth of a molecular chain is facilitated.

The invention adopts the sequence of firstly polycondensing butanediol adipate and then polycondensing butanediol terephthalate in the synthesis process, and the reason is that: firstly, the butanediol adipate is connected with arginine, and the butanediol adipate is not easy to be attacked and decomposed by microorganisms due to the antibacterial property of the arginine, so that the service life of the polymer is prolonged, and the stability of the polymer in the processing and using processes is improved; secondly, the butylene terephthalate is not easy to biodegrade, and is used as the outermost end of the comb-shaped polymer branched chain, so that the antibacterial property of the polymer is more stable and long-acting, and in addition, the rigidity of the polymer can be enhanced, and more excellent mechanical property can be obtained.

Has the advantages that:

(1) according to the preparation method of the high-barrier antibacterial PBAT polymer, mannitol is used as a core, and a high-barrier functional monomer is introduced into a PBAT main chain in a copolymerization modification mode, so that the PBAT has good antibacterial performance and barrier performance, and the market demand is met;

(2) the high-barrier antibacterial PBAT polymer is a comb-shaped polymer, and the special high-density branched chain of the comb-shaped polymer enables the structure of the polymer to be compact, and a compact tissue can be formed based on high molecular order so as to prevent oxygen and water vapor from entering, so that the high-barrier antibacterial PBAT polymer has excellent barrier property; in addition, the polymer also contains a group formed by arginine, so that the aim of inhibiting bacterial reproduction and achieving antibiosis is fulfilled;

(3) the high-barrier antibacterial PBAT polymer provided by the invention has good antibacterial performance and barrier performance, can meet the barrier requirements of the market on packaging, mulching films and the like, and is wide in application range.

Drawings

FIG. 1 is a chemical reaction formula for preparing a high barrier function monomer according to the present invention;

FIG. 2 is a chemical reaction formula of preparing a high barrier antibacterial prepolymer according to the present invention;

FIG. 3 is a chemical reaction formula for preparing butanediol adipate compound according to the invention;

FIG. 4 shows the chemical reaction scheme for preparing butylene terephthalate according to the present invention;

FIG. 5 shows the chemical reaction formula for preparing the high-barrier antibacterial oligomer according to the present invention;

FIG. 6 is a chemical reaction formula for preparing a high-barrier antibacterial PBAT polymer according to the present invention;

FIG. 7 is a hydrogen nuclear magnetic resonance spectrum of a high-barrier functional monomer prepared by the invention;

FIG. 8 is a hydrogen nuclear magnetic resonance spectrum of a blocking antibacterial prepolymer prepared by the present invention;

FIG. 9 is a hydrogen nuclear magnetic resonance spectrum of a high-barrier antibacterial oligomer prepared by the present invention;

FIG. 10 is the hydrogen nuclear magnetic resonance spectrum of the high-barrier antibacterial PBAT polymer prepared by the invention.

Detailed Description

The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

In the following examples, some parameters were tested as follows:

the molecular weight was determined by Gel Permeation Chromatography (GPC).

The melt index was measured using a melt flow rate meter at a temperature of 190 ℃ under a load of 2.16 kg.

The melting point is measured by a differential calorimeter (DSC), nitrogen is used as protective gas, the gas flow is 50mL/min, the temperature is increased at the speed of 10 ℃/min, and the maximum melting peak value in the temperature increasing process is the melting point.

The content of terminal carboxyl groups was measured by a photometric method in titrimetric analysis of terminal carboxyl group content in polyester (FZ/T54012-2006).

The bacteriostatic rate of escherichia coli and staphylococcus aureus is measured according to the antibacterial plastic-antibacterial performance test method and antibacterial effect (QB/T2591-2003).

Biodegradation Rate for 45 days the method for determining the carbon dioxide released was used according to "determination of the ultimate aerobic biological decomposition Capacity of Material under controlled composting conditions part 1: the measurement was carried out by the general method (GB/T19277.1-2011).

The oxygen permeability was measured according to the differential pressure test method for gas permeability of Plastic films and sheets (GB/T1038-2000).

The water vapor transmission rate was measured according to the cup method (GB/T1037-1988) which is a test method for water vapor permeability of plastic films and sheets.

Example 1

A preparation method of a high-barrier antibacterial PBAT polymer comprises the following specific steps:

(1) preparing a high-barrier functional monomer;

mixing mannitol and D-arginine in a molar ratio of 1:6.4, heating to 60 ℃, keeping the temperature, adding cuprous iodide and 2, 2-bipyridyl when a reaction system is in a uniform molten state, continuing heating to 75 ℃, and continuously reacting for 38min in a nitrogen atmosphere to obtain a high-barrier functional monomer, wherein the chemical reaction formula is shown in figure 1; the mass of cuprous iodide is 0.03 wt% of that of mannitol; the mass of the 2, 2-bipyridyl is 0.03 wt% of that of the mannitol;

the hydrogen nuclear magnetic resonance spectrum of the high-barrier functional monomer is shown in fig. 7, wherein corresponding nuclear magnetic chemical shifts of each hydrogen atom, b, c and h correspond to characteristic absorption peaks of guanidino in arginine, d, e and f are characteristic absorption peaks of mannitol, and characteristic absorption peaks of carboxyl and hydroxyl do not appear, which indicates that the mannitol and the arginine have undergone ester exchange reaction to synthesize the high-barrier functional monomer;

(2) preparing a high-barrier antibacterial prepolymer;

mixing adipic acid, butanediol and the high-barrier functional monomer obtained in the step (1), heating to 160 ℃, and continuously reacting for 1h in a nitrogen atmosphere to obtain a high-barrier antibacterial prepolymer, wherein the chemical reaction formula is shown in figure 2; wherein the molar ratio of the high-barrier functional monomer to the adipic acid is 1: 6.3; the molar ratio of adipic acid to butanediol is 1: 1.35;

the hydrogen nuclear magnetic resonance spectrum of the high-barrier antibacterial prepolymer is shown in fig. 8, wherein corresponding nuclear magnetic chemical shifts of hydrogen atoms, b, j and l correspond to characteristic absorption peaks of guanidino in arginine, g is a characteristic absorption peak of methylene generated by reaction of AA and BDO and connected by ester bonds, and no characteristic absorption peak of carboxyl appears, which indicates that the prepared structure is consistent with the designed structure;

(3) preparing butanediol adipate esterified substance;

mixing adipic acid and butanediol with a molar ratio of 1:1.1, heating to 130 ℃, keeping the temperature, continuing to heat to 170 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2 hours in a nitrogen atmosphere to obtain a butanediol adipate compound, wherein the chemical reaction formula is shown in figure 3;

(4) preparing butanediol terephthalate ester;

mixing terephthalic acid, butanediol and tetrabutyl titanate, heating to 190 ℃, keeping the temperature, continuing to heat to 240 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 3 hours in a nitrogen atmosphere to obtain a butylene terephthalate compound, wherein the chemical reaction formula is shown in figure 4; the molar ratio of terephthalic acid to butanediol is 1: 2.4; the mass of tetrabutyl titanate is 0.013 wt% of the mass of terephthalic acid;

(5) preparing a high-barrier antibacterial oligomer;

mixing the high-barrier antibacterial prepolymer obtained in the step (2), the butanediol adipate esterified substance obtained in the step (3), ethylene glycol antimony and trimethyl phosphate, heating to 220 ℃, keeping the temperature, continuing to heat to 253 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 2.5 hours in a nitrogen atmosphere to obtain a high-barrier antibacterial oligomer, wherein the chemical reaction formula is shown in FIG. 5; the molar ratio of the high-barrier antibacterial prepolymer to the butanediol adipate esterified substance is 1: 350; the mass of the ethylene glycol antimony is 0.008 wt% of that of the butanediol adipate ester; the mass of the trimethyl phosphate is 0.01 wt% of that of the butanediol adipate ester;

a hydrogen nuclear magnetic resonance spectrum of the high-barrier antibacterial oligomer is shown in fig. 9, wherein corresponding nuclear magnetic chemical shifts of each hydrogen atom, and k is a characteristic absorption peak of methylene which is generated by condensation polymerization of butanediol adipate and is connected with an ester bond, which indicates that the structure of the prepared high-barrier antibacterial oligomer is consistent with the prediction;

(6) preparing a high-barrier antibacterial PBAT polymer;

mixing the butylene terephthalate esterified substance obtained in the step (4) with the high-barrier antibacterial oligomer obtained in the step (5), heating to 230 ℃, keeping the temperature, continuing to heat to 260 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2.3 hours in a nitrogen atmosphere to obtain a high-barrier antibacterial PBAT polymer, wherein the chemical reaction formula is shown in FIG. 6; wherein the molar ratio of the high-barrier antibacterial oligomer to the butanediol terephthalate is 1: 350;

the hydrogen nuclear magnetic resonance spectrum of the high-barrier antibacterial PBAT polymer is shown in figure 10, wherein the corresponding nuclear magnetic chemical shifts of each hydrogen atom, b is the characteristic absorption peak of a benzene ring in PTA, and h is the characteristic absorption peak of methylene which is generated by polycondensation of butylene terephthalate compounds and is connected with ester bonds, thereby proving that the high-barrier antibacterial PBAT polymer is successfully prepared.

The molecular structural formula of the prepared high-barrier antibacterial PBAT polymer is as follows:

wherein the structural formula of- (O-X-O) is as follows:

wherein represents the point of attachment of the branch to the nitrogen atom; x represents the degree of polymerization of a polybutylene adipate chain segment; y represents the degree of polymerization of the polybutylene terephthalate segment; the weight average molecular weight of the high-barrier antibacterial PBAT polymer is 2.4 multiplied by 10⁵(ii) a The melt index was 3 as measured at a temperature of 190 ℃ under a load of 2.16 kg.2g/10 min; the melting point is 134 ℃; the carboxyl end group content is 19 mmol/kg; the bacteriostasis rate to escherichia coli is 91%, and the bacteriostasis rate to staphylococcus aureus is 87%; the biodegradation rate in 45 days was 20.1%.

And carrying out tape casting on the high-barrier antibacterial PBAT polymer to obtain the antibacterial PBAT barrier film, wherein the tape casting temperature is 165 ℃ and the width of a die lip of a tape casting die head is 1.5mm during tape casting.

The obtained antibacterial PBAT barrier film has a thickness of 5 μm and an oxygen transmission rate of 7.2cc/m²Day/0.1MPa, water vapor transmission rate of 125g/m²/day。

Example 2

A preparation method of a high-barrier antibacterial PBAT polymer comprises the following specific steps:

(1) preparing a high-barrier functional monomer;

mixing mannitol and L-arginine in a molar ratio of 1:6.2, heating to 64 ℃, keeping the temperature, adding copper acetylacetonate and 2, 2-bipyridyl when a reaction system is in a uniform molten state, continuously heating to 76 ℃, and continuously reacting for 42min in a nitrogen atmosphere to obtain a high-barrier functional monomer; the mass of the copper acetylacetonate is 0.045 wt% of that of the mannitol; the mass of the 2, 2-bipyridyl is 0.038 wt% of that of the mannitol;

(2) preparing a high-barrier antibacterial prepolymer;

mixing adipic acid, butanediol and the high-barrier functional monomer obtained in the step (1), heating to 167 ℃, and continuously reacting for 1.3h in a nitrogen atmosphere to obtain a high-barrier antibacterial prepolymer; wherein the molar ratio of the high-barrier functional monomer to the adipic acid is 1: 6.2; the molar ratio of adipic acid to butanediol is 1: 1.75;

(3) preparing butanediol adipate esterified substance;

mixing adipic acid and butanediol with a molar ratio of 1:1.25, heating to 137 ℃, keeping the temperature, continuing to heat to 178 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2.4 hours in a nitrogen atmosphere to obtain a butanediol adipate compound;

(4) preparing butanediol terephthalate ester;

mixing terephthalic acid, butanediol and tetrabutyl titanate, heating to 186 ℃, keeping the temperature, continuing to heat to 225 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 3.4 hours in a nitrogen atmosphere to obtain a butylene terephthalate compound; the molar ratio of terephthalic acid to butanediol is 1: 2.55; the mass of tetrabutyl titanate is 0.012 wt% of the mass of terephthalic acid;

(5) preparing a high-barrier antibacterial oligomer;

mixing the high-barrier antibacterial prepolymer obtained in the step (2), butanediol adipate obtained in the step (3), ethylene glycol antimony and trimethyl phosphate, heating to 226 ℃, keeping the temperature, continuously heating to 254 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 2.5 hours in a nitrogen atmosphere to obtain a high-barrier antibacterial oligomer; the molar ratio of the high-barrier antibacterial prepolymer to the butanediol adipate esterified substance is 1: 365; the mass of the ethylene glycol antimony is 0.008 wt% of that of the butanediol adipate ester; the mass of the trimethyl phosphate is 0.025wt percent of that of the butanediol adipate;

(6) preparing a high-barrier antibacterial PBAT polymer;

mixing the butylene terephthalate esterified substance obtained in the step (4) with the high-barrier antibacterial oligomer obtained in the step (5), heating to 235 ℃, keeping the temperature, continuing to heat to 266 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2.4 hours in a nitrogen atmosphere to obtain a high-barrier antibacterial PBAT polymer; wherein the molar ratio of the high-barrier antibacterial oligomer to the butanediol terephthalate is 1: 365.

The molecular structural formula of the prepared high-barrier antibacterial PBAT polymer is as follows:

wherein the structural formula of- (O-X-O) is as follows:

wherein represents the point of attachment of the branch to the nitrogen atom; x represents the degree of polymerization of a polybutylene adipate chain segment; y represents the degree of polymerization of the polybutylene terephthalate segment; the weight average molecular weight of the high-barrier antibacterial PBAT polymer is 2.8 multiplied by 10⁵(ii) a A melt index of 4.2g/10min measured at a temperature of 190 ℃ and a load of 2.16 kg; the melting point is 142 ℃; the carboxyl end group content is 29 mmol/kg; the bacteriostasis rate to escherichia coli is 87%, and the bacteriostasis rate to staphylococcus aureus is 75%; the biodegradation rate in 45 days was 18.9%.

And performing blow molding on the high-barrier antibacterial PBAT polymer to obtain an antibacterial PBAT barrier film, wherein the blow molding temperature is 172 ℃, the blow-up ratio is 5:1, and the die gap of a film blowing machine is 1.3 mm.

The thickness of the prepared antibacterial PBAT barrier film is 50 mu m, and the oxygen transmission rate is 8.6cc/m²Day/0.1MPa, water vapor transmission rate of 216g/m²/day。

Example 3

A preparation method of a high-barrier antibacterial PBAT polymer comprises the following specific steps:

(1) preparing a high-barrier functional monomer;

mixing mannitol and DL-arginine in a molar ratio of 1:6.5, heating to 70 ℃, keeping the temperature, adding cuprous bromide and 2, 2-bipyridyl when a reaction system is in a uniform molten state, continuing heating to 78 ℃, and continuously reacting for 42min in a nitrogen atmosphere to obtain a high-barrier functional monomer; the mass of the cuprous bromide is 0.05 wt% of that of the mannitol; the mass of the 2, 2-bipyridyl is 0.04 wt% of that of the mannitol;

(2) preparing a high-barrier antibacterial prepolymer;

mixing adipic acid, butanediol and the high-barrier function monomer obtained in the step (1), heating to 170 ℃, and continuously reacting for 2 hours in a nitrogen atmosphere to obtain a high-barrier antibacterial prepolymer; wherein the molar ratio of the high-barrier functional monomer to the adipic acid is 1: 6.5; the molar ratio of adipic acid to butanediol is 1: 2;

(3) preparing butanediol adipate esterified substance;

mixing adipic acid and butanediol with a molar ratio of 1:1.3, heating to 140 ℃, keeping the temperature, continuing to heat to 180 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 2.5 hours in a nitrogen atmosphere to obtain a butanediol adipate compound;

(4) preparing butanediol terephthalate ester;

mixing terephthalic acid, butanediol and tetrabutyl titanate, heating to 190 ℃, keeping the temperature, continuing to heat to 240 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 4 hours in a nitrogen atmosphere to obtain a butylene terephthalate compound; the molar ratio of terephthalic acid to butanediol is 1: 2.6; the mass of tetrabutyl titanate is 0.02 wt% of that of terephthalic acid;

(5) preparing a high-barrier antibacterial oligomer;

mixing the high-barrier antibacterial prepolymer obtained in the step (2), butanediol adipate obtained in the step (3), ethylene glycol antimony and trimethyl phosphate, heating to 230 ℃, keeping the temperature, continuing to heat to 260 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 3 hours in a nitrogen atmosphere to obtain a high-barrier antibacterial oligomer; the molar ratio of the high-barrier antibacterial prepolymer to the butanediol adipate esterified substance is 1: 400; the mass of the ethylene glycol antimony is 0.0065 wt% of that of the butanediol adipate; the mass of the trimethyl phosphate is 0.03 wt% of that of the butanediol adipate;

(6) preparing a high-barrier antibacterial PBAT polymer;

mixing the butylene terephthalate esterified substance obtained in the step (4) with the high-barrier antibacterial oligomer obtained in the step (5), heating to 240 ℃, keeping the temperature, continuing to heat to 270 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2.5 hours in a nitrogen atmosphere to obtain a high-barrier antibacterial PBAT polymer; wherein the molar ratio of the high-barrier antibacterial oligomer to the butanediol terephthalate is 1: 400.

The molecular structural formula of the prepared high-barrier antibacterial PBAT polymer is as follows:

wherein the structural formula of- (O-X-O) is as follows:

wherein represents the point of attachment of the branch to the nitrogen atom; x represents the degree of polymerization of a polybutylene adipate chain segment; y represents the degree of polymerization of the polybutylene terephthalate segment; the weight average molecular weight of the high-barrier antibacterial PBAT polymer is 3.1 multiplied by 10⁵(ii) a A melt index of 3.8g/10min measured at a temperature of 190 ℃ and a load of 2.16 kg; the melting point is 139 ℃; the carboxyl end group content is 22 mmol/kg; the bacteriostasis rate to escherichia coli is 96 percent, and the bacteriostasis rate to staphylococcus aureus is 91 percent; the biodegradation rate in 45 days was 22.1%.

And performing blow molding on the high-barrier antibacterial PBAT polymer to obtain an antibacterial PBAT barrier film, wherein the blow molding temperature is 180 ℃, the blow-up ratio is 6:1, and the die gap of a film blowing machine is 2.5 mm.

The thickness of the prepared antibacterial PBAT barrier film is 10 mu m, and the oxygen transmission rate is 9.3cc/m²Day/0.1MPa, water vapor transmission rate of 289g/m²/day。

Comparative example 1

A method for preparing a PBAT polymer, substantially the same as in example 3, except that comparative example 1 does not perform step (1), and the high barrier functional monomer in step (2) is replaced with DL-arginine.

The weight average molecular weight of the PBAT polymer obtained was 4.2X 10⁴(ii) a A melt index of 7.8g/10min measured at a temperature of 190 ℃ and a load of 2.16 kg; the melting point is 121 ℃; the carboxyl end group content is 10 mmol/kg; the bacteriostasis rate to escherichia coli is 79 percent, and the bacteriostasis rate to staphylococcus aureus is 65 percent; the biodegradation rate in 45 days was 23.8%.

After the PBAT polymer was processed into a film in the same manner and under the same conditions as in example 3, the film had a thickness of 10 μm and an oxygen transmission rate of 24.4cc/m²Day/0.1MPa, water vapor transmission rate of 425g/m²/day。

Comparing example 3 with comparative example 1, the PBAT polymer prepared in example 3 has more excellent barrier properties and can effectively block oxygen and water vapor, because in comparative example 1, the compactness of the structure is deteriorated and the oxygen transmission rate and the water vapor transmission rate are both increased significantly due to the fact that the polymer is not a comb-shaped structure but a general linear polymer.

Comparative example 2

A method for preparing a PBAT polymer, substantially the same as in example 3, except that comparative example 2 does not perform steps (1) and (2), and the high-barrier antibacterial prepolymer in step (5) is replaced with mannitol.

The weight average molecular weight of the PBAT polymer obtained was 2.5X 10⁵(ii) a A melt index of 4.5g/10min measured at a temperature of 190 ℃ and a load of 2.16 kg; the melting point is 126 ℃; the carboxyl end group content is 18 mmol/kg; the bacteriostasis rate to escherichia coli is 0.2 percent, and the bacteriostasis rate to staphylococcus aureus is 0 percent; the biodegradation rate in 45 days was 24.1%.

After the PBAT polymer was processed into a film in the same manner and under the same conditions as in example 3, the film had a thickness of 10 μm and an oxygen transmission rate of 7.6cc/m²Day/0.1MPa, water vapor transmission rate of 115g/m²/day。

Comparing example 3 with comparative example 2, the PBAT polymer prepared in example 3 has a high bacteriostatic ratio against e.coli and s.aureus because the PBAT polymer prepared in comparative example 2 has almost no antibacterial property because arginine is not introduced during the synthesis process.

Comparative example 3

A method for producing a PBAT polymer, which is substantially the same as in example 3, except that "the butylene adipate compound obtained in step (3)" in step (5) is replaced with "the butylene terephthalate compound obtained in step (4)" and "the butylene terephthalate compound obtained in step (4)" in step (6) is replaced with "the butylene adipate compound obtained in step (3)".

The weight average molecular weight of the PBAT polymer obtained was 6.1X 10⁴(ii) a The melt was measured at a temperature of 190 ℃ and a load of 2.16kgThe melt index is 3.9g/10 min; the melting point is 134 ℃; the carboxyl end group content is 23 mmol/kg; the bacteriostasis rate to escherichia coli is 72 percent, and the bacteriostasis rate to staphylococcus aureus is 63 percent; the biodegradation rate in 45 days was 25.1%.

After the PBAT polymer was processed into a film in the same manner and under the same conditions as in example 3, the film had a thickness of 10 μm and an oxygen transmission rate of 13.2cc/m²Day/0.1MPa, water vapor transmission rate of 378g/m²/day。

Comparing example 3 with comparative example 3, the molecular weight of the PBAT polymer prepared in comparative example 3 is significantly reduced because it is difficult to further polycondense the butanediol adipate esterified after the polycondensation reaction with the butanediol terephthalate. In addition, the antibacterial performance is also affected by the antibacterial agent, and the antibacterial rate is remarkably reduced.

Comparative example 4

A preparation method of PBAT polymer comprises the following specific steps:

(1) preparing butanediol adipate esterified substance;

mixing adipic acid and butanediol with a molar ratio of 1:1.2, heating to 135 ℃, keeping the temperature, continuing to heat to 176 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2 hours in a nitrogen atmosphere to obtain a butanediol adipate compound;

(2) preparing butanediol terephthalate ester;

mixing terephthalic acid, butanediol and tetrabutyl titanate, heating to 187 ℃, keeping the temperature, continuing to heat to 216 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 3 hours in a nitrogen atmosphere to obtain a butylene terephthalate compound; the molar ratio of terephthalic acid to butanediol is 1: 2.5; the mass of tetrabutyl titanate is 0.009 wt% of that of terephthalic acid;

(3) preparing PBAT;

mixing the butanediol adipate esterified substance obtained in the step (1), the butanediol terephthalate esterified substance obtained in the step (2), ethylene glycol antimony and trimethyl phosphate, heating to 228 ℃, keeping the temperature, continuing to heat to 258 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 2.3 hours in a nitrogen atmosphere to obtain PBAT; wherein the molar ratio of the butanediol adipate esterified substance to the butanediol terephthalate esterified substance is 1: 1.4; the mass of the ethylene glycol antimony is 0.009 wt% of that of the butanediol adipate; the mass of the trimethyl phosphate is 0.023 wt% of the mass of the butanediol adipate;

(4) preparing an antibacterial PBAT polymer;

drying the PBAT obtained in the step (3) and arginine in a vacuum drying oven, fully mixing, pouring into a single-screw extruder for blending, and cooling at room temperature to obtain a blend, namely the antibacterial PBAT polymer; wherein the molar ratio of arginine to PBAT is 1: 38; the temperature of the vacuum drying oven is 90 ℃, and the drying time is 4 hours; the blending temperature is 170 ℃ and the rotating speed is 32 r/min.

The weight average molecular weight of the PBAT polymer obtained was 3.8X 10⁴(ii) a A melt index of 6.9g/10min measured at a temperature of 190 ℃ and a load of 2.16 kg; the melting point is 117 ℃; the carboxyl end group content is 9 mmol/kg; the bacteriostasis rate to escherichia coli is 55 percent, and the bacteriostasis rate to staphylococcus aureus is 43 percent; the biodegradation rate in 45 days was 28.9%.

After the PBAT polymer was processed into a film in the same manner and under the same conditions as in example 3, the film had a thickness of 10 μm and an oxygen transmission rate of 30.3cc/m²Day/0.1MPa, water vapor transmission rate of 518g/m²/day。

Comparing example 3 with comparative example 4, the barrier property of the PBAT polymer prepared in comparative example 4 is poor, the antibacterial index is also significantly poor, which indicates that arginine directly introduced in a blending manner is easy to migrate.

Comparative example 5

A preparation method of PBAT polymer comprises the following specific steps:

(1) preparing a high-barrier functional monomer;

mixing mannitol and arginine with a molar ratio of 1:6.3, heating to 67 ℃, keeping the temperature, adding cuprous bromide and 2, 2-bipyridyl when a reaction system is in a uniform molten state, continuing heating to 78 ℃, and continuously reacting for 39min in a nitrogen atmosphere to obtain a high-barrier functional monomer; the mass of the cuprous bromide is 0.035 wt% of that of the mannitol; the mass of the 2, 2-bipyridyl is 0.029 wt% of that of the mannitol;

(2) preparing butanediol adipate esterified substance;

mixing adipic acid and butanediol with a molar ratio of 1:1.3, heating to 140 ℃, keeping the temperature, continuing to heat to 180 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 2.5 hours in a nitrogen atmosphere to obtain a butanediol adipate compound;

(3) preparing butanediol terephthalate ester;

mixing terephthalic acid, butanediol and tetrabutyl titanate, heating to 190 ℃, keeping the temperature, continuing to heat to 210 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 3.8 hours in a nitrogen atmosphere to obtain a butylene terephthalate compound; the molar ratio of terephthalic acid to butanediol is 1: 2.6; the mass of tetrabutyl titanate is 0.02 wt% of that of terephthalic acid;

(4) preparing PBAT;

mixing the butanediol adipate esterified substance obtained in the step (2), the butanediol terephthalate esterified substance obtained in the step (3), ethylene glycol antimony and trimethyl phosphate, heating to 228 ℃, keeping the temperature, continuing to heat to 255 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 2.1 hours in a nitrogen atmosphere to obtain PBAT; wherein the molar ratio of the butanediol adipate esterified substance to the butanediol terephthalate esterified substance is 1: 1.6; the mass of the ethylene glycol antimony is 0.011 wt% of that of the butanediol adipate; the mass of the trimethyl phosphate is 0.027 wt% of that of the butanediol adipate;

(5) preparing an antibacterial PBAT polymer;

drying the antibacterial monomer obtained in the step (1) and the PBAT obtained in the step (4) in a vacuum drying oven, fully mixing, pouring into a single-screw extruder for blending, and cooling at room temperature to obtain a blend, namely the antibacterial PBAT polymer; wherein the molar ratio of the antibacterial monomer to the PBAT is 1: 35; the temperature of the vacuum drying oven is 90 ℃, and the drying time is 4 hours; the blending temperature is 168 ℃, and the rotating speed is 32 r/min.

The weight average molecular weight of the PBAT polymer obtained was 3.2X 10⁵(ii) a The melt index was measured at a temperature of 190 ℃ under a load of 2.16kgThe number is 4.9g/10 min; the melting point is 131 ℃; the carboxyl end group content is 26 mmol/kg; the bacteriostasis rate to escherichia coli is 67%, and the bacteriostasis rate to staphylococcus aureus is 54%; the biodegradation rate in 45 days was 29.4%.

After the PBAT polymer was processed into a film in the same manner and under the same conditions as in example 3, the film had a thickness of 10 μm and an oxygen transmission rate of 10.2cc/m²Day/0.1MPa, water vapor transmission rate of 324g/m²/day。

Comparing example 3 with comparative example 5, the PBAT polymer prepared in comparative example 5 also shows the phenomenon that the high-barrier functional monomer is easy to migrate, and the biodegradation rate is high, which indicates that the durability is not good, and the market application is not facilitated.

Example 4

A preparation method of a high-barrier antibacterial PBAT polymer comprises the following specific steps:

(1) preparing a high-barrier functional monomer;

mixing mannitol and D-arginine in a molar ratio of 1:6, heating to 62 ℃, preserving heat, adding cuprous chloride and 2, 2-bipyridyl when a reaction system is in a uniform molten state, continuing heating to 77 ℃, and continuously reacting for 35min in a helium atmosphere to obtain a high-barrier functional monomer; the mass of the cuprous chloride is 0.04 wt% of that of the mannitol; the mass of the 2, 2-bipyridyl is 0.05 wt% of that of the mannitol;

(2) preparing a high-barrier antibacterial prepolymer;

mixing adipic acid, butanediol and the high-barrier function monomer obtained in the step (1), heating to 162 ℃, and continuously reacting for 1.5 hours in a helium atmosphere to obtain a high-barrier antibacterial prepolymer; wherein the molar ratio of the high-barrier functional monomer to the adipic acid is 1: 6; the molar ratio of adipic acid to butanediol is 1: 1.15;

(3) preparing butanediol adipate esterified substance;

mixing adipic acid and butanediol with a molar ratio of 1:1.2, heating to 134 ℃, keeping the temperature, continuing to heat to 172 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2.2 hours in a helium atmosphere to obtain a butanediol adipate compound;

(4) preparing butanediol terephthalate ester;

mixing terephthalic acid, butanediol and tetrabutyl titanate, heating to 180 ℃, keeping the temperature, continuing to heat to 210 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 3.3 hours in a helium atmosphere to obtain a butylene terephthalate compound; the molar ratio of terephthalic acid to butanediol is 1: 2.45; the mass of tetrabutyl titanate is 0.004 wt% of that of terephthalic acid;

(5) preparing a high-barrier antibacterial oligomer;

mixing the high-barrier antibacterial prepolymer obtained in the step (2), butanediol adipate obtained in the step (3), ethylene glycol antimony and trimethyl phosphate, heating to 222 ℃, keeping the temperature, continuing to heat to 250 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 2 hours in a helium atmosphere to obtain a high-barrier antibacterial oligomer; the molar ratio of the high-barrier antibacterial prepolymer to the butanediol adipate esterified substance is 1: 370; the mass of the ethylene glycol antimony is 0.001 wt% of that of the butanediol adipate ester; the mass of the trimethyl phosphate is 0.02 wt% of that of the butanediol adipate;

(6) preparing a high-barrier antibacterial PBAT polymer;

mixing the butylene terephthalate esterified substance obtained in the step (4) with the high-barrier antibacterial oligomer obtained in the step (5), heating to 233 ℃, keeping the temperature, continuing to heat to 280 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2 hours in a helium atmosphere to obtain a high-barrier antibacterial PBAT polymer; wherein the molar ratio of the high-barrier antibacterial oligomer to the butanediol terephthalate is 1: 355.

The molecular structural formula of the prepared high-barrier antibacterial PBAT polymer is as follows:

wherein the structural formula of- (O-X-O) is as follows:

wherein represents the point of attachment of the branch to the nitrogen atom; x represents the degree of polymerization of a polybutylene adipate chain segment; y represents the degree of polymerization of the polybutylene terephthalate segment; the weight average molecular weight of the high-barrier antibacterial PBAT polymer is 3.2 multiplied by 10⁵(ii) a A melt index of 4.1g/10min measured at a temperature of 190 ℃ and a load of 2.16 kg; the melting point is 142 ℃; the carboxyl end group content is 21 mmol/kg; the bacteriostasis rate to escherichia coli is 86%, and the bacteriostasis rate to staphylococcus aureus is 78%; the biodegradation rate in 45 days was 19.2%.

And performing blow molding on the high-barrier antibacterial PBAT polymer to obtain an antibacterial PBAT barrier film, wherein the blow molding temperature is 160 ℃, the blow-up ratio is 3:1, and the die gap of a film blowing machine is 0.65 mm.

The thickness of the prepared antibacterial PBAT barrier film is 30 mu m, and the oxygen transmission rate is 5.3cc/m²Day/0.1MPa, water vapor transmission rate 221g/m²/day。

Example 5

A preparation method of a high-barrier antibacterial PBAT polymer comprises the following specific steps:

(1) preparing a high-barrier functional monomer;

mixing mannitol and L-arginine in a molar ratio of 1:6.1, heating to 66 ℃, keeping the temperature, adding cuprous iodide and 2, 2-bipyridyl when a reaction system is in a uniform molten state, continuing heating to 79 ℃, and continuously reacting for 45min under a neon atmosphere to obtain a high-barrier functional monomer; the mass of cuprous iodide is 0.06 wt% of that of mannitol; the mass of the 2, 2-bipyridyl is 0.02 wt% of that of the mannitol;

(2) preparing a high-barrier antibacterial prepolymer;

mixing adipic acid, butanediol and the high-barrier functional monomer obtained in the step (1), heating to 164 ℃, and continuously reacting for 1.7h in a neon atmosphere to obtain a high-barrier antibacterial prepolymer; wherein the molar ratio of the high-barrier functional monomer to the adipic acid is 1: 6.1; the molar ratio of adipic acid to butanediol is 1: 2.15;

(3) preparing butanediol adipate esterified substance;

mixing adipic acid and butanediol with a molar ratio of 1:1.15, heating to 138 ℃, keeping the temperature, continuing to heat to 175 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 2.3 hours in a neon atmosphere to obtain a butanediol adipate compound;

(4) preparing butanediol terephthalate ester;

mixing terephthalic acid, butanediol and tetrabutyl titanate, heating to 182 ℃, keeping the temperature, continuing to heat to 215 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 3.6 hours in a neon atmosphere to obtain a butylene terephthalate compound; the molar ratio of terephthalic acid to butanediol is 1: 2.5; the mass of tetrabutyl titanate is 0.008 wt% of that of terephthalic acid;

(5) preparing a high-barrier antibacterial oligomer;

mixing the high-barrier antibacterial prepolymer obtained in the step (2), butanediol adipate obtained in the step (3), ethylene glycol antimony and trimethyl phosphate, heating to 224 ℃, keeping the temperature, continuing to heat to 257 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 2.2 hours in a neon atmosphere to obtain a high-barrier antibacterial oligomer; the molar ratio of the high-barrier antibacterial prepolymer to the butanediol adipate esterified substance is 1: 380; the mass of the ethylene glycol antimony is 0.01 wt% of that of the butanediol adipate ester; the mass of the trimethyl phosphate is 0.04 wt% of that of the butanediol adipate ester;

(6) preparing a high-barrier antibacterial PBAT polymer;

mixing the butylene terephthalate esterified substance obtained in the step (4) with the high-barrier antibacterial oligomer obtained in the step (5), heating to 236 ℃, keeping the temperature, continuing to heat to 275 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2.1 hours in a neon atmosphere to obtain a high-barrier antibacterial PBAT polymer; wherein the molar ratio of the high-barrier antibacterial oligomer to the butanediol terephthalate is 1: 370.

The molecular structural formula of the prepared high-barrier antibacterial PBAT polymer is as follows:

wherein the structural formula of- (O-X-O) is as follows:

wherein represents the point of attachment of the branch to the nitrogen atom; x represents the degree of polymerization of a polybutylene adipate chain segment; y represents the degree of polymerization of the polybutylene terephthalate segment; the weight average molecular weight of the high-barrier antibacterial PBAT polymer is 2.6 multiplied by 10⁵(ii) a A melt index of 4.8g/10min measured at a temperature of 190 ℃ and a load of 2.16 kg; the melting point is 132 ℃; the carboxyl end group content is 31 mmol/kg; the bacteriostasis rate to escherichia coli is 92 percent, and the bacteriostasis rate to staphylococcus aureus is 85 percent; the biodegradation rate in 45 days was 21.3%.

And carrying out tape casting on the high-barrier antibacterial PBAT polymer to obtain the antibacterial PBAT barrier film, wherein the tape casting temperature is 150 ℃ and the width of a die lip of a tape casting die head is 0.5mm during tape casting.

The obtained antibacterial PBAT barrier film has a thickness of 25 μm and an oxygen transmission rate of 3.2cc/m²Day/0.1MPa, water vapor transmission rate of 132g/m²/day。

Example 6

A preparation method of a high-barrier antibacterial PBAT polymer comprises the following specific steps:

(1) preparing a high-barrier functional monomer;

mixing mannitol and DL-arginine in a molar ratio of 1:6.3, heating to 68 ℃, keeping the temperature, adding copper acetylacetonate and 2, 2-bipyridyl when a reaction system is in a uniform molten state, continuing heating to 80 ℃, and continuously reacting for 37min under a helium atmosphere to obtain a high-barrier functional monomer; the mass of the copper acetylacetonate is 0.055 wt% of the mass of the mannitol; the mass of the 2, 2-bipyridyl is 0.045 wt% of that of the mannitol;

(2) preparing a high-barrier antibacterial prepolymer;

mixing adipic acid, butanediol and the high-barrier function monomer obtained in the step (1), heating to 168 ℃, and continuously reacting for 1.8h in a helium atmosphere to obtain a high-barrier antibacterial prepolymer; wherein the molar ratio of the high-barrier functional monomer to the adipic acid is 1: 6.4; the molar ratio of adipic acid to butanediol is 1: 1.8;

(3) preparing butanediol adipate esterified substance;

mixing adipic acid and butanediol with a molar ratio of 1:1.18, heating to 139 ℃, keeping the temperature, continuing to heat to 177 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2.4 hours in a helium atmosphere to obtain a butanediol adipate compound;

(4) preparing butanediol terephthalate ester;

mixing terephthalic acid, butanediol and tetrabutyl titanate, heating to 184 ℃, keeping the temperature, continuing to heat to 220 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 3.9 hours in a helium atmosphere to obtain a butylene terephthalate compound; the molar ratio of terephthalic acid to butanediol is 1: 2.55; the mass of tetrabutyl titanate is 0.016 wt% of that of terephthalic acid;

(5) preparing a high-barrier antibacterial oligomer;

mixing the high-barrier antibacterial prepolymer obtained in the step (2), butanediol adipate obtained in the step (3), ethylene glycol antimony and trimethyl phosphate, heating to 228 ℃, keeping the temperature, continuing to heat to 258 ℃ when a reaction system is in a uniform molten state, and continuously reacting for 2.8 hours in a helium atmosphere to obtain a high-barrier antibacterial oligomer; the molar ratio of the high-barrier antibacterial prepolymer to the butanediol adipate esterified substance is 1: 450; the mass of the ethylene glycol antimony is 0.007 wt% of that of the butanediol adipate ester; the mass of the trimethyl phosphate is 0.035 wt% of that of the butanediol adipate;

(6) preparing a high-barrier antibacterial PBAT polymer;

mixing the butylene terephthalate esterified substance obtained in the step (4) with the high-barrier antibacterial oligomer obtained in the step (5), heating to 239 ℃, preserving heat, continuing heating to 268 ℃ when the reaction system is in a uniform molten state, and continuously reacting for 2.2 hours in a helium atmosphere to obtain a high-barrier antibacterial PBAT polymer; wherein the molar ratio of the high-barrier antibacterial oligomer to the butanediol terephthalate is 1: 385.

The molecular structural formula of the prepared high-barrier antibacterial PBAT polymer is as follows:

wherein the structural formula of- (O-X-O) is as follows:

wherein represents the point of attachment of the branch to the nitrogen atom; x represents the degree of polymerization of a polybutylene adipate chain segment; y represents the degree of polymerization of the polybutylene terephthalate segment; the weight average molecular weight of the high-barrier antibacterial PBAT polymer is 2.9 multiplied by 10⁵(ii) a A melt index of 3.7g/10min measured at a temperature of 190 ℃ and a load of 2.16 kg; the melting point is 139 ℃; the carboxyl end group content is 25 mmol/kg; the bacteriostasis rate to escherichia coli is 88 percent, and the bacteriostasis rate to staphylococcus aureus is 89 percent; the biodegradation rate in 45 days was 20.8%.

And carrying out tape casting on the high-barrier antibacterial PBAT polymer to obtain the antibacterial PBAT barrier film, wherein the tape casting temperature is 190 ℃ and the width of a die lip of a tape casting die head is 2mm during tape casting.

The thickness of the prepared antibacterial PBAT barrier film is 40 mu m, and the oxygen transmission rate is 8.1cc/m²Day/0.1MPa, water vapor transmission rate of 98g/m²/day。