High-molecular polymer with antibacterial slow-release function and preparation method of high-molecular polymer

Abstract

The invention relates to the technical field of functional high-molecular materials, and particularly discloses a high-molecular polymer with antibacterial and slow-release functions and a preparation method of the high-molecular polymer. A preparation method of a high-molecular polymer with antibacterial and slow-release functions comprises the following steps: S1, adding amino-terminated hyperbranched polyamide, p-formylbenzoic acid and a dehydrating agent into a reactor in an inert atmosphere, raising the temperature to 60-80 DEG C, reacting for 45-60 minutes, adding a carboxyl-containing heterocyclic compound, a catalyst and N, N-dimethylformamide, raising the temperature to 80-100 DEG C, reacting for 2-6 hours, adding a metal salt, and reacting for 2-6 hours to obtain a prepolymer; reacting for 1-2 hours, and cooling to obtain an antibacterial intermediate; s2, uniformly mixing the antibacterial intermediate, bio-based polyamide and an antioxidant in proportion in an inert atmosphere, extruding by an extruder, and cooling and granulating to obtain the high-molecular polymer. The high-molecular polymer prepared by the invention has excellent antibacterial performance and long-acting slow-release performance.

Description

Technical Field

[0001] This application relates to the technical field of functional polymer materials, and more specifically, to a polymer with antibacterial sustained-release function and its preparation method. Background Technology

[0002] Polyamide materials are widely used in antibacterial fabrics, functional coatings, medical and hygiene products, and household products due to their excellent mechanical strength, wear resistance, processability, and chemical resistance. However, pure polyamide materials do not have active antibacterial properties and cannot meet the needs of hygiene protection and high-end products. Therefore, antibacterial modification of polyamide materials has become the core direction of industry research and industrialization. Existing polyamide antibacterial modification technologies mostly employ organic antibacterial agents or simple inorganic antibacterial agent compound schemes, which have significant drawbacks and cannot simultaneously guarantee long-term antibacterial effect, processing stability, and safety of use. Firstly, although organic antibacterial agents such as chitosan and chitosan oligosaccharides have a certain degree of biocompatibility, they are only physically blended with the polyamide matrix. During repeated washing of fabrics, long-term immersion of coatings in water, and long-term use of products, they are prone to migration, dissolution, and loss, leading to a rapid decline in antibacterial performance and making it impossible to guarantee long-term antibacterial effect. Moreover, these organic antibacterial agents have poor heat resistance and are prone to thermal degradation and carbonization during high-temperature melt processing of polyamide (above 180°C), resulting in the loss of antibacterial activity.

[0003] Patent application CN102241887A discloses an antibacterial polyamide material, which is composed of polyamide resin, antibacterial agent, compatibilizer and antioxidant; the antibacterial agent is one or more of chitosan, chitosan oligosaccharide and its derivatives.

[0004] In this technical solution, the chitosan-based organic antibacterial agent and the polyamide matrix are mainly bonded through physical blending. The bonding force is weak, the antibacterial agent is easily lost, and the heat resistance of the chitosan-based antibacterial agent is a prominent shortcoming. It cannot be adapted to the mainstream processing technology of polyamide such as high-temperature melt extrusion, spinning, and injection molding. The material lacks both antibacterial durability and processing stability, which severely limits its application scenarios. Summary of the Invention

[0005] To address the shortcomings of existing organic antibacterial agents, such as easy loss and poor heat resistance, this application provides a polymer with antibacterial sustained-release function and its preparation method.

[0006] In a first aspect, this application provides a method for preparing a polymer with antibacterial sustained-release function, employing the following technical solution: A method for preparing a polymer with antibacterial sustained-release function includes the following steps: S1: Under an inert atmosphere, terminal amino hyperbranched polyamide, p-aldehyde benzoic acid and dehydrating agent are added to a reactor, the temperature is raised to 60~80℃, and the reaction is carried out for 45~60 min. Then, a carboxyl-containing heterocyclic compound, a catalyst and N,N-dimethylformamide are added, the temperature is raised to 80~100℃, and the reaction is carried out for 2~6 h. Then, a metal salt is added, and the reaction is carried out for 1~2 h. After cooling, an antibacterial intermediate is obtained. S2: In an inert atmosphere, antibacterial intermediates, bio-based polyamides and antioxidants are mixed in proportion, extruded through an extruder, cooled and granulated to obtain a high molecular polymer.

[0007] In this technical solution, aldehyde benzoic acid forms partial imine bonds with amino-terminated hyperbranched polyamide to construct a reversible network. Subsequently, a carboxyl-containing heterocyclic compound is incorporated into the hyperbranched network through an amidation reaction, introducing metal coordination sites. Finally, metal ions are introduced to achieve anchoring through coordination. The resulting antibacterial intermediate is then melt-blended with bio-based polyamide and antioxidant under an inert atmosphere, followed by extrusion granulation to uniformly disperse the antibacterial component in the polyamide matrix, ultimately yielding a polymer with long-lasting antibacterial properties, sustained-release characteristics, and excellent processing stability.

[0008] Preferably, the bio-based polyamide is one or more of PA11, PA510, and PA610.

[0009] Preferably, the extruder is a twin-screw extruder, and the temperature ranges of each section of the twin-screw extruder are 200~210℃, 210~220℃, 220~230℃, 230~235℃ and 230~235℃ respectively.

[0010] Preferably, the dehydrating agent is a molecular sieve.

[0011] Preferably, the amount of the dehydrating agent is 2 to 3 times the mass of p-aldehyde benzoic acid.

[0012] Preferably, the catalyst is a carbodiimide, and more preferably dicyclohexylcarbodiimide.

[0013] Preferably, the amount of catalyst used is 3% to 5% of the total molar amount of p-aldehyde benzoic acid and carboxyl-containing heterocyclic compounds.

[0014] In this technical solution, carbodiimide catalysts can activate carboxyl groups, promote their amidation reaction with amino groups, and achieve effective grafting under low temperature conditions.

[0015] Preferably, the antioxidant includes antioxidant 1098 and antioxidant 168.

[0016] Preferably, the molar ratio of the terminal amino hyperbranched polyamide (based on the terminal amino group), p-aldehyde benzoic acid, carboxyl-containing heterocyclic compound and metal salt is 1:(0.2~0.3):(0.15~0.25):(0.08~0.15).

[0017] In this technical solution, the preferred molar ratio is adopted to ensure that the proportions of each functional component are coordinated: the aldehyde group of p-aldehyde benzoic acid forms an imine bond with some of the terminal amino groups, and the carboxyl-containing heterocyclic compound undergoes an amidation reaction with the remaining terminal amino groups to introduce metal coordination sites.

[0018] Preferably, the mass ratio of the antibacterial intermediate, the bio-based polyamide, and the antioxidant is (5~25):(75~95):(0.2~0.5).

[0019] Preferably, the carboxyl-containing heterocyclic compound is one or more of 3-hydroxy-2-pyridinecarboxylic acid and 4-pyridinecarboxylic acid.

[0020] In this technical solution, the carboxyl group of the carboxyl-containing heterocyclic compound participates in the amidation reaction and is incorporated into the hyperbranched network. Its heterocyclic nitrogen atom can coordinate with metal ions to form a stable complex structure.

[0021] Preferably, the metal salt is one or more of silver acetate, zinc acetate, and copper acetate.

[0022] In this technical solution, metal ions are ensured to be uniformly dispersed and fully combined with coordination sites in the network, and acetate ions have few side reactions in subsequent processing.

[0023] Preferably, in step S2, after the bio-based polyamide, a step of adding toluene diisocyanate accounting for 1% to 5% of the mass of the antibacterial intermediate is further included.

[0024] In this technical solution, toluene diisocyanate can react with residual amino groups in the hyperbranched network during melt blending to form additional crosslinking points, thereby regulating the density of the network and affecting the release behavior of antibacterial ions.

[0025] Preferably, in step S1, after adding the carboxyl-containing heterocyclic compound, the step further includes adding quercetin and / or gallic acid.

[0026] Preferably, the molar ratio of quercetin or gallic acid to terminal amino hyperbranched polyamide (based on terminal amino groups) is (0.03~0.07):1.

[0027] In this technical solution, quercetin contains multiple phenolic hydroxyl groups, which can coordinate with metal ions; gallic acid contains both phenolic hydroxyl groups and carboxyl groups, and its carboxyl groups can participate in amidation reactions to connect to the network, while the phenolic hydroxyl groups are used for metal coordination.

[0028] Secondly, this application provides a polymer with antibacterial sustained-release function prepared by the above-mentioned preparation method.

[0029] In this technical solution, metal ions in the polymer are slowly released during use based on the synergistic effect of chemical anchoring and physical barrier, giving the material long-lasting antibacterial properties and processing stability.

[0030] In summary, this application has the following beneficial effects: In the antibacterial intermediate of this application, the imine bond introduced by p-aldehyde benzoic acid can undergo hydrolysis under slightly acidic conditions, causing a change in the network structure; the heterocyclic nitrogen atom provided by the carboxyl-containing heterocyclic compound forms a coordination structure with the metal ion; and the reaction forms a three-dimensional network that physically blocks the diffusion of metal ions. Through the synergistic effect of the above chemical anchoring and physical barrier, the metal ions are slowly released during use, endowing the polymer with long-lasting antibacterial properties and processing stability. Optional crosslinking agents can further regulate the network density, and optional phenolic compounds can enhance the coordination anchoring of metal ions. Detailed Implementation

[0031] The present application will be further described in detail below with reference to the embodiments.

[0032] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0033] The following are examples and comparative examples: In the terminal amino hyperbranched polyamide, the molecular weight distribution is 800~1000g / mol and the amino content is 7~9mol / mol. In the following examples, it is added according to the average content, that is, based on 8mol of amino content per 900g.

[0034] Example 1 The preparation method of the polymer with antibacterial sustained-release function in this embodiment includes the following steps: S1: Under a nitrogen atmosphere, 112.5 g of terminal amino hyperbranched polyamide (amino content 1.0 mol), 0.2 mol of p-aldehyde benzoic acid, and 60 g of molecular sieve were added to a reactor. The stirring device was turned on and the speed was set to 150 rpm. The temperature was raised to 60℃ and the reaction was carried out for 60 min. Then, 0.15 mol of 3-hydroxy-2-pyridinecarboxylic acid, 0.018 mol of dicyclohexylcarbodiimide, and 360 mL of N,N-dimethylformamide were added. The temperature was raised to 80℃ and the reaction was carried out for 4 h. A mixture of silver acetate (0.08 mol of silver acetate and 40 mL of N,N-dimethylformamide were mixed evenly) was slowly added dropwise. After the addition was completed, the reaction was continued for 1.5 h. The mixture was cooled, filtered to remove the molecular sieve, and the filtrate was poured into a large amount of anhydrous ethanol to precipitate. The precipitate was filtered, washed twice with anhydrous ethanol, dried under vacuum at 60℃ to constant weight, and pulverized to obtain the antibacterial intermediate. S2: Under a nitrogen atmosphere, the antibacterial intermediate, bio-based polyamide and antioxidant are mixed evenly at a mass ratio of 5:95:0.2 and fed into the barrel of a twin-screw extruder. After melt blending, the mixture is extruded, air-cooled and granulated to obtain a polymer with antibacterial sustained-release function.

[0035] Among them, the antioxidants include antioxidant 1098 and antioxidant 168 in a mass ratio of 3:1; the bio-based polyamide is PA11; The twin-screw extruder temperature settings are: Zone 1 200℃, Zone 2 210℃, Zone 3 220℃, Zone 4 230℃, Die head 230℃, and screw speed 300rpm.

[0036] Example 2 The preparation method of the polymer with antibacterial sustained-release function in this embodiment includes the following steps: S1: Under a nitrogen atmosphere, 112.5 g of terminal amino hyperbranched polyamide (amino content 1.0 mol), 0.3 mol of p-aldehyde benzoic acid, and 135 g of molecular sieve were added to a reactor. The stirring device was turned on and the speed was set to 150 rpm. The temperature was raised to 80℃ and the reaction was carried out for 45 min. Then, 0.25 mol of 3-hydroxy-2-pyridinecarboxylic acid, 0.017 mol of dicyclohexylcarbodiimide, and 360 mL of N,N-dimethylformamide were added. The temperature was raised to 100℃ and the reaction was carried out for 2 h. A mixture of silver acetate (0.1 mol of silver acetate, 0.05 mol of zinc acetate, and 40 mL of N,N-dimethylformamide were mixed evenly) was slowly added dropwise. After the addition was completed, the reaction was continued for 1 h. The mixture was cooled, filtered to remove the molecular sieve, and the filtrate was poured into a large amount of anhydrous ethanol to precipitate. The precipitate was filtered, washed twice with anhydrous ethanol, dried under vacuum at 60℃ to constant weight, and pulverized to obtain the antibacterial intermediate. S2: Under a nitrogen atmosphere, the antibacterial intermediate, bio-based polyamide and antioxidant are mixed evenly at a mass ratio of 25:75:0.5 and fed into the barrel of a twin-screw extruder. After melt blending, the mixture is extruded, air-cooled and granulated to obtain a polymer with antibacterial sustained-release function.

[0037] Among them, the antioxidants include antioxidant 1098 and antioxidant 168 in a mass ratio of 3:1; the bio-based polyamide is PA11; The twin-screw extruder temperature settings are: Zone 1 210℃, Zone 2 220℃, Zone 3 230℃, Zone 4 235℃, Die head 235℃, and screw speed 280 rpm.

[0038] Example 3 The preparation method of the polymer with antibacterial sustained-release function in this embodiment includes the following steps: S1: Under a nitrogen atmosphere, 112.5 g of terminal amino hyperbranched polyamide (amino content 1.0 mol), 0.25 mol of p-aldehyde benzoic acid, and 90 g of molecular sieve were added to a reactor. The stirring device was turned on and the speed was set to 150 rpm. The temperature was raised to 80℃ and the reaction was carried out for 50 min. Then, 0.1 mol of 3-hydroxy-2-pyridinecarboxylic acid, 0.1 mol of 4-pyridinecarboxylic acid, 0.018 mol of dicyclohexylcarbodiimide, and 360 mL of N,N-dimethylformamide were added. The temperature was raised to 90℃ and the reaction was carried out for 6 h. A mixture of silver acetate (0.1 mol of silver acetate, 0.02 mol of copper acetate, and 40 mL of N,N-dimethylformamide were mixed evenly) was slowly added dropwise. After the addition was completed, the reaction was continued for 1 h. The mixture was cooled, filtered to remove the molecular sieve, and the filtrate was poured into a large amount of anhydrous ethanol to precipitate. The filtrate was filtered, washed twice with anhydrous ethanol, dried under vacuum at 60℃ to constant weight, and pulverized to obtain the antibacterial intermediate. S2: Under a nitrogen atmosphere, the antibacterial intermediate, bio-based polyamide, toluene diisocyanate and antioxidant are mixed evenly and fed into the barrel of a twin-screw extruder. After melt blending, the mixture is extruded, air-cooled and granulated to obtain a polymer with antibacterial sustained-release function.

[0039] The mass ratio of antibacterial intermediate, bio-based polyamide, and antioxidant is 15:85:0.35; the amount of toluene diisocyanate is 1% of the mass of the antibacterial intermediate; the antioxidants include antioxidant 1098 and antioxidant 168 in a mass ratio of 3:1; and the bio-based polyamides are PA11 and PA510 in a mass ratio of 1:2. The twin-screw extruder temperature settings are: Zone 1 210℃, Zone 2 220℃, Zone 3 230℃, Zone 4 235℃, Die head 235℃, and screw speed 280 rpm.

[0040] Example 4 The preparation method of the polymer with antibacterial sustained-release function in this embodiment includes the following steps: S1: Under a nitrogen atmosphere, 112.5 g of terminal amino hyperbranched polyamide (amino content 1.0 mol), 0.25 mol of p-aldehyde benzoic acid, and 90 g of molecular sieve were added to a reactor. The stirring device was turned on and the speed was set to 150 rpm. The temperature was raised to 80℃ and the reaction was carried out for 50 min. Then, 0.2 mol of 3-hydroxy-2-pyridinecarboxylic acid, 0.018 mol of dicyclohexylcarbodiimide, and 360 mL of N,N-dimethylformamide were added. The temperature was raised to 90℃ and the reaction was carried out for 6 h. A mixture of silver acetate (0.1 mol of silver acetate, 0.02 mol of copper acetate, and 40 mL of N,N-dimethylformamide were mixed evenly) was slowly added dropwise. After the addition was completed, the reaction was continued for 1 h. The mixture was cooled, filtered to remove the molecular sieve, and the filtrate was poured into a large amount of anhydrous ethanol to precipitate. The precipitate was filtered, washed twice with anhydrous ethanol, dried under vacuum at 60℃ to constant weight, and pulverized to obtain the antibacterial intermediate. S2: Under a nitrogen atmosphere, the antibacterial intermediate, bio-based polyamide, toluene diisocyanate and antioxidant are mixed evenly and fed into the barrel of a twin-screw extruder. After melt blending, the mixture is extruded, air-cooled and granulated to obtain a polymer with antibacterial sustained-release function.

[0041] The mass ratio of antibacterial intermediate, bio-based polyamide, and antioxidant is 15:85:0.35; the amount of toluene diisocyanate is 3% of the mass of antibacterial intermediate; the antioxidants include antioxidant 1098 and antioxidant 168 in a mass ratio of 3:1; and the bio-based polyamides are PA11 and PA610 in a mass ratio of 1:2. The twin-screw extruder temperature settings are: Zone 1 210℃, Zone 2 220℃, Zone 3 230℃, Zone 4 235℃, Die head 235℃, and screw speed 280 rpm.

[0042] Example 5 The preparation method of the polymer with antibacterial sustained-release function in this embodiment includes the following steps: S1: Under a nitrogen atmosphere, 112.5 g of terminal amino hyperbranched polyamide (amino content 1.0 mol), 0.25 mol of p-aldehyde benzoic acid, and 90 g of molecular sieve were added to a reactor. The stirring device was turned on and the speed was set to 150 rpm. The temperature was raised to 80℃ and the reaction was carried out for 50 min. Then, 0.15 mol of 3-hydroxy-2-pyridinecarboxylic acid, 0.05 mol of 4-pyridinecarboxylic acid, 0.018 mol of dicyclohexylcarbodiimide, and 360 mL of N,N-dimethylformamide were added. The temperature was raised to 90℃ and the reaction was carried out for 6 h. A mixture of silver acetate (0.1 mol of silver acetate, 0.02 mol of copper acetate, and 40 mL of N,N-dimethylformamide were mixed evenly) was slowly added dropwise. After the addition was completed, the reaction was continued for 1 h. The mixture was cooled, filtered to remove the molecular sieve, and the filtrate was poured into a large amount of anhydrous ethanol to precipitate. The precipitate was filtered, washed twice with anhydrous ethanol, dried under vacuum at 60℃ to constant weight, and pulverized to obtain the antibacterial intermediate. S2: Under a nitrogen atmosphere, the antibacterial intermediate, bio-based polyamide, toluene diisocyanate and antioxidant are mixed evenly and fed into the barrel of a twin-screw extruder. After melt blending, the mixture is extruded, air-cooled and granulated to obtain a polymer with antibacterial sustained-release function.

[0043] The mass ratio of antibacterial intermediate, bio-based polyamide, and antioxidant is 15:85:0.35; the amount of toluene diisocyanate is 5% of the mass of the antibacterial intermediate; the antioxidants include antioxidant 1098 and antioxidant 168 in a mass ratio of 3:1; and the bio-based polyamides are PA11 and PA510 in a mass ratio of 1:2. The twin-screw extruder temperature settings are: Zone 1 210℃, Zone 2 220℃, Zone 3 230℃, Zone 4 235℃, Die head 235℃, and screw speed 280 rpm.

[0044] Example 6 The difference between this embodiment and embodiment 5 is as follows: The preparation method of the polymer with antibacterial sustained-release function in this embodiment includes the following steps: S1: Under a nitrogen atmosphere, 112.5 g of terminal amino hyperbranched polyamide (amino content 1.0 mol), 0.25 mol of p-aldehyde benzoic acid, and 90 g of molecular sieve were added to a reactor. The stirring device was turned on and the speed was set to 150 rpm. The temperature was raised to 80℃ and the reaction was carried out for 50 min. Then, 0.22 mol of 3-hydroxy-2-pyridinecarboxylic acid, 0.03 mol of quercetin, 0.02 mol of dicyclohexylcarbodiimide, and 360 mL of N,N-dimethylformamide were added. The temperature was raised to 90℃ and the reaction was carried out for 6 h. A mixture of silver acetate (0.1 mol of silver acetate, 0.02 mol of copper acetate, and 40 mL of N,N-dimethylformamide were mixed evenly) was slowly added dropwise. After the addition was completed, the reaction was continued for 1 h. The mixture was cooled, filtered to remove the molecular sieve, and the filtrate was poured into a large amount of anhydrous ethanol to precipitate. The filtrate was filtered, washed twice with anhydrous ethanol, dried under vacuum at 60℃ to constant weight, and pulverized to obtain the antibacterial intermediate. The rest is the same as in Example 5.

[0045] Example 7 The difference between this embodiment and embodiment 5 is as follows: The preparation method of the polymer with antibacterial sustained-release function in this embodiment includes the following steps: S1: Under a nitrogen atmosphere, 112.5 g of terminal amino hyperbranched polyamide (amino content 1.0 mol), 0.25 mol of p-aldehyde benzoic acid, and 90 g of molecular sieve were added to a reactor. The stirrer was turned on and the speed was set to 150 rpm. The temperature was raised to 80℃ and the reaction was carried out for 50 min. Then, 0.22 mol of 3-hydroxy-2-pyridinecarboxylic acid, 0.03 mol of quercetin, 0.04 mol of gallic acid, and 0.02 mol of dicyclohexylcarbodiimide were added. Add 360 mL of N,N-dimethylformamide and continue heating to 90 °C. React for 6 h. Slowly add a mixture of silver acetate (0.1 mol silver acetate, 0.02 mol copper acetate and 40 mL N,N-dimethylformamide are mixed evenly). After the addition is complete, continue the reaction for 1 h. Cool, filter to remove molecular sieve, pour the filtrate into a large amount of anhydrous ethanol to precipitate, filter, wash twice with anhydrous ethanol, vacuum dry at 60 °C to constant weight, pulverize to obtain the antibacterial intermediate. The rest is the same as in Example 5.

[0046] Comparative Example 1 The preparation method of the comparative example of a polymer with antibacterial sustained-release function includes the following steps: S1: Under a nitrogen atmosphere, 112.5 g of terminal amino hyperbranched polyamide (amino content 1.0 mol), 0.15 mol of 3-hydroxy-2-pyridinecarboxylic acid, 0.018 mol of dicyclohexylcarbodiimide, and 360 mL of N,N-dimethylformamide were added to a reactor. The temperature was raised to 80 °C, and the reaction was carried out for 4 h. A mixture of silver acetate (0.08 mol of silver acetate and 40 mL of N,N-dimethylformamide were mixed evenly) was slowly added dropwise. After the addition was completed, the reaction was continued for 1.5 h. The mixture was cooled, filtered, and the filtrate was poured into a large amount of anhydrous ethanol to precipitate. The filtrate was filtered, washed twice with anhydrous ethanol, dried under vacuum at 60 °C to constant weight, and pulverized to obtain an antibacterial intermediate. S2: Under a nitrogen atmosphere, the antibacterial intermediate, bio-based polyamide and antioxidant are mixed evenly at a mass ratio of 5:95:0.2 and fed into the barrel of a twin-screw extruder. After melt blending, the mixture is extruded, air-cooled and granulated to obtain a polymer with antibacterial sustained-release function.

[0047] Among them, the antioxidants include antioxidant 1098 and antioxidant 168 in a mass ratio of 3:1; the bio-based polyamide is PA11; The twin-screw extruder temperature settings are: Zone 1 200℃, Zone 2 210℃, Zone 3 220℃, Zone 4 230℃, Die head 230℃, and screw speed 300rpm.

[0048] Comparative Example 2 The preparation method of the comparative example of a polymer with antibacterial sustained-release function includes the following steps: S1: Under a nitrogen atmosphere, 112.5 g of terminal amino hyperbranched polyamide (amino content 1.0 mol), 0.2 mol of p-aldehyde benzoic acid, and 60 g of molecular sieve were added to a reactor. The stirring device was turned on and the speed was set to 150 rpm. The temperature was raised to 60℃ and the reaction was carried out for 60 min. 0.018 mol of dicyclohexylcarbodiimide and 360 mL of N,N-dimethylformamide were added. The temperature was raised to 80℃ and the reaction was carried out for 4 h. A mixture of silver acetate (0.08 mol of silver acetate and 40 mL of N,N-dimethylformamide were mixed evenly) was slowly added dropwise. After the addition was completed, the reaction was carried out for 1.5 h. The mixture was cooled, filtered to remove the molecular sieve, and the filtrate was poured into a large amount of anhydrous ethanol to precipitate. The filtrate was filtered, washed twice with anhydrous ethanol, dried under vacuum at 60℃ to constant weight, and pulverized to obtain the antibacterial intermediate. S2: Under a nitrogen atmosphere, the antibacterial intermediate, bio-based polyamide and antioxidant are mixed evenly at a mass ratio of 5:95:0.2 and fed into the barrel of a twin-screw extruder. After melt blending, the mixture is extruded, air-cooled and granulated to obtain a polymer with antibacterial sustained-release function.

[0049] Among them, the antioxidants include antioxidant 1098 and antioxidant 168 in a mass ratio of 3:1; the bio-based polyamide is PA11; The twin-screw extruder temperature settings are: Zone 1 200℃, Zone 2 210℃, Zone 3 220℃, Zone 4 230℃, Die head 230℃, and screw speed 300rpm.

[0050] Performance testing The polymers with antibacterial sustained-release function prepared in Examples 1-7 and Comparative Examples 1-2 were subjected to the following performance tests, and the test results are shown in Tables 1 and 2.

[0051] 1. Antibacterial performance testing: Referring to GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Shaking method", *Escherichia coli* (ATCC 25922) and *Staphylococcus aureus* (ATCC 6538) were selected as test bacteria. After pulverizing the polymer with antibacterial sustained-release function, 0.75 g was accurately weighed, sterilized, and then added to 70 mL of phosphate buffer (pH approximately 7.3 ± 0.1) and 5 mL of bacterial suspension (concentration approximately 1 × 10⁻⁶). 5 In a conical flask containing (CFU / mL) of nutrient agar, the culture was incubated at 36±1℃ and 150 r / min for 18 h with shaking. The viable bacterial concentration before and after shaking was determined using the nutrient agar pour plate counting method, and the inhibition rate was calculated. Antibacterial rate (%) = (W t -Q t ) / W t ; Among them, W t Q represents the average viable bacterial concentration (CFU / mL) after shaking three control samples. t The average viable bacterial concentration (CFU / mL) of the three test samples after shaking was calculated. Pure bio-based polyamide was used as a blank control group. Three parallel samples were set up in each group, and the average value was taken. 2. Antibacterial sustained-release performance test: Static leaching method was used: Polymers with antibacterial sustained-release function were prepared into sheets of 10mm×10mm×2mm, accurately weighed and then soaked in 50mL of leaching medium, and shaken at 37℃ (100rpm). The leaching medium was divided into 3 groups: (1) deionized water; (2) Escherichia coli culture medium: each liter contained 10.0g tryptone, 5.0g yeast powder and 5.0g sodium chloride, the pH was adjusted to 7.0±0.2, and after high-pressure sterilization at 121℃ for 15min, Escherichia coli ATCC25922 was inoculated, and the initial bacterial concentration was about 1×10 5 CFU / mL; (3) Staphylococcus aureus culture medium: each liter contains 17.0g tryptone, 3.0g soybean peptone, 5.0g sodium chloride, 2.5g dipotassium hydrogen phosphate, and 2.5g glucose. The pH is adjusted to 7.3±0.2. After autoclaving at 121℃ for 15min, Staphylococcus aureus ATCC 6538 is inoculated. The initial bacterial concentration is about 1×10⁻⁶. 5CFU / mL; 2mL samples were taken after 1 day, and the concentration of metal ions in the leachate was determined by inductively coupled plasma atomic emission spectrometry, and the release rate per unit area was calculated. Release rate (μg / (cm) 2 ·h))=C×V / (A×t; Where C is the concentration of metal ions in the leachate (μg / mL), V is the volume of the leachate medium (mL), and A is the surface area of ​​the sample (cm²). 2 ), t is the leaching time (h), and 3 parallel samples are set for each group, and the average value is taken.

[0052] 3. Mechanical property testing: In accordance with GB / T 1040.1-2018 "Determination of tensile properties of plastics", standard specimens were prepared and tensile strength was measured.

[0053] Table 1. Antibacterial rate and tensile strength of the polymers prepared in Examples 1-7 and Comparative Examples 1-2

[0054] Table 2. Antibacterial sustained-release properties of the polymers prepared in Examples 1-7 and Comparative Examples 1-2

[0055] As can be seen from the performance test results in Tables 1 and 2, the polymers prepared in Examples 1-7 and Comparative Examples 1-2 all exhibited high antibacterial rates against Escherichia coli and Staphylococcus aureus. However, there were significant differences in the tensile strength and metal ion release rate of the polymers in Examples 1-7 and Comparative Examples 1-2. This indicates that the coordination sites introduced by 3-hydroxy-2-pyridinecarboxylic acid and p-aldehyde benzoic acid, in synergy with the network structure formed between the terminal amino hyperbranched polyamide, can not only effectively anchor antibacterial metal ions and inhibit the explosive release of metal ions to achieve long-term controllable sustained release, but also improve the compatibility and structural stability of the system. At the same time, with the increase of toluene diisocyanate, the mechanical properties of the polymer were improved. The addition of quercetin and gallic acid further enhanced the coordination effect of metal ions, reduced the release rate, and optimized the mechanical properties, so that the material can maintain excellent antibacterial properties while possessing better mechanical properties and service durability.

[0056] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a polymer with antibacterial sustained-release function, characterized in that, Includes the following steps: S1: Under an inert atmosphere, terminal amino hyperbranched polyamide, p-aldehyde benzoic acid and dehydrating agent are added to a reactor, the temperature is raised to 60~80℃, and the reaction is carried out for 45~60 min. Then, a carboxyl-containing heterocyclic compound, a catalyst and N,N-dimethylformamide are added, the temperature is raised to 80~100℃, and the reaction is carried out for 2~6 h. Then, a metal salt is added, and the reaction is carried out for 1~2 h. After cooling, an antibacterial intermediate is obtained. S2: In an inert atmosphere, antibacterial intermediates, bio-based polyamides and antioxidants are mixed in proportion, extruded through an extruder, cooled and granulated to obtain a high molecular polymer.

2. The method for preparing the polymer with antibacterial sustained-release function according to claim 1, characterized in that, The bio-based polyamide is one or more of PA11, PA510, and PA610.

3. The method for preparing the polymer with antibacterial sustained-release function according to claim 2, characterized in that, The molar ratio of the terminal amino hyperbranched polyamide (based on the terminal amino group), p-aldehyde benzoic acid, carboxyl-containing heterocyclic compound and metal salt is 1:(0.2~0.3):(0.15~0.25):(0.08~0.15).

4. The method for preparing the polymer with antibacterial sustained-release function according to claim 2, characterized in that, The mass ratio of the antibacterial intermediate, bio-based polyamide, and antioxidant is (5~25):(75~95):(0.2~0.5).

5. The method for preparing the polymer with antibacterial sustained-release function according to claim 1, characterized in that, The carboxyl-containing heterocyclic compound is one or more of 3-hydroxy-2-pyridinecarboxylic acid and 4-pyridinecarboxylic acid.

6. The method for preparing the polymer with antibacterial sustained-release function according to claim 1, characterized in that, The metal salt is one or more of silver acetate, zinc acetate, and copper acetate.

7. The method for preparing the polymer with antibacterial sustained-release function according to claim 1, characterized in that, In step S2, after the bio-based polyamide, a step of adding 1% to 5% toluene diisocyanate by weight of the antibacterial intermediate is also included.

8. The method for preparing the polymer with antibacterial sustained-release function according to claim 1, characterized in that, In step S1, after adding the carboxyl-containing heterocyclic compound, the step further includes adding quercetin and / or gallic acid.

9. The method for preparing the polymer with antibacterial sustained-release function according to claim 8, characterized in that, The molar ratio of quercetin or gallic acid to the terminal amino hyperbranched polyamide (based on the terminal amino group) is (0.03~0.07):

1.

10. A polymer with antibacterial sustained-release function prepared by the preparation method according to any one of claims 1 to 9.

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