Full-bio-based multifunctional antibacterial nylon material as well as preparation method and application thereof

Abstract

The invention discloses a full-bio-based multifunctional antibacterial nylon material as well as a preparation method and application thereof, relates to the technical field of high-molecular polymers, and solves the problems that the preparation process of a nylon material in the prior art depends on petroleum resources, the function is single and the application scene is limited. The method comprises the following steps: reacting an aminocaprolactam solution with corresponding aldehyde / carboxylic acid / halogenated alkane, and purifying to obtain a cyclic lysine derivative monomer M; the preparation method comprises the following steps: mixing and heating a cyclic lysine derivative monomer M, an initiator and a catalyst, reacting, and purifying to obtain a nylon material PM; and carrying out quaternization reaction on the nylon PM solution and alkyl halide, and purifying to obtain the full-bio-based multifunctional nylon material P. The preparation method completely abandons the use of petroleum-based raw materials, realizes the multifunctional synergistic effect of antibacterial property, biocompatibility, antibacterial biofilm property, thermosensitivity and the like, and can be applied to the fields of antibacterial materials, biomedical materials, antibacterial biofilms and thermosensitivity materials.

Description

Technical Field

[0001] This invention relates to the field of polymer technology, specifically to a fully bio-based multifunctional antibacterial nylon material, its preparation method, and its application. Background Technology

[0002] Nylon, due to its excellent mechanical strength, abrasion resistance, and chemical resistance, is widely used in clothing, electronics, automotive parts, and office supplies. However, traditional nylon materials are highly dependent on non-renewable petroleum resources, and their production process generates high carbon emissions. In today's green and low-carbon economic context, the development of bio-based nylon materials (Nylon 55 and Nylon 56) based on renewable resources has become a research hotspot. These materials, through the use of bio-based pentanediamine, achieve partial substitution of bio-based raw materials, reducing dependence on petroleum resources to some extent. However, due to the high production cost and limited variety and functionality of these bio-based nylon materials, their current market share is low, and there is still a lack of high-end nylon products with special functionalities. Therefore, the development of novel fully bio-based nylon materials remains of great significance.

[0003] Currently, commercially available antibacterial nylon materials are mainly prepared through physical blending, which involves melt-blending nylon with functional reagents to impart special functionalities to nylon. However, nylon materials prepared by this method still have many shortcomings in terms of stability, durability, safety in use, and environmental friendliness. Chemical copolymerization is another effective approach to preparing functional nylon materials, which involves copolymerizing functional monomers with nylon monomers to impart special functionalities to nylon. However, the types of functional monomers that can be used for copolymerization are limited, and copolymerization usually alters the main chain structure of nylon, significantly affecting the inherent properties of the nylon material. Furthermore, current functional nylon materials often possess only a single function, lacking nylon products that simultaneously possess multiple special functions, which to some extent limits the application of nylon materials in diverse scenarios. For example, Chinese patent documents CN120399220A and CN115707727A disclose a method for preparing antibacterial nylon materials for use in textiles, daily necessities, packaging materials, or panels. In the preparation of these nylon materials, bio-based lysine is used as the starting material. Through efficient cyclization and post-modification reactions, functional cyclic lysine-derived monomers with the same cyclic structure as caprolactam are prepared. Copolymerization of these functional cyclic lysine-derived monomers with caprolactam can produce antibacterial nylon materials with an unchanged main chain structure, effectively improving antibacterial properties. However, the preparation of these nylon materials still requires the use of bio-based functional lysine derivatives for ring-opening copolymerization with petroleum-based caprolactam, resulting in a limited bio-based content in the obtained nylon material and a limited range of functional applications. In addition, Chinese patent documents CN119708470A and CN119859160A both disclose a flame-retardant nylon material for use in the automotive, textile, electronics, construction and packaging industries. This type of material partially replaces petroleum resources with renewable lysine resources, saving resources and being environmentally friendly while improving the flame-retardant effect. However, this type of material still cannot completely get rid of the use of petroleum-based caprolactam, and the resulting nylon material has relatively simple functionality, making it difficult to meet the diversified market application needs.

[0004] To address the issues of existing nylon material preparation processes relying on petroleum resources, limited functionality, and restricted application scenarios, the development of fully bio-based, multifunctional antibacterial nylon materials remains of great significance. Summary of the Invention

[0005] To address the problems of existing nylon material preparation processes relying on petroleum resources, limited functionality, and restricted applications, this invention proposes a fully bio-based multifunctional antibacterial nylon material, its preparation method, and its applications. The preparation scheme of this invention is as follows: A fully bio-based multifunctional antibacterial nylon material, the structural formula of which is shown in formula (Ⅰ) below: Equation (I); In the formula, R1 group and R2 group are straight-chain or branched C1 groups, respectively. 1-24 Aliphatic hydrocarbon group, substituted or unsubstituted C 3-12 Alicyclic hydrocarbon group, substituted or unsubstituted C 6-18 aryl, substituted or unsubstituted C 7-30 Any of the aralkyl groups, or the R1 and R2 groups on the same nitrogen atom together with the attached N atom to form a 5- to 7-membered saturated / or unsaturated heterocycle; The R3 group is hydrogen, a straight-chain or branched C group. 1-24 Aliphatic hydrocarbon group, substituted or unsubstituted C 3-12 Alicyclic hydrocarbon group, substituted or unsubstituted C 6-18 aryl, substituted or unsubstituted C 7-30 Any one of the aralkyl groups; X is any one of chloride, bromine, iodine, nitrate, bisulfate, bicarbonate, sulfonate, acetate, trifluoroacetate, and trifluoromethanesulfonate. m and n are the molar ratios of the corresponding repeating units to the total repeating units, respectively; where 0≤m≤1, 0≤n≤1, and m+n=1; the total number of each repeating unit ranges from 10 to 2500.

[0006] A method for preparing the above-mentioned fully bio-based multifunctional antibacterial nylon material includes the following steps: S1: Reaction of aminocaprolactam solution with the corresponding aldehyde / carboxylic acid / haloalkane, followed by purification, yields cyclic lysine-derived monomer M; S2: Cyclic lysine-derived monomer M, initiator, and catalyst are mixed, heated, and reacted. After purification, nylon material PM is obtained. S3: The nylon PM solution was subjected to a quaternization reaction with an alkyl halide, and after purification, the fully bio-based multifunctional antibacterial nylon material P was obtained.

[0007] Furthermore, the corresponding aldehyde / carboxylic acid / haloalkanes mentioned in S1 are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, benzyl chloride, monoiodocarbon, etc. 1～30 Alkanes, monobrominated C 1～30 Alkanes, diiodocarbons 2～30 Alkanes, dibromoC 2～30 One or at least two of alkanes and allyl bromides.

[0008] Further, the concentration of the aminocaprolactam solution is 0.1–1.0 mol / L; even further, the concentration of the aminocaprolactam solution is 0.2–0.5 mol / L.

[0009] Further, the solvent in the aminocaprolactam solution in S1 is any one of acetonitrile, methanol, ethanol, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, dimethyl sulfoxide, N,N-dimethylformamide, chloroform, and carbon tetrachloride.

[0010] Furthermore, the structure of the cyclic lysine-derived monomer M is shown in formula (II) below: Formula (II).

[0011] Further, the reaction temperature in S1 is 20–100°C, and the reaction time is 12 h; the molar ratio of aminocaprolactam to the corresponding aldehyde / carboxylic acid / haloalkane is 1:2–4; the purification steps are as follows: the reaction product is filtered to remove solids, the solvent is removed by vacuum distillation, deionized water is added to dissolve, sodium hydroxide is added to adjust the pH to 8–10, followed by extraction with an organic solvent, the organic phases are combined, the solvent is removed by vacuum distillation, and the residue is separated by column chromatography to complete the purification; the pH is adjusted to 7.5–14; the organic solvent is any one of dichloromethane, 1,2-dichloroethane, chloroform, carbon tetrachloride, diethyl ether, and ethyl acetate; the column chromatography eluent is dichloromethane and triethylamine, wherein the volume ratio of dichloromethane to triethylamine is 10–500:1.

[0012] Furthermore, when haloalkanes are used in S1, a base needs to be added for the reaction. The base is any one of sodium carbonate, potassium carbonate, cesium carbonate, sodium bicarbonate, sodium phosphate, potassium phosphate, sodium acetate, and sodium hydroxide. The ratio of aminocaprolactam to base is 1:1 to 5. Furthermore, when iodoalkanes are used, the reaction temperature is 40 to 60°C. When bromoalkanes are used, the reaction temperature is 70 to 80°C.

[0013] Further, the initiator in S2 is any one of benzoyl-protected caprolactam, acetyl-protected caprolactam, and benzoyl-protected N,N-dimethylcaprolactam; the catalyst is any one of sodium hydride, calcium hydride, potassium hydride, sodium methoxide, sodium ethoxide, sodium benzyl alcohol, sodium benzyl mercaptan, potassium bis(trimethylsilyl)amino, lithium bis(trimethylsilyl)amino, ethyl magnesium bromide, phenyl magnesium bromide, vinyl magnesium bromide, and propyl magnesium bromide; the molar ratio of the cyclic lysine-derived monomer M, the initiator, and the catalyst is 5 to 100:1:1.

[0014] Furthermore, the heating temperature in S2 is 80~180°C, and even further, the heating temperature is 140°C.

[0015] Furthermore, the reaction time in S2 is 1 to 48 h; even further, the reaction time is 3 h.

[0016] Furthermore, the purification steps described in S2 are as follows: quenching the reaction product, precipitation, and drying.

[0017] Further, the alkyl halide in S3 is any one of iodomethane, iodoethane, iodopropane, iodobutane, bromoethane, bromopropane, and bromobutane; the solvent in the nylon PM solution is any one of methanol, ethanol, propanol, acetonitrile, propionitrile, chloroform, carbon tetrachloride, and dimethyl sulfoxide; the temperature of the quaternization reaction is 25–100°C; and the reaction time is 10–48 h.

[0018] Further, the purification step described in S3 is as follows: the reaction product is removed by vacuum distillation to remove the reaction solvent, precipitated using a precipitation solvent, and dried; the precipitation solvent is any one of ethyl formate, methyl acetate, ethyl formate, ethyl ethyl ether, isopropyl ether, and methyl tert-butyl ether.

[0019] An application of the above-mentioned fully bio-based multifunctional antibacterial nylon material is applied in the fields of antibacterial materials, biomedical materials, antibacterial biofilms, and temperature-sensitive materials.

[0020] Furthermore, it can be applied to the preparation of antimicrobial materials for common pathogenic bacteria with broad-spectrum antimicrobial activity, the manufacture of biocompatible medical devices, the preparation of surface treatment materials that inhibit bacterial adhesion and biofilm formation, the preparation of temperature-responsive smart materials, and the preparation of temperature-sensing and intelligent control materials.

[0021] Compared with existing technologies, this invention solves the problems of existing technologies, such as reliance on petroleum resources in the preparation process of nylon materials, limited functionality, and limited application scenarios. Specifically, the beneficial effects are as follows: 1. Development of Fully Bio-based Nylon Materials: This invention uses aminocaprolactam, synthesized from bio-based lysine cyclization, as a raw material. It reacts with corresponding aldehydes / carboxylic acids / haloalkanes to synthesize cyclic lysine-derived monomers, which are then homopolymerized via ring-opening to prepare fully bio-based nylon materials. Quaternization modification with haloalkanes to varying degrees imparts a stable cationic structure, significantly enhancing antibacterial properties and yielding a fully bio-based multifunctional antibacterial nylon material. This method completely eliminates the use of petroleum-based raw materials, achieving 100% bio-based content. It not only embodies green chemistry principles in its synthetic pathway but also achieves low-carbon, environmentally friendly, and sustainable development throughout the material's lifecycle, meeting the current international demand for green polymer materials.

[0022] 2. The nylon material possesses multiple functions, including antibacterial properties, biocompatibility, antibacterial biofilm properties, and thermosensitivity: The nylon material provided by this invention not only achieves broad-spectrum antibacterial activity against common pathogens through quaternization modification, effectively inhibiting bacterial proliferation, but also destroys and removes established mature biofilms, thereby preventing long-term bacterial adhesion and drug resistance, significantly improving the material's anti-fouling and anti-infection properties. Simultaneously, the nylon material provided by this invention exhibits good compatibility with mammalian cells and adjustable thermosensitivity, with a minimum co-solution temperature close to human physiological temperature, ensuring high safety. In summary, the nylon material provided by this invention integrates antibacterial properties, biocompatibility, antibacterial biofilm properties, and thermosensitivity, achieving multifunctional synergy and expanding its broad application prospects in medical consumables, functional fibers, environmental purification, and smart materials.

[0023] 3. Suitable for large-scale applications: The method for preparing the all-bio-based multifunctional antibacterial nylon material provided by this invention is simple, efficient, and has mild reaction conditions and low production costs, making it suitable for large-scale production. Furthermore, the multifunctional synergistic effect can be achieved without adding additional functional reagents during the preparation process. The functionality of the nylon material can be controlled by changing the side chain structure, enabling customized production and making it suitable for large-scale industrial applications. Attached Figure Description

[0024] Figure 1 The 1H NMR spectrum of PM1, a diethyl-protected cyclic lysine-derived monomer; Figure 2 A synthetic route for fully bio-based multifunctional nylon; Figure 3 The image shows the 1H NMR spectrum of quaternized poly(diethylaminocaprolactam) P1. Detailed Implementation

[0025] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification. Many specific details are set forth in the following description to provide a thorough understanding of the present invention; however, the present invention may also be implemented in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0026] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0027] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0028] Example 1. S1: Aminocaprolactam (6.4 g, 0.05 mol) was dissolved in 200 mL of acetonitrile. Potassium carbonate (8.29 g, 0.06 mol) and bromoethane (13.08 g, 0.12 mol) were added sequentially at room temperature. The reaction mixture was heated to 85 °C and refluxed overnight. After the reaction was complete, the mixture was filtered. The filtrate was concentrated under reduced pressure, and deionized water was added to adjust the pH to 8–10. The aqueous phase was extracted with dichloromethane (3 × 50 mL). The resulting organic layers were combined, dried, concentrated, and purified by column chromatography using dichloromethane / triethylamine (100:1 v / v) as the eluent to obtain 7.8 g of diethyl-protected cyclic lysine derivative monomer M1, with a yield of 85%. M1 was characterized by 1H NMR spectroscopy as follows: 1 ¹H NMR (500 MHz, CDCl₃): δ 6.43–6.26 (s, 1H), 3.56–3.35 (m, 2H), 3.10–2.98 (m, 1H), 2.80–2.59 (m, 4H), 1.98–1.43 (m, 6H), 1.10–0.92 (t, 6H). Analysis of the ¹H NMR spectrum showed that the purity of M₁ was 99%.

[0029] S2: Under nitrogen protection, a 1 M solution of bis(trimethylsilyl)aminopotassium (KHMDS) in tetrahydrofuran (1 mL, 1 mmol) was added to a dry reaction flask. After removing the tetrahydrofuran, monomer M1 (1.84 g, 10 mmol) and benzoyl-protected caprolactam (0.217 g, 1 mmol) were added, and polymerization was carried out at 140 °C under nitrogen atmosphere for 3 h. After the reaction was completed, methanol (3 mL) was added to quench the reaction, and precipitation was achieved in an ethyl acetate / diethyl ether (1:1 volume ratio) mixed solvent. The precipitate was obtained by vacuum drying to obtain a diethyl-protected cyclic lysine-derived monomer PM1 (1.85 g, 90% yield). The structure of PM1 was characterized by 1H NMR spectroscopy as follows: 1 H NMR (500 MHz, CDCl3): δ 7.35–7.27 (s, 1H), 3.31–3.12 (m,2H), 3.12–3.03 (m, 1H), 2.61–2.38 (m, 4H), 1.81–1.26 (m, 6H), 1.06–0.93 (t,6H). like Figure 1The 1H NMR spectrum of PM1, a diethyl-protected cyclic lysine-derived monomer ( 1 1H-NMR; the purity of PM1 was determined to be 99% based on 1H NMR analysis.

[0030] S3: The precursor polymer PM1 (184 mg, 1 mmol) was dissolved in acetonitrile (2 mL) in a reaction flask, followed by the addition of bromoethane (218 mg, 2 mmol). The reaction mixture was refluxed at 85 °C for 24 h under nitrogen protection. After the reaction was complete, the solvent was removed by rotary evaporation, and the crude product precipitated in diethyl ether. The solid was collected by filtration and dried under vacuum to obtain quaternized poly(diethylaminocaprolactam) P1 (280 mg, yield 95%) with a quaternization degree of 100%. Figure 2 The synthetic route for fully bio-based multifunctional nylon is shown. The structure of P1 was characterized by 1H NMR spectroscopy as follows: 1 H NMR (500 MHz, DMSO-d6): δ 4.28-4.07 (m, 1H), 3.67–3.42 (m, 6H), 3.23–3.00 (m, 2H), 2.01–1.81 (m, 2H), 1.66–1.42 (m, 2H), 1.35–1.09 (m, 11H). Such as Figure 3 The image shows the 1H NMR spectrum of quaternized poly(diethylaminocaprolactam) P1. The purity of P1, as determined by 1H NMR analysis, is 99%.

[0031] Example 2. S1: M1 is prepared according to step S1 in Example 1; S2: PM1 is prepared according to step S2 in Example 1; S3: The precursor polymer PM1 (184 mg, 1 mmol) was dissolved in acetonitrile (2 mL) in a reaction flask, followed by the addition of bromoethane (109 mg, 1 mmol). The reaction mixture was refluxed at 85 °C for 24 h under nitrogen protection. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was precipitated in diethyl ether. The obtained solid was collected by filtration and dried under vacuum to obtain poly(diethylaminocaprolactam) P1-25% (200 mg, yield 95%) with a degree of quaternization of 25%.

[0032] Example 3. S1: M1 is prepared according to step S1 in Example 1; S2: PM1 is prepared according to step S2 in Example 1; S3: The precursor polymer PM1 (184 mg, 1 mmol) was dissolved in acetonitrile (2 mL) in a reaction flask, followed by the addition of bromoethane (164 mg, 1.5 mmol). The reaction mixture was refluxed at 85 °C for 24 h under nitrogen protection. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was precipitated in diethyl ether. The obtained solid was collected by filtration and dried under vacuum to obtain poly(diethylaminocaprolactam) P1-50% (229 mg, yield 96%) with a degree of quaternization of 50%.

[0033] Example 4. S1: M1 is prepared according to step S1 in Example 1; S2: PM1 is prepared according to step S2 in Example 1; S3: The precursor polymer PM1 (184 mg, 1 mmol) was dissolved in acetonitrile (2 mL) in a reaction flask, followed by the addition of bromoethane (196 mg, 1.8 mmol). The reaction mixture was refluxed at 85 °C for 24 h under nitrogen protection. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was precipitated in diethyl ether. The obtained solid was collected by filtration and dried under vacuum to obtain poly(diethylaminocaprolactam) P1-75% (252 mg, yield 95%) with a quaternization degree of 75%.

[0034] Example 5. S1: M1 is prepared according to step S1 in Example 1; S2: PM1 is prepared according to step S2 in Example 1; S3: The precursor polymer PM1 (184 mg, 1 mmol) was dissolved in acetonitrile (2 mL) in a reaction flask, followed by the addition of iodoethane (312 mg, 2 mmol). The reaction mixture was refluxed at 85 °C for 24 h under nitrogen protection. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was precipitated in diethyl ether. The solid obtained was collected by filtration and dried under vacuum to obtain 100% iodoanionic quaternized poly(diethylaminocaprolactam) P2 (323 mg, yield approximately 95%).

[0035] Example 6. S1: M1 is prepared according to step S1 in Example 1; S2: PM1 is prepared according to step S2 in Example 1; S3: The precursor polymer PM1 (184 mg, 1 mmol) was dissolved in acetonitrile (2 mL) in a reaction flask, followed by the addition of bromobutane (274 mg, 2 mmol). The reaction mixture was refluxed at 85 °C for 24 h under nitrogen protection. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was precipitated in diethyl ether. The obtained solid was collected by filtration and dried under vacuum to obtain poly(diethylaminocaprolactam) P3 (305 mg, yield 95%) with a quaternization degree of 100%.

[0036] Example 7. S1: M1 is prepared according to step S1 in Example 1; S2: PM1 is prepared according to step S2 in Example 1; S3: The precursor polymer PM1 (184 mg, 1 mmol) was dissolved in acetonitrile (2 mL) in a reaction flask, followed by the addition of bromohexane (330 mg, 2 mmol). The reaction mixture was refluxed at 85 °C for 24 h under nitrogen protection. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was precipitated in diethyl ether. The obtained solid was collected by filtration and dried under vacuum to obtain poly(diethylaminocaprolactam) P4 (331 mg, yield 95%) with a quaternization degree of 100%.

[0037] Example 8. S1: Aminocaprolactam (6.4 g, 0.05 mol) was dissolved in 200 mL of acetonitrile, and potassium carbonate (8.29 g, 0.06 mol) was added and stirred evenly at room temperature. Then, 1,4-dibromopentane (13.80 g, 0.06 mol) was added, and the mixture was heated under reflux at 85 °C for 10 h. After the reaction was completed, the filtrate was concentrated, deionized water was added, and the pH was adjusted to 8-10. The mixture was extracted three times with 50 mL of dichloromethane, and the organic phase was dried. Finally, the mixture was concentrated by rotary evaporation, and the crude product was purified by column chromatography using dichloromethane / triethylamine (volume ratio 100:1) as the eluent to obtain M2 (8.6 g, yield 88%). M2 was characterized by 1H NMR spectroscopy as follows: 1 H NMR (500 MHz, CDCl3): δ 6.32–5.94 (s, 1H), 3.68–3.48 (m, 1H), 3.38–2.96 (m, 4H), 2.93–2.40 (m, 1H), 2.03–1.33 (m, 10H), 1.06–0.94 (m, 3H).

[0038] S2: The difference from step S2 in Example 1 is that monomer M1 is replaced with monomer M2. The rest of the preparation methods and conditions are the same as in S2 in Example 1, and PM2 is obtained.

[0039] S3: The difference from step S3 in Example 1 is that monomer PM1 is replaced with monomer PM2. The rest of the preparation methods and conditions are the same as in S3 in Example 1, resulting in P5.

[0040] Example 9. S1: Aminocaprolactam (6.4 g, 0.05 mol) was dissolved in 200 mL of acetonitrile, and potassium carbonate (8.29 g, 0.06 mol) was added and stirred evenly at room temperature. Then, 1,4-dibromobutane (12.96 g, 0.06 mol) was added, and the mixture was heated under reflux at 85 °C for 10 h. After the reaction was completed, the filtrate was concentrated, deionized water was added, and the pH was adjusted to 8-10. The mixture was extracted three times with 50 mL of dichloromethane, and the organic phase was dried. Finally, the mixture was concentrated by rotary evaporation, and the crude product was purified by column chromatography using dichloromethane / triethylamine (volume ratio 100:1) as the eluent to obtain M3 (6.8 g, yield 75%). The structure of M3 was characterized by 1H NMR spectroscopy as follows: 1 H NMR (500 MHz, CDCl3): δ 6.04–5.86 (s, 1H), 3.78–3.65 (m, 1H), 3.06–2.95 (m, 2H), 2.71–2.43 (m, 4H), 2.01–1.45 (m, 10H).

[0041] S2: The difference from step S2 in Example 1 is that monomer M1 is replaced with monomer M3. The rest of the preparation methods and conditions are the same as in S2 in Example 1, and PM3 is obtained.

[0042] S3: The difference from step S3 in Example 1 is that monomer PM1 is replaced with monomer PM3. The rest of the preparation methods and conditions are the same as in S3 in Example 1, resulting in P6.

[0043] Example 10. S1: Aminocaprolactam (6.4 g, 0.05 mol) was dissolved in 200 mL of acetonitrile, and potassium carbonate (8.29 g, 0.06 mol) was added and stirred evenly at room temperature. Then, n-propyl bromide (14.76 g, 0.12 mol) was added, and the mixture was heated under reflux at 85 °C for 10 h. After the reaction was completed, the filtrate was concentrated, deionized water was added, and the pH was adjusted to 8-10. The mixture was extracted three times with 50 mL of dichloromethane, and the organic phase was dried. Finally, the mixture was concentrated by rotary evaporation, and the crude product was purified by column chromatography using dichloromethane / triethylamine (v / v ratio 100:1) as the eluent to obtain M4 (8.5 g, 80% yield). The structure of M4 was characterized by 1H NMR spectroscopy as follows: 1 H NMR (500 MHz, CDCl3): δ5.76–5.63 (s, 1H), 3.55–3.32 (m, 2H), 3.19–3.06 (m, 1H), 2.77–2.47 (m, 4H), 2.04–1.34 (m, 10H), 0.91–0.79 (t, 6H).

[0044] S2: The difference from step S2 in Example 1 is that monomer M1 is replaced with monomer M4. The rest of the preparation methods and conditions are the same as in S2 in Example 1, and PM4 is obtained.

[0045] S3: The difference from step S3 in Example 1 is that monomer PM1 is replaced with monomer PM4. The rest of the preparation methods and conditions are the same as in S3 in Example 1, resulting in P7.

[0046] Example 11. S1: Aminocaprolactam (6.4 g, 0.05 mol) was dissolved in 200 mL of acetonitrile, and potassium carbonate (8.29 g, 0.06 mol) was added and stirred evenly at room temperature. Then, 1,5-dibromopentane (13.80 g, 0.06 mol) was added, and the mixture was heated under reflux at 85 °C for 10 h. After the reaction was completed, the filtrate was concentrated, deionized water was added, and the pH was adjusted to 8-10. The mixture was extracted three times with 50 mL of dichloromethane, and the organic phase was dried. Finally, the mixture was concentrated by rotary evaporation, and the crude product was purified by column chromatography using dichloromethane / triethylamine (v / v ratio 100:1) as the eluent to obtain M5 (8.8 g, 90% yield). M4 was characterized by 1H NMR spectroscopy as follows: 1 H NMR (500 MHz, CDCl3): δ 6.60–6.30 (s, 1H), 3.85–3.69 (m, 1H), 3.02–2.90 (m, 2H), 2.67–2.22 (m, 4H), 1.95–1.35 (m, 12H).

[0047] S2: The difference from step S2 in Example 1 is that monomer M1 is replaced with monomer M5. The rest of the preparation methods and conditions are the same as in S2 in Example 1, and PM5 is obtained.

[0048] S3: The difference from step S3 in Example 1 is that monomer PM1 is replaced with monomer PM5. The rest of the preparation methods and conditions are the same as in S3 in Example 1, resulting in P8.

[0049] Example 12. S1: Aminocaprolactam (6.4 g, 0.05 mol) was dissolved in 200 mL of acetonitrile, potassium carbonate (4.15 g, 0.03 mol) was added, and the mixture was stirred evenly at room temperature. Then, 2-bromopropane (7.38 g, 0.06 mol) was added, and the mixture was heated under reflux at 85 °C for 10 h. After the reaction was completed, the filtrate was concentrated, deionized water was added, and the pH was adjusted to 8-10. The mixture was extracted three times with 50 mL of dichloromethane, and the organic phase was dried. Finally, the mixture was concentrated by rotary evaporation, and the crude product was purified by column chromatography using dichloromethane / triethylamine (volume ratio 100:1) as the eluent to obtain the intermediate (6.5 g, yield 76%). 6.5 g of the intermediate (0.038 mol) was dissolved in 200 mL of acetonitrile, and potassium carbonate (4.15 g, 0.03 mol) was added. The mixture was stirred thoroughly at room temperature, and then n-propyl bromide (7.38 g, 0.06 mol) was added. The mixture was heated under reflux at 85 °C for 10 h. After the reaction was complete, the filtrate was concentrated, deionized water was added, and the pH was adjusted to 8–10. The mixture was extracted three times with 50 mL of dichloromethane, and the organic phase was dried. Finally, the mixture was concentrated by rotary evaporation, and the crude product was purified by column chromatography using dichloromethane / triethylamine (v / v) as the eluent to obtain M6 (7.9 g, 97% yield). The structure of M6 was characterized by 1H NMR spectroscopy as follows: 1 H NMR (500 MHz, CDCl3): δ 6.02–5.89 (s, 1H), 3.57–3.52 (m, 1H), 3.48–3.37 (m, 1H), 3.15–3.02 (m, 2H), 2.66–2.54 (m, 2H), 1.97–1.35 (m, 8H), 1.06–0.94(dd, 6H), 0.85–0.73(t, 3H).

[0050] S2: The difference from step S2 in Example 1 is that monomer M1 is replaced with monomer M6, while the rest of the preparation methods and conditions are the same as in S2 in Example 1, to obtain PM6.

[0051] S3: The difference from step S3 in Example 1 is that monomer PM1 is replaced with monomer PM6. The rest of the preparation methods and conditions are the same as in S3 in Example 1, resulting in P9.

[0052] Example 13. S1: Aminocaprolactam (6.4 g, 0.05 mol) was dissolved in 200 mL of acetonitrile, and potassium carbonate (8.29 g, 0.06 mol) was added and stirred evenly at room temperature. Then, 3-bromopropene (14.52 g, 0.12 mol) was added, and the mixture was heated under reflux at 85 °C for 10 h. After the reaction was completed, the filtrate was concentrated, deionized water was added, and the pH was adjusted to 8-10. The mixture was extracted three times with 50 mL of dichloromethane, and the organic phase was dried. Finally, the mixture was concentrated by rotary evaporation, and the crude product was purified by column chromatography using dichloromethane / triethylamine (volume ratio 100:1) as the eluent to obtain M7 (7.2 g, yield 69%). The structure of M7 was characterized by 1H NMR spectroscopy as follows: 1 H NMR (500 MHz, CDCl3): δ 6.15–5.98 (s, 1H), 5.90–5.75 (m, 2H), 5.23–5.03 (m, 4H), 3.61–3.49 (m, 1H), 3.47–3.03 (m, 6H), 2.04–1.38 (m, 6H).

[0053] S2: The difference from step S2 in Example 1 is that monomer M1 is replaced with monomer M7. The rest of the preparation methods and conditions are the same as in S2 in Example 1, and PM7 is obtained.

[0054] S3: The difference from step S3 in Example 1 is that monomer PM1 is replaced with monomer PM7. The rest of the preparation methods and conditions are the same as in S3 in Example 1, and P10 is obtained.

[0055] Example 14. S1: Aminocaprolactam (6.4 g, 0.05 mol) was dissolved in 200 mL of acetonitrile, and potassium carbonate (8.29 g, 0.06 mol) was added and stirred evenly at room temperature. Then, 1-bromobutane (16.44 g, 0.12 mol) was added, and the mixture was heated under reflux at 85 °C for 10 h. After the reaction was completed, the filtrate was concentrated, deionized water was added, and the pH was adjusted to 8-10. The mixture was extracted three times with 50 mL of dichloromethane, and the organic phase was dried. Finally, the mixture was concentrated by rotary evaporation, and the crude product was purified by column chromatography using dichloromethane / triethylamine (volume ratio 100:1) as the eluent to obtain M8 (9.3 g, yield 78%). The structure of M8 was characterized by 1H NMR spectroscopy as follows: 1 H NMR (500 MHz, CDCl3): δ 6.14–5.98 (s, 1H), 3.47–3.29 (m, 2H), 2.72–2.52 (m, 4H), 1.99–1.17 (m,14H), 0.92–0.81 (t, 6H).

[0056] S2: The difference from step S2 in Example 1 is that monomer M1 is replaced with monomer M8. The rest of the preparation methods and conditions are the same as in S2 in Example 1, and PM8 is obtained.

[0057] S3: The difference from step S3 in Example 1 is that monomer PM1 is replaced with monomer PM8. The rest of the preparation methods and conditions are the same as in S3 in Example 1, resulting in P11.

[0058] Example 15. S1: Aminocaprolactam (6.4 g, 0.05 mol) was dissolved in 200 mL of acetonitrile, and potassium carbonate (8.29 g, 0.06 mol) was added and stirred evenly at room temperature. Then, 1-bromooctane (23.18 g, 0.12 mol) was added, and the mixture was heated under reflux at 85 °C for 10 h. After the reaction was completed, the filtrate was concentrated, deionized water was added, and the pH was adjusted to 8-10. The mixture was extracted three times with 50 mL of dichloromethane, and the organic phase was dried. Finally, the mixture was concentrated by rotary evaporation, and the crude product was purified by column chromatography using dichloromethane / triethylamine (v / v ratio 100:1) as the eluent to obtain M9 (14.1 g, yield 80%). The structure of M9 was characterized by 1H NMR spectroscopy as follows: 1 H NMR (500 MHz, CDCl3): δ 6.00–5.87 (s, 1H), 3.47–3.32 (m, 2H), 3.14–3.04 (m, 1H), 2.00–1.13 (m, 30H), 0.90–0.79 (t, 6H).

[0059] S2: The difference from step S2 in Example 1 is that monomer M1 is replaced with monomer M9. The rest of the preparation methods and conditions are the same as in S2 in Example 1, and PM9 is obtained.

[0060] S3: The difference from step S3 in Example 1 is that monomer PM1 is replaced with monomer PM9. The rest of the preparation methods and conditions are the same as in S3 in Example 1, resulting in P12.

[0061] Antibacterial performance test: The antibacterial efficacy was tested according to the method of National Medical Products Administration standard YY / T 0688.1-2023, and the incubation time was adjusted according to the actual situation. The specific operation is as follows: The nylon material prepared in Examples 1-15 above was serially diluted in Mueller-Hinton (MH) medium to a concentration of 12.5-200 μg / mL using the 2-fold dilution method. 100 μL was added to each well of a 96-well plate, followed by 100 μL of the prepared bacterial solution. The well plate was placed at 37℃ and shaken at 150 r / min for 9 h. After incubation, the optical density (OD) value at a wavelength of 600 nm was measured. MH medium without nylon material was used as a positive control group, and MH medium without bacterial inoculation was used as a blank control group. The bacteria used for detection were Escherichia coli (E. coli) ATCC25922 and Staphylococcus aureus (S. aureus) ATCC25923. The test results are shown in Table 1. As can be seen from the table, the nylon materials prepared in Examples 1-15 of this invention all exhibited inhibition rates of over 90% against both *Escherichia coli* and *Staphylococcus aureus*. The minimum inhibitory concentration (MIC) against *Escherichia coli* was as low as 25 μg / mL, and against *Staphylococcus aureus* as low as 12.5 μg / mL. This demonstrates that the nylon materials provided by this invention possess excellent antibacterial activity and effectively exert their antibacterial effect, laying the foundation for the preparation of antibacterial materials for common pathogenic bacteria with broad-spectrum antibacterial activity.

[0062] Biocompatibility testing: The nylon materials prepared in Examples 1-15 were serially diluted to concentrations of 50-200 μg / mL in DMEM complete medium containing 10% fetal bovine serum and 1% antibiotic-antifungal solution using a 2-fold dilution method. Mouse fibroblasts (L929) were seeded at a density of 5000 cells per well in 96-well plates and cultured at 37°C in a 5% CO2 incubator for 24 h. Then, 100 μL of nylon material solutions of different concentrations were added to each well, and the cells were cultured for another 24 h. After retaining adherent cells, DMEM solution containing 10% CCK-8 (V / V) was added, and the cells were incubated at 37°C in the dark for 2 h. The OD value was then measured at 450 nm. DMEM complete medium without nylon material was used as a control group. The test results are shown in Table 1. As can be seen from Table 1, within the tested range of 25-100 μg / mL, the survival rate of L929 cells of the nylon material remained above 80%, showing low cytotoxicity, which proves that the nylon material prepared in this invention has good biosafety and application potential under in vitro experimental conditions.

[0063] Hemolytic performance test: A 4% fresh rabbit blood erythrocyte suspension was prepared. The nylon material prepared in Examples 1-15 was serially diluted in PBS buffer using a 2-fold dilution method to a concentration of 50-200 μg / mL, and then mixed with an equal volume of erythrocyte suspension. After incubating the mixed solution at 37℃ for 1 h, 100 μL of the supernatant was centrifuged and placed in a 96-well plate. The OD value at a wavelength of 540 nm was measured. Deionized water was used as a positive control, and PBS buffer without nylon material was used as a negative control. The test results are shown in Table 1. As can be seen from Table 1, the nylon material prepared in this invention did not cause significant erythrocyte hemolysis in the concentration range of 50-100 μg / mL, and its hemolysis rate was lower than the safety threshold (5%), showing good blood compatibility. This proves that the nylon material prepared in this invention has excellent blood compatibility, almost no damaging effect on the erythrocyte membrane, and will not induce serious hematological toxicity reactions, and can be used in the manufacture of medical devices.

[0064] Table 1

[0065] Tests to inhibit bacterial biofilm formation: The nylon material prepared in Examples 1-15 was diluted in MH medium to a concentration of 50-200 μg / mL. 100 μL was added to each well of a 96-well plate, followed by 100 μL of the prepared bacterial culture. After incubation at 37 °C for 24 h, the culture medium was carefully removed from the plate, and the plate was washed three times with PBS buffer. 200 μL of 0.1% crystal violet staining solution was added, and the plate was incubated in the dark for 0.5 h. The staining solution was carefully removed, and the plate was washed three times with PBS buffer. 200 μL of 95% ethanol was added to dissolve the remaining crystal violet at room temperature for 1 h, and the OD value at 595 nm was measured. MH medium without nylon material was used as a positive control, and MH medium without bacterial inoculation was used as a blank control. The bacteria used for testing were *Escherichia coli* (E. coli) ATCC25922 and *Staphylococcus aureus* (S. aureus) ATCC25923. The test results are shown in Table 2. As can be seen from Table 2, the nylon material prepared in this invention exhibited a significant inhibitory effect on biofilm formation of both typical pathogenic bacteria at different concentrations, with inhibition rates all greater than 50%. This demonstrates that the nylon material provided by this invention shows a significant inhibitory effect on bacterial biofilm formation, further proving its application potential in the field of biomedical materials for inhibiting bacterial adhesion.

[0066] Test to remove mature bacterial biofilm: Add 200 μL of the prepared bacterial culture to each well of a 96-well plate. Incubate at 37°C for 24 h. Carefully remove the supernatant, then add 200 μL of the nylon material solution (25-100 μg / mL) and transfer to a 37°C incubator for another 24 h. After this, carefully remove the culture medium from the wells and wash three times with PBS buffer. Add 200 μL of 0.1% crystal violet staining solution, incubate in the dark for 0.5 h, then carefully remove the staining solution and wash three times with PBS buffer. Add 200 μL of 95% ethanol to dissolve the remaining crystal violet at room temperature for 1 h, and then measure the OD value at 595 nm. Use MH medium without nylon material as a positive control and MH medium without bacterial inoculation as a blank control. The bacteria used for testing were *Escherichia coli* (E. coli) ATCC25922 and *Staphylococcus aureus* (S. aureus) ATCC25923. The test results are shown in Table 2. As can be seen from Table 2, the nylon material prepared in this invention exhibits a significant removal effect on established mature biofilms, with a removal rate exceeding 50%. This demonstrates that the nylon material provided by this invention exhibits broad-spectrum and stable activity in the removal experiment of mature biofilms, and can be applied to the preparation of antibacterial and antifouling materials such as surface treatment materials for biofilm formation.

[0067] Temperature sensitivity performance test: The lowest eutectic temperature (LCST) of the polymer was determined by measuring the transmittance of nylon materials to 500 nm light at different temperatures. A 15 mg / mL aqueous solution of the aforementioned nylon material was prepared, with pure water as a reference. Heating and cooling were performed at a rate of 2 °C / min, within a temperature range of 20-50 °C. The test results are shown in Table 2. Table 2 shows that the LCST value of P1-25% nylon material is 32 ± 0.5 °C, close to the physiological temperature range of the human body. This indicates that this type of material can undergo reversible phase separation and aggregation under small temperature changes, exhibiting good temperature response sensitivity and potential biomedical application value. The LCST value of P1-50% nylon material is 80 ± 0.5 °C, much higher than the normal physiological ambient temperature, indicating high solution stability under daily use conditions, resistance to phase separation reactions, and greater suitability for high-temperature environments or applications requiring special functional materials. This invention demonstrates that the nylon material provided by this invention can exhibit adjustable temperature-sensitive response characteristics in different temperature ranges through structural regulation. It can meet the temperature-sensitive requirements under near-physiological temperature conditions and also cover application scenarios under high-temperature stable environments. This further reflects the diversity and applicability of nylon material design and can be applied to the preparation of temperature-responsive smart materials, temperature sensing, and intelligent control materials.

[0068] Table 2

[0069] In summary, this invention utilizes aminocaprolactam synthesized from bio-based lysine via cyclization as a raw material to develop a fully bio-based nylon material, completely eliminating the use of petroleum-based raw materials. Its bio-based content can reach 100%, achieving a multi-functional synergistic effect including antibacterial properties, biocompatibility, antibacterial biofilm properties, and temperature sensitivity. The functionality of the nylon material can be controlled by altering the side-chain structure, enabling customized production and expanding its broad application prospects in medical consumables, functional fibers, environmental purification, and smart materials.

[0070] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0071] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fully bio-based multifunctional antibacterial nylon material, characterized in that, The structural formula of the fully bio-based multifunctional antibacterial nylon material is shown in formula (Ⅰ) below: Equation (I); In the formula, R1 group and R2 group are straight-chain or branched C1 groups, respectively. 1-24 Aliphatic hydrocarbon group, substituted or unsubstituted C 3-12 Alicyclic hydrocarbon group, substituted or unsubstituted C 6-18 aryl, substituted or unsubstituted C 7-30 Any of the aralkyl groups, or the R1 and R2 groups on the same nitrogen atom together with the attached N atom to form a 5- to 7-membered saturated / or unsaturated heterocycle; The R3 group is hydrogen, a straight-chain or branched C group. 1-24 Aliphatic hydrocarbon group, substituted or unsubstituted C 3-12 Alicyclic hydrocarbon group, substituted or unsubstituted C 6-18 aryl, substituted or unsubstituted C 7-30 Any one of the aralkyl groups; X is any one of chloride, bromine, iodine, nitrate, bisulfate, bicarbonate, sulfonate, acetate, trifluoroacetate, and trifluoromethanesulfonate. m and n are the molar ratios of the corresponding repeating units to the total repeating units, respectively; where 0≤m≤1, 0≤n≤1, and m+n=1; the total number of each repeating unit ranges from 10 to 2500.

2. A method for preparing the all-bio-based multifunctional antibacterial nylon material as described in claim 1, characterized in that, Includes the following steps: S1: Reaction of aminocaprolactam solution with the corresponding aldehyde / carboxylic acid / haloalkane, followed by purification, yields cyclic lysine-derived monomer M; S2: Cyclic lysine-derived monomer M, initiator, and catalyst are mixed, heated, and reacted. After purification, nylon material PM is obtained. S3: The nylon PM solution was subjected to a quaternization reaction with an alkyl halide, and after purification, the fully bio-based multifunctional antibacterial nylon material P was obtained.

3. The method for preparing the all-bio-based multifunctional antibacterial nylon material according to claim 2, characterized in that, The corresponding aldehydes / carboxylic acids / haloalkanes mentioned in S1 are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, benzyl chloride, and monoiodocarbon. 1～30 Alkanes, monobrominated C 1～30 Alkanes, diiodocarbons 2～30 Alkanes, dibromoC 2～30 The aminocaprolactam solution contains one or more of the following: alkanes and allyl bromides; the concentration of the aminocaprolactam solution is 0.1–1.0 mol / L; the solvent in the aminocaprolactam solution is any one of acetonitrile, methanol, ethanol, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, dimethyl sulfoxide, N,N-dimethylformamide, chloroform, and carbon tetrachloride; the structure of the cyclic lysine-derived monomer M is shown in formula (II) below. Formula (II).

4. The method for preparing the all-bio-based multifunctional antibacterial nylon material according to claim 2, characterized in that, The reaction temperature in S1 is 20–100 °C, and the reaction time is 12 h; the molar ratio of aminocaprolactam to the corresponding aldehyde / carboxylic acid / haloalkane is 1:2–4; the purification steps are as follows: filter the reaction product, distill under reduced pressure, dissolve, adjust the pH to 8–10, extract, combine the organic phases, distill under reduced pressure, and separate the residue by column chromatography to complete the purification.

5. The method for preparing the all-bio-based multifunctional antibacterial nylon material according to claim 3, characterized in that, When haloalkanes are used in S1, a base needs to be added for the reaction. The base is any one of sodium carbonate, potassium carbonate, cesium carbonate, sodium bicarbonate, sodium phosphate, potassium phosphate, sodium acetate, and sodium hydroxide. The ratio of aminocaprolactam to base is 1:1 to 5.

6. The method for preparing the all-bio-based multifunctional antibacterial nylon material according to claim 2, characterized in that, The initiator in S2 is any one of benzoyl-protected caprolactam, acetyl-protected caprolactam, and benzoyl-protected N,N-dimethylcaprolactam; the catalyst is any one of sodium hydride, calcium hydride, potassium hydride, sodium methoxide, sodium ethoxide, sodium benzyl alcohol, sodium benzyl mercaptan, potassium bis(trimethylsilyl)amino, lithium bis(trimethylsilyl)amino, ethyl magnesium bromide, phenyl magnesium bromide, vinyl magnesium bromide, and propyl magnesium bromide; the molar ratio of the cyclic lysine-derived monomer M, the initiator, and the catalyst is 5–100:1:

1.

7. The method for preparing the all-bio-based multifunctional antibacterial nylon material according to claim 2, characterized in that, The heating temperature in S2 is 80~180℃, and the reaction time is 1~48 h; the purification steps are: quenching the reaction product, precipitation, and drying.

8. The method for preparing the all-bio-based multifunctional antibacterial nylon material according to claim 2, characterized in that, The alkyl halide in S3 is any one of iodomethane, iodoethane, iodopropane, iodobutane, bromoethane, bromopropane, and bromobutane; the solvent in the nylon PM solution is any one of methanol, ethanol, propanol, acetonitrile, propionitrile, chloroform, carbon tetrachloride, and dimethyl sulfoxide; the temperature of the quaternization reaction is 25–100°C; the reaction time is 10–48 h; the purification step is: removing the precipitate by vacuum distillation of the reaction product and drying.

9. The application of a fully bio-based multifunctional antibacterial nylon material as described in claim 1 or a fully bio-based multifunctional antibacterial nylon material prepared by any one of claims 2-8, characterized in that, It is applied in the fields of antibacterial materials, biomedical materials, antibacterial biofilms, and temperature-sensitive materials.

10. The application of the all-bio-based multifunctional antibacterial nylon material according to claim 9, characterized in that, Applications include the preparation of antimicrobial materials for common pathogenic bacteria with broad-spectrum antimicrobial activity, the manufacture of biocompatible medical devices, the preparation of surface treatment materials that inhibit bacterial adhesion and biofilm formation, the preparation of temperature-responsive smart materials, and the preparation of temperature-sensing and intelligent control materials.

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