Modified polylysine, and preparation method therefor and use thereof

Abstract

The present disclosure relates to a modified polylysine, and a preparation method therefor and the use thereof. The modified polylysine of the present disclosure has good thermal stability and an adjustable branching degree and melting point, and is easy to dissolve; and same has low cytotoxicity and an antibacterial rate of more than 99%, and can be used in the biomedicine, ultraviolet protection, optical anti-counterfeiting, anti-static and other fields. In the present disclosure, a cyclic lysine monomer is in contact with a nylon monomer under an inert atmosphere to perform a polymerization reaction, so as to prepare a modified polylysine. In the polymerization reaction system, no anionic polymerization initiator is added, and the preparation method is simple, thereby effectively reducing the polymerization cost; and the polymerization reaction conditions are mild and efficient, thereby improving the utilization rate of the monomers, and avoiding the generation of insoluble gel substances, such that the impurity content of products is relatively low.

Description

Modified polylysine, its preparation method and application Technical Field

[0001] This disclosure relates to the field of functional materials technology, specifically to a modified polylysine and its preparation method and application. Background Technology

[0002] Amino acids are renewable compounds derived from biomass and are widely used in the food, feed, and pharmaceutical industries. However, the insufficient chemical and thermal stability of natural amino acids limits their application in functional materials. Similar to the reactivity of amino acids, petrochemical-derived compounds such as lactams, diamines, and diacids are the core monomers of the polyamide industry. These monomers exhibit excellent thermal stability, and the resulting polyamides possess good solvent and heat resistance, making them suitable for engineering plastics, synthetic fibers, barrier films, and high-performance elastomers. However, the molecular structures of these synthesized materials generally only contain alkylene groups, benzene rings, and amide groups, resulting in low reactivity and limited structural adjustment space. Therefore, their processing performance and functionality are limited, making it difficult to meet the emerging demands of application fields. In conclusion, this study aims to develop novel bio-based polyamide functional materials by copolymerizing bio-derived amino acid derivatives with petrochemical-derived polyamide monomers.

[0003] Currently, amino acid-derived bio-based polyamides are mainly prepared by anionic polymerization and can be used in the pharmaceutical field after quaternization modification. CN111116472 A discloses a quaternized poly(ε-lysine) derivative material prepared by anionic polymerization from a seven-membered cyclic lysine monomer; this polymer has a linear structure and features good water solubility, excellent bactericidal effect, and low biocidal concentration. CN115707727A discloses a quaternized polyamide material obtained by anionic ring-opening polymerization of cyclic lysine and caprolactam; this polymer also has a linear structure, exhibits broad-spectrum and highly efficient antibacterial effects, and long-lasting antibacterial activity. The polymerization reaction of the above-mentioned modified polylysine materials requires the use of anionic initiators and strict dehydration and deoxygenation; while the quaternization modification reaction needs to be carried out in a solvent. Due to the complexity of the preparation process and the high overall cost, there are still bottlenecks in the large-scale production of such materials. In addition, some quaternary ammonium salt compounds have been found to have biotoxicity. Therefore, novel bio-based polyamide products that balance antibacterial properties and biosafety, as well as their preparation technologies, still need further development. Summary of the Invention

[0004] The inventors of this invention have discovered that lysine-based monomers, such as aminocaprolactam, have a thermal stability temperature below 200°C and are prone to self-polymerization and isomerization; while the polymerization temperature of conventional polyamides is typically above 220°C. Due to the mismatch in polymerization rates and thermal stability between these two types of monomers, it is difficult to obtain copolymers with relatively uniform structures using existing technologies. Furthermore, those skilled in the art know that polylysine molecules contain "α-polymerization" and "ε-polymerization" structures, as well as linear and branched structures; these structural differences significantly affect the antibacterial properties, cytotoxicity, and other properties of the material. Therefore, improvements are desired to address these shortcomings.

[0005] The purpose of this disclosure is to provide a modified polylysine, its preparation method, and its applications. This modified polylysine exhibits good thermal stability, controllable molecular structure, adjustable melting point and solubility, and is easily processed. It can be applied in antibacterial materials, UV protection, optical anti-counterfeiting, and antistatic materials. In this invention, by optimizing the branched structure and "ε-polymerization" structure of the polylysine molecule, good antibacterial properties and low cytotoxicity can be achieved. The preparation method of the modified polylysine is simple, requires no catalyst such as anionic ring-opening polymerization catalyst, is resistant to water and oxygen, and is easy to implement. It enables stable and controllable copolymerization of lysine monomers and conventional polyamide monomers, and the resulting product has low insoluble matter and residual monomer content, allowing for large-scale production.

[0006] To achieve the above objectives, a first aspect of this disclosure provides a modified polylysine, wherein the modified polylysine comprises linear repeating units and lysine-branched repeating units; wherein:

[0007] 1) Based on the total amount of repeating units in modified polylysine, when the content of lysine repeating units is <4wt%, the molar content of lysine branched repeating units in the lysine repeating units is <20%, preferably >1% and <10%.

[0008] 2) Based on the total amount of repeating units in modified polylysine, when the content of lysine repeating units is ≥4wt% and ≤10wt%, the molar content of lysine branched repeating units in the lysine repeating units is <50%, preferably >0.10% and <40%; and

[0009] 3) Based on the total amount of repeating units in modified polylysine, when the content of lysine repeating units is >10wt%, the molar content of lysine branched repeating units in the lysine repeating units is <95%, preferably >40% and <90%.

[0010] In this invention, the branched repeating unit includes one or more of formulas (I) to (IV), and the linear repeating unit includes one or more of formulas (V) to (VI), wherein... Indicates a chemical bond;

[0011] Among them, R1 is selected from H and C. 1-20 Substituted or unsubstituted alkyl, C 3-20 Substituted or unsubstituted cycloalkyl, C 6-20 Substituted or unsubstituted aromatic groups, C 5-20 One or more of substituted or unsubstituted heteroaryl groups;

[0012] Each R2 is independently selected from C. 1-20 Substituted or unsubstituted alkylene, C 3-20 Substituted or unsubstituted cycloalkylene, C 6-20 Substituted or unsubstituted aromatic groups, C 5-20 One or more of the substituted or unsubstituted heteroaryl groups;

[0013] Among them, R3, R4, and R5 are each independently selected from C. 1-20 Substituted or unsubstituted alkylene, C 3-20 Substituted or unsubstituted cycloalkylene, C 6-20 Substituted or unsubstituted aromatic groups, C 5-20 One or more of the substituted or unsubstituted heteroaryl groups;

[0014] In this case, the substituents of R1, R2, R3, R4, and R5 are each independently selected from C. 1-10 alkyl, C 1-10 One or more of the alkoxy groups;

[0015] Preferably, the branched repeating unit includes one or more of formula (III) and formula (IV), and the linear repeating unit includes one or more of formula (V) and formula (VI); or preferably, the branched repeating unit includes one or more of formula (III) and formula (IV), and the linear repeating unit includes formula (V).

[0016] In some embodiments, preferably, the branched repeating unit includes one or more of formulas (III) and (IV), and more preferably, the branched repeating unit includes the branched repeating unit shown in formula (III).

[0017] In this invention, based on the total amount of lysine-based branched repeating units in the modified polylysine, the molar content of lysine-based branched repeating units in the ε-polymer form is 40%-80%.

[0018] In this invention, based on the total amount of repeating units in the modified polylysine, the molar content of lysine-based branched repeating units is 0.01-70%, preferably 10-65%.

[0019] In this invention, the content of lysine repeating units is 1 wt%-95 wt%, preferably 10 wt%-95 wt%, and more preferably 15 wt%-90 wt%, based on the total amount of repeating units in the modified polylysine.

[0020] In this invention, for the modified polylysine of this invention, the content of lysine-based repeating units is 15wt%-90wt% based on the total amount of repeating units in the modified polylysine; the proportion of lysine-based branched repeating units in the lysine-based repeating units is >50% and <90%; the molar content of ε-polymerized lysine-based branched repeating units is 40%-80% based on the total amount of lysine-based branched repeating units in the modified polylysine; and the branched repeating units include one or more of formulas (III) and (IV), and the linear repeating units include formula (V).

[0021] In this invention, the mass content of insoluble matter in the modified polylysine is <3%, preferably less than <1%, and more preferably less than <0.5%.

[0022] In this invention, the mass percentage of residual monomers in the modified polylysine is <15%.

[0023] In this invention, the degree of branching of the modified polylysine is 0.05-0.7, preferably 0.15-0.65.

[0024] In this invention, the modified polylysine has a relative viscosity of 1.2-5.0 at 25°C.

[0025] In this invention, the weight-average molecular weight of the modified polylysine is 10,000 to 150,000.

[0026] In this invention, the modified polylysine has a molecular weight distribution of 1.2-2.5.

[0027] In this invention, the hydrodynamic diameter of the modified polylysine is 50nm-1000nm, preferably 50nm-700nm.

[0028] In this invention, R1 is selected from H and C. 1-15 Substituted or unsubstituted alkyl, C 3-15 Substituted or unsubstituted cycloalkyl, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R1 selected from H, C 1-6 Substituted or unsubstituted alkyl, C 3-8 Substituted or unsubstituted cycloalkyl, C 6-10 Substituted or unsubstituted aromatic groups, C 5-10One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R1 is selected from C 1-5 alkyl, C 1-5 R1 is selected from one or more of the following alkoxy groups: H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted phenyl, substituted or unsubstituted furanyl, and wherein the substituent of R1 is selected from one or more of methyl, ethyl, propyl, butyl, ethoxy and propoxy.

[0029] In this invention, R2 is selected from C. 1-15 Substituted or unsubstituted alkylene, C 3-15 Substituted or unsubstituted cycloalkylene, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R2 selected from C 1-6 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups, C 5- 10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R2 is selected from C 1-5 alkyl, C 1-5 R2 is selected from one or more of the alkoxy groups; preferably, R2 is selected from one or more of the following: substituted or unsubstituted methylene, substituted or unsubstituted ethylene, substituted or unsubstituted propylene, substituted or unsubstituted butylene, substituted or unsubstituted pentylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, and substituted or unsubstituted furanylene, and wherein the substituent of R2 is selected from one or more of the following: methyl, ethyl, propyl, butyl, ethoxy, and propoxy.

[0030] In this invention, R3 is selected from C. 2-12 Substituted or unsubstituted alkylene, C 3-15 Substituted or unsubstituted cycloalkylene, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R3 selected from C 2-11 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups, C 5- 10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R3 is selected from C1-5 alkyl, C 1-5 One or more of the alkoxy groups; preferably, R3 is selected from one or more of ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, and undecylene, and wherein the substituents of R3 are selected from one or more of methyl, ethyl, propyl, and butyl.

[0031] In this invention, R4 and R5 are each independently selected from C. 1-18 Substituted or unsubstituted alkylene, C 3-18 Substituted or unsubstituted cycloalkylene, C 6-18 Substituted or unsubstituted aromatic groups and C 5-20 One or more of substituted or unsubstituted heteroaryl groups, preferably R4 and R5 each independently selected from C 1-12 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups and C 5-10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituents R4 and R5 are each independently selected from C 1-5 alkyl, C 1-5 One or more of the alkoxy groups; preferably, R4 and R5 are each independently selected from one or more of ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, substituted or unsubstituted furanylene, and wherein the substituents of R4 and R5 are each independently selected from one or more of methyl, ethyl, propyl and butyl.

[0032] To achieve the above objectives, a second aspect of this disclosure provides a method for preparing modified polylysine, the method comprising:

[0033] Modified polylysine was prepared by polymerizing cyclic lysine monomers with nylon monomers in an inert atmosphere in the presence of a reaction aid.

[0034] The reaction aid is selected from amino acids;

[0035] The nylon monomer includes one or more of lactam compounds and nylon salts;

[0036] The cyclic lysine monomer has the structure shown in formula (1), the lactam compound has the structure shown in formula (2), and the nylon salt has the structure shown in formula (3).

[0037] [+ H3NR5NH3 +- OOCR4COO - Equation (3),

[0038] Among them, one of L1 and L2 is H and the other is R1; or, one of L1 and L2 is -R2-R' and the other is R1; or, L1 and L2 are both -R2-R'.

[0039] Among them, R1 is selected from H and C. 1-20 Substituted or unsubstituted alkyl, C 3-20 Substituted or unsubstituted cycloalkyl, C 6-20 Substituted or unsubstituted aromatic groups, and C 5-20 Substituted or unsubstituted heteroaryl groups;

[0040] Each R2 is independently selected from C. 1-20 Substituted or unsubstituted alkylene, C 3-20 Substituted or unsubstituted cycloalkylene, C 6-20 Substituted or unsubstituted aromatic groups, and C 5-20 Substituted or unsubstituted heteroaryl groups;

[0041] Each R' is independently selected from carboxyl, amino, amide, hydroxyl, isocyanate, and aldehyde groups;

[0042] Among them, R3, R4, and R5 are each independently selected from C. 1-20 Substituted or unsubstituted alkylene, C 3-20 Substituted or unsubstituted cycloalkylene, C 6-20 Substituted or unsubstituted aromatic groups, and C 5- 20 Substituted or unsubstituted heteroaryl groups; and

[0043] In this case, the substituents of R1, R2, R3, R4, and R5 are each independently selected from C. 1-10 alkyl, C 1-5 One or more of the alkoxy groups.

[0044] In this invention, R1 is selected from H and C. 1-15 Substituted or unsubstituted alkyl, C 3-15 Substituted or unsubstituted cycloalkyl, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R1 selected from H, C 1-6 Substituted or unsubstituted alkyl, C 3-8 Substituted or unsubstituted cycloalkyl, C 6-10 Substituted or unsubstituted aromatic groups, C 5-10One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R1 is selected from C 1-5 alkyl, C 1-5 R1 is selected from one or more of the following alkoxy groups: H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted phenyl, substituted or unsubstituted furanyl, and wherein the substituent of R1 is selected from one or more of methyl, ethyl, propyl, butyl, ethoxy, and propoxy.

[0045] In this invention, R2 is selected from C. 1-15 Substituted or unsubstituted alkylene, C 3-15 Substituted or unsubstituted cycloalkylene, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R2 selected from C 1-6 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups, C 5- 10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R2 is selected from C 1-5 alkyl, C 1-5 R2 is selected from one or more of the alkoxy groups; preferably, R2 is selected from one or more of the following: substituted or unsubstituted methylene, substituted or unsubstituted ethylene, substituted or unsubstituted propylene, substituted or unsubstituted butylene, substituted or unsubstituted pentylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, and substituted or unsubstituted furanylene, and wherein the substituent of R2 is selected from one or more of the following: methyl, ethyl, propyl, butyl, ethoxy, and propoxy.

[0046] In this invention, R3 is selected from C. 2-12 Substituted or unsubstituted alkylene, C 3-15 Substituted or unsubstituted cycloalkylene, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R3 selected from C 2-11 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups, C 5- 10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R3 is selected from C1-5 alkyl and C 1-5 One or more of the alkoxy groups; preferably, R3 is selected from one or more of ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, and undecylene, and wherein the substituents of R3 are selected from one or more of methyl, ethyl, propyl, and butyl.

[0047] In this invention, R4 and R5 are each independently selected from C. 1-18 Substituted or unsubstituted alkylene, C 3-18 Substituted or unsubstituted cycloalkylene, C 6-18 Substituted or unsubstituted aromatic groups and C 5-20 One or more of substituted or unsubstituted heteroaryl groups, preferably R4 and R5 each independently selected from C 1-12 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups and C 5-10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituents R4 and R5 are each independently selected from C 1-5 alkyl, C 1-5 One or more of the alkoxy groups; preferably, R4 and R5 are each independently selected from one or more of ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, substituted or unsubstituted furanylene, and wherein the substituents of R4 and R5 are each independently selected from one or more of methyl, ethyl, propyl and butyl.

[0048] In this invention, the lactam compound can be C 4-15 The lactam is preferably selected from one or more of butyrolactam, valproic acid lactam, caprolactam, heptalactam, octyllactam, nonanolactam, decanolactam, undecanolactam, dodecalactam, and tridecalactam; more preferably, caprolactam.

[0049] In this invention, the nylon salt may be one or more selected from nylon 46 salt, nylon 4T salt, nylon 56 salt, nylon 5T salt, nylon 66 salt, nylon 6T salt, nylon 6I salt, nylon 610 salt, nylon 612 salt, nylon MXD6 salt, nylon 9T salt, nylon 910 salt, nylon 912 salt, nylon 1010 salt, nylon 10T salt, nylon 1012 salt, nylon 1212 salt, nylon 12T salt, nylon PACM6 salt, nylon PACMT salt, nylon PACMI salt, nylon MACMT salt, and nylon MACMI salt; preferably, the nylon salt is selected from one or more selected from nylon 66 salt, nylon 56 salt, nylon 6T salt, nylon MXD6 salt, nylon 9T salt, and nylon 10T salt; more preferably, the nylon salt is selected from one or more selected from nylon 66 salt, nylon 6T salt, and nylon MXD6 salt.

[0050] In some embodiments of the present invention, the cyclic lysine monomer may be selected from compounds of formula (1) in L1 and L2, where one is H and the other is R1; preferably, in the present invention, the cyclic lysine monomer may be selected from one or more of α-amino-ε-caprolactam, α-(N-methyl)amino-ε-caprolactam, α-(N-ethyl)amino-ε-caprolactam, α-(N-propyl)amino-ε-caprolactam, α-(N-butyl)amino-ε-caprolactam, and α-(N-benzyl)amino-ε-caprolactam. In the present invention, the proportion of the cyclic lysine monomer in the total monomer content may be 1wt%-95wt%, preferably 10wt%-95wt%, more preferably 15wt%-90wt%; and the mass ratio of the cyclic lysine monomer to the nylon monomer is 1:99-95:5, preferably 10:90-95:5, more preferably 15:85-90:10.

[0051] In this invention, the reaction auxiliary can be one or more selected from aminobutyric acid, aminovaleric acid, aminohexanoic acid, aminoheptanoic acid, aminooctanoic acid, and arginine, more preferably aminohexanoic acid. In this invention, the reaction auxiliary can account for 0.5-10% of the total mass of the reactants, preferably 2-6%.

[0052] In this invention, no anionic polymerization catalyst, water, or acid is added to the method.

[0053] In this invention, the inert atmosphere includes one or more of nitrogen, helium, and argon.

[0054] In this invention, the conditions for the polymerization reaction include: a polymerization temperature of 70-280℃, preferably 100-270℃, more preferably 140-260℃, and even more preferably 140-250℃; a time of 0.5-24h, preferably 4-14h; and a pressure of 0-1.5MPa, preferably 0.2-0.6MPa.

[0055] In this invention, the polymerization can be carried out under stirring conditions. The stirring rate can be 20-400 r / min, preferably 50-150 r / min.

[0056] In some embodiments of the present invention, the polymerization reaction may include a first polymerization stage and a second polymerization stage; the conditions of the first polymerization stage include a temperature of 100-210°C, preferably 140-200°C, and a time of 1-8 hours, preferably 2-4 hours; and the conditions of the second polymerization stage include a temperature of 200-280°C, preferably 200-260°C, and a time of 1-9 hours, preferably 1-4 hours.

[0057] In some embodiments of the present invention, the method further includes: after the polymerization reaction has proceeded, depressurizing the reaction system and allowing the reaction system to continue reacting under a second pressure; wherein the second pressure is 0.0 to -0.1 MPa, preferably 0.0 to -0.09 MPa, and the reaction time under the second pressure is 0.5 to 16 h, preferably 0.5 to 10 h.

[0058] In some preferred embodiments, the modified polylysine prepared by the method of the second aspect of this disclosure is the modified polylysine described in the first aspect of this invention.

[0059] This disclosure provides a composition comprising the modified polylysine described in the first aspect of the invention; preferably, the composition is in the form of a dispersion, powder, wire, fiber, film, coating, sheet, plate, irregular material, porous material, or gel material.

[0060] This fourth aspect of the disclosure provides the use of the modified polylysine described in the first aspect of the disclosure as an antibacterial agent.

[0061] In some embodiments of the present invention, the modified polylysine has an antibacterial rate of more than 90% against Escherichia coli, preferably more than 99%, and more preferably more than 99.9%.

[0062] In some embodiments of the present invention, the modified polylysine has an antibacterial rate of 90% or more against Staphylococcus aureus, preferably 99% or more, and more preferably 99.9% or more.

[0063] In some embodiments of the present invention, the survival rate of NIH 3T3 cells is higher than 50% in a neutral phosphate buffer of the modified polylysine at a concentration of 1.5 mg / ml.

[0064] In some embodiments of this invention, the modified polylysine is used as an antibacterial agent in solid form; or

[0065] The modified polylysine is used as an antibacterial agent after being dissolved in a solvent; preferably, the solvent is selected from one or more of water, alcohols, esters, ethers, furans, ketones and hydrocarbon solvents, and more preferably one or more of water, ethanol, ethyl acetate, tetrahydrofuran, acetone and cyclohexane.

[0066] The fifth aspect of this disclosure provides the application of the modified polylysine described in the first aspect of this disclosure in optical materials; preferably, the modified polylysine has a transmittance of less than 60% at a 300 nm UV wavelength; and / or the fluorescence excitation wavelength of the modified polylysine is between 200-650 nm and the emission wavelength is between 400-800 nm.

[0067] The sixth aspect of this disclosure provides the application of the first aspect of this disclosure in antistatic agents, adhesives, sealants, water treatment agents, drug carriers, cement water-reducing agents, inks, fabric finishing agents, or fiber colorants.

[0068] Through the above embodiments, this disclosure prepares modified polylysine with a branched structure by reacting a mixture of lactam compounds and / or nylon salts with cyclic lysine derivatives. This invention eliminates the need for anionic polymerization initiators, simplifies the preparation method, and effectively reduces polymerization costs. The modified polylysine of this disclosure exhibits good thermal stability, adjustable branching degree, and controllable melting point, making it suitable for use in antibacterial materials, UV protection, optical anti-counterfeiting, and antistatic materials.

[0069] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0070] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0071] Figure 1 is the infrared spectrum of the products obtained in Examples 1-5 and Comparative Examples 1-3 of this disclosure.

[0072] Figure 2 is the 1H NMR spectrum of the products obtained in Examples 1-5 of this disclosure.

[0073] Figure 3 is a photograph of the ethanol dispersions of the products obtained in Example 13, Comparative Example 6 and Comparative Example 7 under natural light conditions (from left to right).

[0074] Figure 4 is a GPC diagram of the product obtained in Example 29.

[0075] Figure 5 shows the hydrodynamic diameter test results of the product obtained in Example 17.

[0076] Figure 6 is a thermogravimetric curve of the products obtained in Examples 1 and 29.

[0077] Figure 7 shows the UV-Vis spectrum of the products obtained in Examples 3-5 when they were made into a 200 μm thin film.

[0078] Figure 8 is a two-dimensional fluorescence spectrum of the product obtained in Example 3.

[0079] Figure 9 shows the cytotoxicity test results of the products obtained in Examples 16, 18 and 19. Detailed Implementation

[0080] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0081] The first aspect of this disclosure provides a modified polylysine, wherein the modified polylysine comprises linear repeating units and lysine-branched repeating units; wherein:

[0082] 1) Based on the total amount of repeating units in modified polylysine, when the content of lysine repeating units is <4wt%, the molar content of lysine branched repeating units in the lysine repeating units is <10%, preferably >1% and <10%.

[0083] 2) Based on the total amount of repeating units in the modified polylysine, when the content of lysine repeating units is ≥4wt% and ≤10wt%, the molar content of lysine branched repeating units in the lysine repeating units is <50%, preferably >0.10% and <40%; and

[0084] 3) Based on the total amount of repeating units in the modified polylysine, when the content of lysine repeating units is >10wt%, the proportion of lysine branched repeating units in the lysine repeating units is <95%, preferably >40% and <90%, more preferably >50% and <90%.

[0085] In this invention, when the content of lysine repeating units is <4 wt% based on the total amount of repeating units in the modified polylysine, the molar content of lysine branched repeating units in the lysine repeating units can be 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 9.6%, 9.7%, 9.8%, 9.9%, or any range of two of the above values, for example, 1.1%-9.8%.

[0086] In this invention, when the content of lysine-based repeating units is ≥4 wt% and ≤10 wt% based on the total amount of repeating units in the modified polylysine, the molar content of lysine-based branched repeating units in the lysine-based repeating units can be 0.15%, 0.2%, 0.5%, 0.8%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, or any range of two of the above values, for example, 0.2%-39%.

[0087] In this invention, when the content of lysine repeating units is >10wt% based on the total amount of repeating units in the modified polylysine, the proportion of lysine branched repeating units in the lysine repeating units can be 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 65%, 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, or any range of two of the above values, for example, 51%-89%.

[0088] In some preferred embodiments of the present invention, the content of lysine repeating units in the modified polylysine is at least 10 wt%, for example, 10 wt% to 90 wt%, based on the total amount of repeating units in the modified polylysine.

[0089] In this invention, the molar ratio of lysine-branched repeating units is based on the total amount of lysine repeating units in the modified polylysine. 1 H-NMR spectroscopy measurements were performed, and the integral area of ​​the characteristic peak corresponding to the branched repeating unit of lysine group was calculated.

[0090] According to the embodiments of the present invention, when the molar content of the branched repeating unit of lysine in the repeating unit of lysine is within the preferred range, the corresponding modified polylysine has a more uniform molecular structure, a higher proportion of "ε-polymer" structure, a larger molecular weight, and a lower content of insoluble matter, residual monomers and other colored impurities, which is beneficial to reduce cytotoxicity and achieve better optical and antibacterial application effects.

[0091] In this invention, the lysine-branched repeating unit may include one or more of formulas (I)-(IV), and the linear repeating unit may include one or more of formulas (V)-(VI).

[0092] In the formula Indicates a chemical bond;

[0093] Among them, R1 is selected from H and C. 1-20 Substituted or unsubstituted alkyl, C 3-20 Substituted or unsubstituted cycloalkyl, C 6-20 Substituted or unsubstituted aromatic groups, C 5-20 One or more of substituted or unsubstituted heteroaryl groups;

[0094] Each R2 is independently selected from C. 1-20 Substituted or unsubstituted alkylene, C 3-20 Substituted or unsubstituted cycloalkylene, C 6-20 Substituted or unsubstituted aromatic groups, C 5-20 One or more of the substituted or unsubstituted heteroaryl groups;

[0095] Among them, R3, R4, and R5 are each independently selected from C. 1-20 Substituted or unsubstituted alkylene, C 3-20 Substituted or unsubstituted cycloalkylene, C 6-20 Substituted or unsubstituted aromatic groups, C 5-20 One or more of the substituted or unsubstituted heteroaryl groups;

[0096] In this case, the substituents of R1, R2, R3, R4, and R5 are each independently selected from C. 1-10 alkyl, C 1-10 One or more of the alkoxy groups.

[0097] In some embodiments of the present invention, preferably, the branched repeating unit includes one or more of formulas (III) and (IV), and the linear repeating unit includes one or more of formulas (V) and (VI).

[0098] In some embodiments of the present invention, preferably, the branched repeating unit comprises one or more of formulas (III) and (IV), and the linear repeating unit comprises formula (V). In such embodiments, R1 may be selected from H, substituted or unsubstituted C. 1-5 Alkyl and C 6-10 The substituted or unsubstituted aromatic group; more preferably, R1 is selected from H, methyl, ethyl, propyl, butyl, benzyl and phenyl, and R3 is selected from one or more of ethylidene, propylidene, butylidene, pentylidene, hexylidene, heptylidene, octylidene, nonylidene, decylidene, preferably butylidene.

[0099] In some embodiments of this invention, R1 is selected from H and C. 1-15 Substituted or unsubstituted alkyl, C 3-15 Substituted or unsubstituted cycloalkyl, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R1 selected from H, C 1-6 Substituted or unsubstituted alkyl, C 3-8 Substituted or unsubstituted cycloalkyl, C 6-10 Substituted or unsubstituted aromatic groups, C 5-10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R1 is selected from C 1-5 alkyl, C 1-5 R1 is selected from one or more of the following alkoxy groups: H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted phenyl, substituted or unsubstituted furanyl, and wherein the substituent of R1 is selected from one or more of methyl, ethyl, propyl, butyl, ethoxy and propoxy.

[0100] In some embodiments of this invention, R1 is selected from H, substituted or unsubstituted C. 1- 5-alkyl and C 6-10 A substituted or unsubstituted aromatic group; more preferably, R1 is selected from H, methyl, ethyl, propyl, butyl, benzyl and phenyl.

[0101] In some embodiments of this invention, R2 is selected from C. 1-15 Substituted or unsubstituted alkylene, C 3-15 Substituted or unsubstituted cycloalkylene, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R2 selected from C 1-6Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups, C 5-10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R2 is selected from C 1-5 alkyl, C 1-5 R2 is selected from one or more of the alkoxy groups; preferably, R2 is selected from one or more of the following: substituted or unsubstituted methylene, substituted or unsubstituted ethylene, substituted or unsubstituted propylene, substituted or unsubstituted butylene, substituted or unsubstituted pentylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, and substituted or unsubstituted furanylene, and wherein the substituent of R2 is selected from one or more of the following: methyl, ethyl, propyl, butyl, ethoxy, and propoxy.

[0102] In some embodiments of this invention, R3 is selected from C. 2-12 Substituted or unsubstituted alkylene, C 3-15 Substituted or unsubstituted cycloalkylene, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R3 selected from C 2-11 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups, C 5-10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R3 is selected from C 1-5 alkyl, C 1-5 One or more of the alkoxy groups; preferably, R3 is selected from one or more of ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, and undecylene, and wherein the substituents of R3 are selected from one or more of methyl, ethyl, propyl, and butyl.

[0103] In some embodiments of this invention, R4 and R5 are each independently selected from C. 1-18 Substituted or unsubstituted alkylene, C 3-18 Substituted or unsubstituted cycloalkylene, C 6-18 Substituted or unsubstituted aromatic groups and C 5-20 One or more of substituted or unsubstituted heteroaryl groups, preferably R4 and R5 each independently selected from C 1-12 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups and C 5-10One or more of substituted or unsubstituted heteroaryl groups, wherein the substituents R4 and R5 are each independently selected from C 1-5 alkyl, C 1-5 One or more of the alkoxy groups; preferably, R4 and R5 are each independently selected from one or more of ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, substituted or unsubstituted furanylene, and wherein the substituents of R4 and R5 are each independently selected from one or more of methyl, ethyl, propyl and butyl.

[0104] In some embodiments, preferably, the branched repeating unit includes one or more of formulas (III) and (IV), and more preferably, the branched repeating unit includes the branched repeating unit shown in formula (III).

[0105] In this invention, the modified lysine is a polymerization product that has not been separated and / or purified, that is, a product obtained directly after the polymerization reaction without subsequent separation and / or purification.

[0106] The modified polylysine of the present invention contains little, substantially no, or no insoluble matter. In some embodiments, the mass content of insoluble matter in the modified polylysine of the present invention is <3%, preferably less than <1%, more preferably less than <0.5%. In the present invention, "insoluble matter" refers to solid or gel substances that cannot be dissolved in water or organic solvents.

[0107] In this invention, the modified polylysine contains less residual monomer. In some embodiments, the mass content of residual monomer in the modified polylysine is <15%.

[0108] In some embodiments of the present invention, the molar content of lysine-based branched repeating units can be 0.01-70%, preferably 10-65%, based on the total amount of repeating units in the modified polylysine. In the present invention, the molar content of lysine-based branched repeating units can be 0.01%, 0.1%, 0.2%, 0.5%, 0.8%, 1%, 2%, 4%, 8%, 12%, 16%, 20%, 24%, 28%, 32%, 36%, 40%, 44%, 48%, 52%, 56%, 60%, 64%, 68%, 70%, or any range of two of the above values, for example, 5-65%.

[0109] In this invention, the molar ratio / content of lysine-based branched repeating units is determined based on the total amount of repeating units in the modified polylysine. 1H-NMR spectroscopy measurements were performed, and the integral area of ​​the characteristic peak corresponding to the branched repeating unit of lysine group was calculated.

[0110] In some embodiments of the present invention, the molar content of ε-polymerized lysine-based branched repeating units in the modified polylysine can be 40%-80% based on the total amount of lysine-based branched repeating units in the modified polylysine. In the present invention, the molar content of ε-polymerized lysine-based branched repeating units in the modified polylysine can be 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 77%, 80%, or any range of two of the above values.

[0111] In this invention, "ε-polymerization" has the meaning commonly understood in the art as disclosed in patent CN119522157A. Specifically, in this invention, "ε-polymerization" refers to a bonding mode similar to the repeating units in an ε-polylysine or nylon 6 molecular chain; "α-polymerization" refers to a bonding mode similar to the repeating units in an α-polylysine molecular chain.

[0112] In this invention, the molar content of lysine-based branched repeating units in ε-polymerized polylysine is determined based on the amount of lysine-based branched repeating units in the modified polylysine. 1 H-NMR spectroscopy measurements were performed, and the integral area of ​​the characteristic peak corresponding to the branched repeating unit of lysine in the form of "ε-polymerization" was calculated.

[0113] In this invention, for the modified polylysine of this invention, based on the total amount of repeating units in the modified polylysine, the content of lysine repeating units can be 1wt%-95wt%, preferably 10wt%-95wt%, more preferably 15wt%-90wt%. In this invention, for the modified polylysine of this invention, based on the total amount of repeating units in the modified polylysine, the content of lysine repeating units can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 23wt%, 25wt%, 27wt%, 30wt%, 33wt%, 35wt%, 37wt%, 40wt%, 43wt%. The content / proportion of lysine repeating units can be calculated based on the monomer feed ratio, in the form of wt%, 45wt%, 47wt%, 50wt%, 53wt%, 55wt%, 57wt%, 60wt%, 63wt%, 65wt%, 67wt%, 70wt%, 73wt%, 75wt%, 77wt%, 80wt%, 81wt%, 82wt%, 83wt%, 84wt%, 85wt%, 86wt%, 87wt%, 88wt%, 89wt%, 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, or any range of two of the above values, for example, 16wt%-88wt%. In this invention, the content / proportion of lysine repeating units can be calculated based on the monomer feed ratio, according to the total amount of repeating units in the modified polylysine. In some embodiments, for the modified polylysine of the present invention, the content of lysine repeating units can be 20wt%-90wt%, 20wt%-80wt%, 20wt%-70wt%, 20wt%-60wt%, 20wt%-50wt%, 30wt%-90wt%, 30wt%-80wt%, 30wt%-70wt%, 30wt%-60wt%, 30wt%-50wt%, 40wt%-90wt%, 40wt%-80wt%, 40wt%-70wt%, 40wt%-60wt%, or 40wt%-50wt%, based on the total amount of repeating units in the modified polylysine.

[0114] In this invention, according to some preferred embodiments, for the modified polylysine of this invention, the content of lysine-based repeating units is 15wt%-90wt% based on the total amount of repeating units in the modified polylysine; wherein the proportion of lysine-based branched repeating units in the lysine-based repeating units is >50% and <90%; wherein the molar content of ε-polymerized lysine-based branched repeating units is 40%-80% based on the total amount of lysine-based branched repeating units in the modified polylysine; and wherein the branched repeating units include one or more of formula (III) and formula (IV), and the linear repeating units include one or more of formula (V) and formula (VI).

[0115] In some embodiments of the present invention, the linear repeating unit may further include one or more of the following linear repeating units: -HN(CH2)4CH(N(R1)(R2R'))CO-, -R2(R1)NCH((CH2)4NH2)CO-, -HN(CH2)4CH(N(R2R')(R2R'))CO-, -R2((R2R'))NCH((CH2)4NH2)CO-, -HN(CH2)4CH(NHR1)CO-, and -(R1)NCH((CH2)4NH2)CO-; preferably, the linear repeating unit further includes one or two of the following linear repeating units: -HN(CH2)4CH(NHR1)CO- and -(R1)NCH((CH2)4NH2)CO-. In these embodiments, R1, R2, and R' are each as described above. As understood by those skilled in the art, the above linear repeating units are derived from lysine monomers, but these lysine monomers do not form branched units (i.e., structural units that are simultaneously bonded to three other structural units by amide bonds), but rather form linear units (i.e., structural units that are bonded to two other structural units by amide bonds).

[0116] In this invention, the modified polylysine has a branched structure. The degree of branching of the modified polylysine can be 0.05-0.70, preferably 0.15-0.65.

[0117] In this invention, "branching degree (DB)" has the meaning commonly understood in the art, that is, it refers to the proportion of branched structural units to the total structural units, and is determined by the following formula:

[0118] Branching degree (DB) = (D+T) / (D+T+L)

[0119] Where D represents the number of branched structural units, T represents the number of end structural units, and L represents the number of linear structural units.

[0120] In this invention, the degree of branching of the modified polylysine can be 0.05, 0.06, 0.08, 0.10, 0.12, 0.14, 0.16, 0.18, 0.20, 0.22, 0.24, 0.26, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.42, 0.44, 0.46, 0.48, 0.50, 0.52, 0.54, 0.56, 0.58, 0.60, 0.62, 0.64, 0.66, 0.68, 0.70, or any range of two or more values, for example, 0.06-0.65.

[0121] In this invention, the following is adopted: 1 The proportions of lysine-based branched structural units, terminal structural units, and linear structural units were measured using H-NMR spectroscopy, and the degree of branching was calculated.

[0122] In this invention, the relative viscosity of the modified polylysine at 25°C is 1.2-5.0. In this invention, the relative viscosity of the modified polylysine at 25°C can be 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, or a range of any two or more values, for example, 1.3-5.0.

[0123] In this invention, the relative viscosity is the relative viscosity of modified polylysine at 25°C, measured using an Ubbelohde viscometer method with 96% concentrated sulfuric acid as the solvent.

[0124] In this invention, the weight-average molecular weight of the modified polylysine is 10,000 to 150,000. In this invention, the weight-average molecular weight of the modified polylysine can be 10,000, 20,000, 30,000, 40,000, 50,000, 60,000, 70,000, 80,000, 90,000, 100,000, 110,000, 120,000, 130,000, 140,000, 150,000, or any range of two or more values, for example, 20,000 to 150,000.

[0125] In this invention, the molecular weight distribution of the modified polylysine is 1.2-2.5. In this invention, the molecular weight distribution of the modified polylysine can be 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, or a range of any two or more values, for example, 1.3-2.5.

[0126] In this invention, the weight-average molecular weight and molecular weight distribution of the modified polylysine were determined by gel permeation chromatography (GPC).

[0127] In this invention, the hydrodynamic diameter of the modified polylysine is >50nm, preferably 50nm-1000nm, and more preferably 50nm-700nm. In this invention, the hydrodynamic diameter of the modified polylysine can be 55nm, 60nm, 70nm, 80nm, 90nm, 100nm, 120nm, 140nm, 160nm, 180nm, 200nm, 220nm, 240nm, 260nm, 280nm, 300nm, 320nm, 340nm, 360nm, 380nm, 400nm, 420nm, 440nm, 4... 60nm, 480nm, 500nm, 520nm, 540nm, 560nm, 580nm, 600nm, 620nm, 640nm, 660nm, 680nm, 700nm, 720nm, 740nm, 760nm, 780nm, 800nm, 850nm, 900nm, 950nm, 1000nm, or any range of two or more values, such as 60nm-700nm.

[0128] In this invention, the hydrodynamic diameter is determined in neutral phosphate buffer (neutral PBS buffer) at 25°C.

[0129] A second aspect of this disclosure provides a method for preparing modified polylysine, the method comprising:

[0130] Modified polylysine was prepared by polymerizing cyclic lysine monomers with nylon monomers in an inert atmosphere in the presence of a reaction aid.

[0131] The reaction aid is selected from amino acids;

[0132] The nylon monomer includes one or more of lactam compounds and nylon salts;

[0133] The cyclic lysine monomer has the structure shown in formula (1), the lactam compound has the structure shown in formula (2), and the nylon salt has the structure shown in formula (3).

[0134] [ + H3NR5NH3 +- OOCR4COO - Equation (3),

[0135] Among them, one of L1 and L2 is H and the other is R1; or, one of L1 and L2 is -R2-R' and the other is R1; or, L1 and L2 are both -R2-R'.

[0136] Among them, R1 is selected from H and C. 1-20 Substituted or unsubstituted alkyl, C 3-20 Substituted or unsubstituted cycloalkyl, C 6-20 Substituted or unsubstituted aromatic groups, and C 5-20 Substituted or unsubstituted heteroaryl groups;

[0137] Each R2 is independently selected from C. 1-20 Substituted or unsubstituted alkylene, C 3-20 Substituted or unsubstituted cycloalkylene, C 6-20 Substituted or unsubstituted aromatic groups, and C 5-20 Substituted or unsubstituted heteroaryl groups;

[0138] Each R' is independently selected from carboxyl, amino, amide, hydroxyl, isocyanate, and aldehyde groups;

[0139] Among them, R3, R4, and R5 are each independently selected from C. 1-20 Substituted or unsubstituted alkylene, C 3-20 Substituted or unsubstituted cycloalkylene, C 6-20 Substituted or unsubstituted aromatic groups, and C 5- 20 Substituted or unsubstituted heteroaryl groups; and

[0140] In this case, the substituents of R1, R2, R3, R4, and R5 are each independently selected from C. 1-10 alkyl, C 1-5 One or more of the alkoxy groups.

[0141] In this invention, according to some preferred embodiments of this disclosure, one of L1 and L2 is H and the other is R1; wherein, R1 is selected from H and C. 1-20 Substituted or unsubstituted alkyl, C 3-20 Substituted or unsubstituted cycloalkyl, C 6-20 Substituted or unsubstituted aromatic groups, and C 5-20 Substituted or unsubstituted heteroaryl group; preferably, R1 is selected from H, substituted or unsubstituted C. 1-5 Alkyl and C 6- 10 A substituted or unsubstituted aromatic group; more preferably, R1 is selected from H, methyl, ethyl, propyl, butyl, benzyl and phenyl.

[0142] In this invention, according to some embodiments of this disclosure, the substituents of R1, R2, R3, R4 and R5 are each independently selected from one or more of C1-6 alkyl groups and C1-4 alkoxy groups, such as one or more of methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy and butoxy.

[0143] This invention prepares a branched polyamide (modified polylysine) by mixing and reacting a lactam compound and / or nylon salt with a cyclic lysine derivative without adding an anionic initiator. The preparation method is simple and effectively reduces polymerization costs. Furthermore, the branched polyamide prepared using bioavailable amino acid derivatives as ring-opening agents and reactants exhibits good thermal stability, and the branching structure and active functional groups of the polyamide can be controlled to obtain different degrees of branching. In some embodiments, the modified polylysine of this invention exhibits good antibacterial properties and low cytotoxicity. The modified polylysine disclosed herein has a controllable melting point and solubility, is easy to further process, and broadens the application fields of polyamides, enabling its use in antibacterial, UV protection, optical anti-counterfeiting, and antistatic materials.

[0144] In this disclosure, the carbon number includes the carbon number of the substituent. For example, C 1-20 The carbon number of a substituted or unsubstituted alkyl group includes the carbon number of the alkyl group and the carbon number of the substituents on the alkyl group.

[0145] In some embodiments of this invention, R1 is selected from H and C. 1-15 Substituted or unsubstituted alkyl, C 3-15 Substituted or unsubstituted cycloalkyl, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R1 selected from H, C 1-6 Substituted or unsubstituted alkyl, C 3-8 Substituted or unsubstituted cycloalkyl, C 6-10 Substituted or unsubstituted aromatic groups, C 5-10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R1 is selected from C 1-5 alkyl, C 1-5The alkoxy group is selected from one or more of H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted phenyl, substituted or unsubstituted furanyl, and wherein the substituent of R1 is selected from one or more of methyl, ethyl, propyl, butyl, ethoxy, and propoxy. The above embodiments are advantageous for preparing branched modified polylysine without using anionic polymerization initiators, which helps reduce polymerization costs and facilitates further processing and broadens the application range of the modified polylysine.

[0146] In some embodiments of this invention, R2 is selected from C. 1-15 Substituted or unsubstituted alkylene, C 3-15 Substituted or unsubstituted cycloalkylene, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R2 selected from C 1-6 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups, C 5-10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R2 is selected from C 1-5 alkyl, C 1-5 The alkoxy group of R2 is selected from one or more of the following: methyl, ethyl, propyl, propyl, butyl, pentyl, cyclopentyl, cyclohexyl, phenyl, and furanyl groups. The above embodiments facilitate the preparation of branched modified polylysine without the use of anionic polymerization initiators, reduce polymerization costs, and allow for further processing and wider application of the modified polylysine.

[0147] In some embodiments of this invention, R3 is selected from C. 2-12 Substituted or unsubstituted alkylene, C 3-15 Substituted or unsubstituted cycloalkylene, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R3 selected from C 2-11 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C6-10 Substituted or unsubstituted aromatic groups, C 5-10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R3 is selected from C 1-5 alkyl and C 1-5 One or more of the alkoxy groups; preferably, R3 is selected from one or more of ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, and undecylene, and wherein the substituents of R3 are selected from one or more of methyl, ethyl, propyl, and butyl.

[0148] In some embodiments of this invention, R4 and R5 are each independently selected from C. 1-18 Substituted or unsubstituted alkylene, C 3-18 Substituted or unsubstituted cycloalkylene, C 6-18 Substituted or unsubstituted aromatic groups and C 5-20 One or more of substituted or unsubstituted heteroaryl groups, preferably R4 and R5 each independently selected from C 1-12 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups and C 5-10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituents R4 and R5 are each independently selected from C 1-5 alkyl, C 1-5 One or more of the alkoxy groups; preferably, R4 and R5 are each independently selected from one or more of ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, substituted or unsubstituted furanylene, and wherein the substituents of R4 and R5 are each independently selected from one or more of methyl, ethyl, propyl and butyl.

[0149] In this invention, according to some embodiments of this disclosure, the lactam compound can be C 4-15 The lactam is preferably selected from one or more of butyrolactam, valproic acid lactam, caprolactam, heptalactam, octyllactam, nonanolactam, decanolactam, undecyllactam, dodecalactam, and tridecalactam; more preferably, it is caprolactam.

[0150] In this invention, according to some embodiments of this disclosure, the nylon salt is selected from nylon 46 salt, nylon 4T salt, nylon 56 salt, nylon 5T salt, nylon 66 salt, nylon 6T salt, nylon 6I salt, nylon 610 salt, nylon 612 salt, nylon MXD6 salt, nylon 9T salt, nylon 910 salt, nylon 912 salt, nylon 1010 salt, nylon 10T salt, nylon 1012 salt, nylon 1212 salt, and nylon 12T salt. The nylon salt is selected from one or more of nylon PACM6 salt, nylon PACMT salt, nylon PACMI salt, nylon MACMT salt, and nylon MACMI salt; preferably, the nylon salt is selected from one or more of nylon 66 salt, nylon 56 salt, nylon 6T salt, nylon MXD6 salt, nylon 9T salt, and nylon 10T salt; more preferably, the nylon salt is selected from one or more of nylon 66 salt, nylon 6T salt, and nylon MXD6 salt.

[0151] In this invention, according to some embodiments of this disclosure, the cyclic lysine monomer is selected from compounds of formula (1) in which one of L1 and L2 is H and the other is R1; preferably, R1 is selected from H, substituted or unsubstituted C. 1-5 Alkyl and C 6-10 A substituted or unsubstituted aromatic group; more preferably, R1 is selected from H, methyl, ethyl, propyl, butyl, benzyl and phenyl.

[0152] In this invention, according to some embodiments of this disclosure, the cyclic lysine monomer is selected from one or more of α-amino-ε-caprolactam, α-(N-methyl)amino-ε-caprolactam, α-(N-ethyl)amino-ε-caprolactam, α-(N-propyl)amino-ε-caprolactam, α-(N-butyl)amino-ε-caprolactam, and α-(N-benzyl)amino-ε-caprolactam. The above embodiments are beneficial for obtaining modified polylysine with high branching degree and good solubility, further improving the antibacterial properties of the modified polylysine.

[0153] In some preferred embodiments of the present invention, the cyclic lysine monomer is selected from compounds of formula (1) in which one of L1 and L2 is H and the other is R1, wherein preferably, R1 is selected from H, substituted or unsubstituted C. 1-5 Alkyl and C 6-10 A substituted or unsubstituted aromatic group; more preferably, R1 is selected from H, methyl, ethyl, propyl, butyl, benzyl, and phenyl; preferably, the cyclic lysine monomer is selected from one or more of α-amino-ε-caprolactam, α-(N-methyl)amino-ε-caprolactam, α-(N-ethyl)amino-ε-caprolactam, α-(N-propyl)amino-ε-caprolactam, α-(N-butyl)amino-ε-caprolactam, and α-(N-benzyl)amino-ε-caprolactam; and the lactam compound is C4-10 The lactam is preferably selected from one or more of butyrolactam, valproic acid lactam, caprolactam, heptalactam, octyllactam, nonanolactam, and decanolactam; more preferably, it is caprolactam.

[0154] In some embodiments of the present invention, the content of the cyclic lysine monomer in the total monomer content is 1wt%-95wt%, preferably 10wt%-95wt%, and more preferably 15wt%-90wt%. In some embodiments, the content of the cyclic lysine monomer in the total monomer content can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 23wt%, 25wt%, 27wt%, 30wt%, 33wt%, 35wt%, 37wt%, 40wt%, 43wt%, or 45wt%. 47wt%, 50wt%, 53wt%, 55wt%, 57wt%, 60wt%, 63wt%, 65wt%, 67wt%, 70wt%, 73wt%, 75wt%, 77wt%, 80wt%, 81wt%, 82wt%, 83wt%, 84wt%, 85wt%, 86wt%, 87wt%, 88wt%, 89wt%, 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, or any range of two of the above values, such as 16wt%-89wt%.

[0155] In some embodiments of the present invention, the mass ratio of the cyclic lysine monomer to the nylon monomer can be 1:99-95:5, preferably 10:90-95:5, more preferably 15:85-90:10, for example 10:90-80:20. In this invention, the mass ratio of the cyclic lysine monomer to the nylon monomer can be 1:95, 2:95, 3:95, 4:95, 5:95, 7:93, 10:90, 13:87, 15:85, 20:80, 23:77, 25:75, 30:70, 33:67, 35:65, 40:60, 43:57, 45:55, 50:50, 53:47, 55:45, 60:40, 63:37, 65:35, 70:30, 73:27, 75:25, 80:20, 83:17, 85:15, 90:10, 95:5, or any range of two or more values, such as 10:90-90:10. The above-described embodiments are beneficial for obtaining modified polylysine with high branching degree and good solubility, further improving the antibacterial properties of modified polylysine, while also giving it low cytotoxicity.

[0156] In this invention, the reaction aid may include one or more of aminobutyric acid, aminovaleric acid, aminohexanoic acid, aminoheptanoic acid, aminooctanoic acid, and arginine, more preferably aminohexanoic acid. In this invention, the reaction aid may account for 0.5-10% of the total mass of the reactants, preferably 2-5%. In this invention, the total mass of the reactants refers to the sum of the masses of the cyclic lysine monomer, the nylon monomer, and the reaction aid. The above embodiments are advantageous for preparing branched modified polylysine without using anionic polymerization initiators, are advantageous for reducing polymerization costs, and are advantageous for obtaining modified polylysine with a lower proportion of branched lysine repeating units, a higher proportion of "ε-polymerization," a higher molecular weight, a lower monomer residue, and a higher degree of random copolymerization at lower polymerization temperatures.

[0157] In the method of this invention, anionic polymerization catalysts commonly used in the art for the polymerization of cyclic lysine derivatives are not used. In the method of this invention, water or acids commonly used for the polymerization of amino acids, lactams, etc., are not used. Therefore, in the method of this invention, anionic polymerization catalysts, water, and acids commonly used in the art are not added. The acids are, for example, mono- or poly-fatty acids or aromatic acids, such as terephthalic acid, isophthalic acid, adipic acid, oxalic acid, benzoic acid, acetic acid, etc. However, as those skilled in the art will understand, the raw materials used in the method of this invention, such as cyclic lysine monomers and / or nylon monomers, may contain some water. Water entrained in the raw materials may be present in the method of this invention, but water is not added separately in the method of this invention. In this invention, "adding water separately" includes adding water directly during the implementation of the method, adding water in the form of an aqueous solution of the raw materials, adding water in the form of a hydrate of the raw materials, such as a lysine hydrate, etc.

[0158] In this invention, a conventional inert atmosphere commonly used in the preparation of polyamides can be used. According to some embodiments of this disclosure, the inert atmosphere may include one or more of nitrogen, helium, and argon.

[0159] In this invention, the conditions for the polymerization reaction may include: a polymerization temperature of 70-280°C, preferably 100-270°C, more preferably 140-260°C, and even more preferably 140-250°C; a time of 0.5-24h, preferably 4-14h; and a pressure of 0-1.5MPa, preferably 0.2-0.6MPa.

[0160] In this invention, the polymerization temperature can be 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, or any range of two or more values, such as 140-270℃.

[0161] In some embodiments of the present invention, the polymerization temperature can be 150-200°C, for example, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, or a range of any two or more values, such as 160-195°C.

[0162] In this invention, the polymerization time can be 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h, or any range of two or more values, such as 3-12h.

[0163] In this invention, the polymerization pressure can be 0 MPa, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, or any range of two or more values, such as 0.1-0.6 MPa.

[0164] In this invention, the polymerization can be carried out under stirring conditions. Those skilled in the art can suitably select the stirring rate, for example, the stirring rate can be 20-400 r / min, preferably 50-150 r / min.

[0165] The above-described embodiments facilitate the preparation of branched modified polylysine without the use of anionic polymerization initiators, reduce polymerization costs and impurity content in the polymerization products, and enable further processing of modified polylysine and broaden its application range.

[0166] In some embodiments of this invention, the polymerization reaction may include a first polymerization stage and a second polymerization stage, wherein the second polymerization stage is performed after the first polymerization stage. In this invention, the conditions for the first polymerization stage may include: a temperature of 100-210°C, preferably 140-200°C, and a time of 1-8 hours, preferably 2-4 hours; and the conditions for the second polymerization stage may include: a temperature of 200-280°C, preferably 200-260°C, and a time of 1-9 hours, preferably 1-4 hours. Optionally, the first and second polymerization stages may be carried out under stirring conditions, for example, a stirring rate of 50-150 r / min, preferably 80-120 r / min. The above embodiments are advantageous in avoiding the thermal decomposition or isomerization of cyclic lysine monomers, in increasing the molecular weight of the product, and in preparing products with low insoluble matter or low residual monomer content. In some embodiments, the temperature of the first polymerization stage can be 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, or a range of any two or more values, such as 140-210°C. In some embodiments, the duration of the first polymerization stage can be 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, or a range of any two or more values, such as 2-5 hours. In some embodiments, the temperature of the second polymerization stage can be 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, or a range of any two or more values, such as 200-270°C. In some implementations, the duration of the second aggregation phase can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, or a range of any two or more values, such as 1-5h.

[0167] In this invention, the first polymerization stage is not limited to a single temperature, but may include one or more polymerization temperatures (preferably 1, 2, or 3 polymerization temperatures, and preferably with progressively increasing temperatures) and may remain at each polymerization temperature for a certain period of time (preferably 0.5h-3h, for example, 0.5h, 1h, 2h, or 3h), provided that the one or more temperatures are within the temperature range of the first polymerization stage described above and the total polymerization time is within the polymerization time range of the first polymerization stage described above. In this invention, if multiple polymerization temperatures are used in the first polymerization stage, the temperature difference between these polymerization temperatures can each be independently between 5°C and 80°C, for example, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 70°C, 80°C, or any range consisting of two or more values, for example, 10°C-50°C. For example, the first polymerization stage may include two temperatures, 150°C and 180°C, with polymerization occurring at each temperature for 1h or 2h.

[0168] In this invention, the second polymerization stage is not limited to a single temperature, but may include one or more polymerization temperatures (preferably 1, 2, or 3 polymerization temperatures, and preferably with progressively increasing temperatures) and may remain at each polymerization temperature for a certain period of time (preferably 0.5h-3h, for example, 0.5h, 1h, 2h, or 3h), provided that the one or more temperatures are within the temperature range of the second polymerization stage described above and the total polymerization time is within the polymerization time range of the second polymerization stage described above. In this invention, if multiple polymerization temperatures are used in the second polymerization stage, the temperature difference between these polymerization temperatures may each be independently between 5°C and 70°C, for example, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 70°C, or a range consisting of any two or more values, for example, 10°C-50°C. For example, the second polymerization stage may include two temperatures, 210°C and 230°C, with each polymerization reaction lasting 1h or 2h at each temperature.

[0169] In this invention, the number of temperatures used in the first polymerization stage is independent of the number of temperatures used in the second polymerization stage. For example, the first polymerization stage can independently use 1, 2, or 3 polymerization temperatures, and the second polymerization stage can independently use 1, 2, or 3 polymerization temperatures.

[0170] In some embodiments of the present invention, the method may further include: after the polymerization reaction has proceeded, depressurizing the reaction system and allowing the reaction system to continue reacting under a second pressure; wherein the second pressure is 0.0 to -0.1 MPa, preferably 0.0 to -0.09 MPa, and the reaction time under the second pressure is 0.5 to 16 h, preferably 0.5 to 10 h. The above embodiments are beneficial for increasing the molecular weight or relative viscosity of the product. In some embodiments, the second pressure may be 0.0 MPa, -0.01 MPa, -0.02 MPa, -0.03 MPa, -0.04 MPa, -0.05 MPa, -0.06 MPa, -0.07 MPa, -0.08 MPa, -0.09 MPa, or a range consisting of any two or more values, for example, -0.1 MPa to -0.09 MPa. In some implementations, the reaction time under the second pressure can be 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, or a range of any two or more values, such as 0.5-11h.

[0171] In some preferred embodiments, the modified polylysine prepared by the method of the second aspect of this disclosure is the modified polylysine described in the first aspect of this invention.

[0172] This disclosure provides a third aspect of a composition comprising the modified polylysine described in the first aspect of the invention. The invention does not particularly limit the form of the composition; for example, the composition may be in the form of a dispersion, powder, wire, fiber, film, coating, sheet, plate, irregular material, porous material, or gel material. Those skilled in the art can select a suitable composition form according to the specific application field and usage requirements.

[0173] This fourth aspect of the disclosure provides the use of the modified polylysine described in the first aspect of the disclosure as an antibacterial agent.

[0174] According to some embodiments of this disclosure, the modified polylysine has an antibacterial rate of 90% or more against Escherichia coli, preferably 99% or more; more preferably, the modified polylysine has an antibacterial rate of 99.9% or more against Escherichia coli.

[0175] In some embodiments of the present invention, the modified polylysine has an antibacterial rate of 90% or more against Staphylococcus aureus, preferably 99% or more; more preferably, the modified polylysine has an antibacterial rate of 99.9% or more against Staphylococcus aureus.

[0176] In some embodiments of the present invention, the survival rate of NIH 3T3 cells is higher than 50% in a neutral phosphate buffer (neutral PBS buffer) of the modified polylysine at a concentration of 1.5 mg / ml.

[0177] In some embodiments of the present invention, the modified polylysine is used as an antibacterial agent in solid form. In some embodiments of the present invention, the modified polylysine is used as an antibacterial agent after being dissolved in a solvent; preferably, the solvent is selected from one or more of water, alcohols, esters, ethers, furans, ketones, and hydrocarbon organic solvents, and more preferably from one or more of water, ethanol, ethyl acetate, tetrahydrofuran, acetone, and cyclohexane.

[0178] This fifth aspect of the disclosure provides the application of the modified polylysine described in the first aspect of the disclosure in optical materials. In some embodiments, the modified polylysine has a transmittance of less than 60% at a 300 nm UV wavelength. In some embodiments, the modified polylysine has a fluorescence excitation wavelength between 200 and 650 nm and an emission wavelength between 400 and 800 nm.

[0179] The sixth aspect of this disclosure provides the application of the modified polylysine described in the first aspect of this disclosure in antistatic agents, adhesives, sealants, water treatment agents, drug carriers, cement water-reducing agents, inks, fabric finishing agents, and fiber colorants.

[0180] According to some embodiments of this disclosure, the surface resistivity of the modified polylysine of the present invention is less than 10 × 10⁻⁶. 11 Ω, therefore it can be used as an electrostatic dissipative material.

[0181] Example

[0182] The present disclosure will be described in detail below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present disclosure, but do not limit the present disclosure in any way.

[0183] The α-amino-ε-caprolactam (ACL, CAS No.: 671-42-1), caprolactam (CPL, CAS No.: 105-60-2), aminocaproic acid (AS, CAS No.: 60-32-2), arginine (CAS No.: 74-79-3), and lysine (CAS No.: 56-87-1) used in this disclosure are all commercially available products with a purity >95%. α-(N-methyl)amino-ε-caprolactam (MACL) and α-(N-benzyl)amino-ε-caprolactam (PACL) are prepared by the methods described in CN119684209A and CN103694174B.

[0184] Degree of branching: The polymer was dissolved in deuterated-trifluoroacetic acid and measured using a Bruker Avance NEO 500M NMR instrument. 1 The proportions of branched structural units, linear structural units, and terminal structural units are obtained from the H NMR spectrum based on the peak position and peak integral area, and the degree of branching is calculated.

[0185] Infrared spectral characterization: Fourier transform infrared (FT-IR) spectra were measured using a Bruker INVENIO FT-IR instrument in ATR mode with a resolution of 4 cm⁻¹. -1 Test range 400-4000cm -1 The sample was scanned 32 times.

[0186] Insoluble matter analysis: The polymer granules were dispersed in trifluoroethanol at a concentration of 2 wt%. After shaking at room temperature for 24 h, the dispersion was filtered or centrifuged. The dry weight of the insoluble matter was the mass of the insoluble matter in the polymer.

[0187] Residual monomer analysis: The polymer granules were dispersed in ethanol at a concentration of 2 wt%, and after shaking at room temperature for 24 h, the dispersion was filtered or centrifuged. The dry weight of the soluble matter was the mass of the residual monomer in the polymer.

[0188] Melting point and glass transition temperature: Measurements were performed using a Mettler DSC3 differential scanning calorimeter under a nitrogen atmosphere at a temperature control rate of 10℃ / min. The test temperature range was -20℃ to 260℃. The melting point and glass transition temperature were analyzed based on the second melting curve.

[0189] Thermal stability performance: Characterized using a Mettler RT-800 thermogravimetric analyzer, with a heating rate of 10℃ / min, a test temperature range of 40-600℃, and measurements taken under a nitrogen atmosphere.

[0190] Relative viscosity: The relative viscosity of the polymer at 25°C was measured using an Ubbelohde viscometer with 96% concentrated sulfuric acid as the solvent.

[0191] Molecular weight and its distribution: The sample was dissolved in hexafluoroisopropanol at a concentration of 0.1 mg / mL, filtered through a 0.45 μm filter membrane, and the molecular weight and its distribution were tested using an Agilent PL-GPC220 micrometer.

[0192] Photoluminescence properties: The sample was hot-pressed into a thin film at a temperature 30°C above the melting point, and the fluorescence intensity was analyzed on a fluorescence lifetime and steady-state spectrometer (FLS 980, Edinburgh Instruments).

[0193] The light transmittance of the polymer film was tested using a PerkinElmer Lambda 950 UV-Vis spectrophotometer equipped with an integrating sphere.

[0194] Surface resistance: Measured using a Hima AS982 surface resistance tester at a test temperature of 25℃.

[0195] Antibacterial rate: Tested according to the shaking flask test 2.1.8.7 of the "Disinfection Technical Specifications (2002 Edition)" issued by the Ministry of Health of the People's Republic of China. Before testing, residual reactive substances in the sample were removed according to the test method for fiber-grade polycaprolactam (PA6).

[0196] Cytotoxicity assay: The test sample was dissolved in complete culture medium to prepare a 10 mg / mL stock solution, which was further diluted to working solutions of 0.002, 0.01, 0.05, 0.2, 0.5, 1, and 1.5 mg / mL. The solutions were then sterilized by filtration through a 0.22 μm filter membrane. 100 μL of the working solution was added to each well, and 100 μL of complete culture medium was added to each well for the control group; each treatment group was performed in triplicate. NIH 3T3 cells in logarithmic growth phase were collected, cell counts were performed, and cell concentration was adjusted to 8 × 10⁻⁶ cells / well. 3 Cells were seeded into 96-well plates and cultured overnight in a 5% CO2, 37°C incubator to allow cell adhesion. Following the same grouping and treatment, cells were cultured for 24 hours. The culture medium was removed, and each well was washed three times with PBS. 100 μL of medium containing 0.5 mg / mL MTT was added to each well, and the cells were cultured in a 5% CO2, 37°C incubator for 4 hours. The supernatant was discarded, and 100 μL of DMSO was added to each well. The cells were gently shaken for 10 minutes, and the absorbance at 490 nm was measured. The relative cell viability was calculated (relative viability % = (experimental group OD value / mean OD value of control group) × 100).

[0197] Hydrodynamic diameter test: The sample was dispersed in neutral PBS buffer at a concentration of 0.1-1 mg / mL, and the particle diameter was measured using a Malvern Zetasizer Nano ZS90.

[0198] Examples 1-10 and Comparative Examples 1-3

[0199] Add 90g caprolactam (CPL), 10g aminocaprolactam (ACL), and 5g aminocaproic acid (AS) to a pressure-resistant reaction vessel, heat to 80℃, set the stirring speed to 100r / min, then replace the air in the vessel with nitrogen, and maintain the pressure to 0.3MPa; raise the temperature to 180℃ and react under these conditions for 10h; stop stirring, slowly release the pressure, and open the vessel to remove the reaction product after the pressure drops to 0MPa.

[0200] The methods used in Examples 2-10 and Comparative Examples 1-3 are the same as in Example 1, except that the reactants used are different, as detailed in Table 1. In the above examples and comparative examples, the reaction system was pressurized, with a maximum pressure of <0.6 MPa.

[0201] Table 1

[0202] Examples 11-19

[0203] CPL, ACL, and AS were added to a pressure-resistant reaction vessel and heated to 80°C. The stirring speed was set to 100 r / min, and the air in the vessel was replaced with nitrogen. The pressure was maintained at 0.3 MPa. The temperature was increased to 150°C and 180°C, and the reaction was carried out at each temperature for 1.5 h. Then the temperature was increased to 210°C and 230°C, and the reaction was carried out at each temperature for 2 h and 1 h, respectively. The pressure was slowly released to 0 MPa, and the reaction was continued at 230°C for 1 h. The stirring was stopped, the vessel was opened, and the reaction product was removed.

[0204] In Examples 11-19, the mass ratios of CPL, ACL, and AS were 90:10:3; 80:20:3; 70:30:3; 60:40:3; 50:50:3; 40:60:3; 30:70:3; 20:80:3; and 10:90:3, respectively. In the above examples, the reaction system was self-pressurized, with the maximum pressure ranging from 0.6 to 1.1 MPa.

[0205] Examples 20 and 21

[0206] The methods in Examples 20 and 21 are the same as in Example 11, but the reactants are different. In Example 20, the masses of reactants CPL, ACL, and AS are 40.74 g, 30.76 g, and 2.36 g, respectively; in Example 21, the masses of reactants CPL, ACL, and arginine are 40.74 g, 30.76 g, and 3.14 g, respectively.

[0207] Examples 22, 23 and Comparative Example 4

[0208] The methods used in Examples 22, 23, and Comparative Example 4 were the same as in Example 11, but the reactants were different. In Examples 22 and 4, the masses of monomers CPL and ACL were 79.21 g and 0.90 g, respectively; in Example 23, the masses of monomers CPL and ACL were 79.21 g and 4.49 g, respectively; 2.75 g of AS was added in Examples 22 and 23, while 3.78 g of deionized water was added in Comparative Example 4 without adding AS.

[0209] Comparative Example 5

[0210] The reactants for Comparative Example 5 were the same as those for Comparative Example 4, but the reaction temperature was different. CPL, ACL, and deionized water were added to a pressure-resistant reaction vessel, heated to 80°C, and then the air inside the vessel was replaced with nitrogen, maintaining the pressure at 0.3 MPa. The temperature was then increased to 230°C, the stirring speed was set to 100 r / min, and the reaction was carried out under these conditions for 3 h. The temperature was then increased to 260°C, the stirring speed was set to 100 r / min, and the reaction was carried out under these conditions for 2 h. The pressure was then slowly released to 0 MPa, and the reaction was continued for 1 h. The stirring was stopped, the vessel was opened, and the reaction product was removed.

[0211] Comparative Examples 6 and 7

[0212] The methods used in Comparative Examples 6 and 7 were the same as those in Comparative Example 5, but the reactants were different. In Comparative Example 6, the masses of reactants CPL, ACL, and deionized water were 43.55 g, 18 g, and 1.8 g, respectively; in Comparative Example 7, the mass ratios of reactants CPL, lysine, and deionized water were 43.55 g, 20.53 g, and 1.8 g, respectively.

[0213] Examples 24-28

[0214] The reactants in Examples 24-28 are the same as those in Example 11, and the specific methods are as follows: The reactants are added to a pressure-resistant reaction vessel, heated to 80°C, and the stirring speed is set to 100 r / min. The air in the vessel is then replaced with nitrogen, and the pressure is maintained at 0.3 MPa. The temperature is raised to 150°C and 180°C, and the reaction is carried out at each temperature for 1.5 h. Then the temperature is raised to 210°C and 230°C, and the reaction is carried out at each temperature for 2 h and 1 h, respectively. The pressure is slowly released to 0 MPa. After depressurization polymerization is carried out under the conditions shown in Table 2, stirring is stopped, nitrogen is introduced to restore the pressure to normal, and the reaction product is taken out of the vessel.

[0215] Table 2

[0216] Examples 29-32 and Comparative Example 8

[0217] CPL, ACL, and AS were added to a pressure-resistant reaction vessel and heated to 80°C. The air inside the vessel was then replaced with nitrogen, and the pressure was maintained at 0.3 MPa. The temperature was then raised to 180°C, the stirring speed was set to 100 r / min, and the reaction was carried out for 3 hours under these conditions. The temperature was then raised to 230°C, the stirring speed was set to 100 r / min, and the reaction was carried out for another 3 hours under these conditions. The stirring was stopped, the pressure was slowly released, and the vessel was opened and the reaction product was removed after the pressure dropped to 0 MPa. In Examples 29-32 and Comparative Example 8, the mass ratios of CPL, ACL, and AS were 90:10:3; 95:5:3; 98:2:3; 99:1:3; and 99.5:0.5:3, respectively.

[0218] Test Example 1

[0219] The products obtained in Examples 1-5 and Comparative Examples 1-3 were characterized by infrared spectroscopy, as shown in Figure 1; wherein, 3300 cm⁻¹ -1 The absorption peak for the stretching vibration of -NH- is at 2860 cm⁻¹. -1 The absorption peak at 2930 cm⁻¹ is the symmetric stretching vibration of -CH₂-. -1 The absorption peak at 1640 cm⁻¹ is the antisymmetric stretching vibration of -CH₂-. -1 The absorption peak at 1550 cm⁻¹ is the -C=O stretching vibration peak. -1 The presence of the -NH- bending vibration absorption peak at 3300 cm⁻¹ indicates the formation of polyamide. With increasing ACL content in the monomer, the resulting polyamide showed an absorption peak at 3300 cm⁻¹. -1 1640cm -1 and 1550cm -1 The absorption peak at that point is no longer sharp, indicating that copolymerization and the introduction of branched structures weaken the hydrogen bonds and reduce the regularity of the polymer.

[0220] Test Example 2

[0221] The products obtained in Examples 1-5 were characterized by 1H NMR spectroscopy, as shown in Figure 2. The characteristic peaks and their integrated areas were assigned as follows.

[0222] Table 3

[0223] Ratio A refers to the proportion of lysine-branched repeating units based on the total amount of lysine repeating units, where ratio A = M4 / [(M1 / 6-M2 / 2)×E]×%, and E is the molar proportion of lysine repeating units in modified polylysine (calculated from the feed ratio).

[0224] Ratio B refers to the proportion of lysine-branched repeating units based on the total number of repeating units, where ratio B = M4 / (M1 / 6-M2 / 2)×%.

[0225] The proportion C refers to the proportion of lysine-branched repeating units in "ε-polymerization" based on the total amount of lysine-branched repeating units, where the proportion C = M5 / M4 × .

[0226] The degree of branching of modified polylysine is calculated as (M4 + M3 / 2 - M6 / M4 × E × (M1 / 6 - M2 / 2) × (1 - A)) / (M1 / 6 - M2 / 2), where the proportion of "α-polymerization" in linear lysine repeating units is considered to be the same as the proportion of "α-polymerization" in branched lysine repeating units.

[0227] As shown in Figure 2, the proportions of the products obtained in Examples 1-5 are as follows: A: 0.1%, 59.38%, 61.73%, 73.22%, and 88.18%; B: 0.01%, 10.28%, 16.22%, 32.83%, and 56.70%; and C: 60.71%, 40.72%, 54.82%, 62.61%, and 53.99%.

[0228] The degrees of branching of the modified polylysine obtained in Examples 1-5 were 0.085, 0.165, 0.221, 0.318, and 0.373, respectively. Among them, the product of Example 1 eluted at 4.2-4.6 ppm, but its integral area was too small (Figure 2), so the values ​​of ratio A and ratio B are mainly used as orders of magnitude reference.

[0229] Test Example 3

[0230] The products obtained in Examples 6-32 and Comparative Examples 1-8 were characterized by proton NMR spectroscopy. The proportions A, B, and C and the degree of branching were calculated using the same method as in Test Example 2. The results are shown in Table 4.

[0231] As shown in Table 4, at similar lysine monomer contents, the products of the embodiments of the present invention exhibit a higher proportion of linear structures and / or "ε-polymer" structures. When the ACL proportion in the monomer mixture is <1 wt%, as shown in Comparative Examples 1, 2, and 8, the obtained products do not show a peak at 4.2-4.6 ppm, indicating that they do not possess lysine branched repeating units. As shown in the proportion A data of Comparative Examples 4 and 5, they do not meet the requirement that when the content of lysine repeating units is <5 wt%, the proportion of repeating units producing branched structures in the lysine repeating units is <10%; as shown in the proportion C data of Comparative Examples 4-7, the mass proportion of ε-polymers in their lysine branched repeating units does not exceed 30%.

[0232] Table 4

[0233] Test Example 4

[0234] The melting point and glass transition temperature of the products obtained in Examples 1-5, Example 13, Example 22, Examples 29-32, and Comparative Examples 5-7 were tested.

[0235] The melting points of the products obtained in Examples 1-3 are 196.6℃, 172.0℃, and 147.5℃, respectively; Examples 4 and 5 have no obvious melting points, and their glass transition temperatures are 41.1℃ and 40.8℃, respectively; the melting points of the products obtained in Examples 29-32 are 197.3℃, 203.5℃, 212.1℃, and 216.6℃, respectively. Therefore, this disclosure can obtain semi-crystalline modified polylysine or amorphous modified polylysine with melting points between 140-220℃.

[0236] With similar monomer compositions, the product obtained in Example 13 had no obvious melting point, and its glass transition temperature was 25.8°C. The products obtained in Comparative Examples 6 and 7 both exhibited cold crystallization, with crystallization temperatures of 101.4°C and 104.8°C, respectively; melting points of 149.6°C and 145.4°C, respectively; and glass transition temperatures of 22.0°C and 20.2°C, respectively. The melting points of the products obtained in Example 22 and Comparative Example 5 were 216.8°C and 218.8°C, respectively. The comparison shows that the modified polylysine of this invention has higher structural randomness, a lower melting point, and is easier to process.

[0237] Test Example 5

[0238] The granules obtained from Examples 1-3, Examples 11-13 and Comparative Examples 4-7 were dispersed in trifluoroethanol, shaken for 24 hours, and the dispersions were separated. The content of insoluble matter in the products was then calculated.

[0239] The product granules obtained from Examples 1-3, Examples 11-13 and Comparative Examples 4-7 were dispersed in ethanol, shaken for 24 hours, the dispersions were separated, and the residual monomer content in the products was calculated.

[0240] No insoluble matter was observed in the products obtained in Examples 1-3, Examples 11-13 and Comparative Example 4; the insoluble matter content of the products obtained in Comparative Examples 5-7 was 0.6 wt%, 3.2 wt%, and 4.1 wt%, respectively.

[0241] The residual monomer contents in the products obtained in Examples 1-3, Examples 11-13 and Comparative Examples 4-7 were 8.3 wt%, 9.2 wt%, 10.0 wt%, 8.6 wt%, 8.9 wt%, 9.7 wt%, 29.8 wt%, 11.4 wt%, 17.5 wt%, and 16.7 wt%, respectively.

[0242] Figure 3 shows the ethanol dispersions of the products obtained in Example 13, Comparative Example 6 and Comparative Example 7 under natural light (from left to right). It can be seen that the dispersions of the comparative example products are relatively turbid and contain a high proportion of by-products.

[0243] Test Example 6

[0244] The RGB values ​​of the products obtained in Example 13, Comparative Example 6, and Comparative Example 7 were measured using a Japanese SE6000 spectrophotometer in the wavelength range of 380-780 nm. The RGB values ​​of the products obtained in Example 13, Comparative Example 6, and Comparative Example 7 were (215, 215, 157), (208, 170, 43), and (190, 140, 29), respectively. It can be seen that the products of the embodiments of the present invention have lower color deviation, lighter chroma, and higher brightness.

[0245] Test Example 7

[0246] The products obtained in Examples 4, 5, and 14-19 were subjected to solubility tests by dispersing 0.2 g of the sample in 10 mL of solvent and stirring for 1 h. The results showed that the modified polylysine obtained in the above examples was soluble in water and ethanol, and showed no significant gel formation.

[0247] Test Example 8

[0248] The relative viscosities of the products obtained in Examples 1, 11, 24-28, and 29-32 were tested. The relative viscosities of the products obtained in Examples 1 and 29 were 3.5 and 4.2, respectively; indicating that the two-stage polymerization of this disclosure can improve the relative viscosity of modified polylysine. The relative viscosities of the products obtained in Examples 11, 24-28 were 4.1, 4.3, 4.5, 4.7, 4.2, and 4.4, respectively; indicating that reduced pressure polymerization can further improve the relative viscosity. The relative viscosities of the products obtained in Examples 29-32 were 3.7, 3.2, 2.8, and 2.5, respectively; indicating that when the proportion of lysine repeating units is ≤10wt%, increasing the ACL content can increase the relative viscosity of the product.

[0249] Test Example 9

[0250] The products obtained in Examples 1 and 29-32 were subjected to molecular weight testing. As shown in Figure 4, the weight-average molecular weight of the product obtained in Example 29 was 111,000, and the molecular weight distribution (polydispersity index) was 1.53. The weight-average molecular weights of the products obtained in Examples 1, 30-32 were 43,000, 103,000, 88,000, and 76,000, respectively, and the molecular weight distribution (polydispersity index) were 1.49, 1.71, 1.64, and 1.84, respectively.

[0251] Test Case 10

[0252] The products obtained in Examples 16-19 were subjected to hydrodynamic diameter testing, and their hydrodynamic diameters in phosphate buffer were 82.3 nm, 158.5 nm, 304.6 nm, and 363.8 nm, respectively. The test results of Example 17 are shown in Figure 5.

[0253] Test Example 11

[0254] The products obtained in Examples 1 and 29 were subjected to thermal stability tests, and the results are shown in Figure 6. The 5% thermal weight loss temperature of the product obtained in Example 29 was 323.3°C, while that of the product obtained in Example 1 was 178.0°C. The comparison shows that the two-stage polymerization of this disclosure can improve the thermal stability of the obtained modified polylysine.

[0255] Test Example 12

[0256] The products obtained in Examples 1-5 and Examples 11-19 were subjected to thermal stability tests. The residual weights of the products obtained in Examples 1-5 at 400°C were 76.97%, 64.72%, 61.44%, 51.30%, and 46.62%, respectively; the residual weights of the products obtained in Examples 11-19 at 400°C were 83.43%, 69.51%, 65.75%, 60.89%, 56.69%, 52.04%, 47.93%, 45.04%, and 44.71%, respectively. This indicates that the thermal stability of the modified polylysine increases with the increase of the nylon monomer ratio.

[0257] Test Example 13

[0258] The products obtained from Comparative Examples 4 and 5 were subjected to thermal stability tests. The residual weights of the products obtained from Comparative Examples 4 and 5 at 240℃ were 78.15% and 95.40%, respectively, and the residual weights at 400℃ were 63.40% and 84.50%, respectively. It can be seen that when water is used as a ring-opening agent, products with low monomer residue and good thermal stability can only be obtained at high temperatures.

[0259] Test Example 14

[0260] The products obtained in Examples 3-5 were hot-pressed into thin films with a thickness of 200 μm, and their transmittance to ultraviolet light was tested. As shown in Figure 7, the transmittance of the films obtained in Examples 3-5 at a wavelength of 300 nm is almost 0, and they can be used as anti-ultraviolet materials.

[0261] Test Example 15

[0262] The products obtained in Examples 1-5 were subjected to fluorescence performance testing. The modified polylysine obtained in Example 1 had a fluorescence peak corresponding to an excitation wavelength of 420-460 nm and an emission wavelength of 490-520 nm. The modified polylysine obtained in Example 2 had a fluorescence peak corresponding to an excitation wavelength of 430-470 nm and an emission wavelength of 530-570 nm. As shown in Figure 8, the modified polylysine obtained in Example 3 had a fluorescence peak corresponding to an excitation wavelength of 440-510 nm and an emission wavelength of 550-590 nm. The modified polylysine obtained in Example 4 had a fluorescence peak corresponding to an excitation wavelength of 450-510 nm and an emission wavelength of 560-600 nm. The modified polylysine obtained in Example 5 had a fluorescence peak corresponding to an excitation wavelength of 460-520 nm and an emission wavelength of 600-640 nm. Therefore, the modified polylysine obtained in Examples 1-5 exhibits fluorescence properties and can be used in the fields of fluorescent and optical anti-counterfeiting materials.

[0263] Test Example 16

[0264] The surface resistance of the modified polylysine obtained in Example 5 was tested, and its surface resistance was 8 × 10⁻⁶. 11 Ω can be used as a static dissipative material.

[0265] Test Example 17

[0266] The antibacterial properties of the modified polylysine obtained in Examples 1-32 and Comparative Examples 1-8 were tested, and the results are shown in Table 5.

[0267] The products obtained in Examples 4, 5, 14-21, Comparative Examples 3, 6, and 7 were subjected to cytotoxicity tests, and the results are shown in Figure 9 and Table 5. The IC50 values ​​of the products obtained in Examples 4, 5, and 14-21 were [not specified in the original text]. 50 The polymer concentration (corresponding to 50% relative cell activity, or 50% inhibition concentration) is greater than 1.5 mg / mL, indicating that the modified polylysine disclosed herein has low cytotoxicity.

[0268] It is evident that the modified polylysine of the present invention not only has a high antibacterial rate but also low cytotoxicity.

[0269] The products obtained from Comparative Examples 1, 2, 4, and 8 showed no significant antibacterial effect.

[0270] Table 5

[0271] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0272] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0273] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

A modified polylysine, characterized in that, The modified polylysine comprises linear repeat units and lysyl-based branched repeat units; wherein: 1) when the content of lysyl-based repeat units is < 4 wt%, the molar content of lysyl-based branched repeat units in the lysyl-based repeat units is < 20%, preferably > 1% and < 10%, based on the total amount of repeat units in the modified polylysine; 2) when the content of lysyl-based repeat units is > 4 wt% and < 10 wt%, the molar content of lysyl-based branched repeat units in the lysyl-based repeat units is < 50%, preferably > 0.10% and < 40%, based on the total amount of repeat units in the modified polylysine; and 3) when the content of lysyl-based repeat units is > 10 wt%, the molar content of lysyl-based branched repeat units in the lysyl-based repeat units is < 95%, preferably > 40% and < 90%, more preferably > 50% and < 90%, based on the total amount of repeat units in the modified polylysine. The modified polylysine of claim 1, wherein the branched repeat unit comprises one or more of Formula (I) - Formula (IV), and the linear repeat unit comprises one or more of Formula (V) - Formula (VI), In the formulae represents a chemical bond; wherein R1is selected from one or more of H, C 1-20 substituted or unsubstituted alkyl, C 3-20 substituted or unsubstituted cycloalkyl, C 6-20 substituted or unsubstituted aryl, C 5-20 substituted or unsubstituted heteroaryl; wherein each R2is independently selected from one or more of C 1-20 substituted or unsubstituted alkylene, C 3-20 substituted or unsubstituted cycloalkylene, C 6-20 substituted or unsubstituted arylene, C 5-20 substituted or unsubstituted heteroarylene. wherein R3, R4and R5are each independently selected from one or more of C 1-20 substituted or unsubstituted alkylene, C 3-20 substituted or unsubstituted cycloalkylene, C 6-20 substituted or unsubstituted arylene, C 5-20 substituted or unsubstituted heteroarylene. wherein the substituents of R1, R2, R3, R4and R5are each independently selected from one or more of C 1-10 alkyl, C 1-10 alkoxy; Preferably, wherein the branched repeat units comprise one or more of Formula (III) and Formula (IV), and the linear repeat units comprise one or more of Formula (V) and Formula (VI); or, preferably, wherein the branched repeat units comprise one or more of Formula (III) and Formula (IV), and the linear repeat units comprise Formula (V). The modified polylysine according to claim 1 or 2, wherein the molar content of lysyl-based branched repeat units in the ε-polymeric form is 40-80%, based on the total amount of lysyl-based branched repeat units in the modified polylysine; and / or wherein the molar content of lysyl-based branched repeat units is 0.01-70%, preferably 10-65%, based on the total amount of repeat units in the modified polylysine; and / or wherein the content of lysyl-based repeat units is 1 wt%-95 wt%, preferably 10 wt%-95 wt%, more preferably 15 wt%-90 wt%, based on the total amount of repeat units in the modified polylysine. The modified polylysine according to any one of claims 1-3, wherein the content of lysyl-based repeat units is 15 wt%-90 wt%, based on the total amount of repeat units in the modified polylysine; wherein the proportion of lysyl-based branched repeat units in the lysyl-based repeat units is > 50% and < 90%; wherein the molar content of lysyl-based branched repeat units in the ε-polymeric form is 40-80%, based on the total amount of lysyl-based branched repeat units in the modified polylysine; and wherein the branched repeat units comprise one or more of Formula (III) and Formula (IV), and the linear repeat units comprise Formula (V). The modified polylysine according to any one of claims 1-4, wherein the linear repeat units further comprise one or more of the following linear repeat units: -HN(CH2)4CH(N(R1)(R2R’))CO-, -R2(R1)NCH((CH2)4NH2)CO-, -HN(CH2)4CH(N(R2R’)(R2R’))CO-, -R2((R2R’))NCH((CH2)4NH2)CO-, -HN(CH2)4CH(NHR1)CO-, and -(R1)NCH((CH2)4NH2)CO-. Preferably, the linear repeat units further comprise one or two of the following linear repeat units: -HN(CH2)4CH(NHR1)CO- and -(R1)NCH((CH2)4NH2)CO-. The modified polylysine according to any one of claims 1-5, wherein The mass content of insoluble substances in the modified polylysine is <3%, preferably less than <1%, more preferably less than <0.5%; and / or The mass content of residual monomers in the modified polylysine is <15%; and / or The branching degree of the modified polylysine is 0.05-0.7, preferably 0.15-0.65; and / or The relative viscosity of the modified polylysine at 25°C is 1.2-5.0; and / or The weight average molecular weight of the modified polylysine is 100-150 thousand; and / or The molecular weight distribution of the modified polylysine is 1.2-2.5; and / or The hydrodynamic diameter of the modified polylysine is 50 nm-1000 nm, preferably 50 nm-700 nm. The modified polylysine according to any one of claims 2-6, wherein, R1is selected from one or more of H, C 1-15 substituted or unsubstituted alkyl, C 3-15 substituted or unsubstituted cycloalkyl, C 6-15 substituted or unsubstituted aryl, C 5-15 substituted or unsubstituted heteroaryl, preferably R1is selected from H, C 1-6 substituted or unsubstituted alkyl, C 3-8 substituted or unsubstituted cycloalkyl, C 6-10 substituted or unsubstituted aryl, C 5-10 substituted or unsubstituted heteroaryl, and wherein the substituents of R1are selected from one or more of C 1-5 substituted or unsubstituted alkyl, C 1-5 substituted or unsubstituted alkoxy; preferably, R1is selected from one or more of H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted phenyl, substituted or unsubstituted furanyl, and wherein the substituents of R1are selected from one or more of methyl, ethyl, propyl, butyl, ethoxy and propoxy; wherein R2is selected from one or more of substituted or unsubstituted alkylene, C 1-15 substituted or unsubstituted cycloalkylene, C 3-15 substituted or unsubstituted cycloalkylene, C 6-15 substituted or unsubstituted arylene, C 5-15 substituted or unsubstituted heteroarylene, preferably R2is selected from one or more of substituted or unsubstituted methylene, substituted or unsubstituted ethylene, substituted or unsubstituted propylene, substituted or unsubstituted butylene, substituted or unsubstituted pentylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, substituted or unsubstituted furanylene, and wherein the substituents of R2are selected from one or more of alkyl, C 1-6 substituted or unsubstituted cycloalkylene, C 3-8 substituted or unsubstituted cycloalkylene, C 6-10 substituted or unsubstituted arylene, C 5-10 substituted or unsubstituted heteroarylene, and wherein the substituents of R2are selected from one or more of alkyl, C 1-5 substituted or unsubstituted cycloalkylene, C 1-5 substituted or unsubstituted cycloalkylene, C ; preferably, R2is selected from one or more of substituted or unsubstituted methylene, substituted or unsubstituted ethylene, substituted or unsubstituted propylene, substituted or unsubstituted butylene, substituted or unsubstituted pentylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, substituted or unsubstituted furanylene, and wherein the substituents of R2are selected from one or more of methyl, ethyl, propyl, butyl, ethoxy, and propoxy; wherein R3is selected from one or more of substituted or unsubstituted alkylene, C 2-12 substituted or unsubstituted cycloalkylene, C 3-15 substituted or unsubstituted cycloalkylene, C 6-15 substituted or unsubstituted arylene, C 5-15 substituted or unsubstituted heteroarylene, preferably R3is selected from one or more of C 2-11 substituted or unsubstituted alkylene, C 3-8 substituted or unsubstituted cycloalkylene, C 6-10 substituted or unsubstituted arylene, C 5-10 substituted or unsubstituted heteroarylene, and wherein the substituents of R3are selected from one or more of C 1-5 substituted or unsubstituted alkyl, C 1-5 substituted or unsubstituted alkoxy; preferably, R3is selected from one or more of ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, and wherein the substituents of R3are selected from one or more of methyl, ethyl, propyl, and butyl; and Among them, R4 and R5 are each independently selected from C. 1-18 Substituted or unsubstituted alkylene, C 3-18 Substituted or unsubstituted cycloalkylene, C 6-18 Substituted or unsubstituted aromatic groups and C 5-20 One or more of substituted or unsubstituted heteroaryl groups, preferably R4 and R5 each independently selected from C 1-12 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups and C 5-10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituents R4 and R5 are each independently selected from C 1-5 alkyl, C 1-5 One or more of the alkoxy groups; preferably, R4 and R5 are each independently selected from one or more of ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, substituted or unsubstituted furanylene, and wherein the substituents of R4 and R5 are each independently selected from one or more of methyl, ethyl, propyl and butyl. A method for preparing a modified polylysine, characterized in that, The method comprises: polymerizing the cyclic lysine monomer and the nylon monomer in the presence of a reaction aid under an inert atmosphere to prepare the modified polylysine; The reaction aid is selected from amino acids; The nylon monomer comprises one or more of lactam compounds and nylon salts; The cyclic lysine monomer has the structure shown in formula (1) below, the lactam compound has the structure shown in formula (2) below, and the nylon salt has the structure shown in formula (3) below, [ + H3NR5NH3 +- OOCR4COO - ] formula (3),​ One of L1 and L2 is H and the other is R1; or, one of L1 and L2 is -R2-R’ and the other is R1; or, L1 and L2 are independently -R2-R’; wherein R1is selected from H, C 1-20 substituted or unsubstituted alkyl, C 3-20 substituted or unsubstituted cycloalkyl, C 6-20 substituted or unsubstituted aryl, and C 5-20 substituted or unsubstituted heteroaryl; wherein each R2is independently selected from the group consisting of C 1-20 substituted or unsubstituted alkylene, C 3-20 substituted or unsubstituted cycloalkylene, C 6-20 substituted or unsubstituted arylene, and C 5-20 substituted or unsubstituted heteroarylene; Each R’ is independently selected from carboxyl, amine, amide, hydroxyl, isocyanate, and aldehyde groups; The modified polylysine according to any one of claims 1-5, wherein R3, R4and R5are each independently selected from C 1-20 substituted or unsubstituted alkylene, C 3-20 substituted or unsubstituted cycloalkylene, C 3-20 substituted or unsubstituted arylene, and C 5-20 substituted or unsubstituted heteroarylene; and wherein the substituents of R1, R2, R3, R4and R5are each independently selected from one or more of C 1-10 alkyl, C 1-5 alkoxy. The method of claim 8, wherein, R1is selected from one or more of H, C 1-15 substituted or unsubstituted alkyl, C 3-15 substituted or unsubstituted cycloalkyl, C 6-15 substituted or unsubstituted aryl, C 5-15 substituted or unsubstituted heteroaryl, preferably R1is selected from H, C 1-6 substituted or unsubstituted alkyl, C 3-8 substituted or unsubstituted cycloalkyl, C 6-10 substituted or unsubstituted aryl, C 5-10 substituted or unsubstituted heteroaryl, and wherein the substituents of R1are selected from one or more of C 1-5 substituted or unsubstituted alkyl, C 1-5 substituted or unsubstituted alkoxy; preferably, R1is selected from one or more of H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted phenyl, substituted or unsubstituted furanyl, and wherein the substituents of R1are selected from one or more of methyl, ethyl, propyl, butyl, ethoxy and propoxy; wherein R2is selected from one or more of substituted or unsubstituted alkylene, C 1-15 substituted or unsubstituted cycloalkylene, C 3-15 substituted or unsubstituted cycloalkylene, C 6-15 substituted or unsubstituted cycloalkylene, C 5-15 substituted or unsubstituted cycloalkylene, C 1-6 substituted or unsubstituted cycloalkylene, C 3-8 substituted or unsubstituted cycloalkylene, C 6-10 substituted or unsubstituted cycloalkylene, C 5-10 substituted or unsubstituted cycloalkylene, C 1-5 substituted or unsubstituted cycloalkylene, C 1-5 substituted or unsubstituted cycloalkylene, C ; preferably, R2is selected from one or more of substituted or unsubstituted methylene, substituted or unsubstituted ethylene, substituted or unsubstituted propylene, substituted or unsubstituted butylene, substituted or unsubstituted pentylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, substituted or unsubstituted furanylene, and wherein the substituents of R2are selected from one or more of methyl, ethyl, propyl, butyl, ethoxy, and propoxy; Among them, R3 is selected from C 2-12 Substituted or unsubstituted alkylene, C 3-15 Substituted or unsubstituted cycloalkylene, C 6-15 Substituted or unsubstituted aromatic groups, C 5-15 One or more of substituted or unsubstituted heteroaryl groups, preferably R3 selected from C 2-11 Substituted or unsubstituted alkylene, C 3-8 Substituted or unsubstituted cycloalkylene, C 6-10 Substituted or unsubstituted aromatic groups, C 5-10 One or more of substituted or unsubstituted heteroaryl groups, wherein the substituent of R3 is selected from C 1-5 alkyl and C 1-5 One or more of the alkoxy groups; preferably, R3 is selected from one or more of ethylidene, propylidene, butylidene, pentylidene, hexylidene, heptylidene, octylidene, nonylidene, decylidene, and undecylidene, and wherein the substituent of R3 is selected from one or more of methyl, ethyl, propyl, and butyl; and wherein R4and R5are each independently selected from one or more of substituted or unsubstituted alkylene, C 1-18 substituted or unsubstituted cycloalkylene, C 3-18 substituted or unsubstituted cycloalkylene, C 6-18 substituted or unsubstituted cycloalkylene, C 5-20 substituted or unsubstituted cycloalkylene, C 1-12 substituted or unsubstituted cycloalkylene, C 3-8 substituted or unsubstituted cycloalkylene, C 6-10 substituted or unsubstituted cycloalkylene, C 5-10 substituted or unsubstituted cycloalkylene, C 1-5 substituted or unsubstituted cycloalkylene, C 1-5 substituted or unsubstituted cycloalkylene, C ; preferably, R4and R5are each independently selected from one or more of ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, substituted or unsubstituted cyclopentylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted phenylene, substituted or unsubstituted furanylene, and wherein the substituents of R4and R5are each independently selected from one or more of methyl, ethyl, propyl, and butyl. The method according to claim 8 or 9, wherein said lactam compound is C 4-15 lactam, preferably one or more selected from the group consisting of butyrolactam, valerolactam, caprolactam, enantholactam, caprylolactam, pelargolactam, caprinolactam, undecanolactam, laurolactam and tridecanolactam; more preferably caprolactam; and / or The nylon salt is one or more selected from the group consisting of nylon 46 salt, nylon 4T salt, nylon 56 salt, nylon 5T salt, nylon 66 salt, nylon 6T salt, nylon 6I salt, nylon 610 salt, nylon 612 salt, nylon MXD6 salt, nylon 9T salt, nylon 910 salt, nylon 912 salt, nylon 1010 salt, nylon 10T salt, nylon 1012 salt, nylon 1212 salt, nylon 12T salt, nylon PACM6 salt, nylon PACMT salt, nylon PACMI salt, nylon MACMT salt, and nylon MACMI salt; preferably, the nylon salt is one or more selected from the group consisting of nylon 66 salt, nylon 56 salt, nylon 6T salt, nylon MXD6 salt, nylon 9T salt, and nylon 10T salt; further preferably, the nylon salt is one or more selected from the group consisting of nylon 66 salt, nylon 6T salt, and nylon MXD6 salt; and / or The cyclic lysine monomer is selected from the group consisting of compounds represented by formula (1) in which one of L1 and L2 is H and the other is R1; preferably, the cyclic lysine monomer is one or more selected from the group consisting of α-amino-ε-caprolactam, α-(N-methyl)amino-ε-caprolactam, α-(N-ethyl)amino-ε-caprolactam, α-(N-propyl)amino-ε-caprolactam, α-(N-butyl)amino-ε-caprolactam, and α-(N-benzyl)amino-ε-caprolactam. The method of any one of claims 8-10, wherein, The content of the cyclic lysine monomer in the total amount of monomers is 1 wt% to 95 wt%, preferably 10 wt% to 95 wt%, more preferably 15 wt% to 90 wt%; and the mass ratio of the cyclic lysine monomer to the nylon monomer is 1:99 to 95:5, preferably 10:90 to 95:5, more preferably 15:85 to 90:10; and / or wherein one of L1and L2is H and the other is R1, and R1is selected from the group consisting of H, C 1-20 substituted or unsubstituted alkyl, C 3-20 substituted or unsubstituted cycloalkyl, C 6-20 substituted or unsubstituted aryl, and C 5-20 substituted or unsubstituted heteroaryl; preferably, R1is selected from the group consisting of H, substituted or unsubstituted C 1-5 alkyl, and C 6-10 substituted or unsubstituted aryl; more preferably, R1is selected from the group consisting of H, methyl, ethyl, propyl, butyl, benzyl, and phenyl. The method of any one of claims 8-11, wherein, The reaction aid is one or more selected from the group consisting of aminobutyric acid, aminopentanoic acid, aminohexanoic acid, aminohexanoic acid, aminooctanoic acid, and arginine, more preferably aminohexanoic acid; and / or The content of the reaction aid in the total mass of reactants is 0.5% to 10%, preferably 2% to 6%; and / or In the method, no anionic polymerization catalyst, water, and acid are added. The method of any one of claims 8-12, wherein, The inert atmosphere includes one or more of nitrogen, helium, and argon; and / or The conditions of the polymerization reaction include a polymerization temperature of 70 to 280°C, preferably 100 to 270°C, further preferably 140 to 260°C, more preferably 140 to 250°C; a time of 0.5 to 24 h, preferably 4 to 14 h; and a pressure of 0 to 1.5 MPa, preferably 0.2 to 0.6 MPa; and / or The conditions of the polymerization reaction include stirring. The method of any one of claims 8-13, wherein, The polymerization reaction includes a first polymerization stage and a second polymerization stage; The conditions of the first polymerization stage include a temperature of 100 to 210°C, preferably 140 to 200°C, and a time of 1 to 8 h, preferably 2 to 4 h; and The conditions of the second polymerization stage include a temperature of 200 to 280°C, preferably 200 to 260°C, and a time of 1 to 9 h, preferably 1 to 4 h. The method of any one of claims 8-14, wherein, The method further comprises: after the polymerization reaction is performed, depressurizing the reaction system, and continuing the reaction of the reaction system under a second pressure; wherein the second pressure is 0.0 to -0.1 MPa, preferably 0.0 to -0.09 MPa, and the reaction time under the second pressure is 0.5-16 h, preferably 0.5-10 h. The method according to any one of claims 8-15, wherein the modified polylysine is the modified polylysine according to any one of claims 1-7. A composition comprising the modified polylysine according to any one of claims 1-7; preferably, the composition is in the form of a dispersion, a powder, a wire, a fiber, a film, a coating, a sheet, a plate, a profile, a porous material, or a gel material. Use of the modified polylysine according to any one of claims 1-7 as an antibacterial agent. The use according to claim 18, wherein the antibacterial rate of the modified polylysine against E. coli is 90.0% or more, preferably 99.0% or more, more preferably 99.9% or more; and / or The antibacterial rate of the modified polylysine against S. aureus is 90.0% or more, preferably 99.0% or more, more preferably 99.9% or more; and / or The survival rate of NIH 3T3 cells in a neutral phosphate buffer solution of the modified polylysine at a concentration of 1.5 mg / ml is higher than 50%. The use according to claim 18 or 19, wherein The modified polylysine is used as an antibacterial agent in a solid state; or The modified polylysine is used as an antibacterial agent after being dissolved in a solvent; preferably, the solvent is selected from one or more of water, alcohols, esters, ethers, furans, ketones, and hydrocarbon solvents, preferably one or more of water, ethanol, ethyl acetate, tetrahydrofuran, acetone, and cyclohexane. Use of the modified polylysine according to any one of claims 1-7 in an optical material; preferably, the transmittance of the modified polylysine at a 300 nm UV wavelength is 60% or less; and / or the fluorescence excitation wavelength of the modified polylysine is between 200-650 nm, and the emission wavelength is between 400-800 nm. Use of the modified polylysine according to any one of claims 1-7 and claim 16 as an antistatic agent, an adhesive, a caulking agent, a water treatment agent, a drug carrier, a cement water-reducing agent, an ink, a fabric finishing agent, or a fiber coloring agent.

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