A method for synthesizing cationic hyperbranched polymers with controllable degree of branching

Abstract

The application discloses a synthesis method of cationic hyperbranched polymers with controllable branching degree, and belongs to the field of high polymer materials. The method comprises the following steps: firstly, synthesizing an azide-diaalkynyl type AB2 monomer with controllable cation density; and then synthesizing a cationic hyperbranched polymer through a copper-catalyzed azide-alkyne click reaction. The influence of charge repulsion in the polymerization process is controlled by regulating the distance of cations in the monomer, so that the branching degree of the polymer is controlled. The synthesis method has the advantages of mild reaction conditions, high yield and yield, and can design and control the molecular weight and branching degree of the synthesized cationic hyperbranched polymer, and has potential and wide application value in the fields of biological medicine, functional materials and the like.

Description

Technical Field

[0001] This invention belongs to the field of polymer material synthesis, and specifically relates to a method for synthesizing cationic hyperbranched polymers with controllable branching degree. Background Technology

[0002] Hyperbranched polymers are highly branched three-dimensional macromolecules. They possess abundant terminal functional groups, making them easily modifiable and beneficial for synthesizing diverse functional materials. Furthermore, their highly branched molecular structure endows them with a variety of unique functions. Introducing cations into the hyperbranched polymer structure can impart unique properties such as hydrophilicity. They also exhibit advantages such as easier DNA encapsulation and lower toxicity compared to linear or dendritic cationic polymers with regular structures, making them significant advantages in targeted drug delivery and cell transfection. Therefore, the topologically controlled synthesis of hyperbranched polymers has strong application value.

[0003] However, current common hyperbranched polymer synthesis schemes generally struggle to precisely control the degree of branching without significantly altering polymer functionality and main chain structure. Typically, controlling branching through structural design requires introducing additional groups or side chains into the monomer, adjusting the monomer's reactivity or steric hindrance to control the degree of branching. For example, a literature report (10.1039 / c5py00307e) suggests controlling the degree of branching by adjusting the electronegativity of reactive groups, but this significantly alters the polymer's molecular weight and polydispersity, while also changing the chemical activity of the terminal groups, making independent design of the branching parameter difficult. Therefore, designing a series of homologous monomers and synthesis methods to achieve independent control of branching without significantly affecting other polymer structural parameters and properties, and enabling wider application in scenarios requiring precise branching design, has significant scientific value and application potential. Summary of the Invention

[0004] To address the problems in existing technologies, this invention provides a method for synthesizing cationic hyperbranched polymers with controllable branching degree. While maintaining the molecular weight, end-group reactivity, and other properties of the resulting hyperbranched polymer essentially unchanged, the branching degree—a parameter of the polymer—is independently designed and controlled. This method allows for independent and precise regulation of the polymer's branching degree, which is beneficial for applications such as drug delivery and gene transfection.

[0005] To achieve the objective of this invention, the following technical solution is adopted: a method for synthesizing a cationic hyperbranched polymer with controllable branching degree, comprising the following steps: (1) .

[0007] 1-Bromo-2-bromomethyl-3-hydroxypropane was dissolved in an organic solvent, and an excess of an amine compound was added. The mixture was stirred and reacted for 4-12 hours. The excess amine compound and solvent were removed by rotary evaporation to obtain intermediate 1. The concentration of the 1-bromo-2-bromomethyl-3-hydroxypropane was 0.05-0.5 mol / L, and the concentration of the amine compound was 0.1-1.5 mol / L, and not less than twice the concentration of the 1-bromo-2-bromomethyl-3-hydroxypropane. (2) .

[0009] The intermediate 1 obtained in step (1) is dissolved in a strongly polar solvent, and excess bromopropyne is added. The mixture is stirred for 4-12 hours, and intermediate 2 is obtained by precipitation in a precipitant. The concentration of intermediate 1 is 0.05-0.5 mol / L, and the concentration of bromopropyne is 0.1-1.5 mol / L and not less than twice the concentration of intermediate 1. (3)

[0011] .

[0012] The intermediate 2 obtained in step (2) is dissolved in a strongly polar solvent, and an excess of azide-amine compound is added. Under inert gas protection, a copper catalyst is added, and the reaction is stirred for 4 to 12 hours. Intermediate 3 is obtained by precipitation in a precipitant. The concentration of intermediate 2 is 0.05-0.5 mol / L, the concentration of the azide-amine compound is 0.1-1.5 mol / L and not less than twice the concentration of intermediate 2, and the amount of copper catalyst is 0.1-5 mg / ml. (4)

[0014] .

[0015] The intermediate 3 obtained in step (3) is dissolved in a strongly polar solvent, and excess bromopropyne is added. The mixture is stirred for 4-12 hours, and intermediate 4 is obtained by precipitation in a precipitant. The concentration of intermediate 3 is 0.05-0.5 mol / L, and the concentration of bromopropyne is 0.1-1.5 mol / L and not less than twice the concentration of intermediate 3. (5)

[0017]

[0018] The intermediate 4 obtained in step (4) is dissolved in an organic solvent, excess thionyl chloride is added, and the mixture is stirred for 4-12 hours. After removing the excess thionyl chloride by rotary evaporation, the residue is dissolved in water, excess sodium azide is added, and the mixture is heated to 80-95℃ and stirred for 12-72 hours. The product is precipitated in a precipitant, and the precipitate is dissolved in a strongly polar solvent and filtered. The filtrate is then precipitated with a precipitant to obtain a diynyl-azide monomer containing a cation. The concentration of intermediate 4 is 0.05-0.5 mol / L, the concentration of thionyl chloride is not greater than 1.5 mol / L and not less than twice the concentration of intermediate 4, and the concentration of sodium azide is not greater than 1.5 mol / L and not less than twice the concentration of intermediate 4.

[0019] (6) The diynyl-azido monomer containing cationic compounds obtained in step (5) is dissolved in a strongly polar solvent, and a copper catalyst is added under inert gas protection. The mixture is stirred for 1 to 12 hours, and then precipitated in a precipitant to obtain a cationic hyperbranched polymer with controllable branching degree. The concentration of the diynyl-azido monomer is 0.05-1 mol / L, and the amount of the copper catalyst is 0.1-5 mg / ml.

[0020] Further, the organic solvent mentioned in steps (1) and (5) is one or a mixture of tetrahydrofuran, dichloromethane, and trichloromethane.

[0021] Further, the amine compound mentioned in step (1) is one of dimethylamine, dimethylamine hydrate, and diethylamine.

[0022] Further, the strongly polar solvent mentioned in steps (2) to (6) is one or a mixture of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0023] Further, the precipitant mentioned in steps (2) to (6) is one or a mixture of diethyl ether, ethyl acetate, acetone, and tetrahydrofuran.

[0024] Further, the azido-amine compound mentioned in step (3) is one of dimethylazidoethylamine, dimethylazidopropylamine, dimethylazidobutylamine, dimethylazidopentylamine, dimethylazidohexylamine, dimethylazidoheptylamine, dimethylazidooctylamine, or a homologue whose main chain contains more methylene groups.

[0025] Furthermore, the copper catalyst mentioned in steps (3) and (6) is one of cuprous chloride, cuprous bromide, or elemental copper.

[0026] Furthermore, the inert gas mentioned in step (6) is one or a mixture of nitrogen and argon.

[0027] By selecting azide-amine raw materials containing varying numbers of methylene groups during monomer synthesis, the number of methylene groups separating two adjacent quaternary ammonium cationic groups in the monomer can be controlled, thereby regulating the spacing and density of the monomer cationic groups. During polymerization, the electrostatic repulsion between the polymer and monomer decreases with decreasing cationic density. This decrease in electrostatic repulsion makes the polymerization reaction more likely to occur on non-terminal groups, thus increasing the degree of branching of the polymer. Simultaneously, changes in the number of methylene groups have minimal impact on the electronegativity of the terminal groups, and the resulting steric hindrance changes are also small. Therefore, they have virtually no effect on the polymer molecular weight and the activity of the terminal groups, thus enabling independent design and control of the degree of branching.

[0028] The beneficial effects of this invention are as follows:

[0029] By fine-tuning the monomer structure, without significantly altering properties such as molecular weight, dispersibility, and end-group reactivity, the influence of charge repulsion during polymerization can be controlled by adjusting the monomer charge density, thus enabling the individual design and control of polymer branching.

[0030] The introduction of a controllable number of cationic groups into the hyperbranched polymer structure endows the polymer with unique properties such as hydrophilicity and strong polarity. Attached Figure Description

[0031] Figure 1 The image shows the 1H NMR spectrum of the diynyl-azido monomer containing a cation in Example 1.

[0032] Figure 2 The image shows the 1H NMR spectrum of the sample with a polymerization time of 1 hour in Example 1. Detailed Implementation

[0033] The following examples are provided to further illustrate the present invention and are intended to explain the invention, not to limit its scope. Unless otherwise specified, all figures are expressed in parts by weight and weight percentages.

[0034] Unless otherwise specified, the raw materials used in this invention are all conventional commercially available products; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0035] The hyperbranched polymer was analyzed by 1H NMR. The peaks at 3.8–4.4 g / cm³ were characteristic peaks of the alkynyl group, the multiplets at 8.5–9.0 g / cm³ were characteristic peaks of the triazole ring, and the peak at 1.5–2.0 g / cm³ was the sum of characteristic peaks of some methylene and methine hydrogen groups in the polymer, which is related to the number of methylene groups in the azide-amine structure. The degree of branching was calculated using the integral values ​​of these characteristic peaks. The molecular weight was obtained by gel permeation chromatography (GPC).

[0036] The embodiments of the present invention will be further described below with reference to several examples.

[0037] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0038] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0039] Example 1

[0040] (1) Add 0.005 mol of 1-bromo-2-bromomethyl-3-hydroxypropane, 25 ml of tetrahydrofuran, and 0.015 mol of dimethylamine to a 50 ml round-bottom flask. Stir the reaction for 4 hours and remove excess dimethylamine and tetrahydrofuran by rotary evaporation to obtain intermediate 1.

[0041] (2) Dissolve the obtained intermediate 1 in 25 ml of N,N-dimethylformamide, add 0.015 mol of bromopropyne, stir the reaction at room temperature for 4 hours, precipitate the system in diethyl ether, collect the solid by centrifugation, and obtain intermediate 2.

[0042] (3) Dissolve the obtained intermediate 2 in 25 ml of N,N-dimethylformamide, add 0.015 mol of dimethyl azidopropylamine, add 10 mg of cuprous bromide under inert gas protection, stir and react at room temperature for 4 hours, precipitate in diethyl ether, collect the solid by centrifugation, and obtain intermediate 3.

[0043] (4) The obtained intermediate 3 was dissolved in 25 ml of N,N-dimethylformamide, 0.015 mol of bromopropyne was added, and the mixture was stirred at room temperature for 12 hours. The mixture was then precipitated in diethyl ether, and the solid was collected by centrifugation to obtain intermediate 4.

[0044] (5) The obtained intermediate 4 was dissolved in 25 ml of dichloromethane, 0.01 mol of thionyl chloride was added, and the mixture was refluxed and stirred for 4 hours. After removing excess thionyl chloride by rotary evaporation, the residue was dissolved in water, 0.01 mol of sodium azide was added, and the mixture was heated to 85 °C and stirred for 72 hours. The product was precipitated in ethanol, and the precipitate was dissolved in N,N-dimethylformamide and filtered. The filtrate was precipitated with ethanol to obtain a diynyl-azide type monomer containing a cation.

[0045] (6) The obtained diynyl-azido monomer containing cations was dissolved in 25 ml of N,N-dimethylformamide. 10 mg of cuprous bromide was added under nitrogen and argon mixed gas protection. The mixture was stirred at room temperature for 5 hours. Samples were taken at intervals. The product was precipitated in diethyl ether to obtain a cationic hyperbranched polymer with controllable branching degree.

[0046] The nuclear magnetic resonance characterization of the obtained diynyl-azido monomer containing cations is as follows: Figure 1 As shown. The 1H NMR spectrum of the hyperbranched polymer obtained after reacting for 1 hour in step (6) is shown below. Figure 2 As shown in Table 1, the molecular weight and degree of branching of the obtained cationic hyperbranched polymers are presented.

[0047] Example 2

[0048] (1) Add 0.005 mol of 1-bromo-2-bromomethyl-3-hydroxypropane and 25 ml of chloroform to a 50 ml round-bottom flask, add 0.015 mol of dimethylamine, stir for 4 hours, remove excess dimethylamine and tetrahydrofuran by rotary evaporation, and obtain intermediate 1.

[0049] (2) Dissolve the obtained intermediate 1 in 25 ml of N,N-dimethylformamide, add 0.015 mol of bromopropyne, stir the reaction at room temperature for 4 hours, precipitate the system in diethyl ether, collect the solid by centrifugation, and obtain intermediate 2.

[0050] (3) Dissolve the obtained intermediate 2 in 25 ml of dimethyl sulfoxide, add 0.015 mol of dimethyl azidohexylamine, add 10 mg of cuprous bromide under inert gas protection, stir and react at room temperature for 4 hours, precipitate in diethyl ether, collect the solid by centrifugation, and obtain intermediate 3.

[0051] (4) The obtained intermediate 3 was dissolved in 25 ml of N,N-dimethylformamide, 0.015 mol of bromopropyne was added, and the mixture was stirred at room temperature for 8 hours. The solid was precipitated in ethyl acetate and collected by centrifugation to obtain intermediate 4.

[0052] (5) The obtained intermediate 4 was dissolved in 25 ml of chloroform, 0.01 mol of thionyl chloride was added, and the mixture was refluxed and stirred for 4 hours. After removing excess thionyl chloride by rotary evaporation, the residue was dissolved in water, 0.01 mol of sodium azide was added, and the mixture was heated to 85 °C and stirred for 72 hours. The product was precipitated in ethanol, and the precipitate was dissolved in N,N-dimethylformamide and filtered. The filtrate was precipitated with ethanol to obtain a diynyl-azide type monomer containing a cation.

[0053] (6) The obtained diynyl-azido monomer containing cations was dissolved in 25 ml of N,N-dimethylformamide, and 10 mg of elemental copper was added under argon protection. The mixture was stirred at room temperature for 10 hours. Samples were taken at intervals, and the product was precipitated in diethyl ether to obtain a cationic hyperbranched polymer with controllable branching degree.

[0054] The molecular weight and degree of branching of the obtained hyperbranched polymers are shown in Table 1.

[0055] Example 3

[0056] (1) Add 0.005 mol of 1-bromo-2-bromomethyl-3-hydroxypropane, 25 ml of tetrahydrofuran, and 0.015 mol of dimethylamine to a 50 ml round-bottom flask. Stir the reaction for 4 hours and remove excess dimethylamine and tetrahydrofuran by rotary evaporation to obtain intermediate 1.

[0057] (2) Dissolve the obtained intermediate 1 in 25 ml of N,N-dimethylformamide, add 0.015 mol of bromopropyne, stir the reaction at room temperature for 4 hours, precipitate the system in diethyl ether, collect the solid by centrifugation, and obtain intermediate 2.

[0058] (3) Dissolve the obtained intermediate 2 in 25 ml of N,N-dimethylformamide, add 0.015 mol of dimethyl azidodecylamine, add 10 mg of cuprous bromide under inert gas protection, stir and react at room temperature for 4 hours, precipitate in diethyl ether, collect the solid by centrifugation, and obtain intermediate 3.

[0059] (4) The obtained intermediate 3 was dissolved in 25 ml of N,N-dimethylformamide, 0.015 mol of bromopropyne was added, and the mixture was stirred at room temperature for 4 hours. The solid was precipitated in diethyl ether and collected by centrifugation to obtain intermediate 4.

[0060] (5) The obtained intermediate 4 was dissolved in 25 ml of dichloromethane, 0.01 mol of thionyl chloride was added, and the mixture was refluxed and stirred for 4 hours. After removing excess thionyl chloride by rotary evaporation, the residue was dissolved in water, 0.01 mol of sodium azide was added, and the mixture was heated to 85 °C and stirred for 72 hours. The product was precipitated in diethyl ether, and the precipitate was dissolved in N,N-dimethylformamide and filtered. The filtrate was precipitated with ethanol to obtain a diynyl-azide type monomer containing a cation.

[0061] (6) The obtained diynyl-azido monomer containing cations was dissolved in 25 ml of N,N-dimethylformamide, and 10 mg of cuprous chloride was added under nitrogen protection. The mixture was stirred at room temperature for 1 hour. Samples were taken at intervals, and the product was precipitated in diethyl ether to obtain a cationic hyperbranched polymer with controllable branching degree.

[0062] Table 1. Molecular weight and degree of branching of hyperbranched polymers

[0063]

[0064] As shown in Table 1, by fine-tuning the monomer structure (adding several methylene groups), it is possible to independently design and control the degree of branching without significant changes in polymerization time and number-average molecular weight. Furthermore, the added methylene groups do not substantially alter the electronegativity of the terminal groups, ensuring that the reactivity of the terminal groups in the product remains essentially unchanged. As the number of methylene groups in the monomer increases, the cation density of both the monomer and the polymer decreases, leading to a reduction in polymer charge repulsion and thus increasing the degree of branching.

[0065] Example 4

[0066] (1) In a 50 ml round-bottom flask, 0.05 mol / L of 1-bromo-2-bromomethyl-3-hydroxypropane was prepared using tetrahydrofuran as solvent. Dimethylamine hydrate was added to make the concentration of dimethylamine hydrate 0.1 mol / L. The mixture was stirred for 12 hours. Excess dimethylamine hydrate and tetrahydrofuran were removed by rotary evaporation to obtain intermediate 1.

[0067] (2) The obtained intermediate 1 was dissolved in N,N-dimethylformamide to make the concentration of intermediate 1 0.05 mol / L. Bromopropyne was added to make the concentration of bromopropyne 0.1 mol / L. The mixture was stirred at room temperature for 12 hours. The system was precipitated in diethyl ether. The solid was collected by centrifugation to obtain intermediate 2.

[0068] (3) Dissolve the obtained intermediate 2 in N,N-dimethylformamide to a concentration of 0.05 mol / L, add dimethyl azidodecylamine to a concentration of 0.1 mol / L, add cuprous bromide under inert gas protection to a concentration of 0.1 mg / ml, stir the reaction at room temperature for 12 hours, precipitate in diethyl ether, collect the solid by centrifugation, and obtain intermediate 3.

[0069] (4) The obtained intermediate 3 was dissolved in N,N-dimethylformamide to a concentration of 0.05 mol / L. Bromopropyne was added to a concentration of 0.1 mol / L. The mixture was stirred at room temperature for 12 hours, precipitated in diethyl ether, and the solid was collected by centrifugation to obtain intermediate 4.

[0070] (5) The obtained intermediate 4 was dissolved in dichloromethane to a concentration of 0.05 mol / L. Thionyl chloride was added to a concentration of 0.1 mol / L. The mixture was refluxed and stirred for 4 hours. After removing excess thionyl chloride by rotary evaporation, the residue was dissolved in water. Sodium azide was added to a concentration of 0.1 mol / L. The mixture was heated to 95°C and stirred for 12 hours. The product was precipitated in tetrahydrofuran. The precipitate was dissolved in N,N-dimethylformamide and filtered. The filtrate was precipitated with ethanol to obtain a diynyl-azide monomer containing a cation.

[0071] (6) The obtained diynyl-azido monomer containing cations was dissolved in N,N-dimethylformamide at a concentration of 0.05 mol / L. Cuprous bromide was added under argon protection to make its concentration 0.1 mg / ml. The reaction was stirred at room temperature for 5 hours. The product was precipitated in diethyl ether to obtain a cationic hyperbranched polymer with controllable branching degree.

[0072] Example 5

[0073] (1) In a 50 ml round-bottom flask, 0.5 mol / L of 1-bromo-2-bromomethyl-3-hydroxypropane was prepared using tetrahydrofuran as solvent. Diethylamine was added to make the concentration of diethylamine 1.5 mol / L. The mixture was stirred for 12 hours. Excess diethylamine and tetrahydrofuran were removed by rotary evaporation to obtain intermediate 1.

[0074] (2) The obtained intermediate 1 was dissolved in N,N-dimethylformamide to make the concentration of intermediate 1 0.5 mol / L. Bromopropyne was added to make the concentration of bromopropyne 1.5 mol / L. The mixture was stirred at room temperature for 8 hours. The system was precipitated in diethyl ether. The solid was collected by centrifugation to obtain intermediate 2.

[0075] (3) Dissolve the obtained intermediate 2 in dimethyl sulfoxide to a concentration of 0.5 mol / L, add dimethyl azidodecylamine to a concentration of 1.5 mol / L, add cuprous bromide under inert gas protection to a concentration of 5 mg / ml, stir the reaction at room temperature for 5 hours, precipitate in diethyl ether, collect the solid by centrifugation, and obtain intermediate 3.

[0076] (4) The obtained intermediate 3 was dissolved in N-methylpyrrolidone to a concentration of 0.5 mol / L. Bromopropyne was added to a concentration of 1.5 mol / L. The mixture was stirred at room temperature for 6 hours, precipitated in diethyl ether, and the solid was collected by centrifugation to obtain intermediate 4.

[0077] (5) The obtained intermediate 4 was dissolved in dichloromethane to a concentration of 0.5 mol / L. Thionyl chloride was added to a concentration of 1.5 mol / L. The mixture was refluxed and stirred for 4 hours. Excess thionyl chloride was removed by rotary evaporation. The residue was dissolved in water. Sodium azide was added to a concentration of 1.5 mol / L. The mixture was heated to 80°C and stirred for 72 hours. The product was precipitated in diethyl ether. The precipitate was dissolved in N,N-dimethylformamide and filtered. The filtrate was precipitated with ethanol to obtain a diynyl-azide monomer containing a cation.

[0078] (6) The obtained diynyl-azido monomer containing cations was dissolved in N,N-dimethylformamide at a concentration of 1 mol / L. Cuprous bromide was added under nitrogen protection to make its concentration 5 mg / ml. The mixture was stirred at room temperature for 12 hours. The product was precipitated in diethyl ether to obtain a cationic hyperbranched polymer with controllable branching degree.

[0079] The above embodiments describe in detail the structure, features, and effects of the present invention. The above description is only a preferred embodiment of the present invention. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall still fall within the scope of protection of the present invention if they do not exceed the scope covered by the specification.

Claims

1. A method for synthesizing cationic hyperbranched polymers with controllable degree of branching, characterized in that, The method comprises the following steps: (1) dissolving 1-bromo-2-bromomethyl-3-hydroxypropane in an organic solvent, adding an excess of an amine compound, stirring for 4-12 hours, and removing the excess amine compound and solvent by rotary evaporation to obtain intermediate 1; the concentration of the 1-bromo-2-bromomethyl-3-hydroxypropane is 0.05-0.5 mol / L, and the concentration of the amine compound is 0.1-1.5 mol / L and not less than 2 times the concentration of the 1-bromo-2-bromomethyl-3-hydroxypropane; (2) dissolving the intermediate 1 obtained in step (1) in a strong polar solvent, adding an excess of bromopropargyl, stirring for 4-12 hours, and precipitating in a precipitant to obtain intermediate 2; the concentration of the intermediate 1 is 0.05-0.5 mol / L, and the concentration of the bromopropargyl is 0.1-1.5 mol / L and not less than 2 times the concentration of the intermediate 1; (3) dissolving the intermediate 2 obtained in step (2) in a strong polar solvent, adding an excess of an azido-amine compound, adding a copper catalyst under inert gas protection, stirring for 4-12 hours, and precipitating in a precipitant to obtain intermediate 3; the concentration of the intermediate 2 is 0.05-0.5 mol / L, the concentration of the azido-amine compound is 0.1-1.5 mol / L and not less than 2 times the concentration of the intermediate 2, and the amount of the copper catalyst is 0.1-5 mg / ml; (4) dissolving the intermediate 3 obtained in step (3) in a strong polar solvent, adding an excess of bromopropargyl, stirring for 4-12 hours, and precipitating in a precipitant to obtain intermediate 4; the concentration of the intermediate 3 is 0.05-0.5 mol / L, and the concentration of the bromopropargyl is 0.1-1.5 mol / L and not less than 2 times the concentration of the intermediate 3; (5) dissolving the intermediate 4 obtained in step (4) in an organic solvent, adding an excess of thionyl chloride, stirring for 4-12 hours, dissolving the residue in water after removing the excess thionyl chloride by rotary evaporation, adding an excess of sodium azide, stirring at 80-95 ℃ for 12-72 hours, precipitating the product in a precipitant, dissolving the precipitate in a strong polar solvent, and filtering to obtain a diacetylenyl-azido type monomer containing a cation; the concentration of the intermediate 4 is 0.05-0.5 mol / L, the concentration of the thionyl chloride is not more than 1.5 mol / L and not less than 2 times the concentration of the intermediate 4, and the concentration of the sodium azide is not more than 1.5 mol / L and not less than 2 times the concentration of the intermediate 4; (6) dissolving the diacetylenyl-azido type monomer containing a cation obtained in step (5) in a strong polar solvent, adding a copper catalyst under inert gas protection, stirring for 1-12 hours, and precipitating in a precipitant to obtain a cationic hyperbranched polymer with controllable branching degree; the concentration of the diacetylenyl-azido type monomer is 0.05-1 mol / L, and the amount of the copper catalyst is 0.1-5 mg / ml.

2. The method of claim 1, wherein, The organic solvent is one or more of tetrahydrofuran, dichloromethane, and trichloromethane.

3. The method of claim 1, wherein, The amine compound in step (1) is one of dimethylamine, dimethylamine hydrate, and diethylamine. The amine compound in step (1) is one of dimethylamine, dimethylamine hydrate, and diethylamine.

4. The method of claim 1, wherein, The strong polar solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone.

5. The method of claim 1, wherein, The precipitant is one or more of diethyl ether, ethyl acetate, acetone, tetrahydrofuran.

6. The method of claim 1, wherein, The azido-amine compound in step (3) is one of dimethylazidoethylamine, dimethylazidopropylamine, dimethylazidobutylamine, dimethylazidopentylamine, dimethylazidohexylamine, dimethylazidoheptylamine, dimethylazidooctylamine.

7. The method of claim 1, wherein, The copper catalyst in steps (3) and (6) is one of cuprous chloride, cuprous bromide, elemental copper.

8. The method of claim 1, wherein, The inert gas in step (6) is one or a mixture of nitrogen, argon.

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