Preparation methods of ring-chain hybrid polymers and ring-chain hybrid polymers

Abstract

The application provides a preparation method of a ring-chain hybrid structure polymer and the ring-chain hybrid structure polymer. The preparation method comprises the following steps: obtaining a linear polymer precursor, the linear polymer precursor having a group A, a group B and a side group F, and the linear polymer precursor having a thioester bond structure; combining a compound D with at least part of the side groups F of the linear polymer precursor, so that at least part of the side groups of the linear polymer precursor are converted into charged groups; making the group A and the group B undergo a ring closing reaction, so that a cyclic polymer with a thioester bond structure and charged groups is formed; optionally removing the charged groups, so that a cyclic polymer is obtained; and making the cyclic polymer undergo a polymerization reaction by using the thioester bond structure, so that a ring-chain hybrid structure polymer is obtained. The reaction process of the preparation method is simple, the solid content is high, the by-products are few, the cost of the treatment and separation process of the product is low, and the method has great application value in industrial production.

Description

Technical Field

[0001] This invention relates to a method for preparing a ring-chain hybrid polymer and the ring-chain hybrid polymer, belonging to the field of polymer materials. Background Technology

[0002] In recent years, the hybridization of colloids and polymers has attracted widespread attention from the scientific community. Colloids, as particles ranging from 1 to 100 nm, exhibit excellent performance in acoustic, optical, electrical, magnetic, thermal, and catalytic functions, but their ability to assemble into superstructures and achieve functional coupling is insufficient. Polymer chains, on the other hand, possess rich chain composition and topological structures, the ability to assemble superstructures, and responsiveness. Combining them with colloids can achieve complementary advantages, leading to the creation of more novel materials. Currently, there are already studies and reports on the hybrid structures and properties of colloids and polymers.

[0003] In 2015, reference 1 reported a ball-chain hybrid structure constructed from oligomeric siloxane (POSS) molecular nanoparticles. This structure can achieve selective assembly to form a highly ordered supramolecular lattice. Furthermore, it possesses rich phase structures and sub-10 nm fine circuitry. This structural unit, described as a "giant atom," holds promise as a novel building block for materials.

[0004] However, due to the difficulty in preparing cyclic polymers, their topological structures have not been extensively studied. Using cyclic polymers as colloidal structural units and hybridizing them with polymer chains has become a challenging problem in the field. Preparing ring-chain hybrid structures allows for in-depth research into their physical and chemical properties and provides a basis for comparing their properties with other reported colloidal-polymer chain hybrid structures, which is of great scientific significance.

[0005] Therefore, researching a method for preparing a ring-chain hybrid polymer has become an urgent technical problem to be solved.

[0006] Reference 1: Stephen ZDCheng Macromolecules 2015, 48, 19, 7172-7179. Summary of the Invention

[0007] The problem the invention aims to solve

[0008] In view of the technical problems existing in the prior art, the present invention provides a method for preparing a ring-chain hybrid polymer. This method has a simple reaction process, high solid content, few by-products, and low cost for product processing and separation, making it of great application value in industrial production.

[0009] Solution for solving the problem

[0010] [1] A method for preparing a ring-chain hybrid polymer, comprising the following steps:

[0011] A linear polymer precursor is obtained, the linear polymer precursor having groups A, B and side groups F, and the linear polymer precursor having a thioester bond structure;

[0012] Compound D is combined with at least a portion of the side group F of the linear polymer precursor, thereby converting at least a portion of the side group of the linear polymer precursor into a charged group;

[0013] The group A and the group B undergo a ring-closing reaction to form a charged cyclic polymer with a thioester bond structure;

[0014] Optionally, the charged groups can be removed to obtain a cyclic polymer;

[0015] The cyclic polymer is polymerized using a thioester bond structure to obtain a cyclic-chain hybrid polymer.

[0016] [2] According to the preparation method described in [1] above, wherein the group A is selected from one or more combinations of azide, halogen, substituted or unsubstituted alkenyl or thiol groups; and / or,

[0017] The group B is selected from one or more combinations of substituted or unsubstituted alkynyl, ester, halogen, hydroxyl, substituted or unsubstituted amino, substituted or unsubstituted amide, substituted or unsubstituted alkenyl or mercapto groups; and / or

[0018] The side group F is selected from one or more combinations of carboxyl, amino, halogen, tertiary amine, pyridyl, and imidazole.

[0019] [3] According to the preparation method described in [1] or [2] above, the number average molecular weight of the linear polymer precursor is 5000g / mol-200000g / mol, preferably 10000g / mol-100000g / mol.

[0020] [4] The preparation method according to any one of [1]-[3] above, wherein the compound D comprises one or more combinations selected from carboxylic acid compounds, amino compounds, halogenated compounds, tertiary amine compounds, pyridine compounds, and imidazole compounds; and / or,

[0021] The compound D reacts with the linear polymer precursor via a quaternization reaction or a salt formation reaction, converting at least a portion of the side groups F of the linear polymer precursor into charged groups.

[0022] [5] The preparation method according to any one of [1]-[4] above, wherein the linear polymer precursor is given a thioester bond structure by using a chain transfer agent; preferably, the chain transfer agent includes a dithioester derivative or a trithioester derivative, more preferably, the dithioester derivative or trithioester derivative has one or more of a combination of hydroxyl, amino, halogen, ester group and carboxyl group.

[0023] [6] The preparation method according to any one of [1]-[5] above, wherein the closed-loop reaction includes one or more of click reaction, Staudinger reaction, and coupling reaction.

[0024] [7] The preparation method according to any one of [1]-[6] above, wherein the concentration of the linear polymer precursor in the preparation system is 0.1 to 300 mg / mL, preferably 10 to 100 mg / mL.

[0025] [8] The preparation method according to any one of [1]-[7] above, wherein the temperature of the ring-closing reaction is -80 to 100°C, preferably 25 to 80°C, and the time of the ring-closing reaction is 1 to 48 hours, preferably 3 to 36 hours.

[0026] [9] The preparation method according to any one of [1]-[8] above, wherein the ring-closing reaction is carried out in a solvent; preferably, the dielectric constant of the solvent is 2.2-49, more preferably 2.6-37.

[0027]

[10] A ring-chain hybrid polymer, which is prepared by the preparation method of the ring-chain hybrid polymer described in any one of [1]-[9] above, preferably, the diameter of the ring in the ring-chain hybrid polymer is 3-100 nm.

[0028] The effects of the invention

[0029] The method for preparing the ring-chain hybrid polymer of the present invention has a simple reaction process, high solid content, few by-products, and low cost for product processing and separation, and has great application value in industrial production. Attached Figure Description

[0030] Figure 1 The diagram shows a comparison of gel permeation chromatography (GPC) curves of linear polymer precursors (linear), cyclic polymers (cyclized), and ring-chain hybrid polymers (joints) of Example 3 of the present invention.

[0031] Figure 2The diagram shows a comparison of dynamic light scattering (DLS) data of linear polymer precursors (linear), cyclic polymers (cyclized), and ring-chain hybrid polymers (joints) in Example 3 of the present invention.

[0032] Figure 3 The image shown is a sample image of a ring-chain hybrid polymer observed under a transmission electron microscope according to Example 3 of the present invention. The ring-chain hybrid polymer was visualized by grafting PEO-CHO with Mn=1000. Detailed Implementation

[0033] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0034] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0035] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0036] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0037] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0038] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0039] In this instruction manual, the term "optional" indicates the use or omission of certain substances, components, procedures, application conditions, etc.

[0040] All unit names used in this manual are international standard unit names, and unless otherwise stated, the "%" used refers to weight or mass percentage content.

[0041] In this specification, "(meth)acrylic acid" refers to both acrylic acid and methacrylic acid. Furthermore, "(methyl)" throughout this specification has the same meaning.

[0042] In this specification, "halogen" refers to a "chlorine atom", "bromine atom", or "iodine atom".

[0043] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0044] This invention provides a method for preparing a ring-chain hybrid polymer, wherein the method uses a linear polymer precursor as a starting material. The method of preparing the ring-chain hybrid polymer of this invention features a simple reaction process, high solid content, few byproducts, and low cost for product processing and separation, making it of great application value in industrial production.

[0045] <Linear polymer precursors>

[0046] The linear polymer precursor of the present invention is formed by polymerization of polymer monomers. The present invention does not particularly limit the type of polymer monomers, as long as the linear polymer precursor formed after copolymerization has groups A, B, and side groups F, and the linear polymer precursor has a thioester bond structure. The thioester bond structure described in the present invention includes a dithioester structure or a trithioester structure, preferably a dithioester structure.

[0047] Specifically, in this invention, the polymer monomer can be one or a combination of two or more of (meth)acrylic acid monomers, (meth)acrylamide monomers, styrene monomers, and ethylene monomers.

[0048] For (meth)acrylic acid monomers, they may include (meth)acrylic acid or alkyl (meth)acrylic acid esters. Examples of alkyl (meth)acrylic acid esters include linear or branched alkyl (meth)acrylic acid esters with the alkyl group having 1 to 10 carbon atoms. Examples of the alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, etc.

[0049] For (meth)acrylamide monomers, they may include one or more combinations of (meth)acrylamide, N-methacrylamide, N,N-dimethylacrylamide, N-hydroxyethylacrylamide, N-hydroxymethylacrylamide, etc.

[0050] For styrene monomers, they may include styrene, substituted styrene, etc. For substituted styrene, the substituents may include alkyl, alkenyl, alkoxy, etc., wherein the alkyl, alkenyl, or alkoxy group preferably has 1-5 carbon atoms, and the alkyl, alkenyl, or alkoxy group may further contain substituents.

[0051] For ethylene monomers, they can include ethylene, propylene, isopropylene, butene, isobutene, pentene, isopentenene, butadiene, etc.

[0052] In some specific embodiments, the linear polymer precursor of the present invention may be obtained by polymerization of a monomer having a side group F, a monomer having a group A, and a monomer having a group B, wherein the group A and the group B are the same or different, and the group A, the group B and the side group F are different.

[0053] Side base F

[0054] For the side group F, it can be selected from one or more combinations of carboxyl, amino, halogen, tertiary amine, pyridyl, and imidazole groups.

[0055] The present invention does not specify the type of monomer containing the side group F, as long as it can copolymerize and has the aforementioned side group F. The present invention also does not specify the position of the side group F in the monomer; it can replace any feasible hydrogen in the monomer.

[0056] Specifically, in this invention, the monomer containing the side group F can be one or a combination of two or more of the following: (meth)acrylic acid monomers containing the side group F, (meth)acrylamide monomers containing the side group F, styrene monomers containing the side group F, and ethylene monomers containing the side group F.

[0057] In some specific implementations, the (meth)acrylic acid monomer with a carboxyl group as the side group F can be (meth)acrylic acid, carboxyethyl (meth)acrylic acid, carboxypentyl (meth)acrylic acid, etc.

[0058] In some specific implementations, styrene monomers with halogenated side groups F can be halogen-substituted C. 1-5 Alkyl-substituted styrene, halogen-substituted C 1-5 Alkenyl-substituted styrene, such as 4-chloromethylstyrene (VBC), 4-chloroethylstyrene, 4-bromomethylstyrene, 4-bromoethylstyrene, etc. Styrene monomers with an amino group as the side group F can be amino-substituted styrene monomers, preferably with the amino group protected by a protecting group, specifically a tert-butyloxycarbonyl group, such as tert-butyl 4-vinylphenylcarbamate (AStBoc).

[0059] In some specific implementations, the ethylene monomer with a pyridyl side group F can be 2-vinylpyridine, etc.

[0060] In some specific implementations, the ethylene monomer with imidazole side group F can be 2-vinylimidazole, etc.

[0061] In some specific embodiments, the (meth)acrylic monomer with a tertiary amine group F on the side group can be 2-aminoethyl methacrylate or a salt thereof, such as 2-aminoethyl methacrylate hydrochloride (AMA).

[0062] Group A

[0063] In this invention, group A can refer to the terminal group A of the linear polymer precursor. Group A can be one or a combination of two or more selected from azido, halogen, substituted or unsubstituted alkenyl, or thiol groups. Group A can be introduced directly using a monomer containing group A; for example, group A can be introduced using a halogen-containing monomer. Alternatively, group A can be introduced after obtaining the linear polymer via a substitution reaction, for example, by introducing an azido or thiol group after obtaining the linear polymer. Of course, in this invention, group A can also be introduced into the monomer first via a substitution reaction, followed by polymerization.

[0064] In this invention, the monomer containing group A can be one or a combination of two or more of the following: (meth)acrylic acid monomers containing group A, (meth)acrylamide monomers containing group A, styrene monomers containing group A, and ethylene monomers containing group A. The monomers containing group A and monomers containing side group F in this invention have the same range of options, but the monomers containing group A and monomers containing side group F are different. For example, when group A is halogen, side group F is not halogen.

[0065] In some specific embodiments, when group A is an azide group, it can be obtained by substituting a polymer unit with an azide salt, thereby initially giving the polymer unit an azide group. Preferably, the polymer unit has a halogen, which is replaced with an azide group by using an azide salt. In some specific embodiments, when group A is an azide group, a linear polymer can be obtained first, and then the linear polymer can be further substituting with an azide salt, thereby initially giving the linear polymer precursor an azide group.

[0066] In some specific embodiments, when group A is a thiol group, it can be obtained by reacting a thiol reagent with the polymer unit, thereby pre-concentrating a thiol group on the polymer unit. In some specific embodiments, when group A is a thiol group, a linear polymer can also be obtained first, and then the linear polymer can be reacted with a thiol reagent to obtain a linear polymer precursor that pre-concentrates a thiol group. Furthermore, in the presence of a thiol reagent, the linear polymer precursor can also directly undergo a ring-closing reaction.

[0067] In some specific implementations, for styrene monomers where group A is halogenated, it can be a halogen-substituted C. 1-5 Alkyl-substituted styrene, halogen-substituted C 1-5 Alkenyl-substituted styrene, such as 4-chloromethylstyrene (VBC), 4-chloroethylstyrene, 4-bromomethylstyrene, 4-bromoethylstyrene, etc.

[0068] In some specific implementations, for styrene monomers where group A is alkenyl, it can be 4-(3-enylbutyryl)styrene, 4-vinylstyrene, 4-propenylstyrene, etc.

[0069] Group B

[0070] In this invention, group B can refer to the terminal group B of a linear polymer precursor. In this invention, group A and group B can be the same or different. Group B can be selected from one or more combinations of substituted or unsubstituted alkynyl, ester, halogen, hydroxyl, substituted or unsubstituted amino, substituted or unsubstituted amide, and substituted or unsubstituted alkenyl groups. The alkynyl group can have 1-5 carbon atoms. Substituents can include alkyl, alkenyl, alkoxy, etc., preferably having 1-5 carbon atoms, and may further contain substituents.

[0071] In some specific implementations, for styrene monomers where group B is halogenated, C can be halogenated. 1-5 Alkyl-substituted styrene, halogen-substituted C 1-5 Alkenyl-substituted styrene, such as 4-chloromethylstyrene (VBC), 4-chloroethylstyrene, 4-bromomethylstyrene, 4-bromoethylstyrene, etc.

[0072] In some specific embodiments, since the (meth)acrylate alkyl ester monomer contains an ester group, the monomer having group B can be a (meth)acrylate alkyl ester monomer. Examples include (meth)acrylate alkyl esters that are linear or branched and have 1 to 10 carbon atoms in the alkyl group. Examples of the alkyl groups mentioned above include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, etc.

[0073] In some specific embodiments, group B is an alkynyl (meth)acrylate alkyl ester monomer, which may have at least one H in the above-mentioned (meth)acrylate alkyl ester monomer replaced by an alkynyl group. In addition, the alkynyl group of the present invention may be protected by a protecting group, specifically by a trimethylsilyl group, for example: 3-trimethylsilylpropynyl methacrylate.

[0074] In some specific embodiments, group B is an amino group of (meth)acrylate alkyl ester monomers, which may have at least one H in the above (meth)acrylate alkyl ester monomers replaced by an amino group, for example: 2-aminoethyl methacrylate or a salt thereof, such as 2-aminoethyl methacrylate hydrochloride (AMA).

[0075] In some specific embodiments, group B is a hydroxyl group in an alkyl methacrylate monomer, which may be at least one H in the above alkyl methacrylate monomers substituted with a hydroxyl group, for example: hydroxyethyl methacrylate.

[0076] In some specific embodiments, since the (meth)acrylamide monomer contains an amide group, the monomer having group B can be a (meth)acrylamide monomer. Specifically, it can include one or more combinations of (meth)acrylamide, N-methacrylamide, N,N-dimethylacrylamide, N-hydroxyethylacrylamide, N-hydroxymethylacrylamide, etc.

[0077] In some specific embodiments, when group B is a thiol group, it can be obtained by reacting a thiol reagent with the polymer unit, thereby pre-concentrating the polymer unit with a thiol group. In some specific embodiments, when group B is a thiol group, a linear polymer can also be obtained first, and then the linear polymer can be reacted with a thiol reagent to obtain the linear polymer precursor, thereby pre-concentrating the linear polymer precursor with a thiol group.

[0078] In some specific implementations, for styrene monomers with an alkenyl group B, it can be 4-(3-enylbutyryl)styrene, 4-vinylstyrene, 4-propenylstyrene, etc.

[0079] Polymerization reaction

[0080] The polymerization reaction of this invention can be obtained by solution polymerization. The polymerization methods include random copolymerization, alternating copolymerization, block copolymerization, etc.

[0081] The polymerization reaction of the present invention can be obtained by simultaneously polymerizing a monomer having a side group F, a monomer having a group A, and a monomer having a group B; or by first polymerizing a monomer having a side group F and a monomer having a group A, and then polymerizing it with a monomer having a group B; or by first polymerizing a monomer having a side group F and a monomer having a group B, and then polymerizing it with a monomer having a group A; or by using at least one polymer monomer without a side group F, a group A, or a group B to polymerize to obtain a linear polymer, and then introducing a side group F, a group A, or a group B through various feasible chemical reactions.

[0082] In some specific embodiments, the polymerization reaction includes polymerizing polymer monomers in a solvent in the presence of a chain transfer agent and an initiator to obtain a linear polymer precursor, such as through free radical polymerization. By using a chain transfer agent, the linear polymer precursor can be given a thioester bond structure.

[0083] The chain transfer agent, i.e., the reversible addition-fragmentation chain transfer radical polymerization (RAFT) agent, may include disulfide derivatives or trisulfide derivatives. Specifically, the disulfide derivative or trisulfide derivative has one or more of the following groups: hydroxyl, amino, halogen, ester, and carboxyl groups. Specifically, the chain transfer agent may be OH-RAFT, CPADB, or D-CPADB, with the following specific structural formula:

[0084]

[0085] The initiator can be selected from one or more of organic peroxides and azo compounds, wherein the organic peroxide is preferably benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, benzoyl tert-butyl peroxide, methyl ethyl ketone peroxide, dodecyl peroxide, tert-butyl peroxide, diisopropyl peroxide, etc.; and the azo compound is preferably azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovalerate, azobiscyclohexylformitrile, dimethyl azobisisobutyrate, etc.

[0086] The present invention does not particularly limit the solvent; it can be a commonly used organic solvent or water, preferably an organic solvent. Examples include ketones such as acetone, methyl ethyl ketone, dimethyl acetone, methyl isobutyl ketone, acetophenone, and N-methyl-2-pyrrolidone; ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; and amides such as N,N-dimethylformamide and N,N-dimethylacetamide.

[0087] The present invention does not impose particular limitations on the conditions of the polymerization reaction, and can select them as needed, as long as the desired linear polymer precursor can be obtained. Generally, the polymerization reaction can be carried out at a temperature of 50-100°C for 1-24 hours to obtain the polymerization product. The polymerization product is then separated to obtain the linear polymer precursor. The present invention does not impose particular limitations on the separation method, and can use commonly used separation methods in the art, such as using n-hexane to precipitate the linear polymer precursor and then separating it using a centrifuge. Preferably, the polymerization reaction is carried out in an oxygen-free environment, and generally, a freeze-evacuation-thawing cycle of 3 to 5 times can be used for deoxygenation.

[0088] In other specific embodiments, the present invention may also involve terminating the reaction using a chain transfer agent after obtaining the linear polymer, thereby giving the linear polymer precursor a thioester bond structure. Specifically, the polymer monomers are cationicly polymerized in a solvent in the presence of an initiating system to obtain the linear polymer precursor.

[0089] In some specific implementations, the initiation system may include an initiator and an activator.

[0090] The initiator can be a tertiary haloalkane, a benzyl haloalkane, an ether compound, an alcohol compound, an ester compound, etc. Specifically, the initiator includes one or a combination of two or more of 1-(4-methoxyphenyl)ethanol, tert-butylmethanol, methylphenylmethanol, diphenylmethanol, isopropylmethanol, etc.

[0091] The activator may specifically include Lewis acids. The Lewis acid is generally one or a combination of two or more of metal halides, organometal halides, or complexes thereof. Specifically, in this invention, Lewis acids include, but are not limited to, one or a combination of two or more of boron trifluoride, aluminum trichloride, zinc dichloride, titanium tetrachloride, tin tetrachloride, antimony trichloride, chromium tetrachloride, ferric trichloride, gallium trichloride, titanium tetrachloride, and alkyl aluminum chloride. The Lewis acid is preferably one or a combination of two or more of tin tetrachloride, boron trifluoride, and gallium trichloride.

[0092] In some specific embodiments, the initiation system further includes a stabilizer. Preferably, the stabilizer comprises one or more combinations selected from ester compounds, ether compounds, organic amine compounds, and proton traps.

[0093] In some specific embodiments, the stabilizer includes one or more combinations selected from ethyl acetate, diethyl ether, dioxane, 2,6-di-tert-butylpyridine, etc.

[0094] Furthermore, for ease of use, activator and stabilizer complexes can be used directly, such as boron trifluoride diethyl ether complexes.

[0095] The present invention does not impose particular limitations on the conditions for cationic polymerization, and the conditions can be selected as needed, as long as the desired linear polymer precursor can be obtained. Generally, the polymerization reaction can be carried out at a temperature of -90 to 50°C for 0.5 to 12 hours to obtain the polymerization product. The polymerization product is then separated to obtain the linear polymer precursor. The separation method is not particularly limited, and can be a commonly used separation method in the art, such as precipitating the linear polymer precursor with n-hexane and separating it using a centrifuge. Furthermore, a chain transfer agent is used to terminate the reaction of the linear polymer precursor, giving it a thioester bond structure. The chain transfer agent is the same as described above, and can be OH-RAFT, CPADB, or D-CPADB, etc. Additionally, the present invention does not impose particular limitations on the amount of linear polymer precursor used, and generally, an excess is required.

[0096] The linear polymer precursor with a thioester bond structure is then separated to obtain the linear polymer precursor. The present invention does not particularly limit the separation method; it can be a commonly used separation method in the art, such as precipitating the linear polymer precursor with n-hexane and separating it using a centrifuge, thereby obtaining the linear polymer precursor with a thioester bond structure.

[0097] In some specific embodiments, the number-average molecular weight of the linear polymer precursor can be 5,000-200,000 g / mol, preferably 10,000-100,000 g / mol.

[0098] <Preparation Methods for Ring-Chain Hybrid Polymers>

[0099] The method for preparing the ring-chain hybrid polymer of the present invention uses a linear polymer precursor having side groups F, group A, and group B as a starting material, and may include the following steps:

[0100] Compound D is combined with at least a portion of the side group F of the linear polymer precursor, thereby converting at least a portion of the side group F of the linear polymer precursor into a charged group;

[0101] The group A and the group B undergo a ring-closing reaction to form a charged cyclic polymer with a thioester bond structure;

[0102] Optionally, the charged groups can be removed to obtain a cyclic polymer;

[0103] The cyclic polymer is polymerized using a thioester bond structure to obtain a cyclic-chain hybrid polymer.

[0104] Charge the linear polymer precursor

[0105] Compound D is combined with at least a portion of the side group F of the linear polymer precursor, converting at least a portion of the side group F of the linear polymer precursor into a charged group. This invention converts the side group F of the linear polymer precursor into a charged group, thereby charging the polymer chain. In this process, the modification of the polymer chain to carry a charge induces repulsion between the polymer chains, and the magnitude of the interchain repulsion varies depending on the amount of charge. This repulsion effectively reduces side reactions occurring between molecular chains during cyclization, creating conditions for subsequent intramolecular reactions of groups A and B, thus enabling the preparation of products at high concentrations.

[0106] In some specific embodiments, the compound D reacts with the linear polymer precursor via a quaternization reaction or a salt-forming reaction, converting at least a portion of the side group F of the linear polymer precursor into a charged group. Taking a salt-forming reaction (acid-base reaction) as an example, the side group F of the linear polymer precursor is an acidic or basic group, while the compound D is correspondingly a base or acid (i.e., the reactive group of compound D that can react with the side group F is a basic or acidic group).

[0107] In some specific embodiments, the side group F is selected from one or more combinations of carboxyl, amino, halogen, tertiary amine, pyridyl, and imidazole groups.

[0108] Compound D can be any compound that has a side group F that can react with it to convert it into a charged group. For example, compound D includes one or more combinations selected from carboxylic acids, amino compounds, halogenated compounds, tertiary amines, pyridines, and imidazoles. Specifically, compound D can be trifluoroacetic acid, iodoethane, methylimidazolium, pyridine, etc.

[0109] Preferably, the combination of reactive groups of the side group F of the linear polymer precursor / compound D is selected from the following combinations: carboxyl / amino, amino / carboxyl, halogen / tertiary amine, halogen / pyridyl, halogen / imidazolyl, tertiary amine / halogen, pyridyl / halogen, imidazolyl / halogen.

[0110] Here, in the two groups separated by the symbol " / ", the group before the symbol " / " is the side group F of the linear polymer precursor, and the group after the symbol " / " is the reactive group of compound D.

[0111] Furthermore, a portion of the side group F in the linear polymer precursor can be converted into charged groups, while the remaining portion retains its side group F form; alternatively, all side group F can be converted into charged groups. In some specific embodiments, after the reaction of charging the linear polymer precursor is completed, the proportion of side group F converted into charged groups is 10% to 100 mol%, preferably 60% to 100 mol%, by molar percentage.

[0112] In some specific embodiments, the charging of the linear polymer precursor is carried out in a solvent. Specifically, the linear polymer precursor is dissolved in a solvent, and then compound D is added, optionally with stirring to carry out the reaction. The stirring time is not particularly limited in this invention, but is generally 10-60 min.

[0113] The present invention does not particularly limit the solvent, which can be a commonly used organic solvent or water in the art. Further, the dielectric constant of the solvent is 2.2-49, preferably 2.6-37. Preferably, the solvent is an organic solvent. Examples of organic solvents include ketones such as acetone, methyl ethyl ketone, dimethyl acetone, methyl isobutyl ketone, acetophenone, and N-methyl-2-pyrrolidone; ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; and amides such as N,N-dimethylformamide and N,N-dimethylacetamide.

[0114] Furthermore, the present invention does not particularly limit the reaction temperature for charging the linear polymer precursor, and it can be carried out at 10-50°C, for example at room temperature (15-25°C).

[0115] Furthermore, it should be noted that when preparing linear polymer precursors, if an azide or thiol group needs to be introduced into the linear polymer precursor, this can be done simultaneously with charging the linear polymer precursor, or the azide or thiol group can be introduced first, followed by charging the linear polymer precursor. Further, to improve reaction efficiency, it is preferable to introduce the azide group simultaneously with charging the linear polymer precursor. To further improve reaction efficiency, the linear polymer precursor can be charged first, followed by the introduction of the thiol group to simultaneously carry out the ring-closing reaction.

[0116] Closed-loop reaction

[0117] The group A and the group B undergo a ring-closing reaction to form a charged cyclic polymer with a thioester bond structure. Group A and group B are combinations of groups that can react with each other to form covalent bonds, and they can be the same or different.

[0118] Preferably, group A / group B is selected from the following combinations: azide / alkynyl, azide / ester, halogen / halogen, halogen / hydroxyl, halogen / amino, mercapto / alkenyl, mercapto / mercapto, alkenyl / mercapto, alkenyl / mercapto, alkenyl / alkenyl, etc.

[0119] In the group combination described here, one of the two groups separated by the symbol " / " is group A and the other is group B, and there is no restriction on the order of their appearance.

[0120] The present invention does not impose any particular limitations on the conditions for the ring-closing reaction, as long as the reaction is carried out under conditions that enable group A and group B to undergo a ring-closing reaction. For example, the ring-closing reaction can be carried out in the presence of a catalyst, or it can be carried out without the use of a catalyst.

[0121] In some specific implementations, the closed-loop reaction may include one or more of the following: click reaction, Staudinger reaction, and coupling reaction.

[0122] In one specific implementation, group A / group B is halogen / halogen. In this case, step (3) can be performed in the presence of a catalyst to prepare a charged cyclic polymer with a thioester bond structure through a coupling reaction.

[0123] In one specific implementation, group A / group B is azide / alkynyl. In this case, step (3) can be performed in the presence of a catalyst to prepare a charged cyclic polymer with a thioester bond structure via a click reaction.

[0124] In one specific implementation, group A / group B is an azide / ester group. In this case, step (3) can be performed in the presence of a catalyst, which can be used to prepare a charged cyclic polymer with a thioester bond structure by Staudinger reaction.

[0125] In one specific implementation, group A / group B is a halogen / hydroxyl group, which can be prepared by coupling reaction to obtain a charged cyclic polymer with a thioester bond structure.

[0126] In one specific embodiment, group A / group B is a halogen / amino group, which can be prepared by coupling reaction to obtain a charged cyclic polymer with a thioester bond structure.

[0127] In one specific embodiment, group A / group B is alkenyl / alkenyl, which can be prepared by click reaction using a thiol reagent to obtain a charged cyclic polymer with a thioester bond structure. The present invention does not particularly limit the thiol reagent, but commonly used thiol reagents such as 1,2-dimercaptoethane are also acceptable.

[0128] The present invention does not impose any particular limitation on the catalyst, and the catalyst can be selected according to the specific reaction. Specifically, the catalyst for the coupling reaction can be triphenylphosphine palladium and a carbonate, such as triphenylphosphine palladium and cesium carbonate; the catalyst for the Staudinger reaction can be triphenylphosphine; and the catalyst for the click reaction can be cuprous halide, such as cuprous bromide. Of course, the click reaction may also be performed without a catalyst.

[0129] In some specific embodiments, the concentration of the reactants in the closed-loop reaction system is 0.1 mg / mL to 300 mg / mL, preferably 10 to 100 mg / mL.

[0130] In some specific implementations, the temperature of the closed-loop reaction is 0–100°C, preferably 25–80°C, and the time of the closed-loop reaction is 1–48 hours, preferably 3–36 hours.

[0131] Remove the charged groups

[0132] Optionally, the charged groups can be removed to obtain a cyclic polymer. Depending on the need, the present invention can remove the charged groups and then use post-treatment methods such as precipitation and washing to obtain a cyclic polymer. Alternatively, the present invention can also leave the charged groups unremoved and simply use post-treatment methods such as precipitation and washing to obtain the charged cyclic polymer.

[0133] The present invention does not particularly limit the method for removing charged groups. Generally, when using an acidic compound D, an alkaline substance is used to remove it, and when using an alkaline compound D, an acidic substance can be used to remove it.

[0134] For example, when trifluoroacetic acid is used as compound D, saturated NaHCO3 washing can be used to remove charged groups.

[0135] Additionally, catalysts can be removed by washing with water or during precipitation. For example, triphenylphosphine palladium can be removed by precipitating cyclic polymers using heated cyclohexane. When cuprous bromide is used as a catalyst, copper ions can be removed by dialysis with water.

[0136] Preparation of ring-chain hybrid polymers

[0137] Finally, the cyclic polymer is polymerized using the thioester bond structure to obtain a cyclic-chain hybrid polymer.

[0138] The polymer monomers will not be described in detail here, but can be the polymer monomers mentioned above in this application. For example, one or more of (meth)acrylic acid monomers, (meth)acrylamide monomers, styrene monomers, and ethylene monomers.

[0139] The polymerization reaction is a reversible addition-fragmentation chain transfer polymerization reaction, also known as RAFT polymerization. The thioester bond structure can be used to polymerize the cyclic polymer to obtain a cyclic-chain hybrid polymer.

[0140] Specifically, the polymerization reaction can utilize a thioester bond structure and be carried out in a solvent using polymer monomers in the presence of an initiator. Specifically, this polymerization reaction is substantially the same as the polymerization reaction used in the preparation of linear polymer precursors according to this application.

[0141] The initiator, solvent, etc. will not be described in detail here, but can be the initiator, solvent, etc. mentioned above in this application.

[0142] <Ring-Chain Hybrid Polymers>

[0143] This invention also provides a ring-chain hybrid polymer, which is prepared by the method for preparing a ring-chain hybrid polymer according to the present invention. Preferably, the diameter of the rings in the ring-chain hybrid polymer is 3-100 nm. The diameter of the rings in the ring-chain hybrid polymer of the present invention can be obtained by ranging using a transmission electron microscope (TEM) and then determined with the assistance of dynamic light scattering (DLS).

[0144] Example

[0145] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0146] Example 1

[0147] 0.1 mmol of boron trifluoride diethyl ether complex, 0.1 mmol of 1-(4-methoxyphenyl)ethanol (MOPE), and 2 mL of dichloromethane were added to a 50 mL test tube. After stirring, the mixture was frozen, evacuated, and thawed three times to remove oxygen. 1 mmol of 4-(3-enylbutyryl)styrene (VSt) was added at 0 °C and reacted for 30 min. Then, 10 mmol of 4-chloromethylstyrene (VBC) was added and the reaction continued for 30 min. Finally, 1 mmol of 4-(3-enylbutyryl)styrene was added and the reaction continued for 30 min to obtain the first reaction product containing the linear polymer precursor.

[0148] The reaction was terminated by adding 10 mmol of the chain transfer reagent OH-RAFT to the first reaction product, which then gave the first reaction product a dithioester structure. The first reaction product with the dithioester structure was then precipitated in n-hexane, washed three times, and dried to obtain the linear polymer PVSt-b-PVBC-b-PVSt with the dithioester structure.

[0149] The linear polymer PVSt-b-PVBC-b-PVSt with the dithioester structure was placed in a test tube, and 5 mmol of 2-methylimidazole was added and stirred for 30 min to charge the linear polymer. Then, 1 mmol of 1,2-dimercaptoethane was added, and a ring-closing reaction was carried out at 40 °C for 24 h to obtain the second reaction product. The second reaction product was precipitated using n-hexane at 60 °C, which also removed the charged groups. After washing three times and drying, a cyclic polymer was obtained.

[0150] The above cyclic polymer was placed in a test tube, and 0.05 mmol of azobisisobutyronitrile (AIB), 10 mmol of styrene (St), and 2 mL of dioxane were added. After stirring until homogeneous, the mixture was subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was then carried out at 80 °C for 8 hours. After the reaction was completed, the reaction was terminated by cooling, yielding the third reaction product. The third reaction product was precipitated in n-hexane, washed three times, and dried to obtain the cyclic-chain hybrid polymer.

[0151] The chain transfer reagent OH-RAFT used has the following structural formula:

[0152]

[0153] Example 2:

[0154] In a 25 mL test tube, 10 mmol of methacrylic acid (MAA), 0.02 mmol of azobisisobutyronitrile (AIB), 0.1 mmol of chain transfer reagent D-CPADB, 0.2 mmol of 4-chloromethylstyrene, and 2 mL of dioxane were added and stirred until homogeneous. The mixture was then subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling, yielding the first reaction product. The first reaction product was precipitated in n-hexane, washed three times, and dried to obtain a pink linear polymer PVBC-b-PMAA-b-PVBC with a dithioester structure.

[0155] The pink linear polymer PVBC-b-PMAA-b-PVBC with a dithioester structure was placed in a test tube, and 1 mL of dimethylformamide was added. After dissolution, 2 mmol of methylimidazole was added, and the mixture was stirred for 30 min to charge the linear polymer. Then, 1% of triphenylphosphine palladium catalyst and 1% of cesium carbonate (based on the total mass of the reactants) were added, and the linear polymer was subjected to a coupling reaction at 80 °C for 12 h to achieve cyclization. After the coupling reaction was completed, the cyclic polymer was precipitated with n-hexane at 60 °C, which also removed the charged groups. The cesium carbonate was removed by washing with water, and the polymer was dried to obtain a cyclic polymer with a dithioester structure.

[0156] The above cyclic polymer was placed in a test tube, and 0.05 mmol of azobisisobutyronitrile, 10 mmol of 2-vinylpyridine (2VP), and 2 mL of dioxane were added. After stirring until homogeneous, the mixture was subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling to obtain the second reaction product. The second reaction product was precipitated in n-hexane, washed three times, and dried to obtain the cyclic-chain hybrid polymer.

[0157] The chain transfer reagent D-CPADB used has the following structural formula:

[0158]

[0159] Example 3

[0160] 1 mmol of methyl methacrylate (MMA), 0.02 mg of azobisisobutyronitrile (AISOB), 0.1 mmol of chain transfer reagent CPADB, 10 mmol of tert-butyl 4-vinylphenylcarbamate (AStBoc), and 2 mL of dioxane were added to a 50 mL test tube. The mixture was stirred thoroughly and then subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling, yielding the first reaction product. The first reaction product was precipitated in n-hexane, washed three times, and dried to obtain a pink linear polymer PMMA-b-PAStBoc with a dithioester structure.

[0161] The linear polymer PMMA-b-PAStBoc with a dithioester structure was placed in a test tube, and 0.02 mmol of azobisisobutyronitrile, 0.2 mmol of 4-chloromethylstyrene, and 2 mL of dioxane were added. After stirring until homogeneous, the mixture was subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was then carried out at 80 °C for 8 hours. After the reaction was completed, the reaction was terminated by cooling, yielding the second reaction product. The second reaction product was precipitated in n-hexane, washed three times, and dried to obtain the pink linear polymer PMMA-b-PAStBoc-b-PVBC with a dithioester structure.

[0162] The linear polymer PMMA-b-PAStBoc-b-PVBC with a dithioester structure was placed in a test tube, and 0.2 mmol of NaN3, 5 mmol of trifluoroacetic acid, and 1 mL of dimethylformamide were added. The reaction was carried out for 24 h to obtain the third reaction product. The third reaction product was precipitated in n-hexane, washed three times, and dried to obtain the linear polymer PMMA-b-PStNH2-b-PVBC with a dithioester structure, azide-terminated ends, and a charge.

[0163] The linear polymer PMMA-b-PStNH2-b-PVBC with a dithioester structure and charged terminal azide groups was placed in a test tube, dissolved in 1 mL of dimethylformamide, and then 0.2 mmol of triphenylphosphine catalyst was added. After stirring for 30 min, another 0.6 mmol of triphenylphosphine catalyst was added and the mixture was heated to 40 °C to carry out the Staudinger reaction. Cyclization was achieved after 8 h of reaction. After the reaction was completed, the charged groups were removed by washing with saturated NaHCO3, and the product was precipitated and dried in n-hexane at 60 °C to remove triphenylphosphine, thus obtaining the cyclic polymer with a dithioester structure.

[0164] The above cyclic polymer was placed in a test tube, and 0.05 mmol of azobisisobutyronitrile (AIB), 10 mmol of styrene (St), and 2 mL of dioxane were added. After stirring until homogeneous, the mixture was subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was then carried out at 80 °C for 8 hours. After the reaction was completed, the reaction was terminated by cooling, yielding the fourth reaction product. The fourth reaction product was precipitated in n-hexane, washed three times, and dried to obtain the cyclic-chain hybrid polymer.

[0165] The chain transfer reagent CPADB used has the following structural formula:

[0166]

[0167] Example 4

[0168] In a 50 mL test tube, 0.2 mmol of 3-trimethylsilylpropynyl methacrylate (NMA), 0.02 mmol of azobisisobutyronitrile, 0.1 mmol of chain transfer reagent CPADB, 10 mmol of tert-butyl 4-vinylphenylcarbamate (AStBoc), and 2 mL of dioxane were added. The mixture was stirred thoroughly and then subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling, yielding the first reaction product. The first reaction product was precipitated in n-hexane, washed three times, and dried to obtain a pink linear polymer PNMA-b-PAStBoc with a dithioester structure.

[0169] The linear polymer PNMA-b-PAStBoc with a dithioester structure was placed in a test tube, and 0.02 mmol of azobisisobutyronitrile, 0.2 mmol of 4-chloromethylstyrene, and 2 mL of dioxane were added. After stirring until homogeneous, the mixture was subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling to obtain the second reaction product. The second reaction product was precipitated in n-hexane, washed three times, and dried to obtain the pink linear polymer PNMA-b-PAStBoc-b-PVBC with a dithioester structure.

[0170] The pink linear polymer PNMA-b-PAStBoc-b-PVBC with a dithioester structure was placed in a test tube, and 0.2 mmol of NaN3 and 5 mmol of trifluoroacetic acid were added. The reaction was carried out for 24 h to obtain the third reaction product. The third reaction product was precipitated in n-hexane, washed three times, and dried to obtain the linear polymer PNMA-b-PStNH2-b-PVBC with a dithioester structure and charged azide groups at the end.

[0171] The linear polymer PNMA-b-PStNH2-b-PVBC, which has a dithioester structure and is terminally azide and charged, was placed in a test tube. 1 mL of dimethylformamide was added to dissolve it, followed by the addition of 0.2 mmol of cuprous bromide catalyst. A click reaction was initiated at room temperature, and cyclization was achieved after 24 h. After the reaction, the charged groups were removed by washing with saturated NaHCO3, and copper ions were removed by dialysis with deionized water, thus preparing the cyclic polymer with the dithioester structure.

[0172] The above cyclic polymer was placed in a test tube, and 0.05 mmol of azobisisobutyronitrile (AIB), 10 mmol of styrene (St), and 2 mL of dioxane were added. After stirring until homogeneous, the mixture was subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling, yielding the fourth reaction product. The fourth reaction product was precipitated in n-hexane, washed three times, and dried to obtain the cyclic-chain hybrid polymer.

[0173] Example 5

[0174] In a 50 mL test tube, 0.2 mmol of hydroxyethyl methacrylate (HEMA), 0.02 mg of azobisisobutyronitrile (AIB), 0.1 mL of chain transfer reagent CPADB, 10 mmol of methacrylic acid (AA), and 2 mL of dioxane were added and stirred until homogeneous. The mixture was then subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling, yielding the first reaction product. The first reaction product was precipitated in n-hexane, washed three times, and dried to obtain a pink linear polymer of PHEMA-b-PAA with a dithioester structure.

[0175] The pink linear polymer PHEMA-b-PAA with a dithioester structure was placed in a test tube, and 0.02 mmol of azobisisobutyronitrile, 0.1 mmol of 4-chloromethylstyrene, and 2 mL of dioxane were added. After stirring, the mixture was subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling, yielding the second reaction product. The second reaction product was precipitated in n-hexane, washed three times, and dried to obtain the pink linear polymer PHEMA-b-PAA-b-PVBC with a dithioester structure.

[0176] The pink linear polymer PHEMA-b-PAA-b-PVBC with a dithioester structure was placed in a test tube and dissolved in 1 mL of dimethylformamide. Then, 5 mmol of methylimidazole was added to introduce charge, followed by the addition of 1% triphenylphosphine palladium catalyst and 1% cesium carbonate catalyst. The linear polymer was subjected to a coupling reaction at 80°C for 24 hours to achieve cyclization. After the coupling reaction, the cyclic polymer was precipitated using n-hexane at 60°C, which also removed the charged groups. The cesium carbonate was then removed by washing with water, and the polymer was dried to obtain the cyclic polymer with a dithioester structure.

[0177] The above cyclic polymer was placed in a test tube, and 0.05 mmol of azobisisobutyronitrile (AIB), 10 mmol of styrene (St), and 2 mL of dioxane were added. After stirring until homogeneous, the mixture was subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling, yielding the third reaction product. The third reaction product was precipitated in n-hexane, washed three times, and dried to obtain the cyclic-chain hybrid polymer.

[0178] Example 6

[0179] 1 mmol of methyl methacrylate (MMA), 0.02 mg of azobisisobutyronitrile (AIB), 0.1 mL of chain transfer reagent CPADB, 10 mmol of 2-vinylpyridine (2VP), and 2 mL of dioxane were added to a 50 mL test tube. The mixture was stirred thoroughly and then subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling, yielding the first reaction product. The first reaction product was precipitated in n-hexane, washed three times, and dried to obtain a pink linear polymer PMMA-b-P2VP with a dithioester structure.

[0180] The pink linear polymer PMMA-b-P2VP with a dithioester structure was placed in a test tube, and 0.02 mmol of azobisisobutyronitrile, 0.2 mmol of 4-chloromethylstyrene, and 2 mL of dioxane were added. After stirring until homogeneous, the mixture was subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling to obtain the second reaction product. The second reaction product was precipitated in n-hexane, washed three times, and dried to obtain the pink linear polymer PMMA-b-P2VP-b-PVBC with a dithioester structure.

[0181] The pink linear polymer PMMA-b-P2VP-b-PVBC with a dithioester structure was placed in a test tube, and 0.2 mmol of NaN3, 10 mmol of iodoethane, and 1 mL of dimethylformamide were added. The reaction was allowed to proceed for 24 h to obtain the third reaction product. The third reaction product was precipitated in n-hexane, washed three times, and dried to obtain PMMA-b-P2VP-b-PVBC with a dithioester structure and charged terminal azide groups.

[0182] The above-mentioned PMMA-b-P2VP-b-PVBC with a dithioester structure and charged terminal azide groups was placed in a test tube, dissolved in 1 mL of dimethylformamide, and then 0.2 mmol of triphenylphosphine catalyst was added. After stirring for 30 min, another 0.6 mmol of triphenylphosphine catalyst was added and the mixture was heated to 40 °C to carry out the Staudinger reaction. Cyclization was achieved after 8 h of reaction. After the reaction was completed, the charged groups were removed by washing with saturated NaHCO3, and the product was precipitated and dried in n-hexane at 60 °C to remove triphenylphosphine, thus obtaining the cyclic polymer with the dithioester structure.

[0183] The above cyclic polymer was placed in a test tube, and 0.05 mmol of azobisisobutyronitrile (AIB), 10 mmol of styrene (St), and 2 mL of dioxane were added. After stirring until homogeneous, the mixture was subjected to a freeze-evacuation-thawing cycle three times to remove oxygen. The polymerization reaction was carried out at 80 °C for 8 h. After the reaction was completed, the reaction was terminated by cooling, yielding the fourth reaction product. The fourth reaction product was precipitated in n-hexane, washed three times, and dried to obtain the cyclic-chain hybrid polymer.

[0184] Characterization

[0185] 1. GPC Testing

[0186] Gel permeation chromatography (GPC) was performed on Example 3, and the results are as follows: Figure 1 As shown. Figure 1 This image shows a comparison of gel permeation chromatography (GPC) curves of the linear polymer precursor (linear), cyclic polymer (cyclized), and ring-chain hybrid polymer (jointed) of Example 3 of the present invention. Figure 1As can be seen, the GPC curve shifted slightly to the right after cyclization, which is consistent with the characteristics of cyclic polymers. Subsequently, after chain grafting, the GPC curve shifted significantly to the left, which is consistent with the characteristics of cyclic-chain hybrid polymers.

[0187] 2. DLS Test

[0188] Dynamic light scattering (DLS) tests were performed on Example 3, and the results are as follows: Figure 2 As shown. Figure 2 This diagram shows a comparison of dynamic light scattering (DLS) data for linear polymer precursors (linear), cyclic polymers (cyclized), and ring-chain hybrid polymers (jointed) according to Example 3 of the present invention. Figure 2 It can be seen that the average particle size of the cyclic polymer is smaller than that of the linear polymer precursor. After forming the cyclic-chain hybrid polymer, the average particle size is larger than that of the linear polymer precursor, further demonstrating that the method of the present invention prepares the cyclic-chain hybrid polymer.

[0189] 3. TEM test

[0190] Images of the ring-chain hybrid polymer samples were observed using transmission electron microscopy. The ring-chain hybrid polymers were visualized by grafting PEO-CHO with Mn = 1000. Figure 3 The image shown is a sample of a ring-chain hybrid polymer observed under a transmission electron microscope according to Example 3 of the present invention. Figure 3 It can be seen that the method of the present invention has prepared a ring-chain hybrid polymer.

[0191] Industrial availability

[0192] Cyclic polymers, as a type of high-molecular colloidal nanoparticle with a special structure, can achieve functional coupling between ring-chain hybrid polymers. For example, leveraging the non-entanglement and organ-transfer capabilities of cyclic polymers, the polymer chains can be used as drug carriers to simultaneously achieve drug loading and delivery. Targeting groups can also be introduced onto the chains, giving the entire structure targeted recognition capabilities, which has application value in cancer cell targeting and lesion clearance. Furthermore, loading fluorescent groups can enable bioimaging, showing potential applications in disease diagnosis and treatment, drug tracking, and blood circulation monitoring.

[0193] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0194] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for producing a ring-chain hybrid structure polymer, characterized by, The method comprises the following steps: obtaining a linear polymer precursor having a group A, a group B and a side group F, and making the linear polymer precursor have a thioester bond structure; binding a compound D to at least part of the side groups F of the linear polymer precursor, and converting at least part of the side groups of the linear polymer precursor into a charged group; making the group A and the group B undergo a ring closure reaction to form a cyclic polymer having a thioester bond structure and a charged group; optionally removing the charged group to obtain a cyclic polymer; making the cyclic polymer undergo a polymerization reaction by using the thioester bond structure to obtain a ring-chain hybrid structure polymer; the group A is selected from one or more than two combinations of azido, halogen, substituted or unsubstituted alkenyl or mercapto; the group B is selected from one or more than two combinations of substituted or unsubstituted alkynyl, ester, halogen, hydroxyl, substituted or unsubstituted amino, substituted or unsubstituted amide, substituted or unsubstituted alkenyl or mercapto; the side group F is selected from one or more than two combinations of carboxyl, amino, halogen, tertiary amine, pyridyl, imidazolyl; the compound D comprises one or more than two combinations selected from carboxylic acid compounds, amino compounds, halogenated compounds, tertiary amine compounds, pyridine compounds, imidazole compounds.

2. The production method according to claim 1, characterized by, The number average molecular weight of the linear polymer precursor is 5000 g / mol-200000 g / mol.

3. The preparation method according to claim 2, characterized in that, The number average molecular weight of the linear polymer precursor is 10000 g / mol-100000 g / mol.

4. The production method according to any one of claims 1 to 3, characterized by, The compound D and the linear polymer precursor convert at least part of the side groups F of the linear polymer precursor into a charged group through a quaternization reaction or a salt formation reaction.

5. The method of any one of claims 1-3, wherein, The linear polymer precursor has a thioester bond structure by using a chain transfer reagent.

6. The production method according to claim 5, wherein The chain transfer reagent comprises a bis-thioester derivative or a tris-thioester derivative.

7. The production method according to claim 6, wherein The bis-thioester derivative or the tris-thioester derivative has one or more than two combinations of hydroxyl, amino, halogen, ester, carboxyl.

8. The method of any one of claims 1-3, wherein, The ring closure reaction comprises one or more than two combinations of a click reaction, a Staudinger reaction, a coupling reaction.

9. The method of any one of claims 1-3, wherein, In the preparation system, the concentration of the linear polymer precursor is 0.1-300 mg / mL.

10. The method of claim 9, wherein, In the preparation system, the concentration of the linear polymer precursor is 10-100 mg / mL.

11. The method of any one of claims 1-3, wherein, The temperature of the ring closure reaction is -80-100 ℃, and the time of the ring closure reaction is 1-48 hours.

12. The method of claim 11, wherein, The temperature of the ring closure reaction is 25-80 ℃, and the time of the ring closure reaction is 3-36 hours.

13. The method of any one of claims 1-3, wherein, The ring closure reaction is carried out in a solvent.

14. The method of claim 13, wherein, The dielectric constant of the solvent is 2.2-49.

15. The method of claim 14, wherein, The dielectric constant of the solvent is 2.6-37.

16. A ring-chain hybrid structure polymer, characterized by, Prepared by the method for preparing a ring-chain hybrid structure polymer according to any one of claims 1-15.

17. The ring-chain hybrid structure polymer according to claim 16, wherein The diameter of the ring in the ring-chain hybrid structure polymer is 3-100 nm.

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