Preparation method of ring-chain hybrid structure polymer and ring-chain hybrid structure polymer

Abstract

The invention 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 which has a group A, a group B and a side group F and has a thioester bond structure; combining a compound D with at least part of the pendant group F of the linear polymer precursor to convert at least part of the pendant group of the linear polymer precursor into a charged group; carrying out ring-closure reaction on the group A and the group B to form a charged cyclic polymer with a thioester bond structure; optionally removing the charged groups to obtain a cyclic polymer; and carrying out polymerization reaction on the cyclic polymer by utilizing a thioester bond structure to obtain the polymer with the ring-chain hybrid structure. The preparation method disclosed by the invention is simple in reaction process, high in solid content, few in byproducts and low in cost in the product treatment and separation process, and has a huge application value in the aspect of industrial production.

Description

Technical Field

[0001] The invention relates to a preparation method of a ring-chain hybrid structure polymer and the ring-chain hybrid structure polymer, belonging to the field of polymer materials. Background Art

[0002] In recent years, the hybridization of colloids and polymers has received extensive attention from the scientific community. Colloids, as particles of 1-100 nm, have excellent effects in acoustics, light, electricity, magnetism, heat, catalysis and other functions, but their ability to assemble into superstructures and functional coupling is insufficient. Polymer chains have rich chain composition and topological structure, assembled superstructure and responsiveness. Composites with colloids can complement each other's advantages and produce more new materials. At present, there have been studies and reports on colloid-polymer hybrid structures and their properties.

[0003] In 2015, cited reference 1 reported a ball-chain hybrid structure constructed by oligosiloxane (POSS) molecular nanoparticles, which can achieve selective assembly to form a highly ordered supramolecular lattice. It also has a rich phase structure and sub-10nm fine lines. This structural unit is described as a "giant atom" and is expected to become a new type of material building unit.

[0004] However, due to the difficulty in preparing cyclic polymers, their topological structures have not been widely studied. Using cyclic polymers as colloidal structural units and combining them with polymer chains has become a challenging problem in the field. The preparation of ring-chain hybrid structures can enable in-depth research on their physical and chemical properties, and compare their properties with other reported colloid-polymer chain hybrid structures, which has great scientific significance.

[0005] Therefore, studying a method for preparing a ring-chain hybrid structure polymer has become a technical problem that needs to be solved urgently.

[0006] Reference 1: Stephen ZD Cheng Macromolecules 2015, 48, 19, 7172-7179. Summary of the invention

[0007] Problem that 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 structure polymer. The method has a simple reaction process, high solid content, few by-products, low cost in the process of processing and separating products, and has great application value in industrial production.

[0009] Solutions for solving problems

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

[0011] Obtaining a linear polymer precursor, wherein the linear polymer precursor has a group A, a group B, and a side group F, and making the linear polymer precursor have a thioester bond structure;

[0012] combining compound D with at least part of the side groups F of the linear polymer precursor to convert at least part of the side groups of the linear polymer precursor into charged groups;

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

[0014] optionally removing the charged group to obtain a cyclic polymer;

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

[0016] [2] The preparation method according to [1] above, wherein the group A is selected from one or a combination of two or more of an azide group, a halogen group, a substituted or unsubstituted alkenyl group or a thiol group; and / or

[0017] The group B is selected from one or a combination of two or more of a substituted or unsubstituted alkynyl group, an ester group, a halogen group, a hydroxyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted amide group, a substituted or unsubstituted alkenyl group or a thiol group; and / or

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

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

[0020] [4] The preparation method according to any one of [1] to [3] above, wherein the compound D comprises one or a combination of two or more 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 through a quaternization reaction or a salt-forming reaction to convert at least part of the side groups F of the linear polymer precursor into charged groups.

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

[0023] [6] The preparation method according to any one of [1] to [5] above, wherein the ring-closing reaction comprises one or a combination of two or more of a click reaction, a Staudinger reaction, and a coupling reaction.

[0024] [7] The preparation method according to any one of [1] to [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] to [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] to [8] above, wherein the ring-closing reaction is carried out in a solvent; preferably, the dielectric constant of the solvent is 2.2-49, preferably 2.6-37.

[0027]

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

[0028] Effects of the Invention

[0029] The preparation method of the ring-chain hybrid structure polymer of the present invention has simple reaction process, high solid content, few by-products, low cost of processing and separating products, and has great application value in industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A comparison chart of gel permeation chromatography (GPC) curves of the linear polymer precursor (linear), cyclic polymer (cyclization) and ring-chain hybrid structure polymer (chain-joining) of Example 3 of the present invention is shown.

[0031] Figure 2A comparison chart of dynamic light scattering (DLS) data of the linear polymer precursor (linear), cyclic polymer (cyclization) and ring-chain hybrid structure polymer (chain-joining) of Example 3 of the present invention is shown.

[0032] Figure 3 The sample picture of the ring-chain hybrid structure polymer observed under a transmission electron microscope according to Example 3 of the present invention is shown, wherein the ring-chain hybrid structure polymer is visualized by grafting PEO-CHO with Mn=1000. DETAILED DESCRIPTION

[0033] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The word "exemplary" used here means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments.

[0034] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In other examples, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

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

[0036] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0037] In the present specification, a numerical range expressed using "above" or "below" means a numerical range including the number.

[0038] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0039] In this specification, the word "optionally" is used to indicate that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0040] In this specification, the unit names used are all international standard unit names, and unless otherwise stated, the "%" used indicates weight or mass percentage.

[0041] In this specification, "(meth)acrylic acid" means including both acrylic acid and methacrylic acid. In addition, in this specification, "(meth)" has the same meaning in all cases.

[0042] In the present specification, "halogen" means a "chlorine atom", a "bromine atom" or an "iodine atom".

[0043] In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0044] The present invention provides a preparation method of a ring-chain hybrid structure polymer, wherein the preparation method uses a linear polymer precursor as a starting material for preparation. The preparation method of the ring-chain hybrid structure polymer of the present invention has a simple reaction process, high solid content, few by-products, low cost in the process of processing and separating products, and has great application value in industrial production.

[0045] <Linear polymer precursor>

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

[0047] Specifically, in the present invention, the polymer monomer may be one or a combination of two or more of (meth)acrylic monomers, (meth)acrylamide monomers, styrene monomers and vinyl monomers.

[0048] The (meth)acrylic monomer may include (meth)acrylic acid or (meth)acrylic acid alkyl ester. As for the (meth)acrylic acid alkyl ester, there may be exemplified a linear or branched (meth)acrylic acid alkyl ester having an alkyl group with 1 to 10 carbon atoms. For example, as the alkyl group, there may be exemplified a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a cyclohexyl group, a heptyl group, a 2-ethylhexyl group, and the like.

[0049] The (meth)acrylamide monomers may include one or a combination of two or more of (meth)acrylamide, N-methylacrylamide, N,N-dimethylacrylamide, N-hydroxyethylacrylamide, N-hydroxymethylacrylamide, etc.

[0050] For styrene monomers, they may include styrene, substituted styrene, etc. For substituted styrene, the substituent may include alkyl, alkenyl, alkoxy, etc., the carbon number of the alkyl, alkenyl, alkoxy is preferably 1-5, and the alkyl, alkenyl, alkoxy may further include a substituent.

[0051] As for the vinyl monomer, it may include ethylene, propylene, isopropylene, butylene, isobutylene, pentene, isopentene, butadiene and the like.

[0052] In some specific embodiments, the linear polymer precursor of the present invention can 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 is the same as or different from the group B, and the group A, the group B and the side group F are different.

[0053] Side group F

[0054] The side group F may be selected from one or a combination of two or more of a carboxyl group, an amino group, a halogen group, a tertiary amine group, a pyridyl group, and an imidazole group.

[0055] The present invention does not specifically limit the type of monomer containing the side group F, as long as it can be copolymerized and has the above side group F. The present invention does not specifically limit the position of the side group F in the monomer, and it can replace any feasible hydrogen in the monomer.

[0056] Specifically, in the present invention, the monomer containing a side group F can be one or a combination of two or more of a (meth)acrylic monomer containing a side group F, a (meth)acrylamide monomer containing a side group F, a styrene monomer containing a side group F, and a vinyl monomer containing a side group F.

[0057] In some specific embodiments, the (meth)acrylic monomer whose side group F is a carboxyl group may be (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, and the like.

[0058] In some specific embodiments, the styrenic monomer whose side group F is a halogen can be a halogen-substituted C 1-5 Alkyl-substituted styrenes, halogen-substituted C 1-5 Alkenyl substituted styrenes, for example: 4-chloromethylstyrene (VBC), 4-chloroethylstyrene, 4-bromomethylstyrene, 4-bromoethylstyrene, etc. The styrene monomer whose side group F is an amino group can be an amino substituted styrene monomer, and preferably the amino group can be protected by a protecting group, specifically by a tert-butyloxycarbonyl group, for example tert-butyl 4-vinylphenylcarbamate (AStBoc).

[0059] In some specific embodiments, the vinyl monomer whose side group F is a pyridyl group may be 2-vinylpyridine or the like.

[0060] In some specific embodiments, the vinyl monomer whose side group F is an imidazole group may be 2-vinylimidazole or the like.

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

[0062] Group A

[0063] The group A of the present invention may refer to the terminal group A of the linear polymer precursor. The group A may be one or a combination of two or more selected from an azide group, a halogen group, a substituted or unsubstituted alkenyl group or a thiol group. The group A of the present invention may be introduced by directly using a monomer containing the group A, for example, the group A may be introduced by a monomer containing a halogen group; the group A of the present invention may also be introduced by a substitution reaction after obtaining a linear polymer, for example, an azide group or a thiol group is introduced after obtaining a linear polymer; of course, the present invention may also be to first introduce the group A into the monomer by a substitution reaction, and then to perform a polymerization reaction.

[0064] In the present invention, the monomer containing group A can be one or a combination of two or more of a (meth) acrylic monomer containing group A, a (meth) acrylamide monomer containing group A, a styrene monomer containing group A, and a vinyl monomer containing group A. The monomer containing group A of the present invention has the same selectable range as the monomer containing side group F, but the monomer containing group A of the present invention is different from the monomer containing side group F. For example, when group A is halogen, side group F is not halogen.

[0065] In some specific embodiments, when group A is an azido group, it can be obtained by subjecting a polymer unit to a substitution reaction with an azide salt, thereby firstly making the polymer unit have an azido group. Preferably, the polymer unit has a halogen, and the halogen is replaced with an azido group by using an azide salt. In some specific embodiments, when group A is an azido group, it can first obtain a linear polymer, and then subject the linear polymer to a substitution reaction with an azide salt to obtain the linear polymer precursor, thereby firstly making the linear polymer precursor have an azido group.

[0066] In some specific embodiments, when group A is a thiol group, a thiol reagent can be used to react with a polymer unit to obtain a thiol group, so that the polymer unit first has a thiol group. In some specific embodiments, when group A is a thiol group, a linear polymer can be obtained first, and then the linear polymer can be reacted with a thiol reagent to obtain a linear polymer precursor, so that the linear polymer precursor first has a thiol group. In addition, in the presence of a thiol reagent, the linear polymer precursor can also directly undergo a ring-closing reaction.

[0067] In some specific embodiments, the styrene monomer in which group A is halogen can be halogen-substituted C 1-5 Alkyl-substituted styrenes, halogen-substituted C 1-5 Alkenyl-substituted styrenes, for example, 4-chloromethylstyrene (VBC), 4-chloroethylstyrene, 4-bromomethylstyrene, 4-bromoethylstyrene, and the like.

[0068] In some specific embodiments, for the styrene monomer in which group A is an alkenyl group, it can be 4-(3-butylene)styrene, 4-vinylstyrene, 4-acrylstyrene, and the like.

[0069] Group B

[0070] The group B of the present invention may refer to the end group B of a linear polymer precursor. In the present invention, the group A and the group B may be the same or different. For the group B, it may be selected from one or more combinations of substituted or unsubstituted alkynyl, ester group, halogen, hydroxyl, substituted or unsubstituted amino, substituted or unsubstituted amide group, substituted or unsubstituted alkenyl. Wherein the carbon number of the alkynyl group may be 1-5. For substituents, the substituents may include alkyl, alkenyl, alkoxy, etc., and the carbon numbers of the alkyl, alkenyl, and alkoxy groups are preferably 1-5, and the alkyl, alkenyl, and alkoxy groups may further include substituents.

[0071] In some specific embodiments, the styrene monomer in which group B is halogen may be halogen-substituted C 1-5 Alkyl-substituted styrenes, halogen-substituted C 1-5 Alkenyl-substituted styrenes, for example, 4-chloromethylstyrene (VBC), 4-chloroethylstyrene, 4-bromomethylstyrene, 4-bromoethylstyrene, and the like.

[0072] In some specific embodiments, since the (meth)acrylic acid alkyl ester monomer contains an ester group, the monomer having a group B may be a (meth)acrylic acid alkyl ester monomer. Examples include linear or branched (meth)acrylic acid alkyl esters having an alkyl group with 1 to 10 carbon atoms. For example, examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, and the like.

[0073] In some specific embodiments, group B is an alkynyl (meth)acrylate monomer, in which at least one H in the above alkyl (meth)acrylate monomer is substituted 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 in an alkyl (meth)acrylate monomer, in which at least one H in the above alkyl (meth)acrylate monomer is substituted by an amino group, for example: 2-aminoethyl methacrylate or a salt thereof, for example, 2-aminoethyl methacrylate hydrochloride (AMA).

[0075] In some specific embodiments, group B is a (meth)acrylic acid alkyl ester monomer having a hydroxyl group, which may be a (meth)acrylic acid alkyl ester monomer in which at least one H is substituted by 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 may be a (meth)acrylamide monomer. Specifically, it may include one or a combination of two or more of (meth)acrylamide, N-methylacrylamide, N,N-dimethylacrylamide, N-hydroxyethylacrylamide, N-hydroxymethylacrylamide, etc.

[0077] In some specific embodiments, when group B is a thiol group, a thiol reagent can be used to react with a polymer unit to obtain a thiol group, so that the polymer unit first has a thiol group. In some specific embodiments, when group B is a thiol group, a linear polymer can be obtained first, and then the linear polymer can be reacted with a thiol reagent to obtain a thiol group, so that the linear polymer precursor first has a thiol group.

[0078] In some specific embodiments, for the styrene monomer in which the group B is an alkenyl group, it can be 4-(3-butylene)styrene, 4-vinylstyrene, 4-acrylstyrene, and the like.

[0079] Polymerization

[0080] The polymerization reaction of the present invention can be obtained by solution polymerization, and the polymerization modes include random copolymerization, alternating copolymerization, block copolymerization and the like.

[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 the monomer having a side group F and a monomer having a group A are firstly polymerized and then polymerized with a monomer having a group B; or the monomer having a side group F and a monomer having a group B are firstly polymerized and then polymerized with a monomer having a group A; or the linear polymer is obtained by polymerizing at least one polymer monomer without a side group F, a group A and a group B, and then introducing the 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 the polymer monomer in a solvent in the presence of a chain transfer agent and an initiator to obtain a linear polymer precursor, such as free radical polymerization, etc. By using a chain transfer agent, the linear polymer precursor can have a thioester bond structure.

[0083] For the chain transfer agent, i.e., the reversible addition-fragmentation chain transfer radical polymerization (RAFT) agent, it may include a dithioester derivative or a trithioester derivative. Specifically, the dithioester derivative or the trithioester derivative has one or a combination of two or more of a hydroxyl group, an amino group, a halogen group, an ester group, and a carboxyl group. Specifically, the chain transfer agent may be OH-RAFT, CPADB or D-CPADB, and the specific structural formula is as follows:

[0084]

[0085] The initiator may be one or a combination of two or more selected from organic peroxides and azo compounds. The organic peroxide is preferably dibenzoyl peroxide, diisopropyl peroxide, di-tert-butyl peroxide, tert-butyl benzoyl oxide, methyl ethyl ketone peroxide, dodecyl peroxide, tert-butyl perbenzoate, diisopropyl peroxydicarbonate, etc.; the azo compound is preferably azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleronitrile, azobiscyclohexylcarbonitrile, dimethyl azobisisobutyrate, etc.

[0086] The present invention does not specifically limit the solvent, and it can be an organic solvent or water commonly used in the art, preferably an organic solvent. Examples thereof 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 conditions for the polymerization reaction are not particularly limited in the present invention and can be selected as needed, as long as the desired linear polymer precursor can be obtained. Generally speaking, the polymerization reaction time can be 1 to 24 hours at a temperature of 50 to 100°C to obtain a polymerization product. The polymerization product is then separated to obtain a linear polymer precursor. The present invention does not particularly limit the separation method, which can be a commonly used separation method in the art, such as using n-hexane to precipitate the linear polymer precursor and using a centrifuge for separation. Preferably, the polymerization reaction is carried out in an anaerobic environment, and generally a freeze-pump-thaw cycle of 3 to 5 times can be used for deoxygenation.

[0088] In other specific embodiments, the present invention may also be to use a chain transfer agent to terminate the reaction after the linear polymer is prepared, so that the linear polymer precursor has a thioester bond structure. Specifically, in the presence of an initiator system, cationic polymerization of the polymer monomer occurs in a solvent to obtain a linear polymer precursor.

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

[0090] As for the initiator, it can be tertiary halogenated hydrocarbon, benzyl halogenated hydrocarbon, ether compound, alcohol compound, ester compound, etc. Specifically, the initiator includes one or a combination of two or more of 1-(4-methoxyphenyl)ethanol, tert-butyl carbinol, methyl phenyl carbinol, benzhydrol, isopropyl carbinol, etc.

[0091] For the activator, the activator may specifically include a Lewis acid. The Lewis acid may generally be one or more combinations of metal halides, organometallic halides or their complexes. Specifically, in the present invention, the Lewis acid includes but is not limited to: one or more combinations of boron trifluoride, aluminum trichloride, zinc dichloride, titanium tetrachloride, tin tetrachloride, antimony trichloride, chromium tetrachloride, iron trichloride, gallium trichloride, titanium tetrachloride, alkylaluminum chloride, etc. Lewis acid is preferably one or more combinations of tin tetrachloride, boron trifluoride, gallium trichloride, etc.

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

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

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

[0095] The conditions for cationic polymerization are not particularly limited in the present invention and can be selected as needed, as long as the required linear polymer precursor can be obtained. Generally speaking, the polymerization reaction time can be 0.5 hours to 12 hours at a temperature of -90 to 50°C to obtain a polymerization reaction product. Then, the polymerization reaction product is separated to obtain a linear polymer precursor. The present invention does not particularly limit the method of separation and treatment, which can be a commonly used separation method in the art, such as using n-hexane to precipitate the linear polymer precursor and using a centrifuge for separation. Further, the linear polymer precursor is terminated by using a chain transfer agent, and the linear polymer precursor has a thioester bond structure. The chain transfer agent is the same as the above-mentioned chain transfer agent, and can be OH-RAFT, CPADB or D-CPADB, etc. In addition, the present invention does not particularly limit the amount of linear polymer precursor used, and generally requires excessive use.

[0096] Then, the linear polymer precursor having a thioester bond structure is subjected to separation treatment to obtain a linear polymer precursor. The present invention does not particularly limit the separation treatment method, and it can be a separation method commonly used in the art, such as using n-hexane to precipitate the linear polymer precursor and using a centrifuge to separate, thereby obtaining a linear polymer precursor having a thioester bond structure.

[0097] In some specific embodiments, the number average molecular weight of the linear polymer precursor may be 5000-200000 g / mol, preferably 10000-100000 g / mol.

[0098] <Method for preparing ring-chain hybrid structure polymer>

[0099] The preparation method of the ring-chain hybrid structure polymer of the present invention is carried out using a linear polymer precursor having a side group F, a group A and a group B as a starting material, and may include the following steps:

[0100] combining compound D with at least part of the side groups F of the linear polymer precursor to convert at least part of the side groups F of the linear polymer precursor into charged groups;

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

[0102] optionally removing the charged group to obtain a cyclic polymer;

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

[0104] Imparting Charge to Linear Polymer Precursors

[0105] Compound D is combined with at least part of the side groups F of the linear polymer precursor to convert at least part of the side groups F of the linear polymer precursor into charged groups. The side groups F of the linear polymer precursor of the present invention are converted into charged groups, so that the polymer chain is charged. In this process, the polymer chain is modified to be charged, so that repulsion is generated between the polymer chains, and the magnitude of the interchain repulsion force generated by different charge amounts is different. This repulsion effectively reduces the side reactions between the molecular chains during the cyclization process, creates conditions for the subsequent intramolecular reaction of the group A and the group B, thereby achieving product preparation at high concentrations.

[0106] In some specific embodiments, the compound D and the linear polymer precursor are reacted by quaternization reaction or salt formation reaction to convert at least part of the side groups F of the linear polymer precursor into charged groups. Taking the salt formation reaction (acid-base reaction) as an example, the side groups F of the linear polymer precursor are acidic or basic groups, and the compound D is a base or an acid accordingly (i.e., the reactive group of the compound D that can react with the side groups F is a basic or acidic group).

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

[0108] Compound D can be any compound as long as it has a group that can react with the side group F to convert it into a charged group. Exemplarily, the compound D includes one or a combination of two or more selected from carboxylic acid compounds, amino compounds, halogenated compounds, tertiary amine compounds, pyridine compounds, and imidazole compounds. Specifically, compound D can be trifluoroacetic acid, iodoethane, methylimidazole, pyridine, etc.

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

[0110] Here, of 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 the compound D.

[0111] Furthermore, a portion of the side groups F of the linear polymer precursor may be converted into charged groups, while the other portion remains in the form of side groups F; or all of the side groups F may be converted into charged groups. In some specific embodiments, after the reaction of charging the linear polymer precursor is completed, the proportion of the side groups F converted into charged groups is 10% to 100% by mole, preferably 60% to 100% by mole.

[0112] In some specific embodiments, the linear polymer precursor is charged in a solvent. Specifically, the linear polymer precursor is dissolved in a solvent, and then compound D is added, and optionally stirred to react. The stirring time is not particularly limited in the present invention, and can generally be 10-60 minutes.

[0113] The present invention does not specifically limit the solvent, and it can be an organic solvent or water commonly used 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. For example, organic solvents include ketones such as acetone, methyl ethyl ketone, dimethyl acetone, methyl isobutyl ketone, acetophenone, N-methyl-2-pyrrolidone, ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbons such as benzene, toluene, xylene, chlorobenzene, amides such as N,N-dimethylformamide and N,N-dimethylacetamide, etc.

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

[0115] In addition, it should be noted that when preparing a linear polymer precursor, when the linear polymer precursor needs to introduce an azide group or a thiol group, it can be carried out simultaneously with the linear polymer precursor being charged, or the azide group or the thiol group can be introduced first and then the linear polymer precursor is charged. Further, in order to improve the reaction efficiency, it is preferred that the introduction of the azide group and the charging of the linear polymer precursor are carried out simultaneously. In order to improve the reaction efficiency, the linear polymer precursor can be charged first, and then the thiol group can be introduced and the ring-closing reaction can be carried out simultaneously.

[0116] Closed-loop reaction

[0117] The group A and the group B undergo a ring-closing reaction to form a charged cyclic polymer having a thioester bond structure. The group A and the group B are a group combination that can react with each other to form a covalent bond, and the two 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, thiol / alkenyl, thiol / thiol, alkenyl / thiol, alkenyl / alkenyl, etc.

[0119] In the group combination described herein, one of the two groups separated by the symbol “ / ” is group A and the other is group B, and the order of appearance is not limited.

[0120] The conditions for the ring-closing reaction are not particularly limited in the present invention, as long as the reaction is carried out under conditions that allow 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, but it can also be carried out without a catalyst.

[0121] In some specific embodiments, the ring-closing reaction may include one or a combination of two or more of a click reaction, a Staudinger reaction, and a coupling reaction.

[0122] In a specific embodiment, group A / group B is halogen / halogen. In this case, step (3) can be carried out in the presence of a catalyst, and a charged cyclic polymer having a thioester bond structure can be prepared through a coupling reaction.

[0123] In a specific embodiment, group A / group B is an azide / alkyne group. In this case, step (3) can be carried out in the presence of a catalyst, and a cyclic polymer having a thioester bond structure and being charged can be prepared by a click reaction.

[0124] In a specific embodiment, group A / group B is an azide / ester group. In this case, step (3) can be carried out in the presence of a catalyst, and a charged cyclic polymer having a thioester bond structure can be prepared by a Staudinger reaction.

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

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

[0127] In a specific embodiment, group A / group B is alkenyl / alkenyl, which can be prepared by a thiol reagent through a click reaction to obtain a charged cyclic polymer having a thioester bond structure. The present invention does not specifically limit the thiol reagent, for example, commonly used thiol reagents such as 1,2-dimercaptoethane.

[0128] The present invention does not specifically limit the catalyst, and the required catalyst can be selected according to the specific reaction. Among them, the catalyst for the coupling reaction can be triphenylphosphine palladium and carbonate, such as triphenylphosphine palladium and cesium carbonate, etc.; the catalyst for the Staudinger reaction can be triphenylphosphine; the catalyst for the click reaction can be cuprous halide, such as cuprous bromide, etc. Of course, the click reaction can also be performed without a catalyst.

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

[0130] In some specific embodiments, the temperature of the above-mentioned ring-closing reaction is 0 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.

[0131] Removal of the charged groups

[0132] Optionally remove the charged groups to obtain a cyclic polymer. As needed, the present invention can remove the charged groups and use a post-treatment method such as precipitation and washing to obtain a cyclic polymer. Of course, the present invention may not remove the charged groups. Only a post-treatment method such as precipitation and washing is used to obtain a charged cyclic polymer.

[0133] The present invention does not specifically limit the method for removing the charged group. Generally, when an acidic compound D is used, a basic substance is used to remove it. When a basic compound D is used, an acidic substance can be used to remove it.

[0134] For example, when trifluoroacetic acid is used as compound D, saturated NaHCO 3 Washing is done to remove charged groups.

[0135] In addition, the catalyst can be removed by washing with water or during precipitation. For example, triphenylphosphine palladium can be removed by using heated cyclohexane to precipitate the cyclic polymer. When cuprous bromide is used as the catalyst, water dialysis can be used to remove copper ions.

[0136] Preparation of ring-chain hybrid polymers

[0137] Finally, the thioester bond structure is used to carry out a polymerization reaction on the cyclic polymer to obtain a ring-chain hybrid structure polymer.

[0138] The present invention does not elaborate on the polymer monomers, which may be the polymer monomers mentioned above in the present application, for example, one or a combination of two or more of (meth) acrylic monomers, (meth) acrylamide monomers, styrene monomers and vinyl monomers.

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

[0140] Specifically, the polymerization reaction can be carried out in a solvent using a polymer monomer in the presence of an initiator using a thioester bond structure. Specifically, the polymerization reaction is substantially the same as the polymerization reaction for preparing a linear polymer precursor in the present application.

[0141] The present invention does not elaborate on the initiator, solvent, etc., which may be the initiator, solvent, etc. mentioned above in this application.

[0142] <Ring-chain hybrid structure polymer>

[0143] The present invention also provides a ring-chain hybrid structure polymer, which is prepared according to the preparation method of the ring-chain hybrid structure polymer of the present invention, preferably, the diameter of the ring in the ring-chain hybrid structure polymer is 3-100nm. The diameter of the ring in the ring-chain hybrid structure polymer of the present invention can be obtained by transmission electron microscopy (TEM) ranging and dynamic light scattering (DLS) assisted determination.

[0144] Example

[0145] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0146] Example 1

[0147] 0.1 mmol of boron trifluoride ether complex, 0.1 mmol of 1-(4-methoxyphenyl)ethanol (MOPE) and 2 mL of dichloromethane were added to a 50 mL test tube, and the mixture was stirred evenly and subjected to freeze-evacuation-thaw cycles for 3 times to deoxygenate. 1 mmol of 4-(3-butylene)styrene (VSt) was added at 0°C and reacted for 30 min. Then, 10 mmol of 4-chloromethylstyrene (VBC) was added and the reaction was continued for 30 min. After that, 1 mmol of 4-(3-butylene)styrene was added and reacted for 30 min to obtain a first reaction product containing a linear polymer precursor.

[0148] 10 mmol of chain transfer agent OH-RAFT was added to the first reaction product to terminate the reaction and make the first reaction product have a dithioester structure. The first reaction product having a dithioester structure was then precipitated in n-hexane, washed three times and dried to obtain a linear polymer PVSt-b-PVBC-b-PVSt having a dithioester structure.

[0149] The linear polymer PVSt-b-PVBC-b-PVSt with a dithioester structure was placed in a test tube, and 5 mmol 2-methylimidazole was added and stirred for 30 min to make the linear polymer charged. Then 1 mmol 1,2-dimercaptoethane was added and the 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 to remove the charged groups, washed three times, and dried to obtain a cyclic polymer.

[0150] Take the above cyclic polymer in a test tube, add 0.05mmol azobisisobutyronitrile, 10mmol styrene (St) and 2mL dioxane, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h and then carry out polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain the third reaction product. The third reaction product is precipitated in n-hexane, washed three times and dried to obtain a ring-chain hybrid structure polymer.

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

[0152]

[0153] Embodiment 2:

[0154] Add 10mmol methacrylic acid (MAA), 0.02mmol azobisisobutyronitrile, 0.1mmol chain transfer agent D-CPADB, 0.2mmol 4-chloromethylstyrene and 2mL dioxane to a 25mL test tube, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain the first reaction product. The first reaction product is 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] Take the above pink linear polymer PVBC-b-PMAA-b-PVBC with a disulfide structure in a test tube, add 1 mL of dimethylformamide, add 2 mmol of methylimidazole after dissolution, and stir for 30 minutes to charge the linear polymer. Then add 1% triphenylphosphine palladium and 1% cesium carbonate (based on the total mass of the reactants) as catalysts, and make the linear polymer undergo coupling reaction at 80°C for 12 hours to achieve cyclization. After the coupling reaction, use 60°C n-hexane to precipitate the cyclic polymer and remove the charged groups at the same time, wash with water to remove cesium carbonate, and dry to obtain a cyclic polymer with a disulfide structure.

[0156] Take the above cyclic polymer in a test tube, add 0.05mmol azobisisobutyronitrile, 10mmol 2-vinylpyridine (2VP) and 2mL dioxane, stir evenly, freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain the second reaction product. The second reaction product is precipitated in n-hexane, washed three times and dried to obtain a ring-chain hybrid structure polymer.

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

[0158]

[0159] Example 3

[0160] Add 1mmol methyl methacrylate (MMA), 0.02mg azobisisobutyronitrile, 0.1mmol chain transfer agent CPADB, 10mmol tert-butyl 4-vinylphenylcarbamate (AStBoc), and 2mL dioxane into a 50mL test tube, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain the first reaction product. The first reaction product is precipitated in n-hexane, washed three times and dried to obtain a pink linear polymer PMMA-b-PAStBoc with a dithioester structure.

[0161] Take the above-mentioned linear polymer PMMA-b-PAStBoc with a dithioester structure in a test tube, add 0.02mmol azobisisobutyronitrile, 0.2mmol 4-chloromethylstyrene and 2mL dioxane, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h and then carry out polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain a second reaction product. The second reaction product is precipitated in n-hexane, washed three times and dried to obtain a pink linear polymer PMMA-b-PAStBoc-b-PVBC with a dithioester structure.

[0162] Take the above linear polymer PMMA-b-PAStBoc-b-PVBC with dithioester structure in a test tube and add 0.2 mmol NaN 3 , 5 mmol trifluoroacetic acid and 1 mL dimethylformamide were added and reacted 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 a linear polymer PMMA-b-PStNH with a dithioester structure and an azide terminal and a charge. 2 -b-PVBC.

[0163] Take the above-mentioned linear polymer PMMA-b-PStNH with a dithioester structure, azide at the end and charge 2 -b-PVBC was placed in a test tube, 1 mL of dimethylformamide was added to dissolve it, and then 0.2 mmol of catalyst triphenylphosphine was added. After stirring for 30 min, 0.6 mmol of catalyst triphenylphosphine was added and the mixture was heated to 40 °C for Staudinger reaction. The reaction lasted for 8 h to achieve cyclization. After the reaction was completed, saturated NaHCO 3 The charged groups are removed by washing and the precipitated polymer is dried in n-hexane at 60°C to remove triphenylphosphine, thereby obtaining a cyclic polymer having a dithioester structure.

[0164] Take the above cyclic polymer in a test tube, add 0.05mmol azobisisobutyronitrile, 10mmol styrene (St) and 2mL dioxane, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h and then carry out polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain the fourth reaction product. The fourth reaction product is precipitated in n-hexane, washed three times and dried to obtain a ring-chain hybrid structure polymer.

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

[0166]

[0167] Example 4

[0168] In a 50mL test tube, add 0.2mmol of 3-trimethylsilylpropynyl methacrylate (NMA), 0.02mmol of azobisisobutyronitrile, 0.1mmol of chain transfer agent CPADB, 10mmol of tert-butyl 4-vinylphenylcarbamate (AStBoc), and 2mL of dioxane, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain the first reaction product. The first reaction product is precipitated in n-hexane, washed three times and dried to obtain a pink linear polymer PNMA-b-PAStBoc with a dithioester structure.

[0169] Take the above-mentioned linear polymer PNMA-b-PAStBoc with a dithioester structure in a test tube, add 0.02mmol azobisisobutyronitrile, 0.2mmol 4-chloromethylstyrene and 2mL dioxane, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out the polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain a second reaction product. The second reaction product is precipitated in n-hexane, washed three times and dried to obtain a 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 NaN 3 , 5 mmol trifluoroacetic acid was added, and the reaction was continued 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 a linear polymer PNMA-b-PStNH having a dithioester structure, an azide group at the end group, and a charge. 2 -b-PVBC.

[0171] Take the above-mentioned linear polymer PNMA-b-PStNH with a dithioester structure, azide at the end and charge 2 -b-PVBC was placed in a test tube, 1 mL of dimethylformamide was added to dissolve it, and then 0.2 mmol of catalyst cuprous bromide was added to perform a click reaction at room temperature. The reaction lasted for 24 h to achieve cyclization. After the reaction was completed, saturated NaHCO 3 The charged groups were removed by washing and the copper ions were removed by dialysis with deionized water to prepare a cyclic polymer having a dithioester structure.

[0172] Take the above cyclic polymer in a test tube, add 0.05mmol azobisisobutyronitrile, 10mmol styrene (St) and 2mL dioxane, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain the fourth reaction product. The fourth reaction product is precipitated in n-hexane, washed three times and dried to obtain a ring-chain hybrid structure polymer.

[0173] Example 5

[0174] Add 0.2mmol hydroxyethyl methacrylate (HEMA), 0.02mg azobisisobutyronitrile, 0.1mL chain transfer reagent CPADB, 10mmol methacrylic acid (AA), and 2mL dioxane into a 50mL test tube, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out polymerization. After the reaction is completed, cool and terminate the reaction to obtain the first reaction product. The first reaction product is precipitated in n-hexane, washed three times and dried to obtain a linear polymer of pink PHEMA-b-PAA with a dithioester structure.

[0175] Take the above-mentioned pink PHEMA-b-PAA linear polymer with a dithioester structure in a test tube, add 0.02mmol azobisisobutyronitrile, 0.1mmol 4-chloromethylstyrene and 2mL dioxane, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out the polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain a second reaction product. The second reaction product is precipitated in n-hexane, washed three times and dried to obtain a pink linear polymer PHEMA-b-PAA-b-PVBC with a dithioester structure.

[0176] The pink linear polymer PHEMA-b-PAA-b-PVBC with a disulfide structure was placed in a test tube, 1 mL of dimethylformamide was added to dissolve it, and then 5 mmol of methylimidazole was added to introduce charges, and then 1% of triphenylphosphine palladium and 1% of cesium carbonate were added as catalysts to allow the linear polymer to undergo a coupling reaction at 80°C, and the coupling reaction was continued for 24 hours to achieve cyclization. After the coupling reaction was completed, 60°C n-hexane was used to precipitate the cyclic polymer and remove the charged groups, and then the cesium carbonate was removed by washing with water, and the cyclic polymer with a disulfide structure was obtained after drying.

[0177] Take the above cyclic polymer in a test tube, add 0.05mmol azobisisobutyronitrile, 10mmol styrene (St) and 2mL dioxane, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain the third reaction product. The third reaction product is precipitated in n-hexane, washed three times and dried to obtain a ring-chain hybrid structure polymer.

[0178] Example 6

[0179] Add 1mmol methyl methacrylate (MMA), 0.02mg azobisisobutyronitrile, 0.1mL chain transfer reagent CPADB, 10mmol 2-vinylpyridine (2VP), and 2mL dioxane to a 50mL test tube, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain the first reaction product. The first reaction product is precipitated in n-hexane, washed three times and dried to obtain a pink linear polymer PMMA-b-P2VP with a dithioester structure.

[0180] Take the above-mentioned pink linear polymer PMMA-b-P2VP with a dithioester structure in a test tube, add 0.02mmol azobisisobutyronitrile, 0.2mmol 4-chloromethylstyrene and 2mL dioxane, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out the polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain a second reaction product. The second reaction product is precipitated in n-hexane, washed three times and dried to obtain a pink linear polymer PMMA-b-P2VP-b-PVBC with a dithioester structure.

[0181] The pink linear polymer PMMA-b-P2VP-b-PVBC with dithioester structure was placed in a test tube and 0.2 mmol NaN was added. 3 , 10 mmol iodoethane and 1 mL dimethylformamide were added, and the reaction was continued for 24 h to obtain a third reaction product. The third reaction product was precipitated in n-hexane, washed three times, and dried to obtain PMMA-b-P2VP-b-PVBC having a dithioester structure and an azide terminal group and a charge.

[0182] The PMMA-b-P2VP-b-PVBC with a dithioester structure and an azide terminal and a charge was placed in a test tube, 1 mL of dimethylformamide was added to dissolve it, and then 0.2 mmol of catalyst triphenylphosphine was added. After stirring for 30 min, 0.6 mmol of catalyst triphenylphosphine was added and the mixture was heated to 40 °C for Staudinger reaction. The reaction lasted for 8 h to achieve cyclization. After the reaction was completed, saturated NaHCO 3 The charged groups are removed by washing and the precipitated polymer is dried in n-hexane at 60°C to remove triphenylphosphine, thereby obtaining a cyclic polymer having a dithioester structure.

[0183] Take the above cyclic polymer in a test tube, add 0.05mmol azobisisobutyronitrile, 10mmol styrene (St) and 2mL dioxane, stir evenly, and freeze-evacuate-thaw three times to deoxygenate. Heat at 80℃ for 8h to carry out polymerization reaction. After the reaction is completed, cool and terminate the reaction to obtain the fourth reaction product. The fourth reaction product is precipitated in n-hexane, washed three times and dried to obtain a ring-chain hybrid structure polymer.

[0184] Characterization

[0185] 1. GPC test

[0186] Gel permeation chromatography (GPC) test was performed on Example 3, and the results were as follows: Figure 1 shown. Figure 1 The following is a comparison of the gel permeation chromatography (GPC) curves of the linear polymer precursor (linear), cyclic polymer (cyclization) and ring-chain hybrid structure polymer (chain-joining) of Example 3 of the present invention. Figure 1 It can be seen that after cyclization, the GPC curve shifted slightly to the right, which is consistent with the characteristics of cyclic polymers. After the subsequent chain connection, the GPC curve shifted significantly to the left, which is consistent with the characteristics of ring-chain hybrid structure polymers.

[0187] 2. DLS test

[0188] Dynamic light scattering (DLS) test was performed on Example 3, and the results were as follows Figure 2 shown. Figure 2 The following is a comparison of the dynamic light scattering (DLS) data of the linear polymer precursor (linear), cyclic polymer (cyclization) and ring-chain hybrid structure polymer (chain-joining) of 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 the ring-chain hybrid structure polymer is formed, the average particle size is larger than that of the linear polymer precursor, which further illustrates that the method of the present invention prepares the ring-chain hybrid structure polymer.

[0189] 3. TEM test

[0190] The sample image of the ring-chain hybrid structure polymer was observed using a transmission electron microscope. The ring-chain hybrid structure polymer was visualized by grafting PEO-CHO with Mn=1000. Figure 3 The sample picture of the ring-chain hybrid structure polymer observed under a transmission electron microscope in Example 3 of the present invention is shown. Figure 3 It can be seen that the method of the present invention prepares a ring-chain hybrid structure polymer.

[0191] Industrial Applicability

[0192] As a kind of polymer colloidal nanoparticles with special structure, cyclic polymers can realize the functional coupling of the two after forming a ring-chain hybrid structure polymer. For example, by taking advantage of the characteristics of cyclic polymers that they are entangled-free and can pass through specific organs, the polymer chain can be used as a drug carrier to achieve drug loading and delivery at the same time. Targeting groups can also be introduced into the chain, so that the whole has a targeted recognition function, which has application value in cancer cell targeting and lesion removal. In addition, biological imaging can be achieved by loading fluorescent groups, which has application potential 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 is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0194] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing a ring-chain hybrid structure polymer, characterized in that: The following steps are involved: Obtaining a linear polymer precursor, wherein the linear polymer precursor has a group A, a group B, and a side group F, and the linear polymer precursor has a thioester bond structure; combining compound D with at least part of the side groups F of the linear polymer precursor to convert at least part of the side groups of the linear polymer precursor into charged groups; Allowing the group A to undergo a ring-closing reaction with the group B to form a charged cyclic polymer having a thioester bond structure; optionally removing the charged group to obtain a cyclic polymer; The cyclic polymer is polymerized using a thioester bond structure to obtain a ring-chain hybrid structure polymer.

2. The preparation method according to claim 1, characterized in that: The group A is selected from one or a combination of two or more of an azide group, a halogen group, a substituted or unsubstituted alkenyl group or a thiol group; and / or, The group B is selected from one or a combination of two or more of a substituted or unsubstituted alkynyl group, an ester group, a halogen group, a hydroxyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted amide group, a substituted or unsubstituted alkenyl group or a thiol group; and / or The side group F is selected from one or a combination of two or more of a carboxyl group, an amino group, a halogen group, a tertiary amine group, a pyridyl group, and an imidazole group.

3. The preparation method according to claim 1 or 2, characterized in that: The number average molecular weight of the linear polymer precursor is 5000 g / mol-200000 g / mol, preferably 10000 g / mol-100000 g / mol.

4. The preparation method according to any one of claims 1 to 3, characterized in that The compound D comprises one or a combination of two or more selected from carboxylic acid compounds, amino compounds, halogenated compounds, tertiary amine compounds, pyridine compounds, and imidazole compounds; and / or, The compound D reacts with the linear polymer precursor through a quaternization reaction or a salt-forming reaction to convert at least part of the side groups F of the linear polymer precursor into charged groups.

5. The preparation method according to any one of claims 1 to 4, characterized in that: 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, and more preferably, the dithioester derivative or the trithioester derivative has one or a combination of two or more of a hydroxyl group, an amino group, a halogen group, an ester group, and a carboxyl group.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The ring-closing reaction includes one or a combination of two or more of a click reaction, a Staudinger reaction, and a coupling reaction.

7. The preparation method according to any one of claims 1 to 6, characterized in that: In the preparation system, the concentration of the linear polymer precursor is 0.1 to 300 mg / mL, preferably 10 to 100 mg / mL.

8. The preparation method according to any one of claims 1 to 7, characterized in that: 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.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The ring-closing reaction is carried out in a solvent; preferably, the dielectric constant of the solvent is 2.2-49, preferably 2.6-37.

10. A ring-chain hybrid structure polymer, characterized in that: The polymer is prepared by the method for preparing a ring-chain hybrid structure polymer according to any one of claims 1 to 9. Preferably, the diameter of the ring in the ring-chain hybrid structure polymer is 3-100 nm.

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