Process for the preparation of block copolymers and block copolymers obtained therefrom

Abstract

The invention relates to a process for preparing a block copolymer, the process comprising: a) adding at least one ethylenically unsaturated hydrophilic monomer and a composition Y to a reactor for polymerization; b) adding at least one ethylenically unsaturated hydrophobic monomer to the reactor for polymerization after the polymerization of step a) to obtain an amphiphilic diblock copolymer; c) adding at least one ethylenically unsaturated hydrophobic monomer to the reactor for polymerization after the polymerization of step b); wherein the composition Y contains: A) at least one halogen molecule or halogenated hydrocarbon optionally substituted by cyano, B) at least one iodide salt, and C) at least one free radical polymerization initiator, wherein the equivalent ratio of the at least one ethylenically unsaturated hydrophobic monomer in step b) to the polymer formed from the at least one ethylenically unsaturated hydrophilic monomer in step a) is in the range of 5 to 60.

Description

Technical Field

[0001] This invention relates to a method for preparing block copolymers and the block copolymers obtained therefrom. Background Technology

[0002] Emulsion polymerization is a widely adopted technology for the industrial production of polymer dispersions, finding broad applications in numerous fields such as coatings, adhesives, textiles, and paints. Its significant advantages include ease of operation, high monomer conversion rates, precise control over particle size and morphology, and the ability to generate a wide variety of polymer types with customized properties. A typical emulsion polymerization process begins with the formation of micelles or vesicles, where surfactants (or emulsifiers, such as low-molecular-weight sodium dodecyl sulfate) assemble at the water-oil interface, effectively reducing interfacial tension and providing stabilization for monomer droplets. However, the use of surfactants carries inherent risks, such as surfactant segregation, which can potentially lead to particle aggregation. Furthermore, completely removing surfactants from the polymer has proven challenging.

[0003] Living radical polymerization (LRP) (also known as reversible deactivating radical polymerization (RDRP)), such as reversible addition-fragmentation chain transfer (RAFT) polymerization, nitroxide radical controlled polymerization (NMP), and atom transfer radical polymerization (ATRP), can control the composition, structure, molecular weight, and molecular weight distribution of polymers.

[0004] However, potential limitations remain, such as the use of transition metals as catalysts in ATRP, the odor of sulfur compounds used in RAFT, and the high temperatures required in NMP. This cumbersome and inefficient method hinders the scale-up preparation of nanomaterials and limits their potential commercial applications.

[0005] Therefore, there is a strong desire to develop a new polymerization route for preparing block polymers to obtain block copolymer emulsions with high solids content (up to 45% w / w), high monomer conversion, high molecular weight, and controllable particle size and polydispersity index. Summary of the Invention

[0006] The object of this invention is to provide a method for preparing block copolymers. The method of this invention allows for the production of block copolymer emulsions with high solids content (up to 45% w / w), high monomer conversion, high molecular weight, and controllable particle size and polydispersity index.

[0007] Another object of the present invention is to provide a block copolymer obtained by the method of the present invention.

[0008] It has been unexpectedly discovered that the above objectives can be achieved through the following embodiments:

[0009] 1. A method for preparing a block copolymer, comprising:

[0010] a) Add at least one olefinically unsaturated hydrophilic monomer and composition Y to a reactor for polymerization;

[0011] b) After the polymerization in step a), at least one olefinic unsaturated hydrophobic monomer is added to the reactor for polymerization to obtain an amphiphilic diblock copolymer;

[0012] c) After the polymerization in step b), at least one olefinic unsaturated hydrophobic monomer is added to the reactor for polymerization;

[0013] The composition Y contains:

[0014] A) At least one halogen molecule or a haloalkane optionally substituted with a cyano group.

[0015] B) At least one iodide salt, and

[0016] C) At least one free radical polymerization initiator,

[0017] The equivalent ratio of the at least one olefinic unsaturated hydrophobic monomer in step b) to the polymer formed from the at least one olefinic unsaturated hydrophilic monomer in step a) is in the range of 5 to 60.

[0018] 2. The method according to Example 1, wherein the haloalkane is selected from organofluorine compounds, organochlorine compounds, organobromine compounds and organoiodine compounds, which may optionally be substituted with a cyano group; and the halogen molecule is selected from molecular fluorine, molecular chlorine, molecular bromine and molecular iodine.

[0019] 3. The method according to any one of Examples 1 or 2, wherein the haloalkane is an alkyl iodine optionally substituted with a cyano group, preferably 2-iodo-2-methylpropionitrile; and the halogen molecule is molecular iodine.

[0020] 4. The method according to any one of Examples 1 to 3, wherein the iodide salt comprises an organic iodide salt and / or a water-soluble iodide salt, preferably a water-soluble inorganic iodide salt.

[0021] 5. The method according to Example 4, wherein the composition Y in step a) comprises the at least one water-soluble iodide salt and the at least one organic iodide salt; or the composition Y in step a) comprises the at least one water-soluble iodide salt, and at least one organic iodide salt is added in step b).

[0022] 6. The method according to Example 4 or 5, wherein the organic iodide salt is selected from substituted ammonium iodide and substituted phosphorus iodide, preferably from tetraalkylammonium iodide and tetraalkylphosphonium iodide, wherein the hydrocarbon group is independently a straight-chain or branched C1-C group each time it appears. 20 -alkyl or C6-C 20 -Aryl, preferably the hydrocarbon group is a straight-chain or branched C2-C8-alkyl.

[0023] 7. The method according to any one of Examples 4 to 6, wherein the water-soluble iodide salt is selected from iodides of alkaline earth metals, alkali metals and ammonium, preferably from lithium iodide, sodium iodide, potassium iodide, calcium iodide and ammonium iodide.

[0024] 8. The method according to any one of Examples 1 to 7, wherein the free radical polymerization initiator is an azo polymerization initiator, preferably selected from 2,2'-azobis(2-methylpropanediamine) dihydrochloride, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylpropanenitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis-2,3-dimethylbutyronitrile, 2,2-azobis-2,3,3-trimethyl... The free radical polymerization initiator is selected from 2,2'-azobis-2-isopropylbutyronitrile, 2,2'-azobis-(2,4,4-trimethylpentane), and 1,1'-azobis(cyclohexanenitrile), more preferably from 2,2'-azobis(2-methylpropanenitrile) dihydrochloride, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylpentanenitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylpentanenitrile).

[0025] 9. The method according to any one of Examples 1 to 7, wherein the free radical polymerization initiator is a peroxide or a reduction-oxidation initiator system, preferably the peroxide is selected from tert-butyl hydroperoxide (TBHP), tert-amyl hydroperoxide (TAHP), cumyl hydroperoxide, di-tert-butyl-peroxide and di-tert-amyl-peroxide; and preferably the reduction-oxidation initiator system comprises a peroxide and a reducing agent.

[0026] 10. The method according to any one of Examples 1 to 9, wherein the polymerization in steps a), b) and c) is carried out by reversible complexation-mediated polymerization (RCMP).

[0027] 11. The method according to any one of Examples 1 to 10, wherein the hydrophilic monomer in step a) is selected from monoene-bonded unsaturated hydrophilic monomers, especially monoene-bonded unsaturated hydrophilic monomers containing amide groups; monoene-bonded unsaturated hydrophilic monomers containing at least one acidic group selected from -COOH, -SO3H and -PO3H2 and their salts; and monoene-bonded unsaturated hydrophilic monomers containing hydroxyl and / or ether groups; preferably, the hydrophilic monomer is selected from monoene-bonded unsaturated hydrophilic monomers containing at least one acidic group selected from -COOH, -SO3H and -PO3H2 and their salts, N-methyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, (meth)acrylate C1-C6 hydroxyalkyl ester, allyl alcohol, hydroxyvinyl C1-C6 alkyl ether and poly(ethylene glycol) C1-C6 alkyl ether (meth)acrylate; and more preferably, step a) The hydrophilic monomer is a monoene-bonded unsaturated hydrophilic monomer and its salt containing at least one acidic group selected from -COOH, -SO3H and -PO3H2.

[0028] 12. The method according to any one of Examples 1 to 11, wherein the hydrophobic monomers in steps b) and c) are each independently selected from conjugated dienes having 4 to 22 carbon atoms, (meth)acrylic acid C1-C 20 Alkyl esters, (meth)acrylic acid C3-C 20 Cycloalkyl esters, (meth)acrylic acid C6-C 20 Aryl esters, styrene, styrene mono- or poly-substituted with C1-C5 alkyl groups, vinyl esters of carboxylic acids having up to 20 carbon atoms; more preferably, the hydrophobic monomer is selected from (meth)acrylic acid C1-C5. 20 Alkyl esters, (meth)acrylic acid C3-C 20 Cycloalkyl esters, (meth)acrylic acid C6-C 20 Aryl esters, styrene, and styrene mono- or poly-substituted with C1-C5 alkyl groups.

[0029] 13. The method according to any one of Examples 1 to 12, wherein the equivalent ratio of the at least one olefinically unsaturated hydrophobic monomer in step b) to the polymer formed from the at least one olefinically unsaturated hydrophilic monomer in step a) is in the range of 8 to 40, preferably 10 to 30, such as 10 to 20.

[0030] 14. The method according to any one of Examples 1 to 13, wherein the weight ratio of the at least one olefinic unsaturated hydrophobic monomer in step b) to the at least one olefinic unsaturated hydrophobic monomer in step c) is in the range of 1:2 to 1:400, preferably 1:5 to 1:200, more preferably 1:10 to 1:100.

[0031] 15. The method according to any one of Examples 1 to 14, wherein the polymerization in steps a), b) and c) is carried out under stirring.

[0032] 16. The method according to any one of Examples 1 to 15, wherein,

[0033] In step a), the amount of the at least one olefinic unsaturated hydrophilic monomer is in the range of 0.5 wt% to 30 wt%, preferably 1 wt% to 20 wt%, and more preferably 1.5 wt% to 10 wt%.

[0034] In step b), the amount of the at least one olefinic unsaturated hydrophobic monomer is in the range of 0.5 wt% to 30 wt%, preferably 1 wt% to 20 wt%, more preferably 1.5 wt% to 10 wt%; and

[0035] In step c), the amount of the at least one olefinic unsaturated hydrophobic monomer is in the range of 40 wt% to 99 wt%, preferably 60 wt% to 98 wt%, and more preferably 80 wt% to 97 wt%.

[0036] In each case, it is based on the total weight of these monomers.

[0037] 17. The method according to any one of Examples 1 to 16, wherein no surfactant is used.

[0038] 18. The method according to any one of Examples 1 to 17, wherein the polymerization in steps a), b) and c) is carried out in water.

[0039] 19. A block copolymer obtained by the method according to any one of Examples 1 to 18.

[0040] The method of this invention allows for the production of block copolymer emulsions with high solids content (up to 45% w / w), high monomer conversion, high molecular weight, and controllable particle size and polydispersity index, especially narrow polydispersity index. Furthermore, the method of this invention does not require surfactants or organic solvents, and the polymerization time is short. Detailed Implementation

[0041] Unless otherwise defined, all technical and scientific terms used herein have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains. As used herein, unless otherwise stated, the following terms have the meanings assigned to them as follows.

[0042] The articles “a”, “an” and “the” mean one or more substances represented by the term following the article.

[0043] In the context of this disclosure, any specific value mentioned for a feature (including specific values ​​mentioned as endpoints in a range) may be recombinated to form a new range.

[0044] Further embodiments of the invention can be seen from the claims, description, and examples. It should be understood that the foregoing features of the subject matter of the invention and the features to be elaborated below can be used not only in the specific combinations indicated, but also in other combinations without departing from the scope of the invention.

[0045] Methods for preparing block copolymers

[0046] One aspect of the present invention relates to a method for preparing a block copolymer, comprising:

[0047] a) Add at least one olefinically unsaturated hydrophilic monomer and composition Y to a reactor for polymerization;

[0048] b) After the polymerization in step a), at least one olefinic unsaturated hydrophobic monomer is added to the reactor for polymerization to obtain an amphiphilic diblock copolymer;

[0049] c) After the polymerization in step b), at least one olefinic unsaturated hydrophobic monomer is added to the reactor for polymerization;

[0050] The composition Y contains:

[0051] A) At least one halogen molecule or a haloalkane optionally substituted with a cyano group.

[0052] B) At least one iodide salt, and

[0053] C) At least one free radical polymerization initiator,

[0054] The equivalent ratio of the at least one olefinic unsaturated hydrophobic monomer in step b) to the polymer formed from the at least one olefinic unsaturated hydrophilic monomer in step a) is in the range of 5 to 60.

[0055] In this invention, the polymerization in steps a), b) and c) is carried out by reversible complexation-mediated polymerization (RCMP).

[0056] Reversible complex-mediated polymerization (RCMP) is an organocatalyzed living radical polymerization. RCMP involves a monomer, a halogenated hydrocarbon (e.g., alkyl iodide (R–I)) as the initiating dormant substance, and an iodide salt as the catalyst. In RCMP, the dormant substance (e.g., polymer–I) forms a halogen-bonded complex (e.g., polymer–I…catalyst) with the catalyst, and the complex reversibly generates a growing radical (polymer–I…catalyst). ● RCMP may optionally involve a radical polymerization initiator to accelerate polymerization. RCMP does not require special end-capping agents or metals. The catalysts used in RCMP are non-toxic, odorless, and not very sensitive to air and humidity.

[0057] In the embodiments, the halogenated hydrocarbon is selected from organofluorine compounds, organochlorine compounds, organobromine compounds, and organoiodine compounds, preferably organobromine compounds and organoiodine compounds, more preferably organoiodine compounds, which may optionally be substituted with a cyano group. In a preferred embodiment, the organoiodine compound is an iodocarbon that may optionally be substituted with a cyano group. The halogenated hydrocarbon, such as an iodocarbon, may have 1 to 22 carbon atoms (e.g., 1, 2, 4, 6, 8, 12, 16, 18, 20, or 22 carbon atoms), for example, 1 to 18, 1 to 16, 1 to 12, 1 to 10, or 1 to 8 carbon atoms.

[0058] Examples of iodohydrocarbons may include methyl iodine, ethyl iodine, propyl iodine, isopropyl iodine, butyl iodine, and tert-butyl iodine; iodophenylmethane, iododiphenylmethane, iodotriphenylmethane, 2-iodo-1-phenylethane, 1-iodo-1-phenylethane, 1-iodo-1,1-diphenylethane, and diiodomethane.

[0059] In the embodiments, the haloalkane is an alkyl iodide optionally substituted with a cyano group. The alkyl group may have 1 to 22 carbon atoms (e.g., 1, 2, 4, 6, 8, 12, 16, 18, 20, or 22 carbon atoms), such as 1 to 18, 1 to 16, 1 to 12, 1 to 10, or 1 to 8 carbon atoms. In a preferred embodiment, the haloalkane is 2-iodo-2-methylpropionitrile.

[0060] In the embodiments, the halogen molecule is selected from molecular fluorine, molecular chlorine, molecular bromine and molecular iodine, preferably molecular bromine and molecular iodine, more preferably molecular iodine.

[0061] If a halogen molecule (e.g., molecular iodine) is used, it can be reacted with a free radical polymerization initiator (e.g., an azo polymerization initiator), and the reaction product is then added to the reactor for polymerization. The reaction time can range from 1 to 10 hours, or 2 to 8 hours. The reaction temperature can range from 30°C to 85°C, or 40°C to 75°C. The reaction can be carried out under an inert atmosphere. The molar ratio of the halogen molecule to the free radical polymerization initiator can range from 1:1 to 1:5, or 1:1 to 1:4, or 1:1 to 1:3. The reaction product can reduce costs.

[0062] In a preferred embodiment, a prepolymerization step is introduced to allow the halogen molecules to react fully with the free radical polymerization initiator in an aqueous environment at a reaction temperature of 40°C to 75°C for 2 to 8 hours, after which other reactants are added.

[0063] Iodide salts include organic iodide salts and / or water-soluble iodide salts, preferably water-soluble inorganic iodide salts.

[0064] Organic iodide salts are preferably organic solvent-soluble iodide salts. Examples of organic solvent-soluble iodide salts include substituted ammonium iodides (e.g., hydrocarbon-substituted ammonium iodides) and substituted phosphonium iodides (e.g., hydrocarbon-substituted phosphonium iodides), preferably those selected from tetraalkylammonium iodides and tetraalkylphosphonium iodides, wherein the hydrocarbon group is independently a straight-chain or branched C1-C chain each time it appears. 20 -alkyl or C6-C 20 -Aryl, preferably straight-chain or branched C1-C 10 -alkyl (e.g., straight-chain or branched C2-C8-alkyl), or C6-C 12 -Aryl. Combinations of organic solvent-soluble iodide salts can also be used in the method of the present invention. Preferably, the organic solvent-soluble iodide salt is selected from tetrabutylammonium iodide, tributylmethylphosphonium iodide, and tetra-n-octylammonium iodide.

[0065] Examples of water-soluble iodide salts (preferably water-soluble inorganic iodide salts) include alkali metal salts, alkaline earth metal salts, and ammonium salts, particularly lithium iodide, sodium iodide, potassium iodide, ammonium iodide, calcium iodide, and magnesium iodide. Preferably, the water-soluble iodide salt can be selected from lithium iodide, sodium iodide, potassium iodide, calcium iodide, and ammonium iodide.

[0066] In a preferred embodiment, composition Y in step a) comprises at least one water-soluble iodide salt and at least one organic iodide salt; or composition Y in step a) comprises at least one water-soluble iodide salt, and at least one organic iodide salt is added in step b).

[0067] In this disclosure, the free radical polymerization initiator is a thermally unstable compound that generates a carbon-centered free radical. In the embodiments, the free radical polymerization initiator is an azo polymerization initiator, preferably selected from 2,2'-azobis(2-methylpropanediamine) dihydrochloride, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylpropanenitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis-2,3-dimethylbutyronitrile, 2,2-azobis-2,3,3-trimethylbutyronitrile, and 2-phenylazobis(2,3,3-trimethylbutyronitrile). 2,4-Dimethyl-4-methoxypentanonitrile, 2,2'-azobis-2-isopropylbutyronitrile, 2,2'-azobis-(2,4,4-trimethylpentane), and 1,1'-azobis(cyclohexanenitrile), more preferably, the free radical polymerization initiator is selected from 2,2'-azobis(2-methylpropanediamine) dihydrochloride, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylpentanonitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile). According to the present invention, the free radical polymerization initiator can be a water-soluble free radical polymerization initiator. The azo polymerization initiator can be a water-soluble azo polymerization initiator.

[0068] In another embodiment, the free radical polymerization initiator is a peroxide or a reduction-oxidation initiator system.

[0069] Suitable peroxides can be inorganic peroxides, such as hydrogen peroxide or persulfate, monoalkali metal or dialkali metal salts or ammonium salts such as persulfate, for example, monosodium and disodium salts, monopotassium salts or ammonium salts, such as sodium persulfate (NaPs); or organic peroxides, such as alkyl hydroperoxides, such as tert-butyl hydroperoxide (TBHP), tert-amyl hydroperoxide (TAHP), or cumyl hydroperoxide, and also dialkyl or diaryl peroxides, such as di-tert-butyl peroxide, di-tert-amyl peroxide, or dicumyl peroxide. Preferably, the peroxide is selected from tert-butyl hydroperoxide (TBHP), tert-amyl hydroperoxide (TAHP), cumyl hydroperoxide, di-tert-butyl-peroxide, and di-tert-amyl-peroxide.

[0070] Preferably, the reduction-oxidation initiator system comprises a peroxide and a reducing agent. Reducing agents that can be used in redox initiator systems are sulfur compounds with low oxidation states, such as alkali metal sulfites, for example, potassium sulfite and / or sodium sulfite; alkali metal bisulfites, for example, potassium bisulfite and / or sodium bisulfite, such as NaHSO3; alkali metal metabisulfites, for example, potassium metabisulfite and / or sodium metabisulfite, such as sodium metabisulfite (SMBS), sodium acetone bisulfite (SAB); formaldehyde bisulfite, for example, potassium formaldehyde bisulfite and / or sodium formaldehyde bisulfite, such as sodium formaldehyde bisulfite (SFS); alkali metal salts of aliphatic sulfinic acids, specifically potassium and / or sodium salts; and alkali metal hydrosulfides, such as potassium and / or sodium hydrosulfide; salts of polyvalent metals, such as ferric(II) sulfate, ammonium ferric(II) sulfate, ferric(II) phosphate; ethylene glycols, such as dihydroxymaleic acid, benzoic acid; and reducing sugars, such as ascorbic acid, sodium ascorbate, sorbitol, glucose, fructose and / or dihydroxyacetone.

[0071] In the embodiments, the molar ratio of halogen molecules or haloalkanes, calculated in terms of halogen atoms (e.g., iodine atoms, if molecular iodine or alkyl iodine is used), to the free radical polymerization initiator is in the range of 1:5 to 5:1 (e.g., 1:4, 1:3, 1:2, 1:1, 2:1, 3:3 or 4:1), preferably 1:3 to 3:1, or 2:1 to 1:2.

[0072] In the embodiments, the molar ratio of halogen molecules or haloalkanes to iodide salts, calculated in terms of halogen atoms (e.g., iodine atoms, if molecular iodine or alkyl iodine is used), is in the range of 10:1 to 1:1 (e.g., 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1 or 2:1), preferably 6:1 to 2:1.

[0073] In the embodiments, the molar ratio of the free radical polymerization initiator to the iodide salt is in the range of 10:1 to 1:2 (e.g., 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, or 1:1), preferably 6:1 to 1:1, or 5:1 to 1.2:1.

[0074] Based on the total weight of composition Y, the amount of halogen molecules or haloalkanes can be in the range of 5 wt% to 60 wt% (e.g., 8 wt%, 10 wt%, 15 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, or 55 wt%), preferably 10 wt% to 50 wt%.

[0075] Based on the total weight of composition Y, the amount of iodide salt can be in the range of 5 wt% to 50 wt% (e.g., 8 wt%, 10 wt%, 15 wt%, 20 wt%, 30 wt%, 40 wt%, or 45 wt%), preferably 10 wt% to 40 wt%.

[0076] Based on the total weight of composition Y, the amount of free radical polymerization initiator (e.g., azo polymerization initiator) can be in the range of 10 wt% to 80 wt% (e.g., 15 wt%, 20 wt%, 25 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt% or 75 wt%), preferably 20 wt% to 75 wt% or 25 wt% to 75 wt%.

[0077] In the embodiments, composition Y contains:

[0078] A) Molecular iodine or alkyl iodine optionally substituted with a cyano group.

[0079] B) Organic iodide salts and water-soluble iodide salts, and

[0080] C) At least one azo polymerization initiator.

[0081] In the embodiments, composition Y contains:

[0082] A) Molecular iodine or optionally cyano-substituted alkyl iodine in amounts of 5 wt% to 60 wt%, preferably 10 wt% to 50 wt%,

[0083] B) Organic iodide salts and water-soluble iodide salts in amounts of 5 wt% to 50 wt%, preferably 10 wt% to 40 wt%, and

[0084] C) At least one azo polymerization initiator in an amount of 10 wt% to 80 wt%, preferably 20 wt% to 70 wt%,

[0085] In each case, the total weight of composition Y is taken into account.

[0086] In the embodiments, the composition Y in step a) contains:

[0087] A) At least one halogen molecule, preferably a molecular iodine or a haloalkane optionally substituted with a cyano group, preferably an alkyl iodine optionally substituted with a cyano group.

[0088] B) Water-soluble iodide salts, preferably water-soluble inorganic iodide salts, and

[0089] C) At least one free radical polymerization initiator, preferably an azo polymerization initiator.

[0090] And in step b), at least one organic iodide salt, preferably tetraalkylammonium iodide, is added.

[0091] In the embodiments, the composition Y in step a) contains:

[0092] A) At least one halogen molecule, preferably molecular iodine or optionally cyano-substituted alkyl iodine, in amounts of 5 wt% to 60 wt%, preferably 10 wt% to 55 wt%, in a cyano-substituted amount.

[0093] B) A water-soluble iodide salt, preferably a water-soluble inorganic iodide salt, in amounts of 4 wt% to 25 wt%, preferably 5 wt% to 20 wt%, and...

[0094] C) At least one free radical polymerization initiator, preferably an azo polymerization initiator, in an amount of 10 wt% to 80 wt%, preferably 20 wt% to 75 wt%.

[0095] Based on the total weight of composition Y in each case,

[0096] And in step b), the at least one organic iodide salt, preferably tetraalkylammonium iodide, is added in an amount of 10 wt% to 40 wt%, preferably 12 wt% to 35 wt%, based on the total weight of composition Y.

[0097] In the embodiments, the composition Y in step a) contains:

[0098] A) At least one halogen molecule, preferably a molecular iodine or a haloalkane optionally substituted with a cyano group, preferably an alkyl iodine optionally substituted with a cyano group.

[0099] B) Organic iodide salts, preferably tetraalkylammonium iodide and water-soluble iodide salts, preferably water-soluble inorganic iodide salts, and

[0100] C) At least one free radical polymerization initiator, preferably an azo polymerization initiator.

[0101] According to the present invention, each component in composition Y can be added individually to the reactor.

[0102] Step a) The hydrophilic monomer is selected from monoene-bonded unsaturated hydrophilic monomers, especially monoene-bonded unsaturated hydrophilic monomers containing amide groups; monoene-bonded unsaturated hydrophilic monomers containing at least one acidic group selected from -COOH, -SO3H and -PO3H2 and their salts; and monoene-bonded unsaturated hydrophilic monomers containing hydroxyl and / or ether groups. Preferably, the hydrophilic monomer is selected from monoene-bonded unsaturated hydrophilic monomers containing at least one acidic group selected from -COOH, -SO3H and -PO3H2 and their salts, N-methyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, (meth)acrylate C1-C6 hydroxyalkyl ester, allyl alcohol, hydroxyvinyl C1-C6 alkyl ether and poly(ethylene glycol) C1-C6 alkyl ether (meth)acrylate, most preferably monoene-bonded unsaturated hydrophilic monomers containing at least one acidic group selected from -COOH, -SO3H and -PO3H2 and their salts.

[0103] The mono-olefinic unsaturated hydrophilic monomers containing -SO3H are 1-acrylamido-1-propanesulfonic acid, 2-acrylamido-2-propanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, 3-methacrylamido-2-hydroxypropanesulfonic acid, allylsulfonic acid, methylallylsulfonic acid, allyloxybenzenesulfonic acid, methylallyloxybenzenesulfonic acid, 2-hydroxy-3-(2-acryloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, styrenesulfonic acid, vinylsulfonic acid, 3-sulfopropyl acrylate, 2-sulfoethyl methacrylate, 3-sulfopropyl methacrylate, sulfomethacrylamide, sulfomethylmethacrylamide, and salts of said acids, such as their sodium, potassium, or ammonium salts.

[0104] Mono-olefin unsaturated hydrophilic monomers containing -COOH are olefin unsaturated carboxylic acids having 3 to 8 carbon atoms, such as acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, citralic acid, and salts of said acids, such as their sodium, potassium, or ammonium salts.

[0105] Monoolefinic unsaturated hydrophilic monomers containing -PO3H2 are, for example, ethyl methacrylate and ethyl acrylate.

[0106] The monoolefinic unsaturated hydrophilic monomer containing a hydroxyl group can be (meth)acrylic acid C1 to C1. 10Hydroxyalkyl esters, such as C1 to C8 hydroxyalkyl esters or C1 to C6 hydroxyalkyl esters of (meth)acrylate, including, for example, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 3-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, or 3-hydroxy-2-ethylhexyl methacrylate, etc.

[0107] Based on the total weight of the monomers, the amount of the at least one olefinic unsaturated hydrophilic monomer in step a) is in the range of 0.5 wt% to 30 wt% (e.g., 0.8 wt%, 1 wt%, 1.5 wt%, 1.8 wt%, 2 wt%, 2.5 wt%, 3 wt%, 5 wt%, 6 wt%, 8 wt%, 10 wt%, 15 wt%, 20 wt%, or 25 wt%), preferably 1 wt% to 20 wt%, more preferably 1.5 wt% to 10 wt% or 1.8 wt% to 6 wt%.

[0108] The hydrophobic monomers in steps b) and c) are each independently selected from conjugated dienes having 4 to 22 carbon atoms, C1-C of (meth)acrylic acid. 20 Alkyl esters, (meth)acrylic acid C3-C 20 Cycloalkyl esters, (meth)acrylic acid C6-C 20 Aryl esters, styrene, styrene mono- or poly-substituted with C1-C5 alkyl groups, and vinyl esters of carboxylic acids having up to 20 carbon atoms; more preferably, the hydrophobic monomer is selected from (meth)acrylic acid C1-C5. 20 Alkyl esters, (meth)acrylic acid C3-C 20 Cycloalkyl esters, (meth)acrylic acid C6-C 20 Aryl esters, styrene, styrene mono- or poly-substituted with C1-C5 alkyl groups, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate (i.e., lauryl (meth)acrylate), tetradecyl (meth)acrylate, oleyl (meth)acrylate, palmitate (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, styrene, α-methylstyrene, o-, m- and p-methylstyrene, o-, m- and p-ethylstyrene, o-, p-dimethylstyrene, o-, p-diethylstyrene, isopropylstyrene and o-methyl-p-isopropylstyrene.

[0109] Conjugated dienes having 4 to 22 carbon atoms (e.g., 4 to 12 carbon atoms) can be butadiene or isoprene.

[0110] (Meth)acrylic acid C1 to C1 20 Alkyl esters (e.g., (meth)acrylic acid C1 to C1) 12 Specific examples of alkyl esters and (meth)acrylates (C1 to C6 alkyl esters) may include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, sec-butyl (meth)acrylate, amyl (meth)acrylate, n-hexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, n-tetane (meth)acrylate, n-cetyl (meth)acrylate, isomyristyl (meth)acrylate, stearyl (meth)acrylate, and isostearyl (meth)acrylate (ISTA).

[0111] (Meth)acrylic acid C3 to C 10 Cycloalkyl esters (e.g., (meth)acrylic acid C5 to C6) 10 Specific examples of cycloalkyl esters may include isobornyl acrylate, isobornyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, dicyclopentyl (meth)acrylate, or 3,3,5-trimethylcyclohexyl (meth)acrylate.

[0112] (Meth)acrylic acid C6-C 20 Aryl esters may include (meth)acrylic acid C6-C 10 Aryl esters, such as phenyl (meth)acrylate, benzyl (meth)acrylate, and ethyl (meth)acrylate.

[0113] Examples of vinyl esters of carboxylic acids having up to 20 carbon atoms (e.g., 2 to 20, or 8 to 18, or 2 to 8 carbon atoms) may include vinyl lauryl acid, vinyl stearate, vinyl propionate, and vinyl acetate.

[0114] Styrene mono- or poly-substituted with C1-C5 alkyl groups may include α-methylstyrene, o-, m- and p-methylstyrene, o-, m- and p-ethylstyrene, o-, p-dimethylstyrene, o-, p-diethylstyrene, isopropylstyrene and o-methyl-p-isopropylstyrene.

[0115] The hydrophobic monomers in steps b) and c) can be the same or different.

[0116] Based on the total weight of the monomers, the amount of the at least one olefinic unsaturated hydrophobic monomer in step b) is in the range of 0.5 wt% to 30 wt% (e.g., 0.8 wt%, 1 wt%, 1.5 wt%, 1.8 wt%, 2 wt%, 2.5 wt%, 3 wt%, 5 wt%, 6 wt%, 8 wt%, 10 wt%, 15 wt%, 20 wt%, or 25 wt%), preferably 1 wt% to 20 wt%, more preferably 1.5 wt% to 10 wt% or 1.8 wt% to 6 wt%.

[0117] Based on the total weight of the monomers, the amount of the at least one olefinic unsaturated hydrophobic monomer in step c) is in the range of 40 wt% to 99 wt% (e.g., 45 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 96 wt%, 97 wt%, or 98 wt%), preferably 60 wt% to 98 wt%, more preferably 80 wt% to 97 wt% or 85 wt% to 96 wt%.

[0118] In the embodiments, the amount of the at least one olefinic unsaturated hydrophilic monomer in step a) is in the range of 0.5 wt% to 30 wt%, preferably 1 wt% to 20 wt%, more preferably 1.5 wt% to 10 wt% or 1.8 wt% to 6 wt%.

[0119] In step b), the amount of the at least one olefinic unsaturated hydrophobic monomer is in the range of 0.5 wt% to 30 wt%, preferably 1 wt% to 20 wt%, more preferably 1.5 wt% to 10 wt% or 1.8 wt% to 6 wt%; and

[0120] In step c), the amount of the at least one olefinic unsaturated hydrophobic monomer is in the range of 40 wt% to 99 wt%, preferably 60 wt% to 98 wt%, more preferably 80 wt% to 97 wt% or 85 wt% to 96 wt%.

[0121] In each case, it is based on the total weight of these monomers.

[0122] According to the present invention, the equivalence ratio of the at least one olefinically unsaturated hydrophobic monomer in step b) to the polymer formed from the at least one olefinically unsaturated hydrophilic monomer in step a) is in the range of 5 to 60 (e.g., 8, 10, 12, 15, 20, 30, 40, 50 or 55), preferably 8 to 40, more preferably 10 to 30, or 10 to 20. According to the present invention, the polymer formed from the at least one olefinically unsaturated hydrophilic monomer in step a) acts as a macromolecular initiator in step b).

[0123] In the embodiments, the molar ratio of the at least one olefinic unsaturated hydrophobic monomer to a halogen molecule (preferably molecular iodine) or optionally a cyano-substituted haloalkane (preferably alkyl iodine) in step b) is calculated in the range of 5 to 60 (e.g., 8, 10, 12, 15, 20, 30, 40, 50 or 55), preferably 8 to 40, more preferably 10 to 30, or 10 to 20 in halogen atoms (preferably iodine atoms).

[0124] In the embodiments, the molar ratio of the at least one olefinic unsaturated hydrophilic monomer to a halogen molecule (preferably molecular iodine) or optionally a cyano-substituted haloalkane (preferably alkyl iodine) in step a) is calculated in the range of 4 to 50 (e.g., 5, 6, 7, 8, 9, 10, 12, 15, 20, 30, 40 or 45), preferably 5 to 30, more preferably 6 to 20, or 7 to 15 in halogen atoms (preferably iodine atoms).

[0125] In the embodiments, the weight ratio of the at least one olefinic unsaturated hydrophilic monomer in step a) to the at least one olefinic unsaturated hydrophobic monomer in step b) is in the range of 4:1 to 1:4, preferably 3:1 to 1:3, more preferably 2:1 to 1:2, and most preferably 1.5:1 to 1:1.5.

[0126] In the embodiments, the weight ratio of the at least one olefinically unsaturated hydrophobic monomer in step b) to the at least one olefinically unsaturated hydrophobic monomer in step c) is in the range of 1:2 to 1:400 (e.g., 1:5, 1:8, 1:10, 1:20, 1:50, 1:80, 1:100, 1:150, 1:200, 1:250, 1:300, 1:350 or 1:380), preferably 1:5 to 1:200, and more preferably 1:10 to 1:100.

[0127] The polymerization in steps a), b), and c) is carried out under stirring.

[0128] The polymerization temperature in step a) can be in the range of 35°C to 90°C, preferably 45°C to 80°C. The polymerization time in step a) can be in the range of 0.4 to 2 hours, preferably 0.6 to 1 hour.

[0129] The polymerization temperature in step b) can be in the range of 40°C to 90°C, preferably 50°C to 85°C. The polymerization time in step b) can be in the range of 0.4 to 2 hours, preferably 0.6 to 1 hour.

[0130] The polymerization temperature in step c) can be in the range of 35°C to 90°C, preferably 45°C to 80°C. The polymerization time in step c) can be in the range of 0.8 to 7 hours (e.g., 1, 2, 3, 4, 5, 6 or 6.5 hours), or 1 to 3 hours.

[0131] The polymerization in steps a), b), and c) can be carried out in an inert atmosphere.

[0132] According to the present invention, surfactants are not necessary. In the embodiments, surfactants are not used in the method of the present invention.

[0133] According to the present invention, the polymerization in steps a), b) and c) is carried out in water.

[0134] According to the present invention, an emulsion is formed after polymerization in step b).

[0135] In an embodiment, the present invention relates to a method for preparing a block copolymer, comprising:

[0136] a) A composition Y, comprising at least one olefinic unsaturated hydrophilic monomer and at least one halogenated hydrocarbon optionally substituted with a cyano group, at least one iodide salt and at least one free radical polymerization initiator, is added to a reactor for polymerization.

[0137] b) After polymerization in step a), at least one olefinic unsaturated hydrophobic monomer and at least one iodide salt are added to the reactor for polymerization to obtain an amphiphilic diblock copolymer;

[0138] c) After polymerization in step b), at least one olefinic unsaturated hydrophobic monomer is added to the reactor for polymerization;

[0139] The polymerization in steps a), b), and c) is carried out via reversible complexation-mediated polymerization (RCMP); and

[0140] The equivalent ratio of the at least one olefinic unsaturated hydrophobic monomer in step b) to the polymer formed from the at least one olefinic unsaturated hydrophilic monomer in step a) is in the range of 5 to 60.

[0141] In an embodiment, the present invention relates to a method for preparing a block copolymer, comprising:

[0142] a) A composition Y comprising at least one olefinically unsaturated hydrophilic monomer and at least one alkyl iodine optionally substituted with a cyano group, at least one water-soluble iodide salt and at least one azo polymerization initiator is added to a reactor for polymerization.

[0143] b) After polymerization in step a), at least one olefinic unsaturated hydrophobic monomer and at least one organic iodide salt are added to the reactor for polymerization to obtain an amphiphilic diblock copolymer.

[0144] c) After polymerization in step b), at least one olefinic unsaturated hydrophobic monomer is added to the reactor for polymerization;

[0145] The polymerization in steps a), b), and c) is carried out via reversible complexation-mediated polymerization (RCMP); and

[0146] The equivalent ratio of the at least one olefinic unsaturated hydrophobic monomer in step b) to the polymer formed from the at least one olefinic unsaturated hydrophilic monomer in step a) is in the range of 5 to 60.

[0147] In the embodiments, at least one halogenated hydrocarbon (e.g., alkyl iodine) that is optionally substituted with a cyano group in step a) is replaced by the reaction product of a halogen molecule (e.g., molecular iodine) and a free radical polymerization initiator (e.g., an azo polymerization initiator).

[0148] According to the present invention, the method is a one-pot process. In this respect, no intermediate separation is performed.

[0149] According to the present invention, the block copolymer can be obtained in the form of an emulsion. The solids content of the emulsion can be at least 35 wt%, at least 40 wt%, preferably at least 42 wt%, or at least 45 wt%, typically not exceeding 60 wt%, or not exceeding 55 wt%, or not exceeding 50 wt%, based on the total weight of the emulsion. The average particle size of the emulsion does not exceed 900 nm (e.g., 850 nm, 800 nm, 700 nm, 600 nm, 500 nm, 400 nm, 300 nm, 200 nm), preferably not exceeding 850 nm. The average particle size as mentioned herein refers to the Z-average particle size, as determined by dynamic light scattering (DLS). The measurement method is described in ISO 13321:1996.

[0150] polymer

[0151] The present invention further relates to a block copolymer obtained by the method according to the invention.

[0152] The block polymers obtained by the method of the present invention may have a number-average molecular weight of not less than 80,000 g / mol (e.g., 100,000 g / mol, 150,000 g / mol, 200,000 g / mol, 300,000 g / mol, 400,000 g / mol, 500,000 g / mol, 600,000 g / mol, or 800,000 g / mol), preferably not less than 100,000 g / mol, as measured by gel permeation chromatography (GPC).

[0153] The polymer obtained by the method of the present invention may have a polydispersity index (PDI of GPC, also expressed as GPC) of no more than 3.2 (e.g., 3.1, 3, 2.9, 2.8, 2.5, 2.4 or 2.2), preferably no more than 3. ), such as that measured by gel permeation chromatography (GPC).

[0154] As mentioned above, block copolymers can be in the form of emulsions.

[0155] The block copolymers or emulsions thereof of the present invention can be used in a variety of fields such as coatings, adhesives, textiles and paints.

[0156] Example

[0157] The invention will be better understood in light of the following non-limiting examples.

[0158] Materials and Abbreviations

[0159]

[0160] Measurement methods

[0161] Unless otherwise stated, the number-average molecular weight (M) of GPC is... nThe polydispersity index (PDI of GPC) and other parameters were determined by gel permeation chromatography (GPC) using DMF as the eluent. GPC analysis using DMF as the eluent was performed on a Shimadzu (Kyoto, Japan) LC-2030C plus liquid chromatograph equipped with two Shodex LF-804 columns (300 × 8.0 μm; bead size = 6 μm; pore size = 3000 Å) and one KD-802 column (300 × 8.0 μm; bead size = 6 μm; pore size = 150 Å). The eluent (DMF) contained LiBr (10 mM). The flow rate was 0.34 mL / min (40°C). Sample detection and quantification were performed using a Shimadzu RID-20A differential refractometer. The column system was calibrated using either poly(methyl methacrylate) (PMMA) or polystyrene (PSt) standards.

[0162] As mentioned herein, the average particle size refers to the Z-mean particle size, as determined by dynamic light scattering (DLS). The polydispersity index (PDI) of DLS is also determined by DLS. The measurement method is described in ISO 13321:1996. For this purpose, a sample of aqueous polymer latex is diluted, and the dilution is analyzed. In the context of DLS, depending on the particle size, the aqueous dilution can have a polymer concentration ranging from 0.001% to 0.5% by weight. For most purposes, a suitable concentration would be 0.01% by weight. However, higher or lower concentrations can be used to achieve the optimal signal-to-noise ratio. Dilution can be achieved by adding the polymer latex to an aqueous solution of water or a surfactant to avoid flocculation. Typically, dilution is performed using a 0.1% by weight aqueous solution of a nonionic emulsifier (e.g., ethoxylated C16 / C18 alkanols with a degree of ethoxylation of 18) as the diluent. Measurement configuration: HPPS from Malvern, automated, with continuous flow cuvettes and Gilson autosampler.

[0163] Parameters: Measurement temperature 20.0°C; Measurement time 120 seconds (6 cycles, 20 seconds each); Scattering angle 173°; Laser wavelength 633 nm (HeNe); Refractive index of the medium 1.332 (aqueous); Viscosity 0.9546 mPa⁻². The measurements yielded the average values ​​(fitted average values) from the second-order cumulant analysis, i.e., the Z-mean. The "fitted average value" is the intensity-weighted average hydrodynamic particle size in nm.

[0164] Monomer conversion rate percentage 1H NMR was used for determination. Recordings were taken at ambient temperature on a Bruker AV500 spectrometer (500 MHz) or AV300 (300 MHz) (Germany). 1 1H NMR spectroscopy. CDCl3 (for purified polymers), acetone-d6 (for crude methacrylate polymers), and tetrahydrofuran-d8 (for crude styrene polymers) (Cambridge Isotope Laboratories, USA) were used as solvents for NMR analysis, and the chemical shift was calibrated using residual undeuterated solvent or tetramethylsilane (TMS) as an internal standard.

[0165] Example 1: One-pot synthesis of triblock polymer emulsions using CP–I

[0166] 1) Synthesis of the triblock polymer PSSNa-PSt-PBA

[0167] Block 1: PSSNa–I was first synthesized using a mixture of SSNa (0.49 mM, monomer 1), 2-iodo-2-methylpropionitrile (CP–I) (0.058 mM, alkyl iodide initiator), 2,2'-azobis(2-methylpropanediamine) dihydrochloride (V50) (0.032 mM, azo initiator), sodium iodide (NaI) (0.019 mM, catalyst), and water (70 wt.%). The mixture was placed in a Schlenk tube, purged with a continuous argon flow for 5 min, and then heated at 60°C with magnetic stirring for 1 h. The first block PSSNa–I in water was then successfully prepared for use (monomer conversion > 95%). The target degree of polymerization (DP) at 100% monomer conversion, calculated according to [M]0 / [initiator / macromolecular initiator]0, was 8, and the actual DP was 19.

[0168] Block 2: Since V50 and NaI are already contained in the PSSNa–I aqueous solution, styrene (0.87 mM, monomer 2) and tetrabutylammonium iodide (Bu4N) are then added under a continuous argon flow. + I -A mixture of (BNI) (0.017 mM, catalyst) and water (70 wt.%, total monomer and macromolecular initiator 30 wt.%) was added directly to the tube to form the PSSNa–PSt–I emulsifier (amphiphilic diblock copolymer). After 1 hour of magnetic stirring at 70°C, the polymerization system became a homogeneous and slightly emulsifiable emulsion (monomer conversion > 90%). The target degree of polymerization (DP) of block 2 at 100% monomer conversion, calculated according to [M]0 / [initiator / macromolecular initiator]0, was 15. As shown in entry 2 of Table 1, the equivalent ratio of St to PSSNa–I was 8000 / 532, approximately 15.

[0169] Block 3: Subsequently, a mixture of butyl acrylate (BA) (27.2 mM, monomer 3) and water (55 wt.%, the total amount of monomer and macromolecular initiator is 45 wt.%) was added under a continuous argon flow. The mixture was then purged with a continuous argon flow for 5 min and heated at 60°C with magnetic stirring for 2 h. 1 ¹H-NMR, GPC, and DLS analyses were performed on the final emulsion polymer (monomer conversion > 90%) to determine monomer conversion, molecular weight, and particle size (Table 1, entries 1-3). The final emulsion had a solids content of 45 wt.% and a Z-mean size (d.nm) of 796 nm.

[0170] 2) Synthesis of the triblock copolymer PSSNa-PSt-PSt

[0171] The synthesis of the triblock copolymer PSSNa-PSt-PSt was similar to that of the triblock copolymer PSSNa-PSt-PBA described above, except that the conditions listed in item 4 of Table 1 were used for block 3. The final emulsion had a solids content of 45 wt.% and a Z-average size (d.nm) of 236 nm.

[0172] 3) Synthesis of the triblock copolymer PSSNa-PSt-PBzMA

[0173] The synthesis of the triblock copolymer PSSNa-PSt-PBzMA was similar to that of the triblock copolymer PSSNa-PSt-PBA described above, except that the conditions for block 3 were as listed in item 5 of Table 1. The final emulsion had a solids content of 45 wt.% and a Z-average size (d.nm) of 311 nm.

[0174] Table 1. One-pot synthesis of triblock polymer emulsions using CP–I

[0175] Segment 1:

[0176]

[0177] Segment 2:

[0178]

[0179] Segment 3:

[0180]

[0181] a. The numbers in parentheses are the actual ratios, i.e., the sum of this step and the previous steps. b. The theoretical M calculated based on [M]0, [initiator / macromolecule initiator]0, and monomer conversion. n value.

[0182] Example 2: One-pot synthesis of azo / I2 triblock polymer emulsion

[0183] 1) Synthesis of the triblock polymer PSSNa-PSt-PBA

[0184] Block 1: A mixture of iodine (I₂) (0.03 mM), 2,2'-azobis(2-methylpropanediamine) dihydrochloride (V50) (0.06 mM, azo initiator), and water was placed in a Schlenk tube, purged with a continuous argon flow for 5 min, and then heated at 60°C with magnetic stirring for 5–6 h (the height depends on the iodine powder size). When the solution became colorless and transparent (indicating the completion of the prepolymerization reaction), a mixture of SSNa (0.49 mM, monomer 1), V50 (0.032 mM, azo initiator), and sodium iodide (NaI) (0.019 mM, catalyst) was placed in a Schlenk tube, purged with a continuous argon flow for 5 min, and then heated at 60°C with magnetic stirring for 60 min. The first block PSSNa–I in water was then successfully prepared for use (monomer conversion > 90%). The target degree of polymerization (DP) calculated based on [SSNa]0 / 2[I2]0 at 100% monomer conversion is 8, and the actual DP is 14.

[0185] Block 2: Since V50 and NaI are already contained in the PSSNa–I aqueous solution, styrene (0.87 mM, monomer 2) and tetrabutylammonium iodide (Bu4N) are then added under a continuous argon flow. + I -A mixture of (BNI) (0.017 mM, catalyst) and water (70 wt.%, total monomer and macromolecular initiator 30 wt.%) was added directly to the tube to form the PSSNa–PSt–I emulsifier (amphiphilic diblock copolymer). After 1 hour of magnetic stirring at 70°C, the polymerization system became a homogeneous and slightly emulsified emulsion (monomer conversion > 90%). The target degree of polymerization (DP) of block 2 at 100% monomer conversion, calculated based on [St]0 / [PSSNa–I]0, was 15. As shown in entry 2 of Table 2, the equivalent ratio of St to PSSNa–I is 8000 / 532, approximately 15.

[0186] Block 3: Subsequently, a mixture of butyl acrylate (BA) (27.2 mM, monomer 3) and water (55 wt.%, the total amount of monomer and macromolecular initiator is 45 wt.%) was added under a continuous argon flow. The mixture was then purged with a continuous argon flow for 5 min and heated at 60°C with magnetic stirring for 2 h. 1 ¹H-NMR, GPC, and DLS analyses of the final emulsion polymer (monomer conversion > 85%) were performed to determine monomer conversion, molecular weight, and particle size (Table 2, entries 1-3). The final emulsion had a solids content of 45 wt.% and a Z-average size (d.nm) of 622 nm.

[0187] 2) Synthesis of the triblock copolymer PSSNa-PSt-PSt

[0188] The synthesis of the triblock copolymer PSSNa-PSt-PSt in Example 2 was similar to that of the triblock copolymer PSSNa-PSt-PBA in Example 2, except that the conditions listed in item 4 of Table 2 were used for block 3. The final emulsion had a solids content of 45 wt.% and a Z-average size (d.nm) of 247 nm.

[0189] 3) Synthesis of the triblock copolymer PSSNa-PSt-PBzMA

[0190] The synthesis of the triblock copolymer PSSNa-PSt-PBzMA in Example 2 was similar to that of the triblock copolymer PSSNa-PSt-PBA in Example 2, except that the conditions for block 3 were as listed in item 5 of Table 2. The final emulsion had a solids content of 45 wt.% and a Z-average size (d.nm) of 272 nm.

[0191] Table 2. One-pot synthesis of triblock polymer emulsions using I2 / azo polymers

[0192] Segment 1

[0193]

[0194] Segment 2

[0195]

[0196] Block 3

[0197]

[0198] a. The numbers in parentheses are the actual ratios, i.e., the sum of this step and the previous steps. b. The theoretical M calculated based on [M]0, [initiator / macromolecule initiator]0, and monomer conversion. n value.

[0199] Comparison Example 1:

[0200] Conventional RCMP emulsion polymerization (using commercially available emulsifiers Tween80 and FES77) was performed as a comparative example to demonstrate the advantages of the triblock polymerization technique of the present invention. For better comparison with our inventive technique (Table 2, entries 1, 2, and 3), the same polymerization conditions—target DP, solids content, reaction temperature, and time—were applied to a comparative experiment using BA / I2 / V50 / NaI / BNI / Tween80 / FES77 (Table 3, entry 1). Specifically, a mixture of iodine (I2) (0.03 mM), 2,2'-azobis(2-methylpropanediamine) dihydrochloride (V50) (0.06 mM, azo initiator), and 1 mL of water was placed in a Schlenk tube, purged with a continuous argon flow for 5 min, and then heated at 60°C with magnetic stirring for 5–6 hours (depending on the iodine powder size). When the solution becomes colorless and transparent (indicating the completion of the prepolymerization reaction), butyl acrylate (BA) (27.2 mM, monomer), V50 (0.032 mM, azo initiator), and tetrabutylammonium iodide (Bu4N) are added under a continuous argon flow. + I - A mixture of [BA] (0.017 mM, catalyst), sodium iodide (NaI) (0.019 mM, catalyst), Tween 80 (emulsifier), FES77 (emulsifier, the total amount of Tween and FES77 emulsifier (3 / 1, w / w) is [BA]0 / [emulsifier]0 / [water]0 = 45 / 5 / 55 (w / w / w)) and additional water (55 wt.%, the total amount of monomer and reagent mixture is 45 wt.%) was then heated at 60°C with magnetic stirring for 2 h. Conventional emulsion polymerization of BA resulted in a lower monomer conversion of 79% (compared to 91% in Table 2, Entrance 3) and a wide PDI of 4.1 for GPC (compared to 2.5 in Table 2, Entrance 3).

[0201] Table 3. Synthesis of polymer emulsions using I2 / azo and commercial emulsifiers

[0202]

[0203] a. The target degree of polymerization (DP) at 100% monomer conversion, calculated based on [BA]0 / 2[I2]0. b. The theoretical molecular weight (M) calculated based on ([BA]0 / 2[I2]0) × (monomer conversion) × (molecular weight of BA). n value.

[0204] Comparison Example 2:

[0205] Surfactant-free synthesis of diblock polymer emulsions was also performed as a comparative example to demonstrate the advantages of the triblock polymerization technique of the present invention. To better compare with the techniques of our invention (Table 2, entries 1, 2 and 3), the same polymerization conditions of target DP, solids content, reaction temperature and time were applied to comparative experiments using PSSNa as the hydrophilic block and PBA as the hydrophobic block (Table 4, entries 1 and 2).

[0206] Block 1: A mixture of iodine (I₂) (0.03 mM), 2,2'-azobis(2-methylpropanediamine) dihydrochloride (V50) (0.06 mM, azo initiator), and water was placed in a Schlenk tube, purged with a continuous argon flow for 5 min, and then heated at 60°C with magnetic stirring for 5–6 h (depending on the iodine powder size). When the solution became colorless and clear (indicating the completion of the prepolymerization reaction), a mixture of SSNa (0.49 mM, monomer), V50 (0.032 mM, azo initiator), and sodium iodide (NaI) (0.019 mM, catalyst) was placed in a Schlenk tube, purged with a continuous argon flow for 5 min, and then heated at 60°C with magnetic stirring for 60 min. The first block PSSNa–I in water was then successfully prepared for use (monomer conversion >90%). The target degree of polymerization (DP) calculated based on [SSNa]0 / 2[I2]0 at 100% monomer conversion is 8, and the actual DP is 16.

[0207] Block 2: Subsequently, butyl acrylate (BA) (27.2 mM, monomer) and tetrabutylammonium iodide (Bu4N) were added under a continuous argon flow. + I -A mixture of BNI (0.017 mM, catalyst), V50 (0.032 mM, azo initiator), and water (55 wt.%, total monomer and macromolecular initiator amount 45 wt.%) was prepared. The mixture was then purged with a continuous argon flow for 5 min and heated at 60°C with magnetic stirring for 2 h. Comparative emulsion polymerization of BA resulted in a low monomer conversion of 21%, with a PDI of 2.5 for 2 h (phase separation appearance) and a monomer conversion of 82%, with a PDI of 3.0 for 18 h (cured appearance) (compared to the 91% monomer conversion in Table 2, Item 1, with a PDI of 2.5 for 2 h (stable emulsion particle formation)). The slower polymerization rate addresses the limited contact of reactants due to phase separation, while curing addresses the unmeasurable particle structure. The final emulsion had a solids content of 45 wt.%.

[0208] Table 4. One-pot synthesis of diblock polymer emulsions using I2 / azo polymers

[0209] Segment 1:

[0210]

[0211]

[0212] a. The numbers in parentheses are the actual ratios, i.e., the sum of this step and the previous steps. b. The theoretical M calculated based on [M]0, [initiator / macromolecule initiator]0, and monomer conversion. n Value. c. M n and Determined by DMF-GPC calibrated using PMMA standards. d. M n and Determined by THF-GPC calibrated with PMMA standards.

[0213] As shown in item 2 of Table 3, the equivalence ratio of BA to PSSNa–I is 8000 / 16, that is, 500.

Claims

1. A method for preparing a block copolymer, comprising: a) Add at least one olefinically unsaturated hydrophilic monomer and composition Y to a reactor for polymerization; b) After the polymerization in step a), at least one olefinic unsaturated hydrophobic monomer is added to the reactor for polymerization to obtain an amphiphilic diblock copolymer; c) After the polymerization in step b), at least one olefinic unsaturated hydrophobic monomer is added to the reactor for polymerization; The composition Y contains: A) At least one halogen molecule or a haloalkane optionally substituted with a cyano group. B) At least one iodide salt, and C) At least one free radical polymerization initiator, The equivalent ratio of the at least one olefinic unsaturated hydrophobic monomer in step b) to the polymer formed from the at least one olefinic unsaturated hydrophilic monomer in step a) is in the range of 5 to 60.

2. The method according to claim 1, wherein, The halogenated hydrocarbon is selected from organofluorine compounds, organochlorine compounds, organobromine compounds, and organoiodine compounds, which may optionally be substituted with a cyano group; and the halogen molecule is selected from molecular fluorine, molecular chlorine, molecular bromine, and molecular iodine.

3. The method according to any one of claims 1 or 2, wherein, The haloalkane is an alkyl iodine optionally substituted with a cyano group, preferably 2-iodo-2-methylpropionitrile; and the halogen molecule is molecular iodine.

4. The method according to any one of claims 1 to 3, wherein, The iodide salt comprises organic iodide salts and / or water-soluble iodide salts, preferably water-soluble inorganic iodide salts.

5. The method according to claim 4, wherein, The composition Y in step a) comprises at least one water-soluble iodide salt and at least one organic iodide salt; or the composition Y in step a) comprises at least one water-soluble iodide salt, and at least one organic iodide salt is added in step b).

6. The method according to claim 4 or 5, wherein, The organic iodide salt is selected from substituted ammonium iodide and substituted phosphorus iodide, preferably from tetraalkylammonium iodide and tetraalkylphosphonium iodide, wherein the hydrocarbon group is independently a straight-chain or branched C1-C group each time it appears. 20 -alkyl or C6-C 20 -Aryl, preferably the hydrocarbon group is a straight-chain or branched C2-C8-alkyl.

7. The method according to any one of claims 4 to 6, wherein, The water-soluble iodide salt is selected from iodides of alkaline earth metals, alkali metals and ammonium, and is preferably selected from lithium iodide, sodium iodide, potassium iodide, calcium iodide and ammonium iodide.

8. The method according to any one of claims 1 to 7, wherein, The free radical polymerization initiator is an azo polymerization initiator, preferably selected from 2,2'-azobis(2-methylpropionamide) dihydrochloride, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylpropionitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis-2,3-dimethylbutyronitrile, 2,2-azobis-2,3,3-trimethylbutyronitrile, and 2-phenylazobis-2 The free radical polymerization initiator is selected from 2,2'-azobis-2-isopropylbutyronitrile, 2,2'-azobis-(2,4,4-trimethylpentane), and 1,1'-azobis(cyclohexanenitrile), more preferably from 2,2'-azobis(2-methylpropanediamine) dihydrochloride, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylpentyronitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylpentyronitrile).

9. The method according to any one of claims 1 to 7, wherein, The free radical polymerization initiator is a peroxide or reduction-oxidation initiator system. Preferably, the peroxide is selected from tert-butyl hydroperoxide (TBHP), tert-amyl hydroperoxide (TAHP), cumyl hydroperoxide, di-tert-butyl-peroxide, and di-tert-amyl-peroxide. Preferably, the reduction-oxidation initiator system contains a peroxide and a reducing agent.

10. The method according to any one of claims 1 to 9, wherein, The polymerization in steps a), b), and c) is carried out via reversible complexation-mediated polymerization (RCMP).

11. The method according to any one of claims 1 to 10, wherein, The hydrophilic monomer in step a) is selected from monoene-bonded unsaturated hydrophilic monomers, especially monoene-bonded unsaturated hydrophilic monomers containing amide groups; monoene-bonded unsaturated hydrophilic monomers containing at least one acidic group selected from -COOH, -SO3H and -PO3H2 and their salts; and monoene-bonded unsaturated hydrophilic monomers containing hydroxyl and / or ether groups; preferably, the hydrophilic monomer is selected from monoene-bonded unsaturated hydrophilic monomers containing at least one acidic group selected from -COOH, -SO3H and -PO3H2 and their salts, N-methyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, (meth)acrylate C1-C6 hydroxyalkyl ester, allyl alcohol, hydroxyvinyl C1-C6 alkyl ether and poly(ethylene glycol) C1-C6 alkyl ether (meth)acrylate; and more preferably, step a) The hydrophilic monomer is a monoene-bonded unsaturated hydrophilic monomer and its salt containing at least one acidic group selected from -COOH, -SO3H and -PO3H2.

12. The method according to any one of claims 1 to 11, wherein, The hydrophobic monomers in steps b) and c) are each independently selected from conjugated dienes having 4 to 22 carbon atoms, C1-C of (meth)acrylic acid. 20 Alkyl esters, (meth)acrylic acid C3-C 20 Cycloalkyl esters, (meth)acrylic acid C6-C 20 Aryl esters, styrene, styrene mono- or poly-substituted with C1-C5 alkyl groups, vinyl esters of carboxylic acids having up to 20 carbon atoms; more preferably, the hydrophobic monomer is selected from (meth)acrylic acid C1-C5. 20 Alkyl esters, (meth)acrylic acid C3-C 20 Cycloalkyl esters, (meth)acrylic acid C6-C 20 Aryl esters, styrene, and styrene mono- or poly-substituted with C1-C5 alkyl groups.

13. The method according to any one of claims 1 to 12, wherein, The equivalent ratio of the at least one olefinic unsaturated hydrophobic monomer in step b) to the polymer formed from the at least one olefinic unsaturated hydrophilic monomer in step a) is in the range of 8 to 40, preferably 10 to 30, such as 10 to 20.

14. The method according to any one of claims 1 to 13, wherein, The weight ratio of the at least one olefinic unsaturated hydrophobic monomer in step b) to the at least one olefinic unsaturated hydrophobic monomer in step c) is in the range of 1:2 to 1:400, preferably 1:5 to 1:200, and more preferably 1:10 to 1:

100.

15. The method according to any one of claims 1 to 14, wherein, The polymerization in steps a), b), and c) is carried out under stirring.

16. The method according to any one of claims 1 to 15, wherein, In step a), the amount of the at least one olefinic unsaturated hydrophilic monomer is in the range of 0.5 wt% to 30 wt%, preferably 1 wt% to 20 wt%, and more preferably 1.5 wt% to 10 wt%. In step b), the amount of the at least one olefinic unsaturated hydrophobic monomer is in the range of 0.5 wt% to 30 wt%, preferably 1 wt% to 20 wt%, more preferably 1.5 wt% to 10 wt%; and In step c), the amount of the at least one olefinic unsaturated hydrophobic monomer is in the range of 40 wt% to 99 wt%, preferably 60 wt% to 98 wt%, and more preferably 80 wt% to 97 wt%. In each case, it is based on the total weight of these monomers.

17. The method according to any one of claims 1 to 16, wherein, No surfactants are used.

18. The method according to any one of claims 1 to 17, wherein, The polymerization in steps a), b), and c) takes place in water.

19. A block copolymer obtained by the method according to any one of claims 1 to 18.

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