CN109575298B - Dendritic polymer and synthesis method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of dendritic polymer, and particularly relates to a dendritic polymer and a synthesis method and application thereof. The invention takes 4- (vinyl phenyl) -1-butylene as a repeating unit to construct a chain segment at the periphery of a polymer; using sec-butyl lithium to initiate VSt polymerization reaction; under the action of Karstedt's catalyst, the double bond and dimethyl chlorosilane produce hydrosilylation reaction to produce high activity grafting site capable of producing coupling reaction with several kinds of active anionic chain to prepare the multicomponent dendritic polymer. In addition, the number of grafting sites can be controlled by regulating the polymerization degree of the PVSt chain segment, and the dendritic polymer with high grafting density can be prepared. The dendritic polymers have wide application prospect in the aspect of reducing the processing viscosity of the polymers. In addition, G4-P2VP is dissolved in trifluoroacetic acid aqueous solution, and pyridine groups in molecules of the G4-P2VP have strong coordination capability, so that the G4-P2VP has wide application prospect in the aspect of polymer micelles.

Description

Dendritic polymer and synthesis method and application thereof

Technical Field

The invention belongs to the technical field of dendritic polymer, and particularly relates to a dendritic polymer and a synthesis method and application thereof.

Background

Dendrimers possess many unique properties, such as: high density, low intrinsic viscosity, large cavities within the molecule, etc. The unique properties endow the polymer with a wide application prospect, for example, the polymer can be used as a drug positioning slow release agent, a polymer processing rheology modifier, a catalyst carrier and the like, so that the synthesis of the dendritic polymer is always concerned.

Since the first report of the synthesis of dendritic-like polyethylene oxides by Yves Gnanou in 1995, several methods for synthesizing dendritic-like polymers have been reported. In the existing method for synthesizing the dendritic polymer, the formation of the grafting points at the tail ends of the polymer molecular chains mostly needs to undergo the processes of protection and deprotection, not only the steps are complex, but also the obtained grafting points have low density, thereby causing the yield of the target polymer to be low. (J.Six, Y.Gnanou.Macromol. Symp.,1995, 95, 137−150; V.Percec, B.Barboiu, C.Grigoras, T. K.Bera.J. Am. Chem. Soc., 2003, 125, 6503−6516;A.Matsuo, T.Watanabe, A.Hirao.Macromolecules, 2004, 37, 6283−6290; C. A.Bell, Z.Jia, J.Kulis, M. J.Monteiro.Macromolecules, 2011, 44, 4814−4827;H.Zhang, J.He, C.Zhang, Z.Ju, J.Li, Y.Yang.Macromolecules, 2012, 45(2), 828−841;G.Polymeropoulos, G.Zapsas, K.Ntetsikas, P.Bilalis, Y. Gnanou, N.Hadjichristidis. Macromolecules2017, 90, 1253-1290) therefore, these methods reported so far are not conducive to the large-scale synthesis of dendrimers. In addition, the activity of the grafting sites selected by a plurality of synthetic methods is often low, which is not beneficial to synthesizing the dendritic polymer with a multi-component graft chain, thereby limiting the application performance of the dendritic polymer and the application prospect thereof in industrial production (H.Zhang, J.Zhu, J.He; F.Qiu, H.Zhang, Y.Yang, H.Lee, T.Chang).Polym. Chem., 2013, 4, 830−839）。

Disclosure of Invention

The invention aims to provide a dendritic polymer with high grafting density and containing a multi-component grafting chain, a rapid synthesis method and application thereof.

The invention provides a method for synthesizing a dendritic polymer with high grafting density and a multi-component graft chain, which is different from the previously reported method for synthesizing the dendritic polymer. The invention selects 4- (vinyl phenyl) -1-butylene (VSt) as a repeating unit to construct a chain segment at the periphery of the polymer. With sec-butyl lithium (sBuLi) to initiate VSt polymerization reaction, during the reaction process, the polymerization reaction of styrene type double bonds in molecules occurs, and the butenyl double bonds are not affected. The double bond is then reacted with dimethylchlorosilane (Me) in the presence of Karstedt's catalyst₂SiHCl) to produce high activity grafting site (silicon-chlorine radical) which can produce coupling reaction with several kinds of active anion chain to produce multi-component dendritic polymer. In addition, the number of grafting sites can be controlled by regulating the polymerization degree of the PVSt chain segment, and the dendritic polymer with high grafting density can be prepared.

The invention provides a method for synthesizing a dendritic polymer, which comprises the following specific steps:

(1) taking Tetrahydrofuran (THF) solution of 4-chloromethyl styrene and allyl magnesium chloride as raw materials to synthesize 4- (vinyl phenyl) -1-butylene, which is marked as VSt;

(2) in a mixed solution of THF and toluene at-50 deg.C to-40 deg.C, using sec-butyl lithium (sBuLi) initiates the continuous polymerization of VSt and styrene (St) to form anionic chains of block copolymers, noted as PVSt-b-PSLi; coupling the active polymer anionic chain with 1, 3, 5-tribromomethylbenzene to generate a star polymer containing three polymer chains, which is marked as G1; under the action of Karstedt's catalyst, the butenyl double bond at the periphery of G1 is reacted with Me₂SiHCl undergoes a hydrosilylation reaction to form a star polymer containing a large number of highly reactive silicon-chlorine groups, which is marked as G1-g-SiCl; coupling reaction of the repeating polymer anionic chains with silicon-chlorine groups, and butenyl double bonds with Me₂The hydrosilylation reaction of SiHCl finally obtains a third generation dendritic polymer which contains a plurality of silicon-chlorine groups at the periphery and is marked as G3-g-SiCl；

（3）N₂Under protection, in THF at-80 deg.C to-70 deg.CsSt polymerization is initiated by BuLi to generate an active polystyrene anion chain, which is marked as PSLi; in THF at-80 deg.C to-70 deg.Cs-BuLi initiating polymerization of α -methylstyrene (α -MeSt) to form an active poly (α -methylstyrene) anion chain, designated as P α MeStLi; four generations of dendritic-like PS (marked as G4-PS) and four generations of PS/P alpha MeSt dendritic copolymers (marked as G4-P alpha MeSt) can be obtained by coupling the two polymer anion chains PSLi and P alpha MeStLi with G3-G-SiCl respectively. In order to improve the reaction efficiency of the silicon-chlorine group, in the coupling reaction process, the using amount of an anion chain is slightly larger than that of the Si-Cl group, and finally, toluene is used as a good solvent, methanol is used as a poor solvent, and the excessive polymer grafting arms are removed by a precipitation grading method;

（4）N₂under protection, the mixture is firstly used in THF at room temperaturesReacting BuLi with 1, 1-Diphenylethylene (DPE) to obtain a product, namely DPELi, reducing the temperature of a reaction system to-80 ℃ to-70 ℃, and then initiating 2-vinylpyridine (2 VP) to polymerize to generate an active anion chain, namely P2VPli, and reacting P2VPli with G3-gSiCl coupling to obtain a four-generation dendritic copolymer with a PS inner core and a P2VP outer layer, which is marked as G4-P2 VP; finally, the excess P2VP was removed by precipitation fractionation using toluene as a good solvent and n-hexane as a poor solvent.

In step (1) of the present invention, preferably, the molar ratio of allyl magnesium chloride to 4-chloromethyl styrene is 1: (0.7-0.9).

In step (2) of the present invention, preferably, in the mixed solution of THF and toluene, the volume ratio of THF to toluene is 1: (1.8-2.2); sec-butyl lithium (sBuLi) in the polymerization of VSt with styrene (St),s-molar ratio of BuLi, VSt and St = 1: (8-10): (80-100); PVSt-b-molar ratio of PSLi to bromomethyl = (1.2-1.5): 1; butenyl double bond and Me₂In the hydrosilylation reaction of SiHCl, Me₂Molar ratio of SiHCl to butenyl double bond>5; in the coupling reaction of the polymer anion chains with the silicon-chlorine groups,the amount of the anion chain is 1.2 to 1.5 times of the amount of the silicon chloride group.

In step (3) of the present invention, preferably,sin the polymerization of St initiated by BuLi,s-molar ratio of BuLi to St of 1: (80-100);sin the reaction of BuLi initiating the polymerization of alpha-methylstyrene (alpha-MeSt) to form the living poly (alpha-methylstyrene) anion chain,s-molar ratio of BuLi to alpha-methylstyrene (alpha-MeSt) of 1: (80-100); during the coupling reaction, the dosage of the anion chain is 1.2 to 1.5 times of the dosage of the silicon chloride group.

In step (4) of the present invention, preferably,s-BuLi in reaction with 1, 1-Diphenylethylene (DPE), s-BuLi in a molar ratio to 1, 1-Diphenylethylene (DPE) of 1: (1.1-1.5); in the process of initiating the polymerization of 2-vinylpyridine (2 VP) to generate the active anion chain,s-molar ratio of BuLi to 2-vinylpyridine (2 VP) of 1: (30-50); p2VPLI and G3-gIn the SiCl coupling reaction, the amount of P2VPli is 1.2-1.5 times of the amount of the silicon chloride groups.

The invention selects a novel compound (VSt) with different active functional groups to construct a grafting site, does not need the step of removing a protecting group to form the grafting site, and utilizes an iterative method to quickly synthesize the dendritic polymer with high grafting density and containing various polymer molecular chains.

The synthesized dendritic polymer (such as G4-PS, G4-P alpha MeSt and G4-P2 VP) has PS as inner core and PS, P alpha MeSt and P2VP as outer layers, and the hydrodynamic radius of polymer molecules in THF solution (theR _h) 47.8 nm, 47.7 nm and 36.1 nm, respectively, and an absolute molecular weight of 1.455X 10⁷ g/mol、1.608×10⁷ g/mol、6.033×10⁶g/mol. The polymer molecules are all spheroids, and in a melt state, the molecules of G4-PS and G4-P alpha MeSt are not entangled, so that the polymer has good processability and wide application prospect in reducing the processing viscosity of the polymer. In addition, G4-P2VP can be dissolved in trifluoroacetic acid aqueous solution, and pyridine groups in molecules of the G4-P2VP have strong coordination capability, so that the G4-P2VP has wide application prospect in the aspect of polymer micelles.

In the present invention, Me is used₂SiHCl needs to be distilled under nitrogen atmosphere in order to remove the additives.

The invention adopts two different methods to react G4-P2VP with acid to generate a product G4-P2VP/H⁺The product was completely soluble in water. The first method comprises the following steps: adding 0.1 mol/L trifluoroacetic acid aqueous solution into a round-bottom flask containing G4-P2VP, carrying out ultrasonic treatment for 1 h, and stirring at room temperature for 24 h; finally, filtration was carried out with an organic filter (filter pore diameter: 800 nm) to obtain a colorless and transparent aqueous polymer solution. The second method comprises the following steps: THF was initially introduced into a round-bottomed flask containing G4-P2VP, and after complete dissolution of the polymer, the appropriate amount of trifluoroacetic acid was added and stirred magnetically for 24 h. Then, the polymer THF solution was added dropwise to ten times the volume of the trifluoroacetic acid aqueous solution under vigorous stirring. THF in the solution can be removed by dialysis using 0.1 mol/L trifluoroacetic acid aqueous solution as dialysate. Finally, filtration was carried out with an organic filter (filter pore diameter: 800 nm) to obtain a colorless transparent polymer solution.

According to the invention, a silicon-chlorine group with high activity is used as a grafting site, and a PS active anion chain, a P alpha MeSt active anion chain and a P2VP anion chain can be subjected to coupling reaction with the silicon-chlorine group, so that various dendritic polymers can be obtained. In addition, the number of grafting points at the molecular chain terminal is determined by the polymerization degree of the PVSt chain segment, and the PVSt chain segment with the polymerization degree of 10 is obtained by adjusting the proportion of the initiator and the monomer, so that the obtained dendritic polymer has high grafting density and is favorable for forming polymer molecules with a compact structure. The dendritic polymers are white powder solid, G4-PS and G4-P alpha MeSt have no chain entanglement between molecules under the melt condition, and G4-P2VP can be in CF₃Water-soluble micelles are formed in the aqueous COOH solution.

The polymers prepared according to the invention are characterized by the following methods:

NMR: AVANCE III HD 400MHz type (Bruker) and a test temperature of 25 ℃.

THF mobile phase gel chromatography: the mobile phase is THF, the flow rate of eluent is 1.0 mL/min, the temperature of the chromatographic column is 35 ℃, and the standard curve of the chromatographic column is calibrated by PS.

DMF mobile phase gel chromatography: the mobile phase was DMF (1.6 g/L) containing LiBr, the eluent flow rate was 1.0 mL/min, the column temperature was 50 ℃ and the column standard curve was calibrated with PMMA.

Rotating the rheometer: model HAAKE MARS III (Thermofeisher Co.), a polymer sample sheet having a diameter of 8 mm and a thickness of 0.7mm was tested in a dynamic frequency sweep mode.

ALV sound and static integrated light scattering instrument: hydrodynamic radius of the sample at 90 ℃ scattering angle with cross-correlation mode (R _h) The test temperature was 25 ℃.

Drawings

FIG. 1 is a scheme for the synthesis of 4- (vinylphenyl) -1-butene (VSt).

FIG. 2 shows p-chloromethylstyrene (a) and VSt (b)¹H NMR spectrum (A), and of VSt¹³C NMR spectrum (B).

FIG. 3 is a schematic diagram of the structure of various kinds of dendrimers.

FIG. 4 shows (A) G4-PS and (C) G4-P

Of MeSt and (E) G4-P2VP¹H NMR spectrum, (B) G4-PS, (D) G4-P

Of MeSt and (F) G4-P2VP¹³C NMR spectrum.

FIG. 5 shows G1, G2, G3, G4-PS and G4-P

GPC results for MeSt (THF as mobile phase).

FIG. 6 shows GPC results (DMF as mobile phase) of G1, G2, G3 and G4-P2 VP.

FIG. 7 shows the results of rheological analysis of polymer (C

Representing angular velocity).

FIG. 8 shows the hydrodynamic radii of G4-P2VP in different solutions (R _h) Distribution curve (PDI stands for particle size distribution).

Detailed Description

Example 1: synthetic VSt

VSt can be formed after coupling of 4-Chloromethylstyrene (CMS) with allylmagnesium chloride. 200 mL of a THF solution of allyl magnesium bromide (1.0 mol/L) was added to a four-necked flask equipped with an isopiestic dropping funnel under an argon atmosphere, followed by 23 mL of CMS (0.16 mol) and 50 mL of THF. After the reaction system was cooled to 0 ℃ with an ice-water mixture, the THF solution of CMS was slowly dropped into the flask, the reaction system was warmed to room temperature, and magnetically stirred under argon for 12 hours. After the reaction was complete, 20 mL of saturated ammonium chloride (NH) was slowly added to the flask₄Cl) solution. Pouring the reaction solution into a separating funnel, extracting the product by using diethyl ether, and using saturated NH₄The Cl solution was washed three times. Finally, VSt and proper CaH are mixed₂Adding into round bottom flask, stirring at room temperature for 12 hr, distilling off with reduced pressure distillation apparatus, collecting intermediate fraction, and storing in desiccator. The yield thereof was found to be 87%.¹H NMR (CDCl₃),

(ppm) 7.36 (2H), 7.19 (2H), 6.70 (1H), 5.88 (1H), 5.75 (1H), 5.23 (1H), 5.05 (2H), 2.73 (2H), 2.41 (2H). Mass spectrometry (GC-MS) results showed m/z (C)₁₂H₁₄) = 158。

Example 2: synthesis of a third-generation dendrimer having silicon-chlorine groups at the periphery (G3-g-SiCl）

In a vacuum system, 100 mL of the solution is usednToluene purified from BuLi and 50 mL ofn-flashing BuLi-purified THF to an anionic reaction flask. Charging dry argon into the reaction bottle until the pressure in the bottle is slightly higher than the atmospheric pressure, adding 2.8 mL of VSt (15.9 mmol) into the bottle by using an injector, cooling the reaction solution to-45 ℃ by using an acetonitrile/liquid nitrogen bath, and adding 1.5 mL of the VSt into the reaction solutions-normal to BuLiThe reaction solution immediately appeared orange-red after dissolving in hexane. Magnetically stirring at-45 deg.C for 30min to obtain active anionic chain PVStLi. 16.8 mL of styrene (146.2 mmol) purified with dibutylmagnesium was added to the reaction solution, and the color of the reaction solution was slightly darker. Magnetic stirring for 1 h at-45 ℃ to obtain active anion chain PVSt-b-PSLi. The reaction solution was cooled to-78 ℃ and a THF solution containing 0.075 g of tribenzyl bromide was slowly added dropwise thereto, followed by stirring for 2 hours, and then the reaction was terminated with anhydrous methanol. Finally, toluene is used as a good solvent, methanol is used as a poor solvent, and excessive PVSt-bPS, giving a three-armed star polymer (G1,M _{n, GPC}: 29.8×10³g/mol, molecular weight distribution: (Đ）：1.18，M _{w, MALLS}: 29.2×10³ g/mol）。

To the flask, under an argon atmosphere, was added 1.2 g G1, 50 mL of toluene, 0.13 mL of Karstedt's catalyst, and 0.75 mL of trimethylchlorosilane. And magnetically stirring for 12 hours at the temperature of 25 ℃ to remove impurities which can react with the silicon-chlorine groups in the reaction liquid. Thereafter, 0.73 mL of freshly distilled Me under reduced pressure was added to the reaction flask₂SiHCl, gradually heating to 60 ℃, and magnetically stirring for 1 day to obtain a dark brown reaction solution. Toluene was distilled off under vacuum. 50 mL of toluene were added to the flask and the toluene was distilled off, again under vacuum, and this step was repeated three times to completely remove Me from the flask₂SiHCl and chlorotrimethylsilane. Finally, 30 mL of toluene was added to the reaction flask to prepare G1-g-a toluene solution of SiCl.

At-45 ℃ to PVSt-bAddition of G1-g-a toluene solution of SiCl, magnetically stirred for 2 h and then quenched with degassed methanol. Methanol is taken as a poor solvent, toluene is taken as a good solvent, and excessive PVSt-bPS, to give a second generation dendrimer (G2,M _{n, GPC}: 128.5×10³ g/mol，Đ: 1.29，M _{w, MALLS}:253.9×10³g/mol). It with Me₂After SiHCl reaction, G2-gSiCl, said polymer being associated with a living anionic chain PVSt-bPSLi reaction to giveThree-generation dendrimers (G3,M _{n, GPC}: 455.4×10³ g/mol，Đ: 1.31，M _{w, MALLS}: 2032×10³g/mol). G3 with Me₂SiHCl reaction to obtain G3-g-SiCl。

Example 3: synthesis of four-generation dendritic polystyrene (G4-PS)

In a vacuum system, the handlen-BuLi-purified THF and dibutylmagnesium-purified St are flashed into a reaction flask and dry argon is introduced into the flask until the gas pressure in the flask is slightly above atmospheric pressure. When the temperature of the reaction system is reduced to-78 ℃, adding the mixture into a reaction bottles-BuLi, the solution immediately appeared orange-red. Magnetically stirring for 1 h at the temperature of minus 78 ℃ to obtain the active anion chain PSLi. A small amount of the reaction solution was taken, and quenched with degassed methanol, and the resulting polymer was used for analysis of the degree of polymerization of the graft arm PS. Adding G3-one to a THF solution of PSLig-a toluene solution of SiCl, gradually warmed to-45 ℃ and magnetically stirred for 2 h, terminating excess PSLi with degassed methanol. Removing excessive grafting arms by precipitation classification method with methanol as poor solvent and toluene as good solvent to obtain white powder G4-PS (M _{n, GPC}: 804.1×10³ g/mol，Đ: 1.32，M _{w, MALLS}: 14550×10³ g/mol）。

Example 4: synthesis of a four-generation dendrimer-like PS/P.alpha.MeSt copolymer (G4-P.alpha.MeSt)

In vacuum systems, the handle is distributedn-BuLi purified THF and trioctylaluminum purified alpha-methylstyrene are flashed into a reaction flask, and dry argon is introduced into the reaction flask until the pressure in the flask is slightly above atmospheric pressure. When the temperature of the reaction system is reduced to-78 ℃, adding the mixture into a reaction bottles-BuLi, the solution immediately turns dark red. Stirring for 1 h at-78 ℃ to obtain the active anion chain P alpha MeStLi. Adding G3-g-a toluene solution of SiCl, gradually increasing the temperature to-45 ℃, stirring for 2 h, and terminating the reaction with degassed methanol. Removing excessive P alpha MeSt by precipitation and fractionation with methanol as poor solvent and toluene as good solvent to obtain white powder G4-P alpha MeSt (M _{n, GPC}: 966.9×10³ g/mol，Đ: 1.36，M _{w, MALLS}: 16080×10³ g/mol）。

Example 5: synthesis of a four-generation dendritic PS/P2VP copolymer

Flash evaporation of 200 mL into the reaction flask under vacuumnTHF (BuLi) after impurity removal, and Ar is charged after the system is returned to room temperature₂Until the air pressure in the bottle is slightly higher than the atmospheric pressure, and proper amount of DPE is added into the reaction bottle. Adding an equimolar amount of DPE to the reaction flasksAfter BuLi, the solution immediately turns black and red, the solution is magnetically stirred for 10 min, the reaction bottle is cooled to-78 ℃, argon is filled again until the air pressure in the bottle is slightly higher than the atmospheric pressure. After the 2VP with the impurities removed from the trioctylaluminum was added into the reaction flask, the solution quickly appeared dark red, and was magnetically stirred for 1 h at-78 ℃. Adding G3-gThe toluene solution of-SiCl was slowly warmed up to-45 ℃ and magnetically stirred for 1 hour, and then the reaction was terminated with degassed methanol. Removing excessive P2VP by precipitation classification with toluene as good solvent and n-hexane as poor solvent to obtain white powder G4-P2VP (M _{n, GPC}: 982.3×10³ g/mol，Đ: 1.39，M _{w, MALLS}: 6033×10³ g/mol）。

Claims (7)

1. A method for synthesizing a dendritic-like copolymer is characterized by comprising the following specific steps:

(1) taking tetrahydrofuran THF solution of 4-chloromethyl styrene and allyl magnesium chloride as raw materials to synthesize 4- (vinyl phenyl) -1-butylene, which is marked as VSt;

(2) using sec-butyl lithium in a mixed solution of THF and toluene at-50 deg.C to-40 deg.Cs-BuLi initiating the continuous polymerization of VSt with styrene St to form the anionic chain of the block copolymer, noted as PVSt-b-PSLi; coupling the block copolymer anionic chain with 1, 3, 5-tribromomethylbenzene to produce a star polymer containing three polymer chains, denoted as G1; under the action of Karstedt's catalyst, the butenyl double bond at the periphery of G1 is reacted with Me₂SiHCl undergoes a hydrosilylation reaction to form a star polymer containing high-activity silicon-chlorine groups, which is marked as G1-g-SiCl; coupling reaction of the repeating block copolymer anionic chains with silicon-chlorine groups, and butenyl double bonds with Me₂The hydrosilylation reaction of SiHCl finally obtains a third generation dendritic copolymer which contains a plurality of silicon-chlorine groups at the periphery and is marked as G3-g-SiCl；

（3）N₂Under protection, in THF at-80 deg.C to-70 deg.CsSt polymerization is initiated by BuLi to generate an active polystyrene anion chain, which is marked as PSLi; at-80^oC to-70^oIn THF of C, withs-BuLi initiating polymerization of α -methylstyrene α -MeSt to form an active poly (α -methylstyrene) anion chain, designated as P α MeStLi; coupling the two polymer anion chains PSLi and P alpha MeStLi with G3-G-SiCl respectively to obtain four-generation dendritic-like PS and four-generation P alpha MeSt dendritic-like copolymers which are marked as G4-PS and G4-P alpha MeSt respectively; finally, toluene is used as a good solvent, methanol is used as a poor solvent, and a precipitation classification method is used for removing redundant polymer grafting arms;

or N₂Under protection, firstly, s-BuLi is reacted with 1, 1-diphenylethylene DPE in THF at room temperature to obtain a product, which is marked as DPELi, the temperature of a reaction system is reduced to-80 ℃ to-70 ℃, then the reaction system is used for initiating 2-vinylpyridine 2VP to polymerize to generate an active anion chain, which is marked as P2VPli, and P2VPli and G3-gCoupling SiCl to obtain a four-generation dendritic copolymer with a PS inner core and a P2VP outer layer, and marking as G4-P2 VP; finally, the excess P2VP was removed by precipitation fractionation using toluene as a good solvent and n-hexane as a poor solvent.

2. The method for synthesizing the dendrite-like copolymer of claim 1, wherein in step (1), the molar ratio of the allyl magnesium chloride to the 4-chloromethyl styrene is 1: (0.7-0.9).

3. The method for synthesizing a dendrimer-like copolymer according to claim 1 or 2, wherein in the step (2), the volume ratio of THF to toluene in the mixed solution of THF and toluene is 1: (1.8-2.2); sec-butyl lithiumsBuLi in the polymerization of VSt with styrene St,s-BuLi, VSt and StIn a molar ratio of 1: (8-10): (80-100); PVSt-b-molar ratio of PSLi to bromomethyl (1.2-1.5): 1; butenyl double bond and Me₂In the hydrosilylation reaction of SiHCl, Me₂Molar ratio of SiHCl to butenyl double bond>5; in the coupling reaction of the block copolymer anion chain and the silicon-chlorine group, the amount of the anion chain is 1.2 to 1.5 times of the amount of the silicon-chlorine group.

4. The method for synthesizing the dendrite-like copolymer of claim 3, wherein in step (3),sin the polymerization of St initiated by BuLi,s-molar ratio of BuLi to St of 1: (80-100);sin the reaction of BuLi initiating alpha-methylstyrene alpha-MeSt to polymerize active poly (alpha-methylstyrene) anion chain,s-molar ratio of BuLi to α -methylstyrene α -MeSt is 1: (80-100); during the coupling reaction, the dosage of the anion chain is 1.2 to 1.5 times of the dosage of the silicon chloride group.

5. The method for synthesizing the dendrimer-like copolymer according to claim 1, 2 or 4, wherein in the step (4), in the reaction of s-BuLi with 1, 1-diphenylethylene DPE, the molar ratio of s-BuLi to DPE is 1: (1.1-1.5); in the process of initiating the polymerization of 2-vinylpyridine 2VP to generate an active anion chain, the molar ratio of s-BuLi to 2-vinylpyridine 2VP is 1: (30-50); p2VPLI and G3-gIn the SiCl coupling reaction, the amount of P2VPli is 1.2-1.5 times of the amount of the silicon chloride groups.

6. A dendrimer-like copolymer obtained by the synthesis method according to any one of claims 1 to 5.

7. The arborescent copolymer of claim 6 reacted with an acid to produce a product designated G4-P2VP/H⁺The product was completely soluble in water.

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