CN114230739B - Linear-nonlinear block polymer and preparation method thereof - Google Patents

Abstract

The invention discloses a linear-nonlinear block polymer and a preparation method thereof, belonging to the field of polymer synthesis. A linear-nonlinear block polymer disclosed by the invention is composed of a linear polymer chain segment and a non-linear structure polymerized by polyvinyl monomers, and is a new topology polymer. The invention also discloses its preparation method. On the basis of the controllable polymerization of polyvinyl monomers, under anaerobic conditions, one-step preparation of linear-non- Linear block polymers. The method has relatively mild reaction conditions, controllable polymer composition, molecular weight and molecular weight distribution, and easy adjustment of polymer topology, which is suitable for large-scale production and application, and has important application value.

Description

A kind of linear-nonlinear block polymer and its preparation method

technical field

The invention belongs to the field of polymer synthesis, and in particular relates to a linear-nonlinear block polymer and a preparation method thereof.

Background technique

Reversible addition-fragmentation chain transfer radical polymerization (RAFT) and atom transfer radical polymerization (ATRP) are widely used in polymerization due to their advantages such as relatively mild polymerization conditions, wide application range of monomers, and easy control of polymer composition and structure. The preparation of things. With the gradual deepening of the research and application of nonlinear topological structures, it is found that nonlinear topological polymers exhibit significantly different properties from linear topological structures. Polymerization of monovinyl monomers containing only one vinyl functional group by RAFT or ATRP often yields only linear polymers. By pre-modifying RAFT reagents, ATRP initiators or free radical initiators on molecules with specific topological structures, and then polymerizing monovinyl monomers through RAFT or ATRP, brush-type, star-type, hyperbranched, and cyclized and other nonlinear topological polymers. In addition, some progress has been made in the synthesis of cyclized and branched polymers based on the regulation of small molecule RAFT chain transfer agents or the polymerization of polyvinyl monomers initiated by small molecule ATRP initiators.

Linear-nonlinear block polymers exhibit completely different properties from linear, brush, star, hyperbranched, cyclized, etc. polymers due to their unique tadpole-like topology, such as hydrodynamic volume, glass Transition temperature, interface properties, etc., so it has great application potential in the fields of biomedicine, coatings, engineering materials, etc. However, none of the above methods can synthesize linear-nonlinear topological polymers in one step. At present, the synthesis of linear-nonlinear block polymers mainly adopts segmental polymerization and splicing through non-covalent bonds. Due to the difficulty and low efficiency of nonlinear structure synthesis, and the synthesis of linear-nonlinear block polymers needs to consider factors such as the polymerization order of nonlinear structures and linear segments and the block combination mode, making linear-nonlinear block polymers Synthesis is extremely challenging.

Contents of the invention

In order to overcome the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a linear-nonlinear block polymer and its preparation method to solve the problem of insufficient preparation methods of the current linear-nonlinear block polymer.

In order to achieve the above object, the present invention adopts the following technical solutions to achieve:

The invention discloses a linear-nonlinear block polymer. The linear-nonlinear block polymer is composed of a linear polymer segment and a non-linear structure polymerized by polyvinyl monomers. Its structural formula is as follows:

In the formula, m=5～20, p=5～100, q=5～100;

R ₁ is *Br or

_R2 is

In the formula, n=10-200.

The invention also discloses a preparation method of the above-mentioned linear-nonlinear block polymer. One preparation method is to use a macromolecular RAFT reagent as a chain transfer, trigger a polyvinyl monomer through an initiator, and perform reversible addition-fragmentation chain transfer Free radical polymerization; another preparation method is to use a macromolecular ATRP initiator to initiate polyvinyl monomers, and use ligands and catalysts to carry out atom transfer free radical polymerization to obtain linear-nonlinear block polymers.

Preferably, the polyvinyl monomer is divinylbenzene, di(meth)acrylate, tri(meth)acrylate, bisphenol A polyoxyethylene ether diacrylate, 1,4-butanediol Diacrylate, diethylene glycol dimethacrylate, tetraethylene glycol diacrylate, or trimethylolpropane triacrylate.

Preferably, the reversible addition-fragmentation chain transfer radical polymerization reaction comprises the following steps:

1) Fully dissolving polyvinyl monomers, macromolecular RAFT reagents and initiators in a solvent to obtain a reaction mixture system;

2) The reaction mixture system is deoxidized, and the polymerization reaction is carried out after the deoxygenation is completed;

3) Purifying the product to obtain a linear-nonlinear block polymer.

Further preferably, in step 1), the molecular weight of the macromolecular RAFT agent is 500-50000Da, which is composed of polyethylene glycol monomethyl ether and 4-cyanovaleric acid dithiobenzoic acid, dithioester, dithio It can be obtained by coupling carbamate, trithiocarbonate or xanthate.

Further preferably, in step 1), the molar ratio of the polyvinyl monomer, the macromolecular RAFT agent and the initiator is (50-1000):1:(0.1-1);

The initiator is azobisisobutyronitrile, 4,4'-azo(4-cyanovaleric acid) or benzoyl peroxide; the solvent is 2-butanone.

Preferably, the atom transfer radical polymerization reaction comprises the following steps:

1) Fully dissolving polyvinyl monomers, macromolecular ATRP initiators, ligands and catalysts in a solvent to obtain a reaction mixture system;

2) The reaction mixture system is deoxidized; after the deoxygenation is completed, the polymerization reaction is carried out;

3) Purifying the product to obtain a linear-nonlinear block polymer.

Further preferably, in step 1), the macromolecular ATRP initiator has a molecular weight of 500-50000 Da and is obtained by coupling polyethylene glycol monomethyl ether with halogenated alkanes.

Further preferably, in step 1), the molar ratio of the polyvinyl monomer, macromolecular ATRP initiator, ligand and catalyst is (50-1000): 1: (0.5-5): (0.05-0.5) ;

The ligand is N,N,N',N",N"-pentamethyl divinyl triamine, the catalyst is CuBr ₂ , and the solvent is dimethyl sulfoxide.

Further preferably, the polymerization reaction temperature of the reversible addition-fragmentation chain transfer radical polymerization and atom transfer radical polymerization is 20°C-80°C.

Compared with the prior art, the present invention has the following beneficial effects:

The invention discloses a linear-nonlinear block polymer, which is composed of a linear polymer segment and a non-linear structure of polyvinyl polymerization. It is a new topology polymer, and the polymer topology is easy to adjust. The polymer contains a large number of unreacted double bonds, which can be modified by various methods such as Michael addition and click chemistry, which can further improve the function of the polymer and expand the application field of the polymer.

The invention also discloses a preparation method of a linear-nonlinear block polymer. A preparation method is to use a macromolecular RAFT reagent as a chain transfer, trigger a polyvinyl monomer through an initiator, and perform reversible addition under anaerobic conditions -fragmented chain transfer radical polymerization, another preparation method is to initiate polyvinyl monomers with macromolecular ATRP initiators, and carry out atom transfer radical polymerization under anaerobic conditions by using ligands and catalysts to obtain linear-non- Linear block polymers. The above-mentioned preparation method disclosed by the present invention opens up a new way for the synthesis of linear-nonlinear topological polymers, enriches the types of topological polymers, and has important enlightenment significance for the chemical synthesis of topological polymers; and the reaction raw materials It is widely and easily available, the reaction conditions are mild, the composition, structure, molecular weight and molecular weight distribution of the polymer are easy to control, the post-treatment of the product is simple, and the polymerization is easy to operate, which is suitable for large-scale production applications.

Description of drawings

Fig. 1 is the GPC spectrogram before and after synthesis of macromolecule RAFT reagent mPEG-CPABD of the present invention;

Fig. 2 is the GPC spectrogram before and after synthesis of macromolecular ATRP initiator mPEG-Br of the present invention;

Fig. 3 is the synthesizing schematic diagram of the linear-nonlinear block polymer in the embodiment 1 of the present invention;

Fig. 4 is the synthesizing schematic diagram of the linear-nonlinear block polymer in the embodiment 2 of the present invention;

Fig. 5 is the ¹ HNMR spectrogram of the linear-nonlinear block polymer in Example 1 of the present invention;

Fig. 6 is the ¹ HNMR spectrogram of the linear-nonlinear block polymer in Example 2 of the present invention;

Fig. 7 is the GPC spectrogram of linear-nonlinear block polymer molecular weight variation during the reaction process of Example 1 of the present invention;

Fig. 8 is the GPC spectrogram of the molecular weight change of the linear-nonlinear block polymer in the reaction process of Example 2 of the present invention;

Fig. 9 is a kinetic fitting curve of the polymerization process of the linear-nonlinear block polymer in Example 1 of the present invention.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

A linear-nonlinear block polymer disclosed by the invention is composed of a linear polymer chain segment and a non-linear structure polymerized by polyvinyl monomers, and is a new topology polymer.

The invention discloses a preparation method of a linear-nonlinear block polymer. A preparation method uses a macromolecular RAFT reagent as a chain transfer, triggers a polyvinyl monomer through an initiator, and performs reversible addition-fragmentation chain transfer Free radical polymerization, another preparation method is to use a macromolecular ATRP initiator to initiate a polyvinyl monomer, and use a ligand and a catalyst to carry out atom transfer free radical polymerization to obtain a linear-nonlinear block polymer.

The construction steps of macromolecule RAFT reagent in the present invention are as follows:

Use commercially available polyethylene glycol monomethyl ether (mPEG) with 4-cyanopentanoic acid dithiobenzoic acid (CPADB), dithioester, dithiocarbamate, trithiocarbonate, or xanthogen Ester coupling synthesis of macromolecular RAFT reagents. First, dissolve mPEG, 4-cyanopentanoic acid dithiobenzoic acid (CPADB) and 4-(dimethylamino)pyridine (DMAP) in dichloromethane (DCM), pass through nitrogen protection, and secondly, the above The system was placed in an ice-bath environment, and a solution of cyclohexylcarbodiimide (DCC) dissolved in DCM was slowly added dropwise, and after the addition was completed, it was returned to room temperature for further stirring for 40 h. Then, the obtained product was filtered, purified by ether precipitation, dialyzed and freeze-dried to obtain the macromolecular RAFT reagent mPEG-CPADB.

The construction steps of macromolecule ATRP initiator among the present invention are as follows:

Macromolecular ATRP initiators were synthesized using commercially available mPEG and halogenated alkanes. First, mPEG, triethylamine (TEA) was dissolved in DCM. 2-Bromoisobutyryl bromide (BIB) dissolved in DCM was slowly added dropwise under ice-bath conditions, and the reaction was continued to stir at room temperature for 24h. After the reaction, it was washed with deionized water to remove water-soluble triethylamine hydrochloride. Next, the organic phase was dried, concentrated, and precipitated twice in glacial ether. Finally, the product was collected and dried in a vacuum oven to obtain the macromolecular ATRP initiator mPEG-Br.

In the present invention, the reversible addition-fragmentation chain transfer radical polymerization reaction comprises the following steps:

1) Polyvinyl monomers, macromolecular RAFT reagents and initiator azobisisobutyronitrile (AIBN) are fully dissolved in 2-butanone to obtain a reaction mixed system; polyvinyl monomers, macromolecular RAFT reagents and The molar ratio of the initiator is (50-1000): 1: (0.1-1);

2) The reaction mixture system is fully deoxygenated by inert gas replacement, and the polymerization reaction is carried out at 40-80°C after deoxygenation;

3) Use gel permeation chromatography (GPC) to monitor the molecular weight of the polymer, and stop the reaction when the molecular weight reaches 1000-50000Da;

4) The product is purified by a precipitation method to obtain a linear-nonlinear block polymer with a molecular weight of 1000-50000Da;

5) Determine the composition, structure, molecular weight and molecular weight distribution of the polymer by hydrogen nuclear magnetic resonance spectroscopy ( ¹ HNMR) and gel permeation chromatography (GPC).

Atom transfer radical polymerization among the present invention, comprises the following steps:

1) Fully dissolve polyvinyl monomer, macromolecular ATRP initiator, ligand N,N,N',N",N"-pentamethyldivinyltriamine and catalyst CuBr ₂ in dimethyl sulfoxide (DMSO) to obtain a reaction mixed system; the molar ratio of polyvinyl monomer, macromolecular ATRP initiator, ligand and catalyst is (50-1000): 1: (0.5-5): (0.05-0.5);

2) The reaction mixture system is fully deoxygenated by inert gas replacement, and the polymerization reaction is carried out at 20-40°C after deoxygenation;

3) Use gel permeation chromatography (GPC) to monitor the molecular weight of the polymer, and stop the reaction when the molecular weight reaches a specific value of 1000-50000Da;

4) Purify the product to obtain a linear-nonlinear block polymer with a molecular weight of 1000-50000Da;

5) Determine the composition, structure, molecular weight and molecular weight distribution of the polymer by hydrogen nuclear magnetic resonance spectroscopy ( ¹ HNMR) and gel permeation chromatography (GPC).

The linear-nonlinear block polymer prepared by the above preparation method is composed of a linear polymer segment and a non-linear structure polymerized by polyvinyl monomers, and its chemical structural formula is as follows:

In the formula, m=5～20, p=5～100, q=5～100; R ₁ structure can be the following two kinds:

1) *Br; 2)

In the formula, the _R2 structure can be the following two types:

1)

2)

In the formula, n=10-200.

Specific examples are as follows:

Example 1

Based on the mechanism of RAFT polymerization: First, fully dissolve divinylbenzene (DVB, 1.3019g, 10mmol) in a reaction flask with 50mL of 2-butanone, then add the macromolecular RAFT reagent mPEG-CPADB (Mw=5000Da, 250mg, 0.05mmol) and initiator (AIBN, 2.73mg, 0.0167mmol) were stirred and mixed. The obtained reaction system was deoxygenated by argon replacement at room temperature to remove dissolved oxygen and air in the bottle, and the deoxygenation time was 30 minutes. After deoxygenation was completed, the reaction was carried out at 80° C., and the molecular weight was monitored by GPC. After 9.5 hours of reaction, the reaction was stopped to quench free radicals. The product was purified by precipitation method, and a linear-nonlinear block polymer with a molecular weight of 20000Da was obtained. The synthesis schematic diagram is shown in Figure 3, and the performance test results are as follows:

Referring to Fig. 1, it is the GPC spectrogram before and after the synthesis of the macromolecular RAFT reagent mPEG-CPABD that the present invention makes, can know from the figure, after the reaction, the peak time obviously shifts to the left, the molecular weight increases, and the molecular weight increment is consistent with the CPABD molecular weight, It was demonstrated that the coupling of mPEG to CPABD was achieved.

Referring to Fig. 7, it is the GPC spectrogram of the molecular weight change of the linear-nonlinear block polymer in the reaction process of Example 1 of the present invention. It can be seen from the figure that the molecular weight increases linearly with the progress of the reaction, and the molecular weight distribution of the polymer does not increase significantly. , that is, no intermolecular cross-linking occurs, and the reaction can achieve good control over the polymerization.

Referring to Fig. 9, it is the kinetic fitting curve of the linear-nonlinear block polymer polymerization process in Example 1 of the present invention. It can be seen from the figure that the reaction time is linearly related to ln([M] ₀ /[M] _t ), where , [M] ₀ is the initial monomer concentration of the reaction, and [M] _t is the monomer concentration at time t corresponding to the reaction time, then the reaction satisfies the first-order kinetic model.

Example 2

Based on ATRP polymerization mechanism: bisphenol A polyoxyethylene ether diacrylate (BEDA, 314.28mg, 2mmol), macromolecular ATRP initiator mPEG-Br

(Mw=2000Da, 40mg, 0.02mmol), ligand N,N,N',N",N"-pentamethyldivinyltriamine (PMDETA, 2.7728mg, 0.016mmol) and catalyst CuBr ₂ (0.8934mg , 0.004mmol) was dissolved in 20mL dimethyl sulfoxide (DMSO) in a 50mL flask, and deoxygenated by bubbling argon for 30min at room temperature. Take a 5cm copper wire and wind it on the magnet, soak it in concentrated hydrochloric acid for 20 minutes, take it out, rinse it repeatedly with acetone and water and wipe it clean, quickly put it into the reaction flask under a nitrogen protective atmosphere, and then perform a short deoxygenation, and then put it in the reaction flask at 25°C Reactions were run and monitored by GPC. After 3 hours of reaction, the reaction was stopped, and the product was purified by precipitation to obtain a linear-nonlinear block polymer with a molecular weight of 15,000 Da. The synthesis schematic diagram is shown in Figure 4, and the performance test results are as follows:

Referring to Fig. 2, it is the GPC spectrogram before and after the synthesis of the macromolecular ATRP initiator mPEG-Br that the present invention makes, as can be seen from the figure, after the reaction, the peak time obviously shifts to the left, the molecular weight increases, and the molecular weight increment is the same as that of 2-bromoiso Butyryl bromide (BIB) substituted some molecular weights, which proved the successful synthesis of mPEG-Br.

Referring to Fig. 8, it is the GPC spectrogram of the molecular weight change of the linear-nonlinear block polymer in the reaction process of Example 2 of the present invention. It can be seen from the figure that the molecular weight increases linearly with the progress of the reaction, and the molecular weight distribution of the polymer does not increase significantly. , that is, no intermolecular cross-linking occurs, and the reaction can achieve good control over the polymerization.

The above content is only to illustrate the technical ideas of the present invention, and cannot limit the protection scope of the present invention. Any changes made on the basis of the technical solutions according to the technical ideas proposed in the present invention shall fall within the scope of the claims of the present invention. within the scope of protection.

Claims (3)

1. A preparation method of a linear-nonlinear block polymer, characterized in that, comprising: 1) First fully dissolve divinylbenzene with 2-butanone, then add macromolecular RAFT reagent and initiator, stir and mix to obtain a reaction system; Wherein, the amount of divinylbenzene is 1.3019g, 10mmol, and the amount of 2-butanone is 50mL; The macromolecular RAFT reagent is mPEG-CPADB, its Mw=5000Da, the dosage is 250mg, 0.05mmol; the initiator is AIBN, the dosage is 2.73mg, 0.0167mmol; 2) Remove the dissolved oxygen in the reaction system and the air in the bottle by argon replacement and deoxygenation method at room temperature, and the replacement deoxygenation time is 30 minutes; 3) After deoxygenation, the reaction was carried out at 80°C, and the molecular weight was monitored by GPC. After 9.5 hours of reaction, the reaction was stopped to quench free radicals, and the product was purified by precipitation to obtain a linear-nonlinear block polymer with a molecular weight of 20,000Da. 2. A preparation method of a linear-nonlinear block polymer, characterized in that, comprising: 1) Bisphenol A polyoxyethylene ether diacrylate, macromolecular ATRP initiator, ligand N,N,N',N'',N''-pentamethyldivinyltriamine and catalyst with dimethyl The base sulfoxide was dissolved in the reaction flask, and deoxygenated by bubbling argon for 30 min at room temperature; Among them, the amount of bisphenol A polyoxyethylene ether diacrylate is 314.28mg, 2mmol; The macromolecular ATRP initiator is mPEG-Br, its Mw=2000Da, the dosage is 40mg, 0.02mmol; The amount of ligand N,N,N',N'',N''-pentamethyldivinyltriamine is 2.7728 mg, 0.016 mmol; The catalyst is CuBr ₂ , the dosage is 0.8934mg, 0.004mmol; The dosage of dimethyl sulfoxide is 20mL; 2) Take a 5cm copper wire and wind it on the magnet, soak it in concentrated hydrochloric acid for 20 minutes, take it out, rinse it repeatedly with acetone and water and wipe it clean, quickly put it into the reaction flask under a nitrogen atmosphere, and perform a short deoxygenation, and then Reactions were performed at 25°C and monitored by GPC; 3) The reaction was stopped after 3 hours of reaction, and the product was purified by precipitation to obtain a linear-nonlinear block polymer with a molecular weight of 15000Da. 3. A linear-nonlinear block polymer, characterized in that it is prepared by the preparation method according to claim 1 or claim 2.