WO2017202091A1 - Block copolymer and preparation method therefor - Google Patents

Abstract

The present invention relates to the field of polymers. Disclosed is a preparation method for a block copolymer. The preparation method specifically comprises: using an azide group-terminated polymer and an (α, β)-unsaturated ester-terminated polymer as raw materials; performing a cycloaddition reaction in a heating condition; and performing product re-precipitation and vacuum drying to obtain a block copolymer. In the present invention, preparation methods for the two polymer raw materials are simple, the reaction is easy to control, a protective gas is not needed, and aftertreatment is convenient. Compared with a conventional method for preparing a block copolymer, the present invention provides a brand new template that can be used for preparing various block copolymers.

Description

Block copolymer and preparation method thereof Technical field

The present invention relates to the field of polymers, and in particular to a method for preparing a block copolymer and a block copolymer prepared by the method.

Background technique

As a widely used material, the design and synthesis of block copolymers has always been one of the important research fields of polymer chemistry. At present, block copolymers have been widely used in fields such as biomaterials, plastics, rubber, composite materials and the like. Moreover, the self-assembly behavior of the block copolymer can form an ordered structure of materials, such as micelles, vesicles, worm-type structures, etc., and has superior performance in the field of drug controlled release.

Currently, synthetic block copolymers have various methods such as atom transfer radical polymerization, ring opening polymerization, reversible addition polymerization, click chemistry, and the like. Millions of polymers with different properties have been synthesized by the composition of these methods. However, these methods require multiple steps of reaction and a variety of different reaction systems. Moreover, these methods also require a variety of different metal catalysts, resulting in wasted resources and environmental damage. At the same time, these methods also require an inert gas protection reaction system.

In summary, we urgently need a simple and convenient method for synthesizing block copolymers.

Summary of the invention

The object of the present invention is to overcome the deficiencies of the prior art and to provide a simple and convenient method for synthesizing a block copolymer in green.

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

A method for preparing a block copolymer, the reaction formula of which is as follows:

The azide group-terminated polymer 1 is reacted with the α,β-unsaturated ester-terminated polymer 2,

Wherein M is polyester, polyolefin, polystyrene, methoxypolyethylene glycol or polyethylene glycol, L is one or more methylene groups, and A is polyester, polyolefin, polystyrene, A Oxyethylene glycol or polyethylene glycol, R is hydrogen, alkyl or phenyl, and the catalyst is DBU.

DBU is 1,8-diazabicyclo[5.4.0]undec-7-ene.

Further, the polyester is polymethyl acrylate, polybutyl acrylate or polycaprolactone.

Further, the polyolefin is polyethylene, polypropylene, polymethylpentene or polybutene.

Further, the R is a methyl group.

Further, the molar ratio of the azide group-terminated polymer 1 to the α,β-unsaturated ester-terminated polymer 2 is 1: 1.1 to 1.4.

Further, the molar ratio of the catalyst to the azide group-terminated polymer 1 is 0.05 to 0.2:1.

Further, the post-treatment of the reaction is: after the end of the reaction, it is cooled to room temperature, and subjected to reprecipitation and vacuum drying to obtain a product.

Further, the temperature of the reaction is 60 to 80 °C.

Further, the reaction time is 30 to 60 hours.

Further, the solvent of the reaction is chloroform.

A block copolymer obtained by the above preparation method.

The invention adopts an azide group-terminated polymer and a polymer terminated with an α,β-unsaturated ester as a raw material, and after undergoing a cycloaddition reaction under heating, the product is subjected to heavy precipitation and vacuum drying to obtain a block. Copolymer. Has the following beneficial effects:

1. The azide group-terminated polymer and the α,β-unsaturated ester-terminated polymer used in the present invention are convenient and easy to prepare, and a large amount of literature is available for reference.

2. The catalyst used in the present invention is DBU, which is an alkali which is widely used, is easily available, and avoids the use of a metal catalyst to protect the environment.

3. The reaction conditions of the invention are simple, only simple heating is required, and no inert gas protection is required, and a yield of 70 to 90% can be achieved.

4. The preparation method of the invention is simple and one-step synthesis; the preparation process is simple and easy to control, and the post-treatment is convenient.

The present invention provides a novel template relative to conventional methods of preparing block copolymers and can be used to prepare various types of block copolymers.

DRAWINGS

Figure 1 is a hydrogen nuclear magnetic spectrum of the copolymer prepared in Example 1;

2 is a gel permeation chromatogram of the copolymer prepared in Example 1.

detailed description

The present invention will be further described below in conjunction with specific embodiments:

Example 1

2 g of azide group-capped polycaprolactone (relative molecular mass 20000, structural formula 3), 0.12 g of α,β-unsaturated ester-terminated methoxypolyethylene glycol (relative molecular mass 1000, structural formula) Compound 4) and 1.5 mg of 1,8-diazabicyclo[5.4.0]undec-7-ene were dissolved in 30 mL of chloroform, and heated under reflux at 80 ° C for 48 h. After the reaction was completed, the reaction mixture was cooled to The solvent was evaporated off at room temperature, and reprecipitated by using tetrahydrofuran/methanol, and the obtained precipitate was collected by filtration, and dried under vacuum at 25 ° C for 24 hours to give a product yield of 85%.

The hydrogen nuclear magnetic spectrum of the product is shown in Figure 1. The product was obtained by hydrogen assignment. The gel permeation chromatogram of the product is shown in Figure 2. The curve a is compound 3, the curve b is the product, and the peak position of the product is relative to the compound. 3 moves to the left, and the retention time decreases, indicating an increase in molecular weight due to an increase in molecular weight after the addition reaction.

Example 2

2 g of azide-terminated polycaprolactone (relative molecular mass 20000, azide group and polycaprolactone linked through a methylene group), 0.24 g of α,β-unsaturated ester-terminated methoxy group Ethylene glycol (relative molecular mass 2000, R is ethyl) and 1.5 mg of 1,8-diazabicyclo [5.4.0]undec-7-ene were dissolved in 30 mL of chloroform and heated to reflux at 80 ° C for 48 h. After completion of the reaction, the reaction mixture was cooled to room temperature, and the solvent was evaporated, and then re-precipitated with tetrahydrofuran/methanol, and the obtained precipitate was collected by filtration, and dried under vacuum at 25 ° C for 24 hours to give a product yield of 88%.

Example 3

0.5 g of azide-terminated polycaprolactone (relative molecular mass 5000, azide group and polycaprolactone linked through two methylene groups), 0.24 g of α,β-unsaturated ester-terminated methoxy group Polyethylene glycol (relative molecular mass 2000, R is propyl) and 1.5 mg of 1,8-diazabicyclo [5.4.0]undec-7-ene dissolved in 30 mL of chloroform and heated to reflux at 80 ° C After 48 h, after completion of the reaction, the reaction mixture was cooled to room temperature, and the solvent was evaporated, and then re-precipitated with tetrahydrofuran/methanol, and the obtained precipitate was collected by filtration and dried under vacuum at 25 ° C for 24 h to give a product yield of 90%.

Example 4

0.6 g of azide-terminated polystyrene (relative molecular mass 6000, azide group attached to polystyrene via three methylene groups), 0.24 g of α,β-unsaturated ester-terminated methoxypolyethylene The diol (relative molecular mass 2000, R is hydrogen) and 1.5 mg of 1,8-diazabicyclo [5.4.0]undec-7-ene are dissolved in 30 mL of chloroform and heated under reflux at 80 ° C for 48 h. After completion, the reaction mixture was cooled to room temperature, and the solvent was evaporated, and then re-precipitated with tetrahydrofuran/methanol, and the obtained precipitate was collected by filtration, and dried under vacuum at 25 ° C for 24 hours to give a product yield of 70%.

Example 5

0.6 g of azide-terminated polystyrene (relative molecular mass 6000, azide group attached to polystyrene via four methylene groups), 0.60 g of α,β-unsaturated ester-capped polycaprolactone ( The relative molecular mass is 5000, R is phenyl) and 1.5 mg of 1,8-diazabicyclo [5.4.0]undec-7-ene is dissolved in 30 mL of chloroform, and heated under reflux at 80 ° C for 48 h. The reaction mixture was cooled to room temperature, and the solvent was evaporated, and then re-precipitated with tetrahydrofuran/methanol, and the obtained precipitate was collected by filtration, and dried under vacuum at 25 ° C for 24 h to give a product, yield 77%.

Example 6

1 mol of azide-terminated polymethyl acrylate (azide is linked to polymethyl acrylate via a methylene group), 1.1 mol of α,β-unsaturated ester-terminated polyethylene glycol (R is methyl) And 0.05 mol of DBU was dissolved in 500 mL of chloroform. After heating at 60 ° C for 60 h, after the reaction was completed, the reaction mixture was cooled to room temperature, and the solvent was evaporated, and then re-precipitated with tetrahydrofuran / methanol, and the obtained precipitate was collected by filtration and dried in vacuo to give a product yield of 79%. .

Example 7

1 mol of azide group-terminated methoxypolyethylene glycol (azide group is bonded to methoxypolyethylene glycol via three methylene groups), 1.4 mol of α,β-unsaturated ester-terminated polyethylene ( R is ethyl) and 0.2 mol of DBU is dissolved in 500 mL of chloroform, and heated under reflux at 80 ° C for 30 h. After the reaction is completed, the reaction mixture is cooled to room temperature, and the solvent is evaporated off, and re-precipitated by tetrahydrofuran / methanol, and collected by filtration. The resulting precipitate was dried in vacuo to give a product (yield: 82%).

Example 8

1 mol of azide group-terminated polymethylpentene (azide group is bonded to polymethylpentene via five methylene groups), 1.2 mol of α,β-unsaturated ester-terminated polybutyl acrylate (R is hydrogen And 0.15 mol of DBU was dissolved in 500 mL of chloroform, and heated under reflux at 70 ° C for 50 h. After the reaction was completed, the reaction mixture was cooled to room temperature, and the solvent was evaporated off, and re-precipitated with tetrahydrofuran / methanol, and the obtained precipitate was collected by filtration. Drying in vacuo gave the product in a yield of 87%.

Example 9

Dissolving 1 mol of azide-terminated polypropylene (azido with polypropylene via eight methylene groups), 1.3 mol of α,β-unsaturated ester-terminated polystyrene (R is hydrogen) and 0.12 mol of DBU The mixture was heated to reflux at 70 ° C for 40 h in 500 mL of chloroform. After the reaction was completed, the reaction mixture was cooled to room temperature, and the solvent was evaporated, and then re-precipitated with tetrahydrofuran/methanol, and the obtained precipitate was collected by filtration and dried in vacuo to give product. The yield is 85%.

Example 10

1 mol of azide group-terminated polyethylene glycol (azido group is linked to polyethylene glycol via five methylene groups), 1.2 mol of α,β-unsaturated ester-terminated polybutene (R is phenyl) And 0.1 mol of DBU was dissolved in 500 mL of chloroform, and heated under reflux at 80 ° C for 48 h. After the reaction was completed, the reaction mixture was cooled to room temperature, and the solvent was evaporated by rotary evaporation, and re-precipitated by tetrahydrofuran / methanol, and the obtained precipitate was collected by filtration. Drying in vacuo gave the product in a yield of 89%.

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. All should be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims (10)

1. A method for preparing a block copolymer, the reaction formula of which is as follows:

   

   The azide group-terminated polymer 1 is reacted with the α,β-unsaturated ester-terminated polymer 2,

   Wherein M is polyester, polyolefin, polystyrene, methoxypolyethylene glycol or polyethylene glycol, L is one or more methylene groups, and A is polyester, polyolefin, polystyrene, A Oxyethylene glycol or polyethylene glycol, R is hydrogen, alkyl or phenyl, and the catalyst is DBU.
2. The preparation method according to claim 1, wherein the polyester is polymethyl acrylate, polybutyl acrylate or polycaprolactone.
3. The production method according to claim 1, wherein the polyolefin is polyethylene, polypropylene, polymethylpentene or polybutene.
4. The method according to claim 1, wherein said R is a methyl group.
5. The method according to claim 1, wherein the molar ratio of the azide-terminated polymer 1 to the α,β-unsaturated ester-terminated polymer 2 is from 1:1.1 to 1.4.
6. The process according to claim 1, wherein the molar ratio of the catalyst to the azide group-terminated polymer 1 is from 0.05 to 0.2:1.
7. The preparation method according to claim 1, wherein the post-treatment of the reaction is: after completion of the reaction, it is cooled to room temperature, and subjected to reprecipitation and vacuum drying to obtain a product.
8. The preparation method according to claim 1, wherein the reaction temperature is 60 to 80 ° C; and the reaction time is 30 to 60 h.
9. The process according to claim 1, wherein the solvent of the reaction is chloroform.
10. A block copolymer obtained by the production method according to any one of claims 1 to 9.

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