阅读说明：本技术 一种通过可见光引发硫醇-烯点击反应制备的多重响应性树枝化聚合物及其方法 (Multi-responsiveness dendritic polymer prepared by visible light-initiated thiol-ene click reaction and method thereof ) 是由 左晓玲 杨吟野 罗胜耘 于 2019-10-30 设计创作，主要内容包括：本发明属于智能材料与环境材料技术领域,具体的涉及一种通过可见光引发硫醇-烯点击反应制备的多重响应性树枝化聚合物及其方法。本发明以巯基类化合物和丙烯酸酯类化合物为单体,采用硫醇-烯点击化学反应和可见光引发自由基聚合法,成功合成了智能化的多重响应性树枝化聚合物。本发明制备方法的主要优点体现在绿色环保、操作简单、条件温和以及反应高效,不再使用有机酸和碱促进剂,节省了催化剂成本,并且避免了残留金属催化剂的问题。制备合成的多重响应性树枝化聚合物不仅表现出优异的光敏行为,且其光敏行为具有pH和氧化还原依赖性,是一种前景良好的可广泛应用于智能材料与环境材料开发的新型绿色制备技术。(The invention belongs to the technical field of intelligent materials and environmental materials, and particularly relates to a multi-responsiveness dendronized polymer prepared by a thiol-ene click reaction initiated by visible light and a method thereof. The invention successfully synthesizes the intelligent multi-responsiveness dendritic polymer by taking a sulfhydryl compound and an acrylate compound as monomers and adopting a mercaptan-alkene click chemical reaction and a visible light initiated free radical polymerization method. The preparation method has the main advantages of environmental protection, simple operation, mild conditions and high reaction efficiency, does not use organic acid and alkali promoters, saves the cost of the catalyst and avoids the problem of residual metal catalyst. The prepared and synthesized multi-responsive dendronized polymer not only shows excellent photosensitive behavior, but also has pH and redox dependence, and is a novel green preparation technology with good prospect, which can be widely applied to development of intelligent materials and environmental materials.)

1. A multi-responsive dendronized polymer is characterized in that the chemical molecular formula of the polymer is as follows:

(-CH₃CH₂C-(CH₂COO(CH₂)₂S)₃-(CH₂CH(CH₃)COOCH₂)₉-(CCH₂CH₃)₃-)_nwherein n is an integer greater than or equal to 1.

2. A method of preparing the multi-responsive dendrimeric polymer of claim 1 by visible light-initiated thiol-ene click reaction, comprising the steps of:

A. taking a sulfhydryl compound, adding a fluorescent whitening agent in a dark environment, and stirring at 15-25 ℃ to obtain a sulfhydryl mixture;

B. taking an acrylate compound, adding an onium salt photoinitiator in a dark environment, and stirring at 15-25 ℃ to obtain the acrylate compound;

C. and C, mixing and stirring the sulfydryl mixture in the step A and the acrylate compound in the step B at 15-25 ℃ under the irradiation of visible light, and standing to obtain the dendritic polymer.

3. The method for preparing a multi-responsive dendrimeric polymer according to claim 2, wherein the mercapto compound is at least one of pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (mercaptoacetate) and trimethylolpropane tris (3-mercaptopropionate).

4. The method of claim 2, wherein the optical Brightener is at least one of Fluorecent Brightene 9, Fluorecent Brightene 28, Fluorecent Brightene 52, Fluorecent Brightene 71, Fluorecent Brightene 85, Fluorecent Brightene 134, and Fluorecent Brightene 205.

5. The method for preparing a multi-responsive dendrimeric polymer according to claim 2, wherein the acrylate compounds are at least one of isopentyl tetraacrylate, trimethylolpropane triacrylate and trimethylolpropane trimethacrylate.

6. The method of claim 2, wherein the onium photoinitiator is at least one of diphenyliodonium hexafluorophosphate, bis (4-tert-butylphenyl) iodonium hexafluorophosphate, 4 '-dimethyldiphenyliodonium hexafluorophosphate, 4-isobutylphenyl-4' -methylphenyliodiophosphate and triphenylsulfonium hexafluoroantimonate.

7. The method for preparing a multi-responsive dendrimeric polymer by means of visible light-induced thiol-ene click reaction according to any one of claims 2 to 6, wherein the fluorescent whitening agent is used in an amount of 0.2% to 2% of the total weight of the mercapto and acrylate compounds;

the onium salt photoinitiator accounts for 1% -3% of the total weight of the mercapto compound and the acrylate compound;

in the step C, the mass ratio of the mercapto compound to the acrylate compound is (5-6): (5-4).

8. The method for preparing the multi-responsive dendrimeric polymer through visible light-induced thiol-ene click reaction according to any one of claims 2 to 6, wherein in step A, the stirring time is 2-3 h and the stirring speed is 200-300 r/min;

in the step B, stirring time is 2-3 h, and stirring speed is 200-300 r/min;

in the step C, the stirring time is 10-30 min, the stirring speed is 100-200 r/min, and the standing time is 25-35 min.

9. A multi-responsive dendrimeric polymer prepared by a process for preparing a multi-responsive dendrimeric polymer by visible light-initiated thiol-ene click reaction according to any one of claims 2 to 8, characterized in that it is prepared from a mercapto compound, a fluorescent whitening agent, an acrylate compound and an onium salt photoinitiator.

10. The multi-responsive dendronized polymer according to claim 9, wherein the mass ratio of the mercapto compound to the acrylate compound is (5-6): (5-4), the amount of the fluorescent whitening agent accounts for 0.2% -2% of the total weight of the mercapto compound and the acrylate compound, and the onium salt photoinitiator accounts for 1% -3% of the total weight of the mercapto compound and the acrylate compound.

Technical Field

The invention belongs to the technical field of intelligent materials and environmental materials, and particularly relates to a multi-responsiveness dendronized polymer prepared by a thiol-ene click reaction initiated by visible light and a method thereof.

Background

The dendronized polymer has one-dimensional conformation, nano size, rich peripheral groups and various structural characteristics, so that the dendronized polymer is widely applied to the fields of enzyme catalysis, macromolecular carriers, photoelectric materials and the like, and has important application prospects in various national economy fields of national defense, industry, agriculture, medicine, life science, environmental protection and the like. Since the teaching of Takagi Toshinori in 1989 firstly proposed the concept of intelligent material, how to endow the arborization polymer with intelligent performance to induce external stimulation to exchange and transform substances, energy and information with the environment has important research significance in the aspects of sensors, chemical converters, memory element switches, drug controlled release systems, high-efficiency substance separation materials and the like.

The branched polymer mainly comprises the following two synthetic methods: one type is a divergent synthesis method starting from the central core of the dendrimer from inside to outside, the synthesis method is suitable for preparing a large amount of high-generation dendrimers, but the surface functionalization reaction of the prepared compound is incomplete, and the functional diversity and the wide application of a final product are easily influenced; the second type is the stepwise convergent synthesis from the outer layer of the dendrimer from outside to inside, and the compound synthesized by the method has relatively few defects, but the synthesized dendrimer has low generation number. And the mercapto-alkene click chemistry has the reaction characteristics of high reaction rate, no by-product, insensitivity to oxygen, use of a small amount of catalyst or no catalyst and the like, can also overcome the adverse problem that heavy metal Cu ions are remained in a product caused by copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC), and is gradually introduced into the preparation of the dendritic polymer by researchers.

However, the reaction conditions required for the currently used thiol-ene click chemistry initiation are so harsh that it has the problems of high cost, low safety and high degree of harm to human beings.

Fluorecent Brightener 9 is an optical Brightener 9

Fluorescent Brightener 28 is an optical Brightener 28

Fluorecent Brightener 52 is an optical Brightener 52

Fluorecent Brightener 71 is an optical Brightener 71

Fluorecent Brightener 85 is an optical Brightener 85

Fluorecent Brightener 134 is an optical Brightener 134

Fluorecent Brightener 205 is an optical Brightener 205

Disclosure of Invention

The invention aims to solve the technical problems that the reaction conditions required for triggering the thiol-ene click reaction in the prior art are very harsh, so that the safety and the harm degree to human are high, and provides a multi-responsive dendronized polymer prepared by triggering the thiol-ene click reaction through visible light and a method thereof, wherein the reaction conditions are simple, the safety and the harm degree to human are low.

The technical scheme for solving the technical problems is as follows: a multi-responsive dendronized polymer, which has a chemical molecular formula as follows:

(-CH₃CH₂C-(CH₂COO(CH₂)₂S)₃-(CH₂CH(CH₃)COOCH₂)₉-(CCH₂CH₃)₃-)_nwherein n is an integer greater than or equal to 1.

The invention has the beneficial effects that: the multi-responsive dendronized polymer provided by the invention has three properties of light, pH and oxidation reduction. Light is of the photosensitive type, i.e. the product is capable of exhibiting a particular change in physical properties under the action of light or of undergoing a chemical change, such as photocrosslinking, photochromism or photoluminescence, a photoconductivity change, a photocatalytic and photocatalytic change in adhesion to the substrate or a photolytic reaction.

pH means pH-sensitive, i.e., the product contains functional groups, such as-COOH (carboxyl), which are sensitive to hydrogen ions. Under acidic conditions, -COO^-Changing the product into-COOH, reducing the ionization degree of the product, reducing the hydrophilic type and shrinking the molecular chain; under alkaline condition, -COOH group is dissociated continuously, hydrophilic type rises, molecular chain stretches.

Redox refers to redox-sensitive, i.e., the product contains functional groups that are sensitive to the oxidizing/reducing agent, such as sulfur groups. The prepared synthetic multi-responsive dendronized polymer not only has a dendronized structure, but also has the multi-response characteristics of light, pH and oxidation reduction.

The invention also provides a method for preparing the multi-responsive dendronized polymer by using visible light to initiate a thiol-ene click reaction, which comprises the following steps:

A. taking a sulfhydryl compound, adding a fluorescent whitening agent in a dark environment, and stirring at 15-25 ℃ to obtain a sulfhydryl mixture;

B. taking an acrylate compound, adding an onium salt photoinitiator in a dark environment, and stirring at 15-25 ℃ to obtain the acrylate compound;

C. and C, mixing and stirring the sulfydryl mixture in the step A and the acrylate compound in the step B at 15-25 ℃ under the irradiation of visible light, and standing to obtain the dendritic polymer.

The invention has the beneficial effects that: the method initiates the mercaptan-alkene click chemical reaction by visible light irradiation, avoids pollution, realizes green polymerization, is more energy-saving and environment-friendly, is simple and easy to operate, and is beneficial to environmental protection and simple in reaction conditions. And the whole operation process has extremely low harm to people, and solves the technical problems that the existing method has low safety and high harm degree to people due to the harsh reaction conditions required for triggering the mercapto-alkene click chemical reaction. The preparation method has the advantages of simple process, low cost, rapidness, high efficiency, safety, environmental protection, low energy consumption and the like. The prepared and synthesized multi-responsiveness dendronized polymer not only has a dendronized structure, but also has three performances of light, pH and oxidation reduction, and realizes multi-responsiveness. The method is a novel green preparation technology with good prospect, and can be widely applied to development of intelligent materials and environmental materials. The visible light is preferably natural light.

On the basis of the technical scheme, the invention can be further improved as follows.

Further, the mercapto compound is at least one of pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (mercaptoacetate), and trimethylolpropane tris (3-mercaptopropionate).

The beneficial effect of adopting the further scheme is that the sulfhydryl compound can enable the obtained multi-response dendronized polymer to have better quality and multiple choices.

Further, the Fluorescent whitening agent is at least one of Fluorescent Brightener Brighter 9, Fluorescent Brighter 28, Fluorescent Brighter 52, Fluorescent Brighter 71, Fluorescent Brighter 85, Fluorescent Brighter 134, and Fluorescent Brighter 205.

The fluorescent whitening agent has the advantages that the fluorescent whitening agent has multiple determined choices, and the preparation method is more efficient and faster. The above optical brighteners were purchased from Sigma company, usa.

Further, the acrylate compound is at least one of isoprene tetraacrylate, trimethylolpropane triacrylate and trimethylolpropane trimethacrylate.

The beneficial effect of adopting the further scheme is that the determined compound can better facilitate the process. And the multi-response dendritic polymer obtained by the acrylate compounds has better quality.

Further, the onium salt photoinitiator is at least one of diphenyliodonium hexafluorophosphate, bis (4-tert-butylphenyl) iodonium hexafluorophosphate, 4 '-dimethyldiphenyliodonium hexafluorophosphate, 4-isobutylphenyl-4' -methylphenyliodiophosphate and triphenylsulfonium hexafluoroantimonate.

The further scheme has the beneficial effects that the determined compound can better facilitate the process and can obtain the multi-responsiveness dendronized polymer with better quality.

Further, the amount of the fluorescent whitening agent accounts for 0.2-2% of the total weight of the mercapto compound and the acrylate compound;

the onium salt photoinitiator accounts for 1% -3% of the total weight of the mercapto compound and the acrylate compound;

the mass ratio of the mercapto compound to the acrylate compound is (5-6): (5-4).

The method has the advantages that the determined dosage can ensure the stability of the preparation method and improve the quality of the multi-responsiveness dendronized polymer.

Further, in the step A, the stirring time is 2-3 h, and the stirring speed is 200-300 r/min;

in the step B, stirring time is 2-3 h, and stirring speed is 200-300 r/min;

in the step C, the stirring time is 10-30 min, the stirring speed is 100-200 r/min, and the standing time is 25-35 min.

The further scheme has the advantages that the preparation speed of the multi-responsive dendronized polymer is higher, the prepared multi-responsive polymer has better quality, and the prepared multi-responsive dendronized polymer has better light, pH and redox performance stimulation responsiveness.

The invention also provides a multi-responsiveness dendronized polymer prepared by the method for preparing the multi-responsiveness dendronized polymer through the visible light-initiated thiol-ene click reaction, and the multi-responsiveness dendronized polymer is prepared from a mercapto compound, a fluorescent whitening agent, an acrylate compound and an onium salt photoinitiator.

The invention has the beneficial effects that: the obtained multi-responsiveness dendronized polymer has three performances of light, pH and oxidation reduction, and realizes multi-responsiveness.

On the basis of the technical scheme, the invention can be further improved as follows.

Further, the mass ratio of the mercapto compound to the acrylate compound is (5-6): (5-4), the amount of the fluorescent whitening agent accounts for 0.2% -2% of the total weight of the mercapto compound and the acrylate compound, and the onium salt photoinitiator accounts for 1% -3% of the total weight of the mercapto compound and the acrylate compound.

The method has the beneficial effect that the quality of the multi-responsiveness dendronized polymer can be ensured and improved by the determined dosage proportion. The prepared and synthesized multi-responsive dendronized polymer not only shows excellent photosensitive behavior, but also has pH and redox dependence, and is a new material with good prospect and capable of being widely applied to development of intelligent materials and environmental materials.

Drawings

FIG. 1 is a schematic representation of a thiol-ene solution before stirring reaction of example 1 of the present invention;

FIG. 2 is a schematic view of a thiol-ene solution after stirring for 10min according to example 1 of the present invention;

FIG. 3 is a schematic representation of a thiol-ene solid after standing according to example 1 of the present invention;

FIG. 4 is a nuclear magnetic resonance hydrogen spectrum of the multi-responsive dendrimers of the present invention;

FIG. 5 is a graph of mass retention and differential mass loss of a multi-responsive dendrimeric polymer prepared by visible light-induced thiol-ene click reaction according to the present invention;

FIG. 6 is a graph showing the absorbance change of a multi-responsive dendrimers prepared by the thiol-ene click reaction induced by visible light according to the present invention;

FIG. 7 is a graph of normalized decay rate versus time for a multireactive dendrimeric polymer prepared by visible light-induced thiol-ene click reaction and polystyrene at a wavelength of 350 nm.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.