CN110054731B

CN110054731B - Preparation method of reversible acid-base discoloration maleimide copolymer

Info

Publication number: CN110054731B
Application number: CN201910388057.6A
Authority: CN
Inventors: 张书香; 翟丛丛; 赵耀东; 李天宇; 张炉青; 宗传永; 张亚彬; 徐琳
Original assignee: University of Jinan
Current assignee: University of Jinan
Priority date: 2019-05-10
Filing date: 2019-05-10
Publication date: 2021-01-05
Anticipated expiration: 2039-05-10
Also published as: CN110054731A

Abstract

The invention discloses a preparation method of reversible acid-base photochromic maleimide copolymer, belonging to the technical field of polymer synthesis and application. The method comprises the following steps: step 1: putting maleimide (NMIs), diallyldimethylamine (MDAA) and Azobisisobutyronitrile (AIBN) in a certain proportion into a reaction vessel, adding a solvent, stirring, vacuumizing, and reacting for a period of time under the protection of nitrogen; step 2: after the reaction is finished, the reaction product in the step 1 is transferred into a dialysis bag for dialysis, and then centrifugation and vacuum drying are carried out to obtain the polymer containing the maleimide with different functional groups. The acid-base photochromic functional material prepared by the method has excellent reversible cycle stability and better application prospect after analysis.

Description

Preparation method of reversible acid-base discoloration maleimide copolymer

Technical Field

The invention relates to the technical field of polymer synthesis and application, in particular to a preparation method of a reversible acid-base discoloration maleimide copolymer.

Background

The practical application potential of reversible switch functional materials in the fields of data storage, sensors, color displays, architecture and construction, healthcare, memory, etc. has made them increasingly interesting. Since the 80 s in the 20 th century, the development of reversible switching functional materials has made great demands on the switching characteristics sensitive to environmental response and stimulation. Most of these reversible switching functional materials contain an organic component and are reversibly switchable under continuous stimulation. However, some organic moieties may be toxic, change slowly in speed in the solid state, and undergo aging and degradation by continued external stimuli (e.g., ultraviolet radiation). All of these problems greatly limit their practical applications. Although there is significant real-world interest in producing stable reversible functional materials to meet the ever-increasing global demands, there are still many challenges in practical applications, such as stability and cost.

Disclosure of Invention

In view of the above-mentioned deficiencies in the prior art, it is an object of the present invention to provide a method for preparing a reversible acid-base thermochromic maleimide copolymer. The technology of the invention combines the characteristics that the polymer has better stability characteristic, excellent hydrophobic property and the like and the maleimide five-membered ring can greatly improve the thermal stability of the polymer to synthesize a novel maleimide copolymer, and the maleimide copolymer is used for preparing the acid-base discoloration functional material.

In order to solve the technical problems, the invention provides the following technical scheme:

the invention provides a preparation method of reversible acid-base discolored maleimide copolymer, which comprises the following steps:

step 1: putting maleimide, diallyldimethylamine and azobisisobutyronitrile in a certain proportion into a reaction vessel, adding a solvent, stirring, vacuumizing, and reacting for a period of time under the protection of nitrogen;

step 2: after the reaction is finished, the reaction product in the step 1 is transferred into a dialysis bag for dialysis, and then centrifugation and vacuum drying are carried out to obtain the polymer containing the maleimide with different functional groups.

In the step 1, the mole ratio of the maleimide to the diallyldimethylamine to the azobisisobutyronitrile is as follows: 1:1:0.02.

Further, in the step 1, the solvent is DMF, and the using amount of the solvent is 1-30% of the total mass of the monomers.

Further, in the step 1, the reaction condition is 65-80 ℃ and the reaction lasts for 10-20 h.

Further, in step 2, the parameters of the dialysis bag are: 2000 g/mol, dialysis time 10-72 h.

Further, in the step 2, the centrifugation condition is 5000-10000r/min, and the centrifugation is 2-10 min.

Further, in the step 2, drying is carried out for 10-24h under the vacuum drying condition of 30-60 ℃.

The synthesis reaction equation of the maleimide copolymer is as follows:

wherein: r is Cyclohexyl (CH), phenyl (Ph), 4-trifluoromethylphenyl (TFMPh) or 2, 4, 6-trichlorophenyl (TCPh).

The invention has the following beneficial effects:

according to the invention, the copolymer is prepared into a solution with a certain concentration, the solvent is DMF, a colored transparent solution is formed, when acid is added into the liquid, carbonyl oxygen in a polymer structure can be combined with hydrogen protons to form an enol structure, the solution is colorless, when triethylamine is continuously added into the solution, amino protons can be combined with nitrogen elements in a diallyl dimethylamine five-membered ring, and the carbonyl oxygen is subjected to electron transfer to form an enolate structure, so that the color is recovered.

The technology of the invention combines the characteristics that the polymer has better stability characteristic, excellent hydrophobic property and the like and the maleimide five-membered ring can greatly improve the thermal stability of the polymer to synthesize a novel maleimide copolymer, and the maleimide copolymer is used for preparing the acid-base discoloration functional material.

Drawings

FIG. 1 is a Gel Permeation Chromatography (GPC) chart of maleimide-based copolymers prepared in examples 1 to 4 of the present invention;

FIG. 2 is a nuclear magnetic hydrogen spectrum of maleimide-based copolymers prepared in examples 1 to 4 of the present invention;

FIG. 3 is a graph showing stability analysis of the maleimide-based copolymer prepared in example 3 of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages to be solved by the embodiments of the present invention clearer, the following detailed description and the accompanying drawings are given in conjunction with specific embodiments. The invention is in no way limited to these examples. The following description is only a preferred embodiment of the present invention, and is only for the purpose of explaining the present invention, and should not be construed as limiting the scope of the present invention. It should be understood that any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

The reagents used in the following examples are all commercially available products unless otherwise specified.

The invention provides a preparation method of reversible acid-base discoloration maleimide copolymer, which is specifically described as follows.

Example 1

A method of preparing a reversible acid-base thermochromic maleimide copolymer, comprising:

step 1: putting cyclohexyl maleimide, diallyl dimethylamine and azobisisobutyronitrile with a molar ratio of 1:1:0.02 into a reaction vessel, adding DMF solution which is 1% of the total mass of the three monomers, stirring and mixing uniformly, vacuumizing, and reacting for 20 hours at 65 ℃ under the protection of nitrogen;

step 2: after the reaction is finished, transferring the reaction product in the step 1 into a dialysis bag for dialysis, wherein the parameters of the dialysis bag are as follows: 2000 g/mol, and the dialysis time is 10 h; then centrifuging at 10000r/min for 8 min, and vacuum drying at 60 ℃ for 10h to obtain the polymer containing maleimide with different functional groups.

Example 2

step 1: placing phenyl maleimide, diallyl dimethylamine and azobisisobutyronitrile with a molar ratio of 1:1:0.02 into a reaction vessel, adding DMF solution which is 10% of the total mass of the three monomers, stirring and mixing uniformly, vacuumizing, and reacting for 10 hours at 80 ℃ under the protection of nitrogen;

step 2: after the reaction is finished, transferring the reaction product in the step 1 into a dialysis bag for dialysis, wherein the parameters of the dialysis bag are as follows: 2000 g/mol, dialysis time 72 h; then centrifuging at 5000 r/min for 10min, and vacuum drying at 30 ℃ for 24h to obtain the maleimide polymer containing different functional groups.

Example 3

step 1: putting 4-trifluoromethylphenylmaleimide, diallyldimethylamine and azobisisobutyronitrile with the molar ratio of 1:1:0.02 into a reaction vessel, adding DMF solution which is 20 percent of the total mass of the three monomers, stirring and mixing uniformly, vacuumizing, and reacting for 15 hours at 70 ℃ under the protection of nitrogen;

step 2: after the reaction is finished, transferring the reaction product in the step 1 into a dialysis bag for dialysis, wherein the parameters of the dialysis bag are as follows: 2000 g/mol, and the dialysis time is 36 h; then, the mixture is centrifuged at 70000 r/min for 8 min and dried in vacuum at 40 ℃ for 16h to obtain the polymer containing the maleimide with different functional groups.

Example 4

step 1: putting 2, 4, 6-trichlorophenylmaleimide, diallyldimethylamine and azobisisobutyronitrile with the molar ratio of 1:1:0.02 into a reaction vessel, adding DMF solution accounting for 30 percent of the total mass of the three monomers, stirring and mixing uniformly, vacuumizing, and reacting for 18 hours at 75 ℃ under the protection of nitrogen;

step 2: after the reaction is finished, transferring the reaction product in the step 1 into a dialysis bag for dialysis, wherein the parameters of the dialysis bag are as follows: 2000 g/mol, and the dialysis time is 48 h; then, the mixture is centrifuged at 80000 r/min for 5min and dried in vacuum at 50 ℃ for 18h to obtain the polymer containing the maleimide with different functional groups.

Gel Permeation Chromatography (GPC) analysis of the reversible acid-base-photochromic maleimide copolymers prepared in examples 1 to 4 above, is shown in FIG. 1. As can be seen from the figure, a peak appears in all 4 polymers, indicating that the resulting polymer is a substance, free of impurities or other polymers. In addition, the obtained polymer has longer peak time, which indicates that the molecular weight of the polymer is the level of oligomer, and the molecular weight range of the 4 polymers is 1400-2500g/mol and the molecular weight distribution is close to 1.00, which proves that the reversible acid-base discoloration maleimide copolymer is successfully prepared.

And nuclear magnetic detection was performed on the reversible acid-base photochromic maleimide copolymers prepared in examples 1 to 4 above, and the results are shown in FIG. 2. The solvent used was deuterated chloroform, and as can be seen from fig. 2, the chemical shifts at 2.875 ppm and 3.783ppm are absorption peaks for the methyl group bonded to the N element in the MDAA structure, and at 3.25 to 4.32 ppm are absorption peaks for the methylene group bonded to the N element. This demonstrates the presence of MDAA in the polymer. Chemical shifts are absorption peaks of methylene in cyclohexyl at 1.04 to 1.87ppm and 3.85ppm, and chemical shifts of phenyl, trifluoromethylphenyl and trichlorophenyl are shown in figure 2h, i, j and are located at 6.86 to 7.98 ppm. Further proving that the invention successfully prepares the reversible acid-base discoloration maleimide copolymer.

The cyclic stability of the reversible acid-base photochromic maleimide copolymer prepared in example 4 above was examined, and the results are shown in FIG. 3. FIG. 3 shows the UV-visible spectrum after ten cycles, and it can be seen that the absorbance of the polymer is not reduced after 10 cycles, indicating that the polymer has better stability.

In conclusion, the novel maleimide copolymer prepared by the invention has excellent reversible cycle stability and better application prospect.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for preparing reversible acid-base photochromic maleimide copolymer, which is characterized by comprising the following steps:

step 1: putting maleimide (NMIs), diallyldimethylamine (MDAA) and Azobisisobutyronitrile (AIBN) in a molar ratio of 1:1:0.02 into a reaction vessel, adding a solvent, stirring, vacuumizing, and reacting for a period of time under the protection of nitrogen;

2. The method for preparing reversible acid-base electrochromic maleimide copolymer according to claim 1, wherein in step 1, the solvent is DMF, and the amount is 1-30% of the total mass of the monomers.

3. The method for preparing reversible acid-base thermochromic maleimide copolymers according to claim 2, wherein in step 1, the reaction conditions are 65-80 ℃ and the reaction time is 10-20 hours.

4. The method for preparing reversible acid-base electrochromic maleimide copolymer according to claim 1, wherein in said step 2, parameters of dialysis bag: 2000-4000g/mol, and the dialysis time is 10-72 h.

5. The method for preparing reversible acid-base photochromic maleimide copolymer according to claim 4, wherein the centrifugation conditions of 5000-10000r/min and 2-10min are employed in the step 2.

6. The method for preparing reversible acid-base thermochromic maleimide copolymers according to claim 5, wherein in step 2, drying is performed under vacuum drying conditions of 30-60 ℃ for 10-24 hours.