阅读说明：本技术 一种基于联吡啶金属配位自修复材料及其制备方法 (Bipyridine-based metal coordination self-repairing material and preparation method thereof ) 是由 马云 张英杰 佘鹏飞 赵强 刘淑娟 于 2020-12-29 设计创作，主要内容包括：本发明提供了一种基于联吡啶金属配位自修复材料及其制备方法,所述自修复材料采用2,2’-联吡啶-4,4’-二甲酸甲酯为原料,通过水解反应、聚合反应和配位作用得到自修复材料。本发明提供的一种基于联吡啶金属配位自修复材料的制备方法利用金属离子的配位作用,保证材料断开后,在满足合适的温度、湿度条件下可以重新连接,且能够实现较高温度下的自修复。(The invention provides a bipyridine-based metal coordination self-repairing material and a preparation method thereof, wherein the self-repairing material is prepared by taking 2,2 '-bipyridine-4, 4' -methyl diformate as a raw material through hydrolysis reaction, polymerization reaction and coordination. The preparation method of the bipyridyl metal coordination-based self-repairing material provided by the invention utilizes the coordination effect of metal ions to ensure that the material can be reconnected under the conditions of meeting the appropriate temperature and humidity after being disconnected, and can realize self-repairing at higher temperature.)

1. The bipyridine-based metal coordination self-repairing material is characterized by having the following chemical structural formula:

2. a preparation method of a bipyridine-based metal coordination self-repairing material is characterized in that the synthetic route of the preparation method is as follows:

3. a preparation method of a bipyridine-based metal coordination self-repairing material is characterized by comprising the following steps:

firstly, dissolving 2,2 '-dipyridyl-4, 4' -methyl diformate in tetrahydrofuran and a water system, adding potassium hydroxide, reacting and refluxing for 8-18h, concentrating the obtained solution, dissolving in water, and dropwise adding a hydrochloric acid solution to precipitate out to obtain 2,2 '-dipyridyl-4, 4' -dicarboxyl, wherein the structural formula of the 2,2 '-dipyridyl-4, 4' -dicarboxyl is as follows:

reacting the product 2,2 '-bipyridyl-4, 4' -dicarboxyl with thionyl chloride at the temperature of 80 ℃ for refluxing for 8h, adding dichloromethane, triethylamine and PDMS after the reaction is finished and drying the concentrated liquid, reacting for 48h at room temperature after half an hour, and settling with methanol to obtain a jelly, wherein the structural formula of the jelly is as follows:

finally, tetrahydrofuran and water are used as solvent, and PtCl is added₂(DMSO)₂Coordinating to obtain brownA colored gum material, the brown gum material having the formula:

4. the preparation method of the bipyridine-based metal coordination self-repair material as claimed in claim 3, wherein the hydrochloric acid is added dropwise until the pH is 1.

5. The preparation method of the bipyridine-based metal coordination self-repair material according to claim 3, wherein the 2,2 '-bipyridine-4, 4' -dicarboxylic acid methyl ester is dissolved in tetrahydrofuran and a water system, potassium hydroxide is added, and the reaction reflux time is 12 hours.

6. The preparation method of the bipyridyl metal coordination self-repair material based on claim 3, wherein the reaction process of the compound A1 and thionyl chloride is carried out under anhydrous and oxygen-free conditions.

7. The preparation method of the bipyridine-based metal coordination self-repair material as claimed in claim 3, wherein the mass ratio of the dichloromethane to the triethylamine to the PDMS is 100: 4: 25, mixing in advance.

8. The preparation method of the bipyridyl metal coordination-based self-repair material as claimed in claim 3, wherein the dichloromethane, triethylamine and PDMS are added in a mixed manner at 0 ℃ which is ice water.

9. The preparation method of the bipyridyl metal coordination self-repair material based on the claim 3, wherein in the step of obtaining the jelly by settling with methanol, after the step of obtaining the jelly by settling with methanol, the jelly is obtained by washing three times to remove the low molecular weight polymer.

10. The preparation method of the bipyridyl metal coordination self-repair material as claimed in claim 3, wherein tetrahydrofuran and water are used as solvents, and PtCl is added₂(DMSO)₂Complexation to give a brown gum-like material, the PtCl₂(DMSO)₂The temperature of the coordination reaction was 80 ℃.

Technical Field

The invention belongs to the field of self-repairing materials, and particularly relates to a bipyridine-based metal coordination self-repairing material and a preparation method thereof.

Background

The self-repairing material is inspired by the self-healing phenomenon of organisms and can be produced at the same time. After the high polymer material is damaged by mechanical force, macromolecular chain homolytic fracture or heterolytic fracture generally occurs, so that microcracks which are difficult to detect are generated in the material, and larger cracks are generated along with the accumulation of time, so that the material is failed quickly, and therefore, the quick repair of the microcracks is very important for a plurality of high polymer materials applied to important fields. In recent ten years, research documents of various self-repairing polymers appear like bamboo shoots in spring after rain, and the application of the research documents to sensors and electronic skins is widely concerned.

The self-repairing material has wide application prospects in advanced industries such as biomedicine, deep space exploration, weapon manufacturing and the like, but the path to be taken is long, and the performance and the application of the self-repairing material still face huge challenges such as material selection, synthesis and preparation, performance optimization and the like.

The self-repairing materials are classified into external aid type and intrinsic type self-repairing materials.

The externally-applied self-repairing material achieves a repairing effect by means of microcapsules or microvessels stored in the material, and when the material is damaged, a repairing agent stored in the microcapsules or the microvessels flows out to enter a damaged part to bond cracks. The repair agent is limited in supply, so that the materials cannot be repaired for many times, and great obstruction is brought to the use.

The intrinsic self-repairing material achieves a repairing effect by means of reestablishment of a reversible covalent bond or a non-covalent bond in the material, namely, cracks are repaired by means of regeneration of the reversible covalent bond or the non-covalent bond.

Compared with an exogenous self-repairing material, the intrinsic self-repairing material can realize multiple self-repairing through the chemical action of reversible covalent bonds and non-covalent bonds by utilizing the chemical structure characteristics of the material. This brings about an eosin for the application of the repair material.

Compared with covalent bonds, the repair material taking the non-covalent bonds as the mechanism has wider application prospect, because the bond energy of the covalent bonds is higher, the repair is difficult after the fracture, the requirement on the environment is often higher, while the bond energy of the non-covalent bonds is smaller, the requirement on the environment is low, and the self-repair process can be carried out in a proper environment.

The coordination of the metal-ligand (M-L) is one of the metal-ligand (M-L), and the metal-ligand (M-L) has wide adjustable range of thermodynamic and kinetic parameters and good environmental adaptability, and is introduced into a self-repairing system to prepare a material with adjustable mechanical properties, so that the material properties can be greatly improved, and therefore, the metal-ligand (M-L) receives more attention in recent years.

In summary, the most studied is a repair material using a dynamic noncovalent bond as a mechanism. The metal-ligand (M-L) material has the characteristic of good repeatability, so that the metal coordination self-repairing material becomes a key research object of people. The invention also follows the idea that the high reversibility of the metal-ligand (M-L), namely the coordination of bipyridine and metal Pt ions, is utilized to enable the linear PDMS skeleton to form a body-shaped structure in space, thereby improving the stretchability of the material.

At present, however, the preparation of such materials is often based on multiple mechanisms, such as the introduction of polyethylene glycol, etc., to form hydrogel, but these are too complex and have long cycle, and the water content of the materials is also required, which is not suitable for popularization of application.

Disclosure of Invention

The technical problem is as follows: the invention aims to provide a bipyridine-based metal coordination self-repairing material and a preparation method thereof, which utilize the excellent coordination effect of metal platinum ions to improve the tensile property and the repairing property of a material taking PDMS as a framework.

The technical scheme is as follows: the invention provides a bipyridine-based metal coordination self-repairing material, which has the following chemical structural formula:

the invention also provides a preparation method of the bipyridyl metal coordination-based self-repairing material, which comprises the following steps:

firstly, dissolving 2,2 '-dipyridyl-4, 4' -methyl diformate in tetrahydrofuran and a water system, adding potassium hydroxide, reacting and refluxing for 12 hours, concentrating the obtained solution, dissolving in water, dropwise adding a hydrochloric acid solution to precipitate, and obtaining 2,2 '-dipyridyl-4, 4' -dicarboxyl, marked as A1, wherein the A1 has the following structural formula:

the product 2,2 '-bipyridyl-4, 4' -dicarboxyl reacts with thionyl chloride in an anhydrous and oxygen-free environment at 80 ℃ for 8h under reflux, the concentrated liquid is dried after the reaction is finished, then a mixed solution of dichloromethane, triethylamine and PDMS is added at 0 ℃, the mixture reacts for 48h at room temperature after half an hour, and the mixture is settled for a plurality of times by methanol dichloromethane (10:1) to obtain a jelly which is marked as A2, wherein the structural formula of A2 is as follows:

finally, tetrahydrofuran and water were used as solvents, 100mg of PtCl were added₂(DMSO)₂Complexation at 80 ℃ gives a brown gum-like material, labeled A3, with the structural formula A3 as follows: .

(III) the beneficial effects are as follows:

1. the preparation raw material bipyridine adopted in the preparation method is easy to obtain, and the preparation method of bipyridine is simple or can be directly purchased, so that the bipyridine is a common chemical raw material;

2. the preparation method of the bipyridine compound has the advantages of simple synthesis steps, mild conditions, few synthesis steps and no further purification step;

3. the compound prepared by the preparation method can be stored for a long time, has good tolerance to the environment, and can quickly finish self-repairing in a wider temperature range.

Drawings

FIG. 1 is a graph showing the tensile properties of the self-healing material according to an embodiment of the present invention at a tensile rate of 2.5 mm/min;

FIG. 2 is a graph showing the tensile properties of the self-healing material at a tensile rate of 5mm/min according to an embodiment of the present invention;

FIG. 3 is a graph showing the tensile properties of the self-healing material according to the embodiment of the present invention at a tensile rate of 7.5 mm/min;

FIG. 4 is a graph showing the tensile properties of the self-healing material at a tensile rate of 10mm/min according to an embodiment of the present invention;

FIG. 5 shows the repairing performance of the self-repairing material at a temperature of 60 ℃ and a self-repairing time of 0.5h in the embodiment of the present invention;

FIG. 6 shows the repairing performance of the self-repairing material with a temperature of 60 ℃ and a self-repairing time of 45min according to the embodiment of the present invention;

FIG. 7 shows the repairing performance of the self-repairing material at a temperature of 60 ℃ and a self-repairing time of 1 hour in the embodiment of the present invention;

FIG. 8 shows the repairing performance of the self-repairing material at a temperature of 60 ℃ and a self-repairing time of 2 hours according to the embodiment of the present invention;

FIG. 9 is a stress-strain cycle plot of the self-healing material at 50% tensile strain in accordance with an embodiment of the present invention;

FIG. 10 is a stress-strain cycle plot of the self-healing material at a tensile strain of 70% according to an embodiment of the present invention;

FIG. 11 is a stress-strain cycle plot of the self-healing material at 100% tensile strain in accordance with an embodiment of the present invention;

FIG. 12 is an optical photograph of the self-healing material taken from the middle in an embodiment of the present invention;

FIG. 13 is an optical photograph of the self-repairing material when the temperature is 60 ℃ and the self-repairing time is 2 hours in the embodiment of the present invention.

Detailed Description

The invention will be better understood by reference to the following examples. The invention is not limited to what has been described in the detailed description.

Example 1: the bipyridine-based metal coordination self-repairing material has the following chemical structural formula:

example 2: preparation method of bipyridine-based metal coordination self-repairing material

The preparation method comprises the following synthetic route:

the preparation method comprises the following steps:

step 1: dissolving 5.6mmol of 2,2 '-bipyridine-4, 4' -dicarboxylic acid methyl ester in a system of 20mL of tetrahydrofuran and 5mL of water, adding 0.1g of potassium hydroxide, reacting under reflux for 12h, concentrating the obtained solution, dissolving in water, and dropwise adding a hydrochloric acid solution to precipitate the solution, thereby obtaining 2,2 '-bipyridine-4, 4' -dicarboxyl (A1), a characterization of compound A1:

¹H NMR(400MHz,DMSO)δ8.94(dd,J＝10.9,4.9Hz,1H),8.85(s,1H),7.98–7.90(m,1H).

step 2: 50mgA1 was mixed with 8mL of thionyl chloride in N₂And (3) refluxing the mixture at the ambient temperature and 80 ℃ for 8h to react, adding 3mL of dichloromethane, 0.22mL of triethylamine and 1g of PDMS at the temperature of 0 ℃, reacting for 48h at room temperature after half an hour, and washing with methanol to be clean. A gum a2 was obtained.

And step 3: and finally, taking 4mL of tetrahydrofuran and 4mL of water as solvents, and adding 100mg of PtCl2(DMSO)2 for coordination to obtain a brown colloidal substance A3, namely the bipyridine-based metal coordination self-repairing material.

Test example 1: measurement of tensile Properties of materials at different draw rates

As shown in fig. 1-4, the stretching rates are respectively 2.5mm/min, 5mm/min, 7.5mm/min and 10mm/min, the breaking strain of the material is reduced along with the increase of the stretching rate, and the stress in the material can be effectively eliminated at a low stretching rate, so that the stretching performance of the material is improved;

test example 2: measurement of the repair Performance of materials at the same temperature and at different times

As shown in fig. 5-8, the self-repairing time is 0.5h, 45min, 1h and 2h at the temperature of 60 ℃, the tensile property of the material is improved along with the increase of the repairing time, and the bipyridine and the Pt ions are fully coordinated along with the increase of the time;

test example 3: measuring stress-strain cycle curve of material

As shown in fig. 9 to 11, the tensile strain was 50%, 70%, and 100%, respectively, and the residual strain was observed through the hysteresis loop and was successfully dissipated to recover the initial state.

Test example 4: measuring self-healing properties of materials

As shown in fig. 12-13, after the material is damaged, the material is placed in an oven at 60 ℃ for 2 hours for self-repairing, and the material is healed; certainly, the bipyridine-based metal coordination self-repairing material prepared by the invention can realize self-repairing at normal temperature, but the corresponding repairing time can be properly prolonged.