阅读说明：本技术 一种紫外光自愈合聚酰胺材料及其制备方法、自愈合方法 (Ultraviolet self-healing polyamide material and preparation method and self-healing method thereof ) 是由 李云涛 李辉 彭博武 赵春霞 曾凯 龙赐杰 于 2019-09-27 设计创作，主要内容包括：本发明公开了一种紫外光自愈合聚酰胺材料,由金属离子与配体聚酰胺通过配位键复合而成,其中,所述聚酰胺中含有偶氮二吡啶结构。聚酰胺中的偶氮二吡啶单元与金属离子的摩尔用量比例为1:0.1-1。聚酰胺的制备方法是：首先,将原料偶氮二吡啶羧酸与二氯亚砜在80℃回流条件下反应合成偶氮二吡啶酰氯；然后,将偶氮二吡啶酰氯与长链二胺在室温条件下,二氯甲烷为溶剂,三乙胺催化条件下合成聚酰胺。将含偶氮二吡啶结构的聚酰胺的二氯甲烷溶液和金属盐的甲醇溶液的混合液,在室温下搅拌24h,然后加热除掉有机溶剂,得到紫外光自愈合聚酰胺材料。本发明的自愈合聚酰胺材料在紫外光照射下,通过可逆的金属配位键,可以实现快速自愈合,愈合效率接近100％。(The invention discloses an ultraviolet self-healing polyamide material which is formed by compounding metal ions and ligand polyamide through coordination bonds, wherein the polyamide contains an azobipyridine structure. The molar ratio of the azobipyridine unit to the metal ion in the polyamide is 1: 0.1-1. The preparation method of the polyamide comprises the following steps: firstly, raw materials of azobipyridine carboxylic acid and thionyl chloride react under the reflux condition of 80 ℃ to synthesize azobipyridine acyl chloride; then, azodipyridyl chloride and long-chain diamine are synthesized into polyamide under the conditions of room temperature, dichloromethane as a solvent and triethylamine as a catalyst. And stirring the mixed solution of the dichloromethane solution of the polyamide containing the azobipyridine structure and the methanol solution of the metal salt at room temperature for 24 hours, and then heating to remove the organic solvent to obtain the ultraviolet self-healing polyamide material. The self-healing polyamide material can realize rapid self-healing through reversible metal coordination bonds under the irradiation of ultraviolet light, and the healing efficiency is close to 100%.)

1. an ultraviolet self-healing polyamide material is compounded by metal ions and ligand polyamide through coordination bonds, and is characterized in that the polyamide contains an azobipyridine structure.

2. The ultraviolet light self-healing polyamide material as claimed in claim 1, wherein the molar ratio of the azobispyridine unit to the metal ion in the polyamide is 1: 0.1-1.

3. The ultraviolet light self-healing polyamide material as claimed in claim 1, wherein the molecular structural formula of the polyamide is as follows:

in the formula, m ranges from 6 to 30, and R is one of the following structures:

n ranges from 5 to 100.

4. the ultraviolet light self-healing polyamide material as claimed in claim 3, wherein the polyamide is synthesized from raw materials of azobipyridyl chloride and long-chain diamine under the conditions of room temperature, dichloromethane as a solvent and triethylamine as a catalyst.

5. The ultraviolet light self-healing polyamide material as claimed in claim 4, wherein the long-chain diamine is one of polysiloxane diamine with molecular weight of 500-.

6. The ultraviolet light self-healing polyamide material as claimed in claim 4, wherein the azobispyridine carboxylic acid chloride is synthesized by reacting azobispyridine carboxylic acid with thionyl chloride under the reflux condition of 80 ℃; the structural formula of the azobipyridine carboxylic acid is as follows:

7. the ultraviolet light self-healing polyamide material as claimed in claim 1, wherein the metal ions are provided by a metal salt, and the metal salt is one or more of zinc dichloride, copper dichloride, ferric chloride, copper sulfate, zinc sulfate, ferric sulfate, zinc trifluoromethanesulfonate, copper trifluoromethanesulfonate, ferric trifluoromethanesulfonate, and terbium chloride.

8. The method for preparing the ultraviolet light self-healing polyamide material as claimed in any one of claims 1 to 7, wherein the mixture of the solution of the polyamide containing the azobispyridine structure in methylene chloride and the solution of the metal salt in methanol is stirred at room temperature for 24 hours, and then the organic solvent is removed by heating to obtain the ultraviolet light self-healing polyamide material.

9. The method for preparing the ultraviolet light self-healing polyamide material as claimed in claim 8, wherein the method for preparing the polyamide comprises the following steps: firstly, raw materials of azobipyridine carboxylic acid and thionyl chloride react under the reflux condition of 80 ℃ to synthesize azobipyridine acyl chloride; then, azodipyridyl chloride and long-chain diamine are synthesized into polyamide under the conditions of room temperature, dichloromethane as a solvent and triethylamine as a catalyst.

10. The self-healing method of the ultraviolet light self-healing polyamide material as claimed in any one of claims 1 to 7, wherein the polyamide material is irradiated with the ultraviolet light with the wavelength of 340-380nm for 1 to 180min and then with the ultraviolet light with the wavelength of 420-460nm for 0 to 30 min.

Technical Field

The invention relates to the technical field of self-repairing materials, in particular to an ultraviolet self-healing polyamide material based on an azopyridine structure, and a preparation method and a self-healing method thereof.

Background

the high molecular polymer composite material is easily affected by factors such as chemical substances, external force, light, heat and the like in the using process, so that microcracks appear in the material. The occurrence and the diffusion of the microcracks degrade the structure and the performance of the material, and influence the use safety and the service life of the material. Therefore, it is undoubtedly an important and practical problem to be able to detect and repair microcracks as soon as possible in view of the potential threat of microcracks to the safety of the material structure. However, the microcracks of the polymer are usually hidden deep inside the polymer, and due to technical limitations, such fine damage as microcracking and the like on many substrates is usually not easily detected. If the damaged part cannot be timely and effectively repaired, the original tiny damage gradually penetrates and is communicated with the damaged part along with the increase of the load, the normal use of the part is finally influenced, the service life of the material is shortened, and larger macrocracks are more likely to be caused, so that major accidents such as sudden failure of the structure are caused. The U.S. military first proposed the concept of self-healing materials in the mid-80's of the 20 th century. The self-healing material can sense the external environment change factors, automatically make adaptive, sensitive and appropriate response, and has the functions of self-diagnosis, self-regulation, self-healing and the like.

Self-healing materials can be classified into external self-healing and intrinsic self-healing according to their energy replenishment modes. The mechanism of the external-aid self-healing material is that a healing agent is added into a matrix in advance, and the healing agent is released when the material is damaged, reacts at the damaged part of the material and fills the defect of the material. The self-healing material has the remarkable characteristic that the self-healing times are limited, so that the application field of the self-healing material is greatly limited. Therefore, the development of intrinsic self-healing materials is greatly promoted. The intrinsic self-healing material can be divided into a dynamic covalent bond and a non-covalent bond, and the dynamic covalent bond type self-healing material can be divided into a Diels-Alder (DA) reaction, coumarin dimerization, a disulfide bond and the like; non-covalent bond type self-healing materials can be classified into hydrogen bonding, pi-pi stacking, ion pairing, coordination bonding, and host-guest interactions. Self-healing systems based on coordination bonds between metals and ligands have many advantages: the metal-ligand composite material has higher mechanical property due to the coordination bond thereof having higher complex constant. By designing the ligand structure and selecting the types and oxidation states of metal ions, the thermodynamic parameters and kinetic parameters of the material can be adjusted in a wide range, and then the self-healing material with adjustable mechanical properties is obtained. In addition, the metal coordination bond is not sensitive to water, so the metal coordination bond has higher application value than a hydrogen bond self-healing material. At present, the types of ligands which can be used for a metal ligand self-healing system are few, and the further development of metal ligand self-healing materials is limited.

In addition, the self-healing material of the metal coordination system generally realizes the self-healing of the material through heating, and the research on the photo-initiated self-healing system is less. Even in the nature published in 2011 by s.j.rowan, self-healing of the ultraviolet initiating material was achieved. The healing mechanism is that the material absorbs ultraviolet light and converts the ultraviolet light into heat through long-time ultraviolet irradiation, so that the temperature of the material reaches 200 ℃, the material is melted, the fluidity of the material is increased to play a role, and the material is actually self-healing triggered by heat.

Disclosure of Invention

the invention aims to provide an ultraviolet self-healing polyamide material based on an azopyridine structure. Under the irradiation of ultraviolet light, the material realizes quick self-healing through reversible metal coordination bonds.

The invention also aims to provide a preparation method of the ultraviolet self-healing polyamide material.

The ultraviolet self-healing polyamide material based on the azopyridine structure is prepared by mixing metal salt and ligand polyamide and compounding metal ions and the ligand polyamide through coordination bonds, and is a composite material. Wherein the polyamide contains an azobipyridine structure. The molar ratio of the azobipyridine unit to the metal ion in the polyamide is 1: 0.1-1.

The molecular structure general formula of the polyamide is as follows:

Wherein R is one of the following structures:

In the formula, m ranges from 6 to 30, and n ranges from 5 to 100.

The metal salt is one or more of zinc dichloride, copper dichloride, ferric chloride, copper sulfate, zinc sulfate, ferric sulfate, zinc trifluoromethanesulfonate, copper trifluoromethanesulfonate, ferric trifluoromethanesulfonate and terbium chloride.

a preparation method of the ultraviolet self-healing polyamide material comprises the following steps:

(1) Preparation of the polyamide: firstly, raw materials of azobipyridine carboxylic acid and thionyl chloride react under the reflux condition of 80 ℃ to synthesize azobipyridine acyl chloride; then, azodipyridyl chloride and long-chain diamine are synthesized into polyamide containing an azo structure under the conditions of room temperature, dichloromethane as a solvent and triethylamine as a catalyst. The molar addition ratio of the azobipyridyl chloride to the long-chain diamine is 1: 1. The long-chain diamine is one of polysiloxane diamine, polyether diamine, polyethylene glycol diamine, polypropylene glycol diamine and polytetramethylene glycol diamine with the molecular weight of 500-5000-. The structural formula of the raw material azobipyridine carboxylic acid is as follows:

(2) And stirring the mixed solution of the dichloromethane solution of the polyamide containing the azobipyridine structure and the methanol solution of the metal salt at room temperature for 24 hours, and then heating to remove the organic solvent to obtain the ultraviolet self-healing polyamide material.

A self-healing method of the ultraviolet light self-healing polyamide material comprises the steps of irradiating the polyamide material with 380nm ultraviolet light with the wavelength of 340-. Under the irradiation of ultraviolet light, the polyamide material can realize quick self-healing through reversible metal coordination bonds, and the healing efficiency is close to 100%.

Compared with the prior art, the invention has the advantages that:

Firstly, an optically active azo structure is introduced into the polyamide material to form a photoresponse metal ligand self-healing system, and the polyamide material can realize rapid self-healing through reversible metal coordination bonds under the irradiation of ultraviolet light, and the healing efficiency is close to 100%. The light can be remotely triggered, the radiation dose can be accurately controlled, and material deformation cannot be caused.

Secondly, the polyamide material provided by the invention has the advantages of simple preparation process steps and good repeatability, and the obtained polyamide material has low healing temperature, can realize rapid self-healing of ultraviolet light and has high healing efficiency.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

FIG. 1 shows a nuclear magnetic resonance hydrogen spectrum of a polyamide prepared in example 1.

FIG. 2 is an infrared spectrum of a polyamide produced in example 1.

FIG. 3 is a graph showing a comparison between before and after breakage of the sample prepared in example 1.

FIG. 4 shows the tensile state in the universal testing machine before and after the healing of the sample of example 1.

FIG. 5, 3:1 stress-strain curves before and after healing of a zinc ion coordinated polyamide material.

FIG. 6 shows UV absorption spectra of polyamide and polyamide before and after coordination with zinc ions.

FIG. 7, 2:1 stress-strain curves before and after healing of a zinc ion coordinated polyamide material.

FIG. 8, 2:1 stress-strain curves before and after healing of iron ion coordinated polyamide materials.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.