阅读说明：本技术 一种基于Diels-Alder反应的自修复橡胶及其制备方法 (Self-repairing rubber based on Diels-Alder reaction and preparation method thereof ) 是由 刘月涛 延晨政哲 武玉民 高传慧 王传兴 郑学亮 于 2020-04-28 设计创作，主要内容包括：本发明属于橡胶高分子技术领域,涉及一种基于Diels-Alder反应的自修复橡胶的制备方法,首先将含羟基的乙烯类单体用糠醛进行缩醛改性,然后接枝橡胶,最后添加交联剂双马来酰亚胺,制备具有自修复、可回收的橡胶。本发明将Diels-Alder反应引入橡胶,使其具有良好的力学性能、耐热性,并具有高的自修复效率；制备方法简单高效、实用性强,易于推广。(The invention belongs to the technical field of rubber polymers, and relates to a preparation method of self-repairing rubber based on Diels-Alder reaction. According to the invention, Diels-Alder reaction is introduced into rubber, so that the rubber has good mechanical property and heat resistance and high self-repairing efficiency; the preparation method is simple, efficient, high in practicability and easy to popularize.)

1. A preparation method of self-repairing rubber based on Diels-Alder reaction is characterized in that rubber containing furan groups reacts with bismaleimide to form Diels-Alder bonds, and the self-repairing rubber is obtained.

2. The method for preparing the self-repairing rubber based on the Diels-Alder reaction of claim 1, wherein the rubber containing the furan group is formed by grafting a vinyl monomer containing the furan group with rubber.

3. The method for preparing the self-repairing rubber based on the Diels-Alder reaction of claim 2, wherein the rubber is one or more of natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber and nitrile rubber.

4. The method for preparing the self-repairing rubber based on the Diels-Alder reaction of claim 2, wherein the structural unit formula of the rubber is as follows:

wherein, X and Y are natural numbers larger than zero; r₁Is methyl or hydrogen, R₂Is styrene or acrylonitrile.

5. The method for preparing self-repairing rubber based on Diels-Alder reaction of claim 1, wherein the bismaleimide is one or more of N, N '-1, 3-phenylenebismaleimide, 4,4' -bismaleimidodiphenylmethane, 1, 2-bis (maleimide) ethane, 1, 4-bis (maleimide) butane or 1, 6-bis (maleimide) hexane.

6. The method for preparing the Diels-Alder reaction-based self-repairing rubber according to claim 2, wherein the vinyl monomer containing the furan group is obtained by acetalization reaction of a hydroxyl group-containing vinyl monomer and furfural.

7. The method for preparing the Diels-Alder reaction-based self-repairing rubber according to claim 6, wherein the hydroxyl-containing vinyl monomer is one or more of hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate and hydroxypropyl acrylate.

8. The method for preparing the self-repairing rubber based on the Diels-Alder reaction of claim 5, wherein the grafting reaction adopts a thermal initiation or redox initiation system,

or the initiator comprises one or more of hydrogen peroxide, ammonium persulfate, potassium persulfate, benzoyl peroxide tert-butyl ester, methyl ethyl ketone peroxide and cumene hydroperoxide;

or the reducing agent comprises one or more of ferrous ions, sodium sulfite, sodium bisulfite, N, N-dimethylaniline, N, N-diethylaniline, tetraethylenepentamine and mercaptan.

9. A self-healing rubber based on the Diels-Alder reaction prepared by the process of any one of claims 1 to 8.

10. The use of the Diels-Alder reaction based self-healing rubber of claim 9 in the military, aerospace, electronic, biomimetic fields.

Technical Field

The invention belongs to the technical field of rubber polymers, and particularly relates to self-repairing rubber based on Diels-Alder reaction and a preparation method thereof.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

The rubber has a series of physical and chemical properties, particularly excellent rebound resilience, insulativity, water resistance, plasticity and the like, and has precious properties of oil resistance, acid resistance, alkali resistance, heat resistance, cold resistance, pressure resistance, wear resistance and the like after being properly treated, so the rubber has wide application. However, due to the existence of the irreversible cross-linked structure of the natural rubber, the materials are difficult to heal automatically after being locally damaged, and a large amount of waste garbage is generated after the materials are invalid, so that a series of environmental problems and energy waste are brought.

The hot spot of the current research is to introduce a self-repairing mechanism into a rubber material to prepare an intelligent high polymer material with self-diagnosis and self-healing damage characteristics. The reversible chemistry is used for enabling the chemical crosslinking structure damaged after the material is damaged or loses efficacy to be capable of crosslinking again to realize structural recombination, and the reversible chemical material has the obvious advantages that multiple repairs can be realized, and the self-repairing performance can be further accelerated under the condition of external intervention (such as heating or illumination). Currently, the technology for self-healing rubber relies mainly on the addition of microcapsules and the construction of ionic polymers. However, the inventors found that: a natural rubber material which has excellent mechanical properties and can realize self-repair with high repair efficiency is still lacking.

Research discloses a manufacturing method of self-repairing rubber, which comprises the following steps: firstly, the epoxy modifier is utilized to modify a rubber matrix, and an unsaturated transfer agent is prepared by breaking and bonding a hydrogen bond and then adding an auxiliary agent, so that the self-repairing capability of the finally prepared rubber is improved, and the highest self-repairing capability of the prepared rubber is 67%.

Research discloses that the self-repairing elastic prepolymer and a rubber matrix are mixed and compounded, self-repairing long-chain molecules are uniformly distributed in a rubber system, and the self-repairing rubber is obtained by winding from a molecular angle.

However, the above studies have failed to achieve the objectives of both mechanical properties and self-healing efficiency of the product.

Disclosure of Invention

In order to overcome the problems, the invention provides a preparation method of self-repairing rubber based on Diels-Alder reaction. Firstly, an ethylene monomer containing hydroxyl is subjected to acetal modification by furfural, then rubber is grafted, and finally a cross-linking agent bismaleimide is added to prepare the self-repairing recyclable rubber. According to the invention, Diels-Alder reaction is introduced into rubber, so that the rubber has good mechanical property and high self-repairing efficiency; the preparation method is simple, efficient, high in practicability and easy to popularize.

In order to achieve the purpose, the invention adopts the following technical scheme:

the first aspect of the invention provides a preparation method of self-repairing rubber based on Diels-Alder reaction, which comprises the step of reacting rubber containing furan groups with bismaleimide to form Diels-Alder bonds, thus obtaining the self-repairing rubber.

The research of the application finds that: the Diels-Alder bond is introduced into the rubber, so that the rubber has good mechanical property and high self-repairing efficiency.

In a second aspect of the invention, there is provided a self-healing rubber based on the Diels-Alder reaction prepared by any of the above-described methods.

The self-repairing rubber can regulate and control the crosslinking network of the elastomer material and regulate the crosslinking density by adjusting the molar ratio of the furan group to the bismaleimide, so that the self-repairing rubber has good mechanical property, high repairing efficiency and recyclability.

The third aspect of the invention provides the application of the self-repairing rubber based on the Diels-Alder reaction in the fields of military industry, aerospace, electronics and bionics.

The self-repairing rubber has excellent mechanical properties and high repairing efficiency, so that the requirements of the military industry, aerospace, electronics and bionic fields on high temperature, high pressure, flexibility and extensibility can be met, and the self-repairing rubber is expected to be widely applied to military weapons, aerospace equipment and flexible/wearable electronic equipment.

The invention has the beneficial effects that:

(1) compared with the prior art, the invention introduces furan groups into vinyl monomers containing hydroxyl groups through an acetal reaction, and cross-links the furan groups with bismaleimide to prepare the self-repairing rubber material based on the Diels-Alde reaction, and can regulate and control the cross-linking network of the elastomer material and adjust the size of cross-linking density by adjusting the molar ratio of the furan groups to the bismaleimide, so that the elastomer material has good mechanical properties, high repairing efficiency and recyclability.

(2) The method is simple in operation method, low in cost and universal.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.

FIG. 1 is an infrared spectrum of a self-healing elastomer of example 1 of the present invention;

FIG. 2 is a self-healing stress-strain curve of a self-healing elastomer of example 1 of the present invention.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

As described in the background of the invention, the problem of poor repairing performance of the current self-repairing rubber materials is solved. Therefore, the invention provides self-repairing rubber based on a Diels-Alder reaction, which comprises the steps of carrying out acetal modification on a hydroxyl-containing ethylene monomer by furfural to obtain a monomer with a furan group, grafting the furan-group-containing ethylene monomer with rubber, and adding a cross-linking agent bismaleimide to form a Diels-Alder bond so as to prepare self-repairing recyclable rubber;

the method comprises the following specific steps:

the method comprises the following steps: modifying vinyl monomer containing hydroxyl group with furfural to obtain vinyl monomer with furan group;

step two: the main chain contains a furan group and is grafted with rubber, and then cross-linking agent bismaleimide is added to form a Diels-Alder bond, so that the self-repairing recyclable rubber is prepared;

the structural unit general formula of the rubber is as follows:

wherein, X and Y are natural numbers larger than zero; r₁Is methyl or H, R₂Styrene, acrylonitrile, and the like.

The invention also provides a preparation method of the rubber containing furan groups in the main chain, which is obtained by reacting furfural with vinyl monomer acetal containing hydroxyl groups.

In order to realize the self-repairing performance of the rubber, a furan group is introduced into a rubber main chain, and a reversible Diels-Alder bond is formed by the furan group and bismaleimide, so that the high self-repairing performance of the rubber is realized. In addition, a Diels-Alder bond crosslinking network formed on the main chain can further improve the mechanical property of the rubber.

In some examples, the rubber comprises one or more of natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber and nitrile butadiene rubber, so that Diels-Alder bonds are introduced into the rubber, and the rubber has good mechanical properties and high self-repairing efficiency.

In some examples, the hydroxyl-containing vinyl monomer comprises one or more of hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, and hydroxypropyl acrylate, such that the vinyl monomer having a furan group is obtained through acetal of hydroxyl and aldehyde groups.

In some examples, the hydroxyl groups and aldehyde groups are reacted in an acetal, the molar ratio of aldehyde groups to hydroxyl groups being 1: 2 to link two hydrocarbyloxy groups on the same carbon to form an acetal.

In some examples, the acetalization reaction temperature is 50-80 ℃ and the reaction time is 1-8 h, so that the reaction rate and the yield are improved.

In some examples, the grafting reaction may be initiated by one of an initiation system and a thermal or redox initiation system, the initiator may comprise one or more of hydrogen peroxide, ammonium persulfate, potassium persulfate, benzoyl peroxide tert-butyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, and the like, and the reducing agent may comprise one or more of ferrous ions, sodium sulfite, sodium bisulfite, N-dimethylaniline, N-diethylaniline, tetraethylenepentamine, mercaptans, and the like.

In some examples, the solvent is one or more of chloroform, toluene, xylene, cyclohexane and tetrahydrofuran, and can dissolve all reactants simultaneously to facilitate subsequent reaction.

In some examples, the bismaleimide comprises one or more of N, N '-1, 3-phenylenebismaleimide, 4,4' -bismaleimidodiphenylmethane, 1, 2-bis (maleimide) ethane, 1, 4-bis (maleimide) butane, 1, 6-bis (maleimide) hexane.

In some examples, the grafting reaction is at a temperature of 60-90 ℃ for 2-12 hours to increase the reaction rate and product yield.

In some examples, the molar ratio of furan groups to bismaleimide groups is 2-4: 1, so as to adjust the mechanical property.

In some instances, studies have found that common organic synthesis reactions are employed: the aldehyde group reacts with the hydroxyl group, the reaction condition is simple and mild, and the operation is convenient.

The invention also provides self-repairing rubber prepared by any one of the methods based on the Diels-Alder reaction.

The ethylene monomer containing the furan group can be used for preparing a self-repairing rubber material based on Diels-Alde reaction, and has good mechanical property and high repairing efficiency.

The technical solution of the present application will be described below with specific examples.

In the following examples, the rubber is natural rubber, available from: shenzhen Jitian chemical industry Co., Ltd, other raw materials are also commercially available products.