阅读说明：本技术 基于咪唑二腈反应性基团的热固性树脂及其制备方法 (Thermosetting resin based on imidazole dinitrile reactive groups and preparation method thereof ) 是由 杨刚 胡江淮 曾科 谭伟 梁博 廖沈军 周涛 陈梦豪 刘耀 于 2019-10-15 设计创作，主要内容包括：本发明公开了一种基于咪唑二腈反应性基团的热固性树脂及其制备方法,所述热固性树脂由含有咪唑二腈的化合物加热固化形成,或者由含有咪唑二腈的化合物和固化剂的共混物加热固化形成,所述含有咪唑二腈的化合物与固化剂的质量比为10：(0.7～1.0)。所述热固性树脂的制备方法是在氮气氛围下,将含有咪唑二腈的化合物,或将含有咪唑二腈的化合物和固化剂的共混物进行固化。本发明所制备的热固性树脂具有优异热稳定性、热氧稳定性和结构可修饰性,是一种具有广泛应用价值的新型材料。(The invention discloses a thermosetting resin based on imidazole dinitrile reactive groups and a preparation method thereof, wherein the thermosetting resin is formed by heating and curing a compound containing imidazole dinitrile or a blend of the compound containing imidazole dinitrile and a curing agent, and the mass ratio of the compound containing imidazole dinitrile to the curing agent is 10: (0.7-1.0). The thermosetting resin is prepared by curing a compound containing imidazole dinitrile, or a blend of a compound containing imidazole dinitrile and a curing agent, in a nitrogen atmosphere. The thermosetting resin prepared by the invention has excellent thermal stability, thermo-oxidative stability and structure modifiability, and is a novel material with wide application value.)

1. A thermosetting resin based on an imidazole dinitrile reactive group, characterized by being formed by heat curing of an imidazole dinitrile-containing compound or by heat curing of a blend of an imidazole dinitrile-containing compound and a curing agent, the mass ratio of the imidazole dinitrile-containing compound to the curing agent being 10: (0.7-1.0).

2. The thermosetting resin based on imidazole dinitrile-reactive groups according to claim 1, wherein the imidazole dinitrile-containing compound is one of the following structural formulae:

wherein the content of the first and second substances,

3. thermosetting resin based on imidazole dinitrile-reactive groups according to claim 1 or 2, characterized in that the curing agent is a lewis acid/lewis base, methylene/methine curing group containing compound.

4. Thermosetting resin based on imidazole dinitrile-reactive groups according to claim 3, characterized in that the Lewis acid/Lewis base is an aromatic amino compound, phenolic hydroxyl compound or metal salt with curing function and the compound containing methylene/methine curing groups is 2,2' - (oxybis (4, 1-phenylene)) bis (3 α,4, 7,7a tetrahydro-1H-isoindole-1, 3(2H) -dione).

5. A method for preparing thermosetting resin based on reactive groups of imidazole dinitrile, characterized in that under nitrogen atmosphere, the compound containing imidazole dinitrile is cured according to the following temperature and time in sequence:

keeping the temperature for 0-10 hours at the temperature T of more than or equal to 150 and less than or equal to 190 ℃,

keeping the temperature for 0-10 hours at the temperature of T more than or equal to 200 and less than or equal to 210 ℃,

keeping the temperature for 0-10 hours at the temperature of more than or equal to 230 and less than or equal to 250 ℃,

t is more than or equal to 290 and less than or equal to 300 ℃, the temperature is kept for 0.5 to 10 hours,

the temperature T is not less than 150 and not more than 190 ℃, the temperature T is not less than 200 and not more than 210 ℃, and the heat preservation time is not more than 230 and not more than 250 ℃ is not 0 at the same time;

or curing the compound containing the imidazole dinitrile at the following temperature and time in sequence:

keeping the temperature for 0-10 hours at the temperature T of more than or equal to 150 and less than or equal to 190 ℃,

keeping the temperature for 0-10 hours at the temperature of T more than or equal to 200 and less than or equal to 210 ℃,

keeping the temperature for 0-10 hours at the temperature of more than or equal to 230 and less than or equal to 250 ℃,

t is more than or equal to 290 and less than or equal to 300 ℃, the temperature is kept for 0-10 h,

keeping the temperature of T more than or equal to 350 and less than or equal to 380 ℃ for 0.5-10 h;

the temperature T is not less than 150 and not more than 190 ℃, the temperature T is not less than 200 and not more than 210 ℃, and the heat preservation time is not more than 230 and not more than 250 ℃ is not 0 at the same time;

after the curing was completed, the resultant product was furnace-cooled to room temperature.

6. A process for the preparation of thermosetting resins based on imidazole dinitrile reactive groups, characterized in that it comprises the following steps:

(1) mixing a compound containing imidazole dinitrile and a curing agent according to the mass ratio of 10: (0.7-1.0) blending, and uniformly blending a compound containing imidazole dinitrile and a curing agent to obtain a blend;

(2) the resulting blend was cured under nitrogen atmosphere at the following temperatures and times in order:

keeping the temperature for 0-10 hours at the temperature T of more than or equal to 150 and less than or equal to 190 ℃,

keeping the temperature for 0-10 hours at the temperature of T more than or equal to 200 and less than or equal to 210 ℃,

keeping the temperature for 0-10 hours at the temperature of more than or equal to 230 and less than or equal to 250 ℃,

t is more than or equal to 290 and less than or equal to 300 ℃, the temperature is kept for 0.5 to 10 hours,

the temperature T is not less than 150 and not more than 190 ℃, the temperature T is not less than 200 and not more than 210 ℃, and the heat preservation time is not more than 230 and not more than 250 ℃ is not 0 at the same time;

or the obtained blend is cured according to the following temperature and time in sequence:

keeping the temperature for 0-10 hours at the temperature T of more than or equal to 150 and less than or equal to 190 ℃,

keeping the temperature for 0-10 hours at the temperature of T more than or equal to 200 and less than or equal to 210 ℃,

keeping the temperature for 0-10 hours at the temperature of more than or equal to 230 and less than or equal to 250 ℃,

t is more than or equal to 290 and less than or equal to 300 ℃, the temperature is kept for 0-10 h,

keeping the temperature of T more than or equal to 350 and less than or equal to 380 ℃ for 0.5-10 h;

the temperature T is not less than 150 and not more than 190 ℃, the temperature T is not less than 200 and not more than 210 ℃, and the heat preservation time is not more than 230 and not more than 250 ℃ is not 0 at the same time;

after the curing was completed, the resultant product was furnace-cooled to room temperature.

7. The method for preparing thermosetting resin based on imidazole dinitrile-reactive group according to claim 5 or 6, characterized in that the compound containing imidazole dinitrile is one of the following structural formulae:

wherein the content of the first and second substances,

8. the process for the preparation of thermosetting resins based on imidazole dinitrile-reactive groups according to claim 6, characterized in that the curing agent is a Lewis acid/Lewis base, methylene/methine curing group containing compound.

9. The method for preparing thermosetting resin based on imidazole dinitrile-reactive group according to claim 6 or 8, wherein in step (1), the imidazole dinitrile-containing compound and the curing agent are blended in such a manner that: dissolving a compound containing imidazole dinitrile and a curing agent in a solvent for mixing, and then spin-drying the obtained mixed solution; the solvent is tetrahydrofuran or acetone.

10. The method for preparing thermosetting resin based on imidazole dinitrile-reactive group according to claim 6 or 8, wherein in step (1), the imidazole dinitrile-containing compound and the curing agent are blended in such a manner that: the imidazole dinitrile-containing compound and the curing agent are mixed by grinding.

Technical Field

The invention belongs to the technical field of high-temperature-resistant resin materials, and particularly relates to thermosetting resin taking imidazole dinitrile as a reactive group and a preparation method thereof.

Background

Along with the rapid development of the high-tech fields of aerospace, marine ships, microelectronics and the like, higher requirements are also put forward on the polymer with high-temperature resistance. Thermosetting high-performance resin has the advantages of high temperature resistance, light weight, corrosion resistance and the like, so the thermosetting high-performance resin always belongs to the leading field of high-performance polymer development by virtue of excellent comprehensive performance.

High performance thermosetting resins having different thermosetting grades have been developed in succession, including benzoxazine resins, bismaleimide resins, arylacetylene resins, phthalonitrile resins, and the like. The phthalonitrile resin taking the nitrile group as the reaction group has wide application prospect in the fields of aerospace, marine ships and the like by virtue of excellent heat resistance, thermal mechanical property, flame retardant property and the like. However, since phthalonitrile resins are based mainly on nucleophilic substitution reactions of 4-nitrophthalonitrile with hydroxyl groups and the like, they have the following disadvantages: (1) because the nucleophilic substitution rapid reaction temperature is about 250 ℃ generally, and the subsequent curing temperature is above 300 ℃, the composite modification of phthalonitrile and other resins is hindered; (2) because the nucleophilic substitution reaction is mainly based on 4-nitrophthalonitrile and hydroxyl, etc., the molecular design and the structural modification are not flexible enough.

Therefore, the development of a high-performance thermosetting resin which is comparable to the thermosetting property of the phthalonitrile resin and can improve the defects of the phthalonitrile resin such as high curing temperature, poor decoration and the like has very important significance and great commercial prospect for the development of high-performance polymers.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a thermosetting resin based on an imidazole dinitrile reactive group and a preparation method thereof, and the prepared thermosetting resin has lower curing temperature, excellent thermal stability and thermal-oxygen stability and good structure modification property.

The thermosetting resin based on the imidazole dinitrile reactive group is formed by heating and curing a compound containing the imidazole dinitrile or a blend of the compound containing the imidazole dinitrile and a curing agent, wherein the mass ratio of the compound containing the imidazole dinitrile to the curing agent is 10: (0.7-1.0).

The thermosetting resin based on the imidazole dinitrile reactive group, wherein the compound containing the imidazole dinitrile is one of the following structural formulas:

wherein the content of the first and second substances,

the above-mentioned imidazole dinitrile-containing compound has 4, 5-dicyanoimidazole as a reactive group, and can be cured (or accelerated) by a Lewis acid/Lewis base such as an aromatic amino group, a phenolic hydroxyl group or a metal salt, and a curing group such as a methylene group/methine group, thereby producing a thermosetting resin. The imidazole dinitrile-containing compound has two structural modification sites on an imidazole ring, so that the prepared thermosetting resin has excellent structural modifiability. In addition, due to the unique aromatic heterocyclic structure, the thermosetting resin has potential functionality in the aspects of carbon materials, ionic liquids and the like, so that the prepared thermosetting resin has wide potential application value.

The above thermosetting resin based on an imidazole dinitrile-reactive group, the curing agent is a lewis acid/lewis base, or a compound containing a methylene/methine curing group.

The Lewis acid/Lewis base may be an aromatic amino compound having a curing functionPhenolic hydroxy compounds or metal salts, e.g. 3,3' - (1, 3-phenylenedi (oxy)) diphenylamine, ZnCl ₂The methylene/methine curing group containing compound can be 2,2' - (oxybis (4, 1-phenylene)) bis (3 α,4, 7,7a tetrahydro-1H-isoindole-1, 3(2H) -dione), and the like in a preferred implementation, the curing agent is an amino curing agent because the amino curing agent can form hydrogen bonds with the imidazole ring, increasing the uniformity of dispersion of the curing agent.

The preparation process for thermosetting resins differs for different types of compounds containing imidazole dinitriles, mainly divided into the following two types:

(A) when the imidazole dinitrile-containing compound has the structural formula I, III, IV or VII, since the compound in this case contains an autocatalytic group-NH-, it is possible to obtain a thermosetting resin by curing only the imidazole dinitrile-containing compound as a raw material. The specific operation is as follows: curing the compound containing the imidazole dinitrile at a gradient temperature in a nitrogen atmosphere,

keeping the temperature for 0-10 hours at the temperature T of more than or equal to 150 and less than or equal to 190 ℃,

keeping the temperature for 0-10 hours at the temperature of T more than or equal to 200 and less than or equal to 210 ℃,

keeping the temperature for 0-10 hours at the temperature of more than or equal to 230 and less than or equal to 250 ℃,

t is more than or equal to 290 and less than or equal to 300 ℃, the temperature is kept for 0.5 to 10 hours,

the temperature T is not less than 150 and not more than 190 ℃, the temperature T is not less than 200 and not more than 210 ℃, and the heat preservation time is not more than 230 and not more than 250 ℃ is not 0 at the same time;

or curing the compound containing the imidazole dinitrile at the following temperature and time in sequence:

keeping the temperature for 0-10 hours at the temperature T of more than or equal to 150 and less than or equal to 190 ℃,

keeping the temperature for 0-10 hours at the temperature of T more than or equal to 200 and less than or equal to 210 ℃,

keeping the temperature for 0-10 hours at the temperature of more than or equal to 230 and less than or equal to 250 ℃,

t is more than or equal to 290 and less than or equal to 300 ℃, the temperature is kept for 0-10 h,

keeping the temperature of T more than or equal to 350 and less than or equal to 380 ℃ for 0.5-10 h;

the temperature T is not less than 150 and not more than 190 ℃, the temperature T is not less than 200 and not more than 210 ℃, and the heat preservation time is not more than 230 and not more than 250 ℃ is not 0 at the same time;

after the curing was completed, the resultant product was furnace-cooled to room temperature.

(B) When the structural formula of the compound containing the imidazole dinitrile is I to VII, the compound containing the imidazole dinitrile is used for obtaining the thermosetting resin under the action of the curing agent, and the curing efficiency of the resin can be improved and the curing temperature can be reduced by adding the curing agent. The specific operation comprises the following steps:

(1) mixing a compound containing imidazole dinitrile and a curing agent according to the mass ratio of 10: (0.7-1.0) blending, and uniformly blending a compound containing imidazole dinitrile and a curing agent to obtain a blend;

(2) the resulting blend was cured under nitrogen atmosphere at the following temperatures and times in order:

keeping the temperature for 0-10 hours at the temperature T of more than or equal to 150 and less than or equal to 190 ℃,

keeping the temperature for 0-10 hours at the temperature of T more than or equal to 200 and less than or equal to 210 ℃,

keeping the temperature for 0-10 hours at the temperature of more than or equal to 230 and less than or equal to 250 ℃,

t is more than or equal to 290 and less than or equal to 300 ℃, the temperature is kept for 0.5 to 10 hours,

the temperature T is not less than 150 and not more than 190 ℃, the temperature T is not less than 200 and not more than 210 ℃, and the heat preservation time is not more than 230 and not more than 250 ℃ is not 0 at the same time;

or the obtained blend is cured according to the following temperature and time in sequence:

keeping the temperature for 0-10 hours at the temperature T of more than or equal to 150 and less than or equal to 190 ℃,

keeping the temperature for 0-10 hours at the temperature of T more than or equal to 200 and less than or equal to 210 ℃,

keeping the temperature for 0-10 hours at the temperature of more than or equal to 230 and less than or equal to 250 ℃,

t is more than or equal to 290 and less than or equal to 300 ℃, the temperature is kept for 0-10 h,

keeping the temperature of T more than or equal to 350 and less than or equal to 380 ℃ for 0.5-10 h;

the temperature T is not less than 150 and not more than 190 ℃, the temperature T is not less than 200 and not more than 210 ℃, and the heat preservation time is not more than 230 and not more than 250 ℃ is not 0 at the same time;

after the curing was completed, the resultant product was furnace-cooled to room temperature.

In the preparation method of the thermosetting resin based on the imidazole dinitrile reactive group, in the step (1), the compound containing the imidazole dinitrile and the curing agent are blended in the following two ways:

(i) dissolving a compound containing imidazole dinitrile and a curing agent in a solvent for mixing, and then spin-drying the obtained mixed solution; the solvent is tetrahydrofuran or acetone.

(ii) The imidazole dinitrile-containing compound and the curing agent are mixed by grinding.

According to the thermosetting resin prepared by the method, under the nitrogen atmosphere, the temperature of 5% of the weight loss of the resin can reach 570 ℃, and the carbon residue rate at 800 ℃ can reach 80%, which indicates that the prepared thermosetting resin has good thermal stability; the temperature at which 5% weight loss of the resin is observed, even in an air atmosphere, is not much different from that in a nitrogen atmosphere, indicating that the thermosetting phase resin prepared has good thermo-oxidative stability. And the imidazole group provided by the compound containing the imidazole dinitrile and the unique aromatic heterocyclic structure thereof enable the prepared resin to have excellent structure modifiability.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention takes imidazole dinitrile group as reactive group, and accelerates the curing under the action of curing group to prepare the thermosetting resin with excellent thermal stability and thermo-oxidative stability.

2. The imidazole group and the unique aromatic heterocyclic structure thereof provided by the compound containing the imidazole dinitrile lead the prepared thermosetting resin to have rich modifiable sites, thereby leading the prepared thermosetting resin to show excellent structure modifiable property.

3. The aromatic heterocyclic structure provided by the compound containing the imidazole dinitrile can enable the prepared thermosetting resin to have potential functionality in the aspects of preparing N-doped carbon materials, dielectric materials and the like, so that the prepared thermosetting resin has wide potential application value.

4. The invention is suitable for popularization and development in the field due to wide raw material sources, simple synthesis process and low cost.

Drawings

FIG. 1 is a rheological profile of a blend of DCI and m-APB of example 1 of the present invention.

FIG. 2 is an IR spectrum of a blend of DCI and m-APB of example 1 of the present invention before and after curing.

FIG. 3 shows the results of thermo-gravimetric analysis (TGA) test in example 1 of the present invention; wherein a is a thermogravimetric analysis curve of the DCI under the nitrogen atmosphere, b is a thermogravimetric analysis curve of the m-APB under the nitrogen atmosphere, c is a thermogravimetric analysis curve of a product obtained after the DCI and the m-APB are cured under the nitrogen atmosphere, and d is a thermogravimetric analysis curve of a product obtained after the DCI and the m-APB are cured under the air atmosphere.

Detailed Description

The technical solutions of the present invention are described in detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the following examples:

(1) TGA, T5%: the method is characterized in that a sample is subjected to temperature loss of 5% in a thermogravimetric analyzer TG at a heating rate of 10 ℃/min under a nitrogen atmosphere.

(2) The char yield refers to the residual weight of the sample at 800 ℃ in the thermogravimetric analyzer TG.