阅读说明：本技术 一种超支化聚酰亚胺及其制备方法 (Hyperbranched polyimide and preparation method thereof ) 是由 彭军 段瑨 沈奎 刘亦武 王进 刘含茂 许双喜 杨军 于 2021-08-02 设计创作，主要内容包括：本发明公开了一种超支化聚酰亚胺以及上述超支化聚酰亚胺的制备方法。本发明在原有聚酰亚胺制备体系中加入多官能团的核,反应过程以该核为核心进行星型聚合,可以得到超支化聚酰亚胺,在同等固含量和粘度条件下,其链段相对较多,分子量较大,流动性好,成膜材料的力学性能相对较好。(The invention discloses hyperbranched polyimide and a preparation method thereof. According to the invention, a core with multiple functional groups is added into the original polyimide preparation system, star polymerization is carried out by taking the core as a core in the reaction process, so that the hyperbranched polyimide can be obtained, and under the conditions of the same solid content and viscosity, the hyperbranched polyimide has relatively more chain segments, larger molecular weight, good fluidity and relatively better mechanical properties of a film-forming material.)

1. The hyperbranched polyimide is characterized in that the molecular structural formula is as follows:

wherein R is derivative of amino triphosphazene, N₁～N₆Is a polyimide structural unit.

2. The hyperbranched polyimide of claim 1, wherein the derivative of amino triphosphazene has the following molecular formula:

wherein-X-isOne or more of (a).

3. The hyperbranched polyimide of claim 1, wherein the molecular structural formula of the polyimide structural unit is as follows:

wherein A, B is a group which does not participate in the reaction in the process of synthesizing the polyimide by using the diamine monomer for synthesizing the polyimide and the dianhydride monomer for synthesizing the polyimide.

4. The hyperbranched polyimide according to claim 3, wherein the number of repeating units n in the polyimide structural unit is 10 to 200.

5. A method for preparing the hyperbranched polyimide of any one of claims 1 to 4, comprising the steps of: heating and reacting an amino triphosphazene derivative, a dianhydride monomer for polyimide synthesis and a diamine monomer for polyimide synthesis in an aprotic solvent to obtain homogeneous polyamic acid, and imidizing the homogeneous polyamic acid to obtain the hyperbranched polyimide.

6. The method according to claim 5, wherein the dianhydride monomer for polyimide synthesis comprises pyromellitic dianhydride, biphenyltetracarboxylic anhydride, polyanilides, 3',4,4' -benzophenonetetracarboxylic dianhydride, 2 '-bis- (3, 4-dicarboxyphenyl) hexafluoropropane, 3',4,4 '-bisphenylsulfone tetracarboxylic dianhydride, 1,2,4, 5-pyromellitic dianhydride, 3-bromopyromellitic dianhydride, 3, 6-bis (trifluoromethyl) -pyromellitic dianhydride, 3, 6-bis (methoxy) -pyromellitic dianhydride, 3',4,4 '-biphenyltetracarboxylic dianhydride, 2-diphenyl-4, 4',5,5 '-biphenyltetracarboxylic dianhydride, 2' -diphenyl-4, 4',5,5' -biphenyltetracarboxylic dianhydride, 3,3',4,4' -p-terphenyltetracarboxylic dianhydride, 2-bis (3, 4-dicarboxyphenyl) methane dianhydride, 2-bis (3, 4-dicarboxyphenyl) propane dianhydride, hexafluoro dianhydride, benzophenone tetracarboxylic dianhydride, 1, 3-bis (3, 4-dicarboxyphenyl) benzene dianhydride, 3, 5-bis (3, 4-dicarboxyphenyl) biphenyl dianhydride, 4,4 '-m-phenylenediamine diphenyl anhydride, 3',4,4 '-diphenyl ether dianhydride, 3',4,4 '-diphenyl sulfide dianhydride, 3',4,4 '-diphenyl sulfone dianhydride, 4,4' - (p-phenylene) diether dianhydride, 4,4'- (4,4' -diphenoxy) dianhydride, 3',4,4' -dimethyldiphenylsilanetetracarboxylic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, binaphthyl dianhydride, cyclobutane dianhydride, and 1, 4-bis (phenylmaleic anhydride) benzene.

7. The method according to claim 5, wherein the diamine monomer for polyimide synthesis comprises p-phenylenediamine, m-phenylenediamine, 4,4' -oxydianiline, 3,4' -diaminophenyl ether, diaminodiphenyl sulfone, 4,4' -diaminotriphenylp-phenylenediamine, 2, 5-diaminotoluene, 4- (4' -butoxy) biphenyl ester of 3, 5-diaminobenzoic acid, 2, 6-naphthalenediamine, diaminobiphenyl, 4,4' -diamino-2, 2' -dimethylbiphenyl, 4,4 "-diamino-p-terphenyl, 3' -dimethyl-4, 4' diaminodiphenylmethane, 4,4' -diaminobenzanilide, 2, 6-diaminopyridine, 2, 4' -diaminotoluene, 4,4' -diaminodiphenyl sulfone, and the like, One or more of 4-phenyl-2, 6-bis (4-aminophenyl) pyridine, 5(6) -amino-2- (3' -aminophenyl) benzimidazole, and 3, 6-diaminocarbazole.

8. The method of any one of claims 5-7, wherein the aprotic solvent comprises one or more of dimethylacetamide, diethylacetamide, N-dimethylsulfone, N-methylpyrrolidone, and dimethylsulfoxide.

9. The preparation method of any one of claims 5 to 7, wherein the reaction temperature of the heating reaction is-10 ℃ to 10 ℃, the solid content of the reaction system is 5 to 30%, and the reaction time is 6 to 10 hours.

10. The method according to any one of claims 5 to 7, wherein the imidization is carried out by raising the temperature to 300 to 450 ℃ at a rate of 5 ± 3 ℃/min, maintaining the temperature at the highest temperature for 5 to 20min, and then lowering the temperature at a rate of 5 ± 3 ℃/min.

Technical Field

The invention belongs to the field of high polymer materials, and particularly relates to polyimide and a preparation method thereof.

Background

Polyimide is one of organic polymer materials with excellent comprehensive performance, resists high temperature of more than 450 ℃, has long-term use temperature of more than 300 ℃, has no obvious melting point, has high insulating property and excellent performance which other engineering plastics do not have, and is widely applied to the special fields of aerospace, nano liquid crystal, separation membranes and laser lamps.

In the process of film formation of polyimide, excessive solvent needs to be volatilized, so that the mechanical film coating is limited in many occasions, the cost is reduced, the film formation is very thin, and the material needs to have good mechanical properties under the conditions of fixed viscosity and solid content. In the prior polyimide preparation process, the molecular weight can only be reduced due to solid content and viscosity, and the reduction of the molecular weight has certain influence on the mechanical property of the material, so that the mechanical property of the material is difficult to ensure.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects and shortcomings in the background technology, and provide hyperbranched polyimide and a preparation method thereof. In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a hyperbranched polyimide has a molecular structural formula as follows:

wherein R is derivative of amino triphosphazene, N₁-N₆Is a polyimide structural unit.

In the hyperbranched polyimide, the molecular structural formula of the derivative of the amino triphosphazene is preferably as follows:

wherein-X-isOne kind of (1).

In the invention, the-X-group is adopted, so that the mechanical property of the multi-branched polymer is improved, and the matching relation of the multi-branched polymer, a diamine monomer and a dianhydride monomer is good.

In the hyperbranched polyimide, preferably, the molecular structural formula of the polyimide structural unit is as follows:

wherein A, B is a group which does not participate in the reaction in the process of synthesizing the polyimide by using the diamine monomer for synthesizing the polyimide and the dianhydride monomer for synthesizing the polyimide.

In the hyperbranched polyimide, the number of repeating units n in the polyimide structural unit is preferably 10 to 200. More preferably 30 to 80.

As a general technical concept, the present invention also provides a preparation method of the hyperbranched polyimide, comprising the steps of: heating and reacting a derivative of amino triphosphazene (namely polyamine R), a dianhydride monomer for polyimide synthesis and a diamine monomer for polyimide synthesis in an aprotic solvent to obtain homogeneous polyamic acid, and imidizing the homogeneous polyamic acid to obtain the hyperbranched polyimide.

In the above-mentioned preparation method, the dianhydride monomer for polyimide synthesis preferably includes pyromellitic anhydride, biphenyltetracarboxylic anhydride, polyacene dianhydride, 3',4,4' -benzophenonetetracarboxylic dianhydride, 2' -bis- (3, 4-dicarboxyphenyl) hexafluoropropane, 3',4,4' -bisphenylsulfone tetracarboxylic dianhydride, 1,2,4, 5-pyromellitic dianhydride, 3-bromopyromellitic dianhydride, 3, 6-bis (trifluoromethyl) -pyromellitic dianhydride, 3, 6-bis (methoxy) -pyromellitic dianhydride, 3',4,4' -biphenyltetracarboxylic dianhydride, 2-diphenyl-4, 4',5,5' -biphenyltetracarboxylic dianhydride, 3',4,4' -p-biphenyltetracarboxylic dianhydride, 2, 2-bis (3, 4-dicarboxyphenyl) methane dianhydride, 2-bis (3, 4-dicarboxyphenyl) propane dianhydride, hexafluoro dianhydride, benzophenone tetracarboxylic dianhydride, 1, 3-bis (3, 4-dicarboxyphenyl) benzene dianhydride, 3, 5-bis (3, 4-dicarboxyphenyl) biphenyl dianhydride, 4,4' -m-phenylenediamine diphenylanhydride, 3',4,4' -diphenylether dianhydride, 3',4,4' -diphenylsulfide dianhydride, 3',4,4' -diphenylsulfone dianhydride, 4,4' - (p-phenylene) diether dianhydride, 4,4' - (4,4' -diphenoxy) dianhydride, 3',4,4' -dimethyldiphenylsilane tetracarboxylic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 1, 4' -naphthalene tetracarboxylic acid dianhydride, and mixtures thereof, One or more of binaphthyl dianhydride, cyclobutane dianhydride, and 1, 4-bis (phenylmaleic anhydride) benzene. More preferably, the dianhydride monomer for polyimide synthesis is pyromellitic anhydride or biphenyltetracarboxylic anhydride. More preferably, the dianhydride monomer for polyimide synthesis is pyromellitic anhydride.

In the above production method, it is preferable that the diamine monomer for polyimide synthesis includes p-phenylenediamine, m-phenylenediamine, 4,4 '-oxydianiline, 3,4' -diaminophenylether, diaminodiphenylsulfone, 4,4 '-diaminotriphenylp-phenylenediamine, 2, 5-diaminotoluene, 4- (4' -butoxy) biphenyl ester of 3, 5-diaminobenzoic acid, 2, 6-naphthalenediamine, diaminobiphenyl, 4,4 '-diamino-2, 2' -dimethylbiphenyl, 4,4 '-diamino-p-terphenyl, 3' -dimethyl-4, 4 'diaminodiphenylmethane, 4,4' -diaminobenzanilide, 2, 6-diaminopyridine, 4-phenyl-2, one or more of 6-bis (4-aminophenyl) pyridine, 5(6) -amino-2- (3' -aminophenyl) benzimidazole, and 3, 6-diaminocarbazole. More preferably, the diamine monomer for polyimide synthesis is p-phenylenediamine, m-phenylenediamine, 4' -oxydianiline. More preferably, the diamine monomer for polyimide synthesis is 4,4' -oxydianiline.

The research shows that the pyromellitic dianhydride and the 4,4' -oxydianiline are used as the dianhydride monomer and the diamine monomer for synthesizing the polyimide, the matching relationship between the dianhydride monomer and the diamine monomer and the derivative of the amino-triphosphazene is better, the dianhydride monomer and the diamine monomer are more favorable for star polymerization by taking the derivative of the amino-triphosphazene as the core and are outwards developed into a regular multi-branched polymer, and the mechanical property of final film forming is more favorable for ensuring.

In the preparation method, the preferable reaction temperature of the heating reaction is-10 ℃ to 10 ℃, the solid content of the reaction system is 5-30%, and the reaction time is 6-10 h. Too high a reaction temperature, exceeding 10 ℃ results in not high molecular weight of the polyamic acid resin, while too low a temperature results in too slow a reaction.

In the above preparation method, preferably, the aprotic solvent includes one or more of Dimethylacetamide (DMAC), diethylacetamide, N-dimethylsulfone, N-methylpyrrolidone, and dimethylsulfoxide.

In the above production method, preferably, the homogeneous polyamic acid is coated with a film, and then the solvent is removed at a high temperature to complete imidization. The imidization and the film forming process are carried out synchronously, and the production efficiency is improved.

In the preparation method, preferably, the imidization is carried out by raising the temperature to 300-450 ℃ at a rate of 5 +/-3 ℃/min, keeping the temperature at the highest temperature for 5-20 min, and then lowering the temperature at a rate of 5 +/-3 ℃/min. The temperature rise speed is too fast, so that the solvent on the surface cannot be volatilized in time, the imidization is incomplete, and the material is possibly oxidized due to too slow temperature rise speed; the maximum temperature is too high and may cause degradation of the material.

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

1. according to the invention, a nucleus with multiple functional groups is added into an original polyimide preparation system, star polymerization is carried out by taking the nucleus as a core in the reaction process, and the hyperbranched polyimide can be obtained.

2. The hyperbranched polyimide has more branched chains, and has the advantages of high fluidity, low viscosity, good film forming mechanical property and the like.

Detailed Description

In order to facilitate an understanding of the present invention, the present invention will be described more fully and in detail with reference to the preferred embodiments, but the scope of the present invention is not limited to the specific embodiments described below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

A hyperbranched polyimide has a molecular structural formula as follows:

r is a derivative of aminotriphosphazene, N₁～N₆The polyimide structural unit is obtained by polymerizing pyromellitic dianhydride and 4,4' -oxydianiline.

The structural formula of the derivative R of the amino triphosphazene is as follows:

wherein-X-is X1:or X2

The preparation method of the hyperbranched polyimide comprises the following steps:

(1) the aprotic solvent is put into a reaction kettle, the temperature is adjusted to-5 ℃, the nitrogen replaces the air in the kettle, and the stirring is started.

(2) Adding the derivative R of the amino triphosphazene into a reaction kettle, adding all diamine monomers, slowly adding dianhydride monomers for multiple times, wherein the adding amount of the dianhydride monomers is 60%, 30%, 7%, 2% and 1% of the weight of the dianhydride respectively every 1 hour, and after the dianhydride monomers are added, keeping stirring for 3 hours, and then carrying out vacuum defoaming to obtain yellow homogeneous polyamic acid (PAA).

(3) Uniformly coating the PAA resin after bubble removal on a clean glass plate, putting the glass plate into an oven, heating to 350 ℃ at the speed of 5 ℃/min, keeping the temperature for 10min, and then cooling to the normal temperature at the speed of 5 ℃/min.

(4) And (3) putting the glass plate into water for 30min, and then removing the film from the glass plate to obtain the hyperbranched polyimide.

The kinds and amounts of the aprotic solvent, diamine monomer, dianhydride monomer, and aminotriphosphazene derivative R in the above preparation method are shown in Table 1 below.

Table 1: material recipe tables (unit: g) in examples 1 to 6 and comparative example 1

In the above table, the amine R1 is the derivative R of the amino triphosphazene with the structural formula X1, and the amine R2 is the derivative R of the amino triphosphazene with the structural formula X2.

Example 1:

the structure and preparation method of the hyperbranched polyimide of this example are as above, and the specific amount is shown in table 1 above.

Example 2:

example 2 is compared to example 1 with the difference that the aprotic solvent, the diamine monomer and the derivative R of aminotriphosphazene are used in different amounts, see in particular table 1 above.

Example 3:

example 3 is compared to example 1 with the difference that the aprotic solvent, the diamine monomer and the derivative R of aminotriphosphazene are used in different amounts, see in particular table 1 above.

Example 4:

example 4 differs from example 1 in the type of derivative R of the aminotriphosphazene, see in particular Table 1 above.

Example 5:

example 5 differs from example 2 in the type of derivative R of the aminotriphosphazene, see in particular Table 1 above.

Example 6:

example 6 differs from example 3 in the type of derivative R of the aminotriphosphazene, see in particular Table 1 above.

Comparative example 1:

comparative example 1 is different from example 1 in the amount of the aprotic solvent and the diamine monomer, and the derivative R of aminotriphosphazene is not used in comparative example 1, see table 1 above.

The property data of the polyimides prepared in examples 1 to 6 and comparative example 1 are shown in table 2 below.

Table 2: performance test results of polyimides according to examples 1 to 6 and comparative example 1

As can be seen from Table 2, the mechanical properties of examples 1-6 are all superior to those of the non-hyperbranched polymer, and the viscosity of the material is reduced along with the increase of the amount of the branched core under the condition of almost the number average molecular weight, so that the high solid content can be maintained in part of process applications, the viscosity is low, and the mechanical properties after film formation are good.