CN118420906A - Synthesis method of polyamide imide - Google Patents

Abstract

The present invention relates to the technical field of polyamide-imide material synthesis, and in particular to a method for synthesizing polyamide-imide. The method of the present invention comprises the following steps: adding trimellitic anhydride chloride and diamine compounds to an organic solvent to dissolve, and then adding an acid binding agent and a phase transfer catalyst to react to obtain a polyamide-amic acid solution; the polyamide-amic acid solution is subjected to imidization treatment to obtain polyamide-imide; the acid binding agent is an oxide, hydride or weak acid salt of an alkali metal or alkaline earth metal. The present invention adopts non-flammable oxides/hydrides/weak acid salts of alkali metals/alkaline earth metals as acid binding agents, and simultaneously adds a phase transfer catalyst to increase the solubility of inorganic strong base weak acid salts in a reaction system, greatly avoiding the safety risks of traditional acid binding agents, and improving the safety of preparing polyamide-imide by an acyl chloride method. The raw materials of the acid binding agent of the present invention are easy to obtain and are easy to be applied in large-scale industrialization.

Description

A kind of synthetic method of polyamide-imide

Technical Field

The invention relates to the technical field of polyamide-imide material synthesis, in particular to a method for synthesizing polyamide-imide.

Background technique

Polyamideimide (PAI) is a class of high-performance polymers derived from polyimide. Its molecular chain contains both imide structure and amide structure, and has the characteristics of solvent resistance, corrosion resistance, high temperature resistance, and impact resistance. Compared with polyimide, the molecular chain contains both rigid imide rings and flexible amide groups. Therefore, polyamideimide retains the excellent heat resistance and mechanical properties of polyimide, and solves its disadvantage of difficult processing, greatly increases tensile strength and impact resistance, and has good creep properties. Therefore, the excellent performance of PAI is widely used in coatings, aerospace and other industries, especially in the electronics field, it has broad application prospects and is highly valued by people in various industries.

Researchers have currently developed a variety of methods for preparing PAI: including the acyl chloride method, polycondensation method, and diisocyanate method, among which the most common and simplest method is the acyl chloride method. The acyl chloride method uses trimellitic anhydride chloride and diamine as reaction monomers, which has high reaction activity and simple post-processing, but hydrogen chloride waste gas is produced during the preparation process, so an acid binding agent needs to be added to absorb the hydrogen chloride. Traditional acid binding agents mainly include triethylamine, propylene oxide, etc., but triethylamine and propylene oxide are flammable and explosive reagents, and the safety risks in transportation, storage, and use are relatively high.

Therefore, providing a polyamide-imide synthesis method using an acid-binding agent with a lower flammability and explosion level is of great significance to the technical field of polyamide-imide material synthesis.

Summary of the invention

Based on the above content, the present invention provides a method for synthesizing polyamide-imide. The method of the present invention uses non-flammable oxides/hydrides/weak acid salts of alkali metals/alkaline earth metals as acid-binding agents, and simultaneously adds a phase transfer catalyst to increase the solubility of the inorganic strong base weak acid salt in the reaction system, thereby greatly avoiding the safety risks of traditional acid-binding agents.

To achieve the above object, the present invention provides the following solutions:

One of the technical solutions of the present invention is a method for synthesizing polyamide-imide, comprising the following steps:

Adding trimellitic anhydride chloride and a diamine compound into an organic solvent to dissolve them, then adding an acid binding agent and a phase transfer catalyst to react to obtain a polyamide-amic acid solution;

Performing imidization treatment on the polyamide-amic acid solution to obtain polyamide-imide;

The acid binding agent is an oxide, a hydride or a weak acid salt of an alkali metal or an alkaline earth metal.

A second technical solution of the present invention is a method for improving the safety in the synthesis process of polyamide-imide, which adopts the above-mentioned synthesis method of polyamide-imide.

The present invention discloses the following technical effects:

The present invention adopts non-flammable oxides/hydrides/weak acid salts of alkali metals/alkaline earth metals as acid binding agents, and simultaneously adds a phase transfer catalyst to increase the solubility of the inorganic strong base weak acid salt in the reaction system, thereby greatly avoiding the safety risks of traditional acid binding agents and improving the safety of the process of preparing polyamide-imide by the acyl chloride method.

The raw materials of the acid binding agent of the invention are easily available and can be easily applied in large-scale industrialization.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG. 1 is a thermogravimetric graph of the polyamide-imide powders prepared in Example 1, Example 2, and Example 3.

FIG. 2 is an infrared image of the polyamide-imide powder prepared in Example 1, Example 2 and Example 3.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and/or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

The "room temperature" described in the present invention, unless otherwise specified, refers to 20-30°C.

The first aspect of the present invention provides a method for synthesizing polyamide-imide, comprising the following steps:

Adding trimellitic anhydride chloride and a diamine compound into an organic solvent to dissolve them, then adding an acid binding agent and a phase transfer catalyst to react to obtain a polyamide-amic acid solution;

Performing imidization treatment on the polyamide-amic acid solution to obtain polyamide-imide;

The acid binding agent is an oxide, a hydride or a weak acid salt of an alkali metal or an alkaline earth metal.

In some embodiments of the present invention, the acid binding agent is at least one of calcium oxide, magnesium oxide, sodium oxide, calcium hydride, magnesium hydride, sodium hydride, sodium acetate, potassium acetate, sodium formate, potassium formate, sodium citrate, potassium citrate, sodium sorbate, potassium sorbate, sodium malate and potassium malate.

In some embodiments of the present invention, the phase transfer catalyst is at least one of 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6, benzo-18-crown-6, cyclohexane-18-crown-6, benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride and tetradecyltrimethylammonium chloride.

In the present invention, the phase transfer catalyst is used to increase the solubility of the acid binding agent in the reaction system.

In some embodiments of the present invention, the diamine compound is at least one of o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,6-diaminotoluene, 1,4-diaminotrifluorotoluene, 3,5-diaminotrifluorotoluene, 4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether and 4,4'-diaminodiphenylmethane.

In some embodiments of the present invention, the molar ratio of the trimellitic anhydride chloride to the diamine compound is 1:1; the molar ratio of the acid binding agent to the trimellitic anhydride chloride is (0.4-2):1; and the mass ratio of the phase transfer catalyst to the acid binding agent is 0.1-0.2.

Too little amount of the acid binder will result in residual hydrogen chloride, while too much amount of the acid binder will result in waste and increase the difficulty of solvent recovery. Therefore, the preferred amount of the acid binder in the present invention is limited to the above molar ratio.

Too little phase transfer catalyst may result in a slow reaction rate, while too much phase transfer catalyst may result in an excess of catalyst, affecting the selectivity and yield of the reaction. Therefore, the preferred amount of the phase transfer catalyst in the present invention is limited to the above mass ratio.

In some embodiments of the present invention, the organic solvent is at least one of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, dioxane and dimethyl sulfoxide.

In some embodiments of the present invention, the reaction time is 1-12 hours.

In some embodiments of the present invention, the imidization treatment further includes the steps of adding the polyamide-amic acid solution into water to obtain a filamentous polymer, and crushing and drying the filamentous polymer.

The reaction scheme of the method of the present invention is as follows:

in

A second aspect of the present invention provides a method for improving the safety during the synthesis of polyamide-imide, using the above-mentioned method for synthesizing polyamide-imide.

Example 1

Step 1: Add 50 mmol (10.0118 g) of 4,4'-diaminodiphenyl ether and 125 mL of N,N-dimethylacetamide to a reaction vessel equipped with a nitrogen inlet, a water separator, a temperature measuring device and a stirring device, and stir until the solution is clear. Add 50 mmol (10.5285 g) of trimellitic anhydride chloride to the solution, stir until the solution is clear, then add 60 mmol (4.08 g) of sodium formate and 0.48 g of 18-crown ether-6, and stir for 5 hours to obtain a polyamide-amic acid solution.

Step 2, pour the polyamide-amic acid solution into deionized water to obtain a filamentous polymer, crush it, and dry it. The obtained polymer powder is vacuum treated according to a certain temperature increase program (200° C. for 1 hour, 250° C. for 1 hour, 300° C. for 1 hour, and the temperature increase rate is 10-20° C./min) to obtain polyamide-imide powder.

Example 2

The only difference from Example 1 is that 125 mL of N,N-dimethylacetamide in step 1 is replaced by 200 mL of N,N-dimethylformamide, 60 mmol of sodium formate is replaced by 30 mmol (1.68 g) of calcium oxide, and 0.48 g of 18-crown ether-6 is replaced by 0.25 g of benzo-18-crown ether-6; the remaining steps and parameters are the same as those in Example 1; and polyamideimide powder is prepared.

Example 3

The only difference from Example 1 is that 125 mL of N,N-dimethylacetamide in step 1 is replaced by 140 mL of N-methylpyrrolidone, 60 mmol of sodium formate is replaced by 30 mmol (1.21 g) of magnesium oxide, and 0.48 g of 18-crown ether-6 is replaced by 0.22 g of 15-crown ether-5; the remaining steps and parameters are the same as those in Example 1; and polyamideimide powder is prepared.

FIG. 1 is a thermogravimetric graph of the polyamide-imide powders prepared in Example 1, Example 2, and Example 3.

FIG. 2 is an infrared image of the polyamide-imide powder prepared in Example 1, Example 2 and Example 3.

As can be seen from FIG. 1 and FIG. 2 , the present invention successfully synthesizes polyamide-imide; the thermogravimetric curve and infrared graph of the polyamide-imide obtained by changing the type of the acid-binding agent have the same shape and trend.

Example 4

The only difference from Example 1 is that 50 mmol (10.0118 g) of 4,4'-diaminodiphenyl ether in step 1 is replaced by 50 mmol (9.9130 g) of 4,4'-diaminodiphenylmethane, 60 mmol of sodium formate is replaced by 20 mmol (5.16 g) of sodium citrate, and 0.48 g of 18-crown ether-6 is replaced by 0.78 g of benzyltriethylammonium chloride; the remaining steps and parameters are the same as those in Example 1; and polyamideimide powder is prepared.

Example 5

The only difference from Example 1 is that 50 mmol (10.0118 g) of 4,4'-diaminodiphenyl ether in step 1 is replaced by 50 mmol (9.9130 g) of 4,4'-diaminodiphenylmethane, 60 mmol of sodium formate is replaced by 60 mmol (4.92 g) of sodium acetate, and 0.48 g of 18-crown ether-6 is replaced by 0.60 g of tetrabutylammonium hydrogen sulfate; the remaining steps and parameters are the same as those in Example 1; and polyamideimide powder is prepared.

Example 6

The only difference from Example 1 is that 50 mmol (10.0118 g) of 4,4'-diaminodiphenyl ether in step 1 is replaced by 50 mmol (9.2120 g) of 4,4'-diaminobiphenyl, 60 mmol of sodium formate is replaced by 20 mmol (6.13 g) of potassium citrate, and 0.48 g of 18-crown ether-6 is replaced by 0.92 g of trioctylmethylammonium chloride; the remaining steps and parameters are the same as those in Example 1; and polyamideimide powder is prepared.

Example 7

The only difference from Example 1 is that 50 mmol (10.0118 g) of 4,4'-diaminodiphenyl ether in step 1 is replaced by 50 mmol (5.4070 g) of o-phenylenediamine, 60 mmol of sodium formate is replaced by 30 mmol (5.88 g) of sodium malate, and 0.48 g of 18-crown ether-6 is replaced by 0.70 g of tetradecyltrimethylammonium chloride; the remaining steps and parameters are the same as those in Example 1; and polyamideimide powder is prepared.

Example 8

The only difference from Example 1 is that 50 mmol (10.0118 g) of 4,4'-diaminodiphenyl ether in step 1 is replaced by 50 mmol (9.2120 g) of 4,4'-diaminobiphenyl, 60 mmol of sodium formate is replaced by 60 mmol (9.01 g) of potassium sorbate, and 0.48 g of 18-crown ether-6 is replaced by 1.35 g of benzyltriethylammonium chloride; the remaining steps and parameters are the same as those in Example 1; and polyamideimide powder is prepared.

The thermal decomposition temperatures of 5% and 10% polyamide-imide powders prepared in Examples 1-8 are shown in Table 1.

Table 1

The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims (9)

1. A method for synthesizing polyamide imide, which is characterized by comprising the following steps:

adding trimellitic anhydride acyl chloride and diamine compound into an organic solvent for dissolution, and then adding an acid binding agent and a phase transfer catalyst for reaction to obtain a polyamide-acid solution;

Imidizing the polyamide-amic acid solution to obtain polyamide imide;

the acid binding agent is an oxide, a hydride or a weak acid salt of alkali metal or alkaline earth metal.

2. The method for synthesizing polyamideimide according to claim 1, wherein the acid binding agent is at least one of calcium oxide, magnesium oxide, sodium oxide, calcium hydride, magnesium hydride, sodium acetate, potassium acetate, sodium formate, potassium formate, sodium citrate, potassium citrate, sodium sorbate, potassium sorbate, sodium malate, and potassium malate.

3. The method for synthesizing polyamideimide according to claim 1, wherein the phase transfer catalyst is at least one of 12-crown-4, 15-crown-5, 18-crown-6, dibenzo 18-crown-6, benzo 18-crown-6, cyclohexane-18-crown-6, benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bisulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, and tetradecyltrimethylammonium chloride.

4. The method for synthesizing polyamide-imide according to claim 1, wherein the diamine compound is at least one of o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2, 4-diaminotoluene, 2, 5-diaminotoluene, 2, 6-diaminotoluene, 1, 4-diaminobenzotrifluoride, 3, 5-diaminobenzotrifluoride, 4' -diaminobiphenyl, 4' -diaminodiphenyl ether, and 4,4' -diaminodiphenyl methane.

5. The method for synthesizing polyamideimide according to claim 1, wherein the molar ratio of the acid-binding agent to the trimellitic anhydride acid chloride is (0.4-2): 1; the mass ratio of the phase transfer catalyst to the acid binding agent is 0.1-0.2.

6. The method for synthesizing polyamideimide according to claim 1, wherein the organic solvent is at least one of N, N-dimethylacetamide, N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, dioxane and dimethylsulfoxide.

7. The method for synthesizing polyamideimide according to claim 1, wherein the reaction time is 1 to 12 hours.

8. The method for synthesizing polyamideimide according to claim 1, further comprising the steps of adding the polyamideimide acid solution to water to obtain a filamentous polymer, and pulverizing and drying the filamentous polymer before the imidization treatment.

9. A method for improving safety in the synthesis of polyamideimide, characterized in that the polyamideimide synthesis method according to any one of claims 1to 8 is used.