Catalyst composition for improving molecular weight of polyimide and application method thereof

Abstract

The invention belongs to the technical field of polyimide resin, and discloses a catalyst composition for improving the molecular weight of polyimide and an application method thereof.The catalyst composition is prepared from, by weight, 80-95% of basic solvent dimethylacetamide, 2-13% of dimethylolpropionic acid and 3-15% of dimethylformamide, the preparation method comprises the following steps: adding dimethylacetamide, dimethylolpropionic acid and dimethylformamide into a reaction kettle in proportion, and stirring at room temperature for 1 hour at 1000rmp to obtain the catalyst composition. By adding the catalyst composition with the same polarity, the rate of polymerization reaction is greatly improved, and the polymerization degree and molecular weight of macromolecules are improved, so that the mechanical properties of finished products such as membranes, filaments and profiles in the later period can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of polyimide resins, and more specifically, to a catalyst composition for increasing the molecular weight of polyimide and an application method thereof. Background Art

[0002] As a cutting-edge structural or functional material, polyimide is widely used in aerospace, aviation, microelectronics, electromechanical, instrumentation, chemical industry and other fields due to its excellent properties such as high temperature resistance, friction resistance, corrosion resistance, radiation resistance, oxidation resistance, low density, high mechanical strength, good electrical insulation performance, and diversity of synthesis and processing methods.

[0003] Polyimides are a class of polymer compounds containing an imide ring on the main chain, which are formed by the organic polymerization reaction of diamines and dianhydrides. The differences in the molecular structure of their monomers and their molecular weight distribution will give them different thermodynamic, optical and mechanical properties.

[0004] At present, domestic organic polymer polyimide is basically polymerized by the organic solvent DMAC (dimethylacetamide), but the polymerization reaction efficiency is very low, the speed is very slow, and the molecular weight distribution is very wide, which brings difficulties to the next step of material molding. Summary of the invention

[0005] In order to solve the above problems, the present application provides a catalyst composition for increasing the molecular weight of polyimide and an application method thereof.

[0006] The present application provides a catalyst composition for increasing the molecular weight of polyimide and an application method thereof using the following technical solutions:

[0007] A catalyst composition for increasing the molecular weight of polyimide comprises, by weight percentage, 80-95% of a basic solvent dimethylacetamide, 2-13% of dimethylolpropionic acid, and 3-15% of dimethylformamide. Dimethylacetamide, dimethylolpropionic acid and dimethylformamide are added into a reaction kettle in proportion, and stirred at 1000 rpm for 1 hour at room temperature to obtain the catalyst composition.

[0008] The invention discloses an application method of a catalyst composition for improving the molecular weight of polyimide. In the initial stage of polymerization of pyromellitic dianhydride and diaminodiphenyl ether, the catalyst composition is added as a polar catalyst system, and the temperature is controlled at 110 to 150 degrees under low-speed stable stirring to obtain a polyimide after filtering and drying the obtained mixture.

[0009] Furthermore, the added catalyst composition accounts for 0.2% to 15% by mass.

[0010] Furthermore, the stirring speed is 200-300 rpm.

[0011] A catalyst composition for increasing the molecular weight of polyimide, characterized in that, by weight percentage, it comprises 98.8-99.6% of a basic solvent dimethylacetamide, 0.1%-0.5% of dimethylolpropionic acid, and 0.3-0.7% of dimethylformamide, and is stirred at 1000 rpm for 1 hour at room temperature to obtain the catalyst composition.

[0012] In summary, the present application includes at least one of the following beneficial technical effects:

[0013] The present invention greatly increases the rate of polymerization reaction by adding a catalyst composition of the same polarity, and increases the degree of polymerization and molecular weight of the polymer, thereby improving the mechanics and mechanical properties of the subsequent finished products such as membranes, wires and profiles. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present application will be described clearly and completely below; obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application without making creative work are within the scope of protection of the present application.

[0015] Embodiment 1:

[0016] The catalyst composition is obtained by adding 98.8% of the basic solvent dimethylacetamide, 0.5% of dimethylol propionic acid and 0.7% of dimethylformamide by weight, stirring at 1000 rpm for 1 hour at room temperature. In the initial stage of polymerization of pyromellitic dianhydride and diaminodiphenyl ether, adding 0.2% of the total mass of the catalyst composition as a polar catalyst system, stirring steadily at 200-300 rpm, controlling the temperature at 110-150 degrees for reaction, filtering and drying the obtained mixture to obtain polyimide.

[0017] Embodiment 2:

[0018] The catalyst composition is obtained by adding 99.2% of the basic solvent dimethylacetamide, 0.3% of dimethylol propionic acid and 0.5% of dimethylformamide by weight, stirring at 1000 rpm for 1 hour at room temperature. In the initial stage of polymerization of pyromellitic dianhydride and diaminodiphenyl ether, adding 5% of the total mass of the catalyst composition as a polar catalyst system, stirring steadily at 200-300 rpm, controlling the temperature at 110-150 degrees for reaction, filtering the obtained mixture, and drying it to obtain polyimide.

[0019] Embodiment 3:

[0020] The catalyst composition is obtained by adding 99.6% of the basic solvent dimethylacetamide, 0.1% of dimethylol propionic acid and 0.3% of dimethylformamide by weight, stirring at 1000 rpm for 1 hour at room temperature. In the initial stage of polymerization of pyromellitic dianhydride and diaminodiphenyl ether, adding 15% of the total mass of the catalyst composition as a polar catalyst system, stirring steadily at 200-300 rpm, controlling the temperature at 110-150 degrees for reaction, filtering and drying the obtained mixture to obtain polyimide.

[0021] Comparative Example:

[0022] In the initial stage of polymerization of pyromellitic dianhydride and diaminodiphenyl ether, 15% of the total mass of dimethylacetamide is added, the mixture is stirred steadily at 200-300 rpm, the temperature is controlled at 110-150 degrees to react, and the obtained mixture is filtered and dried to obtain polyimide.

[0023] The preparation processes of Examples 1 to 3 and the prepared polyimide resin products were tested for performance, as shown in Table 1:

[0024] Table 1 Preparation process of Examples 1 to 3 and properties of the finished polyimide resin

[0025] Average degree of polymerization after 1h reaction Finished product glass transition temperature / ℃ Finished product weight average molecular weight / Mw Example 1 96 388 27900 Example 2 95 361 27500 Example 3 95 375 27600 Comparative Example 20 345 25000

[0026] From the performance test results, it can be seen that the polyimide resin prepared by the method of the present invention takes much less time than ordinary polymerization reaction, and about 95% of the polymerization reaction can be completed in about 1 hour, and the molecular weight of the product can be about 10% higher than that of ordinary reactions.

[0027] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A catalyst composition for increasing the molecular weight of polyimide, characterized in that: Calculated by weight percentage, the catalyst composition comprises 80-95% of a basic solvent dimethylacetamide, 2-13% of dimethylolpropionic acid, and 3-15% of dimethylformamide. Dimethylacetamide, dimethylolpropionic acid, and dimethylformamide are added into a reaction kettle in proportion, and stirred at 1000 rpm for 1 hour at room temperature to obtain the catalyst composition.

2. A method for applying a catalyst composition for increasing the molecular weight of polyimide, characterized in that: In the initial stage of polymerization of pyromellitic dianhydride and diaminodiphenyl ether, a catalyst composition is added as a polar catalyst system, and the temperature is controlled at 110 to 150 degrees under slow and stable stirring to obtain a polyimide after filtering and drying the obtained mixture.

3. A method for synthesizing polyimide according to claim 2, characterized in that: The added catalyst composition accounts for 25% to 50% by mass.

4. A method for synthesizing polyimide according to claim 2, characterized in that: The stirring speed is 200-300 rpm.