CN111499866B - Preparation method of high-efficiency catalytic curing phenylacetylene-terminated polyimide resin system - Google Patents

Abstract

A preparation method of a phenylacetylene-terminated polyimide resin system with high-efficiency catalytic curing belongs to the field of materials. The method comprises the following steps: preparing a phenylacetylene end-capped polyimide resin solution, adding a novel high-efficiency catalyst into a resin system, carrying out gradient curing on the resin system added with the novel high-efficiency compound catalyst, firstly curing at 120 ℃ for 1h, then curing at 240 ℃ for 2h, and finally curing at 300 ℃ for 3-4 h to obtain the completely cured phenylacetylene end-capped polyimide resin. The invention has the advantages that: the curing temperature of the phenylethynyl terminated polyimide resin prepared by the invention is obviously reduced, and the highest curing temperature is not more than 300 ℃. The phenylethynyl terminated polyimide resin has reliable low-temperature curing process, adopts a novel high-efficiency catalyst to catalyze the curing reaction, ensures uniform reaction, is simple to operate, has stable process, and is suitable for industrial production.

Description

A kind of preparation method of high-efficiency catalytic curing of phenylacetylene-terminated polyimide resin system

technical field

The invention belongs to the field of using resin, and in particular relates to a preparation method of a high-efficiency catalytic curing phenylacetylene-terminated polyimide resin system.

Background technique

Phenylacetylene-terminated polyimide is a high-performance resin developed around the 1990s. Its molecular structure contains an imide five-membered heterocyclic structure, which is composed of imide oligomers containing active phenylacetylene end groups. It is formed by curing and cross-linking, and the cured product is mainly aromatic structure. This structure endows the polyimide resin with a high glass transition temperature, above 270°C, it can be used for a long time at high temperature, and the thermal decomposition temperature can reach above 500°C. At the same time, its mechanical properties are also very good, with low thermal expansion coefficient, good dielectric properties, widely used in aviation, aerospace, microelectronics, nano, liquid crystal, separation membrane, laser and other high temperature fields.

However, due to the conjugation effect and steric hindrance effect of the phenylethynyl group, the curing of the phenylethynyl-terminated polyimide needs to overcome a lot of resistance, the activation energy is very high, and the curing temperature is above 370 °C. Long-term curing at high temperature often results in more residual stress in the cured product, resulting in poor stability of the service performance of the material, which seriously hinders the development and large-scale application of phenylacetylene-terminated polyimide resin and related materials.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problem of high curing temperature of phenylacetylene-terminated polyimide resin, and provide a kind of preparation method of high-efficiency catalytic curing of phenylacetylene-terminated polyimide resin system, the prepared phenylacetylene-terminated polyimide resin system The imide resin can still maintain excellent heat resistance.

Aiming at the problem of high curing temperature of the phenylacetylene-terminated polyimide resin, the invention adds a free radical catalyst to initiate crosslinking of the phenylacetylene group, and uses a coordination catalyst to directional control the crosslinking structure of the polyimide resin. The free radical catalyst (cumyl hydroperoxide) and the coordination catalyst (cobalt naphthenate) are selected to co-catalyze the phenylacetylene-terminated polyimide, and the synergistic effect of the two catalysts is used to enhance the curing reaction of the resin. Catalytic effect, and then reduce the curing temperature of the resin system, to achieve the purpose of reducing the curing temperature.

To achieve the above object, the technical scheme adopted by the present invention is as follows:

A preparation method of an efficient catalytic curing phenylacetylene-terminated polyimide resin system, the specific steps of the method are as follows:

Step 1: Prepare a phenylacetylene terminated polyimide resin with a mass fraction of 60-80%, and at room temperature, add a new type of high-efficiency catalyst to the obtained resin and mix it evenly. The mass ratio is 100:1～4:1, at 60℃, put the resin glue liquid mixture system into a vacuum oven for vacuum treatment, and the treatment time is 1～2h;

Step 2: Gradient curing of the resin system with the catalyst added: First, cure at 120 to 140 °C for 1 h, then at 240 to 250 °C for 2 to 3 hours, and finally at 300 °C for 3 to 4 hours, i.e. A fully cured phenylethynyl terminated polyimide resin is obtained.

Further, in step 1, the phenylacetylene-terminated polyimide resin is 60 parts, and 1,4-dioxane is 40 parts; the resin system is composed of cumene hydroperoxide and cobalt naphthenate. The mass ratio is 100:4:1.

Further, in the second step, the gradient curing system is curing at 120°C for 1 hour, then at 240°C for 2 hours, and finally at 300°C for 3 hours.

Further, in step 1, the polyimide resin terminated by the phenylacetylene group is 80 parts, the 1,4-dioxane is 20 parts, and the resin system is composed of cumene hydroperoxide and cobalt naphthenate. The mass ratio is 100:3:1.

Further, in step 2, the gradient curing system is curing at 140°C for 1 hour, then at 250°C for 2 hours, and finally at 300°C for 4 hours.

Further, in step 1, the polyimide resin terminated by the phenylacetylene group is 75 parts, the 1,4-dioxane is 25 parts, and the resin system is composed of cumene hydrogen peroxide and cobalt naphthenate. The mass ratio is 100:1:1.

Further, in step 2, the gradient curing system is curing at 125°C for 1 hour, then at 245°C for 2 hours, and finally at 300°C for 3 hours.

Further, in step 1, the polyimide resin terminated by the phenylacetylene group is 75 parts, the 1,4-dioxane is 25 parts, and the resin system is composed of cumene hydroperoxide and cobalt naphthenate. The mass ratio is 100:4:1.

Further, in step 2, the gradient curing system is curing at 130°C for 1 hour, then at 245°C for 2 hours, and finally at 300°C for 3 hours.

Further, in step 1, at room temperature, the resin glue solution mixture system is put into a vacuum oven for vacuum treatment, and the treatment time is 1.5h.

The beneficial effects of the present invention relative to the prior art are:

The curing temperature of the phenylacetylene-terminated polyimide resin prepared by the invention is obviously lowered, and the maximum curing temperature does not exceed 300° C., which is far lower than the curing temperature of the phenylacetylene-terminated polyimide resin in the prior art, which is 371° C.; The phenylethynyl-terminated polyimide resin of the present invention still maintains its excellent heat resistance (T5%≥520°C) at the curing temperature of ≤300°C. In the present invention, the low-temperature curing process of the phenylacetylene-terminated polyimide resin is reliable, and the novel and high-efficiency compound catalyst is used to catalyze the curing reaction, so that the reaction is uniform, the operation is simple, the process is stable, and is suitable for industrial production.

Description of drawings

为样品一，

为样品二；Fig. 1 is the infrared analysis spectrum of the low-temperature curing phenylacetylene-terminated polyimide resin of the present invention; wherein,

For sample one,

for sample two;

为样品一，

为样品二。Fig. 2 is the TGA analysis spectrum of the low-temperature curing phenylacetylene-terminated polyimide resin of the present invention; wherein,

For sample one,

for sample two.

Detailed ways

Those skilled in the art can understand that the above-mentioned embodiments are specific examples for realizing the present invention, and in practical applications, various changes in form and details can be made without departing from the spirit and the spirit of the present invention. scope.

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the following will describe the spirit of the contents disclosed in the present invention in detail. Changes and modifications may be made to the techniques taught in this disclosure without departing from the spirit and scope of this disclosure.

The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

The present invention consists of two parts. The first part is the design of new efficient catalysts. Because the curing temperature of the phenylacetylene-terminated polyimide resin is high and the resistance of the curing reaction is large, the present invention designs a new type of high-efficiency compound catalyst, which can effectively reduce the activation energy of the curing reaction, so that the phenylacetylene-terminated polyimide Urethane systems can cure at low temperatures while maintaining excellent heat resistance. The invention greatly reduces the curing reaction activation energy of the phenylethynyl-terminated polyimide resin through the synergistic effect of cumene hydrogen peroxide and cobalt naphthenate, thereby realizing low-temperature curing. When the phenylacetylene-terminated polyimide resin is cured, a free radical polymerization reaction mainly occurs. Both cumene hydroperoxide and cobalt naphthenate have a certain catalytic reaction to the free radical polymerization reaction, so they are used as catalysts for the curing system. , so that the activation energy of the reaction is reduced, so as to achieve low temperature curing. The mechanism of this novel high-efficiency compound catalyst catalyzing the curing system of phenylacetylene-terminated polyimide resin is as follows: First, the active hydrogen in cumene hydrogen peroxide will first catalyze the curing system of phenylacetylene-terminated polyimide resin. Trimerization of the phenylacetylene functional group occurs to generate a cross-linked network structure with a polyene or multi-ring structure. Then, under the combined action of active hydrogen cocatalyst, the organic cobalt catalyst and the phenylacetylene functional group form a metal-π bond intermediate, thereby catalyzing the curing reaction of the phenylacetylene-terminated polyimide resin.

The second part is the establishment of low temperature curing process. The curing temperature of the phenylacetylene-terminated polyimide resin is generally above 371°C, and only at this temperature can the properties of the cured product meet the requirements. When the curing temperature is lower than this temperature, the phenylacetylene-terminated polyimide resin is not fully cured and cannot maintain its excellent heat resistance. Still maintaining good properties requires the development of new curing processes. The invention adopts gradient temperature curing to completely cure the phenylacetylene-terminated polyimide resin system, can be applied in many fields requiring low temperature curing, and maintains the excellent performance of the phenylacetylene-terminated polyimide resin.

Example 1:

A preparation method of an efficient catalytic curing phenylacetylene-terminated polyimide resin system, the specific steps are as follows:

A. Preparation of phenylacetylene polyimide resin system

60 parts of phenylethynyl-terminated polyimide and 40 parts of 1,4-dioxane are weighed, and the two are mixed to obtain a phenylethynyl-terminated polyimide resin solution;

B. Mixing of new high-efficiency catalyst and resin system

The new high-efficiency catalyst is composed of cumene hydrogen peroxide and cobalt naphthenate in a mass ratio of 20:80; the new catalyst is mixed with the resin system at room temperature, and a magnetic stirrer is used to continuously stir for 2 hours to ensure that the two are evenly mixed. The mass ratio of resin system to cumene hydroperoxide and cobalt naphthenate is 100:4:1;

C, the establishment of gradient temperature curing process

The mixed resin system and the new high-efficiency compound catalyst were kept in a vacuum oven at a constant temperature of 60 °C for 3 hours to remove most of the solvent in the system, and then kept at a constant temperature of 120 °C for 1 hour to completely remove the solvent, and then cured at a temperature of 240 °C 2h, and finally cured at 300°C for 3h to obtain a fully cured phenylethynyl-terminated polyimide resin; the vacuum oven is a DZF-6000 series vacuum drying oven of Shanghai Yiheng Technology Co., Ltd.

The resin cured product obtained in this example was tested by infrared spectroscopy, and the test results are shown in Figure 1, wherein the first sample is the cured product of the phenylacetylene-terminated polyimide that is completely thermally cured without adding a catalyst, and the second sample is added The product of the cured phenylacetylene-terminated polyimide of the catalyst is obtained. It can be seen from the spectrogram that the catalyst plays a catalytic role in the curing process of the resin, making the phenylacetylene-terminated polyimide at a lower temperature. Amine resins can open carbon-carbon triple bonds for cross-linking and curing.

According to the infrared spectrum test, the structure in the resin casting body can be obtained preliminarily, and the functional groups represented by several infrared spectrum absorption peaks in the figure are shown in Table 1.

Table 1 Infrared absorption peaks corresponding to functional groups

Example 2:

A preparation method of an efficient catalytic curing phenylacetylene-terminated polyimide resin system, the specific steps are as follows:

A. Preparation of compound catalyst and phenylacetylene polyimide resin system

Weigh 70 parts of phenylethynyl-terminated polyimide and 30 parts of 1,4-dioxane, and mix the two to obtain a phenylethynyl-terminated polyimide resin solution;

B. Mixing of new high-efficiency catalyst and resin system

The new high-efficiency catalyst is composed of cumene hydrogen peroxide and cobalt naphthenate in a mass ratio of 20:80. Mix the new catalyst with the resin system at room temperature, and use a magnetic stirrer to stir continuously for 2 hours to ensure that the two are mixed evenly. The mass ratio of the resin system to cumene hydroperoxide and cobalt naphthenate is 100:3:1;

C, the establishment of gradient temperature curing process

The mixed resin system and the new high-efficiency compound catalyst were kept in a vacuum oven at a constant temperature of 60 °C for 3 hours to remove most of the solvent in the system, and then kept at a constant temperature of 120 °C for 1 hour to completely remove the solvent, and then cured at a temperature of 240 °C 2h, and finally cured at 300° C. for 4h to obtain a fully cured phenylethynyl-terminated polyimide resin.

Thermogravimetric analysis (TGA) was performed on the cured resin obtained in this example. The test results are shown in Figure 2. The first sample is a sample powder of a phenylacetylene-terminated polyimide that is completely thermally cured, and the second sample is a phenylacetylene group. For the sample powder of the end-capped polyimide resin cured under the operation of this example, it can be roughly seen from the figure that the thermal decomposition temperature of sample 1 and sample 2 does not change significantly. It can be seen through calculation that 5% of sample 1 is thermally decomposed The temperature is T5%=557.5°C, and the thermal decomposition temperature of the second sample is T5%=538.3°C. It can be seen from this that the curing regime in the operation of this embodiment has little effect on the thermal decomposition temperature of the cured resin product.

Example 3:

A preparation method of an efficient catalytic curing phenylacetylene-terminated polyimide resin system, the specific steps are as follows:

A. Preparation of compound catalyst and phenylacetylene polyimide resin system

80 parts of phenylethynyl-terminated polyimide and 20 parts of 1,4-dioxane were weighed, and the two were mixed to obtain a phenylethynyl-terminated polyimide resin solution;

B. Mixing of new high-efficiency catalyst and resin system

The new high-efficiency catalyst is composed of cumene hydrogen peroxide and cobalt naphthenate in a mass ratio of 20:80. Mix the new catalyst with the resin system at room temperature, and use a magnetic stirrer to stir continuously for 2 hours to ensure that the two are mixed evenly. The mass ratio of the resin system to cumene hydroperoxide and cobalt naphthenate is 100:1:1;

C, the establishment of gradient temperature curing process

The mixed resin system and the new high-efficiency compound catalyst were kept in a vacuum oven at a constant temperature of 60 °C for 3 hours to remove most of the solvent in the system, and then kept at a constant temperature of 120 °C for 1 hour to completely remove the solvent, and then cured at a temperature of 240 °C 2h, and finally cured at a temperature of 300° C. for 3h to obtain a fully cured phenylethynyl-terminated polyimide resin.

Claims (10)

1. A preparation method of a phenylacetylene-terminated polyimide resin system with high-efficiency catalytic curing is characterized by comprising the following steps: the method comprises the following specific steps:

the method comprises the following steps: preparing a compound catalyst and phenylethynyl polyimide resin system:

weighing 60-80 parts of phenylethynyl terminated polyimide resin and 20-40 parts of 1, 4-dioxane, uniformly mixing the phenylethynyl terminated polyimide resin and the phenylethynyl terminated polyimide resin at room temperature to obtain phenylethynyl terminated polyimide resin solution, and adding a compound catalyst into the phenylethynyl terminated polyimide resin solution at room temperature, wherein the compound catalyst is a mixture of cumene hydroperoxide and cobalt naphthenate; the mass ratio of the phenylethynyl terminated polyimide resin solution to the cumene hydroperoxide and the cobalt naphthenate is 100: 1-4: 1; putting the resin glue solution mixed system into a vacuum oven for vacuumizing treatment at room temperature for 1-2 h;

step two: performing gradient curing on the resin glue solution mixed system obtained in the step one: firstly curing at the temperature of 120-140 ℃ for 1h, then curing at the temperature of 240-250 ℃ for 2h, and finally curing at the temperature of 300 ℃ for 3-4 h to obtain the completely cured phenylethynyl terminated polyimide resin.

2. The preparation method of the phenylacetylene capped polyimide resin system with high catalytic curing efficiency according to claim 1, wherein the preparation method comprises the following steps: in the first step, 60 parts of phenylethynyl terminated polyimide resin and 40 parts of 1, 4-dioxane are added; the mass ratio of the resin system to the cumene hydroperoxide and the cobalt naphthenate is 100: 4: 1.

3. the preparation method of the phenylacetylene capped polyimide resin system with high catalytic curing efficiency according to claim 1, wherein the preparation method comprises the following steps: in the second step, the gradient curing system is to cure at 120 ℃ for 1h, then cure at 240 ℃ for 2h, and finally cure at 300 ℃ for 3 h.

4. The preparation method of the low-temperature curing phenylethynyl polyimide resin system catalyzed by the built catalyst according to claim 1 is characterized in that: in the first step, 80 parts of phenylethynyl terminated polyimide resin, 20 parts of 1, 4-dioxane and a resin system, namely cumene hydroperoxide and cobalt naphthenate in a mass ratio of 100: 3: 1.

5. the preparation method of the low-temperature curing phenylethynyl polyimide resin system catalyzed by the built catalyst according to claim 1 is characterized in that: in the second step, the gradient curing system is to cure at 140 ℃ for 1h, then cure at 250 ℃ for 2h, and finally cure at 300 ℃ for 4 h.

6. The preparation method of the low-temperature curing phenylethynyl polyimide resin system catalyzed by the built catalyst according to claim 1 is characterized in that: in the first step, 75 parts of phenylethynyl terminated polyimide resin, 25 parts of 1, 4-dioxane and a resin system, namely cumene hydroperoxide and cobalt naphthenate in a mass ratio of 100: 1: 1.

7. the preparation method of the low-temperature curing phenylethynyl polyimide resin system catalyzed by the built catalyst according to claim 1 is characterized in that: in the second step, the gradient curing system is to cure at 125 ℃ for 1h, then cure at 245 ℃ for 2h, and finally cure at 300 ℃ for 3 h.

8. The preparation method of the low-temperature curing phenylethynyl polyimide resin system catalyzed by the built catalyst according to claim 1 is characterized in that: in the first step, 75 parts of phenylethynyl terminated polyimide resin, 25 parts of 1, 4-dioxane and a resin system, namely cumene hydroperoxide and cobalt naphthenate in a mass ratio of 100: 4: 1.

9. the preparation method of the low-temperature curing phenylethynyl polyimide resin system catalyzed by the built catalyst according to claim 1 is characterized in that: in the second step, the gradient curing system is to cure for 1 hour at the temperature of 130 ℃, then cure for 2 hours at the temperature of 245 ℃, and finally cure for 3 hours at the temperature of 300 ℃.

10. The preparation method of the low-temperature curing phenylethynyl polyimide resin system catalyzed by the built catalyst according to claim 1 is characterized in that: in the first step, the resin glue solution mixed system is placed into a vacuum oven for vacuum pumping treatment at room temperature, and the treatment time is 1.5 h.

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