KR102264814B1 - Manufacturing method of porous polyimide using high internal phase emulsion - Google Patents

Abstract

The present invention relates to a method for producing a porous polyimide using a high internal phase emulsion, and a polyamic acid salt mixing step of mixing a polyamic acid salt in an amine aqueous solution, and a polyimide powder added to the mixture prepared through the polyamic acid salt mixing step and dispersing the polyimide dispersion step, an ultrasonic irradiation step of irradiating ultrasonic waves to the dispersion prepared through the polyimide dispersion step, and mixing and homogenizing the inner phase forming material in the dispersion irradiated with ultrasonic waves through the ultrasonic irradiation step to obtain a high internal phase A high inner phase emulsion production step of preparing an emulsion, a freeze drying step of freeze-drying the high inner phase emulsion prepared through the high inner phase emulsion production step, and an imidization step of heating the lyophilized high inner phase emulsion through the freeze-drying step is done
Since the porous polyimide produced through the above process is manufactured using the high internal phase emulsion as a template, it has a high porosity and excellent heat resistance, thereby exhibiting effects applicable to various technical fields and high temperature environments.

Description

Manufacturing method of porous polyimide using high internal phase emulsion {MANUFACTURING METHOD OF POROUS POLYIMIDE USING HIGH INTERNAL PHASE EMULSION}

The present invention relates to a method for manufacturing a porous polyimide using a high internal phase emulsion, and more particularly, because it is manufactured using a high internal phase emulsion as a template, it has a high porosity and excellent heat resistance, so it can be applied to various technical fields and high temperature environments. It relates to a method for producing a porous polyimide.

Porous materials are widely used for gas storage, separation membranes, catalysts, and insulating materials. Among them, the porous polymer has a variety of manufacturing methods and easy processability, and has the advantage of being able to introduce various chemical structures and pore structures. Among the methods for preparing porous polymers, a method using a high internal phase emulsion (HIPE) as a template is attracting attention in that it can produce a porous polymer exhibiting high porosity and permeability. HIPE refers to an emulsion in which the internal phase accounts for more than 74% of the total emulsion volume. PolyHIPE refers to a porous polymer manufactured by using HIPE as a template. A typical manufacturing method of PolyHIPE is a method of radical polymerization of a monomer dissolved in an internal phase and/or an external phase after HIPE is prepared. Therefore, the skeleton of PolyHIPE is made of polystyrene, polyacrylate or polymethacrylate. As a stabilizer for HIPE, molecular surfactants, solid particles, or a combination of surfactants and solid particles are generally used.

PolyHIPE generally has two types of pores, a void formed by the frame of the emulsion droplet, and a window that is smaller and connects the voids. Due to this unique pore structure, polyHIPE exhibits high permeability and is being researched and developed as an adsorbent, a separation membrane, a catalyst, and a tissue engineering material.

As shown above, the method for manufacturing HIPE using a surfactant requires a large amount of surfactant to account for up to 30% by weight of the external phase, and an additional process and cost for removing the surfactant component from PolyHIPE are generated. There was a problem.

On the other hand, Pickering HIPE is an emulsion prepared using solid particles as a stabilizer, and has excellent stability because solid particles are strongly adsorbed to the oil-water interface. Compared to conventional HIPE stabilized with a surfactant, HIPE with high resistance to phase has the advantage that it can be stabilized with a relatively small amount of particles, and the use of solid particles shows the advantage of adding physical properties to polyHIPE.

Korean Patent Registration No. 10-1981853 (2019.05.17) Korean Patent Publication No. 10-2019-0054923 (2019.05.22)

An object of the present invention is to provide a method for producing a porous polyimide that is applicable to various technical fields and high-temperature environments due to high porosity and excellent heat resistance since it is prepared using a high internal phase emulsion as a template.

An object of the present invention is a polyimide mixing step of mixing a poly(amic acid) salt with an amine aqueous solution, and injecting and dispersing a polyimide powder into a mixture prepared through the polyamic acid mixing step. Dispersing step, ultrasonic irradiation step of irradiating ultrasonic waves to the dispersion prepared through the polyimide dispersing step, mixing and homogenizing the inner phase forming material in the dispersion irradiated with ultrasonic waves through the ultrasonic irradiation step to prepare a high internal phase emulsion An inner phase emulsion production step, a freeze-drying step of freeze-drying the high inner phase emulsion prepared through the high inner phase emulsion production step, and an imidization step of heating the freeze-dried high inner phase emulsion through the freeze-drying step It is achieved by providing a method for producing a porous polyimide using a high internal phase emulsion.

According to a preferred feature of the present invention, the amine aqueous solution is assumed to have a volume concentration of 1 to 3%.

According to a more preferred feature of the present invention, the amine is triethylamine.

According to a more preferred feature of the present invention, the polyamic acid salt mixing step is made by mixing 1 to 10 parts by weight of the polyamic acid salt in 100 parts by weight of the triethylamine aqueous solution.

According to an even more preferred feature of the present invention, the polyimide dispersion step is made by adding 1 to 10 parts by weight of the polyimide powder to 100 parts by weight of the mixture prepared through the polyamic acid salt mixing step.

According to an even more preferred feature of the present invention, the polyimide powder is prepared by adding a dianhydride compound and a diamine compound to distilled water, refluxing, adding a catalyst and a dehydrating agent, and refluxing.

According to an even more preferred feature of the present invention, the ultrasonic irradiation step is made by irradiating ultrasonic waves having a frequency of 20 to 100 kHz for 10 to 120 minutes.

According to an even more preferred feature of the present invention, in the high internal phase emulsion manufacturing step, the dispersion liquid irradiated with ultrasonic waves through the ultrasonic irradiation step and the internal phase forming material are mixed in a volume ratio of 30:70 to 10:90, and 15000 using a homogenizer It shall be made by homogenizing at a speed of 25000 rpm.

According to an even more preferred feature of the present invention, the inner phase forming material is made of cyclohexane.

According to an even more preferred feature of the present invention, in the freeze-drying step, the high-inner phase emulsion prepared through the high-inner phase emulsion production step is immersed in liquid nitrogen to freeze, then put into a freeze dryer and heated at -60 to -40°C. It shall be made by drying at temperature.

According to an even more preferred feature of the present invention, the imidization step shall consist of heating the high internal phase emulsion lyophilized through the freeze-drying step from a temperature of 50°C to 450°C.

According to an even more preferred feature of the present invention, the imidization step is performed at a temperature of 80 to 120° C. for 30 minutes to 2 hours, 180 to 220° C. for 30 minutes to 2 hours, and at a temperature of 280 to 320° C. for 30 minutes. to 2 hours and a process of heating at a temperature of 380 to 420° C. for 30 minutes to 2 hours.

According to an even more preferred feature of the present invention, the imidization step is a process of heating at a temperature of 100° C. for 1 hour, at a temperature of 200° C. for 1 hour, at a temperature of 300° C. for 1 hour, and at a temperature of 400° C. for 1 hour. shall be made with

In addition, the object of the present invention can also be achieved by providing a porous polyimide, characterized in that it is prepared by the method for producing a porous polyimide using the high internal phase emulsion.

According to a preferred feature of the present invention, the porous polyimide has a porosity of 70% or more and a thermal decomposition temperature of 500° C. or more.

The method for producing a porous polyimide using the high internal phase emulsion according to the present invention is prepared by using the high internal phase emulsion as a template, so it has a high porosity and excellent heat resistance, thereby providing a porous polyimide applicable to various technical fields and high temperature environments. shows excellent effect.

1 is a photograph showing the external appearance of the high internal phase emulsion prepared through Preparation Example 1 of the present invention.
2 is a graph showing the measurement of the infrared absorption spectrum of the porous polyimide prepared in Example 1 of the present invention.
3 is a photograph showing the polyimide prepared in Comparative Example 1 and Examples 2 to 4 taken by a scanning electron microscope.

Hereinafter, a preferred embodiment of the present invention and the physical properties of each component will be described in detail, which is intended to describe in detail enough that a person of ordinary skill in the art to which the present invention pertains can easily carry out the invention, This does not mean that the technical spirit and scope of the present invention is limited.

The method for producing a porous polyimide using a high internal phase emulsion according to the present invention includes a polyamic acid salt mixing step of mixing a polyamic acid salt in an amine aqueous solution, and a polyimide powder added to the mixture prepared through the polyamic acid salt mixing step and dispersed. a polyimide dispersing step, an ultrasonic irradiation step of irradiating ultrasonic waves to the dispersion prepared through the polyimide dispersing step, and mixing and homogenizing the inner phase forming material in the dispersion irradiated with ultrasonic waves through the ultrasonic irradiation step to obtain a high internal phase emulsion It consists of a high-inner-phase emulsion preparation step to prepare, a freeze-drying step of freeze-drying the high-inner phase emulsion prepared through the high-inner phase emulsion production step, and an imidization step of heating the lyophilized high inner phase emulsion through the freeze-drying step.

The polyamic acid salt mixing step is a step of mixing the polyamic acid salt with the amine aqueous solution, and is made by mixing 1 to 10 parts by weight of the polyamic acid salt with 100 parts by weight of the amine aqueous solution. The polyamic acid salt acts as a stabilizer and has a high internal phase It serves to enable the emulsion to be provided.

As described above, if the polyamic acid salt is not contained and the process for preparing the porous polyimide is performed using only the polyimide powder as a stabilizer, it becomes difficult to prepare the high internal phase emulsion.

At this time, it is preferable to use the amine aqueous solution having a volume concentration of 1 to 3%, and it is more preferable to use triethylamine as the amine.

When the content of the polyamic acid salt is less than 1 part by weight, the above effect is insignificant, and when the content of the polyamic acid salt exceeds 10 parts by weight, the viscosity of the mixture increases excessively, making it difficult to prepare an emulsion.

The polyimide dispersing step is a step of injecting and dispersing the polyimide powder into the mixture prepared through the polyamic acid salt mixing step, and 1 to 10 parts by weight of the polyimide powder in 100 parts by weight of the polyamic acid salt mixing step. It is made by adding parts by weight, and it is more preferable to add 2 to 8 parts by weight of polyimide powder.

As described above, the polyimide powder acts as a stabilizer together with the polyamic acid salt to provide a high internal phase emulsion. Instead of adding the polyimide powder, only the polyamic acid salt is used as a stabilizer. When the process of manufacturing the mid is progressed, the pore structure may be collapsed in the process of freezing and drying performed in the freeze-drying step.

In addition, when the content of the polyimide powder is less than 1 part by weight, the above effect is insignificant, and when the content of the polyimide powder exceeds 10 parts by weight, the polyimide powder is not evenly dispersed in the mixture.

The polyimide powder is prepared by adding a dianhydride compound and a diamine compound to distilled water, refluxing, adding a catalyst and a dehydrating agent, and refluxing, more specifically, dianhydride and diaphragm in a flask substituted with nitrogen gas. It can be synthesized by dispersing min in distilled water as a dispersion medium, adding a catalyst and a dehydrating agent, and reacting at about 100° C. for about 24 hours under reflux. After filtering the reaction mixture, it is washed with distilled water, acetone, or methanol. It can be prepared by vacuum drying the obtained solid.

In addition, the polyamic acid salt mixed in the polyamic acid salt mixing step is prepared by reacting a dianhydride compound and a diamine compound in an organic solvent to prepare a polyamic acid, and then neutralizing the polyamic acid by adding a tertiary amine compound.

The dianhydride compound used in the preparation of the polyimide powder and the polyamic acid salt may have the following chemical structure, but is not limited thereto.

In addition, the polyimide powder and the diamine compound used in the manufacturing process of the polyamic acid salt may have the following chemical structure, but are not limited thereto.

The ultrasonic irradiation step is a step of irradiating ultrasonic waves to the dispersion prepared through the polyimide dispersing step. The ultrasonic wave having a frequency of 20 to 100 kHz is irradiated to the dispersion prepared through the polyimide dispersing step for 10 to 120 minutes. is done

After the ultrasonic irradiation step made through the above process, the average diameter of the polyimide powder contained in the dispersion is adjusted to 10nm to 20㎛.

If the average diameter of the polyimide powder contained in the dispersion is not adjusted as in the above range, the polyimide particles may not be uniformly dispersed in the continuous phase, which may cause a problem in that the high internal phase emulsion is not stabilized. Therefore, adjusting the average diameter of the polyimide powder by irradiating ultrasonic waves as described above is effective in suppressing phase separation and stabilizing the dispersed phase.

The high internal phase emulsion manufacturing step is a step of preparing a high internal phase emulsion by mixing and homogenizing the internal phase forming material with the dispersion irradiated with ultrasonic waves through the ultrasonic irradiation step, and the dispersion liquid irradiated with ultrasonic waves and the inner phase emulsion through the ultrasonic irradiation step. The flotation forming material is mixed at 30:70 to 10:90 and homogenized for 5 to 15 minutes at a speed of 15000 to 25000 rpm using a homogenizer. In this case, the inner phase forming material is preferably made of cyclohexane.

The high internal phase emulsion prepared through the above process acts as a template in the process of manufacturing the porous polyimide. As described above, the porous polyimide prepared using the high internal phase emulsion as a template has a high porosity and exhibits excellent heat resistance.

The freeze-drying step is a step of freeze-drying the high-inner-phase emulsion prepared through the high-inner-phase emulsion production step, and more specifically, the high-inner phase emulsion prepared through the high-inner phase emulsion production step is prepared in a mold with a predetermined size. After inserting into the groove, the mold is immersed in liquid nitrogen to freeze, then separated from the mold and put into a freeze dryer to dry at a temperature of -60 to -40°C. At this time, in the process of being frozen through the above process and then put into the freeze dryer, the high internal phase emulsion may be separated from the mold and put into the freeze dryer or may be put into the freeze dryer while attached to the mold.

In the freeze-drying step made under the above conditions, since the polyamic acid salt and the polyimide powder in the high internal phase emulsion act as stabilizers, the pore structure is not collapsed and a certain shape can be maintained.

The imidization step is a step of heating the high inner phase emulsion freeze-dried through the freeze-drying step to imidize, and heating the freeze-dried high inner phase emulsion through the freeze-drying step from a temperature of 50° C. to 450° C. It consists of a process of, at a temperature of 80 to 120 ℃ 30 minutes to 2 hours, 180 to 220 ℃ 30 minutes to 2 hours, 280 to 320 ℃ 30 minutes to 2 hours and 380 to 420 ℃ temperature of It is preferable that the process consists of heating at a temperature for 30 minutes to 2 hours.

After the imidization step comprising the above process, a porous polyimide having a high porosity and excellent heat resistance is provided.

Hereinafter, the method for preparing a porous polyimide using the high internal phase emulsion according to the present invention and the physical properties of the porous polyimide prepared through the manufacturing method will be described with reference to examples.

<Preparation Example 1> Preparation of high internal phase emulsion

4 parts by weight of polyamic acid salt was added to 100 parts by weight of an aqueous triethylamine solution (volume concentration of 2%) and dissolved to prepare a mixture, and 5 parts by weight of polyimide powder was mixed and dispersed in 100 parts by weight of the mixture to prepare a dispersion, The dispersion was irradiated with ultrasonic waves (20 kHz) for 30 minutes, and the ultrasonically irradiated dispersion and cyclohexane were mixed in a volume ratio of 20:80, and then homogenized for 10 minutes at a speed of 20,000 rpm using a homogenizer to obtain a high internal phase emulsion. was prepared.

The appearance of the high internal phase emulsion prepared in Preparation Example 1 was photographed and shown in FIG. 1 below.

<Preparation Example 2> Preparation of high internal phase emulsion

The same procedure as in Preparation Example 1 was performed, except that 6 parts by weight of polyamic acid salt and 1 part by weight of polyimide powder were used to prepare a high internal phase emulsion.

<Preparation Example 3> Preparation of high internal phase emulsion

The same procedure as in Preparation Example 1 was performed, except that 6 parts by weight of polyamic acid salt and 3 parts by weight of polyimide powder were used to prepare a high internal phase emulsion.

<Preparation Example 4> Preparation of high internal phase emulsion

Proceeded in the same manner as in Preparation Example 1, but using 6 parts by weight of polyamic acid salt and 5 parts by weight of polyimide powder, a high internal phase emulsion was prepared.

<Preparation Example 5> Preparation of high internal phase emulsion

The same procedure as in Preparation Example 1 was performed, except that 6 parts by weight of polyamic acid salt and 10 parts by weight of polyimide powder were used to prepare a high internal phase emulsion.

<Preparation Example 6> Preparation of high internal phase emulsion

Proceeded in the same manner as in Preparation Example 1, but using 2 parts by weight of polyamic acid salt and 5 parts by weight of polyimide powder, a high internal phase emulsion was prepared.

<Preparation Example 7> Preparation of high internal phase emulsion

Proceeded in the same manner as in Preparation Example 1, but using 8 parts by weight of polyamic acid salt and 5 parts by weight of polyimide powder, a high internal phase emulsion was prepared.

<Preparation Example 8> Preparation of high internal phase emulsion

The same procedure as in Preparation Example 1 was performed, except that 6 parts by weight of polyamic acid salt and 5 parts by weight of polyimide powder were used, and cyclohexane was mixed at 75% by volume to prepare a high internal phase emulsion.

<Preparation Example 9> Preparation of high internal phase emulsion

The same procedure as in Preparation Example 1 was performed, except that 6 parts by weight of polyamic acid salt and 5 parts by weight of polyimide powder were used, and cyclohexane was mixed at 85% by volume to prepare a high internal phase emulsion.

<Example 1>

The high internal phase emulsion prepared in Preparation Example 1 was put into a groove of 20 mm wide × 20 mm long × 20 mm deep provided in a mold, and the mold was immersed in liquid nitrogen to freeze, and then the frozen high internal phase emulsion was removed from the mold. After separation, put in a freeze dryer, dried at a temperature of -50 °C, heated at a temperature of 100 °C for 1 hour, heated to a temperature of 200 °C, heated for 1 hour, and then heated to a temperature of 300 °C for 1 hour A porous polyimide was prepared by imidization by heating for 1 hour after heating for 1 hour after heating to a temperature of 400 °C.

<Example 2>

A porous polyimide was prepared in the same manner as in Example 1, except that the high internal phase emulsion prepared in Preparation Example 2 was used.

<Example 3>

A porous polyimide was prepared in the same manner as in Example 1 except that the high internal phase emulsion prepared in Preparation Example 3 was used.

<Example 4>

A porous polyimide was prepared in the same manner as in Example 1, except that the high internal phase emulsion prepared in Preparation Example 4 was used.

<Example 5>

A porous polyimide was prepared in the same manner as in Example 1, except that the high internal phase emulsion prepared in Preparation Example 5 was used.

<Example 6>

A porous polyimide was prepared in the same manner as in Example 1 except that the high internal phase emulsion prepared in Preparation Example 6 was used.

<Example 7>

A porous polyimide was prepared in the same manner as in Example 1, except that the high internal phase emulsion prepared in Preparation Example 7 was used.

<Example 8>

A porous polyimide was prepared in the same manner as in Example 1, except that the high internal phase emulsion prepared in Preparation Example 8 was used.

<Example 9>

A porous polyimide was prepared in the same manner as in Example 1 except that the high internal phase emulsion prepared in Preparation Example 9 was used.

<Comparative Example 1>

6 parts by weight of polyamic acid salt was added to 100 parts by weight of triethylamine aqueous solution (volume concentration 2%) and dissolved to prepare a mixture, and ultrasonic wave (20 kHz) was irradiated to the mixture for 30 minutes, and the dispersion solution irradiated with ultrasonic waves and a cycle After mixing hexane in a volume ratio of 20:80, homogenizing for 10 minutes at a speed of 20,000 rpm using a homogenizer to prepare an emulsion, the emulsion was put into a groove of 20 mm in width × 20 mm in length × 20 mm in depth provided in the mold After freezing the mold by immersing it in liquid nitrogen, the frozen emulsion is separated from the mold, put into a freeze dryer, dried at a temperature of -50 °C, and then heated at a temperature of 100 °C for 1 hour, and a temperature of 200 °C Polyimide was prepared by imidization by heating for 1 hour after heating to a temperature of 300 °C, heating for 1 hour after raising the temperature to 300 °C, and heating for 1 hour after raising the temperature to 400 °C.

The infrared absorption spectrum of the porous polyimide prepared in Example 1 was measured and shown in FIG. 2 below.

As shown in FIG. 2 below, asymmetric imide C = O stretching is ^{1777 cm -1, symmetric imide C =} O stretching the 1718cm ^-1, imide CN stretching is being observed at 1384 cm ^-1 shows that the porous structure consisting of a polyimide can

In addition, the porosity and thermal decomposition temperature of the porous polyimides prepared in Examples 1 to 9 were measured and shown in Table 1 below.

(However, the porosity was analyzed using AutoPore IV 9520 equipment, and the thermal decomposition temperature was measured by measuring the _{T 10 value, which is the temperature at which 10 wt% of the sample weight is decomposed.)}

<Table 1>

As shown in Table 1, it can be seen that the porous polyimides prepared in Examples 1 to 9 of the present invention have excellent heat resistance because the porosity is high and the thermal decomposition temperature exceeds 500°C.

In addition, the polyimides prepared in Comparative Example 1 and Examples 2 to 4 were photographed with a scanning electron microscope and shown in FIG. 3 below. {(a) Comparative Example 1, (b) Example 2, ( c) Example 3, (d) Example 4}

As shown in FIG. 3 below, it can be seen that in Comparative Example 1 in which the polyimide powder was not contained, the pore structure was collapsed.

Therefore, the method for manufacturing a porous polyimide using the high internal phase emulsion according to the present invention is manufactured using the high internal phase emulsion as a template, and thus has a high porosity and excellent heat resistance. to provide.

Claims (15)

A polyamic acid salt mixing step of mixing the polyamic acid salt in the amine aqueous solution;
a polyimide dispersion step of injecting and dispersing polyimide powder into the mixture prepared through the polyamic acid salt mixing step;
an ultrasonic irradiation step of irradiating ultrasonic waves to the dispersion prepared through the polyimide dispersion step;
a high internal phase emulsion manufacturing step of mixing and homogenizing an internal phase forming material in the dispersion liquid irradiated with ultrasonic waves through the ultrasonic irradiation step to prepare a high internal phase emulsion;
a freeze-drying step of freeze-drying the high-inner-phase emulsion prepared through the high-inner-phase emulsion preparation step; and
An imidization step of heating the lyophilized high internal phase emulsion through the freeze-drying step;
The high internal phase emulsion manufacturing step is performed by mixing the dispersion liquid irradiated with ultrasonic waves through the ultrasonic irradiation step and the internal phase forming material in a volume ratio of 30:70 to 10:90 and homogenizing at a speed of 15000 to 25000 rpm using a homogenizer A method for producing a porous polyimide using a high internal phase emulsion, characterized in that
The method according to claim 1,
The method for producing a porous polyimide using a high internal phase emulsion, characterized in that the amine aqueous solution has a volume concentration of 1 to 3%.
3. The method according to claim 2,
The method for producing a porous polyimide using a high internal phase emulsion, characterized in that the amine is triethylamine.
The method according to claim 1,
The polyamic acid salt mixing step is a method for producing a porous polyimide using a high internal phase emulsion, characterized in that the polyamic acid salt 1 to 10 parts by weight of 100 parts by weight of the triethylamine aqueous solution is mixed.
The method according to claim 1,
The polyimide dispersing step is a method for producing a porous polyimide using a high internal phase emulsion, characterized in that 1 to 10 parts by weight of the polyimide powder is added to 100 parts by weight of the mixture prepared through the polyamic acid salt mixing step.
6. The method of claim 5,
The method for producing a porous polyimide using a high internal phase emulsion, characterized in that the polyimide powder is prepared by adding a dianhydride compound and a diamine compound to distilled water, refluxing, adding a catalyst and a dehydrating agent, and refluxing.
The method according to claim 1,
The ultrasonic irradiation step is a method for producing a porous polyimide using a high internal phase emulsion, characterized in that the ultrasonic wave of a frequency of 20 to 100 kHz is irradiated for 10 to 120 minutes.
delete The method according to claim 1,
The method for producing a porous polyimide using a high internal phase emulsion, characterized in that the inner phase forming material consists of cyclohexane.
The method according to claim 1,
The freeze-drying step is performed by immersing the high-inner-phase emulsion prepared through the high-inner-phase emulsion manufacturing step in liquid nitrogen to freeze it, then putting it in a freeze dryer and drying it at a temperature of -60 to -40°C. A method for producing a porous polyimide using an inner phase emulsion.
The method according to claim 1,
The imidization step is a method for producing a porous polyimide using a high inner phase emulsion, characterized in that it comprises a process of heating the lyophilized high internal phase emulsion through the freeze-drying step to increase the temperature from 50 °C to 450 °C.
12. The method of claim 11,
The imidization step is performed at a temperature of 80 to 120 °C for 30 minutes to 2 hours, 180 to 220 °C for 30 minutes to 2 hours, 280 to 320 °C for 30 minutes to 2 hours, and a temperature of 380 to 420 °C. A method for producing a porous polyimide using a high internal phase emulsion, characterized in that it comprises a process of heating for 30 minutes to 2 hours.
13. The method of claim 12,
The imidization step is a high internal phase emulsion, characterized in that it consists of heating at a temperature of 100 ° C. for 1 hour, at a temperature of 200 ° C. for 1 hour, at a temperature of 300 ° C. for 1 hour, and at a temperature of 400 ° C. for 1 hour. A method for producing a porous polyimide using
A porous polyimide produced by the method according to any one of claims 1 to 7 and 9 to 13.
15. The method of claim 14,
The porous polyimide has a porosity of 70% or more and a thermal decomposition temperature of 500° C. or more.

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