KR20170051156A - Carbon molecular sieve membranes based on fluorine-containing polymer/polysilsesquioxane blending precursors and method for fabricating the same - Google Patents

Abstract

The present invention provides a fluorine-containing polymer matrix and a composition for preparing a carbon molecular sieve separation membrane comprising polysilsesquioxane. The composition exhibits high selectivity and separation performance according to target gas to be separated through controlling a mixing ratio of the fluorine-containing polymer matrix and polysilsesquioxane. Therefore, it is possible to effectively separate gases having small difference in particle sizes, which have been difficult to be separated using conventional polymer separation membranes.

Description

TECHNICAL FIELD The present invention relates to a carbon molecular sieve separator based on a fluorine-containing polymer / polysilsesquioxane mixture, and a method for manufacturing the same.

The present invention relates to a carbon molecular sieve separator having excellent gas permeability and selectivity.

In the petrochemical industry, ethylene / ethane or propylene / propane is a very important compound, forming a very large market size around the world. These olefin / paraffin separations have been separated primarily by cryogenic distillation, but they have the disadvantage of consuming a lot of energy and are attempting to replace them with energy efficient membrane technology. In addition, CMS (Carbon Molecular Sieve) using a carbon molecular sieve, which is a separation membrane having excellent performance in separating gas molecules that are difficult to separate due to a large difference in molecular size such as O ₂ / N ₂ or CO ₂ / CH ₄ , There is an increasing need to develop gas separation membranes.

The excellent gas separation performance of the CMS gas separation membrane is based on a combination of micropores (6-20 Å) having a very high permeability and micropores (<6 Å) having a molecular sieve function. Various parameters such as polymer precursor, pyrolysis temperature, heating rate, pyrolysis time and pyrolysis conditions affect the structure of the CMS separator. In general, the higher the free volume fraction of the polymer precursor, the better the separation performance of the CMS. Considering the treatment conditions, the higher the pyrolysis temperature, the smaller the micropores and ultrafine pores are formed, and the permeability decreases and the selectivity tends to increase. Also, as the heating rate increases, the permeability increases and the selectivity decreases, which is presumed to be closely related to the formation rate of the byproducts or the calcination of the pores. The longer the pyrolysis time, the higher the selectivity but the lower the permeability (see U.S. Patent No. 8,911,534). In particular, pyrolysis temperatures and polymer precursors play an important role in determining the performance of CMS membranes. The Koros group of Georgia Tech, USA, proved that the separation performance of CMS membranes can be determined by controlling the oxygen content during pyrolysis (Kiyono M, Williams PJ, and Koros WJ Journal of Membrane Science 2010; 359 (1-2): 2-10, U.S. Pat. No. 8,486,179).

U.S. Pat. No. 8,486,179

Kiyono M, Williams PJ, and Koros WJ. Journal of Membrane Science 2010; 359 (1-2): 2-10. Rungta M, Xu LR, and Koros WJ. Carbon 2015; 85: 429-442.

An object of the present invention is to provide a composition for producing a carbon molecular sieve separator having excellent gas permeability and selectivity. The present invention also provides a carbon molecular sieve separator prepared by using the composition, a method for producing the same, and a gas separation method.

In order to achieve the above object, the present invention provides, in one aspect, a composition for preparing a carbon molecular sieve (CMS) comprising a fluorine-containing polymer matrix and polysilsesquioxane.

In another aspect, the present invention provides a carbon molecular sieve separator comprising a carbide of the composition for preparing a carbon molecular sieve separator.

According to another aspect of the present invention, there is provided a process for producing a polymer membrane, comprising the steps of: dissolving a polymer matrix containing fluorine and a composition containing polysilsesquioxane into an organic solvent; And a step of carbonizing the polymer separator, and a method of separating the carbon molecular sieve separator.

The composition for preparing a carbon molecular sieve separator according to the present invention comprises a fluorine-containing polymer matrix having a high free volume and a glass transition temperature as an organic polymer and mixing the polymer matrix with polysilsesquioxane, whereby the polysilsesquioxane They are dispersed homogeneously at the molecular level of the polymer matrix and the membrane. Further, the present invention can control the silicon etching phenomenon of the polysilsesquioxane through the selection of kinds of fluorine-containing polymer matrix and polysilsesquioxane, control of mixing ratio or temperature control of carbonization, Pore size can be adjusted. Further, the present invention can induce additional ultrafine pores by using the silicon etching phenomenon, and can improve the selectivity of the carbon molecular sieve separator even at a relatively low temperature. Accordingly, the present invention provides a novel method for controlling the size and distribution of micropores and micropores, thereby enabling high selectivity and separation performance according to a target gas to be separated. Therefore, it is possible to improve the separation performance of the conventional polymer separator and particularly to improve the separation performance of oxygen (O ₂ ) / nitrogen (N ₂ ), carbon dioxide (CO ₂ ) / carbon tetrachloride (CH ₄ ) propylene (C ₃ H ₆ ) ₃ H ₈ ) and ethylene (C ₂ H ₄ ) / ethane (C ₂ H ₆ ).

FIG. 1 is a graph showing the relationship between the concentration of fluorine-containing polymer matrix and the molecular weight of 6FDA-DAM: DABA (3: 2) (A), LPMA64 (B), LPG64 D). &Lt; / RTI &gt;
2 is a graph showing the results of ¹ H NMR analysis of ladder-type silsesquioxane (LPPyr64) containing pyridine.
3 is a graph showing the results of ²⁹ Si NMR analysis of ladder-type silsesquioxane (LPPyr64) containing pyridine.
4 is a view showing a pyrolysis apparatus setup for carbonization of a polymer membrane.
5 is a photograph of a carbon molecular sieve separator prepared by using 6FDA-DAM: DABA (3: 2) / LPSQ (90/10 wt / wt) as a precursor.
6 is an SEM image of a polymer membrane prepared from a composition for preparing a carbon molecular sieve separation membrane. The left photographs are low-resolution images, and the right photographs are high-resolution images. DAF: DABA (3: 2) / LPMA64 (90/10 wt / wt), (B-1) and (B- (90/10 wt / wt), 6FDA-DAM: DABA (3: 2) / LPPyr64 (90/10 wt / wt), (C-1) and (C-2).
7A and 7B are graphs showing the results of measurement of the molecular weight distribution of 6FDA-DAM: DABA (3: 2) (PI), 6FDA-DAM: DABA (3: 2) / 20 wt / wt), 6FDA-DAM: DABA (3: 2) (PI) / LPPyr64 (90/10 wt / wt), 6FDA- IR spectrum of 6FDA-DAM: DABA (3: 2) (PI) / LPMA64 (90/10 wt / wt)
FIG. 8 shows the chemical structure of the ladder-type polysilsesquioxane according to the organic functional group through the FT-IR.
FIG. 9 is a graph showing the results of the experiments of 6FDA-DAM: DABA (3: 2) (PI: Comparative Example 1), PI / LPPyr64 (90/10 wt / (Example 2) and LPPyr 64 (Comparative Example 2).
10 is a graph showing the WAXD pattern of 6FDA-DAM: DABA (3: 2) (PI), PI / LPPyr64 (90/10 wt / wt), PI / LPPyr64 (80/20 wt / Fig.
FIG. 11 is a graph showing the results of measurement of the carbon molecular sieve separator (CMS) of 6FDA-DAM: DABA (3: 2) (PI), PI / LPPyr64 (90/10 wt / wt), PI / LPPyr64 (80/20 wt / Fig.
12 is a graph showing the results of 29 Si NMR analysis of carbon molecular sieve membranes obtained by carbonizing PI / LPPyr 64 (90/10 wt / wt), PI / LPPyr 64 (80/20 wt / wt) and LPPyr 64.
13 is a STEM image of a carbon molecular sieve separator (CMS) obtained by carbonizing (PI), PI / LPPyr 64 (90/10 wt / wt) and PI / LPPyr 64 (80/20 wt / Fig.
FIG. 14 is a graph showing the relationship between the concentration of 6FDA-DAM and DABA (3: 2) (LPSQ concentration 0%), PI / LPPyr64 (90/10 wt / (A) CO ₂ / N ₂ , (B) CO ₂ / CH ₄ , (C) C ₃ H ₆ / C ₃ H ₈ of the carbon molecular sieve separator (CMS) Respectively. Fig.
FIG. 15 is a graph showing the relationship between the concentration of 6FDA-DAM and DABA (3: 2) (LPSQ concentration 0%), PI / LPPyr64 (90/10 wt / Propane / propane (C ₃ H ₆ / C ₃ H ₈ ) selectivity against the propylene (C ₃ H ₆ ) permeability of the polymer upper bound and CMS upper bound of LPSQ concentration 20% .
16 is a graph showing pore distribution according to the content of LPPyr 64 in a carbon molecular sieve separator (CMS) formed by the same pyrolysis conditions.
17 shows the C ₃ H ₆ / C ₃ H ₈ separation performance (C ₃ H) of the corresponding carbon molecular sieve separating membrane (CMS) using the precursor having different compatibility with the polymer according to the organic functional group of polysilsesquioxane ₆ transmittance (a) and C ₃ H ₆ / C ₃ H ₈ selectivity (b)).

Hereinafter, the present invention will be described in detail.

One embodiment of the present invention is a fluorine-containing polymer matrix; And a polysilsesquioxane (PSQ). The present invention also provides a composition for forming a carbon molecular sieve separator (CMS).

The composition according to one embodiment may include a ladder-structured polysilsesquioxane (LPSQ) represented by the following formula (1).

[Chemical Formula 1]

R ₁ , R ₂ and R ₃ are each independently selected from the group consisting of aromatic phenyl, heteroaromatic phenyl, aliphatic alkyl, cyclic aliphatic alkyl, vinyl, aryl, methacrylate, acrylate, Functional group, and n is an integer selected from 1 to 10,000.

In one embodiment, the polysilsesquioxane is selected from the group consisting of ladder-type poly (phenyl-co-methacryloxypropyl) silsesquioxane, ladder- (Ladder-structured poly (phenyl-co-glycidoxypropyl) silsesquioxane) and ladder-type poly (phenyl-co-pyridylethyl) silsesquioxane -pyridylethyl) silsesquioxane).

In one embodiment, the molar ratio of R _{1 to} R ₂ may be 0.1: 99.9 to 99.9: 0.1 in terms of the copolymer of organic functional groups of the polysilsesquioxane. Specifically, the R ₁ : R ₂ may be 10:90 to 90:10, 20:80 to 80:20, 30:70 to 70:30, 50:50 to 70:30, and 55:45 to 65:35. , And more specifically about 6: 4. In one embodiment, the number average molecular weight of the polysilsesquioxane may be 10 ² to 10 ⁸ , specifically 10 ³ to 10 ⁷ or 10 ⁴ to 10 ⁶ .

Further, the fluorine-containing polymer matrix of the composition according to an embodiment of the present invention may include, for example, a 6-FDA-based polyimide (2,2-bis (3,4-carboxyphenyl) hexafluoropropane dianhydride based polyimide).

(2)

In Formula 2, R is a C1-C20 aliphatic alkyl with or without F; Alicyclic alkyl including monocyclic ring, dicyclic ring, heterocyclic ring, or multicyclic; Or an aromatic ring.

More specifically, the 6-FDA polyimide includes 6FDA-DAM (diamino-mesitylene), 6FDA-mPDA (m-phenylenediamine), 6FDA-DABA (diaminobenzoic acid), 6FDA- BPDA (1: 1) -DETDA, 6FDA-1,5 ND: ODA (1: 1), 6FDA-DETDA: DABA (3: 2), 6FDA- DAM: mPDA (3: 2), and 6FDA-mPDA: DABA (3: 2).

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a fluorine-containing polymer matrix and polysilsesquioxane in a composition for preparing a carbon molecular sieve separation membrane according to the present invention. FIG. FIG. 1 (A) is a schematic view of a fluorine-containing polymer matrix of 6FDA-DAM: DABA (3: 2) LPMA64 (ladder-structured poly (phenyl-co-methacryl) silsesquioxane having the R ₁ and R ₂ ratio of 6: 4), LPG 64 (R ₁ and R ₂ in the formula And a ladder-structured poly (phenyl-co-pyridine) silsesquioxane having a ratio of R ₁ to R ₂ of the formula (1).

The composition for preparing a carbon molecular sieve separation membrane according to the present invention may include the polysilsesquioxane and the fluorine-containing polymer matrix in a weight ratio of 0.1: 99.9 to 99.9: 0.1. Specifically, the weight ratio may be 10:90 to 80:20. More specifically, it may be 5:95 to 30:70, but is not limited thereto. According to an embodiment of the present invention, the gas separation performance can be controlled according to the mixing ratio of the polysilsesquioxane and the fluorine-containing polymer matrix.

One embodiment of the present invention provides a carbon molecular sieve separator comprising the carbide of the above composition for producing a carbon molecular sieve separator.

The fluorine-containing polymer matrix of the composition for producing a carbon molecular sieve separator generates an etching gas such as fluorocarbon (CHF ₃ ) or hydrogen fluoride (HF). The polysilsesquioxane may form a secondary bond containing a hydrogen bond with the polymer matrix and may be uniformly bonded or non-uniformly dispersed without hydrogen bonding. In both cases, the polysilsesquioxane is formed by a pure polymer precursor It has relatively higher selectivity than the carbon molecular sieve separator. In the present specification, the "secondary bonding" means a bond between a molecule and a molecule. The secondary bond includes a hydrogen bond and a van der Waals bond, and is distinguished from a primary bond, which is a bond between elements such as an ionic bond.

In one embodiment, the present invention provides a fluorine-containing polymer having a fluorine-containing polymer when carbonizing the composition by using a composition comprising a mixture of the fluorine-containing polymer matrix and polysilsesquioxane as a precursor for preparing a carbon molecular sieve separator The etching gas generated in the matrix is etched to form ultramicropore in the carbon molecular sieve separator by etching the silica chemical moieties (eg, Si-O-Si, SiO ₂ and Si-C) of polysilsesquioxane .

In one embodiment, the carbon molecular sieve separator may include an ultramicropore having an average size of 1 Å or more and less than 6 Å. More specifically, the average size of the ultrafine pores may be 4 Å or more and less than 6 Å. Alternatively, the carbon molecular sieve separator may include an ultramicropore having an average size of less than 6 angstroms and a micropore having an average size of 6 to 20 angstroms. At this time, the sizes of the micropores and the micropores can be measured by analyzing the CO ₂ adsorption results measured at the low temperature of the carbon molecular sieve separator by the density functional theory.

More specifically, the carbon molecular sieve separation membrane may contain ultrafine pores and micropores in a volume or area ratio of 0.1: 99.9 to 10.0: 90.0. The carbon molecular sieve separator according to an embodiment of the present invention may further include micropores having molecular sieve functions in addition to micropores having high gas permeability, and may have a microporous structure and a microporous structure, The gas separation efficiency is excellent because the gas can be effectively separated.

The carbon molecular sieve separator according to the present invention may effectively separate gases having a molecular size difference of 0.1 A to 5 A as an embodiment. Specifically, the molecular size difference of the separable gases of the present invention is greater than 0.1 A, greater than 0.15 A, greater than 0.2 A, greater than 0.3 A, greater than 0.4 A, greater than 0.5 A, greater than 1 A, greater than 2 A, greater than 3 A, 4 Å or less, 4 Å or less, 3 Å or less, 2 Å or less, 1.5 Å or less, 1 Å or less, 0.8 Å or less, 0.6 Å or less, 0.5 Å or less, 0.4 Å or less, 0.3 angstroms or less, 0.2 angstroms or less, 0.1 angstroms. For example, the carbon molecular sieve separator may separate gases selected from the group consisting of oxygen / nitrogen, carbon dioxide / carbon tetrachloride, carbon dioxide / nitrogen, nitrogen / carbon tetrachloride, propylene / propane and ethylene / ethane. At this time, the molecular size of oxygen is about 3.46 Å, the molecular size of nitrogen is about 3.64 Å, the molecular size of carbon dioxide is about 3.3 Å, and the molecular size of carbon tetrachloride is about 3.8 Å. In the case of propylene and propane, the kinetic diameter of propylene is larger than that of propane (4.5 vs. 4.3 Å), but the minimum and minimum lengths of the molecules are smaller than propylene (4.0 vs. 4.2 Å & 5.1 vs. 5.4 Å) It can be separated by entropic selectivity.

One embodiment of the present invention is a method of manufacturing a carbon molecular sieve separator as described above, which comprises dissolving a composition comprising a polymer matrix containing fluorine and polysilsesquioxane in an organic solvent; A polymer separator manufacturing step of removing the organic solvent after filming the melt; And carbonizing the polymer separator.

In one embodiment, the organic solvent is N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), tetrahydrofuran (THF), and methylene chloride MC). However, the polymer matrix may include both the fluorine-containing polymer matrix and the polysilsesquioxane which can be removed after dissolving the fluorine-containing polymer matrix.

In one embodiment, the dissolving step may include mixing the fluorine-containing polymer matrix and the solids of the polysilsesquioxane and the organic solvent at a weight ratio of 0.1: 99.9 to 40: 60 by mixing. More specifically, the weight of the fluorine-containing polymer matrix and the solid content of the polysilsesquioxane is 0.1 wt% or less based on the total weight of the fluorine-containing polymer matrix and the solid content of the polysilsesquioxane and the organic solvent At least 1% by weight, at least 5% by weight, at least 10% by weight, at least 15% by weight, at least 20% by weight, at least 25% by weight, at least 30% by weight, at least 35% by weight or at least 40% by weight, Up to 40 wt%, up to 35 wt%, up to 30 wt%, up to 25 wt%, up to 20 wt%, up to 15 wt%, up to 10 wt% up to 5 wt% up to 1 wt% have. More specifically, the solid content of the fluorine-containing polymer matrix and the polysilsesquioxane is 0.1 to 40 wt%, 1 to 30 wt%, 5 to 20 wt%, or 7 to 13 wt% based on the total weight of the melt, &Lt; / RTI &gt; If the total weight of the fluorine-containing polymer matrix and the solids content of the polysilsesquioxane exceeds 40 wt% based on the total weight of the melt, it is difficult to form the carbon molecular sieve separator into a film, and if it is less than 0.1 wt% Is lowered.

In one embodiment of the present invention, the preparation method comprises the steps of adjusting at least one of a molecular weight and a weight ratio of a fluorine-containing polymer matrix and polysilsesquioxane contained in the composition to form an ultra micropore in a carbon molecular sieve separator And a step of adjusting the temperature. That is, the gas separation performance of the carbon molecular sieve separator can be controlled by adjusting the degree of etching of silicon by the mixing ratio of the polymer matrix and polysilsesquioxane under the same pyrolysis conditions.

For example, the separation performance of propylene and propene is improved as the content of polysilsesquioxane increases. Specifically, in the case of a composition not containing polysilsesquioxane, the selectivity of propylene / propene was 17.8 (-), but the polymer matrix containing polysilsesquioxane and fluorine was mixed at a weight ratio of 20:80 The selectivity of propylene / propene may be 102.2 (-).

In an embodiment of the manufacturing method according to the present invention, the gas separation performance can be controlled by controlling the degree of etching of silicon by controlling the carbonization temperature and the carbonization time. For example, the step of carbonizing the polymer separator may include the step of carbonizing the polymer separator within a temperature range of 500 to 1000 ° C. In one embodiment, the step of carbonizing the polymer separator may include carbonizing the polymer separator for 0.5 to 12 hours. In one embodiment, the step of carbonizing the polymer separator may include carbonizing the polymer separator under at least one of an argon atmosphere, a nitrogen atmosphere, an air atmosphere, and a vacuum.

An embodiment of the present invention can provide a method of separating a gas using the carbon molecular sieve separator. In one embodiment, the method may include passing the gas to be separated through the carbon molecular sieve separator. In one embodiment, the step may be a step of supplying the gas to the carbon molecular sieve separator, bringing the gas into contact with the separation membrane. In addition, the method may further include removing gas passing through the carbon molecular sieve separator.

According to one embodiment, the method may comprise separating one or more gases from two or more of the gaseous mixtures. In one embodiment, the method may also include separating gases having a molecular size difference of 0.1 A to 5 A. For example, separating a gas selected from the group consisting of oxygen / nitrogen, carbon dioxide / carbon tetrachloride, carbon dioxide / nitrogen, nitrogen / carbon tetrachloride, ethylene / ethane, and propylene / propane. In one embodiment, when the olefin / paraffin is separated, separation may be performed at a temperature of 80 ° C. or lower and a pressure of 16 atm or lower.

Hereinafter, the present invention will be described in more detail with reference to examples and accompanying drawings. It is to be understood by those skilled in the art that these embodiments are only for illustrating the present invention and that the scope of the present invention is not construed as being limited by these embodiments.

[Preparation Example 1] Preparation of polysilsesquioxane

A ladder-type silsesquioxane (LPPyr64) containing pyridine as the polysilsesquioxane according to one embodiment of the present invention was synthesized by the following method.

First, phenyltrimethoxysilane (0.24 mol) and 2-ethylpyridine trinethoxysilane (0.16 mol) were prepared as a trialkoxy mixed monomer. To prepare a mixed solvent, 40 g of HPLC grade tetrahydrofuran Distilled water (24 g) was prepared. Potassium carbonate (0.2 g) as a catalyst was previously dissolved in the prepared distilled water and stirred uniformly with tetrahydrofuran for 20 minutes.

Then, a mixed monomer solution of the prepared phenyltrimethoxysilane (0.24 mol) and 2-ethylpyridine trimethoxysilane (0.16 mol) was added dropwise to the aqueous solution, followed by stirring. After completion of the dropwise addition, the reaction proceeds at 25 ° C for 3 days. As the purification method, distillation is carried out using solvents which are not mixed with water such as chloroform, methylene chloride, toluene, and xylene and which can dissolve the polysilsesquioxane- Can be easily purified.

Structural analysis of ladder-type silsesquioxane (LPPyr64) containing the obtained pyridine was carried out by ¹ H NMR and ²⁹ Si NMR analysis, and is shown in FIG. 2 and FIG. 3.

- Mw = 24,000 (based on polystyrene)

- yield = 96%

LPMA64 is a ladder-type polysilsesquioxane according to another embodiment of the present invention, and LPMA64 is the same as the ladder polysilsesquioxane according to another embodiment of the present invention except that 3-methacryloylpropyltrimethoxysilane is used instead of 2-ethylpyridine trimethoxysilane in the above- &Lt; / RTI &gt; LPG64 can be produced by the same method except that 3-glycidoxypropyltrimethoxysilane is used instead of 2-ethylpyridine trimethoxysilane in the above production process.

[Preparation Example 2] Preparation of carbon molecular sieve separation membrane composition and polymer membrane

A composition for preparing a carbon molecular sieve separator according to an embodiment of the present invention was prepared by the following method.

First, Preparation Example 1 (LPPyr 64) was dissolved in a solvent matrix of 6FDA-DAM: DABA (3: 2) (PI) (Akron Polymer Systems, USA) and ladder-type polysilsesquioxane (LPSQ) as a polymer matrix containing fluorine And dissolved in tetrahydrofuran (THF, (> 99.0% purity, Dae Jung, Korea) as shown in the following table.

Sample Unit 6FDA-DAM: DABA (3: 2) LPSQ THF Total 6FDA-DAM: DABA (3: 2) (Comparative Example 1) Wt% 5.0 0.0 95.0 100.0 6FDA-DAM: DABA (3: 2)
/ LPPyr 64 (90/10 wt / wt) (Example 1) Wt% 4.5 0.5 95.0 100.0 6FDA-DAM: DABA (3: 2)
/ LPPyr 64 (80/20 wt / wt) (Example 2) Wt% 4.0 1.0 95.0 100.0

After mixing for 12 hours over the roller for complete dissolution, residual impurities of the uniformly dissolved polymer solution were removed by syringe pad. The film was produced by melt casting technique on a Teflon plate with a Teflon casting ring. In order to allow the solvent to evaporate slowly, the melt casting was carried out in a glove bag saturated with THF. After 12 hours, the vitrified films were vacuum dried at 120 &lt; 0 &gt; C for 12 hours to remove residual solvent. The dried film was cut into a circular shape by hammering a sharp die cutter with a hammer to reduce cutting stress. The thickness of the prepared film was uniformly 80 ± 10 μm.

[Manufacturing Example 3] Production of carbon molecular sieve separator

As one embodiment of the present invention, the polymer separator membrane prepared in Preparation Example 2 was carbonized through a thermal decomposition apparatus to produce a carbon molecular sieve separator.

Specifically, the polymer membrane prepared in Preparation Example 2 was placed on a stainless steel mesh plate (Ecosolution, Korea), and then placed in the center of a quartz tube (MTI, USA) and fixed with three stainless steel poles. Figure 4 shows a pyrolyzer setup. Three zone furnace (Thermocraft, USA) and three separate thermometers were used in connection with a seven zone thermo controller (Omega, USA) to accurately and uniformly control the temperature inside the quartz tube. Both ends of the quartz tube were enclosed by assembling a metal flange with a silicone o-ring. During the pyrolysis, ultrapure argon was flowed through a mass flow controller (MKP, Korea) at a flow rate of 1500 cm ³ / min through a quartz tube to produce an ultra-high purity argon atmosphere, which was observed through an oxygen analyzer (Cambridge seosotec Ltd, UK). The temperature conditions were heated from 50 DEG C to 250 DEG C at a rate of 13.3 DEG C / min and at 250 DEG C to 3.60 DEG C / min at 660 DEG C as in the thermal decomposition temperature protocol shown in Table 2 below. For accurate temperature control, the temperature was slowly increased to 675 ° C at 0.25 ° C / min from 660 ° C, maintained at 675 ° C for 2 hours, and slowly cooled to room temperature.

Initial Temperature (℃) Final Temperature (℃) Ramp Rate (° C / min) 50 250 13.3 250 660 3.85 660 675 0.25 675 675 Soak for 2 hours

After pyrolysis, the quartz tube and the mesh plate were reheated in an air atmosphere at 800 ° C. The residues were rubbed with sandpaper and washed with acetone.

5 is a photograph of a carbon molecular sieve separator prepared by using 6FDA-DAM: DABA (3: 2) / LPSQ (90/10 wt / wt) (Example 1) of Production Example 2 as a precursor.

[Test Example 1] Bonding structure of fluorine-containing polymer matrix and polysilsesquioxane

In order to analyze the bonding structure between the fluorine-containing polymer matrix and polysilsesquioxane in the composition for preparing a carbon molecular sieve separator according to an embodiment of the present invention, the following experiment was conducted.

First, LPFyr 64, LPMA64, and LPG64 were synthesized by using 6FDA-DAM: DABA (3: 2) (PI) (Akron Polymer Systems, USA) as the polymer matrix containing fluorine and ladder-type polysilsesquioxane 1, mixed at a weight ratio of 90:10, and dissolved in an organic solvent in the same manner as in Preparation Example 2 to prepare a polymer membrane. (Examples 1, 3, and 4, respectively)

The mixture was cut from liquid nitrogen, coated with platinum and observed at 10 kV through a field emission scanning electron microscopy (FE) (Inspection F (FEI)) to observe the cross-section of the mixture in the separator.

FIG. 6 shows the SEM image, with the left images being a low resolution image and the right images being a high resolution image. For example, as shown in (C-1) and (C-2), the 6FDA-DAM: DABA (3: 2) / LPPyr64 (90/10 wt / 3: 2), and a pyridine of LPPyr 64, and thus the structure is close to a single phase.

[Test Example 2] Interaction and chemical structure of a fluorine-containing polymer matrix and polysilsesquioxane

In order to analyze the interaction and the chemical structure between the polymer matrix containing fluorine and the polysilsesquioxane in the composition for preparing a carbon molecular sieve separator according to an embodiment of the present invention, 6FDA-DAM: DABA (3 (Example 1), PI / LPPyr64 (80/20 wt / wt) (Example 2), PI / LPMA64 (90/10 wt / / DAP (3: 2) and LPPyr64, LPMA64, and LPG64 (Example 3) were prepared by preparing PI / LPG64 (90/10 wt / The action was observed using FT-IR (Fourier transfer infrared spectroscopy, FT-IR frontier, Perkin-Elmer).

Figure 7 shows FT-IR spectra of a mixture of 6FDA-DAM: DABA (3: 2) (PI), 6FDA-DAM: DABA (3: 2) (PI) and LPSQ. According to the results of FT-IR measurement, the mixture of 6FDA-DAM: DABA (3: 2) (PI) and LPSQ formed strong hydrogen bonds and the C = O stretching peak of the carboxylic acid had a high wavenumber As shown in FIG.

FIG. 8 shows the chemical structure of the ladder-type polysilsesquioxane according to the organic functional group through the FT-IR.

[Test Example 3] Pyrolysis behavior of a composition for preparing a carbon molecular sieve separation membrane 1

(TGA, TGA1 (METTLER TOLEDO)) was used to confirm the pyrolysis behavior of the composition for preparing a carbon molecular sieve separator comprising a polymer matrix containing fluorine and polysilsesquioxane according to an embodiment of the present invention Respectively.

LP / LPPyr 64 (90/10 wt / wt) (Example 1), PI / LPPyr 64 (80 / 20 wt / wt) (Example 2) and LPPyr 64 (Comparative Example 2) were prepared, and then treated under the same conditions as the pyrolysis conditions for producing the carbon molecular sieve. That is, 10 to 15 mg of each of the above samples was placed in a ceramic pen, and the interior of the chamber was purged with ultrahigh-purity argon (99.9999%) at a flow rate of 50 ml / min for 30 minutes at 50 ° C. The temperature conditions were set under the same conditions as those in Table 2 above. Specifically, it was heated from 50 캜 to 250 캜 at a rate of 13.3 캜 / min and at 250 캜 was heated to 660 캜 at a rate of 3.85 캜 / min. For accurate temperature control, the temperature was slowly increased to 675 ° C at 0.25 ° C / min from 660 ° C, maintained at 675 ° C for 2 hours, and slowly cooled to room temperature.

As shown in Fig. 9, it can be confirmed that the mass loss is gradually reduced in the vicinity of 350 DEG C in Comparative Example 1, Examples 1 and 2 including 6FDA-DAM: DABA (3: 2). This is probably due to the generation of carbon dioxide by decarboxylation of the DABA moiety. Also, in Comparative Example 1, Examples 1 and 2, mass reduction occurred rapidly at about 450 ° C, and the change in mass decrease was gentle at 650 ° C or higher.

In particular, Examples 1 and 2, which are one embodiment of the present invention, showed a reduction in mass compared to Comparative Examples 1 and 2, which contained only one of the fluorine-containing polymer matrix and the ladder-type polysilsesquioxane. It is considered that additional mass reduction occurred by etching the silica chemical moieties of the etching gas (eg, HF or CHF ₃ ) generated during the pyrolysis process. In other words, in Examples 1 and 2 according to the present invention, a carbon molecular sieve separator is prepared using a fluorine-containing polymer matrix and a polysilsesquioxane-containing composition as precursors, thereby obtaining a composition containing only one of the two substances As a result, a super-high-strength ball is further formed, so that it has improved gas separation performance.

[Test Example 4] Pyrolysis behavior of composition for preparing carbon molecular sieve separator 2

In order to more clearly analyze the results of Test Example 3, elemental analyzes (EA) were performed as follows.

An elemental analyzer (EA, FLASH 2000 CHN / CHNS Automatic Elemental Analyzer (Thermo scientific)) was used to check the content of carbon, hydrogen, and nitrogen, and the weight ratio of oxygen was observed through 1108 CHNS-O (FISONS Instruments). Ion chromatography was used to check fluorine content. Finally, the weight ratio of silicon was confirmed by total dissolution technique using ICP-OES (Inductively coupled plasma optical emission spectrometry, i CAP 6000 series (Thermo)).

LP / LPPyr 64 (90/10 wt / wt) (Example 1), PI / LPPyr 64 (80/20 wt / wt) wt) (Example 2), and Table 4 shows the elemental analysis results of the carbon molecular sieve membranes obtained by pyrolyzing the polymer membranes.

Element (wt%) C H N O F Si PI (Comparative Example 1) 52.71 2.33 4.35 16.31 24.30 0.00 PI / LPPyr64
(90/10 wt / wt) (Example 1) 52.42 2.60 4.45 15.55 24.23 0.75 PI / LPPyr64
(80/20 wt / wt) (Example 2) 51.49 2.90 4.50 14.95 24.17 2.00

Element (wt%) C H N O F Si CMS_PI (carbon molecular sieve separator of Comparative Example 1) 79.52 2.95 5.45 12.08 0.00 0.00 CMS_PI / LPPyr64
(90/10 wt / wt) (carbon molecular sieve separator of Example 1) 78.85 1.97 5.75 13.40 0.00 0.03 CMS_PI / LPPyr64
(80/20 wt / wt) (carbon molecular sieve separator of Example 2) 77.04 0.35 7.04 14.92 0.00 0.65

As shown in Tables 3 and 4, in Example 1, the silicon element content decreased from 0.75 to 0.03, and in Example 2, the silicon element content decreased from 2.00 to 0.65. From these results, it can be seen that the carbon molecular sieve separators of Examples 1 and 2 according to one embodiment of the present invention have a significantly reduced silicon element content relative to the respective polymer separators (precursors).

[Test Example 5] Composition for preparing a carbon molecular sieve separator and its carbon molecular sieve separator Crystallinity and chain packing

In order to confirm the crystallinity and chain packing of the composition for preparing a fluorine-containing polymer matrix and a carbon molecular sieve separator containing polysilsesquioxane and a carbon molecular sieve separator according to an embodiment of the present invention, Were carried out.

The crystallinity and chain packing were confirmed by using Wide angle X-ray diffraction (WAXD, Dmax 2500 / PC (Rigaku)) using CuK _? Radiation (? = 1.5406?). The d-spacing values were calculated by Bragg's law (d = λ / 2 sin θ) and the 2θ values were measured from 5 to 50 °.

As a result, as shown in Fig. 10, the ratio of 6FDA-DAM: DABA (3: 2) (PI: Comparative Example 1), PI / LPPyr64 (90/10 wt / (80/20 wt / wt) (Example 2) and LPPyr 64 (Comparative Example 2) polymer membranes (precursors) did not significantly change the average d-spacing value depending on the polymer content. In the case of LPPyr 64 (Comparative Example 2), intrinsic peaks of interstain distance and intra chain distance of ladder polysilsesquioxane were 7.3 ° and 19.5 °, respectively. On the other hand, in the case of the carbon molecular sieve separator, as shown in FIG. 11, it can be seen that the average d-spacing value of the carbon molecular sieve increases as the content of LPPyr 64 increases. This is because the chain packing was disturbed by LPPyr64 in the carbonization.

[Test Example 6] Carbon molecular sieve separation membrane analysis

The composition PI / LPPyr 64 (90/10 wt / wt) (Example 1) and the PI / LPPyr 64 composition for preparing a carbon molecular sieve separator containing a polymer matrix containing fluorine and ladder polysilsesquioxane according to an embodiment of the present invention, The carbon molecular sieve separator prepared by carbonization of LPPyr 64 (80/20 wt / wt) (Example 2) and the polymer separator of LPPyr 64 (Comparative Example 2) was analyzed by ²⁹ Si NMR (Nuclear Magnetic Resonance) Respectively.

(1/10), 6/10 (DA): DABA (3: 2) (PI: Comparative Example 1), PI / LPPyr64 (90/10 wt / Example 2 An image photographed by scanning transmission electron microscopy (STEM) is shown in Fig. 13 to show the shape of the inorganic phase in the carbon molecular sieve separating film carbonized. The acceleration voltage of the electron beam was 300 KeV, and the size of the scanning electron beam was about 0.1 nm. 13 (A) is a STEM image of CMS_PI, (B) CMS_PI / LPPyr64 (90/10 wt / wt) and (C) CMS_PI / LPPyr64 (80/20 wt / wt).

[Test Example 7] Gas permeability and selectivity of carbon molecular sieve separator

DAF (3: 2) (PI: Comparative Example 1) and PI / LPPyr64 (90/10 wt / wt) (Example 1) were used in order to analyze the gas permeability and selectivity of the carbon molecular sieve separator. , Carbon monolayers (CMS) were prepared by carbonizing PI / LPPyr 64 (80/20 wt / wt) (Example 2) at 675 ° C. and then a single gas CO ₂ , N ₂ , CH ₄ , C ₃ H ₆ And C ₃ H ₈ was measured at 35 ° C and 1 atm. The results are shown in Table 5 below.

Fig. 14 is a graph showing the results of the experiment of the 6FDA-DAM: DABA (3: 2) (PI: Comparative Example 1), PI / LPPyr64 (90/10 wt / (A) CO ₂ / N ₂ , (B) CO ₂ / CH ₄ , (C) C ₃ H ₆ / C ₃ H ₈ of carbonized molecular sieve separator (CMS) Permeability and selectivity, respectively. FIG. 15 is a graph showing the results of the experiment of the 6FDA-DAM: DABA (3: 2) (PI: Comparative Example 1), PI / LPPyr64 (90/10 wt / (C ₃ H ₆ / C ₃ H ₈ ) to the propylene (C ₃ H ₆ ) permeability of the polymer upper bound and CMS upper bound of the propylene / propane (Example 2) Respectively.

CO ₂
(Barrer) N ₂
(Barrer) CH ₄
(Barrer) C ₃ H ₆
(Barrer) C ₃ H ₈
(Barrer) CO ₂ / N ₂
(-) CO ₂ / CH ₄
(-) C ₃ H ₆ / C ₃ H ₈
(-) CMS_PI 4351.18
± 800.63 125.21
± 32.61 93.35
± 31.33 630.23
± 184.24 35.47
± 12.61 34.8 ± 2.7 46.6 ± 7.1 17.8 ± 1.1 CMS_PI / LPPyr64
(90/10 wt / wt) 2633.83
± 375.53 76.79
± 14.19 50.77
± 9.97 291.11
± 87.07 6.69
± 0.81 34.3 ± 1.4 51.9 ± 2.8 43.5 ± 7.7 CMS_PI / LPPyr64
(80/20 wt / wt) 1606.73
± 331.43 43.33
± 9.53 26.15
± 5.86 69.52
± 18.62 0.68
± 0.41 37.1 ± 0.5 61.4 ± 1.1 102.2 + 34.3

As a result, as shown in Table 5 and FIGS. 14 and 15, Comparative Example 1 and Examples 1 and 2 including 6FDA-DAM: DABA (3: 2) showed excellent gas separation performance. This is due to ultramicropore and micropore formed during carbonization. In particular, a structure having a larger free volume is formed by the decarboxylation reaction.

In addition, it was confirmed that the permeability of all the gases decreases as the content of the Example 2, that is, the ladder type polysilsesquioxane (LPPyr 64), is increased. This is because as the amount of LPPyr 64, which is relatively small compared to 6FDA-DAM: DABA (3: 2), increases, the free energy of the composition for preparing a carbon molecular sieve separator, which is a precursor of the carbon molecular sieve separation membrane, The volume ratio (FFV) decreases, and the FFV of the carbon molecular sieve separator also decreases, resulting in a decrease in the permeation performance. On the other hand, Examples 1 and 2 showed better gas selectivity than Comparative Example 1.

On the other hand, in the case of separation of propylene and propene (C ₃ H ₆ / C ₃ H ₈ ), Example 2 exhibited remarkably superior performance (C ₃ H ₆ (Barrer): 61.59, C ₃ H ₆ / C ₃ H ₈ (-): 140.0), indicating that the separation performance (selectivity) between gases having a small particle size difference is excellent. This is because the silica chemical moieties are etched by the etching gas (HF or CHF ₃ ) generated from the 6FDA during the formation of the carbon molecular sieve separator (CMS), resulting in the formation of more ultra-fine balls capable of separating C ₃ H ₆ and C ₃ H ₈ .

In order to confirm the formation of the micropores, the pore distribution of the carbon molecular sieve was confirmed as follows.

CO ₂ adsorption amount was measured by BET (Brunauer-Emmett-Teller) at low temperature CO ₂ adsorption experiment (ASAP 2020 (Micromeritics)) and carbon molecular sieve separator (CMS ) Pore size. The low temperature CO ₂ adsorption experiments were carried out at 273.15 K at an absolute pressure of 1-640 mmHg.

As a result, as shown in FIG. 16, as the content of LPPyr 64, which is a ladder-type polysilsesquioxane, was increased, it was found that the carbon molecular sieve separator (CMS) contained various pore sizes. Especially, as the content of LPPyr 64 was increased, ultrafine pore (<6 Å) peaks increased not only significantly but also became more granular and clear. Considering that the minimum and the minimum lengths of the molecules are smaller than propylene (4.0 vs. 4.2 Å & 5.1 vs. 5.4 Å), excellent C ₃ H ₆ / C ₃ H ₈ separation by entropic selectivity It was possible.

Table 6 below shows a carbon molecular sieve separator (CMS_PI) containing no ladder polysilsesquioxane, a carbon molecular sieve separator (CMS_PI / LPPyr64 (90/10 weight / weight) containing 10% by weight of ladder polysilsesquioxane, (CMS_PI / LPPyr64 (80/20 wt / wt)) containing 20 wt% of ladder-type polysilsesquioxane and a total microcavity of less than 20 Å and ultrafine pore volume of less than 6 Å Respectively. As shown in Table 6, as the content of LPPyr 64, which is ladder polysilsesquioxane, increases, the ratio of ultrafine pores to the total micropore volume of 6 Å or less including the corresponding carbon molecular sieve separator (CMS) increases can confirm.

Total micropore volume
(&Lt; 20 A) (cm &lt; ³ &gt; / g) Ultrafine pore volume
(<~ 7 Å) (cm ³ / g) Volume fraction (%) of ultrafine pores (<~ 7 Å) to total micropores (<20 Å)
CMS_PI 0.85 1.16E-02 1.37 CMS_PI / LPPyr64
(90/10 wt / wt) 0.68 1.02E-02 1.50 CMS_PI / LPPyr64
(80/20 wt / wt) 0.56 9.01E-03 1.61

[Test 8] Separation performance of carbon separator according to organic functional groups of polysilsesquioxane

To confirm the gas permeability and selectivity of the carbon separator according to the organic functional groups of the polysilsesquioxane used as the precursor, 6FDA-DAM: DABA (3: 2) (PI), PI / LPPyr64 (CMS) was prepared by carbonization of PI / LPG64 (80/20 wt / wt) at 675 ℃. The permeability of single gas C ₃ H ₆ and C ₃ H ₈ was measured at 35 ℃, 1 atmospheric pressure.

As shown in FIG. 17, CMS_PI / LPG64 (80/20 wt / wt) has improved C ₃ H ₆ / C ₃ H ₈ selectivity and reduced C ₃ H ₆ permeability than CMS_PI as in the case of CMS PI / Respectively. That is, even in the case of the carbon molecular sieve of the LPG64 mixed precursor, the etching effect using the fluorine gas changed the ultrafine pore structure as in the case of the carbon molecular sieve of the precursor mixed with LPPyr64.

Claims (25)

A polymer matrix containing fluorine; And
Polysilsesquioxane;
Wherein the carbon molecular sieve separator comprises a carbon nanofibers. The method according to claim 1,
Wherein the polysilsesquioxane is a ladder-type polysilsesquioxane represented by the following formula (1):
[Chemical Formula 1]

In Formula 1,
R ₁ , R ₂ and R ₃ are each independently selected from the group consisting of aromatic phenyl, heteroaromatic phenyl, aliphatic alkyl, cyclic aliphatic alkyl, vinyl, aryl, methacrylate, acrylate, Functional group, and n is an integer selected from 1 to 10,000. The method according to claim 1,
Wherein the fluorine-containing polymer matrix comprises a 6-FDA-based polyimide (2,2-bis (3,4-carboxyphenyl) hexafluoropropane dianhydride based polyimide). The method of claim 3,
The 6-FDA polyimide may be selected from the group consisting of 6FDA-DAM (diamino-mesitylene), 6FDA-mPDA (m-phenylenediamine), 6FDA- DABA (diaminobenzoic acid), 6FDA- 1: -DETDA, 6FDA-1,5 ND: ODA (1: 1), 6FDA-DETDA: DABA (3: 2), 6FDA- DAM: mPDA (3: 2), 6FDA- DAM: DABA ) And 6FDA-mPDA: DABA (3: 2). The method according to claim 1,
Wherein the polysilsesquioxane has a number average molecular weight of from 10 ² to 10 ⁸ . The method according to claim 1,
Wherein the fluorine-containing polymer matrix and the ladder-type polysilsesquioxane are bonded by a secondary bond including a hydrogen bond. The method according to claim 1,
Wherein the polysilsesquioxane and the fluorine-containing polymer matrix have a weight ratio of 10:90 to 80:20. A carbon molecular sieve separator comprising a carbide of the composition for preparing a carbon molecular sieve separator according to any one of claims 1 to 7. The carbon molecular sieve separator according to claim 8, wherein the carbon molecular sieve separator comprises an ultramicropore having an average size of less than 1 Å and less than 6 Å. The carbon molecular sieve separator according to claim 8, wherein the carbon molecular sieve separator comprises an ultramicropore having an average size of less than 6 angstroms and a micropore having an average size of 6 to 20 angstroms. 11. The carbon molecular sieve separator according to claim 10, wherein the carbon molecular sieve separator comprises ultrafine pores and micropores in a volume or area ratio of 0.1: 99.9 to 10.0: 90.0. The carbon molecular sieve separator according to claim 8, wherein the carbon molecular sieve separator is a carbon molecular sieve separator which separates a gas selected from the group consisting of oxygen / nitrogen, carbon dioxide / carbon tetrachloride, carbon dioxide / nitrogen, nitrogen / carbon tetrachloride, ethylene / ethane and propylene / . A dissolution step of dissolving a composition comprising a fluorine-containing polymer matrix and polysilsesquioxane in an organic solvent;
A polymer separator manufacturing step of removing the organic solvent after filming the melt; And
Carbonizing the polymer separator;
Wherein the carbon molecular sieve separator comprises a carbon nanofibers. 14. The method of claim 13, wherein the carbon molecular sieve separator comprises a carbide of the composition for preparing a carbon molecular sieve separator according to any one of claims 1 to 7. The method of claim 13, wherein the organic solvent is selected from the group consisting of N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), tetrahydrofuran (THF), and methylene chloride chloride, MC). &lt; / RTI &gt; 15. The method of claim 14, wherein the dissolving step comprises mixing the fluorine-containing polymer matrix and the solids of the polysilsesquioxane and the organic solvent in a weight ratio of 0.1: 99.9 to 40: Self-separating membrane manufacturing method. [14] The method of claim 13, wherein the preparation method comprises the steps of adjusting at least one of a molecular weight and a weight ratio of the fluorine-containing polymer matrix and the polysilsesquioxane contained in the composition to form an ultra micropore Forming a carbon molecular sieve separator. 14. The method of claim 13, wherein the step of carbonizing the polymer separator comprises carbonizing the polymer separator within a temperature range of 500-1000 &lt; 0 &gt; C. 14. The method of claim 13, wherein the step of carbonizing the polymer separator comprises carbonizing the polymer separator for 0.5 to 12 hours. 14. The method of claim 13, wherein the step of carbonizing the polymer separating membrane comprises carbonizing the polymer separating membrane under at least one of an argon atmosphere, a nitrogen atmosphere, an air atmosphere, and a vacuum. A method for separating one or more gases from two or more mixed gases using the carbon molecular sieve separator of claim 9. 22. The method of claim 21, wherein the method comprises separating gases having a molecular size difference of from 0.1 to 5 Angstroms. 23. The method of claim 22, further comprising separating the gas comprising separating a gas selected from the group consisting of oxygen / nitrogen, carbon dioxide / carbon tetrachloride, carbon dioxide / nitrogen, nitrogen / carbon tetrachloride, ethylene / ethane, olefin / paraffin, and propylene / How to. 22. The method of separating gas according to claim 21, wherein the method comprises passing the two or more mixed gases through the carbon molecular sieve separator. 25. The method of claim 24, wherein the method further comprises removing gas that has passed through the carbon molecular sieve separator.

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