KR101998693B1 - Triblock copolymers using catalytic polymerization and method for manufacturing the same - Google Patents

Abstract

The triblock copolymer according to the present invention has a BAB-type arrangement in which the soft segment A and the hard segment B are repeatedly formed. By forming the ion channel by the self-assembled structure, which is formed by controlling the fine phase separation between the different blocks and the ratio of the blocks, The conductivity can be improved.
The triblock copolymer according to the invention according to the invention comprises soft segment A; And a hard segment B, and has a BAB type arrangement by a single combination of the soft segment A and the hard segment B.

Description

TECHNICAL FIELD The present invention relates to a triblock copolymer and a method for producing the triblock copolymer,

The present invention relates to a triblock copolymer, and more particularly, to a triblock copolymer comprising recurring units of soft segment A and hard segment B by catalytic polymerization and a method for producing the same.

The electrolyte used in the secondary battery has a function of transferring lithium ions and is divided into a liquid electrolyte and a solid electrolyte. The liquid electrolyte has a high ionic conductivity, but has disadvantages such as detonation due to disconnection and water leakage. Solid electrolytes have good thermal stability and mechanical stability, but low ionic conductivity.

Solid electrolytes, such as LiPON or lithiated borates, generally have relatively low glass transition temperatures of 250-300 < 0 > C and during the step of assembling the battery by pressurized annealing of different layers, The electrolyte material can be partially crystallized and the ion conduction characteristics can be changed.

As a representative polymer electrolyte, there is a PEO-based polymer electrolyte. The PEO-based polymer has a low glass transition temperature and high flexibility, and can move ions through coordination bonding of lithium ions and oxygen atoms in the main chain. However, when it has a high molecular weight, the crystal structure appears at 60 ° C or less, which is disadvantageous in decreasing the ionic conductivity. In addition, when it is a low molecular weight, it is in a liquid state, which makes it difficult to use it as an all solid battery.

A related art related to the present invention is Korean Patent Laid-Open Publication No. 10-2017-0028391 (published on Mar. 13, 2013), which discloses a pre-solid battery comprising a layer of a solid electrolyte and a polymer material .

It is an object of the present invention to provide a triblock copolymer having an excellent ionic conductivity.

Another object of the present invention is to provide a method for producing a triblock copolymer having an excellent ionic conductivity.

In order to accomplish the above object, the triblock copolymer according to the present invention comprises soft segment A; And a hard segment B containing a urethane group (-NHCOO-) in the main chain, and having a B-A-B arrangement by a single bond of the soft segment A and the hard segment B.

The soft segment A may be represented by the following general formula (1).

[Chemical Formula 1]

M is an integer of 1 to 1000, and R ₁ and R ₂ are ethylene glycol compounds.

The hard segment B having an allyl group in the main chain may be represented by the following general formula (2).

(2)

N 'is an integer of 1 to 1000, and R ₃ is a substituted or unsubstituted aryl group.

The R < ₃ > may be naphthalene.

The hard segment B containing a urethane group (-NHCOO-) in the main chain may be represented by the following general formula (3).

(3)

Wherein n is an integer of 1 to 1000

The ratio of the segment A to the total repeating units in the triblock copolymer may be larger than that of the segment B. [

The mixing ratio of segment A: segment B to the total repeating units in the triblock copolymer may be 1: 0.1 to 1: 0.5 in molar ratio.

The triblock copolymer may be a triblock copolymer for a lithium battery electrolyte.

According to another aspect of the present invention, there is provided a method of manufacturing a triblock copolymer, including: (a) synthesizing a soft segment A; And (b) ring-opening polymerization by mixing the soft segment A, the catalyst, and the organic solvent with a glycidyl derivative, wherein the glycidyl derivative is synthesized as a hard segment B by ring-opening polymerization, And a BAB type arrangement by a single combination of the hard segment B and the hard segment B, respectively.

According to another aspect of the present invention, there is provided a method of manufacturing a triblock copolymer, including: (a) synthesizing a soft segment A; And (b) condensing and polymerizing the soft segment A, the catalyst, and the organic solvent with an isocyanate derivative, wherein the isocyanate derivative is synthesized by condensation polymerization to a hard segment B containing a urethane group in the main chain, And has a BAB type arrangement by a single combination of the soft segment A and the hard segment B.

In the first embodiment or the second embodiment, the soft segment A may be represented by the following formula (1).

[Chemical Formula 1]

M is an integer of 1 to 1000, and R ₁ and R ₂ are ethylene glycol compounds.

In the first embodiment or the second embodiment, in the step (a), ring-opening polymerization can be carried out by mixing an ethylene glycol monomer containing a glycidyl group, an initiator represented by the following formula (4), a catalyst and an organic solvent .

[Chemical Formula 4]

In the first embodiment, the hard segment B may be represented by the following general formula (2).

(2)

N 'is an integer of 1 to 1000, and R ₃ is a substituted or unsubstituted aryl group.

The R < ₃ > may be naphthalene.

In the second embodiment, the hard segment B containing a urethane group (-NHCOO-) in the main chain may be represented by the following general formula (3).

(3)

Wherein n is an integer of 1 to 1000

In the first embodiment or the second embodiment, the catalyst may include at least one of t-Bu-P ₁ , TiBP, t-Bu-P ₂ and t-Bu-P ₄ .

The triblock copolymer according to the present invention has a BAB-type arrangement in which the soft segment A and the hard segment B are repeatedly formed. By forming the ion channel by the self-assembled structure, which is formed by controlling the fine phase separation between the different blocks and the ratio of the blocks, The conductivity can be improved.

In addition, since the soft segment A plays a role of preventing crystallization in the copolymer and at the same time it transfers ions, it can exhibit a high ionic conductivity.

Further, by introducing the hard segment B into the copolymer, the polymer can be changed into a solid phase to improve the mechanical properties and can be applied to a solid electrolyte.

1 shows NMR results of TG and NG monomers according to the present invention.
2 shows NMR results of PTG and PNG-PTG-PNG triblock copolymer according to the present invention.
3 is a graph showing a molecular weight distribution diagram of PTG according to the present invention.
4 is a graph showing a molecular weight distribution diagram of the PNG-PTG-PNG triblock copolymer according to the present invention.
5 is a TGA, DSC analysis result of PEO, PTG, PNG, and PNG-PTG-PNG triple block copolymers according to the present invention.
6 shows XRD analysis results of the PNG, PNG-PTG-PNG triplet block copolymer according to the present invention.
FIG. 7 shows the results of ionic conductivity measurement and VTF plot of PEO, PTG, and PNG-PTG-PNG triblock copolymers according to the present invention.
FIGS. 8 and 9 are TEM images showing the fine phase separation structure of the PNG-PTG-PNG triplet block copolymer according to the present invention. FIG.
10 is a graph showing electrical characteristics of the PNG-PTG-PNG triblock copolymer according to the present invention.
11 shows NMR and GPC analysis results of PAGE according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

The triblock copolymers according to the invention comprise soft segment A and hard segment B.

The hard segment refers to a portion having a relatively rigid physical property in a block copolymer, and the soft segment means a portion having relatively soft properties in a block copolymer.

The glass transition temperature of the hard segment may be 40 占 폚 or higher, for example, 40 占 폚 to 200 占 폚. Within the range of the above-mentioned glass transition temperature, the hard segment may exist in glass at room temperature and may have rigid physical properties. The glass transition temperature of the soft segment may be 10 占 폚 or lower, for example, -80 占 폚 to 10 占 폚. Within the range of the glass transition temperature as described above, the soft segment can have molecular flow property at room temperature, and can have soft properties.

The triblock copolymer of the present invention comprises a soft segment A, and a hard segment B.

The soft segment A is represented by the following formula (1), and the hard segment (B) is represented by the following formula (2) or (3). The triblock copolymer of the present invention preferably has a B-A-B arrangement by a single bond of the soft segment A and the hard segment B.

[Chemical Formula 1]

(2)

(3)

Each of m, n 'and n is independently an integer of 1 to 1000.

R ₁ and R ₂ are ethylene glycol compounds. A functional group may be further bonded to the ends of R ₁ and R ₂ in which the ethylene glycol compound is formed. -CN or the like can be introduced at the terminal to increase the density of the conductive ions and improve the ionic conductivity. In addition, ion conductivity can be improved by introducing a lithium salt, and ionic groups such as quaternary ammonium salts can be introduced to increase the dielectric constant and the density of the conductive ions, thereby improving the ionic conductivity.

The R ₃ is a substituted or unsubstituted aryl group, specifically, naphthalene. In order to improve the mechanical properties of the solid electrolyte, the present invention can solidify liquid phase PTEGGE (poly (triethylene glycol glycidyl ether)) by stacking p (pi) - pi (n) between naphthyl structures. Soft segment A serves both to prevent crystallization and to transfer ions. Thus, a solid electrolyte for a battery having mechanical stability and high ion conductivity can be produced.

It is preferable that the ratio of the segment A to the total repeating units in the triblock copolymer is larger than that of the segment B. [ Specifically, the mixing ratio of the segment A: segment B to the total repeating units in the triblock copolymer may be 1: 0.1 to 1: 0.5 in terms of the molar ratio. As the ratio of the segment B increases in this range, it can be confirmed that the wax is changed from a wax-like state to a solid state. When the molar ratio of B is less than 0.1, the B block does not serve as a hard segment, so that the polymer may not be solidified. Conversely, when the molar ratio of B is larger than 0.5, the proportion of the soft segment A serving to transfer ions may be reduced and the ion conductivity may be lowered.

The triblock copolymer may be applied to an electrolyte of a lithium battery.

The method for producing a triblock copolymer according to the first embodiment of the present invention includes a step (S110) of synthesizing soft segment A, a step of performing ring-opening polymerization by mixing a soft segment A, a catalyst and an organic solvent and a glycidyl derivative (S120).

The step of synthesizing the soft segment A (S110)

First, a soft segment A represented by the following formula (1) is synthesized.

[Chemical Formula 1]

R ₁ and R ₂ are the same as described above.

In order to synthesize the soft segment A, ring-opening polymerization is carried out by mixing an ethylene glycol monomer containing a glycidyl group, an initiator, a catalyst and an organic solvent. The ethylene glycol-based monomer containing the glycidyl group may include one epoxide ring, which may cause ring opening polymerization. The ring opening may be initiated by the reaction of the hydroxy group end group contained in the initiator and the basic catalyst used. The ring-opened epoxide continuously opens the glycidyl epoxide in the presence of a base. The ring-opening polymerization can be carried out, for example, at 25 to 60 캜 for 12 to 24 hours, and can be adjusted according to the desired polymerization degree and the temperature of the reaction mixture.

The glycidyl group-containing ethylene glycol monomer may be synthesized from an epoxy derivative, for example, by the method of Formula 1 below.

[Formula 1]

Triethyleneglycol glycidyl ether (TG) is synthesized by ring-opening polymerization of epichlorohydrin and triethylene glycol in the presence of a base.

The TG is synthesized as a soft segment A by ring-opening polymerization in the presence of an initiator and a catalyst,

[Formula 2]

The initiator preferably includes an alcohol, and may include an initiator represented by the following formula (4).

[Chemical Formula 4]

The catalyst exhibits strong basicity as an anion ring-opening polymerization catalyst. For example, the catalyst may comprise at least one of t-Bu-P ₁ , TiBP, t-Bu-P ₂ and t-Bu-P ₄ . Other catalysts include BF ₃ Et ₂ O used in cationic ring-opening polymerization.

The organic solvent may be selected from various organic compounds such as toluene, tetrahydrofuran (THF), sodium hydroxide, N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, A solvent may be included.

A step S120 of performing ring-opening polymerization by mixing the soft segment A, the catalyst, the organic solvent, and the glycidyl derivative,

Then, a monomer is added to the soft segment A to perform ring-opening polymerization.

The monomer refers to a glycidyl derivative, and the glycidyl derivative can be synthesized by the following formula 3.

[Formula 3]

Naphthylglycidyl ether (NG) is synthesized by ring-opening polymerization of epichlorohydrin and a naphthyl initiator containing a hydroxy group in the presence of a base.

Next, ring-opening polymerization of the soft segment A and naphthylglycidyl ether (NG) in the presence of a base results in the synthesis of PNG-PTG-PNG as shown in the following formula (4).

[Formula 4]

Thus, the glycidyl derivative is represented by the ring-opening polymerization represented by the following formula (2).

(2)

N 'is an integer of 1 to 1000, and R ₃ is a substituted or unsubstituted aryl group.

The method for producing a triblock copolymer according to the second embodiment of the present invention comprises the steps of synthesizing soft segment A (S210) and a step S220 of condensing polymerization by mixing soft segment A, a catalyst, an organic solvent and an isocyanate derivative ).

The step S210 of synthesizing the soft segment A is as described above in the first embodiment.

A step S220 of condensing polymerization by mixing the soft segment A, the catalyst, the organic solvent and the isocyanate derivative,

The soft segment A is mixed with an isocyanate derivative and subjected to condensation polymerization. The isocyanate group (-N = C = O) undergoes a condensation polymerization with a hydroxyl group (-OH) existing at the end of the soft segment A to form a urethane. The condensation polymerization can be carried out at about 50 to 90 占 폚, but is not limited thereto.

Hard segment B containing a urethane group in the main chain can be synthesized by adding a dialcohol (BDO) in which an alcohol group is bonded to both ends of a urethane-formed polymer. It can be confirmed that the finally synthesized triblock copolymer is a triblock copolymer having a B-A-B configuration by a single bond between the soft segment A and the hard segment B.

The triblock copolymer according to the second embodiment can be synthesized by the method of the following formula (5).

[Formula 5]

The hard segment B containing a urethane group in the main chain is represented by the following general formula (3).

(3)

Thus, in the present invention, liquid PTEGGE (poly (triethylene glycol glycidyl ether)) can be converted into a solid by preparing a triblock copolymer in which a soft segment block and a hard segment block are repeated from an epoxy derivative by catalytic polymerization . In addition, ion conduction can be increased by ion channel formation due to the phase separation of soft segment block A and hard segment block B.

Specific examples of the triblock copolymer and the production method thereof using the catalyst polymerization will be described as follows.

1 shows NMR results of TG and NG monomers according to the present invention. NMR peaks of TG (triethylene glycol glycidyl ether) synthesized in the above formula 1 and NG (napthyl glycidyl ether) monomer synthesized in the formula 3 are shown.

2 shows NMR results of PTG and PNG-PTG-PNG triblock copolymer according to the present invention. The NMR peaks of the PTG synthesized in the formula 2 and the PNG-PTG-PNG copolymer synthesized in the formula 4 are shown. A part of the peak of PTG coincides with the peak of TG, and the peak of PTG can be confirmed at the peak of PNG-PTG-PNG.

FIG. 3 is a graph showing the molecular weight distribution of PTG according to the present invention. Table 1 shows the bi-directionality of PTG polymer through ring-opening polymerization of TG under t-Bu-P ₄ catalyst.

[Table 1]

** M _{n, theo} : number average molecular weight, D _: molecular weight distribution, conv. (%): Degree of polymerization

Referring to FIG. 3 and Table 1, the polymerization degree of TG was controlled to 30, 60, and 90, and the theoretical molecular weight and the actually measured molecular weight were matched. Through the ring-opening polymerization, it is possible to confirm the result that the polymer chain having an activating group at the terminal is controlled and grown, and the living performance and controllability of the polymerization can be confirmed.

Figure 4 is a bi-directional copolymer triblock through the ring-opening polymerization of TG and NG under a graph showing the molecular weight distribution of the PNG-PTG-PNG triblock copolymer according to the present invention, Table 2 t-Bu-P ₄ catalyst This is the result.

[Table 2]

** f _{wt, PNG} : weight ratio of PNG

By adding NG to the synthesized PTG, a triblock copolymer having a B-A-B configuration can be produced. It can be confirmed that the molecular weight and the weight fraction of NG are controlled according to the ratio of the block.

FIG. 5 shows TGA and DSC analysis results of the PEO, PTG, PNG and PNG-PTG-PNG triblock copolymers according to the present invention. _{(Conditions: PEO (M n = 20.0 kDa} ), PTG (M n = 21.6 kDa) and PNG-PTG-PNGs (M n = 23.930.9 kDa, f wt, PNG = 9.2, 16.7, 22.7 and 28.6 wt%) (b) cooling at 250 ° C to -85 ° C at a cooling rate of 10 ° C / min in a nitrogen atmosphere, (c) cooling to -85 ° C in a nitrogen atmosphere, in ℃ to 250 ℃ temperature was raised at a heating rate of 10 ℃ / min, (d) PEO (M n = 20.0 kDa), PTG (M n = 21.6 kDa) and PNG-PTG-PNGs (M n = 23.930.9 kDa, _{f wt, PNG = 9.2, 16.7} , 22.7 and the LiTFSI to 28.6 wt%) [Li] / [O] = a mixture of 0.05 ratio was raised to a temperature rising rate of 10 ℃ / min from -60 ℃ to 0 ℃)

Referring to the TGA analysis results, it is shown that the triblock copolymer is stable within the temperature range up to 300 < 0 > C. From this, it can be predicted that it will be stable within the operating temperature range of the battery.

Also, referring to the results of the DSC analysis, it can be confirmed that the glass transition temperature (about -65 DEG C) necessary for efficiently transferring ions is obtained. In addition, it was confirmed that NG can be used as a hard block through high glass transition temperature and crystallization temperature.

6 shows XRD analysis results of PNG, PNG-PTG-PNG triplet block copolymer according to the present invention. For the (condition (b) ABA triblock copolymer, PNG -PTG-PNG (M n = 23.930.9 kDa, f wt, PNG = 9.2, 16.7, 22.7 and 28.6 wt%)) The DSC analysis PNG-PTG-PNG , It was difficult to confirm the crystallization temperature due to the low content of PNG. As a result of XRD analysis, the crystallinity of the PNG block was confirmed and it can be used as a hard block.

Figure 7 (a) is an ion conductivity measurement results of the copolymer PEO, PTG, PNG-PTG- PNG triblock according to the invention _{(conditions:. PEO (M n = 20.0} kDa), PTG (M n = 21.6 kDa) and 3 times at 30 to 80 ° C) and PNG-PTG-PNG ( M _n = 23.930.9 kDa, f _{wt, PNG} = 9.2, 16.7, 22.7 and 28.6 wt%

Through ionic conductivity measurement, it shows high ion conductivity value in low temperature range compared to conventional PEO. Also, as the ratio of the PNG block increases, it is confirmed that the ion conductivity increases even though the number of the PTG blocks conducting the ions decreases.

7 (b) is a VTF plot of the PEO, PTG and PNG-PTG-PNG triple block copolymers according to the present invention. (The VTF plot results are shown in FIG. 5 (d) Calculated from the results.)

VTF plot was used to analyze the tendency of the ion conductivity to improve even though the ratio of PNG block increased. The slope of the graph is calculated as the activation energy (Ea) necessary to transfer the ions.

[Formula 6]

In the formula ^{_{6 E a (kJ · mol 1}} ) is the activation ^{energy, A (K 1/2 S · cm} 1) is the number of charge ^{carriers, R (J mol 1 · K} 1) is the gas constant, T ₀ (K ) = T _g 50K.

Table 3 below shows the results of ion conductivity and VTF plot of FIG.

[Table 3]

Referring to Table 3, it can be seen that as the ratio of the PNG block increases, Ea decreases and the efficiency of transferring ions by transferring ions with lower energy is improved.

FIGS. 8 and 9 are TEM images showing the fine phase separation structure of the PNG-PTG-PNG triplet block copolymer according to the present invention. FIG. PNG ₇ -PTG ₉₆ -PNG ₇ (f _{wt, PNG} = 9.2 wt%), (c, d) PNG ₁₂ -PTG ₉₇ -PNG ₁₂ (f _{wt, PNG} = 16.7 wt% (e, f) PNG ₁₅ -PTG ₉₄ -PNG ₁₅ (f _{wt, PNG} = 22.7 wt%) and (g, h) PNG ₁₈ -PTG ₁₀₇ -PNG ₁₈ (f _{wt, PNG} = 28.6 wt%) films with LiTFSi 30 wt% stained with RuO ₄ )

As the ratio of the PNG block increases, a clear ion channel is formed, and the ion conductivity is increased by transferring ions through the formed ion channel while the triblock copolymer has a self-assembling property.

10 is a graph showing the electrical characteristics of the PNG-PTG-PNG triplet block copolymer according to the present invention. (Conditions: (a) PNG ₇ -PTG ₉₆ -PNG ₇ (f _{wt, PNG} = 9.2 wt% _{b) PNG 12 -PTG 97 -PNG 12} (f wt, PNG = 16.7 wt%), (c) PNG 15 -PTG 94 -PNG 15 (f wt, PNG = 22.7 wt%), (d) PNG 18 -PTG [Li] / [O] = 0.05, 30 wt%) containing _107- PNG ₁₈ (f _{wt, PNG} = 28.6 wt%

The remaining samples show electrochemically stable results up to 4V except for (a) where the ratio of the PNG block is the lowest.

11 shows NMR and GPC analysis results of PAGE according to the present invention. To introduce the functional group, poly (allyl glycidyl ether) (PAGE) having a vinyl group introduced at the end of the side chain was synthesized and its NMR and GPC were measured. In the NMR, the hydrogen peak of the ethyl group and the hydrogen peak corresponding to the initiator can be observed.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is to be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims (16)

A soft segment A represented by the following general formula (1); And
And hard segment B comprising a hard segment B or a urethane group (-NHCOO-) represented by the following formula (2)
Wherein the soft segment A and the hard segment B have a BAB type arrangement by a single bond.
[Chemical Formula 1]

M is an integer of 1 to 1000,
R ₁ and R ₂ are ethylene glycol compounds.
(2)

N 'is an integer of 1 to 1000,
And R < ₃ > is a substituted or unsubstituted aryl group.
delete delete The method according to claim 1,
Wherein R < ₃ > is naphthalene.
The method according to claim 1,
Wherein the hard segment B containing a urethane group (-NHCOO-) in the main chain is represented by the following formula (3).
(3)

Wherein n is an integer of 1 to 1000
The method according to claim 1,
Wherein the ratio of the segment A to the total repeating units in the triblock copolymer is larger than the ratio of the segment B to the total repeating units.
The method according to claim 6,
Wherein the mixing ratio of the segment A: segment B to the total repeating units in the above-mentioned triblock copolymer is 1: 0.1 to 1: 0.5 in a molar ratio.
The method according to claim 1,
Wherein the triblock copolymer is a triblock copolymer for a lithium battery electrolyte.
(a) synthesizing a soft segment A represented by the following formula (1); And
(b) ring-opening polymerization by mixing the soft segment A, the catalyst, and the organic solvent with the glycidyl derivative,
The glycidyl derivative is synthesized by ring-opening polymerization to a hard segment B represented by the following formula (2)
Wherein the soft segment A and the hard segment B have a BAB type arrangement by a single bond.
[Chemical Formula 1]

M is an integer of 1 to 1000,
R ₁ and R ₂ are ethylene glycol compounds.
(2)

N 'is an integer of 1 to 1000,
And R < ₃ > is a substituted or unsubstituted aryl group.
(a) synthesizing a soft segment A represented by the following formula (1); And
(b) condensing and polymerizing the soft segment A, the catalyst, and the organic solvent with an isocyanate derivative,
The isocyanate derivative is synthesized by condensation polymerization as a hard segment B containing a urethane group in the main chain,
Wherein the soft segment A and the hard segment B have a BAB type arrangement by a single bond.
[Chemical Formula 1]

M is an integer of 1 to 1000,
R ₁ and R ₂ are ethylene glycol compounds.
delete 11. The method according to claim 9 or 10,
Wherein in step (a), ring-opening polymerization is carried out by mixing an ethylene glycol monomer containing a glycidyl group, an initiator represented by the following formula (4), a catalyst and an organic solvent.
[Chemical Formula 4]

delete 10. The method of claim 9,
Wherein R < ₃ > is naphthalene.
11. The method of claim 10,
Wherein the hard segment B containing a urethane group (-NHCOO-) in the main chain is represented by the following formula (3).
(3)

Wherein n is an integer of 1 to 1000
11. The method according to claim 9 or 10,
Wherein the catalyst comprises at least one of t-Bu-P ₁ , TiBP, t-Bu-P ₂ and t-Bu-P ₄ .

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