KR102044841B1 - Water soluble polyamic acid salt, preparing method thereof, and polyimide formed therefrom - Google Patents

Abstract

화학식 1에서, X₁, Ar₁, Ar₂, R₁ 내지 R₅, Y+는 상세한 설명에서 정의된 바와 같다. 일구현예에 따른 수용성 폴리아믹산염은 화합물 내에 하이드록시(OH)구조가 존재하여 물에 용해되는 특성을 가지며 이를 이용하여 제조된 중합체들 및/또는 열적 이미드화를 진행한 폴리이미드 필름은 내열성 및 화학적/기계적 내구성이 개선된다.The present invention provides a water-soluble polyamic acid salt represented by the following formula (1), a method for preparing the same, and a polyimide formed therefrom.
[Formula 1]

In Formula 1, X ₁ , Ar ₁ , Ar ₂ , R ₁ to R ₅ , Y + are as defined in the detailed description. The water-soluble polyamic acid salt according to one embodiment has a hydroxy (OH) structure in the compound to dissolve in water, and the polymers and / or thermal imidized polyimide films prepared using the same have heat resistance and Chemical / mechanical durability is improved.

Description

Water soluble polyamic acid salt, preparing method etc, and polyimide formed therefrom}

The present invention relates to a novel water-soluble polyamic acid salt, a method for producing the same, and a polyimide film obtained therefrom.

As a composite material, polyimide may be used for sizing to improve the properties of carbon fiber. When using an organic solvent, the sizing solvent that does not affect the fiber may dissolve the fiber itself or affect the surface of the fiber. The choice is important. In addition, dispersants are used to disperse carbon nanotubes (CNT) and graphene oxide (GO), which are widely used as composite materials, in the matrix, which increases the degree of dispersion but may be a defect in the composite material itself. Development of a dispersant that does not affect its properties is required.

In addition, it is essential to develop a carbon fiber sizing agent having high heat resistance in order to manufacture a carbon fiber composite material using a high heat resistance polymer. Generally used epoxy sizing agent has a property of decomposing at 300 ℃ or more has a limitation in the production of a polymer composite material having a melting temperature of 300 ℃ or more. Therefore, it is necessary to develop a polyamic acid that is soluble in water rather than an organic solvent, which has a great feature of being environmentally friendly, and provides the advantage of coating polyimide on fibers without the use of an organic solvent in high heat sizing of carbon fibers. It can be used as a dispersant for CNT or GO. Since water has the characteristics of a salt having charge while using water as a basic solvent, it is possible to increase the degree of dispersion and has the advantage of being used as a polymer matrix as a dispersant rather than an additive which may be a defect as a composite material. In addition, it is essential to develop a polyimide sizing agent having high heat resistance in order to produce a carbon fiber composite material using a polymer having high heat resistance.

Embodiments of the present invention to provide a water-soluble polyamic acid salt and its manufacturing method.

In another embodiment of the present invention to provide a polyimide obtained from the water-soluble polyamic acid salt.

According to one aspect, a water-soluble polyamic acid salt represented by the following Chemical Formula 1 is provided.

[Formula 1]

In Formula 1, X ₁ represents a single bond or represents oxygen (O), sulfur (S), sulfur monoxide (SO), sulfur dioxide (SO ₂ ), selenium (Se), an alkylene group of C1-C10, and a divalent C5-. C20 is selected from the group consisting of carbon rings, a is an integer of 0, 1, 2 or 3, Ar ₁ and Ar ₂ are each independently selected from the group consisting of Formulas 1-1 to 1-3,

[Formula 1-1] [Formula 1-2] [Formula 1-3]

In Formulas 1-1 to 1-3, R ₁ to R ₄ are each independently selected from the group consisting of hydrogen (H), a hydroxyl group (OH), and an alkyl group of C1 to C30, and R ₅ is represented by the following Formula 2-1 A tetravalent group selected from the group represented by or a tetravalent C4 to C30 cycloalkyl group or a C3 to C30 tetravalent cycle containing 1 to 10 or more heteroatoms selected from N, O, F, S and P An alkyl group,

[Formula 2-1]

* Represents a binding region, Y ⁺ may be represented by the following formula (3) or (4),

[Formula 3]

는 치환된 또는 비치환된 2 내지 30개의 탄소 원자를 포함하는 3원 내지 21원 고리(membered ring)이며, *는 결합 영역을 나타내며, R₆은 수소, C1 내지 C10의 알킬기, C6-C20의 아릴기 또는 C2-C20의 헤테로아릴기를 나타내며, n은 1 내지 20의 정수이고,In formula 3,

Is a 3 to 21 membered ring containing 2 to 30 carbon atoms substituted or unsubstituted, * represents a bonding region, R ₆ represents hydrogen, an alkyl group of C1 to C10, a C6-C20 group An aryl group or a C2-C20 heteroaryl group, n is an integer from 1 to 20,

[Formula 4]

delete

In Formula 4, a and b are each independently an integer of 2 to 20, c is an integer of 1 to 20, R ₇ is an alkyl group of C1 to C10, an aryl group of C6-C20 or a heteroaryl group of C2-C20 And * represents a bonding region, and the degree of polymerization of the polyamic acid salt is an integer of 10 to 1,000.

According to the other side A method for producing a polyamic acid salt is prepared by reacting a polyamic acid with a compound represented by the following Chemical Formula 7 or a compound represented by the following Chemical Formula 8 to produce the aforementioned water-soluble polyamic acid salt.

[Formula 7]

는 치환된 또는 비치환된 2 내지 30개의 탄소 원자를 포함하는 3원 내지 21원 고리(membered ring)이며, R₆은 수소, C1 내지 C10의 알킬기, C6-C20의 아릴기 또는 C2-C20의 헤테로아릴기를 나타내며, n은 1 내지 20의 정수이고,In Formula 7,

Is a 3 to 21 membered ring containing 2 to 30 carbon atoms which is substituted or unsubstituted, R ₆ is hydrogen, an alkyl group of C1 to C10, an aryl group of C6-C20 or of C2-C20 Heteroaryl group, n is an integer from 1 to 20,

 [Formula 8]

In formula (8), a and b are each independently an integer of 2 to 20, c is an integer of 1 to 20, R ₇ is an alkyl group of C1 to C10, an aryl group of C6-C20 or a heteroaryl group of C2-C20 Where * represents a binding region and a, b, c, R ₇ are as defined in formula (4).

According to yet another aspect, there is provided a polyimide, which is the imidation reaction product of the polyamic acid salt described above.

The polyamic acid salt and / or polyimide is used as a dispersant or carbon fiber sizing agent of a carbonaceous material.

The water-soluble polyamic acid salt according to one embodiment is an environmentally friendly material having excellent solubility in water and is useful as a sizing agent for carbon fibers or a dispersant for carbon-based materials. Polyimides obtained from such water-soluble polyamic acids are structurally very stable, have very high chemical stability, and can exhibit excellent heat resistance and chemical / mechanical durability.

1 is a nuclear magnetic resonance (NMR) analysis of the polyamic acid, 4-hydroxy-1-methylpiperidine (HMP) according to Example 1 and the water-soluble polyamic acid salt prepared according to Example 2 It is shown.
FIG. 2 shows the results of NMR analysis of polyamic acid, bis (2-hydroxyethyl) amino-2-propanol (BHP) according to Example 1, and a water-soluble polyamic acid salt prepared according to Example 2.
3 is a graph showing the results of Fourier Transform Infrared (FT-IR) analysis of the polyamic acid according to Example 1 and the water-soluble polyamic acid salts prepared according to Examples 2 and 3. FIG.
Figure 4 is a graph showing the results of thermogravimetric analysis (TGA) of the polyamic acid according to Example 1 and the water-soluble polyamic acid salt prepared according to Examples 2 and 3.

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. Embodiments of the present invention have been described with reference to the accompanying drawings, which are described for purposes of illustration, whereby the technical idea of the present invention and its configuration and application are not limited.

The water-soluble polyamic acid salt represented by following formula (1) is provided.

[Formula 1]

In Formula 1, X ₁ represents a single bond or represents oxygen (O), sulfur (S), sulfur monoxide (SO), sulfur dioxide (SO ₂ ), selenium (Se), an alkylene group of C1-C10, C6-C20 Selected from the group consisting of an arylene group and a bivalent C5-C20 carbon ring,

a is an integer of 0, 1, 2 or 3,

Ar ₁ and Ar ₂ are each independently selected from the group consisting of Formulas 1-1 to 1-3,

[Formula 1-1] [Formula 1-2] [Formula 1-3]

In Formulas 1-1 to 1-3, R ₁ to R ₄ are each independently selected from the group consisting of hydrogen (H), a hydroxyl group (OH), and an alkyl group of C1 to C30.

R ₅ includes 1 to 10 heteroatoms selected from one of a tetravalent group selected from the group represented by the following Chemical Formula 2-1 or a tetravalent C4 to C30 cycloalkyl group or N, O, F, S and P C3 to C30 is a tetravalent cycloalkyl group,

[Formula 2-1]

* Represents a bonding region,

Y ⁺ may be represented by the following Chemical Formula 3 or 4,

[Formula 3]

는 치환된 또는 비치환된 2 내지 30개의 탄소 원자를 포함하는 3원 내지 21원 고리(membered ring)이며, *는 결합 영역을 나타내며, R₆은 수소, C1 내지 C10의 알킬기, C6-C20의 아릴기 또는 C2-C20의 헤테로아릴기를 나타내며, n은 1 내지 20의 정수이고,In Formula 3,

Is a 3 to 21 membered ring containing 2 to 30 carbon atoms substituted or unsubstituted, * represents a bonding region, R ₆ represents hydrogen, an alkyl group of C1 to C10, a C6-C20 group An aryl group or a C2-C20 heteroaryl group, n is an integer from 1 to 20,

[Formula 4]

In Formula 4, a and b are each independently an integer of 2 to 20, c is an integer of 1 to 20, R ₇ is an alkyl group of C1 to C10, an aryl group of C6-C20 or a heteroaryl group of C2-C20 And * represents a bonding region, and the degree of polymerization of the polyamic acid salt is n an integer of 10 to 1,000.

The alkylene group of C ₁ -C 10 in X ₁ of Formula 1 is, for example, —C (CH ₃ ) ₂ —, or —CH ₂ . And the carbon ring of divalent C5-C20 may be, for example, a divalent group of the following structural formula.

,

,

The arylene group of C 6 -C 20 in X ₁ of Formula 1 is, for example, a phenylene group.

Formula 1 may be represented by, for example, Formula 1a.

 [Formula 1a]

In Formula 1, X ₁ , Ar ₁ , Ar ₂ , R ₁ to R ₄ are the same as defined in Formula 1.

In Formula 3, n is an integer of 1 to 20, for example, an integer of 1 to 3.

The compound represented by the formula (3) or (4) used as Y ⁺ has a hydroxyl group is very excellent solubility in water.

Y + is selected from the group represented by the following Chemical Formula 3a or 4a.

[Formula 3a]

In formula (3a), * represents a binding region,

[Formula 4a]

delete

In Formula (4a), * represents a binding region.

The Y ⁺ may be a group represented by the following Chemical Formula 3-1 or 4-1.

[Formula 3-1] [Formula 4-1]

delete

The water-soluble polyamic acid salt is a polymer represented by the following formula (5) or (6). The degree of polymerization of the following polymers is an integer of 10 to 1,000, for example an integer of 10 to 100.

[Formula 5]

delete

[Formula 6]

The water-soluble polyamic acid salt according to one embodiment may be obtained by reacting a polyamic acid with a compound represented by Formula 7 or Formula 8.

Polyamic acid according to one embodiment is prepared through a polymerization reaction of a diamine compound and dione hydride as a polyimide precursor.

[Formula 7]

In Formula 7, R ₆ and n are as defined in Formula 3.

[Formula 8]

In Formula 8, a, b, c, and R ₇ are as defined in Formula 4.

The polyamic acid salt is charged by the reaction of the compound of Formula 7 or 8, which is an amine, with the carboxyl group of the polyamic acid, and a hydroxy (OH) structure is present to obtain a water-soluble polyamic acid salt dissolved in water.

이 피페리딘과 같은 지방족 고리 화합물이다. 이러한 화합물을 이용하여 얻어진 폴리아믹산염은 아민으로서 1,2-디메틸이미다졸과 같이

이 방향족 고리인 화합물을 이용하여 얻어진 폴리아믹산과 비교하여 물과 유기용매에 대한 용해도 특성이 개선된다. 화합물 8의 화합물은 적어도 하나의 2차 하이드록시기를 갖는 화합물이다. 아민으로서 적어도 하나의 2차 하이드록시기를 갖는 화합물을 이용하여 얻은 폴리아믹산은 아민으로서 트리에탄올아민을 사용하여 얻은 폴리아믹산염과 비교하여 물과 유기용매에 대한 용해도 특성이 개선된다.Compound of Formula 7

It is an aliphatic ring compound such as piperidine. Polyamic acid salts obtained using such compounds are amines such as 1,2-dimethylimidazole.

The solubility characteristic in water and an organic solvent is improved compared with the polyamic acid obtained using this aromatic ring compound. Compound 8 is a compound having at least one secondary hydroxy group. The polyamic acid obtained using a compound having at least one secondary hydroxy group as an amine has improved solubility characteristics in water and organic solvents compared to the polyamic acid salt obtained using triethanolamine as an amine.

The compound of formula 7 is, for example, a group represented by formula 7a.

[Formula 7a]

 [Formula 8a]

The diamine compound used in preparing the polyamic acid may be used as long as it is commonly used in the art. For example, one or more selected from the compounds represented by Formula 9 may be used.

[Formula 9]

In an exemplary embodiment, the dione hydride is not particularly limited and may be used as long as all the dione hydrides commonly available in the art. It may be one or more selected from compounds represented by the formula (10).

[Formula 10]

In Formula 10, R ₅ may be defined the same as R ₅ in formula (I).

The polyamic acid may be, for example, a polyamic acid represented by Formula 3 below.

[Formula 11]

In Formula 11, Ar and R are as defined in Formula 1, the degree of polymerization is an integer of 10 to 1000.

The polymerization reaction of the diamine compound and dione hydride described above is performed by adding a solvent to the diamine compound and dione hydride under an inert gas atmosphere. As the solvent, for example, N-methylpyrrolidone, tetrahydrofuran and the like are used.

An inert gas atmosphere is formed using argon, nitrogen, or the like.

In the polymerization reaction described above, reaction conditions such as temperature may vary depending on the type of diamine compound and acid dihydrate used. For example, the polymerization reaction can be carried out, for example, in the range of 25 ° C to 150 ° C.

Polyamic acid and polyamic acid salt according to one embodiment has a number average molecular weight of 10,000 to 500,000 g / mol.

In an exemplary embodiment, the polyimide film may be prepared by imidating the polyamic acid salt.

Examples of the imidization include a method of carrying out dehydration ring by heating and a method of carrying out dehydration ring using a dehydrating agent. The method of carrying out dehydration ring by heating performs imidation by implementing at high temperature of 300 degreeC-400 degreeC, for example.

The dehydration ring using a dehydrating agent is carried out at a temperature of 200 ° C. or lower to perform imidization. It is also possible to carry out using a catalyst such as an acid and a base together with the dehydrating agent. For example, an organic acid such as p-hydroxyphenylacetic acid is used as the acid catalyst, and isoquinoline, triethylamine, pyridine, 1,4-diazabicyclo [2.2.2] octane, etc. are used as the base catalyst. .

Thermal methods can be used for imidization.

The water-soluble polyamic acid salt according to one embodiment has a hydroxy (OH) structure in the compound and has a property of dissolving in water, and the polymer and / or thermal imidization polyimide film prepared by using the same polyimide film It can exhibit heat resistance and chemical / mechanical durability that is not different from mead.

In an exemplary embodiment, the water soluble polyamic acid salt may reduce the total weight of the water soluble polyamic acid polymer from 27% to 39% at about 800 ° C. compared to the total weight of the polyamic acid polymer at room temperature.

The water-soluble polyamic acid salt is excellent in the solubility property when the solution is dissolved in water or an organic solvent at 25 ° C. for 5 hours so that a cloudy precipitate or gel does not form and is well dissolved. In addition, the water-soluble polyamic acid salt does not form a precipitate or a gel when present in an aqueous solution of 10% by weight for 5 hours at 50 ℃ excellent solubility characteristics. In addition, the water-soluble polyamic acid polymer is excellent in storage stability because the precipitate left at 25 ° C. for 12 hours has a viscosity of 10% or less, for example, 8% or less, for example, 5 to 7% of the initial viscosity. Do.

Polyimides obtained from the polyamic acid salts described above are structurally very stable, have very high chemical stability, exhibit excellent heat resistance and chemical / mechanical durability and are easy to manufacture.

Since carbon fiber has a small elongation and a weak property, it is easy to cause fluff due to mechanical friction and the like, and also lacks wettability with respect to the matrix resin. For this reason, it is difficult for the carbon fiber used as a reinforcing material to fully exhibit the outstanding property. In order to improve this, the carbon fiber is processed with the sizing agent. Polyamic acid salt and polyimide according to one embodiment is used as a sizing agent of the carbon fiber provides the advantage that the polyimide can be coated on the fiber without the use of an organic solvent in the high heat sizing of the carbon fiber.

In addition, the polyamic acid salt and / or polyimide according to one embodiment may be used as a dispersant for carbon-based materials such as carbon nanotubes (CNT), graphene, and graphene oxide (GO). Since water has the characteristics of a salt having charge while using water as a basic solvent, it can increase the degree of dispersion and can be used as a polymer matrix as a dispersant rather than an additive which may be a defect as a composite material.

As described above, the polyamic acid salt and the polyimide obtained therefrom according to one embodiment can be used as a dispersant of a carbon-based material such as CNT or GO, it is possible to develop a polymer composite material having a high dispersion as a dispersant as a polymer matrix . And it can provide a carbon fiber composite material using a polyamic acid salt and a polyimide obtained therefrom according to an embodiment.

Looking at the definition of the substituent used in the formula of the present specification are as follows.

Alkyl group refers to a group of fully saturated branched or unbranched (or straight or linear) hydrocarbons. Non-limiting examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, isopentyl, neopentyl, iso-amyl, n-hexyl, 3- Methylhexyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl, and the like. At least one hydrogen atom of the alkyl may be a halogen atom, a C1-C20 alkyl group substituted with a halogen atom (eg CF ₃ , CH ₃ CF ₂ , CH ₂ F, CCl _3, etc.), a C1-C20 alkoxy group, C2-C20 Alkoxyalkyl group, hydroxy group, nitro group, cyano group, amino group, alkylamino group, amidino group, hydrazine, hydrazone, carboxyl group or salt thereof, sulfonyl group, sulfamoyl group, sulfonic acid group or salt thereof, phosphoric acid or salt thereof Or C1-C20 alkyl group, C2-C20 alkenyl group, C2-C20 alkynyl group, C1-C20 heteroalkyl group, C6-C20 aryl group, C6-C20 arylalkyl group, C6-C20 heteroaryl group , C7-C20 heteroarylalkyl group, C6-C20 heteroaryloxy group, C6-C20 heteroaryloxyalkyl group or C6-C20 heteroarylalkyl group can be substituted.

By cycloalkyl group is meant an aliphatic hydrocarbon comprising at least one ring. At this time, the alkyl group is as described above. Heterocycloalkyl group refers to a cycloalkyl group containing one or more heteroatoms selected from N, O, P or S. The cycloalkyl group is as described above.

Halogen atoms include fluorine, bromine, chlorine, iodine and the like.

Aryl groups are used alone or in combination to mean aromatic hydrocarbons containing one or more rings. Aryl groups also include groups in which an aromatic ring is fused to one or more cycloalkyl rings. Non-limiting examples of the aryl include phenyl group, naphthyl group, tetrahydronaphthyl group and the like. At least one hydrogen atom in the aryl group may be substituted with the same substituent as in the alkyl group described above.

Heteroaryl group refers to a monocyclic or bicyclic organic compound comprising at least one heteroatom selected from N, O, P or S, wherein the remaining ring atoms are carbon. The heteroaryl group may include, for example, 1-5 heteroatoms, and may include 5-10 ring members. The S or N may be oxidized to have various oxidation states.

The monocyclic heteroaryl group is, for example, thienyl group, furyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, thiazolyl group, isothiazolyl group, 1,2,3-oxadiazolyl group, 1,2 , 4-oxadiazolyl group, 1,2,5-oxadiazolyl group, 1,3,4-oxadiazolyl group, 1,2,3-thiadiazolyl group, 1,2,4-thiadiazolyl Group, 1,2,5-thiadiazolyl group, 1,3,4-thiadiazolyl group, isothiazol-3-yl group, isothiazol-4-yl group, isothiazol-5-yl group, oxazole -2-yl group, oxazol-4-yl group, oxazol-5-yl group, isoxoxazol-3-yl group, isoxazol-4-yl group, isoxazole-5-yl group, 1,2,4-tria Zol-3-yl, 1,2,4-triazol-5-yl, 1,2,3-triazol-4-yl, 1,2,3-triazol-5-yl, tetrazolyl, p Lead-2-yl, pyrid-3-yl, 2-pyrazine-2yl, pyrazin-4-yl, pyrazine-5-yl, 2-pyrimidin-2-yl, 4-pyrimidin-2-yl, Or a 5-pyrimidin-2-yl group.

Heteroaryl includes when the heteroaromatic ring is fused to one or more aryls, cycloaliphatic, or heterocycles.

Examples of bicyclic heteroaryl include indolyl, isoindolyl, indazolyl, indolizinyl, purinyl, quinolizinyl, and quinoli Quinolinyl, isoquinolinyl, and the like. At least one hydrogen atom of such heteroaryl may be substituted with the same substituent as in the alkyl group described above.

Alkylene, arylene, heteroarylene, cycloalkylene, heterocycloalkylene means a group in which one hydrogen is substituted with a radical in alkyl, aryl, heteroaryl, cycloalkyl, heterocycloalkyl.

Hereinafter, the present invention will be described with reference to the following examples, but the present invention is not limited only to the following examples.

Example  One: Polyamic acid  Produce

Completely dissolve 4,4'-oxydianiline (ODA) in a dimethylacetamide solvent in a 70 ml vial, add pyromellitic dihydride (PMDA) to it, and stir at room temperature (25 ° C) for about 24 hours. To prepare a polyamic acid solution having a solid content of 10 wt%. Thereafter, the polyamic acid solution was precipitated in water to obtain a polyamic acid precipitate represented by Chemical Formula 9a.

[Formula 9a]

The weight average molecular weight of the polyamic acid represented by the formula (9a) is 100,000 g / mol, and the intrinsic viscosity is 0.9 dl / g.

Example  2: water soluble Polyamic acid  Produce

Dissolve 4,4'-oxydianiline (ODA) in a dimethylacetamide (DMAc) solvent in a 70 ml vial, add pyromellitic diohydride (PMDA), and stir at room temperature for about 24 hours. A wt% polyamic acid solution was prepared. Then, 4-hydroxy-1-methylpiperidine (HMP) was added thereto, stirred for about 6 hours or more, and then precipitated in acetone to obtain a water-soluble polyamic acid precipitate represented by Chemical Formula 5.

[Formula 5]

delete

The degree of polymerization of the water-soluble polyamic acid salt represented by the formula (5) satisfies the weight average molecular weight 1,000 ~ 500,000, the intrinsic viscosity is 0.9 dl / g or more.

Example  3: water soluble Polyamic acid  Produce

Dissolve 4,4'-oxydianiline (ODA) in a dimethylacetamide (DMAc) solvent in a 70 ml vial, and then add pyromellitic diohydride (PMDA) and stir at room temperature for about 24 hours. A polyamic acid solution having a solid content of 10 wt% was prepared. Thereafter, 1-bis (2-hydroxyethyl) amino-2-propanol (BHP) was added thereto, and the resultant obtained after stirring for about 6 hours or more was precipitated in acetone to prepare a water-soluble polyamic acid precipitate represented by Chemical Formula 6.

[Formula 6]

The intrinsic viscosity of the water-soluble polyamic acid salt represented by the formula (6) was 0.9 dl / g or more, and the weight average molecular weight was 100,000 g / mol.

Comparative example  1: water soluble Polyamic acid  Produce

The same procedure as in Example 2 was conducted except that 1-methylpiperidine (MPP) was used instead of 4-hydroxy-1-methylpiperidine (HMP).

Evaluation example  1: NMR analysis

NMR analysis of the polyamic acid according to Example 1 and the water-soluble polyamic acid salts prepared according to Examples 2 and 3 were performed, and the results are shown in FIGS. 1 and 2, respectively.

1 shows the results of NMR analysis of polyamic acid (PAA) according to Example 1, 4-hydroxy-1-methylpiperidine (HMP) and water-soluble polyamic acid salt (PAS) prepared according to Example 2. 2 shows the results of NMR analysis of polyamic acid (PAA) according to Example 1, bis (2-hydroxyethyl) amino-2-propanol (BHP) and water-soluble polyamic acid salt (PAS) prepared according to Example 2. It is shown.

1 and 2, when comparing the peak of the polyamic acid and the peak of the added amine, the peak of the amic acid from a to f, and the peak of the amine added from 1 to 5 shows a peak of the amine The structure of the polyamic acid polymer can be confirmed.

Evaluation example  2: FT-IR analysis

The FT-IR graphs of the polyamic acid according to Example 1 (PAA) and the water soluble polyamic acid salt prepared according to Example 2 (PAS_HMP) and the water soluble polyamic acid salt prepared according to Example 3 (PAS_BHP) were measured, Indicated.

In the graph of FIG. 3, the peak of 1700 cm ^-1 of the carbonyl functional group of the polyamic acid can be confirmed, and the peak of the amine of 1610 and 1330 cm ^-1 was found without the peak of the carbonyl functional group in the water-soluble polyamic acid salt. .

Evaluation example  3: TGA  analysis

Polyamic acid according to Example 1 (PAA) and water-soluble polyamic acid salt prepared according to Example 2 (PAS_HMP) and water-soluble polyamic acid salt prepared according to Example 3 (PAS_BHP), polyamic acid salt of Comparative Example 1 (PAS_MPP TGA analysis was performed for thermal analysis of) and is shown in FIG. 4.

Referring to Figure 4, the polyamic acid after the heat treatment at 800 ℃ the carbonization yield of about 39% and the carbonization yield of the water-soluble polyamic acid salt of Example 2 is about 27%, the water-soluble polyamic acid salt prepared according to Example 3 ( The carbonization yield of PAS_BHP) was 32%, and the carbonization yield of polyamic acid salt (PAS_MPP) prepared according to Comparative Example 1 was 35%.

Evaluation example  4: solubility characteristics

Solubility analysis of the water-soluble polyamic acid salt prepared according to Example 2, Example 3, Comparative Example 1, Comparative Example 2 and Comparative Example 3 was carried out and shown in Table 1 below. Solubility analysis examined whether 1 g of water-soluble polyamic acid salt was dissolved in 100 ml of the solvent of Table 1 at 25 ° C. In Table 1, ++ means that it was dissolved at room temperature, + means that it was dissolved when given a heat of 40 degrees or more, and-means not dissolved even when given heat.

menstruum Example 2 (HMP) Example 3 (BHP) Comparative Example 1 (MPP) Water ++ ++ - DMSO ++ ++ ++ DMF + ++ + DMAc ++ ++ ++ NMP ++ ++ ++

As can be seen in Table 1, the water-soluble polyamic acid salts of Examples 2 and 3 were well dissolved at room temperature with respect to organic solvents such as DMSO, DMAc, and NMP, including water. You could see it completely melted by the heat. In addition, unlike the case of Comparative Example 1, the water-soluble polyamic acid of Examples 2 and 3 does not form precipitates or gels when present in an aqueous solution, and has excellent solubility characteristics.

On the other hand, the solubility characteristics of the polyamic acid salts of Comparative Examples 1 to 3 were lower than those of the polyamic acid salts of Examples 1-3.

Evaluation example  4: viscosity

The intrinsic viscosity of the polyamic acid obtained according to Example 1 and the polyamic acid salt obtained according to Examples 2 and 3 was measured at 30 ° C. using an obbel rod viscometer. Intrinsic viscosity measurement results are shown in Table 2 below.

division Intrinsic viscosity (dl / g) Example 1 0.9 Example 2 0.9 or more Example 3 0.9 or more

Intrinsic viscosity in Table 2 is for a polyamic acid dimethylacetamide solution in which each sample is dissolved in dimethylacetamide (DMAc) at a concentration of 0.5 g / dL.

In addition, the polyamic acid powders of Examples 2 and 3 were dissolved in water at a concentration of 0.5 g / dL to measure the viscosity, and the results are shown in Table 3 below.

division Viscosity (dl / g) Example 2 0.17 Example 3 0.08

Referring to Table 3, the viscosity of the aqueous solution of the water-soluble polyamic acid polymers of Examples 2 and 3 was found.

In addition, after changing the aqueous polyamic acid solution of Examples 2 and 3 at 25 ℃ for 12 hours, the viscosity change was examined. As a result, it was found that no precipitates or gels were formed at 10% or less of the initial viscosity, for example, 8% or less, for example, 5 to 7%, and thus the storage stability was very excellent.

The embodiments of the present invention described above should not be construed as limiting the technical spirit of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention as long as it will be apparent to those skilled in the art.

Claims (7)

Water-soluble polyamic acid salt represented by the following formula (1):
[Formula 1]

In Formula 1, X ₁ represents a single bond or is selected from the group consisting of oxygen (O), sulfur (S), an alkylene group of C 1 -C 10 and a carbon ring of divalent C 5 -C 20,
a is 1,
Ar ₁ and Ar ₂ are each independently selected from the group consisting of Formulas 1-1 to 1-3,
[Formula 1-1] [Formula 1-2] [Formula 1-3]

In Formulas 1-1 to 1-3, R ₁ to R ₄ are each independently selected from the group consisting of hydrogen (H), a hydroxyl group (OH), a C1 to C30 alkyl group, and a fluorinated C1 to C30 alkyl group;
R ₅ includes one to 10 tetravalent groups selected from the group represented by the following formula 2-1 or one or more heteroatoms selected from tetravalent C4 to C30 cycloalkyl group or N, O, F, S and P C3 to C30 is a tetravalent cycloalkyl group,
[Formula 2-1]

Y ⁺ is one selected from the group represented by the following formula (3a),
[Formula 3a]

In Formula (3a), * represents a bonding region, and the degree of polymerization of the polyamic acid salt is an integer of 10 to 1,000. delete The water-soluble polyamic acid salt of claim 1, wherein Y ⁺ is a group represented by the following Chemical Formula 3-1.
[Formula 3-1]

The water-soluble polyamic acid salt of claim 1, wherein the polyamic acid salt is a polymer represented by the following Chemical Formula 5.
[Formula 5]

A method for preparing a water-soluble polyamic acid salt by reacting a polyamic acid with one selected from the compounds represented by the following Chemical Formula 7a to produce the water-soluble polyamic acid salt according to claim 1, 3 or 4.
[Formula 7a]

The polyimide which is the imidation reaction product of the polyamic acid salt of Claim 1, 3 or 4. 7. The polyimide of claim 6, wherein the polyimide is used as a dispersant or carbon fiber sizing agent of a carbonaceous material.

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