JP2018123295A - Aromatic polyamide and surface modifier - Google Patents

Abstract

An aromatic polyamide that can be used for surface modification of inorganic fine particles is provided. An aromatic polyamide represented by the following formula (1): (In the formula, X represents an alkylene group having 1 to 10 carbon atoms, R independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R1 and R2 represent Each independently represents an alkyl group having 1 to 10 carbon atoms, R 3 independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms, Ar represents 1, 3 represents a 3-phenylene group or a 1,4-phenylene group, n represents an integer of 2 or more, and k represents an integer of 1 to 3.) [Selection] None

Description

  The present invention relates to an aromatic polyamide, and more specifically to an aromatic polyamide that can be used for surface modification of inorganic fine particles.

  In order to improve the heat resistance, mechanical properties, and electrical properties of organic materials, hybrid materials (nanocomposites) in which inorganic fine particles such as silica gel and titanium oxide are mixed with organic polymers have been well studied. However, since organic materials and inorganic materials have very different properties in the first place, there is a problem that the amount of inorganic fine particles that can be added is limited, and it is not only difficult to disperse the added inorganic fine particles in the organic material, but also the time. As a result, there is a problem that the added inorganic fine particles aggregate in the organic material.

Therefore, in order to solve these problems, the surface of inorganic fine particles has been modified with an organic low molecular weight compound or an organic polymer. In particular, in the case of modification with an organic polymer, (1) a start site is introduced into the inorganic surface and living polymerization is performed therefrom, or (2) a functional group (—Si (OR)) capable of binding to an inorganic substance at the living polymer terminal. ₃ , —PO ₃ H, —CO ₂ H, —SH, etc.) are introduced and reacted with the surface of the inorganic fine particles.

  However, since living polymerization is limited to addition polymerization and ring-opening polymerization, the resulting polymer is an aliphatic polymer with little heat resistance. In this case, even if inorganic fine particles are mixed with an organic material to increase the heat resistance, the surface-modified aliphatic polymer is thermally decomposed first, and thus has the same problem as a material mixed with inorganic fine particles that are not surface-modified. Another major problem is that the modified aliphatic polymer is hardly mixed with the condensed aromatic polymer having high heat resistance.

  In order to solve these problems, the surface of the fine particles may be modified with a condensed aromatic polymer having excellent heat resistance. However, since the condensed aromatic polymer can be obtained only by polycondensation, the approaches (1) and (2) utilizing the characteristics of living polymerization have been impossible.

J. Am. Chem. Soc. 122, pp. 8313-8314 (2000)

  This invention is made | formed in view of such a situation, and it aims at providing the aromatic polyamide which can be utilized for the surface modification etc. of inorganic fine particles.

In the aromatic polyamide polymerization method (refer to Non-Patent Document 1) by chain condensation polymerization (CGCP), which is a polycondensation living polymerization that has been developed so far, the present inventors have obtained using an initiator having an unsaturated bond. As a result of the introduction of -Si (OR) ₃ that reacts with the inorganic surface by utilizing the unsaturated terminal thus obtained, it has been found that an aromatic polyamide that can be used as a modifier for the surface of the inorganic fine particles can be obtained. Was completed.

That is, the present invention provides the following aromatic polyamide and surface modifier.
1. An aromatic polyamide represented by the following formula (1).
(In the formula, X represents an alkylene group having 1 to 10 carbon atoms, R independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms, R ¹ and R ² independently represents an alkyl group having 1 to 10 carbon atoms, R ³ independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms, Ar represents A 1,3-phenylene group or a 1,4-phenylene group, n represents an integer of 2 or more, and k represents an integer of 1 to 3)
2. 1 aromatic polyamide represented by the following formula (2).
(In the formula, R, R ¹ , R ² , Ar and n are the same as described above.)
3. 1 or 2 aromatic polyamide in which R ¹ and R ² are each independently a methyl group or an ethyl group.
The surface modifier containing the aromatic polyamide in any one of 4.1-3.
5. Inorganic fine particles that are surface-modified with any one of aromatic polyamides 1 to 3.
An organic / inorganic hybrid material comprising 6.5 inorganic fine particles and an organic matrix resin.
A film produced using the organic / inorganic hybrid material of 7.6.
8). An aromatic polyamide represented by the following formula (3).
(In the formula, R ¹ and R ² each independently represent an alkyl group having 1 to 10 carbon atoms, Ar represents a 1,3-phenylene group or a 1,4-phenylene group, and n represents 2 (It represents the integer above.)
9. 8. An aromatic polyamide of 8, wherein R ¹ and R ² are each independently a methyl group or an ethyl group.

  ADVANTAGE OF THE INVENTION According to this invention, the aromatic polyamide which can be utilized as a modifier of the inorganic fine particle surface can be provided. It is expected to develop organic / inorganic hybrid materials in which the surface of inorganic fine particles such as silica and boron nitride is modified using this aromatic polyamide and mixed with heat-resistant polymers such as polyimide to further improve heat resistance and mechanical properties. it can.

It is a scanning electron microscope (SEM) photograph (3,000 times) of the cross section of the hybrid film produced in Example 4-6.

The aromatic polyamide of the present invention is represented by the following formula (1).

In formula (1), X represents an alkylene group having 1 to 10 carbon atoms. R represents a C1-C10 alkyl group or a C6-C20 aryl group mutually independently. R ¹ and R ² each independently represent an alkyl group having 1 to 10 carbon atoms. R ³ independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. Ar represents a 1,3-phenylene group or a 1,4-phenylene group. n represents an integer of 2 or more. k represents an integer of 1 to 3.

  Specific examples of the alkylene group having 1 to 10 carbon atoms include methylene group, ethylene group, methylethylene group, trimethylene group, propylene group, methylpropylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, Although an octamethylene group, a decamethylene group, etc. are mentioned, Especially a C1-C5 alkylene group is preferable, a C1-C3 alkylene group is more preferable, and a trimethylene group is much more preferable.

  Specific examples of the alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, 1-methyl-n-butyl group, 2-methyl-n-butyl group, 3-methyl-n-butyl group, 1,1-dimethyl-n-propyl group, 1,2-dimethyl-n -Propyl group, 2,2-dimethyl-n-propyl group, 1-ethyl-n-propyl group, cyclopentyl group, n-hexyl group, 1-methyl-n-pentyl group, 2-methyl-n-pentyl group, 3-methyl-n-pentyl group, 4-methyl-n-pentyl group, 1,1-dimethyl-n-butyl group, 1,2-dimethyl-n-butyl group, 1,3-dimethyl-n-butyl group 2,2-dimethyl-n-butyl group 2,3-dimethyl-n-butyl group, 3,3-dimethyl-n-butyl group, 1-ethyl-n-butyl group, 2-ethyl-n-butyl group, 1,1,2-trimethyl-n -Propyl group, 1,2,2-trimethyl-n-propyl group, 1-ethyl-1-methyl-n-propyl group, 1-ethyl-2-methyl-n-propyl group, cyclohexyl group, n-heptyl group , N-octyl group, n-nonyl group, n-decyl group and the like.

Specific examples of the aryl group having 6 to 20 carbon atoms include phenyl group, α-naphthyl group, β-naphthyl group, o-biphenylyl group, m-biphenylyl group, p-biphenylyl group, 1-anthryl group, and 2-anthryl group. Group, 9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group and the like. Among these, as R, R ¹ and R ² , a methyl group and an ethyl group are preferable. R ³ is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, n -A pentyl group or the like is more preferable.

  k represents an integer of 1 to 3, preferably 2 or 3, and more preferably 3. Although n will not be specifically limited if it is an integer greater than or equal to 2, The integer of 2-100 is preferable.

  As aromatic polyamide represented by Formula (1), what is represented by following formula (2) is preferable.

(In the formula (2), R, R ¹ , R ² , Ar and n are the same as described above.)

  The number average molecular weight (Mn) of the aromatic polyamide of the present invention is preferably 1,000 to 200,000, and more preferably 1,000 to 20,000. In the present invention, Mn is a measured value in terms of polystyrene by gel permeation chromatography (GPC).

  The aromatic polyamide of the present invention can be obtained using, as a raw material, an aromatic polyamide represented by the following formula (3) obtained by the method of Non-Patent Document 1.

(Wherein R ¹ , R ² , Ar, and n are the same as described above.)

  An aromatic polyamide represented by the formula (1) is obtained by subjecting an aromatic polyamide having a vinyl group represented by the formula (3) and an alkoxysilyl group-containing thiol compound to a radical addition reaction. In this case, the reaction ratio between the aromatic polyamide represented by the formula (3) and the alkoxysilyl group-containing thiol compound is not particularly limited, but in consideration of the reaction efficiency, etc., 1 mol of the aromatic polyamide of the formula (3) On the other hand, although a thiol compound can be about 1-100 mol, 5-50 mol is preferable and 10-30 mol is more preferable.

  Specific examples of the alkoxysilyl group-containing thiol compound include 3- (trimethoxysilyl) propanethiol and 3- (triethoxysilyl) propanethiol.

  The polymerization initiator is not particularly limited as long as it can be decomposed by heat or a reducing substance to generate radical species. For example, azo compounds such as 2,2′-azobisisobutyronitrile, benzoyl And peroxides such as peroxide, tert-butyl perbenzoate, tert-butyl hydroperoxide, di-tert-butyl peroxide, cumene hydroperoxide, and the like. These may be used alone or in combination of two or more.

  The reaction can also be performed in an organic solvent. Any solvent can be used as long as it dissolves the aromatic polyamide and does not interfere with the polymerization reaction. For example, aliphatic hydrocarbons such as pentane, hexane, heptane, octane, and cyclohexane; diethyl ether, diisopropyl Ethers such as ether, dibutyl ether, cyclopentyl methyl ether, tetrahydrofuran, and 1,4-dioxane; aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, and anisole; halogens such as chloroform, dichloromethane, dichloroethane, and carbon tetrachloride And nitriles such as acetonitrile and propionitrile. Of these, nitriles are preferable, and acetonitrile is particularly preferable.

  The reaction temperature is preferably about 50 to 150 ° C, more preferably about 60 to 100 ° C. The reaction time is usually about 1 to 120 hours. After completion of the reaction, the desired product can be obtained by post-treatment according to a conventional method and, if necessary, purification such as reprecipitation.

  Since the aromatic polyamide of the present invention has an alkoxysilyl group at the terminal, the surface of the inorganic fine particles, the surface of the inorganic substrate, etc. can be modified using this alkoxysilyl group. Since the aromatic polyamide is excellent in heat resistance, the aromatic polyamide of the present invention is used as a surface treatment agent for inorganic materials, and also by using a resin excellent in heat resistance such as polyimide and polyamide as an organic matrix, Development of organic / inorganic hybrid materials with excellent heat resistance and mechanical properties can be expected.

Hereinafter, the present invention will be described more specifically with reference to synthesis examples, preparation examples, comparative preparation examples, examples and comparative examples, but the present invention is not limited to the following examples. Each reagent and each measuring apparatus used in the examples are as follows.
[reagent]
DMF: dimethylformamide DMAP: N, N-dimethyl-4-aminopyridine EDCI: 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide THF: tetrahydrofuran AIBN: 2,2′-azobisisobutyronitrile [GPC ]
Device: Shodex GPC-101 (manufactured by Showa Denko KK)
Column: Two Shodex KF-804l (Showa Denko Co., Ltd.)
Column temperature: 40 ° C
Solvent: THF 1 mL / min Detector: UV (254 nm), RI
Calibration curve: Standard polystyrene [ ¹ H-NMR]
Equipment: JEOL ECA-500 and ECA-600
[TG-DTA]
Equipment: Seiko Instruments Inc. TG / DTA 6200
[Scanning Electron Microscope (SEM)]
Device: JSM-7400F (manufactured by JEOL Ltd.)

[1] Synthesis of aromatic polyamide [Example 1] Synthesis of aromatic polyamide 1 (1) Synthesis of compound 1

To a 200 mL eggplant flask, 20.0015 g (0.106 mol) of ethyl 3-aminobenzoate, 13 mL (0.249 mol) of acetonitrile and 132 mL of dry ethanol were added and stirred at room temperature for 1 hour. Thereafter, 2.00 g of 5% palladium carbon was added and stirred for 6 days under a hydrogen atmosphere. After adding methylene chloride and filtering through celite, and distilling off the solvent under reduced pressure, the crude product was recrystallized (good solvent: methylene chloride, poor solvent: hexane) to obtain Compound 1 as a white solid. (Yield 18.8231 g, Yield 80%). As a result of TG-DTA measurement, the melting point of Compound 1 was 48.8-51.9 ° C. The results of ¹ H-NMR measurement are shown below.
¹ H-NMR (600MHz, CDCl ₃ ) δ 7.36 (d, J = 7.6Hz, 1H), 7.27 (s, 1H), 7.22 (t, J = 7.9Hz, 1H), 6.77 (d, J = 7.9Hz , 1H), 4.35 (q, J = 7.2Hz, 2H), 3.67 (br s, 1H), 3.20 (q, J = 7.2Hz, 2H), 1.38 (t, J = 7.2Hz, 3H), 1.26 ( t, J = 7.2 Hz, 3H).

(2) Synthesis of compound 2

To a 50 mL eggplant flask, 2.516 g (16.9 mmol) of 4-vinylbenzoic acid and 1.7142 g (18.2 mmol) of phenol were added. To a separately prepared 30 mL eggplant flask, 15 mL of dry DMF and 2.3020 g (18.8 mmol) of DMAP were added and added to the 50 mL eggplant flask. The mixture was stirred at 0 ° C for 20 minutes, 4.2065 g (21.9 mmol) of EDCI was added, and the mixture was stirred again at 0 ° C for 16 hours. Then, the mixture was stirred at room temperature for 22 hours, water was added to stop the reaction, and the mixture was extracted three times with diethyl ether. The organic phase was extracted once with 1 mol / L hydrochloric acid, once with a saturated aqueous sodium bicarbonate solution, and further saturated with chloride. Washed once with aqueous sodium solution. Then, it dried with anhydrous magnesium sulfate and filtered, and the solvent was distilled off under reduced pressure to obtain Compound 2 as a white solid (crude yield 3.168 g, crude yield 95%). As a result of TG-DTA measurement, the melting point of Compound 2 was 94.7-97.9 ° C. The results of ¹ H-NMR measurement are shown below.
¹ H-NMR (600MHz, CDCl ₃ ) δ 8.16 (d, J = 8.2Hz, 2H), 7.53 (d, J = 8.2 Hz, 2H), 7.43 (t, J = 7.9Hz, 2H), 7.27 (t , J = 7.6Hz, 1H), 7.22 (d J = 8.2Hz, 2H), 6.79 (dd, J = 17.9 and 11.0Hz, 1H), 5.91 (d, J = 17.5Hz, 1H), 5.43 (d, J = 11.0 Hz, 1H).

(3) Synthesis of compound 3

  The 50 mL eggplant flask was heated and dried with a heat gun under reduced pressure, and then purged with argon and returned to room temperature. Under a nitrogen stream, 11.2 mL (11.2 mmol) of 1 mol / L LiHMDS in THF was added and stirred at 0 ° C. for 20 minutes. Compound 2 (0.407 g, 2.02 mmol) dissolved in 5.2 mL of dry THF was added, and 1.9408 g (10.0 mmol) of Compound 1 dissolved in 12.6 mL of dry THF was added dropwise over 1 hour under a nitrogen stream. . The mixture was stirred at 0 ° C. for 5 hours, quenched with saturated aqueous ammonium chloride solution, extracted with methylene chloride three times, the organic phase washed with water three times, dried over anhydrous magnesium sulfate, filtered, and reduced in pressure. The solvent was distilled off under reduced pressure to obtain compound 3 as a pale yellow solid (crude yield 2.0631 g, crude yield 88%). As a result of GPC measurement, Mn = 1,200 and dispersity (Mw / Mn) = 1.17.

(4) Synthesis of aromatic polyamide 1

In a pressure-resistant reaction tube, 15 mL of dry toluene, 0.29 mL (1.52 mmol) of 3- (trimethoxysilyl) -1-propanethiol, 0.4509 g (0.153 mmol) of Compound 3 and 12.6 mg (0.0767 mmol) of AIBN were added. In addition, freeze deaeration was performed 4 times. After stirring at 60 ° C. for 2 days, the solvent was distilled off under reduced pressure to obtain a yellow viscous liquid (crude yield 0.7503 g, crude yield 155%). The crude product was purified by precipitation (good solvent: methylene chloride, poor solvent: hexane) to obtain aromatic polyamide 1 as a light yellow solid (yield 0.3941 g, yield 82%). As a result of the GPC measurement, Mn = 2,100 and Mw / Mn = 1.14. The results of ¹ H-NMR measurement are shown below.
¹ H-NMR (600MHz, CDCl ₃ ) δ 7.84 (d, J = 7.9Hz, 1H), 7.73 (s, 1H), 7.29 (q, J = 7.9Hz, 1H), 7.18 (t, J = 7.9Hz , 1H), 4.35 (q, J = 7.2Hz, 2H), 3.68 (s, 2nH), 3.54 (s, 9H), 2.76 (t, J = 7.7Hz, 2H), 2.63 (t, J = 7.9Hz , 2H), 2.50 (t, J = 7.2Hz, 2H), 1.66 (quint, J = 7.6Hz, 2H), 1.34 (t, J = 7.2Hz, 3H), 1.00-0.84 (m, 3nH), 0.72 (t, J = 8.1Hz, 2H).

[Example 2] Synthesis of aromatic polyamide 2 (1) Synthesis of compound 4

In a 500 mL eggplant flask, dry THF 150 mL, methyl 4-aminobenzoate 113.422 g (75.0 mmol), octanal 10.5 mL (67.3 mmol), sodium triacetoxyborohydride 23.8462 g (113 mmol) and acetic acid 8.6 mL ( 150 mmol) was added and stirred at room temperature for 3 days. Thereafter, the reaction was stopped by adding a saturated aqueous sodium hydrogen carbonate solution, extracted three times with ethyl acetate, and then washed three times with a saturated aqueous sodium chloride solution. After drying over anhydrous magnesium sulfate, filtration was performed, and the solvent was distilled off under reduced pressure to obtain a crude product as a white solid (crude yield 18.3628 g, crude yield 93%). The crude product was recrystallized (methanol) to obtain compound 4 as a white solid (yield 9.0872 g, yield 46%). As a result of TG-DTA measurement, the melting point of Compound 4 was 88.6-91.8 ° C. The results of ¹ H-NMR measurement are shown below.
¹ H-NMR (500MHz, CDCl ₃ ) δ 7.85 (d, J = 8.6Hz, 2H), 6.53 (d, J = 8.9Hz, 2H), 4.08 (br s, 1H), 3.84 (s, 3H), 3.15 (q, J = 6.1Hz, 2H), 1.62 (quint, J = 7.2Hz, 2H), 1.39 (quint, J = 7.6Hz, 2H), 1.40-1.26 (m, 8H), 0.89 (t, J = 7.0Hz, 3H).

(2) Synthesis of compound 5

  The 50 mL eggplant flask was heated and dried with a heat gun under reduced pressure, replaced with argon, and returned to room temperature. Under a nitrogen stream, 5.2 mL (5.2 mmol) of 1 mol / L LiHMDS in THF was added and stirred at −10 ° C. for 45 minutes. To a 50 mL pear flask were added 1.3250 g (5.03 mmol) of Compound 4, 0.115 g (0.512 mmol) of Compound 2, and 5.2 mL of dry THF, and the mixture was added to the previous 50 mL eggplant flask under a nitrogen stream. The mixture was stirred at −10 ° C. for 4 hours, quenched with a saturated aqueous ammonium chloride solution, extracted three times with methylene chloride, and then the organic phase was washed three times with a 1 mol / L aqueous sodium hydroxide solution and washed with anhydrous magnesium sulfate. After drying and filtration, the solvent was distilled off under reduced pressure to obtain a yellow viscous liquid containing Compound 3 (crude yield 1.1919 g, crude yield 84%). As a result of the GPC measurement, Mn = 3,300 and Mw / Mn = 1.08.

(3) Synthesis of aromatic polyamide 2

In a pressure-resistant reaction tube, dry toluene 8 mL, 3- (trimethoxysilyl) -1-propanethiol 0.2 mL (1.07 mmol), compound 5 0.3238 g (0.0952 mmol) and AIBN 7.83 mg (0.0477 mmol) were added. In addition, freeze deaeration was performed three times. After stirring at 60 ° C. for 22 hours, the solvent was removed under reduced pressure to obtain a pale yellow viscous liquid (crude yield 0.5678 g, crude yield 165%). The crude product was purified by precipitation (good solvent: diethyl ether, poor solvent: hexane) to obtain aromatic polyamide 2 as a pale yellow solid (yield 0.0289 g, yield 8%). The results of ¹ H-NMR measurement are shown below.
¹ H-NMR (600MHz, CDCl ₃ ) δ 7.08-6.91 (m, 1nH), 6.76-6.69 (m, 1mH), 3.77 (s, 3H), 3.78-3.73 (m, 2nH), 3.50 (s, 9H ), 2.73 (s, 2H), 2.62 (s, 2H), 2.47 (q, J = 7.4Hz, 2H), 1.65 (quint, J = 8.0Hz 2H), 1.43 (s, 2nH), 1.28-1.11 ( m, 10nH), 0.79 (t, J = 6.8 Hz 3nH), 0.68 (t, J = 8.2Hz, 2H).

[2] Preparation of aromatic polyamide-modified silica sol [Example 3-1] Preparation of aromatic polyamide-modified silica sol 1 In a pressure resistant reaction tube, 0.1247 g (0.0584 mmol) of aromatic polyamide 1, 1.9 mL of methyl ethyl ketone and methyl ethyl ketone- Silica sol solution (MEK-ST-40, manufactured by Nissan Chemical Industries, Ltd.) 0.5010 g (silica content: 0.204 g) was added. After stirring at 60 ° C. for 5 hours, the solvent was distilled off under reduced pressure to obtain aromatic polyamide-modified silica sol 1 as a brown viscous solid (crude yield 0.369 g).

[Example 3-2] Preparation of silica sol solution (Z1) 0.30 g of aromatic polyamide-modified silica sol 1 was added to 2.7 g of DMAc to prepare a 10 mass% silica sol solution (Z1).

[Example 3-3] Preparation of aromatic polyamide-modified silica sol 2 An aromatic polyamide-modified silica sol was obtained as a brown viscous solid in the same manner as in Example 3-1, except that aromatic polyamide 2 was used.

[Example 3-4] Preparation of silica sol solution (Z2) 0.30 g of aromatic polyamide-modified silica sol 2 was added to 2.7 g of DMAc to prepare a 10 mass% silica sol solution (Z2).

[3] Synthesis of polyamic acid [Synthesis Example 1] Synthesis of polyamic acid (S1) 3.248 g (30 mmol) of p-phenylenediamine was dissolved in 88 g of DMAc. To the obtained solution, 8.751 g (30 mmol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was added and reacted at 23 ° C. for 24 hours under a nitrogen atmosphere. As a result of GPC measurement, the weight average molecular weight (Mw) of the obtained polyamic acid was 27,300, and Mw / Mn was 2.6.

[Synthesis Example 2] Synthesis of polyamic acid (S2) 2,962 g (19 mmol) of 2,2′-bis (trifluoromethyl) benzidine was dissolved in 88 g of DMAc. To the resulting solution was added 3.382 g (15 mmol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4.654 (4 mmol) of 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride. And reacted at 23 ° C. for 24 hours under a nitrogen atmosphere. As a result of GPC measurement, Mw of the obtained polyamic acid was 17,000, and Mw / Mn was 2.3.

[Synthesis Example 3] Synthesis of polyamic acid (S3) 3.867 g (19 mmol) of diaminodiphenyl ether was dissolved in 32 g of DMAc. To the resulting solution, 4.133 g (19 mmol) of pyromellitic dianhydride was added and reacted at 23 ° C. for 24 hours under a nitrogen atmosphere. As a result of GPC measurement, Mw of the obtained polyamic acid was 28,000, and Mw / Mn was 2.1.

[4] Production of hybrid film and evaluation thereof [Example 4-1]
To 6.0 g of polyamic acid (S1), 0.90 g of silica sol solution (Z1) was added and stirred at 23 ° C. for 3 hours to prepare a varnish. Thereafter, the varnish was applied onto a glass substrate with a bar coater to prepare a coating film having a thickness of 250 μm, and baked at 80 ° C. for 1 hour and at 300 ° C. for 1 hour.
The obtained film had no cloudiness and was a beautiful yellow film. Moreover, when this film was peeled from the glass substrate with a cutter, it was easily peeled off. The peeled film showed strong self-supporting properties.

[Example 4-2]
A varnish and a film were produced under the same conditions as in Example 4-1, except that the amount of polyamic acid (S1) used was 2.4 g. The obtained film had no cloudiness and was a beautiful yellow film. Moreover, when this film was peeled from the glass substrate with a cutter, it was easily peeled off. The peeled film showed strong self-supporting properties.

[Example 4-3]
A varnish and a film were produced under the same conditions as in Example 4-1, except that 2.4 g of polyamic acid (S2) was used instead of polyamic acid (S1). The obtained film had no cloudiness and was a beautiful yellow film. Moreover, when this film was peeled from the glass substrate with a cutter, it was easily peeled off. The peeled film showed strong self-supporting properties.

[Example 4-4]
A varnish and a film were produced under the same conditions as in Example 4-2, except that the baking was performed at 80 ° C. for 1 hour and at 230 ° C. for 1 hour. The obtained film had no cloudiness and was a beautiful yellow film. Moreover, when this film was peeled from the glass substrate with a cutter, it was easily peeled off. The peeled film showed strong self-supporting properties.

[Example 4-5]
The same as Example 4-1 except that 3.0 g of polyamic acid (S3) was used instead of polyamic acid (S1) and 0.90 g of silica sol solution (Z2) was used instead of silica sol solution (Z1). A varnish and a film were prepared under the conditions. The obtained film had no cloudiness and was a beautiful yellow film. Moreover, when this film was peeled from the glass substrate with a cutter, it was easily peeled off. The peeled film showed strong self-supporting properties.

[Example 4-6]
A varnish and a film were produced under the same conditions as in Example 4-1, except that the amount of polyamic acid (S1) used was 0.8 g. The obtained film had no cloudiness and was a beautiful yellow film. Moreover, when this film was peeled from the glass substrate with a cutter, it was easily peeled off. The peeled film showed strong self-supporting properties. Moreover, as a result of confirming the cross section by SEM, the sol was dispersed finely throughout the film. An SEM image is shown in FIG.

[Comparative Preparation Example 1] Preparation of sol solution (HZ1) To 30 g of MEK-ST-40 sol solution (silica content: 20 g), 30 g of DMAc was added and methyl ethyl ketone was distilled off using an evaporator to remove the surface unmodified sol A solution (HZ1) was prepared.

[Comparative Example 1]
To 10.0 g of polyamic acid (S1), 0.3 g of the sol solution (HZ1) was added and stirred at 23 ° C. for 3 hours to prepare a varnish. Then, this varnish was apply | coated with the bar coater on the glass substrate, the coating film with a film thickness of 250 micrometers was produced, and it baked at 80 degreeC for 1 hour and 300 degreeC for 1 hour.
The obtained film had no cloudiness and was a beautiful yellow film, but could not be peeled off.

[Comparative Example 2]
A varnish and a film were produced in the same manner as in Comparative Example 2 except that the amount of the sol solution (HZ1) used was 3 g. The obtained film was cloudy and could not be peeled off.

Claims (9)

An aromatic polyamide represented by the following formula (1).
(In the formula, X represents an alkylene group having 1 to 10 carbon atoms, R independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms, R ¹ and R ² independently represents an alkyl group having 1 to 10 carbon atoms, R ³ independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms, Ar represents A 1,3-phenylene group or a 1,4-phenylene group, n represents an integer of 2 or more, and k represents an integer of 1 to 3) The aromatic polyamide according to claim 1, which is represented by the following formula (2).
(In the formula, R, R ¹ , R ² , Ar and n are the same as described above.) The aromatic polyamide according to claim 1 or 2, wherein R ¹ and R ² are each independently a methyl group or an ethyl group.   The surface modifier containing the aromatic polyamide of any one of Claims 1-3.   Inorganic fine particles surface-modified with the aromatic polyamide according to any one of claims 1 to 3.   An organic / inorganic hybrid material comprising the inorganic fine particles according to claim 5 and an organic matrix resin.   A film produced using the organic / inorganic hybrid material according to claim 6. An aromatic polyamide represented by the following formula (3).
(In the formula, R ¹ and R ² each independently represent an alkyl group having 1 to 10 carbon atoms, Ar represents a 1,3-phenylene group or a 1,4-phenylene group, and n represents 2 (It represents the integer above.) The aromatic polyamide according to claim 8, wherein R ¹ and R ² are each independently a methyl group or an ethyl group.