JPH07126526A - Polyaniline composite molded article and method for producing the same - Google Patents

Abstract

(57) [Summary] [Object] To provide a polyaniline composite molded article in which a dopant is hardly desorbed by water or a polar solvent and can maintain stable conductivity, and a method for producing the same. [Structure] The polyaniline composite molded article has the following general formula (I): (In the formula, m and n are integers of 0 or more, and m / (n
+ M) = 0 to 1, m + n = 10 to 5000. ) The number average molecular weight of the structural unit represented by
0000 polyaniline and a carboxyl group-containing polymer formed from one or more α-ethylenically unsaturated carboxylic acids. This polyaniline molded article is produced by impregnating a polyaniline molded article with α-ethylenically unsaturated carboxylic acid and polymerizing in the polyaniline molded article.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interpenetrating composite molding of polyaniline and an .alpha.-ethylenically unsaturated carboxylic acid polymer and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, polyaniline has been used as a new electronic material and a conductive material, for example, as a battery electrode material, an antistatic agent, an electromagnetic wave shielding material, a photoelectric conversion element, an optical memory,
Applications to a wide range of fields such as functional elements such as various sensors, display elements, various hybrid materials, transparent conductors, various terminal devices, etc. are being studied. However, in general, polyaniline has a highly developed π-conjugated system, so that the main chain of the polymer is rigid and interaction between molecular chains is strong, and many strong hydrogen bonds exist between the molecular chains. Since it is insoluble in the organic solvent and does not melt even when heated, it has a great drawback that it has poor moldability and cannot be processed into a film or the like. For this purpose, for example, a base material having a desired shape such as a fiber of a polymer material or a porous body is impregnated with a monomer, and the monomer is polymerized by contact with an appropriate polymerization catalyst or by electrolytic oxidation to form a conductive composite. Or in the presence of a thermoplastic polymer powder,
A similar composite material is obtained by polymerizing the monomers. On the other hand, by devising the polymerization catalyst and reaction temperature, N-methyl-
It has also been proposed to synthesize polyaniline which is soluble only in 2-pyrrolidone (M. Abe et al .; J. C.
hem. Soc. Chem. Commun. , 198
9, 1736). However, this polyaniline also
It is almost insoluble in other general-purpose organic solvents, and its application range is limited. Further, it is known that when this soluble polyaniline is gelled in N-methyl-2-pyrrolidone and this is molded, a very tough film is obtained, but it becomes brittle due to dope (O. Oka et al. .; Sy
nth. Met. 55-57 (1993) 999-10
04).

Further, polyaniline is doped with an acceptor dopant to form 10 ^-3 to 10 S /
It exhibits a high conductivity of cm. Examples of the dopant include halogen compounds such as iodine, bromine, chlorine and iodine trichloride,
Protonic acids such as sulfuric acid, hydrochloric acid, nitric acid, perchloric acid, and borofluoric acid, various salts of the protic acids, aluminum trichloride, iron trichloride, molybdenum chloride, antimony chloride, Lewis acids such as arsenic pentafluoride, acetic acid , Organic acids such as trifluoroacetic acid, benzenesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid and camphor sulfonic acid, polymeric acids such as polyethylene sulfonic acid, polyethylene carboxylic acid, polyacrylic acid and polystyrene sulfonic acid, Various compounds can be mentioned. However, when these dopants are catalytically or electrochemically doped as conventionally known, when the doped polyaniline is immersed in a solvent in which those dopants are well dissolved,
These dopants are easily dedoped and their conductivity is lost. For example, in the case of a polyaniline film doped with hydrochloric acid, when it is immersed in water for 2 hours, its conductivity decreases from 11 S / cm to 10 ⁻⁵ S / cm or less. Also, in the case of a polyaniline film doped with dodecylbenzene sulfonic acid, when it is immersed in chloroform for 2 hours, its conductivity is 1 S / cm.
To 10 ⁻⁵ S / cm or less. In the case of a polyaniline film doped with polyacrylic acid, when it is immersed in water for 4 hours, its conductivity becomes 0.1 S / c.
m to 10 ^-5 S / cm or less.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation in the prior art. That is, a first object of the present invention is to provide a polyaniline composite molded body in which a dopant is hard to be desorbed by water or a polar solvent and can maintain stable conductivity, and a manufacturing method thereof. The second object of the present invention is to
It is an object of the present invention to provide a composite molded body that suppresses a decrease in strength in a conductive state and a method for manufacturing the same.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has used a polymer as an acid serving as a dopant and converts it into a state of an interpenetrating complex with polyaniline. By doing so, they have not been dedoped by a solvent, can maintain stable conductivity, and can suppress a decrease in strength due to doping, and have completed the present invention.

The polyaniline composite molded article of the present invention has the following general formula (I):

[Chemical 2] (In the formula, m and n are integers of 0 or more, and m / (n
+ M) = 0 to 1, m + n = 10 to 5000. ) The number average molecular weight of the structural unit represented by
And a carboxyl group-containing polymer formed from one or more α-ethylenically unsaturated carboxylic acids. In the polyaniline composite molded article of the present invention, the ratio of the carboxyl group of the carboxyl group-containing polymer to the nitrogen atom of polyaniline is preferably 1: 0.2 to 1: 1.5 in molar ratio.

The polyaniline composite molded article of the present invention is
After impregnating one or more α-ethylenically unsaturated carboxylic acid into a polyaniline molded article made of polyaniline having a number average molecular weight of 2000 to 500,000, which comprises the structural unit represented by the general formula (I), It can be produced by polymerizing an α-ethylenically unsaturated carboxylic acid in a polyaniline molded body. In that case, the molar ratio of the carboxyl group of the carboxyl group-containing polymer to the nitrogen atom of polyaniline is 1: 0.2 to 1:
It is preferable to use both such that the ratio becomes 1.5.

The polyaniline used here may be produced by any method as long as it is soluble in N-methyl-2-pyrrolidone, but ammonium bisulfate or the like is used as an oxidizing agent, and aniline is used at low temperature. For example, -2
Soluble polyaniline obtained by oxidative polymerization at a temperature in the range of 0 to 50 ° C. and treating this aniline oxidation polymer with aqueous ammonia is preferably used. The soluble polyaniline obtained is N-methyl-2-pyrrolidone (N
MP) and N, N-dimethylacetamide (DMA
It is soluble in amide solvents such as c), but almost insoluble in other general-purpose organic solvents such as chloroform and tetrahydrofuran.

In the present invention, the soluble polyaniline has a number average molecular weight of 2000 to 500000 [GPC (N-
Methyl-2-pyrrolidone solvent) and have a polystyrene-equivalent number average molecular weight], and preferably in the range of 5,000 to 250,000. When the number average molecular weight of polyaniline is lower than 2000, the flexibility of the polyaniline molded product used for production is impaired, and it becomes difficult to obtain a self-supporting film, fiber or other molded product. On the other hand, if it exceeds 500000,
The solubility in a solvent becomes low, which is not preferable in terms of preparation and processing of a polyaniline molded article used for production.

The polyaniline obtained as described above is formed into a desired shape by, for example, a method of dissolving in NMP to form a cast film, gelling and processing into a formed body. Alternatively, the sheet-shaped polyaniline obtained in the electrolytic polymerization method may be used instead. However, in this case, the electrolytically polymerized polyaniline needs to be sufficiently dedoped. The polyaniline molded body obtained by any of these methods is impregnated with one or more α-ethylenically unsaturated carboxylic acids,
The α-ethylenically unsaturated carboxylic acid is incorporated as a dopant into the polyaniline molded body. The impregnation can be carried out by immersing it in an α-ethylenically unsaturated carboxylic acid, or by exposing it to its vapor for several hours. The incorporation of α-ethylenically unsaturated carboxylic acid as a dopant into the matrix of the polyaniline molded product can be confirmed by a change in weight or a change in conductivity. By strictly measuring the weight change, it is possible to accurately know the ratio of the nitrogen atom of the polyaniline to the carboxylic acid group, and therefore the ratio of the polyaniline to the carboxyl group-containing polymer in the final composite molded article, It can be controlled at this stage. Moreover, the conductivity of polyaniline before doping is 10 ⁻¹⁰ to 10 ⁻⁸ S /
cm, but as doping (incorporation of α-ethylenically unsaturated carboxylic acid) proceeds, 1 to 10 ⁻³ S / cm
Rise to a degree. Further, when dipping in the liquid phase, it is possible to accelerate the uptake of α-ethylenically unsaturated carboxylic acid by allowing a small amount of water to coexist.

In the present invention, as the α-ethylenically unsaturated carboxylic acid, any carboxylic acid having a double bond at the α-position can be used. Specifically, acrylic acid, methacrylic acid, crotonic acid, 2-
Methyl-2-butenoic acid, 3-chloroacrylic acid, 3-chlorocrotonic acid, 2-pentenoic acid, 2-hexenoic acid, 2
-Octenic acid, cinnamic acid, p-nitrocinnamic acid and the like.

The α-ethylenically unsaturated carboxylic acid-doped polyaniline molded product obtained as described above is then heated. By this heating, the α-ethylenically unsaturated carboxylic acid present in the polyaniline molded body is thermally polymerized, and when one type of α-ethylenically unsaturated carboxylic acid is used, a homopolymer is formed and two or more types are formed. If used, a copolymer is formed. In order to polymerize the α-ethylenically unsaturated carboxylic acid present in the polyaniline molded body, irradiation with electromagnetic waves such as electron beams and ultraviolet rays can be used in addition to heat. Alternatively, it is also possible to impregnate a solution in which a radical initiator is dissolved into a polyaniline molded product doped with α-ethylenically unsaturated carboxylic acid, and radically polymerize by heating or irradiation with an electromagnetic wave such as an electron beam or an ultraviolet ray. . The α-ethylenically unsaturated carboxylic acid that is a dopant is present between the main chains of polyaniline and the polymerization reaction proceeds in the matrix, so that the main chain of the polyaniline and the carboxyl group-containing polymer are entangled with each other. , Form a mutually intrusive network. Therefore, even if it is dipped in water or a solvent, the dopant is not dissociated and dissolved in water or a solvent, so that it is not dedoped.

The polyaniline composite molded article of the present invention can be further doped with an acceptor dopant to have a high conductivity of about 10 ⁻³ to 10 S / cm. The dopant that can be used is not particularly limited, and any dopant can be used as long as it is used as a dopant when doping the polyaniline-based conductive polymer. Specific examples include iodine, bromine, chlorine, halogen compounds such as iodine trichloride, sulfuric acid, hydrochloric acid, nitric acid, perchloric acid, protic acid such as borofluoric acid, various salts of the protic acid, aluminum trichloride, Lewis acids such as iron trichloride, molybdenum chloride, antimony chloride, arsenic pentafluoride, organic acids such as acetic acid, trifluoroacetic acid, benzenesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, camphor sulfonic acid, polyethylene sulfone Examples thereof include various compounds such as acids, polyethylene carboxylic acids, polyacrylic acids, and polymeric acids such as polystyrene sulfonic acids. For how to dope these compounds,
There is no particular limitation, and any known method can be adopted. Generally, the polyaniline composite molded article may be brought into contact with the dopant compound, and can be treated in a gas phase or a liquid phase. Also, a method of electrochemically doping in the solution of the above-mentioned protonic acid or its salt can be used.

[0014]

EXAMPLES The present invention will be described below with reference to examples. Example 1 4.1 g of aniline and 21.9 g of concentrated hydrochloric acid were dissolved in water to prepare 1
It was made up to 00 ml and cooled to -5 ° C. Concentrated hydrochloric acid 21.9 g,
Dissolve 6.28 g of ammonium persulfate in water to 100 m
This solution was cooled to -10 ° C and slowly added dropwise to the above aniline solution, and stirring was continued at -10 ° C for 6 hours. The produced solid matter was filtered, thoroughly washed with water, and then dedoped with 1N ammonia water for 10 hours. It is dried thoroughly and the number average molecular weight is 1
2000 (measured in GPC and NMP, polystyrene-equivalent number average molecular weight) of polyaniline was obtained. This was used as a raw material for manufacturing the composite molded body described below. A 3 wt% NMP solution of the above polyaniline was prepared, cast on a glass substrate and dried at 150 ° C. to obtain a polyaniline film. The obtained polyaniline film was immersed in acrylic acid containing 1% by weight of water for 2 hours for impregnation.
The weight gain per gram of film was 0.8 g, which indicates that acrylic acid was doped at a molar ratio of 1: 1 with respect to nitrogen atoms of polyaniline. The electrical conductivity at this time was 0.02 Scm ⁻¹ . The doped polyaniline film was heated at 80 ° C. for 6 hours to obtain the polyaniline composite molded body of the present invention. The fact that acrylic acid was polymerized was measured by IR (1635 cm ⁻¹ derived from C═C bond).
Absorption disappears, and 2850 to 2950 derived from C--C bond
The absorption at cm ⁻¹ was increased). The conductivity is
It was 0.02 Scm ^-1 . Further, this conductivity did not change even when immersed in water or methanol.

Example 2 A 5 wt% NMP solution of polyaniline of Example 1 was stirred at room temperature for 2 hours to obtain a polyaniline gel. After pouring this gel into a mold and treating it at 80 ° C. for 2 hours, the soluble component was dissolved in N.
It was extracted with MP for 12 hours, further contracted with methanol and dried. Thereby, 10 × 50 × 2 mm block-shaped polyaniline was obtained. The obtained polyaniline block was impregnated with methacrylic acid containing 1% by weight of water for 2 hours. The weight increase per 1 g of the block was 1.1 g, which means that methacrylic acid was doped at a molar ratio of 1: 1.2 with respect to the nitrogen atom of polyaniline. The electrical conductivity at this time was 0.05 Scm ⁻¹ . The doped polyaniline block was heated at 80 ° C. for 6 hours to obtain the polyaniline composite molded body of the present invention. The fact that methacrylic acid was polymerized was measured by IR (1 derived from C = C bond).
Absorption at 635 cm ^-1 disappeared and 285 derived from C-C bond
The absorption was increased from ⁰ to 2950 cm ^-1 ). The conductivity was 0.05 Scm ^-1 . Further, this conductivity did not change even when immersed in water or methanol.

Example 3 The same treatment as in Example 1 was carried out by using 3-chloroacrylic acid instead of acrylic acid. The weight gain per gram of film was 1.2 g, which indicates that 3-chloroacrylic acid was doped at a molar ratio of 1: 1 with respect to nitrogen atoms of polyaniline. The electric conductivity at this time was 0.04 Scm ⁻¹ . The doped polyaniline block was heated at 80 ° C. for 6 hours to obtain the polyaniline composite molded body of the present invention. The fact that 3-chloroacrylic acid was polymerized was measured by IR (1635 derived from C = C bond).
The absorption at cm ^-1 disappeared, and 2850 to 2 derived from C-C bond.
The absorption at 950 cm ⁻¹ was increased). The conductivity was 0.04 Scm ^-1 . Further, this conductivity did not change even when immersed in water or methanol.

Example 4 The same treatment as in Example 1 was carried out except that the immersion time in acrylic acid was changed to 30 minutes. Film 1g
The weight increase per unit was 0.4 g, which shows that acrylic acid was doped at a molar ratio of 1: 0.5 with respect to the nitrogen atom of polyaniline. The conductivity at this time is
It was 0.005 Scm ^-1 . The doped polyaniline film was heated at 80 ° C. for 6 hours to obtain the polyaniline composite molded body of the present invention. Acrylic acid was polymerized by IR measurement (absorption at 1635 cm ⁻¹ derived from C═C bond disappeared, and 2850 to 2950 cm ⁻¹ derived from C—C bond).
The absorption was increased). Conductivity is 0.0
It was 05 Scm ^-1 . Further, this conductivity did not change even when immersed in water or methanol.

Example 5 The same treatment as in Example 1 was carried out except that the time of immersion in acrylic acid was 12 hours. Film 1
The weight increase per gram was 1.2 g, which indicates that acrylic acid was doped at a molar ratio of 1: 1.5 with respect to the polyaniline nitrogen atom. The electrical conductivity at this time was 0.09 Scm ⁻¹ . The doped polyaniline film was heated at 80 ° C. for 6 hours to obtain the polyaniline composite molded body of the present invention. Acrylic acid was polymerized by IR measurement (absorption at 1635 cm ⁻¹ derived from C═C bond disappeared, and 2850 to 2950 cm derived from C—C bond).
^-1 increased absorption). The conductivity is 0.
It was 09 Scm ^-1 . Further, this conductivity did not change even when immersed in water or methanol.

Example 6 The same treatment as in Example 1 was carried out by using crotonic acid instead of acrylic acid. The weight gain per gram of film was 0.9 g, which indicates that crotonic acid was doped at a molar ratio of 1: 1 with respect to nitrogen atoms of polyaniline. The conductivity at this time is 0.02 Scm ^-1
Met. 8 of this doped polyaniline block
By heating at 0 ° C. for 6 hours, a polyaniline composite molded body of the present invention was obtained. The polymerization of 3-crotonic acid means that IR measurement (absorption at 1635 cm ⁻¹ derived from C═C bond disappears, and C
The absorption at 2850 to 2950 cm ⁻¹ derived from —C bond was increased). The conductivity was 0.02 Scm ^-1 . Further, this conductivity did not change even when immersed in water or methanol.

With respect to the composite molded article of the polyaniline and the carboxyl group-containing polymer of each of the above-mentioned examples, their characteristics were compared with those of the polyaniline before the compounding (before the polymerization of the α-ethylenically unsaturated carboxylic acid as the dopant). , Shown in Table 1.

[Table 1] From the results in Table 1 above, by polymerizing the α-ethylenically unsaturated carboxylic acid, which is a dopant, to form a composite, there is almost no decrease in strength in the doped state, and the conductivity does not decrease due to immersion in water. It can be seen that a composite molded body is obtained.

[0021]

As described above, in the polyaniline composite molded article of the present invention, the dopant α-ethylenically unsaturated carboxylic acid becomes a polymer and exists in a state of being entangled with the polyaniline main chain. Even in the state, the strength does not decrease, and it shows a stable doped state in which it is not dedoped by water or a polar solvent, and is very useful for various applications as an electronic material and a conductive material.

Claims (3)

[Claims] 1. The following general formula (I): (In the formula, m and n are integers of 0 or more, and m / (n
+ M) = 0 to 1, m + n = 10 to 5000. ) The number average molecular weight of the structural unit represented by
A polyaniline composite molded article, which comprises a polyaniline of 0000 and a carboxyl group-containing polymer formed from one or more of α-ethylenically unsaturated carboxylic acids. 2. The polyaniline according to claim 1, wherein the carboxyl group of the carboxyl group-containing polymer has a molar ratio of 1: 0.2 to 1: 1.5 with respect to the nitrogen atom of the polyaniline. Composite molded body. 3. A polyaniline molded product made of polyaniline having a number average molecular weight of 2000 to 500000, which comprises the structural unit represented by the general formula (I), is impregnated with one or more kinds of α-ethylenically unsaturated carboxylic acid. After letting
The method for producing a polyaniline composite molded article according to claim 1, wherein the α-ethylenically unsaturated carboxylic acid is polymerized in the polyaniline molded article.