JPH0635510B2 - Method for producing polyaniline having rod-shaped morphology - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing polyaniline useful as a capacitor material, a battery electrode material, and the like, and more specifically, a polyaniline having a rod-shaped morphology by a chemical polymerization method. Manufacturing method.

[Conventional technology]

A method for chemically or electrochemically oxidatively polymerizing aniline or a derivative thereof in an acidic solvent by the action of an oxidizing agent is known [for example, A. F. Diaz et al., Journal of Electroanalytical Chemistry, 111, 111 (1980) (AFDiaz et al,
J. Electroanal. Chem., 111 , 111 (1980))].

Further, it has been proposed to use the polyanilines thus obtained as an electrode for an aqueous solution type or non-aqueous solvent type battery [eg, A.G. McDaeamide, Polymer Preprints, Vol. 25, No. 2 and No. 2
48 pages (1984) (AGMacDiarmid et al, Polymer.Prep
rints, 25 (2), 248 (1984))].

[Problems to be solved by the invention]

However, although the conventionally known chemical polymerization method is useful as a method for obtaining polyanilines in good yield,
Polymerization is carried out in an acidic aqueous solvent in which the polyanilines to be formed are sparingly soluble or insoluble, and as the polymerization progresses, polyanilines are deposited as fine powders that are extremely difficult to overseparate. There is.

Further, the thus obtained fine particle polyaniline has extremely poor moldability and has a defect that the molded product is extremely fragile even by compression molding.

On the other hand, in the method of electrochemically oxidatively polymerizing aniline or a derivative thereof, the polymerization reaction proceeds from the electrode surface to form thin film-shaped (having a rod-shaped morphology) polyanilines, and the obtained polyanilines are oxidized. ~ Proposals have also been made for applying it to a display device as an electrochromic material by utilizing reversible color change in a reduced state [eg Yoneyama et al., Journal of Electroanalytical Chemistry, Vol. 161, 419].
Page (1980) (H.Yoneyama et al., J. Electroanal.Che
m., 161 , 419 (1980))].

Although this method is suitable as a polymerization method corresponding to a specific application, which takes advantage of the function as a thin film as described above,
It is extremely low in productivity and must be said to be unsuitable for obtaining a large amount of polyanilines.

Therefore, an object of the present invention is to provide a method for producing a polyaniline having a rod-shaped morphology by a chemical polymerization method.

[Means for Solving Problems and Their Actions]

In view of the above-mentioned drawbacks of the prior art, the present inventors have conducted various studies to obtain polyanilines having a morphology similar to that of the electrochemical polymerization method by a chemical polymerization method, and as a result, aniline, p-aminodiphenylamine or those When chemically polymerizing a derivative of, by coexisting with thionine acetate, the above-mentioned object can be effectively achieved, and polyaniline having a morphology similar to that of the polyaniline obtained by the electrochemical polymerization method can be obtained. Heading out, the present invention has been completed.

That is, according to the present invention, when aniline, p-aminodiphenylamine or a derivative thereof is chemically oxidatively polymerized in an acidic solvent by the action of an oxidizing agent to produce polyaniline, a coexistence of a thionine acetate salt can be achieved. It has a characteristic rod-like morphology. A method for producing polyanilines is provided.

The aniline, p-aminodiphenylamine or their derivatives used in the present invention are represented by the following general formula (I)
It is represented by (II).

(However, in the formula, R ^{1 to} R ⁵ represent hydrogen, which may be the same or different, an alkyl group having 1 to 5 carbon atoms, an alkoxyl group, or an aryl group, and m, p, and q are 0 to 2 As typical examples of the compounds represented by the general formulas (I) to (II), aniline, N-methylaniline, diphenylamine, o-toluidine, m-toluidine, 2,5-dimethylaniline, N-methyldiphenylamine, Examples thereof include N, N'-diphenyl-p-phenylenediamine. These aniline, p-aminodiphenylamine or their derivatives can be used alone or as a mixture of two or more kinds, and the amount thereof used is 10 ⁻³ to 4 mol / concentration in an acidic solvent, preferably It is 10 ^{-2 to} 2 mol / mol.

Thionine acetate used in the present invention is aniline, p-
It is used in the range of 10 ^-4 to 1 mol, preferably 10 ^{-3 to} 0.5 mol, per 1 mol of aminodiphenylamine or a derivative thereof. It is not clear why the addition of thionine acetate significantly changes the morphology of polyanilines, and it is considered that thionine acetate is copolymerized with aniline, p-aminodiphenylamine or their derivatives as an aromatic diamine component. Since the object of the present invention cannot be achieved even if a homologous thionine hydrochloride is used, the effect of adding thionine acetate is extremely specific.

The oxidizing agent used in the present invention is not particularly limited, but typical examples are ammonium persulfate, potassium persulfate, potassium dichromate, potassium permanganate or iron salts in the form of a redox-based combination of hydrogen peroxide. And the like, and ammonium persulfate is preferable. The amount of the oxidizing agent used is aniline, p-aminodiphenylamine or their derivatives 1
The amount is 0.1 to 3 mol, preferably 0.5 to 2 mol per mol.

As the acidic solvent, an aqueous solution of sulfuric acid, hydrochloric acid, hydrofluoric acid, hydrofluoric acid, hydrobromic acid, hexafluorophosphoric acid, benzenesulfonic acid, p-toluenesulfonic acid, or the like is used. In addition, when aniline, p-aminodipheninamine or their derivatives are difficult to dissolve, an organic solvent which is inert to the oxidizing agent and miscible with water may be used in combination.

The concentration of the acid in the acidic solvent is 0.1 mol to 1 mol of aniline, p-aminodiphenylamine or their derivatives.
It is 10 mol, preferably 0.5 mol to 5 mol.

The polymerization temperature varies depending on the decomposition temperature of the oxidizing agent used, but is usually in the range of 0 to 100 ° C, preferably 10 to 80 ° C. The polymerization time cannot be unconditionally specified because it depends on the type and amount of the oxidizing agent, the polymerization temperature, etc., but it is usually 0.5 to 24 hours, preferably 1 to 12 hours.

〔The invention's effect〕

The conductivity of the polyaniline having a rod-shaped morphology obtained by the method of the present invention is 10 ⁻³ to 10 S / at room temperature.
cm, and has almost the same performance as polyanilines obtained by a usual electrochemical polymerization method.

Further, the polyaniline having a rod-like morphology obtained in the present invention is easily overseparated, has excellent moldability, and has good mechanical strength of the molded product. Further, the polyanilines of the present invention are extremely interesting polymers whose morphology and the above characteristics do not change even when chemically compensated with a base such as ammonia or triethylamine. Therefore, the polyaniline having a rod-like morphology according to the present invention is extremely useful as a battery electrode material or a capacitor material.

〔Example〕

 Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 500 ml of distilled water was added to a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, and 500 ml of distilled water was bubbled through the flask.
To this, 2 g (7 mmol) of thionine acetate was added, heated, and stirred and dissolved at 40 ° C. After the thionine acetate was completely dissolved, 25.92 g (0.2 mol) of aniline hydrochloride was added and dissolved. Next, ammonium persulfate 45.6 g (0.
2 mol) was added slowly as a solid. When the internal temperature reached 45 ° C, the outside was ice-cooled to keep the internal temperature at 38 to 40 ° C, and the reaction was carried out for 1.5 hours. During this time, the solution became extremely viscous and a black-green precipitate was deposited. After completion of the reaction, suction was carried out, and the residue was washed 3 times with 500 ml of 1N-hydrochloric acid. The solid was air dried overnight and then dried at 80 ° C. under vacuum overnight to obtain 20.7 g of dark green polyaniline. The scanning electron microscope (SEM) photograph of the obtained polyaniline is as shown in FIG. 1, and it was a rod-shaped polymer having a diameter of about 2 μm and a length of about 20 μm. The shape of this polyaniline is
For example, it did not change even after compensation treatment with an inorganic base such as ammonia water, and the shape was retained even when it was re-oxidized with an oxidizing agent such as hydrochloric acid or bromine. Furthermore, the specific surface area was measured by the BET method and found to be 38 m ² / g, which was about the same as the specific surface area of polyaniline obtained by the electrochemical polymerization temperature of aniline. Further, the polyaniline obtained in this example was subjected to compression molding at a pressure of 300 kg / cm ² using a tablet molding machine for IR spectrum measurement, and the dark blue pellets obtained were subjected to the two-terminal method to measure the conductivity at room temperature. When measured, it was 2.4 × 10 ⁻³ S / cm. The IR spectrum of this polyaniline is shown in FIG.

Comparative Example 1 The reaction of Example 1 was repeated except that thionine acetate was not used, to obtain 22.6 g of polyaniline. The conductivity (two-terminal method) of this polyaniline at room temperature is 5.2 × 10 ^-3 S / c
It was m. In addition, the third SEM picture of this polyaniline
As shown in the figure. As a result of observing SEM photographs, this polyaniline did not have rod-shaped morphology.

Comparative Example 2 The reaction of Example 1 was repeated except that 1.84 g (7 mmol) of thionine hydrochloride was used instead of thionine acetate. The yield of polyaniline was 19.7 g. The electrical conductivity (two-terminal method) of this polyaniline at room temperature is 3.6 × 10 ^-3 S / cm
However, the SEM observation result showed that polyaniline which was powdery and had rod-like morphology could not be obtained.

Comparative Example 3 The reaction of Example 1 was repeated except that 2 g of diaminodiphenylmethane was used instead of thionine acetate, and 2.4 × 1.
Although 18.7 g of polyaniline having a room temperature conductivity (two-terminal method) of 0 ^-3 S / cm was obtained, the SEM observation result showed that the polyaniline did not have a rod-shaped morphology.

Examples 2 to 7 According to Example 1, various anilines or their derivatives were used to carry out oxidative polymerization in the presence of thionine acetate under various conditions. The results are shown in Table 1.

From the comparison with each of the above Examples and Comparative Examples, the specific effect of addition of thionine acetate during the polymerization of polyanilines is clear.

[Brief description of drawings]

FIG. 1 and FIG. 2 show scanning electron micrographs (5000 times) of the polyaniline obtained in Example 1 and its IR spectrum. FIG. 3 shows a scanning electron micrograph (5000 times) of polyaniline in the case where thionine acetate was not used.

Claims (1)

[Claims] 1. A method for producing polyaniline by chemically oxidizing and polymerizing aniline, p-aminodiphenylamine or a derivative thereof in an acidic solvent by the action of an oxidizing agent, wherein a thionine acetate salt is allowed to coexist. A method for producing a polyaniline having a rod-like morphology.