JPH0826112B2 - Novel copolymers and electroactive polymers derived therefrom - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel polymer, and more particularly to a novel conductive polymer and its precursor.

[Problems to be Solved by Prior Art and Invention]

As a polymer used for forming a conductive polymer, polyacetylene, polyparaphenylene, polythiophene, polypyrrole and the like are known. These polymers can be used as a conductive polymer by doping a certain compound, but they have the drawback that they are easily denatured in the air and their electrical characteristics change. Further, these conductive polymers have problems such as extremely poor processability due to poor melting and solubility properties, which is a major obstacle to practical use. For example, as an application field of conductive polymers, application to secondary battery electrodes utilizing the reversible redox properties of conductive polymers has been proposed. It is physically or chemically unstable, and is therefore the basic performance required for secondary batteries. Stable charge / discharge repetitive characteristics (cyclability).
Can not be expected. Further, since the polymer skeleton of the conductive polymer is made of a rigid π-electron conjugated system, it is insoluble and infusible, which is a major obstacle to practical use. As a method for solving these problems, JP-A-61-206170 discloses an electroactive polymer obtained by doping a polymer having a 4,4'-diphenylamine structure as a repeating unit with an electron acceptor or an electron donor. Has been proposed as an electrode material for secondary batteries.

However, the above-mentioned diphenylamine-based polymer is an oligomer having a low degree of polymerization and does not have the mechanical strength and moldability that should be originally provided as a polymer compound. For example, when this polymer is used as an electrode material for a secondary battery, However, there is a problem that the soluble component elutes with repeated charge and discharge, so that cyclovirity cannot be expected. Further, in order to give the above-mentioned diphenylamine-based polymer good mechanical properties and moldability at the same time as good electrochemical properties, it is necessary to obtain a polymer having a higher degree of polymerization (high polymer). It is difficult to obtain a high molecular weight polymer even by Grignard coupling, oxidative coupling, Friedel-Crafts reaction and electrolytic oxidative polymerization, which are generally used as a synthetic method of an aromatic compound or a polyheteroaromatic compound. In addition, even if the reaction conditions are made more severe, it is not possible to expect a high molecular weight by inducing a heterogeneous bond or a cross-linking reaction. There was a problem that it became a chemically inactive polymer.

In order to solve these drawbacks of the prior art, the present inventors have already dissolved in a solvent such as N-methylpyrrolidone, nitrobenzene, sulfuric acid, etc., and since they are thermoplastic resins, they are excellent in moldability and processability. By doping with an electron-accepting compound, the electrical activity is improved, and the redox reaction can be performed with good repeatability, so the following general formula expected to be applied to various electronic devices and batteries etc. The inventors have found a copolymer represented by and have already filed a patent application (Japanese Patent Application No. 62-143267).

However, when the above copolymer is applied to a battery electrode, there is a problem in that the charge / discharge capacity per weight of the electrode active substance becomes small, and improvement has been desired.

[Means for Solving the Problems] As a result of further intensive studies to improve these drawbacks, the present inventors have found that by using the copolymer represented by the following general formula (I), the drawbacks of the prior art are The present invention has been found to be solved and has reached the present invention.

That is, the invention has the general formula (I) (In the formula, R ¹ is H or a hydrocarbon residue having 1 to 20 carbon atoms, R ²
Is H, a hydrocarbon residue having 1 to 20 carbon atoms, a furyl group, a pyridyl group, a nitrophenyl group, a chlorophenyl group or a methoxyphenyl group, 1 is an integer of 2 or more, m is an integer of 1 or more, and n is 2 And each of the above integers is shown).

The present invention also relates to an electroactive polymer obtained by doping the copolymer represented by the general formula (I) with an electron acceptor.

 Hereinafter, the present invention will be described in detail.

The copolymer represented by the general formula (I) of the present invention is produced by polycondensing a compound represented by the general formula (III) and an aldehyde represented by the general formula (IV) or a polymer thereof. be able to.

R ² CHO (IV) In the compound represented by the general formula (III), R ¹ represents hydrogen or a hydrocarbon residue having 1 to 20 carbon atoms, preferably 1 to 8 carbon atoms, and the hydrocarbon residue is a methyl group. , Ethyl group, n-propyl group, i-propyl group, n-butyl group,
Examples thereof include alkyl groups such as i-butyl group and n-hexyl group or allyl groups, various aryl groups such as phenyl group, tolyl group, ethylphenyl group, aralkyl groups and derivatives thereof. 1 is 2 or more, usually 2 to 50, preferably 2 to 10, more preferably 2 to 5. m is 1 or more, and is usually 1 to 50, preferably 1 to 30, and more preferably 1 to 10. Although both ends of the formula are not particularly specified, they are usually nuclear-substituted hydrogen.

Specifically as the compound represented by the general formula (III),
Examples thereof include N, N'-diphenyl-p-phenylenediamine compounds and N-phenyl-N '-(4-phenylamine) phenyl-p-phenylenediamine compounds.

Further, among the compounds represented by the general formula (III), m
Is 2 or more, m is usually represented by the general formula (III).
In the case of = 1, the compound is produced by using a method such as an oxidative coupling reaction using an oxidizing agent such as a manganese compound or a ferric salt, or an electrolytic oxidative polymerization. For example, the compound represented by the general formula (III) is N, N'-diphenyl-p.
-In the case of a phenylenediamine compound, N, N'-diphenyl-p-phenylenediamine is produced by an oxidative coupling reaction using ferric chloride as a catalyst in a solvent such as ethanol, acetone, acetonitrile, ether or benzene. can do.

The reaction temperature at this time is -50 ° C to 100 ° C, preferably -20 ° C to the boiling point of the solvent used, and the reaction time is 10 minutes to 10 ° C.
The reaction can be carried out for 0 hours, preferably 1 hour to 50 hours.

Incidentally, among these N, N'-diphenyl-p-phenylenediamine, typical ones are N, N'-dimethyl-N, N'-diphenyl-p-phenylenediamine, N,
N'-diethyl-N, N'-diphenyl-p-phenylenediamine, N, N'-dipropyl-N, N'-diphenyl-p-
Examples thereof include phenylenediamine.

In addition, compounds represented by the general formula (III) other than N, N'-diphenyl-p-phenylenediamine compounds are also produced by a conventional method, for example, aromatic amines in the presence of a transition metal catalyst. And an aromatic hydroxy compound in an organic solvent, a method of using as a phthalic acid ester raw material, and the like. Specific examples of these include JP-A-55-38311, Journal of polymer Scie
nce Part C 22, p.451 (1968).

As the aldehyde represented by the general formula (IV),
R ² is hydrogen or a hydrocarbon residue having 1 to 20 carbon atoms, preferably 1 to 8 carbon atoms, or a compound having a furyl group, a pyridyl group, a nitrophenyl group, a chlorophenyl group or a methoxyphenyl group is used. Is a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group,
An alkyl group such as i-butyl group and n-hexyl group or an allyl group, various aryl groups such as phenyl group, tolyl group and ethylphenyl group, aralkyl group and derivatives thereof can be used. Typical of these aldehydes are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde,
Examples thereof include benzaldehyde, acrylaldehyde, cinnamaldehyde, anisaldehyde, nicotinaldehyde, nitrobenzaldehyde, chlorobenzaldehyde and furfural.

In addition, the polymer of aldehyde, the aldehyde represented by the general formula (IV) in a concentrated solution to self-condensation,
Represents a polymer obtained by condensation in the presence of an acid catalyst,
The polymer represents a polymer which is easily hydrolyzed to form an aldehyde monomer under the reaction conditions for synthesizing the copolymer of the present invention. Typical examples include paraformaldehyde, which is a polymer of formaldehyde, and paraaldehyde, which is a trimer of acetaldehyde.

The polycondensation of the compound represented by the general formula (III) and the aldehyde can be carried out in an organic solvent in which both are soluble at a temperature of 0 ° C to 200 ° C using an acid or alkali catalyst. Examples of the acid catalyst include inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, perchloric acid and diphosphorus pentoxide, and organic acids such as formic acid, acetic acid, propionic acid, methanesulfonic acid and p-toluenesulfonic acid. it can. These acid catalysts may be used alone or in combination of two or more kinds. Examples of preferable organic solvents include ethers such as ethyl ether, tetrahydrofuran and dioxane, halogenated hydrocarbons such as chloroform, dichloromethane and chlorobenzene, nitro compounds such as nitrobenzene, acetonitrile, propylene carbonate, dimethylformamide and N-methyl. Examples include pyrrolidone. Reaction time is 1 minute to 500
The time can be appropriately selected within the range of preferably 5 minutes to 200 hours.

The thus-obtained copolymer represented by the general formula (I) has n of 2 or more, usually 2 to 1000, preferably 5 to 200, and has a substantially linear structure.

The copolymer of the present invention is soluble in solvents such as N-methylpyrrolidone, nitrobenzene, chloroform and sulfuric acid, but insoluble in alcohol, aliphatic hydrocarbons, acetonitrile and propylene carbonate used in organic electrolyte type batteries. Further, it is a thermoplastic resin that can be melted by heating and is excellent in processability, so that various molded articles of any shape can be formed.

The copolymer of the present invention, by doping with an electron acceptor as a dopant, shows high electric activity, and of course, it is possible to repeat the redox reaction with good repeatability,
Since it has high conductivity, it can be used for various electronic devices. For example, when used as an electrode material for secondary batteries, reversible charge / discharge is possible,
Particularly, even if the number of charge / discharge cycles (cycle number) is remarkably increased, it is possible to obtain extremely stable characteristics without causing the elution phenomenon and the decrease in cyclability as seen in the case of diphenylamine polymers. it can.

Further, the copolymer of the present invention is capable of thinning into a large area and is excellent in workability, and by doping, it is possible to impart stable conductivity from an insulator to a semiconductor and a semimetal level, thereby utilizing a solar cell, a transistor, It can be used as various bonding elements such as diodes, electromagnetic interference preventing materials, and antistatic materials.

Electron-accepting dopants include halogen compounds such as iodine, bromine, hydrogen iodide, arsenic pentafluoride, phosphorus pentachloride, phosphorus pentafluoride, antimony pentafluoride, silicon tetrafluoride, aluminum chloride, aluminum bromide. , Aluminum fluoride, metal halides such as ferric chloride, sulfuric acid, nitric acid, protic acids such as chlorosulfonic acid, sulfur trioxide, oxidizing agents such as difluorosulfonyl peroxide, tetracyanoquinodimethane, etc. There can be mentioned various organic substances. The electrochemical doping can _{^{dopant, PF 6 -, SbF 6 -}} , AsF 6 - , such as Va
Halide anions of a metal selected, BF ₄ ^- IIIa metal selected halide anions, such _{^{as, I - (I 5 -)}} , Br -, Cl -
Halogen anion such as, ClO ₄ ^- include anions such as perchlorate anion such as.

These dopings are performed by a known method.
As a typical example, when the electron-accepting dopant is a gas or has a high vapor pressure, the vapor phase doping method of exposing the copolymer of the present invention to the vapor atmosphere, the electron-accepting dopant being inactive In a solution dissolved in a solvent,
Wet doping method of immersing, in a solution of an electron-accepting compound dissolved in an inert solvent, the copolymer of the present invention is dissolved, and a dry film is formed from the solution to form a film or a coating film. Examples thereof include a method of simultaneous doping, and a method of electrochemically doping by applying an electric field after immersing in a solution containing a dopant.

Further, the copolymer of the present invention has the property that when anion is doped, the nitrogen atom in the copolymer is positively charged and is in a stable state, so that it is stable against repeated redox and high. Utilizing the characteristics of having conductivity and having excellent workability as described above, various functional electrodes such as batteries, various bonding elements such as solar cells, transistors and diodes, electromagnetic interference preventing materials, charging Used as a preventive material.

That is, the copolymer represented by the general formula (I) of the present invention is dissolved in a solvent and the compounded compound is added, followed by molding.
Forming the polymer composition of the present invention by heating and melting, or press-molding the polymer composition as a main component, or forming into an arbitrary shape using a binder to form an electrode. You can Examples of the binder include, but are not limited to, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl chloride, and polyethylene.

At this time, an additive such as carbon black may be added as long as it does not adversely affect the copolymer of the present invention.

〔The invention's effect〕

Since the copolymer of the present invention is linear, it has excellent processability, and various molded products can be easily manufactured. Also,
By doping the copolymer of the present invention with an electron acceptor, high conductivity can be exhibited, and the doping is reversible and has extremely high cyclability. As excellent.

〔Example〕

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

Example 1. 1.00 g of N, N'-dimethyl-N, N'-diphenyl-p-phenylenediamine in a 100 ml three-necked flask purged with nitrogen.
Then, 15 ml of nitrobenzene and 6 ml of acetic acid were added and dissolved, 120 μl of sulfuric acid and 250 μl of propionaldehyde were added, and the mixture was reacted at 50 ° C. for 140 hours while stirring. The reaction solution was poured into 300 ml of ethanol containing 30 ml of NaOH, the reddish brown precipitate was filtered, washed with ethanol and distilled water, and then dried to obtain 0.85 g of an off-white powder. ¹ H-NM of the obtained powder
The R, ¹³ C-NMR and IR (Fig. 1) were measured and found to have the following structure.

¹ H-NMR (C ₆ D ₆ ): (ppm) 6.82 to 7.20 (m), 3.65
(M), 2.97 (m), 2.02 (m), 0.92 (t). ¹³ C-NMR (CDCl ₃ ): (ppm) 147.4, 143.7, 137.4, 12
8.4, 122.6, 118.6, 51.8, 40.4, 28.9, 12.9.

Reference Example The copolymer obtained in the example was dissolved in chloroform to prepare a chloroform solution of the copolymer. After immersing a platinum wire in the solution, a copolymer thin film was attached on the dried platinum wire to prepare a measurement electrode.

Cyclic voltammetry of the above electrodes was measured in a dry nitrogen atmosphere using a 1 M solution of Et ₄ NPF ₆ in acetonitrile as an electrolyte, a platinum plate as a counter electrode, and an Ag / AgCl electrode as a reference electrode. The sweep speed was 50 mV / sec. The obtained results are shown in FIG. It showed reversible and extremely stable redox behavior with no change even after several tens of redox cycles.

Example 2. In a 100 ml three-necked flask with nitrogen substitution. Add 1.00 g and add 20 ml of nitrobenzene to dissolve, then p-toluenesulfonic acid 100 μl, paraaldehyde
1.2 ml was added and reacted at 80 ° C. for 3 hours while stirring.
The reaction solution was poured into 300 ml of ethanol containing 30 ml of NaOH, filtered with an off-white precipitate, washed with ethanol and distilled water, and then dried to obtain 0.73 g of an off-white powder.

Reference Example 2. The cyclic voltammetry of the copolymer obtained in Example 2 was measured in the same manner as in Reference Example 1. As a result, there was no change even after several tens of redox cycles, and the reversible and extremely stable oxidation was observed. It showed a reduction behavior.

Example 3. In a 100 ml three-necked flask with nitrogen substitution. After adding 1.00 g and adding 20 ml of nitrobenzene to dissolve it, 110 μl of a mixture of diphosphorus pentoxide and methanesulfonic acid in a ratio of 1:10 by weight and 110 ml of paraaldehyde were added and reacted at 80 ° C. for 3 hours with stirring. It was The reaction solution was poured into 300 ml of ethanol containing 30 ml of NaOH, filtered over a gray precipitate, washed with ethanol and distilled water, and then dried to obtain 0.80 g of an off-white powder.

Reference Example 3. The cyclic voltammetry of the copolymer obtained in Example 3 was measured in the same manner as in Reference Example 1. As a result, there was no change even after several tens of redox cycles, and the reversible and extremely stable oxidation was observed. It showed a reduction behavior.

[Brief description of drawings]

FIG. 1 is an infrared absorption spectrum diagram of the copolymer obtained in Example 1, and FIG. 2 shows the measurement results of the cyclic voltammetry of the electrode in Reference Example 1.

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Claims (2)

[Claims] 1. A general formula (I) (In the formula, R ¹ is H or a hydrocarbon residue having 1 to 20 carbon atoms, R ²
Is H, a hydrocarbon residue having 1 to 20 carbon atoms, a furyl group, a pyridyl group, a nitrophenyl group, a chlorophenyl group or a methoxyphenyl group, 1 is an integer of 2 or more, m is an integer of 1 or more, and n is 2 A copolymer represented by the above integers). 2. An electroactive polymer obtained by doping a copolymer represented by the general formula (I) with an electron acceptor.