JPS6119631A - Electroconductive material and its production - Google Patents

Abstract

PURPOSE:To obtain an electroconductive organic polymer which is stable and excellent in moldability, by baking a high-MW aniline oxidation polymer at a specified temperature in an inert atmosphere or in vacuum. CONSTITUTION:A high-MW aniline oxidation polymer is baked at a temperature >=700 deg.C in an inert atmosphere or in vacuum to produce an electroconductive material of an electric conductivity >=10<-1>S/cm. It is preferable that the high- MW aniline oxidation polymer has an electric conductivity >=10<-10>S/cm, particularly, >=10<-6>S/cm. Further, said high-MW aniline oxidation polymer may have such a high MW that it is insoluble in conc. sulfuric acid, but on the other hand, when it is soluble in conc. sulfuric acid, it is preferable that the polymer has a logarithmic viscosity >=0.1 when measured in a 0.5g/l solution in conc. sulfuric acid at 30 deg.C. Said electroconductive high-MW aniline oxidation polymer can be obtained by oxidatively polymerizing aniline in the presence of, preferably, a chemical oxidizing agent or polymerizing aniline by electrolytic oxidation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conductive material and a method for producing the same, and more particularly to a highly conductive material obtained by firing an oxidized aniline polymer and a method for producing the same.

Most organic materials are electrically insulating, however, a group of organic polymers with electrical conductivity known as organic semiconductors have received attention in recent years. Organic materials that are themselves electrically conductive are generally classified into three types. The first is graphite. Although graphite is not strictly considered an organic material, it can be considered to have the ultimate structure of an organic conjugated system. Graphite itself already has fairly high conductivity, but by intercalating it with various compounds, it can be made to have even higher conductivity, eventually becoming a superconductor. However, graphite has strong two-dimensionality and is difficult to mold.
This poses an obstacle in its application.

The second type is a charge transfer complex, and for example, a crystalline substance obtained using tetrathiafulvalene and tetracyanoquinodimethane as an electron donor and an electron acceptor, respectively, has a very high conductivity of 400 to 5003/cn at room temperature. However, since such charge transfer complexes are not polymers, they have the same difficulty in moldability as graphite for practical application.Secondly, as typified by polyacetylene, doping It is a π-electron conjugated organic polymer that has high electrical conductivity. The conductivity of polyacetylene before doping is 1O-5S/cm for the trans type and 1 for the cis type.
0-1 S/cm, and has properties close to those of a semiconductor or an insulator. However, by doping such polyacetylene with an electron-accepting compound such as arsenic pentafluoride, iodine, sulfur trioxide, ferric chloride, etc. or an electron-donating compound such as an alkali metal, p
It is possible to form a type semiconductor and an n-type semiconductor, and it is also possible to provide high conductivity as high as 10"S/cm. Although polyacetylene is a theoretically interesting conductive organic polymer, On the other hand, polyacetylene is extremely susceptible to oxidation, and its properties change significantly due to oxidative deterioration in the air.In a doped state, it is sensitive to layer oxidation, and even a small amount of moisture in the air causes it to become conductive. This tendency is particularly remarkable for n-type semiconductors.

Furthermore, poly(p-phenylene) and poly(p-phenylene sulfide) have electrical conductivities of 1O-9S/am and 10-''S/cm, respectively, before doping, but when doped with arsenic pentafluoride, for example, By doing so, the conductivity is 500S/cm and IS/cm, respectively.
It can be a conductive organic polymer. The electrical properties of these doped organic polymers are also unstable to varying degrees.

It is a common phenomenon among these types of conductive organic polymers that the electrical properties of conventional conductive organic polymers doped in this way are generally very unstable to the environment. This poses an obstacle to practical application. Also,
The organic conductive substances described above generally have poor moldability, which also hinders their practical application.

For this reason, on the other hand, in addition to aromatic polymers such as polyphenylene, polyphenyl ether, and polyimide, vinyl polymers such as polyacrylonitrile and polyvinyl alcohol, and aromatic low molecular weight polymers such as coal tar pitch and tetrabenzophenazine, etc. Obtaining conductive materials by firing materials has also been practiced for a long time. However, since the above-mentioned polymers and low-molecular-weight materials undergo a phase change during the firing process, it is difficult to obtain a molded product by firing after molding them into a predetermined shape, or the polymers and low-molecular-weight materials are In order to suppress decomposition during the firing stage, it is usually necessary to perform preliminary firing in air, making the manufacturing process cumbersome.

However, in recent years, conductive organic polymers can be obtained as films by electrolytically oxidizing heterocyclic compounds such as pyrrole and thiophene (K, Kana et al.
zawa et al-+ SynthlMet, 1
+ 329 (1980); Tourillon, G.
et al, +, r, Electroanal.

CheIll., 135.173 (1982))
In particular, such polymers are reported to be stable even in air because they are doped during the electrolytic oxidation step.

Oxidized polymers of aniline, for example oxidized polymers of aniline as oxidized dyes 2, have also been known for a long time in connection with aniline black. In particular, aniline 8 of formula (I) is used as an intermediate for the production of aniline black.
The substance has been confirmed as emeraldine (^, G.

Green et al., J. Chem. So.
c, +97.2388 (1910); Dan 1, 111
7 (1912)), which is soluble in 80% acetic acid, cold pyridine and N,N-dimethylceramamide. In addition, this emeraldine is oxidized in an ammoniacal medium to produce nigraniline (nigraniline) represented by formula (n).
iline), which is also known to have similar solubility properties to emeraldine.

Furthermore, in recent years, it has been discovered by R. Buvet et al. that this sulfate of emeraldine has high conductivity (J, Polymer Sci, +
C, 16+2931; 2943 (1967);
η, 1187 (1969)).

It is also already known that an organic substance similar to emeraldine can be obtained by electrolytic oxidation of aniline (
D., M., Mobilner et al., J.
8mer.

Chem, Soc, +84.3618 (19'6
2) ), that is, according to this, an aqueous sulfuric acid solution of aniline is oxidized by +〇, 8■ with respect to a standard calomel electrode (hereinafter referred to as SCE) in order to avoid electrolysis of water using a platinum electrode. Electrolytic oxidative polymerization at potential yields a material that is 80% soluble in acetic acid, pyridine and N,N-dimethylformamide.

Others % Diaz et al. (J, Electroanal
, Chem, +ill+ (1980)), Koyama et al. (Proceedings of the Society of Polymer Science and Technology, in Japanese, (7).

1524 (1981)) also attempted electrolytic polymerization of aniline, but both aimed at polymer-coated chemically modified electrodes, and the electrolysis was performed at a potential of 1 or less with respect to SCE.

The present inventors have conducted intensive research on the oxidative polymerization of aniline in order to obtain highly conductive materials that are stable and have excellent moldability, especially conductive organic polymers. By oxidative polymerization of the aniline water-soluble salt with a chemical oxidizing agent in a protic acid-containing reaction medium,
In particular, the protonic acid/potassium dichromate molar ratio is 1.2.
By doing so, it has a higher molecular weight than the above-mentioned emeraldine, and is stable without requiring a new doping operation because it has already been doped with the protonic acid used in the oxidative polymerization step. Highly conductive aniline oxidized polymers can be obtained which are insoluble in water and most organic solvents and have a conductivity of typically 10.
``We found that it is more than 1S/cm (patent application 1973-
z1228o).

In addition, the above chemical oxidation and polymerization can also be carried out by electrolytically oxidizing and polymerizing aniline at a predetermined current density at an electrolytic potential higher than +1■ with respect to a standard calomel electrode with an aniline solution containing an equivalent amount or more of protonic acid to aniline. We have found that it is possible to obtain a highly conductive aniline oxidized polymer having a high molecular weight and doped with the supporting electrolyte used (Japanese Patent Application No. 58-212).
No. 281).

The present inventors have discovered that the above-mentioned aniline oxidized polymer
After that, as a result of further intensive research, it was discovered that by firing the aniline oxidized polymer containing the above polymer, it was possible to obtain a material with even higher conductivity and, if necessary, as a molded product. The present invention was achieved by discovering that this can be done.

The electrically conductive material according to the present invention is composed of a fired product of a high molecular weight aniline oxidized polymer, and is characterized by having an electrical conductivity of 10-1 S/0 m or more; It is obtained by calcining the polymer at a temperature of 700° C. or higher in an inert atmosphere or under vacuum.

The high molecular weight aniline oxidized polymer used in the present invention has an electrical conductivity of 10-''S/crn or higher, particularly 1O-6S/crn.
The molecular weight of such a high molecular weight aniline oxidized polymer may be so high that it does not dissolve in concentrated sulfuric acid. Logarithmic viscosity of 0.5g/di solution is 30
It is preferably 0.1 or more at °C.

Such conductive high molecular weight oxidized aniline polymers can be prepared by oxidative polymerization of aniline with a chemical oxidizing agent or by electrolytic oxidative polymerization of aniline under predetermined conditions, preferably according to the present invention, as described above. Obtainable.

According to the present invention, to obtain conductive oxidized aniline polymers by oxidation of aniline with a chemical oxidizing agent, a water-soluble salt of aniline is oxidatively polymerized in an aqueous oxidizing agent solution containing a protic acid and an oxidizing agent.

As the aniline water-soluble salt, mineral acid salts such as hydrochloric acid and sulfuric acid are usually suitable, but are not limited to these.

Further, the oxidizing agent is not particularly limited, but chromium (IV) oxide and dichromates such as potassium dichromate and sodium dichromate are suitable, and potassium dichromate is particularly optimal. be. However, chromium-based oxidizing agents such as chromic acid, chromate, and chromyl acetate, and manganese-based oxidizing agents such as potassium permanganate can also be used as necessary. In addition, as protonic acids, sulfuric acid, hydrochloric acid, hydrobromic acid, tetrafluoroboric acid (1IBF4)
, hexafluorophosphoric acid (HPFb), etc. are used, and hydrochloric acid or sulfuric acid is particularly preferred.

When using mineral acids to form aniline water-soluble salts,
This mineral acid may be the same as or different from the protic acid described above.

The conductive aniline oxide polymer used in the present invention is preferably used when oxidatively polymerizing a water-soluble aniline salt with an oxidizing agent in an aqueous protonic acid solution. The ratio is 1.
2 or more, preferably 2 or more.

The reaction temperature is not particularly limited as long as it is room temperature or below the boiling point of the solvent used, but the higher the reaction temperature, the lower the conductivity of the resulting aniline oxidized polymer tends to be. From the viewpoint of obtaining the desired temperature, the temperature is preferably from low temperature to around room temperature.

In the above method, the reaction is preferably carried out by adding the protonic acidic oxidizing agent aqueous solution dropwise or all at once into the aqueous solution of the aniline water-soluble salt while stirring. Usually, the polymer precipitates immediately after an induction period of several minutes. The reaction is like this.

The process ends immediately, but is usually followed by stirring for several minutes to several hours for ripening. Next, the reaction mixture is poured into a large amount of water or an organic solvent, the polymer is filtered out, washed with an organic solvent such as acetone until it is no longer colored, and dried in vacuum to obtain a conductive polymer with aniline oxide. You can get a combination. □ In the above method, the conductivity of the conductive high molecular weight aniline oxidized polymer obtained is closely related to the reaction system in which the oxidative polymerization of aniline is carried out, that is, the composition of the aqueous solution containing the oxidizing agent, and it is highly conductive. In order to obtain a highly conductive aniline oxidized polymer, it is necessary to optimally select the composition of the aqueous solution. As mentioned above, it is necessary to carry out the reaction so that the molar ratio of protonic acid/potassium dichromate in the aqueous oxidizing agent solution is 1.2, preferably 2 or more. Oxidative polymerization under such conditions usually results in a conductivity of 10-1 S/
G or higher, often 10-3 to 10' S/eye
A conductive aniline oxidized polymer can be obtained.

As mentioned above, when a protonic acid aqueous oxidizing agent aqueous solution is added to an aqueous solution of an aniline water-soluble salt to cause a reaction, the concentration of protonic acid in the oxidizing agent aqueous solution is not particularly limited; , 1 to ION.

The oxidized aniline polymers obtained by the chemical oxidizing agents of aniline described above are insoluble in water and most solvents, but are usually slightly soluble or contain a portion that is soluble in concentrated sulfuric acid. The solubility in concentrated sulfuric acid varies depending on the reaction conditions for producing the polymer, but is usually in the range of 0.2 to 10% by weight, and in most cases in the range of 0.25 to 5% by weight. It is. However, it should be understood that this solubility, particularly in the case of high molecular weight polymers, may include portions of the polymer having a solubility in the above range.

The aniline oxidized polymer obtained as described above is usually obtained by adding 0.1 g/di solution of concentrated sulfuric acid to 0.1 g/di at 30°C.
It has a logarithmic viscosity in the range of ~1.0, in most cases 0.4
~0.6. In this case too, it is to be understood that, especially in the case of polymers of high molecular weight, the portion soluble in concentrated sulfuric acid has a logarithmic viscosity in the above range.

In addition, as described above, this aniline oxidized polymer contains emeraldine, 80% acetic acid, cold pyridine and N,N-
In sharp contrast to its solubility in dimethylformamide, the viscosity of a concentrated sulfuric acid solution of the tetrapolymer of the present invention was also much higher than that of emeraldine or aniline black under the same conditions; It is shown that the aniline oxidized polymer is a high molecular weight polymer. Furthermore, hydrothermal analysis also shows that the aniline oxidized polymer is a high molecular weight polymer.

In addition, the conductive aniline oxidized polymer that can be preferably used in the method of the present invention has an electrolytic potential higher than +1■ with respect to a standard calomel electrode when an aniline solution containing aniline and a protonic acid in an amount equivalent to or more than aniline is applied. It is obtained by electrolytic oxidation polymerization at a current density of 0.01 mA/c11 to LA/cd.

The protonic acid used in this electrolytic oxidative polymerization of aniline is preferably a protonic acid whose oxidation potential is higher than the oxidation potential in the present invention. Can be used.

By this electrolytic oxidative polymerization of aniline, 1O-6S/c
In order to obtain a conductive aniline oxidized polymer having a high electrical conductivity of m or more, the above protonic acid is used in an amount equal to or more than the equivalent of aniline, usually in the range of 1 to 50 times, and the aniline solution is mixed with a standard calomel electrode. It is necessary to perform electrolytic oxidative polymerization at a higher electrolytic potential than that of sheep. This is because when the oxidation electrolytic potential is below +1 V or when the current density is outside the above range, the resulting polymer has a low molecular weight and low conductivity.

Further, it is desirable that the aniline concentration in the aniline solution is 1% by weight or more. Even when the aniline concentration is less than 1% by weight, the resulting polymer has a low molecular weight,
It also has low conductivity. However, the upper limit of the aniline concentration is not particularly limited, but is usually up to 50% by weight.

The solvent is preferably a solvent that can dissolve both the protonic acid and aniline and whose decomposition potential is stable at the oxidation potential during electrolytic oxidative polymerization of aniline. Group lower alcohols, nitriles such as acetonitrile and benzonitrile, ketones such as methyl ethyl ketone, N, N-
Amides such as dimethylformamide are preferably used.

The decomposition potential of water is 1.23 V, which is higher than the electrolytic oxidation potential in the present invention in some cases, but in the present invention, even when water is used as a solvent, the oxidation electrolytic potential of aniline is lower than +l■. By increasing the oxidation value, it is possible to obtain a high molecular weight and highly conductive aniline oxidized polymer.

That is, the oxidation potential of aniline can be determined by a so-called cyclic portammogram in which the potential is scanned at a constant speed and the current value at each potential is plotted, but as shown in Figure 8, the oxidation potential for SCE is approximately 1■ Nearby,
Approximately 2v and approximately 3cm are observed. These oxidation potentials correspond to the oxidizing power of chemical oxidants; at each oxidation potential, polymers at that oxidation potential are preferentially produced, and in the middle of each oxidation potential, polymers at each oxidation potential are competitively produced. to be generated.

As explained earlier, Mohilner et al. performed electrolytic oxidation of aniline at an oxidation potential of +8 V relative to SCH in order to avoid electrolysis of water, but according to the present invention, the oxidation potential of +IV also has a high electrolytic potential, preferably 2~
By carrying out electrolytic oxidation at an electrolytic potential of 10 μm, it is possible to obtain an aniline oxidized polymer which has a molecular weight significantly higher than that of emeraldine and has high conductivity.

Current density in electrolytic oxidation is also important. Current density is 0
．． When it is less than 01 mA/c+fl, the obtained polymer is dissolved in concentrated sulfuric acid, so it is considered to be a low molecular weight polymer, and the conductivity of the drooping polymer is also low.

In the electrolytic oxidative polymerization of aniline, the aniline solution may contain a supporting electrolyte other than the above-mentioned prodocic acid. Specific examples include perchlorate metal salts such as lithium perchlorate and sodium perchlorate, and organic salts such as tetrabutylammonium perchlorate.

In addition to the above, salts such as nitrates, sulfates, hydrochlorides, tetrafluoroborates, hexafluorophosphates, etc. can also be used as supporting electrolytes.

In this way, the aniline oxidized polymer obtained by electrolytic oxidative polymerization of aniline usually has an electrical conductivity of 10-6 S/cm or more, often 10-'' to 10-1 S/cm. The aniline oxidation polymer obtained by Such aniline oxidized polymers are also insoluble in high molecular weight polymers, in sharp contrast to emeraldine, which is soluble in 80% acetic acid, cold pyridine, and N,N-dimethylformamide, as noted above. Furthermore, the differential thermal analysis results also indicate that the polymer insoluble in concentrated sulfuric acid is a high molecular weight polymer.

As explained above, conductive high molecular weight aniline oxidized polymers produced by chemical oxidative polymerization or electrolytic oxidative polymerization of aniline can be obtained as dry powders, and usually,
It exhibits a green to black edge color, and generally the higher the conductivity, the brighter the green color. However, pressure-molded products usually exhibit a shiny blue color.

Although the structure of the conductive high molecular weight aniline oxidized polymer produced by chemical oxidation or electrolytic oxidation of aniline explained above has not yet been determined, its infrared absorption spectrum is similar to that of emeraldine, while it has a high molecular weight and high conductivity. Therefore, it appears to be a substantially linear π-electron conjugated polymer as shown in the following formula, in which aniline continuously forms a polymer chain through head-to-tail bonds.

(III) All of these aniline oxidized polymers have high electrical conductivity, but the electrical conductivity is significantly reduced by compensating with ammonia, and the original high electrical conductivity can be restored by doping again with sulfuric acid. From this, it is confirmed that doping with protonic acid has already occurred at the stage of oxidative polymerization. In addition, the infrared absorption spectrum of the polymer that was compensated with ammonia and then doped again with sulfuric acid completely matched that of the polymer before compensation with ammonia. It is confirmed that Furthermore, due to the fact that the polymer is compensated with ammonia and the sign of the thermoelectromotive force, this polymer is p-type.

As described above, the conductive high molecular weight aniline oxidized polymer obtained by chemical oxidative polymerization or electrolytic oxidative polymerization of aniline according to the present invention has already been doped with a protonic acid at the polymerization stage, so that new doping is required. It has high conductivity without the need for treatment, and even if left in the air for a long period of time, its conductivity does not change at all. In comparison, it has a uniquely high stability.

Next, a method for manufacturing a conductive material using the conductive aniline oxidized polymer described above as a raw material will be described.

According to the present invention, by firing such an aniline oxidized polymer, a material with even higher conductivity can be obtained.

The conductive material according to the present invention is obtained by calcining an aniline oxidized polymer at a temperature of 700°C or higher in an inert atmosphere or under vacuum, and usually has a conductivity in the range of 10-1 to 103 S/am. .

In the method of the present invention, water and hydrogen are desorbed from the aniline oxidized polymer as well as doping components in the calcination step up to about 400°C, and at a temperature of about 400°C, its electrical conductivity is significantly reduced. do. By subsequently firing the polymer at a temperature of 700°C or higher in an inert atmosphere or under vacuum, the aromatic rings of the polymer are condensed and bonded to each other, forming a so-called graphite precursor, which increases its electrical conductivity. It is possible to obtain a conductive material according to the present invention having: Therefore, calcination at temperatures up to about 400° C. does not necessarily have to be carried out in an inert atmosphere or under vacuum, but may also be carried out in an oxidizing atmosphere, for example in air.

The upper limit of the firing temperature is 3000°C. Even if it is fired at a temperature higher than this, no particular improvement in conductivity is observed. Firing is usually carried out at temperatures up to 2000°C. As the inert atmosphere, an atmosphere of argon, helium, neon, nitrogen, etc. can be used. Further, when firing is performed under vacuum, the atmosphere is preferably the above-mentioned inert atmosphere, but air may be used.

In the present invention, since the aniline oxidation polymer described above is obtained in the form of a powder, a conductive material can be obtained as a molded article by press-molding this powder into a predetermined shape and firing it. In such molding, the polymer powder is usually molded into a predetermined shape, for example, a sheet, under a pressure of 4,500 to 6,000 kg/cJa. As described above, according to the present invention, since the polymer does not undergo phase change during the firing process, a conductive material can be obtained without changing the shape of the molded product.

Furthermore, in the present invention, as described above, when an electrically conductive material is obtained by firing an aniline oxidized polymer, when this polymer dissolves in concentrated sulfuric acid, or contains a portion that dissolves in concentrated sulfuric acid, It is preferable that the obtained aniline oxidized polymer is purified by reprecipitating in advance from concentrated sulfuric acid, and then calcined to obtain the conductive material according to the present invention. The conductive aniline oxidation polymer obtained by the above-mentioned aniline chemical oxidation polymerization or electrolytic oxidation polymerization may contain low molecular weight substances as a result of thermogravimetric analysis and differential thermal analysis. This solution is added to a precipitant, that is, a poor solvent for the polymer to reprecipitate the polymer, thereby removing these low molecular weight substances, and then calcining according to the present invention.

In this way, prior to calcination of the aniline oxidized polymer, the polymer was purified by a reprecipitation method using concentrated sulfuric acid, and
By press-molding it into a predetermined shape and firing it, it is possible to obtain a molded article of conductive material with a smooth and glossy surface.Furthermore, the conductive ring of this material is higher than that of the case where the polymer powder is not purified. It's more expensive. When a polymer powder is molded and fired without performing such a purification treatment, the surface of the resulting conductive molded product is dull and uneven.

As mentioned above, the conductive oxidized aniline polymer obtained by chemically oxidizing aniline usually dissolves in concentrated sulfuric acid, albeit slightly, and in most cases, it dissolves at about 1%, so it can be easily dissolved by the reprecipitation method. Also in purification, it is preferable to dissolve about 1% in concentrated sulfuric acid. However, for example, when obtaining an oxidized polymer of aniline by electrolytic oxidation polymerization, it is possible to obtain a polymer that dissolves in concentrated sulfuric acid at a high concentration depending on the conditions. 1%
It may be dissolved in the above amount. As a precipitating agent for reprecipitating the polymer, any precipitating agent can be used without particular restriction as long as it is miscible with sulfuric acid, but considering the ease of post-treatment, relatively It is preferable to use a solvent with a low boiling point, and therefore, for example, water, acetone, alcohol, etc. are preferably used. It is preferable to use such a precipitant in an amount of 5 times or more the amount of the sulfuric acid solution of the polymer.

The reprecipitated polymer is separated by filtration, washed with water, and washed with a solvent.
Just dry it.

The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 (11 Preparation of aniline oxidized polymer by chemical oxidation 300
Put 45g of water in a ml flask and add 4ml of concentrated hydrochloric acid.
was added, and 5 g (0,0537 mol) of aniline was further dissolved to prepare an aqueous aniline hydrochloride solution.

Separately, 4.61 g of concentrated sulfuric acid (0,(
1'4' 7 mol) and further potassium dichromate 1
．． Oxidizing agent aqueous solution in which 84g (0,00625 mol) was dissolved (protonic acid/potassium dichromate molar ratio 7.5)
was prepared and added dropwise to the aqueous aniline hydrochloride solution with stirring at room temperature over a period of 30 minutes.

After the start of dropping, the solution was only colored yellow for the first 2 to 3 minutes, but after that, a green solid precipitated out immediately.
The reaction solution had a black border color.

After the addition was completed, the mixture was stirred for an additional 30 minutes, and then the reaction mixture was poured into 400 ml of acetone, stirred for 2 hours, and then the polymer was filtered off. The resulting polymer was washed with stirring in distilled water, filtered off, and washing was repeated in this manner until the filtrate became neutral. Next, the filtered polymer was washed repeatedly with acetone until the filtrate was no longer colored. The filtered polymer was vacuum dried over phosphorus pentoxide at room temperature for 10 hours to obtain a conductive aniline oxidized polymer as a green powder.

(2) Figure 1 shows the infrared absorption spectrum of the polymer obtained in the evaluation of the physical properties of the aniline oxidized polymer. For comparison, the infrared absorption spectra of Emeraldine and commercially available Diamond Black are shown in Figures 2 and 3, respectively. In addition, emeraldine was prepared by the method of A, G, Green et al.
t at,, J,' Chew, Soc, 97+2
38B (1910)).

This polymer was added to 97% concentrated sulfuric acid at room temperature,
When I stirred it and checked its solubility, the amount dissolved was 1.2.
% by weight. Further, the logarithmic viscosity of a 97% concentrated sulfuric acid solution of this polymer at a concentration of 0.5 g/di at a temperature of 30° C. was 0.46. For comparison, the viscosities of Emeraldine and Diamond Black under the same conditions are 0.02 and 0.02, respectively. It was O05.

Furthermore, the results of thermogravimetric analysis in air of the above polymer and emeraldine are shown in FIG. The temperature increase rate is 10°C/min.

Next, about 120 μg of the polymer powder obtained above was crushed in a gIzui preparation mortar, and then used in an infrared spectrophotometer tablet molding machine under a pressure of 60 μm.
00 kg/c+a to form a disk with a diameter of 130 mm. Four pieces of copper foil with a width of about 1ml1 were glued to the four corners of a silver paste or graphite paste T disk, and the conductivity was measured according to the van der Pouw method in air, and the conductivity was 0.
．． It was 4O3/e11. '10-2
Even when measured in a vacuum of Torr, they showed almost the same conductivity. This disk was left in air for 4 months with virtually no change in conductivity.

Further, FIG. 5(B) shows an infrared absorption spectrum when the above polymer is compensated with ammonia, and FIG. 5(C) shows an infrared absorption spectrum after doping the polymer again with 5N sulfuric acid. The spectrum after this redoping is the fifth
It is exactly the same as the original shown in Figure (A), and furthermore, the conductivity is also the same as before the ammonia compensation. This shows that the polymer according to the invention is already doped by the protic acid used in its oxidative polymerization stage.

(3) Preparation of conductive material by firing (Experiment No. 1) The aniline oxidized polymer obtained above was pressure-molded into a diameter of 13 pieces at a pressure of 6000 kg/- and fired at 90θ°C for 15 minutes under a nitrogen stream. The conductivity of the obtained conductive material is 0.40S/
It was Cal.

Similarly, conductive materials were obtained by firing under various conditions shown in the table. The electrical conductivity is shown in the table. In Experiment No. 9, argon gas was introduced into the firing container, and then firing was performed by reducing the pressure to a predetermined pressure ratio. Further, the measurement of electrical conductivity is the same as described above.

(Note) (1) It was baked in advance at 300°C for 1 hour in air.

(2) The argon atmosphere was reduced to 10-'Torr.

Example 2 The thermogravimetric analysis curve (TGA) and differential thermal analysis curve (DTA) of the aniline oxidized polymer prepared in Example 1 were
As shown in the figure. Large peaks are seen at 425°C and 539°C.

This polymer was dissolved in concentrated sulfuric acid to form a 0.8% by weight solution, which was then added to a large amount of acetone to reprecipitate the polymer. After the polymer was filtered through a glass filter, it was washed with water and then with acetone in the same manner as in Example 1, and vacuum dried to obtain a purified polymer powder. TGA of this oxidized polymer
and DTA are shown in FIG. The above peak was not observed, and low molecular weight substances were removed. This was molded into a disk in the same manner as in Example 1, and the conductive ring was measured.
．． It was 7×10-”S/am.

The unpurified polymer and the purified polymer were fired simultaneously in an electric furnace at 900° C. for 15 minutes under a nitrogen stream. When the purified polymer was used, the conductive material obtained had a completely smooth surface with a conductive ring of 60 S/cm, but when the unpurified polymer powder was used, there were many conductive rings on the surface. Asperities were observed, and the conductive ring was 24S/a++.゛Also, the purified polymer was heated for 1400 min under an argon stream.
C. for 15 minutes. The conductive ring of the obtained conductive material was 135 S/am.

Example 3 (11 Production of aniline oxidized polymer by electrolytic oxidation) An anode and a cathode made of platinum were inserted into an aqueous solution in which the aniline concentration was 5% by weight and contained 8 times the equivalent of sulfuric acid to aniline. Electrolytic oxidation polymerization was carried out by applying current for 2 hours at an electrolytic potential of +2.0 V and a constant current density of 5 mA/ctl.In addition, when electrolytic polymerization is performed at a constant current density like this, it is common for the electrolytic potential to gradually increase. This is well known, and therefore, the electrolytic potential is usually expressed as the initial potential as described above.

The aniline polymer produced on the anode in the above reaction was peeled off and pulverized, washed with stirring in distilled water, filtered, and then the filtered polymer was washed with acetone. The filtered polymer was vacuum dried over phosphorus pentoxide at room temperature for 10 hours to obtain a conductive aniline oxidized polymer as a green powder.

Incidentally, FIG. 8 shows the cyclic voltamodalum in electrolytic oxidation of aniline.

(2) Evaluation of physical properties of aniline oxidized polymer The obtained polymer was found to be insoluble not only in concentrated sulfuric acid but also in N-methyl-2-pyrrolidone. The infrared absorption spectrum of this aniline oxidized polymer is shown in FIG.

Furthermore, the results of thermogravimetric analysis in air of the above polymer and emeraldine are shown in FIG. The temperature increase rate is 10°C/min.

Next, in the same manner as in Example 1, approximately 120 μm of the polymer powder obtained above was pressure-molded into a disk with a diameter of 131 m at a pressure of 6000 kg/cd, and the mass was measured in air according to the van der Pouw method. As a result, the conductive ring was 2.6 S/cIn. Measurements in a vacuum of 10-'' Torr showed nearly the same conductive ring. The disk was left in air for 4 months and the conductive ring remained essentially unchanged.

In addition, in the same manner as the aniline oxidation polymer obtained in Example 1, the aniline oxidation polymer was also subjected to electrolytic oxidation. It was confirmed that it was doped with sulfuric acid at the stage.

(3) Pressure molding the aniline oxidized polymer powder obtained in the preparation of conductive material by firing in the same manner as in Example 1,
This was baked at 900° C. for 15 minutes under a nitrogen stream. The conductive ring of the obtained conductive material was 41S/port.

[Brief explanation of the drawing]

Figure 1 shows the infrared absorption spectrum of the aniline oxidized polymer obtained by chemically oxidizing aniline, Figures 2 and 3 show the infrared absorption spectra of emeraldine and aniline black, respectively, and Figure 4 shows the infrared absorption spectra of the above polymer and emeral black. It is a graph showing the weight residual rate of Dein due to heating. Figure 5 shows the above polymer (A), a polymer (B) obtained by compensating this polymer with ammonia, and a polymer (C) obtained by redoping the polymer of (B) with sulfuric acid. This is the infrared absorption spectrum of FIG. 6 shows the thermogravimetric analysis curve and differential thermal analysis curve of the aniline oxidized polymer, and FIG. 7 shows the thermogravimetric analysis curve and differential thermal analysis curve after the aniline oxidized polymer was purified by reprecipitation with sulfuric acid. Figure 8 is a cyclic portammogram for electrolytic oxidation of aniline, Figure 9 is an infrared absorption spectrum of an oxidized polymer obtained by electrolytic oxidation of aniline, and Figure 10 is the weight of this aniline oxidized polymer and emeraldine after heating. It is a graph showing the residual rate.

Claims (3)

[Claims] (1) Consisting of a fired product of a high molecular weight aniline oxidized polymer,
An electrically conductive material having an electrical conductivity of 10^-^1 S/cm or more. (2) A high molecular weight aniline oxidized polymer is fired at a temperature of 700°C or higher in an inert atmosphere or under vacuum to achieve an electrical conductivity of 10.
^-^ A method for producing a conductive material characterized by obtaining a conductive material of 1 S/cm or more. (3) High molecular weight aniline oxidized polymer has electrical conductivity of 10^-^
3. The method for producing a conductive material according to claim 2, wherein the conductive material is 1^0 S/cm or more.