JPH0423825A - Water-soluble electroconductive polymer and its production - Google Patents

Abstract

PURPOSE:To obtain the title water-soluble polymer capable of being synthesized inexpensively, readily and in a large amount, having excellent processing properties, advantageously in production on an industrial scale, by subjecting pyrrole to chemical oxidative polymerization in the presence of a water-soluble polymer protonic acid. CONSTITUTION:(A) 1mol pyrrole or derivative thereof is subjected to chemical oxidative polymerization in the presence of (B) a water-soluble polymer protonic acid having 50,000-1,500,000 molecular weight or salt thereof in an amount to give 0.5-5mol acid or basic group by using (C) 0.2-10mol, based on 1mol component A, of an oxidizing agent to give the objective polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a water-soluble conductive polymer and a method for producing the same.

(Prior Art) It is well known that when pyrrole or its derivatives are subjected to electrolytic oxidative polymerization or chemical oxidative polymerization, such polymers (hereinafter referred to as polypyrroles) can be easily obtained.

Using electrolytic oxidative polymerization, polypyrroles with excellent conductivity can be obtained in the form of a film on an electrode, but it is not suitable for mass production. When polymerized (chemical oxidative polymerization), polypyrroles can be obtained in the form of powder in large quantities and at low cost, although the conductivity is poor. However, polypyrroles obtained by electrolytic oxidation or chemical oxidation are generally insoluble and infusible, so they have problems such as being difficult to mold and use them in any desired form. .

(Problems to be Solved by the Invention) The present invention has been made against the background of the above-mentioned conventional technical problems, and it provides polypyrroles with processability, particularly water solubility, which has been difficult to obtain in the past, and the production thereof. This was done with the aim of providing a method at a low cost.

(Means for Solving the Problem) As a result of various studies to achieve the above object, the present inventors found that the amount of acid group or base is 0.5 to 5 moles per mole of pyrrole or its derivative. Prepare a water-soluble polymer protonic acid or its salt, and in the presence of the water-soluble polymer,
Chemical oxidative polymerization is carried out using 0.2 to 10 moles of an oxidizing agent per mole of pyrrole or its derivative. The polymer obtained by the above method contains an anion of the water-soluble polymeric protonic acid or a salt thereof as a dopant, and
It was discovered that the conductive polymer contains 0.3 to 5 moles of monomer units of the water-soluble polymer per 1 mole of monomer units of the oxidized polymer, and that this polymer is water-soluble. This is what we have come to.

The dopant used in the present invention is an anion of a water-soluble polymeric protonic acid or a salt thereof having a molecular weight of 50,000 to 1,500,000. Examples of water-soluble polymeric protonic acids include polystyrene sulfonic acid, polyvinylsulfonic acid, polymethacrylsulfonic acid, and poly-2-acrylamido-2-methylpropanesulfonic acid. Examples include their alkali metal salts such as sodium and potassium, and alkyl ammonium salts such as trimethylammonium, monotriethylammonium, tetramethylammonium, and tetraethylammonium.

The molecular weight of these water-soluble polymers is preferably 50,000 to 1,500,000; if it falls below this range, it will be difficult to impart water solubility, and if it exceeds this range, although water solubility can be imparted, When dissolved in
It becomes difficult to handle. In addition, the amount of the water-soluble polymer protonic acid or its salt used is usually such that the acid group or base of the water-soluble polymer is 0 per mole of pyrrole or its derivative.
．． It is used in an amount of 5 to 5 moles. If it is below this range, it will be difficult to impart water solubility to the polypyrroles, and if it is above this range, although it will be easily dissolved in water, its electrical conductivity will be extremely low.

Since not all of the acid groups or bases of the above-mentioned water-soluble polymeric protonic acids or their salts can be used as dopants, it is also possible to use inorganic anions or organic low-molecular anions as dopants to improve their conductivity. It is.

Specifically, halogen anions such as chlorine, bromine, and iodine, halide anions such as hexafluoroline, hexafluoroline, and tetrafluoroborine, sulfonic acid anions such as benzenesulfonic acid and p-toluenesulfonic acid, Examples include perchloric acid anions such as perchloric acid and potassium perchlorate, and sulfuric acid anions such as sulfuric acid, and these can be used alone or in combination with the anion of the water-soluble polymeric protonic acid or its salt. can.

The pyrrole or its derivative used in the present invention is pyrrole,
Examples include N-alkylpyrroles such as N-methylpyrrole and N-ethylpyrrole, N-arylpyrroles such as N-phenylpyrrole, and 3-alkylpyrroles such as 3-methylpyrrole and 3-ethylpyrrole. It is not limited.

Next, the method for producing the water-soluble conductive polymer of the present invention will be explained. The water-soluble conductive polymer can be obtained by chemical oxidative polymerization of pyrrole or its derivative in the presence of a water-soluble polymeric protonic acid or its salt. Chemical oxidative polymerization methods include dissolving pyrrole or a pyrrole derivative and a water-soluble polymeric protonic acid or its salt in a reaction solvent, and adding an oxidizing agent or its solution; Examples include, but are not limited to, a method of adding pyrrole, a conductor thereof, or a solution thereof to a solution containing the agent.

The oxidizing agents used in the chemical oxidative polymerization of the present invention include metal halides such as ferric chloride, boron trifluoride, antimony pentafluoride, and aluminum chloride, peroxides such as hydrogen peroxide and peracetic acid, and persulfuric acid. , persulfate and its salts such as potassium persulfate and ammonium persulfate, iodic acid and its salts such as potassium perchlorate, potassium permanganate, transition metal compounds such as chromic acid, etc. may be used alone or in combination.

The reaction solvent used in the chemical oxidative polymerization of the present invention is not particularly limited, but any solvent may be used as long as it can disperse, preferably dissolve, pyrrole or pyrrole derivative and water-soluble polymeric protonic acid or its salt, and is not oxidized by an oxidizing agent. .

As such a reaction solvent, one type or a mixture of two or more of water or organic solvents can be used, and examples of the organic solvent include alcohols such as methanol and ethanol, nitriles such as acetonitrile, and ethers such as tetrahydrofuran. , halogenated hydrocarbons such as chloroform and dichloromethane, hydrocarbons such as hexane and toluene,
Ketones such as acetone can be mentioned.

The amount of the oxidizing agent used during polymerization is preferably 0.2 to 10 moles per mole of pyrrole or pyrrole derivative. If it is below this range, the conductivity of water-soluble polypyrroles will be low, and if it is above this range, although water-soluble polypyrroles can be obtained, the oxidizing agent will be used in large excess, which will be economically disadvantageous.

Further, the amount of the reaction solvent used is preferably such that the concentration of the water-soluble polymeric protonic acid or its salt is relatively low, such as about 100 g/l or less. When chemical oxidative polymerization is carried out at high concentrations, the reaction mixture turns into a gel, making it difficult to obtain water-soluble polypyrroles.

The polymerization temperature is not particularly limited as long as it is below the boiling point of the reaction solvent, but is preferably between 0°C and room temperature. Although water-soluble polypyrroles can be obtained outside this range, the conductivity decreases above room temperature, and below 0°C, much energy is required for cooling, which is economically disadvantageous.

In the chemical oxidative polymerization of the present invention, the conductivity of the water-soluble conductive polymer is improved by allowing the inorganic anion or organic low-molecular anion to coexist in the reaction solvent together with the water-soluble polymeric protonic acid or its salt. You can also do it.

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

Example 1 20% aqueous solution of sodium polystyrene sulfonate (Polinas PS-50 manufactured by Tosoh Corporation, molecular weight 400,000 to 600,000) 10 g (-8O3Na group 9.7 mmol), pyrrole 0.135 g (2 mmol) and water 30 ml The capacity 1
A homogeneous solution was prepared by charging the mixture into a 00ml reaction flask. This aqueous solution was cooled to 0 to 2°C, and a solution prepared by dissolving 0.228 g (1 mmol) of ammonium persulfate in 10 ml of water was added dropwise while stirring. After stirring for 1 hour after the dropwise addition, the reaction solution became black and opaque. After filtration, no solid matter remained on the filter paper. The filtrate was poured into ethanol, and the precipitate was separated by filtration and vacuum-dried to obtain water-soluble polypyrrole as a black-gray powder. This powder is pressed into a tablet molding machine at a pressure of 6
It was press-molded into a disk with a diameter of 13 mm at a pressure of 0.00 kg/cm2, silver paste was applied to both sides, and the conductivity was measured by the two-terminal method, and it was found to be 6 x 10-5 s/cm. Moreover, it was dissolved in water by 20% or more. As a result of elemental analysis, the number of moles of the water-soluble polymer monomer unit per mole of the oxidized polymer (polypyrrole) monomer unit in the water-soluble conductive polymer (hereinafter 1) y/803 kt.

) was 1/4.0.

Example 2 In Example 1, the amount of ammonium persulfate used was 0.4
Water-soluble polypyrrole was obtained as a black powder in exactly the same manner as in Example 1 except that the amount was 56 g (2 mmol). The conductivity of this powder was 2XIO-4s/cm, and it dissolved in water at 1% or more.

Moreover, the py/5Oa-ratio was 1/2.6.

Example 3 Water-soluble polypyrrole was prepared in the same manner as in Example 2, except that 10 g of a 20% aqueous solution of sodium polystyrene sulfonate (Polinus PS-5, manufactured by Tosoh Corporation, molecular weight 50,000 to 100,000) was used. Obtained as a black powder.

The electrical conductivity of this powder was 6×10 −4 s/cm, and it was dissolved in water by more than 1%. Also, the pY/5Oa-ratio is 1/4.5
Example 4 20% aqueous solution of sodium polystyrene sulfonate (Polinus PS-1001 manufactured by Tosoh Corporation, molecular weight 800,000 to 1
200,000) 3.09g (-8O3Na group 3Na),
A homogeneous solution was prepared by charging 0.201 g (3 mmol) of pyrrole and 57 ml of water into a 100 ml reaction flask. This aqueous solution was cooled to 0 to 2°C, and while stirring, 0.685 g (3 mmol) of ammonium persulfate was added to 15 ml of water.
The solution was dissolved in ml and added dropwise. After stirring for 1 hour after the dropwise addition, the reaction solution turned black. No solid matter remained on the filter paper after filtration. The filtrate was poured into acetonitrile, and the precipitate was separated by filtration and vacuum dried to obtain water-soluble polypyrrole as a black powder. The conductivity of this material is 2×10″″3s/c
m and dissolved in water at 1% or more. Moreover, the py/5o3-ratio was 110.4.

Example 5 100 g of a 20% aqueous solution of sodium polystyrene sulfonate (the above Polynas PS-50) was diluted to about 21% with water, and diluted with cation exchange resin (Diaion 5K manufactured by Mitsubishi Kasei Corporation).
-IB) to obtain a polystyrene sulfonic acid aqueous solution. This aqueous solution was concentrated to a constant volume of 250ml. This aqueous solution was subjected to neutralization titration with IJium (hydroxide), and the concentration of sulfonic acid groups was determined to be 0.39 mol/1.

1.34 g (20 mmol) of pyrrole, 25 ml of the above polystyrene sulfonic acid aqueous solution (10 mmol of SO3H groups), and 20 ml of water were placed in a 100 ml reaction flask to prepare a homogeneous solution. This solution was cooled to 0 to 3°C, and 1.6 g (7 mmol) of ammonium persulfate dissolved in 30 ml of water was added dropwise while stirring. After the addition, the mixture was stirred for 1 hour, and the resulting black solution was diluted with water and filtered, leaving almost no solid matter on the filter paper. The filtrate was poured into inpropyrrole alcohol, and the precipitate was filtered off and dried under vacuum to obtain water-soluble polypyrrole.

The conductivity of this material was 7×10 −3 s/cm, and the solubility in water was 1% or more. Also, py/503-
The ratio was 110.38.

Example 6 20 g (-8
O3H group 9.7 mmol), N-methylpyrrole 0.4
05 g (5 mmol) and 30 ml of water in a volume of 100 m
The mixture was charged into the reaction flask No. 1 and cooled to 0 to 5°C. While stirring, add 1.14 g (5 mmol) of ammonium persulfate to 2 ml of water.
0ml of the dissolved liquid was added dropwise. After stirring for 1 hour after the dropwise addition, the reaction solution turned black. After filtration, almost no solid matter remained on the filter paper. Pour the filtrate into ethanol,
The precipitate was filtered and dried under vacuum to obtain water-soluble polyN-methylpyrrole as a black powder.

The conductivity of this material was 8×10 −5 s/cm, and it dissolved in water by 1% or more. Also, the py/5o3-ratio is 171.5
Met.

Comparative Example 1 The reaction was carried out in exactly the same manner as in Example 4, except that a 20% aqueous solution of sodium polystyrene sulfonate (Polynas PS- manufactured by Tosoh Corporation, molecular weight 10,000 to 30,000) was used. When the liquid was filtered, water-insoluble polypyrrole powder remained on the filter paper. This product was insoluble in water and had a py/503 ratio of 0.28. Further, the filtrate was poured into ethanol, and the precipitate precipitated was separated by filtration and dried to obtain black polypyrrole.

This product had a py/503 ratio of 0.45, but was hardly soluble in water.

Comparative Example 2 An electrolytic solution consisting of 20% aqueous solution of sodium polystyrene sulfonate (Polinas PS-50) Log (9.7 mmol of -8O3Na groups), 0.85 g (9.7 mmol) of pyrrole, 29 ml of water, and 10 ml of acetonitrile was prepared. did. Using stainless steel electrodes for both negative and positive electrodes, 1
Galvanostatic electrolysis was performed for 45 min at a current density of mA/cm2. The polypyrrole film deposited on the anode was peeled off from the electrode to obtain a self-supporting film. The film was flexible while wet but became brittle when dry.

The conductivity was 1.6 s/cm, and the ratio 3'/SO3 was 0.2. Moreover, it did not dissolve in water at all.

Therefore, it is difficult to obtain water-soluble conductive polymers by electrolytic oxidation polymerization.

(Effects of the Invention) In the present invention, an anion of a water-soluble polymeric protonic acid or a salt thereof is used as a dopant for polypyrroles. At this time, by specifying the molecular weight of the water-soluble polymer and the ratio of the monomer unit of the water-soluble polymer to the monomer unit of the polypyrrole, the polypyrrole becomes water-soluble, and since it has excellent processability, various It can be used for various purposes.

Furthermore, since the method for producing polypyrroles of the present invention is based on chemical oxidative polymerization, large-scale synthesis is possible at low cost and easily, which is advantageous in production on an industrial scale.

Claims (2)

[Claims] (1) A polymer obtained by chemical oxidative polymerization of pyrrole or its derivative contains an anion of a water-soluble polymeric protonic acid or a salt thereof having a molecular weight of 50,000 to 1,500,000 as a dopant, and A water-soluble conductive polymer containing 0.3 to 5 moles of monomer units of the water-soluble polymer per mole of monomer units. (2) A molecular weight of 50,000 to 150 so that the acid group or base is 0.5 to 5 mol per 1 mol of pyrrole or its derivative.
Ten thousand water-soluble polymeric protonic acids or their salts are prepared, and chemical oxidative polymerization is carried out using 0.2 to 10 moles of an oxidizing agent per mole of pyrrole or its derivative in the presence of the water-soluble polymer. A method for producing a water-soluble conductive polymer, characterized in that: