JP2819692B2 - Method for producing conjugated polymer - Google Patents

Description

The present invention relates to a method for producing a conjugated polymer having high conductivity. This polymer is useful as a conductive polymer.

<Conventional technology> The conjugated polymer obtained by the present invention has a structure crosslinked by a conjugated chain. Until now, polyacetylene, poly-p-phenylene, polythiophene, polypyrrole,
Many conjugated polymers such as poly-p-phenylenevinylene and poly-2,5-thienylenevinylene are known. Further, many methods for producing these compounds have been studied, and polymerization using a catalyst, electrochemical polymerization, a method using a soluble polymer intermediate, and the like have been reported. As a method of obtaining a conjugated polymer having high conductivity, a method of reducing defects in a conjugated chain,
A method of highly aligning conjugated molecules has been proposed. Also,
It is also known to copolymerize two or more monomers, but no improvement in electric conductivity (hereinafter referred to as electric conductivity) was found by copolymerization.

Further, as the conjugated polymer crosslinked for the purpose of improving the mechanical strength of the conjugated polymer, polydiacetylene bonded with a urethane group is known.

<Problems to be Solved by the Invention> However, it is said that the temperature dependence of the conductivity is semiconducting and the intermolecular conduction of the carrier is rate-determining in the known conductive polymers. . In order to improve conductivity, intermolecular conduction must be reduced as much as possible. Since the conjugated system has a structure in which the conjugate system is spread two-dimensionally, this point graphite is less affected by intermolecular conduction and has high conductivity.

As described above, a conjugated polymer that is less affected by intermolecular conduction has been demanded.

An object of the present invention is to provide a method for producing a three-dimensionally crosslinked conjugated polymer capable of conducting a carrier.

The present invention <Means for Solving the Problems> the general formula _{^{(1) X 1 - G '}} + -CH 2 -R 1 -CH 2 -G' + X 1 - ... (1) R 1: - Group forming a continuous carbon-carbon conjugated system with CH = CH- R ₂ , R ₃ : a hydrocarbon group having 1 to 20 carbon atoms, R ₄ : a bifunctional hydrocarbon group having 4 to 20 carbon atoms X ₁ ⁻ : a bifunctional monomer represented by the formula: ) R ₅ CH ₂ -G ″ ⁺ X ₂ ⁻ ) _n (2) R ₅ : a group forming a continuous carbon-carbon conjugated system with —CH ＝ CH— R ₆ , R ₇ : a hydrocarbon group having 1 to 20 carbon atoms; R ₈ : a bifunctional hydrocarbon group having 4 to 20 carbon atoms; X ₂ ⁻ : a counter ion n: an integer of 3 or more; A method for producing a conjugated polymer, comprising subjecting a conjugated polymer precursor obtained by copolymerizing the above monomer to desulfonium salt treatment in an inert atmosphere is provided.

 Hereinafter, the present invention will be described in detail.

The monomer used in the present invention includes a bissulfonium salt having a group forming a continuous carbon-carbon conjugated system with -CH = CH- shown in the general formula (1) and- It has three or more sulfonium bases having a group forming a continuous carbon-carbon conjugated system with CH = CH-. In the general formula (1), R ₁ is a group that forms a continuous carbon-carbon conjugated system with —CH ＝ CH— and has 6 carbon atoms.
To 14 aromatic hydrocarbons and their nuclear-substituted products, or C 4 to C 13 heterocyclic aromatic compounds and their nuclear-substituted products.
These substituents are not particularly limited, but have 1 to 1 carbon atoms.
A hydrocarbon group having 10 and an alkoxy group having 1 to 10 carbon atoms are preferred. R ₁ group is p-phenylene, 2,5-dimethoxy-p-phenylene, 2,5-diethoxy-p-phenylene, 2,5-dimethyl-p-phenylene, 2,6-naphthalenediyl, 2,5
-Thienylene, 3-methyl-2,5-thienylene, 3-methoxy-2,5-thienylene, 2,5-furandiyl and the like. Particularly, p-phenylene and 2,5-thienylene are preferable. R ₂ and R ₃ are a hydrocarbon group having 1 to 10 carbon atoms, for example, methyl, ethyl, propyl, isopropyl, n-butyl, 2-ethylhexyl, phenyl, cyclohexyl,
Examples thereof include a benzyl group, and a hydrocarbon group having 1 to 6 carbon atoms, particularly, a methyl or ethyl group is preferred. R ₄ has _{4 or more} carbon atoms
Examples thereof include ten bifunctional hydrocarbon groups, for example, tetramethylene, pentamethylene, and hexamethylene groups. Among them, hydrocarbon groups having 4 to 6 carbon atoms, particularly, tetramethylene and hexamethylene groups are preferable.

Counterion X ₁ of sulfonium salts ^- can be used any of the conventional methods. For example, halogen, hydroxyl group, boron tetrafluoride, perchloric acid, carboxylic acid, sulfonic acid ion and the like can be used. Among them, chlorine, bromine,
Halogen ions such as iodine are preferred.

The monomer represented by the general formula (2) functions as a crosslinking agent. R ₅ is a group that forms a continuous carbon-carbon conjugated system with —CH ＝ CH—, and is an aromatic hydrocarbon having 6 to 14 carbon atoms and a nuclear substituent thereof, or a heterocyclic aromatic having 4 to 13 carbon atoms. Group compounds and their nuclear substituents. These substituents are not particularly limited, but may be a hydrocarbon group having 1 to 10 carbon atoms,
~ 10 alkoxy groups are preferred. R ₅ group is benzenetriyl, benzenetetrayl, 2-methoxy-benzenetriyl, 2-ethoxy-benzenetriyl, 2-methyl-
Examples thereof include benzenetriyl, naphthalenetriyl, and naphthalenetetrayl. Particularly, benzenetetrayl is preferred. R ₆ and R ₇ are a hydrocarbon group having 1 to 10 carbon atoms, for example, methyl, ethyl, propyl, isopropyl, n-butyl,
2-ethylhexyl, phenyl, cyclohexyl, benzyl group and the like, and a hydrocarbon group having 1 to 6 carbon atoms,
Particularly, methyl and ethyl groups are preferable. R ₈ is a bifunctional hydrocarbon group having 4 to 10 carbon atoms, for example, tetramethylene, pentamethylene, hexamethylene group and the like.
To 6 hydrocarbon groups, particularly tetramethylene and hexamethylene groups.

Counterion X ₂ sulfonium salts ^- it can be used any of the conventional methods. For example, halogen, hydroxyl group, boron tetrafluoride, perchloric acid, carboxylic acid, sulfonic acid ion and the like can be used. Among them, chlorine, bromine,
Halogen ions such as iodine are preferred.

The polymer intermediate is prepared by mixing the bissulfonium salt represented by the general formula (1) and the polysulfonium salt represented by the general formula (2) with water alone or an organic solvent soluble in water, for example, alcohols. Can be obtained by condensation polymerization using an alkali in a mixed solvent of Preferably, water alone,
Alternatively, it is effective to carry out polymerization in a mixed solvent of water and an alcohol soluble in water.

The addition ratio of the bissulfonium salt represented by the general formula (1) and the polysulfonium salt represented by the general formula (2) can be selected at an arbitrary ratio. It is preferable to appropriately select the ratio in consideration of the number of groups. For example, if the proportion of the polysulfonium salt represented by the above general formula (2) is too large, it is extremely crosslinked, insolubilized, and is not preferable in terms of shapeability. On the other hand, if the amount is too small, the crosslinking effect does not appear, which is not preferable. The molar ratio of the monomer (1) to the crosslinking agent (2) used is in the range of 1: 1 to 1: 0.005, preferably 1: 0.1 to 1: 0.01.

The bissulfonium salt represented by the general formula (1) and the polysulfonium salt represented by the general formula (2) may be added at any point in time. It is preferable to appropriately select the addition time in consideration of the above. Polymerization may be carried out by adding both from the beginning, or when the rate of polymerization of the polysulfonium salt alone represented by the general formula (2) is high, the polymerization of the bissulfonium salt represented by the general formula (1) may occur to some extent. It is effective to add the polysulfonium salt of the above general formula (2) at the time of progress.

The alkaline solution used for the condensation polymerization is preferably a strong basic solvent having a pH of 11 or more in an organic solvent which does not react with water or a monomer, for example, a mixed solvent of alcohols and water. Calcium, quaternary ammonium salt hydroxide, sulfonium salt hydroxide, strong basic ion exchange resin (OH type) and the like can be used, and sodium hydroxide and potassium hydroxide can be preferably used.

It is preferable to carry out the condensation polymerization reaction at a relatively low temperature, that is, at least 50 ° C. or lower, particularly 25 ° C. or lower. The reaction time is not particularly limited, but is usually in the range of 1 minute to 100 hours.

According to the method of the present invention, the polymer intermediate is soluble and can be obtained as a high molecular weight polymer electrolyte having a sulfonium salt in a side chain (polymer sulfonium salt). Further, the obtained polymer intermediate may be modified into a structure in which the sulfonium salt side chain is substituted with a nucleophilic substituent. For example, by reacting an alcohol used as a polymerization solvent, an alkoxy group becomes a side chain and an intermediate soluble in an organic solvent can be obtained. Intermediates are sensitive to heat, light, ultraviolet light, strong bases or acidic conditions, etc., and the elimination of side chains occurs gradually.

A feature of the present invention is that a molded article of any shape can be produced from a polymer intermediate, particularly a solution thereof. Any method is used to obtain a polymer molded product. As for the form, for example, it can be formed into a film, fiber, coating film, or any other form. Particularly useful molding methods are polymeric sulfonium salts, water or alcohol alone, or an organic solvent soluble in water or alcohol,
For example, a method using a mixed solution with acetone or the like, or a solution in which a sulfonium salt side chain is substituted with a nucleophilic substituent in an organic solvent, such as methoxy when R _{1 in the} above general formula (1) is thiophene This is a method using an N, N-dimethylformamide solution of a polymer intermediate in which a group is substituted on a side chain. This is a method in which a film is formed by casting or a fiber is formed by solution spinning, and a solution is applied to a substrate. At this time, it is preferable to use a polymer intermediate solution which is desalted or unreacted by a dialysis treatment, a reprecipitation treatment or the like in advance.

By post-treatment of the polymer intermediate, a three-dimensional conjugated polymer cross-linked with a conjugated system can be produced. The post-treatment of the polymer intermediate referred to here is to remove the sulfonium salt side chain or the side chain substituted by the nucleophilic substituent by applying conditions such as heat, light, ultraviolet light, strong base or acid treatment. And a conjugated structure, but heat treatment is particularly preferred. The treatment of the polymer intermediate is preferably performed in an inert atmosphere.

The inert atmosphere referred to here means an atmosphere that does not cause deterioration such as oxidation of a polymer during processing, and is generally performed using an inert gas such as nitrogen, argon, and helium.
This may be done under vacuum or in an inert medium.

When performing post-treatment of the polymer intermediate by heat, heat treatment at an excessively high temperature results in decomposition of the formed conjugated polymer, and at low temperatures the formation reaction is slow and impractical. 450 ° C, preferably 100 ° C to 380 ° C, is suitable. The processing time can be appropriately selected depending on the processing temperature, but the range of 1 minute to 10 hours is industrially practical.

The conjugated polymer produced in this manner can be subjected to a heat treatment by stretching and orienting a molded product of a polymer intermediate. These stretching orientation treatments can be performed before or simultaneously with the treatment of the polymer intermediate. Orientation can be performed by devising a molding method, for example, by extrusion with high shearing force, etc., but high orientation can be imparted by stretching and heating a polymer intermediate molded product from a polymer intermediate solution. .

If the conjugated polymer obtained in the present invention is reacted (doped) with a known electron donating or electron accepting molecule or atom, conductivity is exhibited.

The conjugated polymer film obtained by the present invention shows excellent mechanical properties of high strength and high elasticity.

<Effects of the Invention> As described above, according to the present invention, it is possible to obtain a three-dimensional polymer cross-linked by a high-molecular-weight conjugated system, and various types of the present invention can be applied to electric and electronic materials. Is provided.

<Examples> The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 1,2,4,5-tetrakis (bromomethyl) benzene and tetrahydrothiophene A solution obtained by dissolving 0.8 g of a tetrafunctional sulfonium salt monomer and 7 g of p-xylylenebis (tetramethylenesulfonium chloride) in 100 ml of ion-exchanged water is cooled to 0-5 ° C. with ice and then nitrogen bubbling is carried out. To replace the inside of the system with nitrogen. To this solution, 61 ml of a 0.35 N sodium hydroxide solution, which was similarly cooled and purged with nitrogen, was added dropwise over about 90 minutes. 0-5 after dropping
When the polymerization was carried out at a temperature of 2 ° C. for 2 hours, a gel-like precipitate was formed. The polymerization solution was neutralized, and the generated precipitate was recovered. This precipitate was soluble in methanol. This solution was cast and dried in a stream of nitrogen to obtain a pale yellow conjugated polymer intermediate film.

This intermediate film (length 2 cm, width 3 cm) was stretched up to 6.5 times in a nitrogen stream using a horizontal tubular furnace, and heated at 370 ° C. for 2 hours to obtain a stretched conjugated polymer film. The infrared dichroism (1520 cm ^-1 ) of this film was 18.6.

When using H ₂ SO ₄ is an electron acceptor compound in the stretched film obtained in Reference Example 1 Example 1 was carried out doping in H ₂ SO ₄ at room temperature by a conventional method, 3.0 × 10 ³ S / cm conductivity.
The conductivity was measured by a four-terminal method.

Example 2 Ion exchange between 0.32 g of a tetrafunctional sulfonium salt monomer obtained by reacting 1,2,4,5-tetrakis (bromomethyl) benzene with tetrahydrothiophene and 7 g of p-xylylenebis (tetramethylenesulfonium chloride) After the solution dissolved in 100 ml of water is ice-cooled to 0 to 5 ° C,
The inside of the system was replaced with nitrogen by nitrogen bubbling. To this solution, 61 ml of a 0.35 N sodium hydroxide solution, which was similarly cooled and purged with nitrogen, was added dropwise over about 90 minutes. After the addition, polymerization was continued for 2 hours at 0 to 5 ° C., and a gel-like precipitate was formed. The polymerization solution was neutralized, a large amount of acetone was added, and the resulting precipitate was collected. This precipitate was soluble in methanol. This solution was cast and dried in a stream of nitrogen to obtain a pale yellow conjugated polymer intermediate film. This intermediate film (length 2 cm, width 3 cm) is stretched to 7.6 times in a nitrogen stream using a horizontal tubular furnace at 370 ° C.
Heat treatment was performed for a time to obtain a stretched conjugated polymer film. The infrared dichroism (1520 cm ^-1 ) of this film was 33.9.

Reference Example 2 When the stretched film obtained in Example 2 was doped with H ₂ SO ₄ as an electron acceptor compound in a conventional manner at room temperature in H ₂ SO ₄ , 6.6 × 10 ³ S / cm conductivity.
The conductivity was measured by a four-terminal method.

Example 3 A solution prepared by dissolving 7 g of p-xylylenebis (tetramethylenesulfonium chloride) in 100 ml of ion-exchanged water was prepared by
After ice cooling to 5 ° C, the inside of the system was replaced with nitrogen by nitrogen bubbling. To this solution, 61 ml of a 0.35 N sodium hydroxide solution, which was similarly cooled and purged with nitrogen, was added dropwise over about 90 minutes. After the addition, polymerization was continued for 2 hours at 0 to 5 ° C., and a gel-like precipitate was formed. 25 ml of methanol was added to the polymerization solution to make a homogeneous solution, and then 1,2,4,5
A solution obtained by reacting tetrakis (bromomethyl) benzene with tetrahydrothiophene and dissolving 0.328 of a tetrafunctional sulfonium salt monomer in 10 ml of ion-exchanged water was added. Subsequently, polymerization was carried out at 0 to 5 ° C for 2 hours. The polymerization solution was neutralized, a large amount of acetone was added, and the resulting precipitate was collected. This precipitate was soluble in methanol. This solution was cast and dried in a stream of nitrogen to obtain a pale yellow conjugated polymer intermediate film. This intermediate film (length 2 cm, width 3 cm) was stretched up to 6.0 times in a nitrogen stream using a horizontal tubular furnace, and heated at 370 ° C. for 2 hours to obtain a stretched conjugated polymer film. The infrared dichroism (1520 cm ^-1 ) of this film was 30.2.

Reference Example 3 The film obtained in Example 3 was added to the electron acceptor compound H _2.
Doping in H ₂ SO ₄ at room temperature using SO ₄ by a conventional method showed an electric conductivity of 5.2 × 10 ³ S / cm. The conductivity was measured by a four-terminal method.

Example 4 Ion-exchanged water was obtained by reacting 1.4 g of a tetrafunctional sulfonium salt monomer obtained by reacting 1,2,4,5-tetrakis (bromomethyl) benzene with tetrahydrothiophene and 7 g of p-xylylenebis (tetramethylene sulfonium chloride). The solution dissolved in 120 ml was ice-cooled to 0 to 5 ° C, and the inside of the system was replaced with nitrogen by bubbling with nitrogen. To this solution, 61 ml of a 0.35 N sodium hydroxide solution, which was similarly cooled and purged with nitrogen, was added dropwise over about 90 minutes. 0-5 ° C after dropping
The polymerization was continued for 2 hours to produce a gel precipitate. The polymerization solution was neutralized, a large amount of acetone was added, and the resulting precipitate was collected. This precipitate was soluble in methanol. This solution was cast and dried in a stream of nitrogen to obtain a pale yellow conjugated polymer intermediate film. This intermediate film in a nitrogen stream, using a horizontal tubular furnace,
Heat treatment was performed at 370 ° C. for 2 hours to obtain a conjugated polymer film.

When using H ₂ SO ₄ is an electron acceptor compound in the stretched film obtained in Reference Example 4 Example 4 was carried out doping in H ₂ SO ₄ at room temperature by a conventional method, 1.6 × 10 ² S / cm conductivity.
The conductivity was measured by a four-terminal method.

Example 5 2.0 g of a tetrafunctional sulfonium salt monomer obtained by reacting 1,2,4,5-tetrakis (bromomethyl) benzene with tetrahydrothiophene and 15 g of 2,5-thienylenebis (methylenedimethylsulfonium bromide) The solution dissolved in 260 ml of deionized water / 260 ml of methanol was
After cooling to ~ -30 ° C, the inside of the system was replaced with nitrogen by nitrogen bubbling. This solution was cooled on ice and purged with nitrogen.
A mixed solution of 21 ml of a prescribed sodium hydroxide solution / 160 ml of methanol was added dropwise over about 40 minutes. After dropping, polymerization was continued at −40 to −30 ° C. for 1.5 hours. After neutralizing the polymerization solution, the solution was dialyzed for 1 day at an ice-cold temperature with a mixed solvent of methanol / water = 1 / 0.15. Next, the resulting precipitate was collected by filtration, washed quickly with methanol, and dissolved in N, N-dimethylformamide (DMF). This was filtered through a Millipore filter to obtain a DMF solution of the conjugated polymer intermediate. The solution was cast and dried in a nitrogen stream to obtain a pale yellow conjugated polymer intermediate film. Next, this film was heat-treated at 250 ° C. for 2 hours in a nitrogen stream to obtain a conjugated polymer film.

Using the I ₂ is an electron acceptor compound in the stretched film obtained in Reference Example 5 Example 5 was subjected to doping in the gas phase at room temperature by a conventional method, the conductivity of 3.5 × 10 ² S / cm showed that. The conductivity was measured by a four-terminal method.

Comparative Example 1 A solution prepared by dissolving 7 g of p-xylylenebis (tetramethylenesulfonium chloride) in 100 ml of ion-exchanged water was used.
After ice cooling to 5 ° C, the inside of the system was replaced with nitrogen by nitrogen bubbling. To this solution, 61 ml of a 0.35 N sodium hydroxide solution, which was similarly cooled and purged with nitrogen, was added dropwise over about 90 minutes. After the addition, polymerization was continued for 2 hours at 0 to 5 ° C., and a gel-like precipitate was formed. Neutralize the polymerization solution,
A large amount of acetone was added, and the resulting precipitate was collected. This precipitate was soluble in methanol. This solution was cast and dried in a stream of nitrogen to obtain a pale yellow conjugated polymer intermediate film. This intermediate film (length 2c
m, width 3 cm) was stretched to 7.8 times in a nitrogen stream using a horizontal tubular furnace, and heated at 370 ° C. for 2 hours to obtain a stretched conjugated polymer film. The infrared dichroism (1520 cm ^-1 ) of this film was 30.0. Using H ₂ SO ₄ as an electron acceptor compound for this stretched film,
Doping in ₂ SO ₄ showed a conductivity of 4.1 × 10 ³ S / cm. The conductivity was measured by a four-terminal method.

Comparative Example 2 A solution of 8.2 g of a tetrafunctional sulfonium salt monomer obtained by reacting 1,2,4,5-tetrakis (bromomethyl) benzene with dimethyl sulfide in 70 ml of ion-exchanged water was heated to 0 to 5 ° C. After ice cooling, the inside of the system was replaced with nitrogen by nitrogen bubbling. To this solution, 75 ml of 0.33 N sodium hydroxide solution, which was similarly cooled and replaced with nitrogen, was added for about 30 minutes.
Dropped over minutes. A yellow precipitate formed during the addition.
After dropping, polymerization was continued at 0 to 5 ° C. for 0.5 hour. The polymerization liquid was neutral. The precipitate was collected but was insoluble. The precipitate was subjected to a heat treatment at 370 ° C. for 1 hour in a horizontal tube furnace in a nitrogen stream, whereby a black powder was obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-159429 (JP, A) JP-A-63-273363 (JP, A) JP-A-64-79223 (JP, A) JP-A 64-64 20234 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08G 61/00-61/12

Claims (1)

(57) [Claims] 1. A general formula ^{_{X 1 - G '+ -CH 2}} -R 1 -CH 2 -G' + X 1 - R 1: -CH = CH- and continuous carbon - group forming a carbon-conjugated system R _2, R _3: a hydrocarbon group having 1 to 20 carbon atoms, R _4: difunctional having 4 to 20 carbon atoms hydrocarbon group X ₁ ^-: bifunctional monomer represented by the counter-ion of the general formula R ₅ CH ₂ —G ″ ⁺ X ₂ ⁻ ) _n R ₅ : a group forming a continuous carbon-carbon conjugated system with —CHCHCH— R ₆ , R ₇ : a hydrocarbon group having 1 to 20 carbon atoms; R ₈ : a bifunctional hydrocarbon group having 4 to 20 carbon atoms; X ₂ ⁻ : a counter ion n: an integer of 3 or more; A method for producing a conjugated polymer, comprising subjecting a conjugated polymer precursor obtained by copolymerizing the above monomer to desulfonium salt treatment in an inert atmosphere.