JPH082946B2 - Method for producing film composed of poly-P-phenylene vinylene substitution product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a carboxyl group nucleus substitution having high conductivity.
It relates to a method for producing a film composed of poly-p-phenylene vinylene. This polymer is useful as a conductive polymer.

<Prior Art> As substitution products of poly-p-phenylene vinylene, substitution products of alkyl groups and alkoxy groups disclosed in JP-A-60-11528 are known.

Further, a substitution product of an alkylene sulfonic acid group, which has been studied from the viewpoint of binding a dopant of a conductive polymer to a molecular chain, is also known (Wudl et al., Proceedings of t
he ACS Division of Polymeric Materials: Science and
Engineering Vol.59,1164-1166,1988).

<Problems to be Solved by the Invention> As described above, various substitution poly-
Most of the substituents of p-phenylene vinylene affect the electronic state and ionic state in the molecule. But,
Poly-p-phenylene vinylene is a substituent effective for functionalization and improvement of conductivity, that is, a substituent having reactivity with a functional molecule and a substituent having strong interaction between substituents. Nothing was known about p-phenylene vinylene.

An object of the present invention is a linear conjugated polymer, which is a carboxyl group nucleus-substituted poly-p capable of utilizing functionalities and hydrogen bonds to improve bonding of functional molecules and intermolecular interaction. -To provide a method for producing a film made of phenylene vinylene.

<Means for Solving the Problems> As a result of diligent studies on the reactive substituents, the present inventors have found that a film made of a high molecular weight poly-p-phenylene vinylene having a carboxyl substituent, which has not been heretofore known. Succeeded in manufacturing.

That is, the present invention has the general formula (2) A: hydrogen or an alkali metal,, m: 1 or 2, X ^-: a counter ion, R ₁ , R ₂ : a hydrocarbon group having 1 to 20 carbon atoms, R ₃ : a bifunctional hydrocarbon group having 4 to 20 carbon atoms, by casting from an aqueous solution of a conjugated polymer intermediate having a repeating unit represented by A film of the general formula (I), which is characterized in that the film is heat-treated at 100 ° C. or higher and 380 ° C. or lower in an inert atmosphere of the obtained film to eliminate the side chain of the sulfonium salt of the intermediate A method for producing a film comprising a poly-p-phenylene vinylene substitution product having a repeating unit represented by A: hydrogen or an alkali metal, m: 1 or 2.

 Hereinafter, the present invention will be described in detail.

A film comprising a poly-p-phenylene vinylene substitution product represented by the general formula (1) is obtained by casting a film from an aqueous solution of the conjugated polymer intermediate of the general formula (2),
It is obtained by subjecting the film to a heat treatment in a specific temperature range to remove the sulfonium salt side chain. When the substituent is an alkali metal salt, it may be synthesized by neutralizing the carboxyl group with an alkali metal hydroxide. The number of substituents is 1 or 2.

To synthesize the conjugated polymer intermediate of the general formula (2), the general formula (3) A and m are the same as in the above formula (2), X ⁻ : counter ion, R ₁ , R ₂ : a hydrocarbon group having 1 to 20 carbon atoms, R ₃ : a bifunctional hydrocarbon group having 4 to 20 carbon atoms, and a carboxyl group-substituted-p-xylylene bissulfonium salt represented by: Are hydrogen or alkali metals such as lithium, sodium and potassium, with hydrogen and sodium being particularly preferred. Examples of R ₁ and R ₂ include hydrocarbon groups having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, 2-ethylhexyl, phenyl, cyclohexyl and benzyl groups. Hydrocarbon group 6 is preferred, especially methyl and ethyl groups. Examples of R ₃ include bifunctional hydrocarbon groups having 4 to 10 carbon atoms such as tetramethylene, pentamethylene and hexamethylene groups, with tetramethylene and hexamethylene groups being particularly preferred.

Pair of sulfonium salt ions X ^- is can be used any of the conventional methods. For example, halogen, hydroxyl group,
Boron tetrafluoride, perchloric acid, carboxylic acid, sulfonate ion and the like can be used, and among them, halogen ion such as chlorine, bromine and iodine is preferable.

The polymer intermediate can be obtained by condensation polymerization of a carboxyl group-substituted-p-xylylenebissulfonium salt with water alone or in a mixed solvent with a water-soluble organic solvent such as alcohols using an alkali. it can. Polymerization is effective in a mixed solvent of water and an alcohol soluble therein, and even more preferably in a water solvent.

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, sodium hydroxide, potassium hydroxide, and hydroxide. Calcium, quaternary ammonium salt hydroxide, sulfonium salt hydroxide, strong basic ion exchange resin (OH type) and the like can be used, but sodium hydroxide and potassium hydroxide are preferably used. In order to obtain a polymeric intermediate rich in molding, it is preferable that the molecular weight is sufficiently large, and at least the degree of polymerization of the polymeric intermediate is 10 or more, preferably 20 to 5000.
At 0, for example, those having a molecular weight that is not dialyzed by dialysis treatment with a dialysis membrane having a molecular weight cut off of 3500 are effectively used.

It is preferable to carry out the condensation polymerization reaction at a relatively low temperature, that is, at a temperature of 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 200 hours.

According to the method of the present invention, the polymer intermediate can be obtained as a high molecular weight polymer electrolyte having a sulfonium salt in the side chain (polymer sulfonium salt).
It is sensitive to heat, light, ultraviolet rays, strong basic conditions, etc., and gradually desulfonium chloride occurs. Since this polymer intermediate gives a solution having a relatively low viscosity, it is preferable from the viewpoint of molding. A feature of the present invention is to obtain a film by casting using an aqueous solution of a high molecular weight sulfonium salt. At this time, it is preferable to use a polymer intermediate solution from which desalted or unreacted substances have been removed by dialysis or reprecipitation.

Carboxyl group nucleus substitution by post-treatment of polymer intermediate-
Poly-p-phenylene vinylene can be produced. As a post-treatment of the polymer intermediate here, heat treatment is performed in an inert atmosphere.

The inert atmosphere referred to here is an atmosphere that does not cause deterioration of the polymer during the treatment, and is generally performed using an inert gas such as nitrogen, argon, or helium, but under a vacuum or in an inert medium. You may go.

When the post-treatment of the polymer intermediate is carried out by heat, heat treatment at an excessively high heat produces a carboxyl group nucleus-substituted poly-
Since the decomposition of p-phenylene vinylene is caused, and the formation reaction is slow and impractical at low temperature, the treatment temperature is 100 to 380 ° C.
Is. The processing time can be appropriately selected depending on the processing temperature, but a range of 1 minute to 10 hours is practical in the factory.

The carboxyl group nucleus-substituted poly-p-phenylene vinylene thus produced contains carboxyl-P-phenylene vinylene as a main structural unit. According to the production method of the present invention, it is possible to prepare a carboxyl group nucleus-substituted poly-p-phenylene vinylene having only a repeating unit of a conjugated system of carboxyl-p-phenylene vinylene, and a non-conjugated carboxyl-p. It is also possible to make a polymer containing a phenylene ethylene skeleton as a part of its constitutional unit. That is, the carboxyl group still in an incomplete elimination state in the polymer after the insufficient elimination treatment is carried out.
The presence of a structural unit having a p-phenylene ethylene skeleton is observed by infrared absorption spectrum and the like. In this case, a highly flexible carboxyl group nucleus substitution-poly-
p-Phenylene vinylene can be produced. The ratio of the carboxyl-p-phenylene ethylene unit to the carboxyl-p-phenylene ethylene unit can be changed by arbitrarily adjusting the production conditions according to the purpose of use. The ratio of the latter to the former is preferably 1 or less, and more preferably 1/20 or less for the purpose of a conductive polymer material or the like.

Further, the molded product of the polymer intermediate may be stretched and oriented and heat-treated. These stretch orientation treatments can be performed before or simultaneously with the treatment of the polymer intermediate. The orientation can be achieved by devising the molding method, for example, extrusion by high shearing force, but high orientation can be imparted by subjecting the polymer intermediate molded product from the polymer intermediate solution to stretching heat treatment. .

When the film comprising the poly-p-phenylene vinylene substitution product obtained in the present invention is reacted (doped) with an electron-donating or electron-accepting molecule or atom, conductivity is exhibited.

<Effects of the Invention> As described above, according to the present invention, it is possible to obtain a film composed of a high-molecular-weight carboxyl group nucleus-substituted-poly-p-phenylenevinylene, and the present invention can be applied to electric and electronic materials. Carboxyl group substitution
A film comprising poly-p-phenylene vinylene 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 9.7 g of 3-carboxyl-p-xylylene bis (teslamethylene sulfonium bromide) was added to 150 ml of ion-exchanged water.
The solution dissolved in was cooled with ice to 0 to 5 ° C., and then the system was replaced with nitrogen by nitrogen bubbling. To this solution, 100 ml of a 0.4 N sodium hydroxide aqueous solution which had been similarly cooled and purged with nitrogen was added dropwise over about 30 minutes. After the dropping, polymerization was continued at 0 to 10 ° C for 30 hours. Next, the polymerization solution was dialyzed in ion-exchanged water using a dialysis membrane under ice cooling for 2 days,
A purified carboxyl group nucleus-substituted poly-p-phenylene vinylene intermediate aqueous solution was obtained. It was cast from this aqueous solution and dried in a nitrogen stream to obtain a slightly yellow intermediate film. As a result of analysis of the evolved gas accompanying the heat treatment of the cast film, only the signal related to tetradrothiophene generated by the elimination of the side chain of the sulfonium salt was detected. Next, the change in infrared absorption spectrum when the cast film was heat-treated at 350 ° C. was observed. At 350 ° C, absorption attributed to transvinylene around 960 cm ^-1 was clearly observed. Further, the carboxyl group near 1760 cm ^-1, trisubstituted benzene ring in the vicinity of 833cm ^-1, the absorption attributable to each were observed. From the above, the structure of the carboxyl group-substituted-poly-p-phenylene vinylene was confirmed.

Reference Example 1 In Example 1, SO ₃ as an electron acceptor compound was used for carboxyl group nucleus-substituted-poly-p-phenylene vinylene obtained by heat treatment at 350 ° C., and doping from a gas phase was performed at room temperature by a conventional method. The conductivity of 1.4 × 10 ⁻³ S / cm was shown. The conductivity was measured by the four-terminal method.

Example 2 The polymer intermediate film obtained in Example 1 was heat-stretched at 350 ° C. under nitrogen flow to obtain a 1.5-fold stretched carboxyl group nucleus-substituted poly-p-phenylene vinylene stretched film. Obtained. This film showed infrared dichroism and was found to be oriented.

Example 3 The polymer intermediate film obtained in Example 1 was subjected to a standing heat treatment in a horizontal tubular furnace at 250 ° C. for 60 minutes under a nitrogen atmosphere, and a yellow non-conjugated carboxyl-p-phenylene ethylene. A polymer carboxyl group nucleus-substituted poly-p-phenylene vinylene film containing a skeleton as a constituent unit was obtained. This structure was confirmed by infrared absorption spectrum.

Reference Example 2 Carboxyl group-substituted poly-p-phenylene vinylene film obtained in Example 3 was added to the electron acceptor compound I ₂
Was used to perform doping from the gas phase at room temperature by a conventional method, and it showed an electric conductivity of 3.3 × 10 ⁻³ S / cm. The conductivity was measured by the four-terminal method.

Claims (1)

[Claims] 1. A general formula A: hydrogen or an alkali metal,, m: 1 or 2, X ^-: a counter ion, R ₁ , R ₂ : a hydrocarbon group having 1 to 20 carbon atoms, R ₃ : a bifunctional hydrocarbon group having 4 to 20 carbon atoms, by casting from an aqueous solution of a conjugated polymer intermediate having a repeating unit represented by A film is obtained, which is heat-treated at 100 ° C. or higher and 380 ° C. or lower in an inert atmosphere of the obtained film to eliminate the sulfonium salt side chain of the intermediate, the general formula: A: A method for producing a film comprising a poly-p-phenylene vinylene substituent having a repeating unit represented by hydrogen or an alkali metal m: 1 or 2.