JPH0433290B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a method for producing a stretched polythienylene vinylene body. This stretched molded product is useful as a material for conductive polymers. <Prior art> The poly-2,5-thienylene vinylene of the present invention is known as a linear conjugated polymer, and is synthesized by the Wittig reaction method by reacting a diphosphonium salt with a dialdehyde. It is known that [Macromol.Chem.] Vol. 182, p. 3419 (1981), Macromol.Chem.
Volume 131, page 15 (1970)]. Furthermore, the conductivity of the polymer has been measured, and it was known that it exhibits insulating or semiconducting properties of at most 10 ^-8 S/cm or less. Further, a conductive composition in which the above-mentioned powder polymer is doped with an electron acceptor or an electron donor is also proposed in JP-A-59-11327. <Problems to be Solved by the Invention> However, the previously known polythienylene vinylene described above is produced in powder form, and the polymers except for low polymers are insoluble and infusible, and as it is, it forms into a film or fiber. It is virtually impossible to mold the powder into powder, and no useful molded product has been obtained even by using special powder molding methods. Furthermore, the conductivity of the above conductive composition is up to 10 ^-3 S/cm.
This is too low for practical use, and the shape is powder. The object of the present invention is to be able to obtain polythienylene vinylene with a higher molecular weight than the conventional powdered polythienylene vinylene.
Another object of the present invention is to provide a method for producing a stretched molded article having an arbitrary shape. <Means for solving the problems> The present invention has the following general formula [1] R ₁ , R ₂ : Hydrocarbon group having 1 to 10 carbon atoms A ^- : Desulfonium is removed after the polymer intermediate obtained by condensing the sulfonium salt represented by the counter ion with an alkali is stretched or oriented twice or more. It is an object of the present invention to provide a method for producing a polythienylene vinylene stretched molded article, characterized in that a salt treatment is carried out, or a desulfonium salt treatment is carried out at the same time as twice or more stretching orientation. The polythienylene vinylene stretched molded product obtained in the present invention can be made into a highly conductive stretched molded product by adding a dopant. As a result of extensive research into obtaining a conductive composition that can be formed into any desired form and has high conductivity, the present invention has revealed that this object can be achieved by a method that involves a processable polymer intermediate. This is what I found. The present invention will be explained in detail below. The monomer used in this reaction is a 2,5-thienylene dimethylene bissulfonium salt shown in general formula [1], and R ₁ and R ₂ are hydrocarbon groups having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, Isopropyl, n-butyl, 2-ethylhexyl, dodecyl, octadecyl, phenyl, cyclohexyl,
Examples include a benzyl group, but a hydrocarbon group having 1 to 6 carbon atoms, particularly a methyl and an ethyl group, are preferred. Any counter ion A ^- of the sulfonium salt can be used in a conventional manner. For example, halogen, hydroxyl group, boron tetrafluoride, perchloric acid, carboxylic acid, sulfonic acid ion, etc. can be used,
Among these, halogens such as chlorine, bromine, and iodine and hydroxyl ions are preferred. The polymer intermediate can be obtained by condensation polymerization of 2,5-thienylene dimethylene bissulfonium salt using an alkali in water alone or in a mixed solvent with a water-soluble organic solvent such as an alcohol. It is effective to polymerize preferably in a mixed solvent of water and an organic solvent soluble therein, more preferably in a mixed solvent of water and alcohols. The alkaline solution used for condensation polymerization is preferably a strongly basic solvent with a pH of 11 or higher in water or a mixed solvent of alcohol and water, and includes sodium hydroxide, potassium hydroxide, calcium hydroxide, quaternary
Ammonium salt hydroxides, sulfonium salt hydroxides, strongly basic ion exchange resins (OH type), etc. can be used, and sodium hydroxide, potassium hydroxide, and strongly basic ion exchange resins are preferably used. In order to obtain a polymer intermediate with excellent formability into a stretched molded product, it is preferable that the molecular weight is sufficiently large, and the degree of polymerization of the polymer intermediate is at least 5 to 50,000, for example, a dialysis membrane with a molecular cutoff of 3,500 or more. More preferred are those having a molecular weight that will not be dialyzed by dialysis treatment. According to the method of the present invention, the polymer intermediate can be obtained as a high molecular weight polymer electrolyte (polymer sulfonium salt) having a sulfonium salt in its side chain. It is sensitive to basic conditions, etc., and desulfonium saltation occurs gradually, and it tends to form a polymeric intermediate having a partially conjugated structure, which may result in heterogeneity. Therefore, the condensation polymerization reaction is preferably carried out at a relatively low temperature, that is, at least 50°C or lower, particularly 25°C or lower, and more preferably 0°C or lower. The reaction time is not particularly limited, but is usually in the range of 1 minute to 50 hours. The feature of the present invention is to produce a stretched molded article having an arbitrary shape of twice or more from a polymer intermediate, especially a solution thereof. Any method can be used to obtain the polymer stretched molded product. Regarding its form, it can be shaped into, for example, a film, fiber, coating film, foam, or any other stretched molded product. A particularly useful molding method is a method using an aqueous solution of a polymeric sulfonium salt or a solution in another medium such as tetrahydrofuran, followed by forming a film by casting or forming a fiber by solution spinning, or applying the solution to a substrate. At this time, it is preferable to use a polymer sulfonium salt solution that has been desalted or unreacted substances removed by dialysis treatment or reprecipitation treatment. Polythienylene vinylene can be produced by desulfonium salt treatment of a polymeric sulfonium salt. Desulfonium salt treatment can be carried out by applying conditions such as heat, light, ultraviolet rays, strong base treatment, etc., but heat treatment is preferable. Furthermore, in order to obtain a highly conductive composition, it is important to perform the desulfonium salt treatment of the polymer intermediate in an inert atmosphere. The inert atmosphere here refers to an atmosphere that does not cause deterioration of the polymer during processing, and is generally carried out using an inert gas such as nitrogen, argon, helium, etc., but under vacuum or in an inert liquid medium. You may do this. When desulfonium salt treatment is carried out by heat, heat treatment at excessively high temperatures will result in decomposition of the polythienylene vinylene produced, and the production reaction is slow and impractical at low temperatures, so the treatment temperature is usually 0°C to 400°C,
Preferably 50°C to 300°C, more preferably 100°C
~250℃ is suitable. In addition, the processing time can be selected as appropriate depending on the processing temperature, but from 1 minute to
A range of 10 hours is industrially practical. The stretched molded product of the present invention can be obtained by stretching and orienting a molded product of a polymer intermediate twice or more and heat-treating the molded product. The stretching or orientation treatment with a stretching strength of 2 times or more can be performed before or simultaneously with the desulfonium salt treatment. High orientation can be imparted by obtaining a polymer intermediate molded product from a polymer sulfonium salt solution and then subjecting the molded product to a stretching heat treatment at a stretching ratio of 2 times or more. The extent of these stretching orientations can be confirmed by the appearance of infrared dichroism in the polarized infrared spectrum. In this way, it is possible to obtain polythienylene vinylene that has been stretched twice or more, and stretching orientation is an extremely effective operation for obtaining high conductivity. The polythienylene vinylene produced in this way contains 2,5-thienylene vinylene units as the main repeating unit. According to the method of the invention,
In addition to making polythienylene vinylene having only conjugated repeating units of 2,5-thienylene vinylene, it is also possible to create a polymer containing a non-conjugated 2,5-thienylene ethylene skeleton as a part of its constituent units. It is also possible to make one. In other words, it has been observed by infrared absorption spectroscopy that there are still structural units having a 2,5-thienylene ethylene skeleton in an incompletely desorbed state in the polymer after insufficient desorption treatment. Ru. In this case, highly flexible polythienylene ethylene vinylene can be produced. Note that the ratio of 2,5-thienylene ethylene units to 2,5-thienylene vinylene units can be changed by arbitrarily devising production conditions depending on the purpose of use. The polythienylene vinylene in the present invention does not necessarily have to have only complete conjugated repeating units. 2,5- which is still in an incomplete state of elimination
We have discovered the surprising fact that even polythienylene vinylene containing a thienylene ethylene skeleton as a constituent unit of its main chain can be endowed with conductivity through subsequent doping. In this case, there is an advantage that a highly flexible conductive composition can be obtained. Usually, in order to obtain a highly conductive composition, 2,5-
The ratio of 2,5-thienylene ethylene units to 1 thienylene vinylene unit is preferably 1 or less,
More preferably it is 1/20 or less. Next, the polythienylene vinylene stretched molded product obtained by the desulfonium salt treatment in the present invention can be made into a highly conductive composition by acting with an electron acceptor or an electron donor (referred to as a dopant). As the dopant, known conductive polymer compounds such as polyacetylene doped or compounds that have been found to have an effect of improving conductivity by forming an intercalation compound of graphite are effectively used. The composition can be obtained by any method, but
Doping is preferably carried out by conventionally known techniques such as chemical doping, electrolytic doping, optical doping, and ion implantation. Specifically, as electron acceptors, halogen compounds: fluorine, chlorine, bromine, iodine, iodine chloride, iodine trichloride, iodine bromide Lewis acids: phosphorus pentafluoride, arsenic pentafluoride, antimony pentafluoride , boron trifluoride, boron trichloride, boron tribromide, sulfur trioxide Protonic acids: hydrogen fluoride, hydrogen chloride, nitric acid, sulfuric acid, perchloric acid, sulfonic fluoride, sulfonic chloride, methanesulfone trifluoride Acid transition metal chlorides: titanium tetrachloride, zirconium tetrachloride, hafnium tetrachloride, niobium pentachloride, tantalum pentachloride, molybdenum pentachloride,
Tungsten hexachloride, iron trichloride organic compounds: tetracyanoethylene, tetracyanoquinodimethane, chloranil, dichlorodicyanobenzoquinone Alkali metals as electron donors: lithium, sodium, potassium, rubidium, cesium Quaternary ammonium salts : Examples include tetraalkylammonium ions. The preferred content of the doping reagent varies depending on the type of doping reagent, but can generally be arbitrarily changed depending on doping conditions such as doping time and doping reagent concentration. Generally preferred content is 0.01 to 0.01 molar number of dopant to polythienylene vinylene repeating unit.
The amount is 2.0 moles, and if the number of moles is small, high conductivity will not be achieved, and if the number of moles is too large, the conductivity will tend to be saturated, which is not economical. Among these doping agents, dopants that do not react with the generated conjugated double bond and the thienylene ring are preferred because they provide a highly conductive composition. Particularly effective doping agents include sulfur trioxide or iodine, which is known as a dopant with weak oxidizing power. In the stretched molded product obtained according to the present invention, when iodine is used as a dopant with particularly weak oxidizing power, a highly oriented molded product composition has a 200 S/cm
As described above, high conductivity of 500 S/cm or more can be provided in some cases. At this time, the uniaxially stretched composition exhibits electrical anisotropy, and an anisotropy of 5 times or more can be provided in the stretching direction and the direction perpendicular to the stretching direction. In order to provide high conductivity, it is highly preferable to perform the desulfonium salt treatment and the composition formation operation with a doping agent under an inert atmosphere. <Effects of the Invention> As explained above, according to the present invention, it is possible to obtain a stretched molded product of polythienylene vinylene, which is a conjugated polymer, having various shapes that are stretched and oriented twice or more. Since the stretched molded product is doped to provide a highly conductive composition, it can be applied to various electrical and electronic materials utilizing conductivity. <Examples> The present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples in any way. Comparative Example 1 Ion exchange in which 3.9 g of 2,5-thienylene-bis(methylenedimethylsulfonium bromide) was dissolved in 50 ml of a mixed solvent of ion-exchanged water and methanol (volume ratio 1:1), and then 0.4 g of NaOH was dissolved. Water-methanol mixed solution (volume ratio 1:4) 50
ml over 30 minutes at -30°C, and after dropping at -30°C for 30 minutes.
Stirring was continued for a minute. After the reaction, it was neutralized using a 0.77N HBr aqueous solution. This reaction was carried out using a dialysis membrane (Cerotube, molecular weight fraction 8000, manufactured by Union Carbide) at −30%
Dialysis treatment was performed for 1 day at °C against a water-methanol mixed solvent (1:1). Concentrate the dialysate under reduced pressure,
Precipitate a polymer (polymer sulfonium salt),
The resulting precipitate was separated into solid and liquid. This precipitate H ¹ −NMR
When the spectrum was measured using deuterium-substituted dimethyl sulfoxide as a solvent, the spectrum changed significantly over time. The initial spectrum is 6.7ppm,
Protons were observed at a ratio of 2:1:8 near 4.5 ppm and 3.2 ppm, respectively, indicating the structure of a polymeric sulfonium salt. The resulting precipitate was dissolved in tetrahydrofuran at room temperature, cast, and dried at room temperature under a nitrogen stream. A yellow polymer intermediate film with a thickness of 10 μm was obtained. This film (length 5 cm, width 3 cm) was subjected to static heat treatment in a horizontal tubular furnace at 250°C for 30 minutes under a nitrogen atmosphere, and poly-2, which had a metallic luster,
A 5-thienylene vinylene film was obtained. This structure has been identified by elemental analysis.

[Table] and the characteristic absorption of the infrared absorption spectrum
This was confirmed because the characteristic absorption matched that of the specimen obtained by the Witting method. Furthermore, when this film was doped with iodine, which is an electron acceptor compound, in the gas phase at room temperature by a conventional method, it showed an electrical conductivity of 151 S/cm in 6 hours. The electrical conductivity was measured using the four-terminal method. Comparative Example 2 Using the poly-2,5-thienylene vinylene film obtained in Comparative Example 1 as an electrolyte, 0.5 N LiClO ₄ −
When electrolytic doping was performed using a propylene carbonate solution, the resulting film had a glossy black color and an electrical conductivity of 73 S/cm. Comparative Example 3 When the polyheteroarylene vinylene film obtained in Comparative Example 1 was doped with sulfur trioxide using 30% oleum as a source, the conductivity was 33 S/cm. Example 1 The precipitate obtained by the method described in Comparative Example 1 was
It was a 2,5-thienylene vinylene polymer intermediate, and was immediately dissolved in tetrahydrofuran, and this solution was cast on a polyethylene film and dried in a nitrogen stream to obtain a cast film. This film was stretched three times from room temperature to 100°C and heat treated at 100°C for 2 hours to obtain a stretched poly-2,5-thienylene vinylene film. This film exhibits infrared dichroism,
It was found that it was oriented. This film showed a high electrical conductivity of 553 S/cm due to iodine doping. Furthermore, when the anisotropy of the conductivity was measured by the Montgomery method, an anisotropy of 7 or more was observed, and an improvement in the conductivity was observed in the stretching direction. Example 2 After dissolving 4.3 g of 2,5-thienylene-bis(methylenedimethylsulfonium bromide) in 50 ml of a mixed solvent of ion-exchanged water and methanol, -30
Cooled to ℃. Next, a strongly basic ion exchange resin (Amberlite IRA-401,
(manufactured by Rohm & Haas) was gradually added over 10 minutes, and stirring was continued at -30°C for 50 minutes. After the reaction, the filtrate was dialyzed against a water-methanol mixed solvent at -30°C for one day using a dialysis membrane (Cerotube, molecular weight fraction 3500, manufactured by Union Carbide). Cast this solution at 30°C.
It was dried under reduced pressure for 24 hours. The obtained polymeric sulfonium salt film was heated and stretched to 200° C. under nitrogen flow to obtain a poly-2,5-thienylene vinylene stretched film that had been stretched twice. Next, doping with iodine was performed using a conventional method, and the conductivity was measured, and the conductivity was 287 S/cm. Example 3 The polymer sulfonium salt film obtained by the method described in Example 2 was heated and stretched at up to 200°C under nitrogen flow to produce poly-2,5-
A thienylene vinylene stretched film was obtained. This film showed infrared dichroism by polarized infrared absorption spectroscopy, and was found to be oriented.

Claims (1)

[Claims] 1. General formula [] R ₁ , R ₂ : Hydrocarbon group having 1 to 10 carbon atoms A ^- : Condensation polymerization of a sulfonium salt represented by a counter ion with an alkali, and then stretching or orientation of the obtained polymer intermediate twice or more. Desulfonium salt treatment or 2
A method for producing a polythienylene vinylene stretched molded article, characterized in that a desulfonium salt treatment is carried out at the same time as stretching and orientation at least twice as long. 2. The manufacturing method according to claim 1, wherein the stretched polythienylene vinylene molded product is a film, fiber, foam, or coated film-like molded product.