Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/04—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of carbon-silicon compounds, carbon or silicon
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
  • H01B1/12—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances organic substances
  • H01B1/124—Intrinsically conductive polymers
  • H01B1/127—Intrinsically conductive polymers comprising five-membered aromatic rings in the main chain, e.g. polypyrroles, polythiophenes

Definitions

• the present invention relates to a process for the preparation of an electroconductive organic polymer in the form of a powder which may contain mineral or organic fillers, this powder being compactable under pressure and moldable in the form of electroconductive articles.
• This polymer is obtained by chemical oxidation of one or more pentacyclic hetero-compounds such as thiophene, selenophene, furan, pyrrole, thiazole, oxazole, pyrazole, etc. in the presence of a doping agent .
• the powders thus obtained have a conductivity varying between 10 -2 and 50 S / cm, that is to say a resistivity of 100 - 2x10 -2 Ohm. cm.
• Document GB-A-2,133,022 describes the production of electroconductive polymers with a negative temperature coefficient by treatment of dimethylpyrroies with oxidizing salts such as perchlorate or ferric chloride in aqueous medium or with chlorine gas in acetonitrile medium.
• oxidizing salts such as perchlorate or ferric chloride in aqueous medium or with chlorine gas in acetonitrile medium.
• the polymers thus obtained have a low conductivity (resistivity greater than 10 Ohm. Cm).
• electroconductive polymers in the form of films or in the form of products for impregnating porous materials has also been disclosed.
• document DE-A-33 21 281 mentions the impregnation of insulating materials such as cellulose fibers, papers, porcelain, epoxy resins, etc. with an aqueous solution of a salt of a metal of degree variable oxidation, this metal being at a high oxidation level, in particular FeCl 3 , La (SO 4 ) 2 , K 3 Fe (CN) 6 , CrO 3 , preferably in the presence of an acid. then the addition in gaseous or liquid form of a pyrrolic compound in an alkolic solution or in a nitrile.
• the resistivity of the products obtained is not, however, less than 65 Ohm. cm (see example 1).
• the halides and other salts of mineral and organic acids of metals having the character of Lewis acids in an oxidation state of a higher level and capable of passing, by reaction with an aromatic heterocycle, to a level of internal oxidation by polymerizing oxidation of said heterocycle, and, simultaneously, of forming doping anions of the polymer thus obtained.
• Lewis acids the following bodies may be mentioned: FeCl 3 , CuCl 2 , BiCl 5 , AsCl 5 , SbCl 5 , SbF 5 , MnCl 3 and others.
• salts having only a weak character of a Lewis acid such as, for example, Fe 2 (SO 4 ) 3 and Fe (NO 3 ) 3 may also be suitable.
• the principle of the reaction according to the invention can be illustrated by the following diagram relating to the reaction of pyrrole (PYR) with FeCl 3 , it being understood that similar criteria are applicable to the other cases encompassed by the invention: n [xPYR + (2x + 2) FeCl 3 ] -> [(PYR) -FeCl 4 ] + n (2x + 1) FeCl 2 + 2nxHCl with x being between 2 and 12.
• the polymer obtained has a charge + for x pyrrole groups; the value of x being between 2 and 12 and preferably 3 and 10.
• the important factor, underlined by this diagram, is however the fact that the salt or the Lewis acid used functions both as an oxidative polymerization agent pyrrole and as a doping agent which makes it possible to achieve relatively high conductivities without the addition of additional dopant.
• solvents which can be used in the present process there may be mentioned solvents with an ether function such as ethyl, propyl, butyl ethers, etc., "glymes", dioxane, THF ', esters such as acetate and propionate d ethyl, nitromethane, nitrobenzene, chlorinated solvents such as CCl 4 , chlorobenzene, ethylene or methylene chloride, etc. From the practical point of view, the implementation of the process of the invention is very simple.
• a solution of Lewis acid in the chosen organic solvent is prepared and, on the other hand, a solution of pyrross or another heterocycle in this solvent or another solvent and the procedure is carried out. mixing of the two solutions at ordinary temperature or with cooling to moderate the reaction when it is lively. It is also possible to add the heterocystic compound when it is liquid undiluted by a solvent.
• relative amounts of reagents are preferably used in accordance with the stoichiometry of the reaction; for example, in the reaction schematized above, yields close to the theory will be obtained by using 3 moles of FeCl 3 per mole of pyrross; however, there is no need to strictly observe these conditions and a similar polymer (albeit with a lower yield) will be obtained using, for example, 1 mole of FeCl 3 per mole of pyrrole.
• the precipitation of the desired product is rapidly observed, in the form of a somewhat fibrous pulverulent mass.
• This mass can be collected by filtration and spinning and dried by the usual means.
• the mass is then compacted in an appropriate form and molded according to the shape of the desired object.
• the present electroconductive polymer can be used. to obtain, in the presence of an inorganic or organic pulverulent filler, a pulverulent substance making it possible to manufacture, by the usual methods of compacting and pressure molding or by sintering, compact electroactive articles.
• electroconductive materials capable of being subjected to reversible electro-oxidation-reduction processes involving a variation in the rate of electrical charge (doping) without the participation of metals or metal ions.
• electroconductive materials capable of being subjected to reversible electro-oxidation-reduction processes involving a variation in the rate of electrical charge (doping) without the participation of metals or metal ions.
• polyacetyethylene As an example of such a known material, mention may be made of polyacetyethylene. This polymer is normally a conductive but, by oxidizing or reducing doping, its conductivity can be varied by a factor of the order of 10 12 (see Chemical & Engineering news, January 26, 1981, pages 39-40). such a polymer can be used in particular for the manufacture of accumulators and plastic batteries (see Research, No. 126, October 1981, vol.
• electroconductive powder thus obtained from the electroconductive polymer of the invention and a filler lends itself to all the usual applications involving the use of metallic powders such as electroconductive paints, electroconductive articles in the electrical industry, electrodes in the chemical industry, etc.
• pulverulent filler it is preferred to use carbon black or mineral particles.
• carbon black particles it is possible to use the various types of carbon black available on the market and whose dimensions are of the order of 0.001 to 1 micrometer with a specific surface of 1 mg to 100 mg / m 2 .
• Such carbon blacks are described in document EP-A-98,338.
• mineral particles all fine powder mineral materials can be used such as, for example, those containing silica, alumina or other metal oxides.
• submicron particles such as precipitated or pyrogenic silica are used, such dimensional requirements however not being critical and can be overridden if desired.
• a description of such mineral materials can be found in document EP-A-69,133.
• Other silicate particles such as talc, bentonite, vollastonite, montmorillonite, etc. may also be suitable.
• the amount by weight of electrically conductive polymer relative to the particulate substance in the present powder is preferably between approximately 10 and 100% depending on the properties desired.
• the thickness of the polymer layer which is deposited on the particles during the polymerization can be of the order of a few Angstroms to several micrometers.
• the resistivity of the powder (measured on an article obtained by pressing) generally varies between 10,000 and 10 -2 Ohm. cm depending on the rate of fixation of the electroconductive polymer, and according to the method of preparation.
• the present pulverulent substance it is possible to proceed in various ways including the simultaneous bringing into contact of the particulate charge, the polymerization reagent and the monomer to be polymerized, or the impregnation of the charge with said reagent and, subsequently, the setting in the presence of the charge thus treated with said monomer in liquid (solution) or vapor phase.
• the procedure is, for example, in organic solution using one of the aforementioned reagents simultaneously playing the role of polymerization catalyst and dopant, in particular FeCl 3 .
• the present powder is subjected, in a mold, to a pressure sufficient to promote the adhesion between them of the electroconductive particles, this operation being able to take place, according to cases, in the presence or absence of a usual binder.
• this filler can be dispersed in a solution of 1 in. iymer or in a liquid monomer and then proceed to the polymerization of this monomer. It will be noted that one of the significant advantages of the present powder is its excellent compatibility (good wettability) with most organic polymers, which clearly distinguishes it from the electroconductive powders of the prior art.
• the electrical volume conductivity measured on a pellet obtained by compacting under a pressure of 15 t / cm 2 is 28 Ohm -1 cm -1 , that is to say 3.5 x 10 -2 Ohm. cm.
• Example 3 Comparative example in an aqueous medium
• the volume electrical conductivity, measured on a pellet obtained by compacting under a pressure of 15 t / cm 2 is 2.10hm -1 cm-1, ie a factor of 10 less than the sample obtained in an anhydrous medium (example 1) .
• Example 2 The procedure is as in Example 1 but using 22.43 g (0.075 mole) of SbCl 5 in 150 ml of CCI 4 . The precipitate is washed with CCI 4 and dried under vacuum. 10.8 g of powder are obtained, the volume conductivity of which after compacting is 3.6 ⁇ 10 ⁇ 3 Ohm ⁇ 1 cm ⁇ 1 .
• Example 2 The procedure is as in Example 1 but using 16.25 g (0.075 mole) of SbF 5 in 150 ml of CCI 4 . The precipitate is washed with CCI 4 and dried under vacuum. 12.6 g of powder are obtained, the volume conductivity of which after compaction is 0.28 Ohm -1 cm -1 .
• the carbon black dispersion thus obtained was treated with 16.22 g of anhydrous FeCl 3 , then with 3.35 g of pyrrole. After a few hours of stirring, the dispersion was filtered off, washed and dried; yield 5.12 g.
• the volume conductivity of the black powder thus obtained was 13.27 Siemens / cm.
• Example 11 The procedure was as in Example 11 but using 10 g of silica of various types and varying, on the one hand, the amount of FeCl 3 adsorbed on the silica and, on the other hand, the contact time in vapor phase with pyrrole.
• Example 11 The procedure was as in Example 11, but with 10 g of various fillers (aluminum oxide and rutile are DEGUSSA products), variable amounts of FeCl 3 and different contact times

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• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Polyoxymethylene Polymers And Polymers With Carbon-To-Carbon Bonds (AREA)

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• 1986
  • 1986-09-01 EP EP19860905179 patent/EP0236367B1/de not_active Expired - Lifetime
  • 1986-09-01 DE DE8686905179T patent/DE3673155D1/de not_active Expired - Lifetime
  • 1986-09-01 WO PCT/CH1986/000123 patent/WO1987001504A1/fr not_active Ceased

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