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
  • H01B1/06—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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G61/00—Macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain of the macromolecule
  • C08G61/12—Macromolecular compounds containing atoms other than carbon in the main chain of the macromolecule
  • C08G61/122—Macromolecular compounds containing atoms other than carbon in the main chain of the macromolecule derived from five- or six-membered heterocyclic compounds, other than imides

Definitions

• the invention relates to a process for the preparation of a polymer composition containing an electrically conductive polymer which involves polymerisation of poly erisable monomer units to yield an electrically conductive polymer in a reaction mixture containing a pH buffer.
• polymerisation must, according to Rapi, take place in a reaction mixture that is pH buffered, in such a manner that the pH is higher than 1 and lower than 7. To this end a buffer is added to the reaction mixture. This results in a significant improvement of the electrically conducting properties of the electrically conducting polymer that is obtained.
• precipitate thus formed is not suitable for thermoplastic processing and is not or hardly capable of being shaped into a coherent moulding compound.
• This is achieved with the process according to the invention in that the polymerisable monomer units are obtained through in-situ activation of precursor monomers.
• the process according to the invention it is possible to use simple processing steps to shape moulding compounds and manufacture products that contain electrically conducting polymers. Premature polymerisation is prevented, polymerisation taking place at a point of time of one's own choice.
• the precursor monomers are given the desired shape, after which they can at any given moment be subjected to in situ activation to yield polymerisable monomeric units.
• the activated polymerisable monomeric units are subsequently polymerised to yield an electrically conducting polymer.
• a precursor monomer is understood to be a molecule which as such cannot polymerise under the prevailing process conditions, not even when a catalyst is present. After a simple conversion step, however, this molecule is converted into a polymerisable monomer unit.
• This conversion step may comprise removal of a blocking group that screens off one or more reactive sites. It is also possible to remove an electron-attracting group which raises the oxidation potential of the molecule and which thus prevents polymerisation.
• an intramolecular reaction takes place, for example a retro-
• Any precursor monomer which after activation becomes a polymerisable monomeric unit from which an electrically conducting polymer can be formed is suitable for use in the process according to the invention.
• suitable precursor monomers are molecules having a structure according to formula (I), where
• X is -N-, -S- or -0-;
• H Rl is hydrogen, -C(0)OH, -C(0)C(0)0H, -C(0)H, -S0 3 H, -I or
• R2 is hydrogen, an alkyl group (with 1-10 carbon atoms),
• R3 is hydrogen, an alkyl group (with 1-10 carbon atoms), -C(0)OH, or a halogen;
• R4 is hydrogen, -C(0)OH, -C(0)C(0)0H, -C(0)H, -S0 3 H, -I or
• Rl and R4 are not simultaneously hydrogen, and that R2 and R3 can both form part of a closed ring structure.
• Rl and R4 positions are identical or different.
• the groups R2 and R3 can be identical or different.
• XI and X2 are identical or different and are -N-, -S- or -0; I
• R4 Rl and R2 are identical or different and are hydrogen or an alkyl group with 1-10 carbon atoms; R4 is hydrogen or an alkyl, aryl or alkoxy group.
• the precursor monomers according to formula (II) can, for example, be synthesised as described in J. Chem. Soc. Perkin Trans. I (1985), pp. 1277-1284.
• Another suitable precursor monomer is 4-amino benzoic acid (see P. Ruelle, J. Chem. Soc. Perkin trans II, 1953 (1986).
• the process according to the invention is not restricted to the simultaneous use of precursor monomers of one type. Combinations of all types of precursor monomer are possible.
• precursor oligomers can be applied.
• the precursor monomers can be activated, for example, by means of a thermal or a photochemical treatment. In the process according to the invention any precursor monomer can be applied.
• Catalysts that can be added to the reaction mixture in the process according to the invention are generally known and can be chosen, for example, from the group of inorganic acids, such as hydrochloric acid, sulphuric acid, chlorosulphonic acid and nitric acid; Lewis acids such as compounds containing positive ions of iron, aluminium, tin, titanium, zirconium, chromium, manganese, cobalt, copper, molybdenum, tungsten, ruthenium, nickel, palladium and/or platinum; and a halogen, a sulphate, a nitrate, a sulphonate and/or an acetyl acetonate.
• inorganic acids such as hydrochloric acid, sulphuric acid, chlorosulphonic acid and nitric acid
• Lewis acids such as compounds containing positive ions of iron, aluminium, tin, titanium, zirconium, chromium, manganese, cobalt,
• Suitable catalysts are ozone, diazoniu salts, organic catalysts, for example benzoquinone, and persulphates, such as sodium persulphate, ammonium persulphate and potassium persulphate.
• persulphates such as sodium persulphate, ammonium persulphate and potassium persulphate.
• the activity of Ziegler-Natta catalysts and K 2 Cr 2 0 7 is good.
• oxidants with a good activity examples include FeCl 3 , FeBr 3 , FeCl 3 .6H 2 0, Fe(N0 3 ) 3 .9H 2 0, CuCl 2 .2H 2 0, K 3 Fe(CN) 6 , Fe(C10 4 ) 3 .9H 2 0, Fe 2 (S0 4 ) 3 .5H 2 0, CuS0 4 , Cu(N0 3 ) 2 and (C S H 5 ) 2 Fe + FeCl 4 - .
• Catalysts with an exceptionally good activity are iron(III)chloride and copper(I ⁇ )chloride.
• the catalyst is usually added in a molar ratio to the precursor monomer that is between 1:10 and 10:1. Preferably, this ratio is between 1:3 and 3:1. More preferably, this ratio is between 2:1 and 3:1.
• the polymer composition prepared using the process according to the invention contains a matrix polymer. If the polymer composition contains this matrix polymer it is extremely suitable for the preparation of moulded articles such as fibres, films and articles.
• the matrix polymer can be chosen within very broad limits. Depending on the requirements to be met by the polymer composition, for example as regards the mechanical properties, in principle any polymer may be chosen. Because of their processing properties thermoplastic polymers are preferred, but thermosetting polymers, such as resins and binders, are also extremely suitable as matrix polymer for certain applications.
• suitable matrix polymers are polyvinyl chloride or copolymers of vinyl chloride and other vinyl monomers, polyvinylidene fluoride or copolymers of vinylidene fluoride and other vinyl monomers, polystyrene or copolymers of styrene and other monomers, for example maleic anhydride and maleimide, polyacrylates or copolymers of an acrylate with other monomers, polyvinyl carbazole, polyolefins, such as polyethylene, ultrahigh molecular weight polyethylene (UHMWPE) and polypropylene, polyvinyl acetate, polyvinyl alcohol, polyesters, for example polyethylene terephthalate and polybutylene terephthalate, polycarbonates, polytetrafluoroethylene, polyether imides, polyimides, polyamides, polyamide-imides, polyethylene oxide, polybutadiene rubbers, and the like. If desired, a mixture of various polymers can be applied as matrix polymer.
• polymer in the polymer composition prepared using the process according to the invention is a consequence of the optimisation between the various desired properties, for example the electrically conducting properties on the one hand and the desired mechanical properties on the other.
• High concentrations of matrix polymer have an adverse effect on the conductivity in the resulting polymer composition, while low concentrations of matrix polymer may have an adverse effect on the desired mechanical properties.
• the weight ratio between the amount of matrix polymer and the amount of electrically conducting polymer in the polymer composition according to the invention may vary within broad limits. As a rule this ratio is between 1:99 and 99:1, preferably between 1:15 and 15:1.
• the reaction mixture is often present in a suitable dispersing agent.
• the dispersing agent is often chosen from the group consisting of water; aromatic compounds, for example benzene, toluene and xylene; alcohols, for example methanol and ethanol; hydrocarbons, for example pentane and hexane; ethers, such as dioxane, diethyl ether, ethyl methyl ether and tetrahydrofuran; ketones, for example acetone, diethyl ketone and methyl ethyl ketone; halogenated compounds, for example CHC1 3 , CH 2 C1 2 and carbon tetrachloride; esters, for example ethyl formate and ethyl acetate; and compounds for example acetonitrile, nitromethane, dimethyl sulphoxide, dimethyl formamide, triethyl phosphate, dimethyl acetamide and pyridine.
• the reaction mixture contains a pH buffer so that the pH of the mixture, which contains precursor monomer, catalyst and pH buffer, is approximately between 1 and 7.
• a suitable pH buffer is, for example, the conjugated base of a weak acid in the form of a carboxylate, for example a carbonate, a bicarbonate, an oxalate, an acetate, a formate and a phthalate; a phenolate containing an electron-attracting group, for example 3-nitrophenolate, 3-chlorophenolate and 3,5-dinitrophenolate; or a phosphate.
• amide for example urea, formamide, acetamide and N- acetyl benzamide.
• tertiary amines are triethyl amine, l,4-diazabicyclo[2.2.2]octane and aromatic amines, for example pyridine, imidazole, pyrazine and pyrimidine.
• a mixture of several buffers is used.
• the buffer contains urea.
• the buffer is added to the reaction mixture in at least such an amount that all protons released during the polymerisation are caught, the pH in the reaction mixture preferably not becoming higher than 7.
• a solution is, for example, prepared of precursor monomer, catalyst and buffer in a suitable solvent.
• the matrix polymer is added to the solution obtained. This can for example be done by impregnating a porous article moulded from the matrix polymer with the mixture of precursor monomer, catalyst and buffer. It is also possible for the matrix polymer to be dissolved in the mixture.
• the polymer composition can at a moment of one's own choice be heated or irradiated with a radiation source, so that the precursor monomers are deblocked. Deblocking can for example take place immediately after shaping of the polymer composition, but it is also possible to wait till a later point of time. Generally, this point of time will be chosen after the final form has been obtained.
• any catalyst residues and other low-molecular components can be removed by means of extraction and/or evaporation. These are generally known methods.
• the electrically conducting properties of the electrically conducting polymer that is obtained can be improved by means of an (oxidative or reducing) doping step, in which use can be made of the known doping techniques and reagents. These are mentioned, for example, in 'Handbook of conducting polymers' (T.A. Skotheim, Marcel Dekker Inc., New York, USA (1986)).
• the polymer composition prepared using the process according to the invention contains up to 60 weight percent of fillers and/or antioxidants. Examples of fillers are talc, fibres, pigments, kaolin, wollastonite and glass.
• Products obtained by the process according to the invention can be applied in widely divergent fields. Exponents of these are the fields of coatings and EMI- shielding devices. Examples of other suitable applications are conducting films.
• A transverse surface area [cm 2 ].
• the resulting film was heated for 5 minutes in a oven at a temperature of 110°C.
• the film colour gradually changed from reddish brown to black.
• the black film was extracted with acetone and air- dried.
• the specific conductivity of the film was measured to be 2.5 S/cm.
• the resulting black film was extracted with acetone and air-dried.
• the specific conductivity of the film was measured to be 11.2 S/cm.
• the impregnated film was heated for 5 minutes in a oven at a temperature of 120°C. After extraction the deep- red film was doped with NOSbF 6 (0.50 g in 30 ml of CH 3 CN) until the film colour (after some 10 seconds) changed into blue-grey .
• the resulting film was extracted with acetone and air-dried. Then, the entire cycle comprising impregnation, heating, doping, extraction and drying was repeated. The specific conductivity of the film was measured to be 20.0 S/cm.
• the resulting film was extracted with acetone and doped in the same manner as in example III. After the resulting film had been extracted with acetone and air- dried, the specific conductivity of the film was measured to be 28.0 S/cm.
• the resulting film was heated for 5 minutes in a oven at a temperature of 110°C.
• the film colour gradually changed from reddish brown to black.
• the film was extracted with acetone and air-dried. 2532 _ l ⁇ _
• the specific conductivity of the film was measured to be 0.5 S/cm.
• the grey, inhomogeneous film was subsequently extracted with acetone and air-dried.
• the specific conductivity of the film was measured to be 1.0 S/cm.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Polyoxymethylene Polymers And Polymers With Carbon-To-Carbon Bonds (AREA)

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• 1992
  • 1992-07-15 NL NL9201277A patent/NL9201277A/nl not_active Application Discontinuation
• 1993
  • 1993-06-11 JP JP6503955A patent/JPH06511283A/ja active Pending
  • 1993-06-11 AU AU45885/93A patent/AU4588593A/en not_active Abandoned
  • 1993-06-11 EP EP93916281A patent/EP0603381A1/en not_active Withdrawn
  • 1993-06-11 WO PCT/NL1993/000129 patent/WO1994002532A1/en not_active Application Discontinuation

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