Abstract: Propylene block copolymer containing per:100 parts by weight of a polymer (a) of propylene chosen from homopolymers and copolymers of propylene not containing more than 6% by weight of ethylene and/or of an alpha-olefin having from 4 to 6 carbon atoms,from 1 to 100 parts by weight of a polymer (b) of ethylene chosen from homopolymers and copolymers of ethylene not containing more than 90% by weight of propylene and/or of another alpha-olefin having from 4 to 6 carbon atoms,the said block copolymer additionally containing from approximately 0.001 to approximately 20% by weight of .alpha.,.omega.-diene-derived monomer units with respect to the total weight of the block copolymer.

Abstract: The present invention relates to a material for semiconductive screening and to use of the material in manufacturing cables and capacitors, and in electromagnetic shielding of electrical and electronic apparatus. The present invention further relates to cables and electrical and electronic apparatus containing the material. The semiconductive screening is formed of a polymer matrix containing one or more polymers and in which matrix 5% to 70% (by weight) of at least one conjugated non-doped or dedoped polymer is to be found in the dispersed state. In the absence of an electric field, the conductivity of the screening is very low, but said conductivity is an increasing function of the applied field (see curves 2 to 9 in the figure).

Abstract: The invention relates to a process for the preparation of polymers based on polyindoles by chemical polymerization of indole in the presence of an oxidizing agent and of a solvent.The invention also relates to compositions and electroconductive devices containing the polyindoles thus obtained and to the use of the polymers obtained.

Abstract: A polymer mixture, including at least one conductive polymer which has been dedoped to provide at least one dedoped conductive polymer; and at least one polar polymer. The polymer mixture has outstanding dielectric properties so that the polymer mixture is useful for producing electronic, optoelectrical, electrical and electromechanical devices.

Abstract: The invention relates to a process for the preparation of electrically conductive polymers derived from 3-alkylthiophenes by chemical polymerization of the 3-alkylthiophene by means of a ferric salt, an alkyl halide and water.The invention also relates to electrically conductive devices containing the poly(3-alkylthiophenes) obtained and a thermoplastic polymer.

Abstract: The invention relates to a process for the preparation of electrically conducting polymers based on polythiophenes by chemical polymerization of thiophene by means of a ferric salt, an alkyl halide and water.The invention also relates to the electrically conducting devices containing the polythiophenes obtained and a thermoplastic polymer.

Abstract: The invention relates to a process for the preparation of electrically conducting polymers based on polythiophenes by chemical polymerization of thiophene by means of a ferric salt, an alkyl halide and water.The invention also relates to the electrically conducting devices containing the polythiophenes obtained and a thermoplastic polymer.

Abstract: A process for the preparation of a polymer which is electrically conductive and which is based on polythiophene, the process including polymerizing thiophene in a reaction medium including thiophene, from 2.5 to 20 moles of an anhydrous ferric salt per mole of thiophene, from 0.04 to 1 liter of an alkyl halide per gram of thiophene, and from 0.1 to 5% by weight of water introduced into the reaction medium based on the amount of alkyl halide.