Abstract: In a process for the anionic polymerization of vinylaromatic monomers or dienes in the presence of a lithium organyl or lithium alcoholate and a magnesium and/or an aluminum compound, a sterically hindered phenol or amine is added.

Abstract: A process for the continuous anionic polymerization or copolymerization of styrene or diene monomers using an alkali metal alkyl compound as polymerization initiator is carried out in the presence of an alkyl- or arylmetal compound of an element which occurs in at least divalent form as rate regulator, preferably under non-isothermal conditions and without back-mixing in a tubular or tube-bundle reactor, preferably using an alkyl- or arylmetal compound A of the formula R1M1 and an alkyl- or arylmetal compound B of the formula R2nM2 in a molar ratio between B and A of from 0.1:1 to 500:1, where M1 is Li, Na or K; R1 is hydrogen, C1-C20-alkyl, C6-C20-aryl, or C7-C20-alkyl-substituted aryl; M2 is an n-valent element from group 2a, 2b or 3a of the Periodic Table; and R2 is hydrogen, halogen, C1-C20-alkyl or C6-C20-aryl; and a special anionic polymerization initiator containing no Lewis base.

Abstract: In a process for the homopolymerization of vinylaromatic monomers or the copolymerization of vinylaromatic monomers and dienes, the monomers are polymerized in the presence of at least one alkali metal organyl, at least one magnesium organyl and at least one aluminum organyl. The invention also provides an initiator composition for carrying out the process.

Abstract: In a process for the homopolymerization of vinylaromatic monomers or the copolymerization of vinylaromatic monomers and dienes in the presence of at least one alkali metal compound and at least one compound of an element of group 3a of the Periodic Table of the elements, the compounds contain, based on the sum of molar equivalents of alkali metal and elements of group 3a, in each case a) from 0.1 to 3.9 molar equivalents of oxygen, sulfur, nitrogen or phosphorus and b) from 0.1 to 3.9 molar equivalents of an organyl ligand.

Abstract: Disclosed are a process for the preparation of an initiator composition comprising an alkali metal organyl and an aluminum organyl and a process for the polymerization of anionically polymerizable monomers.

Abstract: The initiation system is composed of at least one initiator and at least one amino alcoholate of the formula: 1

Abstract: This catalyst has the general formula VX.sub.3, mAIX.sub.3, nZ, wherein X is a halogen atom, Z is at least one at least partially halogenated, branched or unbranched, saturated hydrocarbon, m is between 0.1 and 10, and n is between 1 and 300. To prepare it, a vanadium halide VX.sub.2 and/or VX.sub.3 is coground with an aluminum halide AlX.sub.3, and then at least one halogenated hydrocarbon Z is added to the mixture obtained in proportions corresponding to the chosen values of m and n. The invention also relates to the (co)polymerization of alpha-olefins at 20.degree.-350.degree. C. in the presence of a catalyst system comprising at least one catalyst as defined above and at least one organometallic activator.

Abstract: The invention relates to a process for the preparation of conductive polymers or prepolymers and to conductive polymers or prepolymers.The process of the invention consists of reacting a polymer containing ethylenic unsaturations such as a hydroxytelechelic polybutadiene with a silane compound of formula ##STR1## in which R.sub.1 denotes a hydrocarbon group containing at least one heteroatom bearing mobile electrons, such as the oxygen of an ether group, andR.sub.2 and R.sub.3 denote a substituted or unsubstituted organic residue or a group R.sub.1.The polymer obtained is precipitated by the addition of a compound which is not a solvent for the polymer, and is separated from the reaction medium.The polymers obtained have an electrical conductivity which is multiplied by a factor of 10.sup.5 relative to the unmodified polymer.The present invention applies in particular in the field of the polymer industry.

Abstract: A cement for fixing a bone prosthesis, the cement containing:(a) a solid phase comprising firstly polymethylmethacrylate and a copolymer of methyl methacrylate with an acrylate or a methacrylate of another alcohol, both in powder form, and secondly an organic peroxide suitable for generating free radicals; and(b) a liquid phase comprising methyl methacrylate and an accelerator for accelerating decomposition of the organic peroxide.The copolymer is an oligomer, and the liquid phase includes as the accelerator for accelerating decomposition of said organic peroxide an acrylate or a methacrylate carrying a tertiary amine function, and as a cross-linking agent a compound having at least two functions in its molecule suitable for reacting with the reactive functions carried by the polymers of the solid phase, or else a double bond and a function suitable for reacting with the reactive functions carried by the polymers of the solid phase.

Abstract: New organo-lithium initiators, their synthesis, and their use. The initiators have the formula: ##STR1## in which R" is either a hydrogen atom or a methyl radical; either n is 1, in which case R'=H and m and p are integers, the sum of which is between 0 and 10 inclusive, or n is 2, R' then being an alkyl radical of 2 to 8 carbon atoms and m=p=o; and R is an alkyl radical of 1 to 4 carbon atoms.The initiators are prepared by reacting compounds of the formula; ##STR2## with an alkyl-lithium RLi in a non-polar solvent in the absence of any polar solvent or complexing agent.The initiators are used to prepare polydienes of high stereoregularity by reacting with a diene, and the polydiene is used to prepare a three-block or star copolymer by reacting with an anionically polymerizable monomer.

Abstract: Organo-lithium compounds of the formula: ##STR1## wherein R is an alkyl group of up to 5 carbon atoms, R' is either hydrogen or an alkyl group of up to 5 carbon atoms and n is an integer from 2 to 10. These bifunctional organo-lithium compounds are prepared without the use of any polar or complexing agent and are useful as polymerization initiators for the production of block copolymers.

Abstract: New organo-lithium initiators, their synthesis, and their use. The initiators have the formula: ##STR1## in which R" is either a hydrogen atom or a methyl radical; either n is 1, in which case R' = H and m and p are integers, the sum of which is between 0 and 10 inclusive, or n is 2, R' then being an alkyl radical of 2 to 8 carbon atoms and m =p =0; and R is an alkyl radical of 1 to 4 carbon atoms.The initiators are prepared by reacting compounds of the formula: ##STR2## with an alkyl-lithium RLi in a non-polar solvent in the absence of any polar solvent or complexing agent.The initiators are used to prepare polydienes of high stereoregularity by reacting with a diene, and the polydiene is used to prepare a three-block or star copolymer by reacting with an anionically polymerizable monomer.

Abstract: Organo-lithium compounds of the formula: ##STR1## wherein R is an alkyl group of up to 5 carbon atoms, R' is either hydrogen or an alkyl group of up to 5 carbon atoms and n is an integer from 2 to 10. These bifunctional organo-lithium compounds are prepared without the use of any polar or complexing agent and are useful as polymerization initiators for the production of block copolymers.

Abstract: New organo-lithium initiators, their synthesis, and their use. The initiators have the formula: ##STR1## IN WHICH R" is either a hydrogen atom or a methyl radial; either n is 1, in which case R' = H and m and p are integers, the sum of which is between 0 and 10 inclusive, or n is 2, R' then being an alkyl radical of 2 to 8 carbon atoms and m = p = 0; and R is an alkyl radical of 1 to 4 carbon atoms.The initiators are prepared by reacting compounds of the formula: ##STR2## WITH AN ALKYL-LITHIUM RLi in a non-polar solvent in the absence of any polar solvent or complexing agent.The initiators are used to prepare polydienes of high stereoregularity by reacting with a diene, and the polydiene is used to prepare a three-block or star copolymer by reacting with an anionically polymerizable monomer.

Abstract: Organo-lithium compounds of the formula: ##STR1## wherein R is an alkyl group of up to 5 carbon atoms, R' is either hydrogen or an alkyl group of up to 5 carbon atoms and n is an integer from 2 to 10. These bifunctional organo-lithium compounds are prepared without the use of any polar or complexing agent and are useful as polymerization initiators for the production of block copolymers.