Abstract: The processability of a polybutadiene with a high content of 1,4-cis-structure is improved by means of the addition of PCl.sub.3 before the polymerization reaction is quenched and when Mooney viscosity of polybutadiene has reached a prefixed value, preferably lower than, or equal to 30; the polymerization of butadiene is carried out in a solution in an aliphatic or cycloaliphatic solvent, in the presence of a catalytic system based on rare earths, preferably a neodymium-based catalytic system.

Abstract: Coupling agents of general formula ##STR1## and their use in a method for the termination of living polymers obtained by anionic polymerization of diene and/or vinylaromatic monomers.

Abstract: The invention relates to a continuous process for the manufacture of butyl rubber in which the monomers are polymerized using a halogenated polymerization medium in a self-cleaning screw extruder at a constant pressure under boiling plug-flow conditions by means of a modified aluminium halide catalyst which operates at high temperature (relative to prior art very low temperatures of e.g. -100.degree. C.). In contrast to prior art slurry processes, the polymerization mixture forms a sticky, highly viscous mass which is conveyed by screw action to the extruder outlet as polymerization proceeds. The butyl rubber product is separated at a high concentration from vapors of unreacted monomers and polymerization medium which are recycled.

Abstract: Coupling agents of general formula ##STR1## and their use in a method for the termination of living polymers obtained by anionic polymerization of diene and/or vinylaromatic monomers.

Abstract: Multifunctional anionic initiators having the general formula: ##STR1## and process for synthesizing said initiators and their use in polymerizing dienic monomers and for making block polymers.

Abstract: An improved process is described for preparing conjugate diolefin polymers or copolymers having a high content of 1,4-cis units and high chain linearity, the process using a particular catalytic system prepared from a compound of a metal chosen from those of Group III B of the Periodic System which have an atomic number of between 21 and 103, preferably neodymium, an organic halogen derivative, and an aluminium alkylhydride or trialkyl.

Abstract: An alpha-olefin such as ethylene is polymerized in the presence of a catalyst system consisting of (1) an alkyl-halide, alkyl-derivative or hydride of a metal belonging to one of the first three groups of the periodic system and (2) the combination product of a transition metal chloride and titanium trichloride, supported on a previously chlorinated material such as chlorinated .alpha.-alumina having a high superficial area.

Abstract: An alpha-olefin such as ethylene is polymerized in the presence of a catalyst system consisting of (1) an alkyl-halide, alkyl-derivative or hydride of a metal belonging to one of the first three groups of the periodic system and (2) the combination product of a transition metal chloride and titanium trichloride, supported on a previously chlorinated material such as chlorinated .gamma.-alumina having a high superficial area.

Abstract: An alpha-olefin such as ethylene is polymerized in the presence of a catalyst system consisting of (1) an alkyl-halide, alkyl-derivative or hydride of a metal belonging to one of the first three groups of the periodic system and (a) the combination product of a transition metal chloride and titanium trichloride said transition metal chloride being derived from the reaction of a transition metal carbonyl and titanium tetrachloride.

Abstract: Ethylene is polymerized through the use of an improved catalyst system consisting of a carrier such as neodymium oxide having a high superficial area, an aluminum compound such as triisobutylaluminum and the combination product of titanium trichloride and an isostructural chloride of another transition metal prepared by impregnating the carrier with a solution of a carbonyl derivative of the other transition metal, refluxing the impregnated carrier with titanium tetrachloride until that carbonyl derivative is converted to the chloride of the other transition metal, and then removing the excess of titanium tetrachloride.