Abstract: A thermoplastic composition based on a polyolefin and a vinyl aromatic polymer, having an improved combination of physical, mechanical and thermal properties, comprising:from 40 to 80% by weight of a vinyl aromatic polymer (A) containing, as an elastomeric component, from 0.5 to 5% by weight of a vinyl aromatic monomer - conjugated diene linear block polymer and from 5 to 15% of a diene rubber, from 5 to 50% by weight of a polyolefin (B) and from 10 to 50% by weight of an olefinic elastomer (C) containing, grafted thereon, a vinyl aromatic polymer, wherein the molar ratio between the vinyl aromatic polymer and the olefinic elastomer in the grafted phrase is greater than 0.8, the sum of components (A), (B) and (C) being equal to 100%.

Abstract: A solid component of catalyst for the (co)polymerization of ethylene, including magnesium, halogen and titanium, is prepared:(i) by dissolving a magnesium dialkyl, a silicon halide and at times also an alkyl halide, in an inert organic solvent and maintaining contact until a granular solid precipitates;(ii) putting this granular solid in contact and making it react with a titanium halide, alkoxide or halogen-alkoxide, to produce a solid component of catalyst; and(iii) activating this solid component of catalyst by contact with aluminium alkyl halide, if a titanium alkoxide or halogen-alkoxide has been used in phase (ii).

Abstract: A process for the preparation of a solid component of a catalyst active in the (co)polymerization of ethylene and able to form (co)polymers of ethylene having from middle to wide distribution of molecular weight and monomodal distribution of molecular weights, in processes operating in a single step, in suspension or in the gaseous phase. Said solid component of a catalyst contains magnesium, chlorine, silicon, titanium and at least another transition metal on a solid, granular and porous carrier and is obtained by treating the carrier, in succession, with: a compound of a metal selected from hafnium, zirconium or vanadium; a magnesium dialkyl or magnesium alkyl halide; a silicon chloride; and a titanium compound.

Abstract: Flame-retardant thermoplastic composition including a styrene polymer containing thoroughly incorporated therein an effective quantity of a synergetic mixture composed of a chlorinated hydrocarbon compound containing at least 40% by weight of combined chlorine, an inorganic compound containing oxygen of a metal belonging to group III or IV of the periodic table, and polytetrafluoroethylene having a particle size which is less than 20 microns.

Abstract: Moulding thermoplastic compositions, endowed with improved mould release characteristics, comprising:A) an impact resistant vinyl aromatic copolymer consisting of an ethylenically unsaturated nitrile, a vinyl aromatic monomer and a rubber;B) an engineering polymer; andC) an effective amount of a release agent constituted by a synergistic mixture of an ester of a C.sub.16 -C.sub.18 acid with glycerol and an ester of a saturated aliphatic C.sub.10 -C.sub.20 acid with a C.sub.4 -C.sub.6 aliphatic alcohol.The physical-mechanical properties of the compositions at high moulding temperatures can be improved by addition of an effective amount of a bis(alkyl-phenyl)pentaerythritol diphosphite.The compositions can, furthermore, contain in addition a grafted polymer consisting of an elastomeric core having a Tg lower than 10.degree. C. and containing vinyl monomer chains grafted thereon.

Abstract: The thermal and hydrolytic stabilities of the elastomeric thermoplastic copolyether-esters are remarkably improved by the addition of a synergistic mixture consisting of an tri (hydroxybenzyl) benzene and of a bis (alkyl-phenyl) pentaerythritol diphosphite.The copolyether-esters thus compounded find use in the extrusion, blow and injection molding technologies.

Abstract: A process for preparing aromatic polyesters having excellent physico-mechanical and solvent-resistance properties, consisting in reacting at least a dialkyl ester of an aromatic diacid with an aromatic polycarbonate and/or an aromatic dialkyldicarbonate in the presence of an esterification or transesterification catalyst.

Abstract: A solid component of catalyst for the (co)polymerization of ethylene is composed of a silica carrier and a catalytically active part which includes titanium, magnesium, chlorine and also alkoxy groups, and is obtained: by suspending an activated silica in an ethanolic solution of magnesium chloride; by contact of the suspension with an alkoxy or halogen alkoxyde of titanium and with a silicon halide; by eliminating the ethanol from the resulting suspension in order to recover a solid matter; and by making this solid react with an aluminium alkyl chloride.

Abstract: Process for preparing shaped bodies with integrated polyurethane skin, which process comprises:(a) charging to a closed mould for rotational moulding a first premixed reactive polyurethane system;(b) causing the mould to rotate, according to rotational moulding technology, for a long enough time to form a thin layer of partially polymerised material on the inner surface of said mould; and(c) discontinuing the rotation and charging to the mould a reactive material which will fill the inner mould hollow.

Abstract: A procedure is described for the preparation of a vanadium bis-arene, [V(arene).sub.2 ], starting from vanadium oxychloride, aluminium metal, aluminium trichloride and an arene, wherein:(a) vanadium oxychloride (VOCl.sub.3), active aluminium metal, and aluminium trichloride are put in contact with each other, in a liquid arene, to transform the vanadium oxychloride into the complex compound [V(arene).sub.2 ].sup.+ [AlCl.sub.4 ].sup.- ;(b) a liquid cyclic or acyclic or acyclic ether is added to the reaction product of step (a) to reduce [V(arene).sub.2 ].sup.+ to [V(arene).sub.2 ]; and(c) the vanadium bis-arene [V(arene).sub.2 ] is recovered from the reacton product of step (b).The vanadium bis-arenes thus obtained are use in the preparation of catalysts for the polymerization of olefins.

Abstract: Thoughened thermoplastic compositions are described having a good balance of mechanical, thermal and process properties, comprising:at least a polyphenylene ether,at least a polyamide,an elastomeric copolymer containing a vinyl aromatic polymer grafted on an olefinic elastomer, andan organic diisocyanate.

Abstract: Polymeric compositions characterized by their excellent thermal stability containing a polyphenylene ether or one of its blends with at least one (co)polymer of styrene and at least one compound belonging to the group of linear and/or cyclic beta diketones.Beta-diketones are capable of giving polyphenylene ether and/or its blends with styrenic polymers a long-lasting thermal stability in the molten state and of guaranteeing sufficient fluidity to ensure better processability compared to the same polymers in the known art.

Abstract: Polymeric compositions based on at least one polyphenylene ether, obtained from the (co)polymerization by oxidative coupling of one or more substituted phenols, either alone and/or together with at least one (co)polymer of styrene, are thermically stabilized by adding at least one compound having the structural formulaR--C.tbd.C--COOH (I)where R has the meaning described in the text. These compositions are characterized by the fact that they have excellent thermal stability in the molten state, are long-lasting and have a much better fluidity and processability compared to the corresponding polymeric blends which do not contain (I).

Abstract: A solid component of a catalyst for the (co)polymerization of ethylene is composed of a silica carrier and a catalytically active part which includes titanium, magnesium, chlorine and also alkoxy groups, and is obtained: by suspending an activated silica in an ethanolic solution of magnesium chloride; by contact of the suspension with an alkoxy or halogen alkoxyde of titanium and with a silicon halide; by eliminating the ethanol from the resulting suspension in order to recover a solid matter; and by making this solid react with an aluminum alkyl chloride.

Abstract: Graft copolymers are prepared by means of a two-step polymerization process, in emulsion: in the first step, a vinylaromatic monomer and an acryl or metacryl monomer are grafted on a monomodal polybutadiene latex constituted of particles of diameter comprised within the range of from 800 to 2500 .ANG.. The polymerization/grafting reaction is continued up to a 70-90% conversion, at which time a further portion of monomodal polybutadiene is added, together with further amounts of said monomers, always in emulsion.

Abstract: Lanthanide and actinide catalyst systems normally appear to be "pseudo-living" when they are used to polymerize conjugated diolefin monomers into polymers. Polymerizations which are catalyzed with such catalyst systems produce polymers which have increasingly high molecular weight as monomer conversions are increased. Consequently, any change in polymerization time or conversion may affect the polymer's ultimate molecular weight. This has made controlling the molecular weight of polymers which are made utilizing lanthanide and actinide catalysts difficult.It has been unexpectedly discovered that vinyl halides can be used as molecular weight regulators for polymerizations which are catalyzed with lanthanide and actinide catalyst systems.

Abstract: Self-extinguishing polycarbonates essentially consisting of mixtures of polycarbonates with at least one salt of metals of the I and/or of the II A and B Groups of the Elements Periodic Table, of particular inorganic compounds, and possibly with at least one halogenated organic compound.

Abstract: Composition of self-extinguishing polycarbonate comprising, in mixture, a not halogenated aromatic polycarbonate and a mixture of additives conferring self-extinguishing characteristics to the same polycarbonate, formed by: (a) salt of alkaline metal, of alkaline-earth metal or of zinc, or mixed salt of said metals, of ethylenediaminotetraacetic acid; (b) oligomer of polycarbonate from tetrabromobisphenol-A terminated with phenol, or decabromodiphenyloxide; and (c) polytetrafluoroethylene.

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.