Abstract: Disclosed are catalysts for the polymerization of alpha-olefins which comprise the reaction product of: (a) an Al-alkyl compound; (b) a silicon compound containing at least one Si—OR or Si—OCOR or Si—NR2 bond, R being a hydrocarbyl radical; (c) a solid comprising, as essential support, a Mg dihalide in active form and, supported thereon, a Ti halide or a halo-Ti-alcoholate and a particular type of electron donor compound. The present invention refers to new supported components of catalysts for the polymerization of CH2═CHR olefins wherein R is an alkyl radical with 1 to 4 carbon atoms, or an aryl radical, and mixtures of said olefins with ethylene and the catalysts obtained from said components.

Abstract: Catalyst-forming components and catalysts for the polymerization of olefins based on said components are disclosed. The catalysts comprise the reaction product of: (a) an Al alkyl compound; (b) a silicon compound containing at least a Si—OR or Si—OCOR or Si—NR2 bond, R being a hydrocarbyl radical; and (c) a solid comprising, as essential support, a Mg dihalide in active form and, supported thereon, a Ti halide or a halo-Ti-alcoholate or said halogenated Ti compound and a silicon compound as defined in (b) in a molar ratio with the supported Ti compound from 1.0 mole to 5 moles of silicon compound per mole of Ti compound. The present invention refers to new supported components of catalysts for the polymerization of CH2═CHR olefins wherein R is an alkyl radical with 1 to 4 carbon atoms, or an aryl radical, and mixtures of said olefins with ethylene, and to the catalysts obtained from said components.

Abstract: The present invention relates to supported catalysts for the polymerization of alpha-olefins which comprise the reaction product of: (a) an Al-alkyl compound; (b) a silicon compound containing at least one Si—OR or Si—OCOR or Si—NR2 bond, R being a hydrocarbyl radical; (c) a solid comprising, as essential support, a Mg dihalide in active form and, supported thereon, a Ti halide or a halo-Ti-alcoholate and a particular type of electron donor compound. The present invention also relates to supported catalyst components.

Abstract: Process for the preparation of vinylaromatic copolymers reinforced with rubber which comprises:a) dissolving a dienic rubber (i) and/or a linear block elastomer, vinylaromatic monomer-1,3 conjugated diene (ii), in a mixture comprising at least one vinylaromatic monomer and a pair of solvents consisting of a polar solvent and a nonpolar solvent;b) polymerizing the solution thus obtained, possibly in the presence of an initiator.

Abstract: Process for the preparation of ABS which comprises:a) preparing a solution consisting of a diblock linear rubber of the type S-B dissolved in a mixture of monomers comprising styrene and acrylonitrile;b) feeding to the solution of step (a) at least one preformed ABS resin having an average volumetric diameter of the rubber particles contained in the polymeric matrix of more than 1.5 .mu.;c) dissolving the preformed ABS in the solution of step (a);d) feeding in continuous the solution thus obtained to a polymerization reactor for ABS resins;e) polymerizing the final solution to produce an ABS with a multimodal morphology.

Abstract: A rubber-reinforced vinyl aromatic (co)polymer comprising a polymeric matrix and a rubber phase dispersed and/or grafted in the polymeric matrix and consisting of a mixture of(i) a diene rubber and(ii) a vinyl aromatic monomer/conjugated 1,3-diene linear block copolymer, said block copolymer having a diene content exceeding 80 wt % and, respectively, a vinyl aromatic monomer content of less than 20 wt %.

Abstract: Disclosed are catalysts for the polymerization of alpha-olefins which comprise the reaction product of:(a) an Al alkyl compound;(b) a silicon compound containing at least a Si--OR or Si--OCOR or Si--NR.sub.2 bond, R being a hydrocarbyl radical;(c) a solid comprising, as essential support, a Mg dihalide in active form and, supported thereon, a Ti halide or a halo-Ti-alcoholate and a particular, selected type of electron-donor compound.

Abstract: Disclosed are catalysts for the polymerization of alpha-olefins which comprise the reaction product of:(a) an Al alkyl compound;(b) a silicon compound containing at least a Si--OR or Si--OCOR or Si--NR.sub.2 bond, R being a hydrocarbyl radical;(c) a solid comprising, as essential support, a Mg dihalide in active form and, supported thereon, a Ti halide or a halo-Ti-alcoholate and a particular, selected type of electron-donor 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: Bimodal star-block copolymers are disclosed containing from 60 to 90% by weight of an aromatic vinyl monomer and from 40 to 10% by weight of a conjugated diene, said copolymers having the general formula:(S--S.sub.1 --B/S.sub.2 --B.sub.1).sub.m --X--(B.sub.1 --S.sub.2 /B--S.sub.1).sub.nwherein X is a polyfunctional radical, m and n are integers (being m.ltoreq.n) the sum of which is between 3 and 20 and equal to the functionality degree of the radical X, S and S.sub.1 are polymer blocks of an aromatic vinyl monomer, B.sub.1 is an elastomeric copolymer of conjugated dienic units, containing up to 20% of all the dienic units of the copolymer, and B/S.sub.2 and S.sub.2 /B are blocks of copolymers of aromatic vinyl monomer and conjugated diene of the random and/or tapered type.

Abstract: Block copolymers of ethylene and/or alpha-olefins, in particular propylene, with vinyl aromatic monomers, comprising at least two polymeric blocks, one of which being a polyolefinic block and the other having a stereoregular structure and being formed by vinyl aromatic monomer units.

Abstract: Thermoplastic compositions based on polyphenylenether resins, endowed with improved mechanical, thermal and solvent-resistance characteristics, comprising, for 100 parts by weight of polyphenylenether resin:(a) from 0 to 90 parts by weight of a thermoplastic polymer other than polystyrene and incompatible with the polyphenylenether resin, and(b) from 1 to 90 parts by weight of a polymeric compatibility-promoting agent comprising one or more blocks of vinylacromatic monomeric units compatible with the polyphenylenether resin, and one or more blocks of monomeric units of the same nature as the thermoplastic polymer (a), or compatible with that polymer.