Abstract: The present invention relates to butene-1 homopolymers, or copolymers containing up to 20% by weight of alpha olefins having from 2 to 10 carbon atoms other than butene-1, characterized by the following properties: (i) a Molecular Weight Distribution (MWD) in terms of Mw/Mn, measured by GPC analysis according to the method specified, of lower than 6; and (ii) a melt strength (measured according to the method specified below) higher than 2.8.

Abstract: Catalyst components for the polymerization of olefins CH2?CHR, wherein R is hydrogen or a hydrocarbon radical having 1-12 carbon atoms, comprising Mg, Ti, Cl, OR groups, where R is a C1-C10 alkyl group optionally containing heteroatoms, and an ether having two or more ether groups, characterized by the fact that the Mg/Ti weight ratio is lower than 3 from 2 to 6.5 the Cl/Ti weight ratio is from 1.5 to 6, the OR/Ti weight ratio is from 0.5 to 3.5 and at least 50% of the Titanium atoms are in a valence state lower than 4. The said catalyst components allow the preparation of ethylene copolymers with a low content of xylene soluble fractions.

Abstract: Solid catalyst components comprising Ti,Mg, halogen and internal electron-donor compound selected from the 1,3-diethers of formula (I) in which R is a C1-C10 alkyl group, R1 is a linear or branched primary alkyl radical having at least three carbon atoms, optionally containing a heteroatom, and R2 is a secondary alkyl or cycloalkyl radicals different from i-propyl, optionally containing a heteroatom. The catalysts obtained by using as internal electron-donor compound the said 1,3-diethers display in the (co)polymerization of olefins an excellent balance of activity and stereospecificity that cannot be reached with the ethers known in the art.