Abstract: Thermotropic melt processable liquid crystalline aromatic polyesters comprising units derived from a dicarboxylic acid and from a mixture of aromatic diols in which from 50% to 80% is (1-phenylethyl)hydroquinone and from 20% to 50% is hydroquinone.

Abstract: The present invention relates to copolyethers comprising copolymers of 7,oxa-bicyclo(2,2,1)heptane, and its alkyl-derivatives, with one or more single-ring or condensed-rings cycloaliphatic ethers, comprising the characteristic group; ##STR1## wherein R' is hydrogen and R" is H, a halogen, or an alkyl radical containing a small number of carbon atoms, and which may also be halogen-substituted.If the ether contains one ring only, it contains from 5 to 12 atoms in the ring, and if it contains a condensed-ring system, it contains a total number of from 10 to 18 atoms in the rings.Those copolyethers show a anisotropic behaviour in the molten state, and therefore have liquid-crystal properties.

Abstract: The present invention relates to copolyethers constituted by copolymers of 7,oxa-bicyclo(2,2,1)heptane, and its alkyl-derivatives, with one or more cycloaliphatic ethers, comprising from 2 to 4 carbon atoms in their ring.These copolyethers show an anisotropic behavior in the molten state, and therefore are endowed with liquid-crystal properties.

Abstract: Thermotropic liquid-crystalline aromatic polyesters processable in the molten state, comprising units derived from at least one dicarboxy aromatic acid having the formula:HOOC--Ar.sub.1 --O--Ar.sub.2 --COOH (1)wherein Ar.sub.1 and Ar.sub.2 are aromatic radicals from aromatic diols, and, possibly, from other diacids and/or hydroxy acids.

Abstract: The present invention relates to copolyethers comprising copolymers of 7,oxa-bicyclo(2,2,1)heptane, and its alkyl-derivatives, with one or more cycloaliphatic ethers, comprising from 2 to 4 carbon atoms in their ring. These copolyethers show an anisotropic behavior in the molten state, and therefore have liquid-crystal properties.

Abstract: Catalyst components which comprise the reaction product of a Ti compound and a Mg dihalide and which are in the form of spherical particles having an average diameter of 1 to 100 microns, a surface area of 300 to 500 m.sup.2 /g, and a porosity of 0.3 to 0.4 cc/g are disclosed, as are catalysts also in the form of spherical particles prepared therefrom and useful in the polymerization of ethylene and of alpha-olefins CH.sub.2 .dbd.CHR in which R is alkyl radical having from 1 to 6 carbon atoms, and the polymerization of the alpha-olefins therewith.