Abstract: The process for manufacturing a polarizing film based on polyvinyl alcohol and at least one dichroic substance by casting or extrusion of a mixture of polyvinyl alcohol and a solvent, whereby the polyvinyl alcohol contains the dichroic substance, drying and stretching of the film by between 300 and 1200%, whereby, depending on the width of the unstretched film b.sub.o, a stretch gap l.sub.o is provided, satisfying the condition b.sub.o /l.sub.o <3, leads to higher dichroic extinction quotients.

Abstract: The title compounds can be prepared by reaction of a styrene derivative with ethylene in the presence of a nickel catalyst which carries a phosphorus-oxygen chelate ligand, at a temperature of 20.degree.to 160.degree. C. and an ethylene pressure of 1 to 200 bar. Styrene derivatives extended with ethylene, of the formula ##STR1## in which R.sup.19 denotes hydrogen, C.sub.1 -C.sub.4 -alkyl, vinyl or chlorine and R.sup.38 denotes C.sub.1 -C.sub.4 -alkyl, C.sub.2 -C.sub.4 -alkenyl, C.sub.2 -C.sub.7 -acyl, flourine, chlorine or bromine andm assumes values of 4-104,with the exception of compounds wherein R.sup.19 denotes hydrogen and R.sup.38 denotes i-butyl or benzoyl, and m assumes the value 4, are new.

Abstract: Nickel compounds which can be produced by reacting a nickel(O) compound or a nickel compound, which can be converted in situ into a nickel(O) compound, with an adduct or a mixture of maleic acid anhydride and a tertiary phosphine, optionally with a compound of the formula (I) ##STR1## wherein X represents O, NR.sup.4 or ##STR2## and n represents zero or one,and optionally with an organoaluminium compound, are suitable for the homo-and copolymerization of 1-olefins and for the polymerization of acetylene.

Abstract: Olefins such as ethylene can be polymerized with a catalyst which comprises nickel compounds obtained by reacting a nickel-(O) compound or a nickel compound which may be converted in situ into a nickel-(O) compound with an adduct or a mixture of a quinoid compound and a tertiary phosphine and with a compound corresponding to the following general formula: ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 independently represent C.sub.1 -C.sub.20 alkyl, C.sub.2 -C.sub.20 alkenyl, C.sub.6 -C.sub.12 aryl or C.sub.3 -C.sub.8 cycloalkyl optionally substituted by halogen, hydroxy, C.sub.1 -C.sub.20 alkoxy, nitro or C.sub.6 -C.sub.12 aryloxy; also C.sub.6 -C.sub.12 aryl-C.sub.1 -C.sub.20 alkyl, C.sub.6 -C.sub.12 aryl-C.sub.2 -C.sub.20 alkenyl, C.sub.1 -C.sub.20 alkyl-C.sub.6 -C.sub.12 aryl, C.sub.1 -C.sub.20 alkyl-C.sub.3 -C.sub.8 cycloalkyl and C.sub.6 -C.sub.12 aryl-C.sub.3 -C.sub.8 cycloalkyl, di-C.sub.1 -C.sub.4 alkylamino, optionally substituted phenoxy or alkoxy; R.sup.4, R.sup.5 and R.sup.

Abstract: Nickel-compounds, producible by reaction of Nickel-(O)-compound or a compound convertible thereto in situ with two different compounds corresponding to the following formulae ##STR1## are useful as catalysts in the polymerization of olefins.

Abstract: The title compounds can be prepared by reaction of a styrene derivative with ethylene in the presence of a nickel catalyst which carries a phosphorus-oxygen chelate ligand, at a temperature of 20.degree. to 160.degree. C. and an ethylene pressure of 1 to 200 bar. Styrene derivatives extended with ethylene, of the formula ##STR1## in which R.sup.19 denotes hydrogen, C.sub.1 -C.sub.4 -alkyl, vinyl or chlorine and R.sup.38 denotes C.sub.1 -C.sub.4 -alkenyl, C.sub.2 -C.sub.7 -acyl, flourine, chlorine or bromine andm assumes values of 4-104,with the exception of compounds wherein R.sup.19 denotes hydrogen and R.sup.38 denotes i-butyl or benzoyl, and m assumes the value 4, are new.