Abstract: The invention provides a supported chromium catalyst system comprising a chromium catalyst precursor bound via at least one heteroatom to a functionalised support, said heteroatom being connected to said support via an organic group.

Abstract: A process for olefin polymerization in a reaction vessel, said process comprising polymerizing at least one &agr;-olefin in a polymerization stage employing a catalyst feed comprising 1) a first catalyst composition having at least two active catalytic sites capable of producing a first set of polymer components; 2) a second catalyst composition having at least two active catalytic sites capable of giving essentially the same set of polymer components as produced by the catalyst in feed (1) under the same polymerization conditions but these components in a different ratio to those produced by the catalyst composition of feed (1); wherein the amounts of catalyst compositions (1 and 2) fed into the reaction vessel are independently controlled.

Abstract: A process for the polymerization of ethylene and optionally &agr;-olefins to form ethylene homopolymer or copolymers having a broad molecular weight distribution, comprising polymerization of 100-80 wt. % of ethylene and 0-20 wt. % of comonomer in the presence of two independent, simultaneously present catalysts A and B, wherein catalyst A, deposited on an inorganic support, comprises chromium in a predominantly oxidant state of 2 and catalyst B comprises a bis-cyclopentadienyl chromium compound reacted with an inorganic support.