Arkema France

Pascal Nicol

Serge Hub

Jacques Cochet

A method for manufacturing polyethylene or an ethylene copolymer, including a step of free radical polymerization or copolymerization of the ethylene at an initiation temperature varying from 150&#xb0; C. to 200&#xb0; C., at a pressure varying from 500 to 3000 bar, in the presence of a peroxidic polymerization initiator selected from among the peroxide compounds of formula (I) in which R1 and R8 are, separately, a C2-C6 alkyl group; R2, R3, R6 and R7 are, separately, a C1-C5 alkyl group; and R4 and R5 are, separately, a C1-C6 alkyl group.

Free radical polymerisation of ethylene initiated by organic peroxides with high productivity

A process for the preparation of expandable polystyrene including the following steps: i&#xb0;) heating an aqueous suspension including styrene monomer and at least one organic peroxide initiator of formula (I) 1-alkoxy-1-t-alkylperoxycyclohexane in which the alkoxy group contains 1 to 4 carbon atoms, the t-alkyl group contains 4 to 12 carbon atoms, and the cyclohexane ring may optionally be substituted with 1 to 3 alkyl groups each, independently having 1 to 3 carbon atoms, at a temperature ranging from 100&#xb0; C. to 120&#xb0; C., ii&#xb0;) adding a blowing agent selected from the group of alkanes having from 4 to 6 carbon atoms and mixtures thereof. Also, an expandable polystyrene obtainable according to such a process and to insulation parts and packaging including such an expandable polystyrene.

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Saint Genis Laval, France

Pascal Nicol