Trigonox® 42S is an efficient initiator for the ethylene polymerization under high pressure in both autoclave and tubular processes. To obtain a wide spectrum of polymerization temperatures, combinations with other peroxides are applied in practice. Depending on reaction conditions, Trigonox® 42S is active in the temperature range of 210-240°C. Trigonox® 42S can be used as initiator for the solution (co)polymerization of acrylates and methacrylates in the temperature range of 90-175°C, amongst others for the manufacture of coatings. Trigonox® 42S can also be applied as an initiator for the bulk and suspension (co)polymerization of acrylates and methacrylates in the temperature range of 90-130°C. Trigonox® 42S may be used for the (co)polymerization of styrene in the temperature range of 90-140°C.