The t-butylthiyl radical as initiator in vinylpolymerizations : Investigations into the initiation step by the aminoxyl trapping technique

Abstract

The reactions of t-butylthiyl radicals with methyl methacrylate, methacrylonitrile, vinylacetate and styrene were studied by using an aminoxyl radical scavenger. The product 4 (thiyl radical 2 trapped by the aminoxyl 1) was the main product in all monomers except styrene. Products formed by addition of the thiyl radical to the double bond of the monomer were observed in vinyl acetate, methacrylonitrile and methyl methacrylate. Surprisingly, in styrene no products arising from addition of thiyl radicals were observed. The ratio of the rate of addition of t-butyl thiyl radicals to monomer is: VA : MAN : MMA = 1 : 5 : 8.