Styrene dibromide-2-14C as a photoinitiator in the polymerization of styrene

Abstract

The polymerization of styrene, photoinitiated with small amounts of (1,2-dibromoethyl)-benzene (styrene dibromide) has been studied at 30°C. The initiator was labelled with ¹⁴C and measurements were made of the activity in the initiator, monomer and polymer during the course of polymerization. Labelling became incorporated in the monomer by an exchange reaction involving the transfer of bromine from a labelled bromostyryl radical to unlabelled monomer; the rate constant for this reaction had approximately the same magnitude as that for the addition of bromostyryl radicals to styrene in a normal propagation step.