RADICAL TERMINATION MECHANISMS IN BULK POLYMERIZATION

Abstract

The termination mechanism in the bulk polymerization of styrene and vinyl acetate initiated by α,α′-azobisisobutyronitrile has been investigated. C 14 -Labelled initiators were employed and activities of samples were determined by internal liquid scintillation counting. Measurements of fractionated and unfractionated polystyrene showed an average of 1.94 and 2.04 tagged fragments per molecule, respectively, and indicated termination by combination at 60 °C. For polyvinyl acetate 1.06 fragments were found per molecule, indicating termination by disproportionation at 60 °C.