Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Benzoyl peroxide labelled with carbon‐14 and tritium has been used for study of the end‐groups in copolymers of α‐methylstyrene (MST) with methyl methacrylate, in particular determination of the relative numbers of benzoate and phenyl end‐groups derived from the initiator. MST is found to be quite reactive towards the benzoyloxy radical. It is deduced that combination is the dominant mode of termination in the copolymerization, that transfer reactions are not important and that there is little abstraction of hydrogen from MST by the benzoyloxy radical.</jats:p>