Multinuclear NMR studies of end-groups in polymers—III. Search for abnormal end-groups derived from azoisobutyronitrile

Samples of azoisobutyronitrile (AIBN), labelled with deuterium and nitrogen-15, have been used to initiate polymerizations and copolymerizations of styrene and methyl methacrylate. As in the case of [¹³C]-AIBN, the chemical shift associated with an end-group labelled with a particular isotope depends upon the nature of the attached monomer unit but there is no evidence of more than one type of end-group.