End-groups in polymers of 2-vinylnaphthalene and 4-vinylbiphenyl,prepared by polymerisations initiated by azobis(isobutyronitrile)

Polymerisations of 2-vinylnaphthalene and 4-vinylbiphenyl and copolymerisations of these monomers with methyl methacrylate have been initiated by azobis(isobutyronitrile) enriched in its methyl groups with carbon-13. The environments of (CH₃)₂C(CN)- end-groups in the copolymers have been examined by ¹³C nuclear magnetic resonance. It has been concluded that both aromatic monomers are more than twice as reactive as methyl methacrylate towards the primary radical.