Chain branching is not as common with anionic polymerization as it is with free-radical polymerization and cationic polymerization.
(a) Propose a mechanism for chain branching in the polymerization of acrylonitrile.
(b) Compare the relative stabilities of the intermediates in this mechanism with those you drew for chain branching in the cationic polymerization of styrene.
Explain why chain branching is less common in this anionic polymerization.