Anionic Polymerization Initiation step:The initiator adds to the monomer to the form an anion. H、 CN CN Bu一C一C: Li butyllithium acrylonitrile stabilized anion Copyright2010 Pearson Prentioe Hall,Inc. Propagation step:Another molecule of monomer adds to the chain. T8 CN growing chain acrylonitrile elongated chain Copyright 2010 Pearson Prentice Hall.Inc. Alkene must have an electron-withdrawing group like C=O, C≡N,orNO2: The reaction is initiated by a Grignard or organolithium reagent. Chapter 26 10 Chapter 26 10 Anionic Polymerization ▪ Alkene must have an electron-withdrawing group like C═O, CN, or NO2 . ▪ The reaction is initiated by a Grignard or organolithium reagent