SOME ASPECTS OF ANIONIC BUTADIENE COPOLYMERIZATION

The relationship between ideal copolymerization behavior and the natur e of reactive species in butyllithium (n-BuLi) initiated anionic copol ymerization of styrene (St)- butadiene (Bd) in nonpolar solvent has be en discussed. The monomer reactivity ratios (m.r.r.) for various react ive species were evaluated by kinetic study and statistical approach ( using C-13 NMR data) in St-Bd anionic copolymerization system with THF as polar additive. The Markovian mechanisms for different propagating reactions in this complex copolymerizing system have been postulated. Furthermore, ''pseudo'' zero order Markovian mechnism could be sophis ticatedly established in the n-BuLi/tertiary amyloxy potassium (t-AmOK )/THF initiated St-Bd copolymerization system, provided that the appar ent rate constants of both monomers are equal. Thus, by adjusting the ratio of K/Li and THF/Li, copolymers with composition almost identical to the ratio of initial monomer feed composition at different stages of conversion could be obtained.