ABSTRACT

The kinetics of propagation for styrene and diene monomers in hydrocarbon solvents with lithium as the counterion is complicated by the association of the chain end active centers [1-3], analogous to the kinetic effects of initiator association discussed in Chapter 6. However, the kinetics of propagation can be investigated independently of the initiation event and this simplifies the analysis relative to the complexities involved in delineating the kinetics of the initiation reactions using alkyllithium initiators, in which initiation and propagation occur simultaneously (see Chapter 6). Obviously, however, it is essential to ensure that the initiator has been completely consumed before propagation kinetics is investigated. The complete consumption of the initiator requires rather large amounts of monomer for less efficient alkyllithium initiators in hexane or cyclohexane.