Contributions to the Mechanism of Isobutene Polymerization. I. Theory of Allylic Termination and Kinetic Considerations

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Abstract
Theories dealing with the problem of termination in ionic polymerizations by hydride transfer coupled with allylic stabilization have been examined and extended. It is postulated that cationic polymerizations in general terminate with the irreversible destruction of growing ions by the following mechanism: A kinetic model is developed and used to define an empirical poison coefficient (P.C.) and transfer coefficient (T.C.), characterizing a material as to its effectiveness in kinetic chain termination and chain breaking, respectively. Experiments indicate that allylic self-termination in unhibited polymerizations of isobutene with AlCl3 catalyst, although undoubtedly present, is not an important molecular weight determining event.