ABSTRACT
COLEEN PUGH The University of Michigan, Ann Arbor, Michigan
I. INTRODUCTION
Because a polymerization comprises several elementary reactions, the full mechanistic description of cationic polymerizations of alkenes must discuss the mechanisms of initiation, propagation, transfer, termination, and other reactions such as isomerization and rearrangements. These ele mentary reactions correspond to generation of active sites, monomer con sumption, transfer of activity from one chain end to a transfer agent such as monomer or counterion, and termination of the kinetic chain, respec tively. Carbenium ions are involved in nearly all of these reactions and therefore will be discussed first. This discussion supplements the general information provided in Chapter 2, which is devoted to reactions of carbe nium ions with various nucleophiles. The vast mechanistic information provided by living/controlled carbocationic polymerizations is covered in Chapter 4 and will not be discussed here. Our discussion focuses on sys tems which often do not provide well-defined polymers because of slow initiation, transfer and/or termination. Nevertheless, analysis of the chem istry and kinetics of these elementary reactions has elucidated the advan tages and disadvantages of various initiating systems, which has subse quently led to the development of new “living” systems for the synthesis of well-defined polymers.
