Polymer Synthesis by Cationic Polymerization

MITSUO SAWAMOTO Kyoto University, Kyoto, Japan 

When one looks at a polymer chain, one will soon realize that there are a number of structural factors that should or may be controlled in syntheses (Fig. 1). These factors may include (1) molecular weight (chain length) (2) molecular weight distribution (MWD) (3) end group (4) pendant group (5) sequence (the arrangement of constitutional repeat units 

In controlled polymer synthesis, in addition, it is particularly important that the control herein implies not only the simple regulation of molecular weights, MWD, and other structural factors but also the precise introduction of functional groups into specific positions of polymers with well-defined architectures. Namely, the control of one or more of these structural factors, then, leads to a variety of polymers of synthetic interest, as some of them illustrated schematically in Fig. 2  

Polymers e-g may also be called collectively as polymers with controlled spatial shapes amphiphilic polymers (h) may include block, star-shaped, and graft polymers covered in classes b, e, and f. Comparison of Figs. 1 and 2 also tells us that, unlike the anionic and coordination (Zieglar-Natta) counterparts, cationic polymerization still fails to provide general methods to control the steric structures of polymers, although the first indication 

This chapter presents an updated overview of the current status of the controlled polymer syntheses via the modem generation of cationic polymerizations that are mostly living or controlled what and how one can design and eventually synthesize novel polymers with well-defined structures and functionalities. Thus, the following sections are devoted to each of these classes of polymers (Fig. 2), with emphasis on the general methodologies and specific examples. The last section (Section VII) briefly covers the experimental procedures in living cationic polymerization and related polymer synthesis. 

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Higashimura, T. and Sawamolo, M Living Polymerization and Selective Dimerization Two Extremes of the Polymer Synthesis by Cationic Polymerization. Vol. 62, pp. 49-94. 

Sawamoto, M., Prog. Polym. Sci., 16, 111 (1991) Controlled Polymer Synthesis by Cationic Polymerization, Chap. 5 in Cationic Polymerizations Mechanisms, Synthesis, and Applications,... 

Living Polymerization and Selective Dimerization Two Extremes of the Polymer Synthesis by Cationic Polymerization... 

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