Polyether synthesis: From activated or metal-free anionic ring-opening polymerization of epoxides to functionalization

The terminal grafting of poly(ethylene oxide) chains to silica surfaces

Following a short introduction and a brief discussion of thermodynamics of propagation, the kinetics and mechanisms of anionic polymerization are reviewed. The systems involving living polymers, a term introduced by this writer, are discussed in greater detail because the existence of various ionic species participating in polymerization was clearly revealed by their studies. Indeed, a large part of this review is concerned with the methods used in identification of these species and determination of their role in various polymerizing systems. The results of such studies are compared with those derived from investigations of radical-anions, carbanions and other ionic species.

Living Polymers and Mechanisms of Anionic Polymerization

Extensive studies of the mechanism and kinetics of the anionic polymerization of epoxides and episulfides have been reported during the last few decades, and they were reviewed quite recently by several authors.1–5 Most of the experiments were carried out with ethylene oxide (oxirane) and propylene sulfide (2-methylthiirane) because the living character of the polymerization of these two monomers, under specific conditions, has been well established;6, 7 propylene oxide (2-methyloxirane) polymerizes anionically with transfer to monomer, and poly(ethylene sulfide) is insoluble. In this chapter, the kinetics and mechanisms of the ring-opening reactions of epoxides and episulfides with nucleophilic initiators, as well as with the living ends during propagation, will be presented.

C.E.H. Bawn

Papers

Anionic polymerization of ethylene oxide in dimethyl sulphoxide

Anionic polymerization in dimethyl sulphoxide