Ring‐Opening Polymerization

This chapter describes the polymerization of cyclic monomers through a ring-opening mechanism, with emphasis on the parameters that control polymer molecular weight. Many different types of monomers undergo ring-opening polymerization–cyclic ethers, lactones (cyclic esters), lactams (cyclic amides), cyclosiloxanes; cycloalkenes, N-carboxyanhydrides, cyclic sulfides, cyclotriphosphazenes, zwitterion polymerization, and various organometallic and inorganic monomers. Most, but not all, cyclic monomers undergo polymerization by both anionic and cationic initiators. Some monomers require special initiators. Some ring-opening polymerization proceed as living polymerizations. Polyamides, polyacetals, polysiloxanes, and specialty elastomers are among the commercial polymers produced by ring-opening polymerization.