RING-OPENING POLYMERIZATION OF BICYCLIC AND SPIRO COMPOUNDS - REACTIVITIES AND POLYMERIZATION MECHANISMS

Ring-opening polymerization of heterobicyclic compounds, such as bicyclic acetals, lactones, lactams, and orthoesters provides a convenient and effective route to designing functional polymers containing heterocycles in their main chains. Polycondensation and polyaddition also give some of these polymers, but ring-opening polymerization has the advantage of producing polymers not only high in molecular weight but also sterochemically regulated. The reactivity of bicyclic monomers varies over a wide range, and in addition, highly strained monomers are often ring-opened by two or more different ways. In some cases, ring-opening polymerization accompanies isomerization. These features complicate the ring-opening polymerization of bicyclic monomers. The present article reviews recent advances in ring-opening polymerization of selected bicyclic and spiro compounds, focusing on the structure-reactivity relationships and the polymerization mechanisms.