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Ring-Opening Polymerizations of Cyclic Acetals

المؤلف:  A. Ravve

المصدر:  Principles of Polymer Chemistry

الجزء والصفحة:  273

2026-01-26

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Ring-Opening Polymerizations of Cyclic Acetals

The cationic polymerizations of cyclic acetals are different from the polymerizations of the rest of the cyclic ethers. The differences arise from great nucleophilicity of the cyclic ethers as compared to that of the acetals. In addition, cyclic ether monomers, like epirane, tetrahydrofuran, and oxepane, are stronger bases than their corresponding polymers. The opposite is tree of the acetals. As a result, in acetal polymerizations, active species like those of 1,3-dioxolane, may exist in equilibrium with the macroalkoxy carbon cations and tertiary oxonium ions [69]. By comparison, the active propagating species in the polymerizations of cyclic ethers, like tetrahydrofuran, are only tertiary oxonium ions. The properties of the equilibrium of the active species in acetal polymerizations depend very much upon polymerization conditions and upon the structures of the individual monomers.