NMR studies on the microstructure of copolymers of 1.3‐dioxolane and 1.3.5‐trioxane

The sequence distributions of the formal (OCH2) and ethylene oxide (OCH2CH2) units in copolymers of 1.3‐dioxolane (DOL) and 1.3.5‐trioxane (TOX) prepared under various polymerization conditions were determined by NMR. The results can be largely explained by a random copolymerization process including depolymerization, in which DOL is kinetically more reactive, but its incorporation is thermodynamically less favourable than that of TOX. However, in the later stages of the reactions the microstructure of the copolymer changes to give longer polyoxymethylene sequences, which produces very complicated thermodynamic problems.