Poly(alkylene oxide) ionomers. IV. Polyoxymethylene copolymers with carboxylate side groups: Calorimetric, dynamic mechanical and dielectric properties

Copolymers and terpolymers of trioxane with 1,3‐dioxolane and/or ethyl glycidate prepared by cationic ring opening polymerization were converted to the corresponding salts of monovalent cations and their free acid analogs. Calorimetric studies of these copolymers furnished evidence for the incorporation of oxyethylene units into the crystalline regions of the trioxane‐dioxolane copolymers. Dynamic mechanical and dielectric relaxation spectra of the ester substituted polyoxymethylenes or their polymeric alkali salts exhibited the three relaxations characteristic for polyoxymethylene, labeled α, β and γ in order of decreasing temperature. Two additional peaks, α′ and β′, were also found which are ascribed, respectively, to motions of carbonyl ester side groups in the trioxane‐ethyl glycidate‐1,3‐dioxolane terpolymers. The prominent β peak, mechanically active but dielectrically inactive in the trioxane‐1,3‐dioxolane copolymers, was assigned to rocking motions of rotational isomers containing the oxyethylene unit.