Iodine‐initiated, solid‐state copolymerization of tetraoxane with 1,3‐dioxolane in the presence of methylal. IV. Fractional dissolution of copolymer

摘要

AbstractA fractional dissolution on the oxymethylene copolymer obtained by the iodine‐initiated, solid‐state copolymerization of the tetraoxane–1,3‐dioxolane‐methylal system has been carried out using a mixed solvent which consists of tetrachloroethane, phenol, and cyclohexanol. On the fractional dissolution, the oxymethylene copolymer was divided mainly into two parts: one was the copolymer containing a larger amount of ethylene oxide unit in its main chain and having lower molecular weight; the other was copolymer containing a smaller amount of ethylene oxide unit and having a higher molecular weight. It was reasonably concluded that in this copolymerization system, the reaction proceeds from the surface to the center of the tetraoxane crystal to give a divided copolymer due to the heterogeneous properties such as copolymer composition and molecul