Some kinetic effects in the polymerization of 1,3,5‐trioxane

The cationic polymerization of 1,3,5‐trioxane in methylene dichloride with boron trifluoride, producing polyoxymethylene, was investigated. An ionogenic cocatalyst is not required in this polymerization. During the induction period, initially formed, short polyoxymethylene chains depolymerize to formaldehyde until a constant equilibrium concentration of formaldehyde is reached. This concentration is equal to the ceiling concentration of formaldehyde in cationic polymerization under the conditions chosen for the experiments. The nonstationary state and the strong acceleration of the polymerization of trioxane are due mainly to the lack of an effective kinetic termination reaction. Thus the concentration of growing polyoxymethylene cations increases with time.