Orientation of Polyoxymethylene Obtained by Cationic Polymerization of Tetraoxane and Trioxane in Solid State

Abstract

The solid state polymerization of tetraoxane and trioxane catalyzed by BF₃, or BF₃O (C₂H₅) ₂ was discussed on the basis of an X-ray study. Polyoxymethylene produced from trioxane was highly oriented and showed highmelting point (188-190°C). On the other hand, degree of orientation and melting point (181-185°C) of polymersprepared from tetraoxane were not so high as those produced from trioxane. In the solid state polymerization oftrioxane, a highly oriented polymer was obtained at low conversion and at high temperature. In the polymerizationof tetraoxane, the orientation of polymer slightly decreased with increasing temperature and increasedwith increasing conversion. The degree of orientation and the amount of twin structure of polyoxymethylenewere explained in terms of the crystal structure of tetraoxane and trioxane.