The polymerization of crystalline trioxane. IV. the spontaneous polymerization

The spontaneous transformation of trioxane crystals to crystalline, pseudomorphous polyoxymethylene is found to be a process of the type: A crys t → B cryst ' occurring in the surface regions of dry crystals only while these are in the act of a phase change, which may be either in integration or a disintegration. The morphology of the polymer is described and its bearing on the growth dynamics discussed. It is shown that the reaction, which can be effected reproducibly by zone-refining trioxane, cannot be understood in terms of initiation by chemical individuals and separate propagation of molecular chains. It must be a cooperative process involving many lattice planes synchronously, and is presumably closely connected with the electret character of crystalline trioxane.