SPHERULITIC CRYSTALLIZATION IN POLY(BIS(TRIFLUOROETHOXY)PHOSPHAZENE), PBFP

Spherulite formation in poly(bis(trifluoroethoxy)phosphazene) has been investigated from the melt and from solution over a relatively wide crystallization and annealing range. Three polymorphic forms and one mesoform is found in this polymer. Several of these crystal modifications coexist in amounts which depend upon the crystallization conditions. Microbeam X-ray analysis made within the spherulite shows that the unit cell left bracket a right bracket direction is along the spherulite radius while the left bracket c right bracket chain direction lies transverse to the spherulite radius. Moreover, below T(1) it has been established that the X-ray long period is invariant with annealing time and temperature, and above T(1) the periodicity disappears, or cannot be recorded. All transformations from the isotropic melt or the folded chain conformation must pass through the mesophase. All specimens are friable upon cooling below T(1), whereas the solution case spherulitic copolymer film is ductile here.