PHASE STATES AND TRANSITIONS IN MESOPHASE POLY-BIS-PENTAFLUOROPROPOXYPHOSPHAZENE

The structure of poly-bis-pentafluoropropoxyphosphazene was studied by X-ray diffraction and differential scanning calorimetry in a wide ran ge of temperatures. At approximately 45-degrees-C, the polymer under i nvestigation exhibits a crystal-crystal type polymorphic transition, a nd at 90-degrees-C, a transition to mesophase. Compared to poly-bis-tr ifluoroetoxyphosphazene, the temperature of the mesophase-isotropic me lt transition increased to 310-degrees-C. The temperature interval, in which the mesophase is observed is more than 200-degrees-C for the po lymer studied. The structure of the mesophase is that of condis-crysta l, i.e., with positional order in a plane perpendicular to the macromo lecular axis, long-range orientational ordering of macromolecular posi tions, and short-range order (absence of periodicity) along the axes o f conformationally disordered chains.