Orientational Phenomena in Poly[Bis-(2,2,3,3,3-Pentafluoropropoxy)-Phosphazene] Mesophase

Abstract

The thermotropic behavior and morphology of poly[bis-(2,2,3,3,3-pentafluoropropoxy)phosphazene] (PPPh) have been investigated by various methods such as: differential scanning calorimetry, scanning electron microscopy and X-ray diffraction. It was shown that a poiymer is able to exist in a four phases. A wide-angle X-ray temperature analysis indicates a monoclinic crystalline form for the first flow temperature) phase, the orthorhombic crystalline modification for the second one and the two-dimensional pseudohexagonal mesophase lattice for the mesomorphic state followed by the isotropic melt. Transition from the crystalline into the mesophase state in the range 85–100°C is observed. PPPh macromolecules in the mesomorphic state are found to be oriented in the extrusion direction.

Key Words:

• Mesophase
• X-ray diffraction
• polymer extrudates
• fluoroalkoxy side chain
• phase transitions
• crystalline forms.