Electrical properties of polytrifluoroethylene as a polyphase dielectric

Liquid and plastic polytrifluoromonochloroethylene polymers exhibit similar electrical behavior as a function of temperature and frequency. As the temperature is lowered, one passes from a single phase (either solid or liquid depending on average molecular weight) to a two-phase state characterized by the appearance of crystallites in the material. The temperature at which crystals appear depends on the average molecular weight of the polymer and is governed by the solubility of the longer chain material in the shorter chain length “mother liquor” ranging from ca. 200°C for the plastic material to −10°C for a liquid sample. In each case the appearance of the crystalline phase is accompanied by a sharp rise in the dielectric constant to a peak value governed by the volume percent of crystals. There appears to be two distinct relaxation processes involved: (1) a dipole orientation of the long chain rotator in the solid or crystalline phase and (2) a rotation of the dipoles in the liquid or glassy (depending on the temperature) non-crystalline phase. Although the loss factor (″) maxima occur at markedly different temperatures (for a given frequency), the activation energies derived from the data are the same.