Internal Friction in Copolymer Vinylidenefluoride with Trifluoroethylene at Ferroelectric Phase Transition

Temperature dependences of internal friction Q–1, obtained at different heating rates of a copolymer VDF/TrFE (75/25) sample, are studied in the temperature range of 290–420 K at a frequency f ≈ 16 Hz. It is shown that the maximum of Q–1 observed in the vicinity of the ferroelectric phase transition (Tc = 393 K) is related to the motion of interphase boundaries and can be described within the low-frequency fluctuation mechanism of internal friction. The diffusion parameter σ of the ferroelectric phase transition is determined. The obtained σ value significantly exceeds the value that is due to possible microinhomogeneity of the chemical composition.