Rheo‐optical fourier‐transform infrared spectroscopy of polymers. 9. Stretching‐induced II(α)‐I(β) crystal phase transformation in poly(vinylidene fluoride)

Simultaneous Fourier‐transform infrared (FTIR) spectroscopic and stress‐strain measurements have been used to study the II(α)‐I(β) crystal phase transformation in poly(vinylidene fluoride) under tensile stress at variable temperature. From the experimental data it can be derived that in the investigated temperature interval from 348 to 423 K the drawing process is inhomogeneous and occurs via formation of a neck. The II(α)‐I(β) phase transformation is restricted to temperatures below 423 K and its onset is generally related to the formation of the neck.