ZONE DRAWING AND MECHANICAL RELAXATION OF POLY(VINYLIDENE FLUORIDE)

Poly(vinylidene fluoride), PVF2, has been zone drawn to extensions up to 7 times. Well oriented β phase tapes are produced when the draw neck moved out of the hot zone, at extensions over six times and zone temperatures =<155°C. Other conditions give α phase tapes. The dynamic mechanical spectra of highly drawn PVF2 is exactly the same for both phases, with Tg at −25°C and a sharp rise in tan δ at 50°C. Isotropic α and β phase sheets gave different mechanical spectra, but with similar features at different strengths. As the isotropic sheets were prepared in very different ways, no specific features of the spectra could be assigned to the different phases. Copyright © 1990 John Wiley & Sons, Inc.