Stress-induced crystalline phase transition in block copolymers of poly(tetramethylene terephthalate) and poly(tetramethylene oxide). II Phase transition and inhomogeneous deformation.

Abstract

The stress-induced solid-state phase transition in the uniaxially-oriented poly (tetramethylene terephthalate)-poly (tetramethylene oxide) block copolymers has been investigated at room temperature by X-ray diffraction and infrared and Raman spectroscopy. The phase transition in the hard crystalline region has been found to occur broadly over wide stress and strain region. The small-angle X-ray scattering measurement showed that, as the sample is stretched, a new meridional scattering is observed in addition to the original one, indicating a very heterogeneous structural deformation within the sample. The phenomenon has been considered to originate from the broad distribution of the hard segmental lengths in the multi-block copolymer samples.