REVERSIBLE CRYSTAL DEFORMATION OF POLY(TETRAMETHYLENE TEREPHTHALATE) SEGMENTS IN SEMICRYSTALLINE SEGMENTED POLY(ETHER ESTER) THERMOPLASTIC ELASTOMERS

Wide-angle X-ray scattering (WAXS) patterns of segmented poly(ether es ter) fibers, which were made from poly(tetramethylene glycol) (PTMG) a nd poly(tetramethylene terephthalate) (PTMT), under tensile stress wer e studied to clarify the effect of the amorphous region on reversible crystal deformation of PTMT crystallites in the copolymers. The transi tion between the alpha and beta crystal phases was observed around 800 Kg/cm(2) in tensile stress with various copolymers. The transition wa s not observed in PTMG rich copolymers in which the amorphous region w as too soft to bear this level of tensile stress.