Elastic response of copolyether-ester fiber on its phase morphology under different heat-treatment condition

In order to verify the elastic response of copolyether-ester (PEE) fibers on their phase morphology and structure, the PEE fibers based on poly(butylene terephthalate) (PBT) as hard segments and poly(terramethylene glycol) (PTMG) as soft segments were prepared by melt spinning, the as-spun fibers were then heat-drawn and heat-set at different conditions. From the analysis of the mechanical properties, it is shown that the tenacity as well as elastic recovery of the fibers increased with the increasing heat-draw ratios, the elongation at break decreased. The morphological and structural were evaluated by small angle X-ray scattering (SAXS), wide angle X-ray scattering (WAXS) and birefringence. When the melt-spun PEE fibers were heat-drawn, higher crystallinity and orientation, larger size of lamellae structure was formed within the fibers, it is also much easier to form higher phase separation. This structure will contribute to better elastic performances of PEE fibers.