Study of the crystal structure of P(HBA/HNA)/PET blend fibers

The crystal structure of p-hydroxybenzoate/2-hydroxy-6-naphthoic acid copol yester [P(HBA/HNA)]/poly(ethylene terephthalate) (PET) blend (ACPET) fiber was studied with wide-angle X-ray diffraction and differential scanning cal orimetry. The results showed that crystallites of P(HBA/HNA) and PET were f ormed in ACPET fibers; that is, some crystallites of ACPET fiber were compo sed of PET chains, and others were composed of P(HBA/HNA) chains. The therm al behaviors of the crystals of each component in the blend fiber were diff erent from those of each corresponding pure component. For the fibers heat- treated at 300 and 350 degreesC, the degree of supercooling of P(HBA/HNA) s egments in the blend fibers was the same as that of P(HBA/HNA) fiber, but t he degree of supercooling of PET in the blend fibers was distinctly higher than that of pure PET fibers. Evidently, the aforementioned changes were at tributable to the blending of PET with P(HBA/HNA). (C) 2002 John Wiley & So ns, Inc.