Supermolecular Structure and Their Physical Properties of Poly (ethylene terephthalate) Fibers Spun at High Wind-up Speed

Abstract

An attempt was made to investigate the effect of wind-up speed on the supermolecular structure, physicalproperties and dyeability of poly (ethylene terephtalate) (PET) fibers. The wind-up speed was changed from2 to 9 km/min at a constant melt flow rate (series I) or a constant denier (series II). The supermolecularstructure of as-spun fibers was discussed on the basis of the experimental result as studied by interferencemicroscope, X-ray diffraction and differential scanning calorimetry (DSC). Stress-strain curves were analyzedto evaluate physical properties and dyeability was estimated from dye exhaustion-time curves of two differentdisperse dyes ; Diacelliton Fast Orange GL (molecular weight : 242) and Resolin Blue FBL (molecular weight : 349). The outer side of the fibers spun at wind-up speed beyond 5 km/min had larger crystallinity and larger orientaion of the molecular chain than the central part of the fibers. Both the crystallinity and the orientation of crystallites increase as increasing wind-up speed. The region corresponding to αa2 absorption belongsto a part of the amorphous region associated with facile diffusability of dye molecules.