Annealing effects on molecular structures and physical properties of side-by-side conjugate fibers

Abstract

Poly(trimethylene terephthalate) (PTT)/poly(ethylene terephthalate) (PET) side-by-side conjugate fibers were heat-treated to investigate the effects of annealing on structure development and physical properties. The effects of annealing temperature and time were observed. Even though the drawn conjugate fibers were sufficiently drawn, X-ray profiles showed that the molecular orientation was insufficient. After annealing for more than 1 hour at 180°C, PET and PTT crystal structures developed sufficiently. Crimp contraction decreased from 29% to 22.6% by annealing due to the development of the crystalline structure of the annealed PTT part. Decrease in a shrinkage difference between PET and PTT leads to a decrease in crimp contraction. Thermal shrinkage was also reduced from 11.0% to 1.8% by annealing.