Studies in Polyester Fiber Morphology and Related Dyeing and Finishing Properties by the Critical Dissolution Time (CDT) Technique

Abstract

Critical Dissolution Time (CDT) of polyester yarn in phenol or phenol/tetrachloroethane (TCE) mixtures was found to be an extremely sensitive technique for measuring fiber crystallinity and for detecting small morphological differences between untextured fibers and differences due to heat treatment. Pure phenol at 60°C is quite suitable foi measuring differences in fiber crystallinity due to heat treatment, while phenol/ TCE 1 :3 at 25°C amplifies the differences between yarns before heat treatment. The effect of phenol/TCE ratio was studied and an increase in phenol percent in the mixture decreases the CDT. Log CDT was found to have a linear relationship with fiber density and dye adsorption. CDT technique was used to monitor uniformity of untextured and textured yarn.