Effect of spin orientation on drawing of wet-spun fibers

Abstract

A previous study has shown that the draw stress of wet-spun acrylic fibers is affected by the orientation acquired in the spin bath, and a tentative mathematical treatment was proposed which employs an analogy with two-stage drawing. In this picture, the spin bath orientation is characterized by an effective draw ratio ℛs, the orientation draw is characterized by ℛ, and the total draw ratio ℛt equals ℛℛs. This concept is developed more extensively in this paper. New data are presented on both acrylic and modacrylic fibers which support the validity of this treatment and also demonstrate how spin orientation is correlated with the take-up speed/free velocity ratio. Absolute values for the effective spin orientation are calculated. Results from round spinneret holes and one-slot hole are discussed with observations on shape retention.