Dynamics and evolution of structure in fiber extrusion

This paper gives a review of scientific advances in the understanding of th e mechanism of fiber structure development in the high-speed melt spinning process. Research in this field has been active since the late 1970s. Parti cular attention is paid to the molecular orientation and orientation-induce d crystallization occurring in the high-speed spinning process of poly(ethy lene terephthalate), polyamides, and some other types of polymers. Characte ristics of crystalline morphology developed in the spin line and evolution of structural variation in the cross-section of the fiber are also discusse d. On-line measurement of the spin line revealed that fiber structure devel opment is accompanied with neck-like deformation. Detailed behavior of the neck-like deformation such as diameter profile, necking temperature, and ne cking draw ratio are presented, and the relation between the neck-like defo rmation and the structure development is also discussed. (C) 2002 John Wile y & Sons, Inc.