The paper describes a method by which two different but important aspects of blended yarn structures could be studied together by a common procedure and set of parameters. These two aspects are: fiber helix migration, the importance of the study of which has been generally overlooked in blended yarns, and preferential radial migration. The present work is largely a theoretical attempt to relate a fiber helix migration parameter, the mean fiber position [Formula: see text], with a preferential radial migration parameter, the linear migration index V. The latter is a new parameter that is introduced in this paper, and although quite similar to Hamilton's migration index M in its general properties, it characterizes the preferential radial migration on a linear scale and bears, under uniform packing conditions, an exact and a simple relationship with [Formula: see text]. An appendix included at the end gives the treatment relating [Formula: see text]with M. The results of a small experiment carried out on a binary blend, 50/50 by weight of 3- and 6-denier, 21/2-in. staple, Kodel® polyester fibers, are also described. These provided a limited but useful means of checking the theoretical relations.
STUDIES ON THE STRUCTURE OF BLENDED YARN