Thermal Stress Analysis of Textile Yarns

Abstract

The technique of thermal stress analysis is discussed in terms of basic yarn mechanical properties, particularly stress relaxation, and in terms of fundamental concepts of fiber fine structure. Examples of stress-temperature data obtained by this technique are given for as-spun, drawn, and textured yarns from polyester, polypropylene, and nylon 66. Several process variables are shown to affect significantly the stress-temperature “fingerprint” of a yarn, including, for as-spun yarns: orientation, ageing, and quenching; for drawn yarns: draw ratio and drawing temperature; and for textured yarns: texturing temperature, overfeed, and dyeing conditions.