Properties of Apparel Wools: VIII. The Aging of Worsted Yarn

Mechanical properties derived from the force-extension curve, and including tensile recovery, have been measured for single strands of steamed worsted yarn throughout their aging at 65% R.H. and 70°F. None of these properties appears to change significantly throughout an aging period of several months. Measurements on single strands of unsteamed yarn which are permitted to untwist prior to test indicate a progressive change in physical properties with time of aging. This is caused by a slow setting-in of the twist similar to that provided rapidly by a steaming treatment.