Hysteresis Effects Associated with the Adsorption and Desorption of Water by Woven Wool Fabrics

Changes have been examined in the lengths of four woven wool fabrics on adsorption and desorption of water. The lengths are greater on desorption than on adsorption, a trend that is opposite that previously reported for length differences at a given regain. The magnitudes of the length differences (at constant regain or relative humidity) are determined primarily by the levels of fabric hygral expansion. After extending the conditioning time from 24 hours to up to 14 days at a particular relative humidity, length and regain differences decreased, but the relationships between length and regain for both adsorption and desorption were unaffected. At a given relative humidity following desorption, lengths and regains were greater as the relative humidity from which desorption occurred was increased.