Variations in the Equilibrium Weight of Wool at Zero Humidity

Abstract

The equilibrium weight of a wool sample obtained on desorption in vacuo is de pendent on the previous treatment of the sample with respect to water. Exposure to < 5% RH has no effect on the subsequent equilibrium weight in vacuo, but exposure to intermediate relative humiclities causes an increased equilibrium weight in vacuo on subsequent desorption. The maximum rate of increase occurs on exposure to approxi mately 50% RH. Exposure to high relative humidities (near 100%) does not cause an increase in the subsequent equilibrium weight in vacuo. Initially the increase of equilibrium weight in vacuo is linearly dependent on the time of exposure to a particular relative humidity. Increases are less marked at higher temperatures (> 65° C.). Increases of the equilibrium weight in vacuo can be removed by saturation with liquid water or water vapor prior to desorption.