The Physical Properties of Wool Fibers at Various Regains

Abstract

Watt and Kennett [11] have shown that water may be incorporated into the keratin structure by long exposure at relative humidities between 5% and 80%. This incor porated water is not removed on drying in vacuo and results in an increase of the "dry" weight of the wool fibers. Mechanical tests carried out on fibers containing incorporated water show an increased stiffness for relative humidities less than 60-70% over stiff ness measured at the same humidities after the incorporated water had been removed by saturation in liquid water. It is proposed that the water which is incorporated into the keratin structure and produces the "dry" weight increase becomes immobilized at intermediate relative humidities by increased strength of bonding of the water directly with the keratin structure. Saturation in liquid water reduces the amount of associa tion between any one molecule and the keratin structure. Drying rapidly from this state hence lowers the possibility of formation of strong, direct bonds between water and keratin.