The Physical Properties of Wool Fibers at Various Regains

Abstract

At relative humidities ( p/p0) between 5% and 90% the force ft at time t acting on a a wool fiber at fixed extension in the yield region is given by ft = [a - b ( p/p0)]ϕ ( t). Here a and b are quantities independent of humidity and time, while ϕ( t) is a function of time only and approximately linear with the logarithm of time. A model consisting of a network of bonds with various energy barriers to breakdown is proposed to explain the above relationship between force and time. Further, this model is applied to explain the mechanism of recovery from cohesive set. The role of water in bond breakdown and the effect of the mobility of the water are discussed with reference to the mechanisms of relaxation and recovery.