Dielectric Constant and Conductance Changes in Wool Fibers Produced by Step Changes in the Relative Humidity

Abstract

The dielectric constant of single wool fibers has been measured at a frequency of 1592 cycles, sec and a temperature of 35° C for a range of relative humidities. Also the changes in dielectric constant that occur when the relative humidity surrounding single fibers is suddenly increased from zero have been examined as a function of time. The conductance of similar fibers has been measured under the same experimental conditions. There was an initial rise in the dielectric constant and conductance, followed by a , decrease to an equilibrium value. Both the dielectric constant and the conductance continued to change after an equilibrium water content had been reached. The impli cations of the results upon theories of the polarization and conductance of keratin are discussed, and the relationships between the electrical results and the shape of the absorption/time curves for the keratin-water system are examined. A practical consideration arising from the study is that transient effects (due to changes in the relative humidity) may cause inaccuracies when electrical methods are used for determining water content.