Effects of Preconditioning Humidity on the Equilibrium Regain of Various Fibers, in the Standard Atmosphere for Testing

Abstract

The range of relative humidity from 5% to 25% has been found satisfactory for preconditioning cotton, wool, rayon, and nylon prior to bringing specimens to moisture equilibrium for testing in the standard atmosphere. The data were obtained for ASTM Committee D-13 on textiles. Part of the data reported here was used by the American delegates at the meeting of the ISO Technical Committee 38 on Textiles in London, Eng land, May 1960. Based in part on the data presented, ISO/TC 38 has now recommended preconditioning in an atmosphere of 10% to 25% RH [3], in place of the earlier recom mendation, viz., an atmosphere having a relative humidity below 10%. Preconditioning is carried out at temperatures below 50° C in both cases.

Sorption of Water Vapor by Keratin

“…Increased values of water content a r e obtained following extended periods of conditioning at humidities below the humidity of measurement, and such experimental conditions a r e generally avoided [126]. The good agreement between adsorption isotherms obtained by different workers does not extend to desorption isotherms.…”