Studies on Sorption of Solubilized Water by Textile Fibers in Nonaqueous Solutions. I.

Abstract

The moisture regain of textile fibers and the water content in solution equilibrated together with then were determined in the presence of various amounts of water solubilized by 0.1M Aerosol OT in perchloroethylene at 10°C, 20°C and 30°C. Simultaneously, the vapor pressure of solubilized water was measured at each temperature. Rayon, wool, nylon and acryl were used as test fabrics.The differential heat of absorption of water vapor (ΔHV) on the fabrics was calculated from the slope of linear plots of logarithm of the vapor pressure against the reciprocal of the absolute tempera-ture at given regains. ΔHV decreased with increase of moisture regain of the fabrics and with increase of solvent relative humidity in the solution. When the fabric and solution were in equilibrium with atmosphere, ΔHV was explained by the sum of the heat of solubilization (ΔHS) and the heat of solvation (ΔHH) of water. The decrease in free energy and the entropy change accompanying the absorption of water on the fabrics were also calculated approximately from the present data. It was concluded that the water was held by the fabrics in two different states; i.e., bound water and free water, near-by 75% solvent relative humidity in nonaqueous solution.