ADSORPTION OF WATER ONTO POLYPROPYLENE FIBERS.

The purpose of the reported work was to examine the possibility of measuring adsorption isotherms of water on hydrophobic polymers by using a gas chromatographic method. Gas chromatographic measurement of retention of water on PP fibers yielded adsorption isotherms convex towards the pressure axis. The results were in good qualitative agreement with previously reported data for water adsorption onto hydrophobic surfaces. Treating the fibers in fuming nitric acid results in large increases in the amount of water adsorbed. Much further work is required in order to fully quantify the isotherms and to determine more precisely the nature of the active sites on the polymer surface. Nevertheless, gas chromatography is shown to be a method of obtaining reliable adsorption data in systems where the amount of adsorbed vapor is very low.