INTERACTION OF WATER VAPOR WITH PRISTINE E-GLASS FIBER.
Abstract
The surface of the E-glass fiber is subject to subtle chemical changes, as are all glass surfaces. An unmodified surface, pristine E-glass fiber was prepared directly from a melt of E-glass marbles. The experimental conditions were selected to measure adsorption on partially covered surfaces where the influence of surface groups can best be seen. The sample of E-glass fiber was selected so that the surface area was very much larger than the walls of the Pyrex container. The volumetric adsorption procedure employed for krypton was adapted for use with water vapor. Knowing the length, weight, and density of the pristine E-glass fiber, an independent value was determined for the cross-sectional area of adsorbed krypton at -195C. The adsorption and description of water vapor was followed between 90 and 150C, and simple Elovich kinetics were observed for times up to 2000 min. Adsorption isotherms for water vapor were calculated after the fractional decrease in pressure became < 0.01. The heat of adsorption for an estimated surface coverage of 0.4 was 7900 cal/mole; the corresponding heat of vaporization of water was 8000 cal/mole. The behavior of pristine E-glass fiber was compared with the behavior after treatments with liquid water. The complexity of a glass surface is obviously compounded after aqueous treatments, and the influence of this on gas adsorption is pronounced. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 31, 1968
- Accession Number
- AD0686377
Entities
People
- Victor R. Deitz
Organizations
- United States Naval Research Laboratory