Water Vapor Permeability of Organic Films

Abstract

An apparatus for a rapid, precise, and reproducible determination of water vapor permeability is described. It seems that two factors, diffusion velocity and solubility, together determine the vapor per-

Some Moisture Relations of Wool and Several Synthetic Fibers and Blends

“…Analysis of the intrafiber diffusion problem may be treated roughly as diffusion through a film. Doty, Aiken, and Mark [5], Hauser and McLaren [12~, and Singleton and Johnson [28] have studied TABLE X the water vapor permeability of films of nylon, cellophane, acrylonitrile copolymer, and other polymeric materials. Information on the diffusion behavior of wool and horn keratin has been given by King [14,15,16], Baxter [ 1 ] , and Peirce, Rees, and Ogden [21].…”

“…The drying mechanism is believed to depend upon vapor diffusion from the atmospheric &dquo;well&dquo; within the fabric to its periphery, and thence through a boundary film, where mass-energy transfer occurs. 5. Towards the end of drying, the water retained in interfiber capillaries is believed to be replenishing the atmospheric &dquo;well&dquo; by evaporation from both concave liquid films and from saturated fiber surfaces.…”

Water Permeability of Coating Films Using a Radioisotope Tracer Technique

“…The coefficient of variation was 22.87%, which indicates a somewhat larger fluctuation of the permeability constant. The constant appeared to increase with an increase in temperature as seen in Table 4. 15 The results of the above experiments differ from those of other researchers 17 who have stated that the permeability as much as doubled for a 10 o C rise in temperature. Since the permeability, P r , is proportional to the product of solubility, S, and the diffusion constant, D, as stated earlier in Equation 1, the effect of temperature on permeability is presumably twofold.…”

Effect of High Hydrostatic Pressure on the Permeability of Elastomers to Water

“…Permeability Measurements at Low Water Vapor Pressure, The apparatus and procedure used were similar to those of Doti, Aiken and Màik (20). Thin membranes of butyl rubber or polyurethane were subjected to vapor pressures of 5.8 and 17.5 mm on the ingoing side and the pressure increase in the evacuated receiving section (the volume of which was about 6 liters) was followed for 1-2 weeks for butyl rubber and for 24 hours for polyurethane , The permeabilit , was determined from the slopes of the steady-state permeation rates -…”