An Automated Water Vapor Diffusion Test Method for Fabrics, Laminates, and Films

Abstract

An automated apparatus has been developed to measure the transport of water vapor through coated and uncoated fabrics, fabric laminates, thin foams, and solid films under a variety of conditions. The apparatus is more convenient to use than the traditional test methods for textiles and clothing materials; it allows one to use a wider variety of test conditions to investigate the concentration-dependent and nonlinear transport behavior of many of the semipermeable membrane laminates that are now available. The dynamic moisture permeation cell (DMPS) has been auto mated to permit multiple setpoint testing under computer control and to facilitate in vestigation of transient phenomena. Results generated with the DMPC are in agree ment with and of comparable accuracy to those from the ISO 11092 (sweating guarded hot plate) method of measuring water vapor permeability.

Effect of Temperature on Water Vapor Transport Through Polymer Membrane Laminates

“…The Dynamic Moisture Permeation Cell (DMPC) [7][8][9], is an automated device that can test the mass transport properties of very small pieces of woven and nonwoven fabrics, membranes, and foams. The apparatus is more convenient to use than the traditional test methods for textiles and clothing materials, and allows one to use a wider variety of test conditions to investigate concentration-dependent and nonlinear transport behavior of the many types of semipermeable membrane laminates which are now commercially available.…”

“…plus the boundary layer resistance (R b ), as defined in equation (4). In this report we present the combined resistances as a single value, but procedures exist for separately determining the intrinsic material mass transfer and boundary layer resistances [7,8]. The results show the expected increase in water transport with humidity for the two materials (B and C) with a hygroscopic polymer component.…”

“…The DMPC, when operated in the pure vapor diffusion mode (no pressure drop across the sample) is capable of showing this concentration-dependent transport behavior [7][8][9][10].…”

“…The analogy is to the water vapor sorption isotherm, which is the equilibrium water content of a hygroscopic polymer as a function of relative humidity. The mean relative humidity has proven to be useful in showing the mass transport behavior in terms of concentration dependence of the permeability coefficient [4,7,8]. Figure 4 shows the measured water vapor diffusion resistance of the three materials using the setpoints of Table 1.…”

Nanofibers for High Efficiency Filtration

“…Air and vapor transport properties of electrospun Nano stringy mats have been measured utilizing a device called dynamic dampness vapor penetration cell (DMPC) [21,22]. This gadget has been intended to gauge both the dampness vapor transport and the air porousness (convective gas stream) of constant movies, textures, covered materials and open froths and battings.…”