A method is described for measuring the water vapor resistance of textiles under variable conditions of relative humidity (RH). It consists basically of varying the position of the sample in an air gap between a wet and a dry surface while keeping all other conditions constant. The resistance is determined by the rate of water loss from the apparatus and the temperature of the water. The results for microporous PTFE and polyurethane films show little variation with RH, but fabrics and films with hydrophilic coatings added show strong variations, the resistance increasing substan tially with decreasing RH.
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References
1.
Farnworth, B. , and Dolhan, P.A., An Apparatus to Measure the Water Vapour Resistance of Textiles, J. Textile Inst. 75 (2), 142-145 (1984).
2.
Fourt, L., and Harris, M., Diffusion of Water Vapor through Textiles, Textile Res. J.17, 256-263 (1947).
3.
King, G., Trans. Faraday Soc.41 ( 1945), cited in W.E. Morton , and J.W.S. Hearle, "Physical Properties of Textile Fibres ," Heinemann, London, 1975.
4.
Lotens, W.A. , Improvement of the Construction of Protective Clothing for Better Wearability and Comfort, report of the Institute for Perception IZF 1986-26, Soesterberg, The Netherlands.
5.
Osczevski, R.J. , and Dolhan, P.A., Anomalous Diffusion in a Water Vapour Permeable, Waterproof Coating, Defence Research EstablishmentOttawa technical note 87-3 1987.
6.
Rouse, P.E., J. Am. Chem. Soc.69 ( 1947), cited in W.E. Morton , and J.W.S. Hearte, "Physical Properties of Textile Fibres ," Heinemann, London, 1975.
7.
van Beest, C.A. , and Wittgen, P.P.M.M., A Simple Apparatus to Measure Water Vapor Resistance of Textiles, Textile Res. J. 57 (9), 566-568 (1986).
