The transport properties of polymer membrane-fabric composites

Breathable waterproof fabrics used in this study were prepared by polyurethane coating and polytetrafluoroethylene (PTFE) laminating processes. Outer garments manufactured from these materials can improve wearer comfort by increasing the transport properties of the fabrics. Water vapor permeability, water resistance, water repellency, air permeability, and the other characteristics were measured to evaluate the changes of transport properties with various finishing methods. In the case of the coated fabrics, wet coating A type had high water vapor permeability and low waterproof value, but dry coating A type showed opposite results. Air permeability at low pressure and airflow rate with differential pressure up to 350 kPa were different according to finishing methods. Significant differences in transport properties appeared as the coating methods or amounts of coating solution added to base fabrics were changed. Water vapor permeability and air permeability decreased, and water resistance increased with the amount of coating dope. On the other hand, the transport properties of laminated fabrics were relatively uniform regardless of two or three layers although some tactile properties might have been changed with laminated layers. (C) 2001 Kluwer Academic Publishers.