Abstract: Thermal insulation packages (10) that are porous, air permeable, waterproof water vapor permeable, durable, and conformable are provided. The insulation packages include an insulation material (40) that is fully encompassed by at least one expanded polytetrafluoroethylene (ePTFE) membrane (20, 30). Two or more thermal insulation packages may be interconnected by sealed regions (50) to form an insulation construct. The thermal insulation packages and constructs may be used as inserts for garments or other articles.

Abstract: A method and apparatus for testing wearing apparel that defines an enclosure for moisture vapor transmission. Thin, flexible, waterproof liners which have a high permeability to moisture vapor are inserted into the interior of the apparel and filled with water. The water may be heated to simulate body temperatures and to produce higher concentrations of moisture vapor inside the apparel article. The amount of moisture transferred to the external environment of the apparel article, as well as the amount of moisture absorbed and condensed in the apparel article itself, can be measured by the weight differences which occur over a test period. The method is non-destructive and suitable for quality control, as well as for new product design.

Abstract: A membrane distillation module is provided with a thin, flexible microporous membrane positioned against an impermeable condensor sheet that is stiffer in bending than the membrane. Distillate vapor diffuses through the membrane from the hot feed flowing rapidly past the membrane, and condenses and collects between, and in intimate contact with, the membrane and the condensor sheet. The condensed distillate is stripped by forces exerted by the hot feed acting on the distillate across the membrane, and flows toward a distillate outlet located in the downstream direction of the hot feed flow. Cold feed flows past the condensor sheet in the counter direction to that of the hot feed for absorbing the latent heat of condensation, and is subsequently additionally heated and introduced into the hot feed channel. Expanded microporous polytetrafluoroethylene (PTFE) is the preferred membrane material, and a spiral-wound assembly is the preferred configuration.

Abstract: A waterproof article for use in, for example, protective clothing. The article prevents liquid water from penetrating through to undergarments while at the same time permitting moisture vapor such as perspiration to pass out through the article. The article is thus both breathable and waterproof. The article is layered: a microporous hydrophobic outer layer which permits the passage of moisture vapor but resists penetration by liquid water at pressures up to about 345 Kn/m.sup.2 ; a hyrophilic inner layer permitting the transfer of moisture vapor but preventing surface tension lowering agents such as those contained in perspiration and/or body oils from reaching the hydrophobic layer.

Abstract: This invention provides a tetrafluoroethylene polymer in a porous form which has an amorphous content exceeding about 5% and which has a micro-structure characterized by nodes interconnected by fibrils. The material has high porosity and high strength. It can be used to produce all kinds of shaped articles such as films, tubes, rods, and continuous filaments. Laminations can be employed and impregnation and bonding can readily be used to produce a large variety of articles. Compressed articles of very high strength can also be produced from these porous forms.

Abstract: This invention provides a tetrafluoroethylene polymer in a porous form which has an amorphous content exceeding about 5% and which has a micro-structure characterized by nodes interconnected by fibrils. The material has high porosity and high strength. It can be used to produce all kinds of shaped articles such as films, tubes, rods, and continuous filaments. Laminations can be employed and impregnation and bonding can readily be used to produce a large variety of articles. Compressed articles of very high strength can also be produced from these porous forms.

Abstract: This invention provides a tetrafluoroethylene polymer in a porous form which has an amorphous content exceeding about 5% and which has a micro-structure characterized by nodes interconnected by fibrils. The material has high porosity and high strength. It can be used to produce all kinds of shaped articles such as films, tubes, rods, and continuous filaments. Laminations can be employed and impregnation and bonding can readily be used to produce a large variety of articles. Compressed articles of very high strength can also be produced from these porous forms.