Fabric hygroscopic

Hygroscopic materials, condensation of moisture, or tarry adhesive components possibly causing crusty caking or plugging of the fabric or requiring special additives... 

These absorb moisture, which then has to be carefully removed before the plastics can be fabricated into acceptable products (2,3). Low concentrations, as specified by the plastic supplier, can be achieved through efficient drying systems and properly handling the dried plastic prior to and during molding, extrusion, etc. (Figs. 7-24 and 7-25). When desired processor can have these hygroscopic plastics properly dried and shipped in sealed containers. 

As a metal, Pr is hygroscopic (adsorbs water) and tarnishes in the atmosphere. It will react with water to liberate hydrogen. It is soluble in acids and forms greenish salts, along with some other rare-earths. It is used to fabricate the electrodes for high-intensity lights. 

A saturated salt sensor is constructed with an absorbent fabric bobbin covered with a bililar winding of inert electrodes and coated with a dilute solution of lithium chloride. Lithium chloride tLiCI) is often used as the saturating salt because of its hygroscopic nature, which permits application in relative humidities between 11 and 100%. 

In addition to wool, other hygroscopic textile materials such as cotton and linen underwent a threefold increase in their specific heat at constant vapor pressure. The relatively high specific heats derived from equations in the study, which are considered to represent those incurred in actual use of the hygroscopic textiles, explain the well-known buffering action of these fabrics toward sudden changes in indoor or outdoor temperatures (2l). A compilation of the specific heat of a variety of textile fibers at 20-200°C indicates that considerable variation in the values of this thermophysical property occurs with different fibers (e.g., a value of 0.157 for glass and 0.1 9 cal/g.°C for Nylon 66 are reported), and that additional research is needed to establish the extent to which specific heat affects the characteristics of thermal transmission in textiles (22). 

Spencer-Smith critically and thoroughly reviewed the physical basis of clothing comfort in four recent papers and discounted much of the previous work on heat and water vapor transmission through clothing assemblies (69, 70, 71, 72). In the first paper (69), he focuses on the special properties of hygroscopic fabrics such as linen and wool and points out that previous studies demonstrate that their buffering action affords comfort in moving from warm dry atmospheres to cold damp ones... 

Each of the components, polymer and metal, has both thermal and hygroscopic expansion coefficients which may differ between components by orders of magnitude. Thus, the very act of fabrication introduces internal stresses into the device. If permitted to act, these stresses are capable of ripping apart the device, destroying it Such destruction is prevented by strong interfacial adhesion, maintained at every step during manufacture, as well as throughout the use life of the device. 

The incipient decay region should not be overlooked as a primary factor in determining the effect of the solidified region on the artifact unit (Figure 14). This field, as the most occluded and restrictive, is often not engaged by the consolidant. As it provides the interface between sound fabric and consolidated fabric, its diminished resistance if often further reduced by hygroscopic and mechanical forces. Failure commonly occurs at the perimeter of the consolidation in an incipient decay field. 

Because the artifact is simple, not joined, and for all purposes fabricated from a single material, hygroscopic alteration is a consideration only with respect to the materials of consolidation. 

Potential Load. The artifact will be mounted in a permanent exhibition room in a diagonal position that reflects its original orientation. The room will have moderate environmental controls. The artifact will be lagged to a secure metal stanchion. Interactive energy will most likely consist of static and hygroscopic load the primary concern is material collapse or fatigue and the interface between the consolidation system and intrinsic fabric. 

Since absorbed water can cause catalyst decomposition and hence incomplete polymerization and since lactam monomer flakes are highly hygroscopic, the melting of monomer is carried out under appropriately controlled temperature and humidity conditions. All additives are also completely dried and then mixed with the monomer in stainless steel vessels while flushing with inert gas under thermostatically controlled temperature. Molds can be of the single type fabricated from silicone rubber, epoxy, or sheet steel or the more expensive tool steel used in tight tolerance cast-to-size parts casting. 

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