Textile performance, mechanics characteristics

Among the listed embroidered conductive textiles in Table 10.1, those noted as (6) exhibit the best combination of RF performance, mechanical strength, and load-bearing capability (Wang et ah, 2012b Toyobo Co., Ltd, 2005). In this chapter, we evaluate the RF characteristics of these embroidered E-fibers and their applications to antenna design. Of importance is that the materials used for the dielectric substrate of the embroidered textiles must also preserve the flexibility, integrity, and RF performance of the stmcture. In this chapter, we use polydimethylsiloxane (PDMS)... 

The ratio of stress to strain in the initial linear portion of the stress—strain curve indicates the abiUty of a material to resist deformation and return to its original form. This modulus of elasticity, or Young s modulus, is related to many of the mechanical performance characteristics of textile products. The modulus of elasticity can be affected by drawing, ie, elongating the fiber environment, ie, wet or dry, temperature or other procedures. Values for commercial acetate and triacetate fibers are generally in the 2.2—4.0 N/tex (25—45 gf/den) range. 

The mechanical properties of a conductive material play an important role when selection is performed for any particular textile application. Metallic filaments usually compromise good electroconductive characteristics with poorer mechanical properties. A very high stiffness and lower stretchability of metallic fibers not only makes the woven or knitting process difficult but also reduces their service life. On the other hand, polymeric fibers or yams exhibit good elongation and recovery properties. The combination of nonstretchable metallic fibers with stretchable polymeric yams creates a new class of metal-based electroconductive fibers, which is known as co-spun polymeric-metal yams (Fig. 28.3). 

Traditional snrface treatments (Hatch, 1993) are often limited because laundering, or even normal use of the treated garment, may cause removal of the active agents. The use of chemically bound reagents on the fiber may also have a negative influence if restrictions at the binding site alter the mechanical behavior of the fiber. Modification at air-fabric and fluid-fabric interfaces is of particular relevance to textile chemistry because many performance characteristics are critically dependent on the behavior of this region. 

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