**2.3 Effect of fabrics**

238 Woven Fabrics

Crystallinity also affects the handle of the fabrics by influencing the way that the fibers move and respond to bending. If the molecules in a fiber are aligned along the fiber axis, the fiber will be strong in uniaxial tension along the fiber axis. A more crystalline fiber is more

The twist of the yarns which the fabrics are made of, is one of the main parameter affecting the fabric behaviour including bending, stiffness and shearing property (Shanmugasundaram, 2008). The amount of twist, together with the characteristics of the fibers (luster, hand, cross-sectional shape, etc.), determines the appearance and feel of the yarn. Fabrics composed of yarns with higher levels of twist are known to have higher bending stiffness, less compressibility, less fiber mobility, lower surface friction, less bulkiness than similar fabrics composed of yarns with less twist. Increased yarn twist leads to greater internal (fiber-to-fiber) friction within the yarn structure and reduce softness and

Another factor affecting handle is the number of the yarns folded. In plied yarns, i.e. two or more single yarns twisted together, the stiffness is increased compared to single yarns

Filament yarns are sometimes put through an additional process known as texturizing. The process modifies the handle of the filament yarns by adding bulkiness and/or stretchiness to the filaments and therefore changes the smooth surface feel of fabrics (Behery, 2005). The feel of textured-yarn fabrics against the skin is considerably different than that of flat-yarn fabric. Textured yarns give a fabric more pleasant hand, fabric becomes warmer and softer and it has

Fiber linearity and fiber-packing density in yarn structures are also important for the tactile qualities of a fabric, when not masked by twist (Behery, 2005). Comparing multifilament yarns of the same size and fiber composition, yarns containing more filaments (finer) are much less stiff than multifilament yarns containing less filaments (coarser). Fabrics produced from coarser filament textured yarns have higher thickness, compression characteristics than that of the fabrics made of finer filament textured yarns but there is no

Yarn type has a significant effect on the handle properties of the fabrics. The static friction coefficient of cotton fabrics made of combed ring spun yarn is much lower than that for fabrics made of rotor yarn due to the more regular, denser and smoother structure of the ring spun yarn compared to the rotor yarn, on the surface of which there are visible wrapped fibers. The plain weft knitted fabric produced from the sirospun yarn is thicker, softer, of poorer recovery from compression, less rough and less stiff. For finer sirospun yarn, the shape retention is worse as the hysteresis of bending and shear is greater. (Sun & Cheng, 2000). Air-jet spun yarns produce thicker, less compressible, more extensible and stiffer fabrics than fabrics made

The fancy yarn structure also influences the subjective handle properties of the fabrics. In the production of fancy yarns, as the feeding rate increases; the fabric thickness, fabric weight, bending rigidity and friction coefficient of the fabric increase (Özdil et al., 2008).

bulkiness, in general, and hairiness in the case of spun yarns (Behery, 2005).

less synthetic feeling (Shanmugasundaram, 2008; as cited in Mahar & Pestle, 1983).

significant difference in fabric recovery and resiliency (Mukhopadyhay et al., 2002).

from ring spun yarns (Behery, 2005; as cited in Vohs et al., 1985).

resistant to bending (Behery, 2005).

**2.2 Effect of yarns** 

(Shanmugasundaram, 2008).

The handle of the fabrics is affected by mainly fabric structure and fabric geometry. Fabric construction and yarn densities play major role in determining fabric handle (Shanmugasundaram, 2008; Na & Kim, 2001). Variations in warp and weft densities and in the number of warp and weft yarns have significant effects on the handle characteristics of the fabrics (Shanmugasundaram, 2008). Sensory analysis shows that fabric hand can be influenced more by fabric weave than by the component yarn. Weaves that use fewer yarn interlacing improve the handle characteristics of the fabrics (Behery, 2005; as cited in Vohs et al., 1985).

Fabrics for which the warp and weft twist are unidirectional (Z & Z twist direction) perform higher shearing rigidity, (smooth rounded curvature) in comparison to those for which the warp and weft twist directions are opposite to each other (Yazdi & Özçelik, 2007).

The tightness factor of the knitted fabrics is another factor affecting the handle, with the increment of this factor, stiffness, which is related to bending rigidity, increase. Fullness, softness and smoothness decrease with the higher tightness factor (Park & Hwang, 2002).

Nonwoven fabrics differ from knitted or woven fabrics, because they are not based on webs of individual fibres, which can be bonded to each other by several means that changes the texture ranges from soft to harsh. Fiber composition influences performance far more for nonwoven fabrics than for fabrics containing yarns. High strength combined with softness is one of the most difficult property combinations to be achieved in nonwoven fabrics because the geometrical factors that permit high strength also lead to increased stiffness (Shanmugasundaram, 2008).
