Applications split fiber

The mechanical properties of split film yams are comparable to that of filament yam or staple yam. Melt spun filaments exhibit a circular and highly uniform cross-section. Film-based fibers have rectangular, lemon-type or a banana-type cross-section and larger diameter variation. These differences result in changes of softness, handling, resilience, bulk and fiber to fiber friction. The main applications of split fibers are summarized in Table 2. 

Keywords use, application, chemical fiber, polypropylene fiber, monofilament, multifilament, staple fiber, tapes, spunbond, melt blown, split film, textile yarn, knitted fabrics, clothing, nonwoven fabric, home textiles, upholstery, geotextiles, agrotextiles, composites, medical textiles, automotive textiles, bulk continuous filaments (BCF), Eco-textiles, integrated fabric. 

Much polypropylene fiber is not spun, but produced from film. A film is blown, or cast on a chill roll, drawn 6-10 times and then fibrillated. There are numerous ways of slitting, fibrillating, and cutting. Split fiber finds applications in twines and ropes (as a replacement for sisal), cheap fabrics for bags and tarpaulins, and carpet backing (replacing jute). 

PBS is a typical thermoplastic and can be processed via various methods, such as extrusion, injection molding, film blowing, fiber spinning, and thermoforming. It has been reported that PBS can be processed into melt-blown, multifilament, monofilament, nonwoven, flat and split yarn, injection-molded products, film, paper laminate, sheet, and tape for applications in the textile and plastic industries. 

Nonmetallic inorganic materials are widely used for optical purposes lenses, pigments, interference filters, laser hosts, luminescent coatings, displays, solar cells, fiber optics, lamp bulbs, and tubes. For optical applications use is made of the refractory index, light absorption, luminescence, and nonlinear optical behavior of materials. These are intrinsic but may depend on the concentration of impurities. Refraction index and optical absorptivity in insulators are atomic properties and are only indirectly related to the structure, but the structure affects the selection rules and the term splitting in the atomic chromophores. The coordination number determines the intensity and wavelength of absorption and... 

Table 2 Areas of applications of split PP fibers. Dimensions in mm, fineness (titre) in dtex, tenacity in cN/dtex, elongation and shrinkage in % units.

From market point of view and from the structure of the fiber industry, the future for film fiber products may lie in the careful choice of application area, choosing applications where cheap fibrous materials or small-volume specialities are involved. In the tex range > 1, there is a huge application potential for split film yarns. Table 2 gives a selection of various applications. 

Reverse Osmosis. This was the first membrane-based separation process to be commercialized on a significant scale. As described previously, the breakthrough discovery that made reverse osmosis possible was the development of the Loeb-Sourirajan as5mimetric cellulose acetate membrane. This membrane made desalination by reverse osmosis practical within a few years commercial plants were installed. Currently, the total worldwide market for reverse osmosis membrane modules is about 300 million/year, split approximately between 15% hollow-fiber and 85% spiral-woimd modules. The general trend of the industry is toward spiral-wound modules for this application, and the market share of the hollow-fiber products is falling (75). 

Fig. 5.12 Fibers containing titanium dioxide are commonly employed for various textile applications. SEM of a fiber surface, without finish (A), shows a surface split, likely caused by such a particle at or near the surface. A similar region at higher magnification is shown in both SEM (B) and high resolution SEI (C) micrographs. The defect region is not very clear in image (B) taken in a dedicated SEM, but the higher resolution image provides interesting detail (D and E). Particles, voids and microfibrils (arrows) are observed.

Long molecules that compose the cellular cytoskeleton can be treated from the standpoint of polymer mechanics where the response of the material to the application of a force is associated with changes in entropy (transition from disorder to more order). The cytosfceletal fibers are treated either as chains of segments that are completely free to move in three directions (freely joined chain model) or as flexible slender rods (worm-Hke chain model). The same approaches are apphed to cellular components, such as the cytoskeleton, membrane, and nucleus. There is an important distinction in the models of relatively thin cellular membranes. They are considered either as shells with a certain stress distribution across the thickness or as intrinsically two-dimensional continua. In both cases, the mechanical parameters are split into two groups moduli characterizing the in-plane properties and those characterizing the out-of-plane bending and twist of the membrane. 

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