Nonwoven fabrics other performances

Other performances in relation to nonwoven fabric applications are also defined in EDANA/EMDA, ISO, and ASTM standards. Some examples are as follows ... 

As engineered stmctures, nonwovens can be designed to have appearances, textures, and other aesthetic properties comparable to traditional wovens and knits, and performance and functional properties superior to traditional wovens and knits. Nonwovens are, indeed, a distinct class of fiber-based materials with the characteristics of fabric and many of its useful properties. 

In Sections 24.3 and 24.5 the flammability and fire resistance of individual fiber/fabric type are discussed. However, as also discussed before, the fire resistance of a fabric not only depends upon the nature of components and the FR treatments applied, but also on fabric area density, construction, air permeability, and moisture content. Nonwovens, for example, will have superior properties to woven or knitted structure, even if all other variables are kept the same.93 The air entrapped within the interstices of any fabric structure and between layers of fabrics within a garment assembly provides the real thermal insulation. For effective thermal and fire resistance in a fabric structure, these insulating air domains need to be maintained.22 In general, for protective clothing and fire-block materials, for best performance multilayered fabric structures are employed. The assembly structures can be engineered to maximize their performance. It is beyond the scope of this chapter to go into details of these composite structures hence the reader is referred to the literature on specified applications and products available. 

Different types of reinforcement construction are used to meet different RP properties and/or simplify reinforcement layup fabricating processes to meet design performance shape requirements. They include woven, nonwoven, rovings, preforms, and others. These different constructions are used to provide different processing and directional properties. 

The thermal stability of polypropylene fabrics at temperatures below melting point (120-135°C) has been improved markedly by the addition of stabilizers. This, along with the inherent stability to a wide variety of chemicals, has allowed both woven and nonwoven polypropylene fabrics to be used in filtration and a wide range of other industrial uses. At temperatures below the melting point, the stability of polypropylene fabrics rivals any but the most expensive high-performance fibers. 

The silica-based fibres are typified by Quartzel (Saint-Gobain, France), which while having slightly inferior fire and heat performance to alumina-based fibres (see Table 8.5), are available as continuous filament yams, rovings, and chopped strands (each comprising 9 or 14 pm diameter filaments) and sewing threads, filament-based nonwovens, and wetlaid papers. Continuous filament yams may be knitted and woven to yield fabrics with applications in furnace insulation, combustion chamber insulation in aircraft, ablative composites for military and other markets, and hot corrosive gas and liquid filtration. 

Fabrics that are woven together from thread or yam are referred to as textiles, whereas shorter fibres bound together in a random, porous fashion are called nonwovens. In either case, crosslinkable latexes are extensively used as binders to improve stability, durability, and chemical resistance (205), and flame retardance (413). Acrylic copolymers are the most common class of binders, although other copolymers, such as styrene-butadiene or ethylene-vinyl acetate (242, 255) copolymers are often used when required by cost (247) or performance. The softness (flexibility) or hardness (strength) of the fabric is controlled through the glass transition temperature of the latex binder. 

Porous PE nonwoven, breathable fabric is used as the strength component and starting material for both a perforated housewrap as well as several non-perforated breathable films in many other applications. These products are designed to offer the end nser a range of products and performance up to the highest grade of breathable film housewrap. 

Moreover, there were other reports on the electrospun PI composite Qin et al. reported the fluorescent performance of electrospun PI web mixed with hemicyanine dye (Figure 9), pointed out that the nano fiber structure were helpful to the fluorescence (Qin et al., 2009) Cheng et al. reported the preparation of nonwoven Pl/silica hybrid fabrics by combining electrospinning and controlled in situ sol-gel techniques, their product had better mechanical and thermal properties than ordinary PI electrospun fabrics (Cheng et al., 2009). 

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