Fibre properties cross-section

Many other properties have to be considered, especially for apparel fibres, e.g., moisture absorption, ability to dye, drape, texture, weaving characteristics, etc. Many of the properties are influenced by the cross-section profile of the fibre. Thus cotton and some rayons (an artificial synthetic fibre derived from cellulose) are a hollow round fibre silk has a triangular shape giving it a fine lustre and drape. 

From the above results, it can be concluded that PAN fibres resulted in the desired conductive behaviour and will be used further in this investigation. Microscope images of the cross-section of PAN fibres treated with NiCl2 show that after thermofixation of the fibre, no swelling is obtained. Therefore thermofixation will be an important step in the production process and will also be taken into account in the following steps of this investigation. Finally, it should be pointed out that similar absorption behaviour of PAN fibres for Co and CoS was observed but, contrary to Ni, this led to much weaker electroconductive properties of the metallised fibres. 

The topography of cross-sectional surfaces produced by cutting and polishing usually reflects the differences in mechanical properties of its heterogeneities. In general, this is due to the fact that the rate of material removal of hard components like fibres and metals is smaller than that of soft polymeric components. Easily deformable components like rubber inclusions, however, tend to be more compressed rather than abraded and their surfaces are quite often above that of the surrounding material of the final cross-section. 

Permeability is a parameter defined to measure the physical influence of a porous structure on fluid flow, and for a CVI process it is an important physical parameter for fibre preforms. Another important parameter for porous structure is the porosity, which is the most important geometrical property. According to Darcy s law, the volumetric flow rate Q of a fluid through a porous medium is proportional to the hydrostatic pressure difference (AP) across the structure (see Figure 2.16), the permeability and the cross-section area, and is also inversely proportional to the length of the structure and the viscosity of the fluid, as given by [26]... 

The modacrylic fibres have similar properties to those of acrylics and are flame resistant..Mostly this fibre is based on a 60/40 or 50/50 copolymer of acrylonitrile with vinylidine chloride (CH = CCy together with small proportion of ternary monomer to improve ionic dyeability or hydrophilicity. The better known modacrylic fibres have a ribbon-shaped or pea-nut shaped cross-section. One problem encountered with modacrylic fibre is loss of lustre at the boil [83, 84]. This fibre is used for apparel, home furnishing, wigs etc. 

Figure 1-31. Repeat units of some chlorofibres. temperature is low with considerable shrinkage at 70 C and have poor dyeability at moderate temperatures. These fibres are mainly used in filter cloths, flying suits (in which their property of non-flammability is an asset), curtains (owing to their resistance to degradation of light) and fishing nets (owing to their resistance to water). These fibres have regular round, dogbone or dumbell shaped cross-section and transparent, even and smooth. They are highly lustrous and silky in hand. 1.8.2 Poly (vinyl alcohol) fibres...

Fibres, containing derivatives of bis-aroilenbcnzimidazole, were subjected to ultra-violet light action of the lamp PRK-2. Mechanical properties of the fibres were determined depending on cross section area. Value of rupture stress (o) is the mean value of true rupture stress obtained from indexes of tearing machine. 

Self-assembly is an intricate technique to build nanofibres from small molecules or polymers into bricks. There are various patterns in which molecules are assembled into nanofibres. For example, a designed amphiphile (i.e., a molecule with both hydrophilic and hydrophobic blocks and properties) can be induced to self-assemble into a cylindrical nanosized fibre. It can be seen that, at any cross section, the amphiphiles have... 

Based on the yam volume description, the fibrous stmcture of the yarn, or, more generally, the fibrous stmcture of the unit cell, is described as follows. Consider a point P and the fibres in the vicinity of this point. The fibrous assembly can be characterised by physical and mechanical parameters of the fibres near the point (which are not necessarily the same in all points of the fabric), fibre volume fraction Vf and direction /of them. If the point does not lie inside a yam, then Ff = 0 and/is not defined. For a point inside a yam, fibrous properties are easily calculated, providing that the fibrous stmcture of the yam/ply in the virgin state is known and its dependency of local compression of the yarn/ply, bending and twisting of the yam are given. Searching the cross-sections of the yams, cross-sections S, = S(si) and S,+i =5 (s,+i) (s is a... 

Wool and cotton fibres are still iding applications in leisure wear. S5 thetic fibres can either be modified during manufacture, for example, by producing hollow fibres and fibres with irregular cross-section, or be optimally blended with natural fibres to improve their thermophysiological and sensory properties. Synthetic fibres with improved ultraviolet (UV) resistance and having antimicrobial properties are also commercially available for use in sportswear. 

Man-made fibres are normally spun as continuous filaments by means of spinneret technology. The cross-section and surface of these fibres can be widely modified, particularly when different spinneret cross-section geometries are utilised from round to profiled, solid to hollow, smooth to structured or crimped. The cross-section has a considerable effect on visual properties such as lustre, colour, transparency and cleanabiUty and on the physiological properties of moisture transfer and heat insulation. 

Melamine fibres are primarily known for their inherent thermal resistance and outstanding heat blocking capability in direct flame applications. This high stability is due to the cross-linked nature of the polymer and the low thermal conductivity of melamine resin. The dielectric properties and its cross-sectional shape and distribution make melamine ideal for high temperature filtration applications. It is sometimes blended with aramid or other high strength fibres to increase final fabric strength. 

In addition, the external cross-sectional shape must be rectangular with width 250 mm and depth up to 40 mm, and the weight should be as low as possible. It is proposed to manufacture the new product as an extruded hollow box section, reinforced if necessary by longitudinal webs (see the box section in Figure 8.16). The chosen material is short glass-fibre reinforced polypropylene (GF-PP) with properties given below. 

In textiles PVDF is used in form of monofilaments, hollow fibres and meltblown non-wovens. In architecture coatings of PVDF are applied to technical textiles of polyester or nylon. Recently results of electro spun PVDF have been published [And-08]. Polisilk SA, Manresa, Spain, is the only known producer of multifilWents, but having only one fineness (500 denier, 42 filaments and 1000 denier, 84 filaments). At RWTH-ITA yams with finer filaments and different cross section have been spurL Successful product development for medical purpose as well as promising properties and results were the motivation to intensify research on PVDF multifilamertt yams. 

---