Effect of Fabric Construction

It has long been realised that, in fluid flow through multifilament fiibrics, a considerable proportion of the fiJ trate can pass throng the yam strands in the cloth. 

The relative amount of flow through and around the yams in such cloths will depend on the degree of twist in arted to the yam and the saze of the apertures between yams. The aperture size will, in turn, depend on the weave pattern plain, twill, sateen, etc.. 

This division of flow has technical inq ortance in those circumstances where the fine particles present are small enough to follow the flow into the yam. Once inade the yam, removal of these particles is effected with great difficulty. A tightfy twisted, closely woven cloth will approach the constractional and filtration characteristics of a monofilament cloth hut also will generally exhibit better mechanical properties. The effect of cloth constmction is discussed in detail below in the section dealing with mathematical models of flow in filter fabrics. 

Swelling of fabrics can change the nature of flow in that closure of the cloth pores can force an increasing amount of flow through the yams. This has been rq orted in studies using cotton, wool, linen and natural fibres [Smith, 1951]. In the latter it was recorded that up to 98% of the flow takes place through the yams of such fabrics after swelling. 

the relatively poor mechanical properties of monofilaments such as stretching. 

---

Table 2. Effect of Fabric Construction on Traction Characteristics ...

Collins, J. E., An Investigation of the Effect of Fabric Construction on the Color Fastness of... 

Heim F. and Gupta B.S., Textile heart valve prostheses the effect of fabric construction parameters on long-term durability , Text Res I, 79(11), 1001-1013, 2009. 

The influence of fabric construction and garment manufacture on flammability and thermal protection has been studied extensively. Fabric construction and weight per unit area play an important role in determining suitability for different applications. Table 10.3 shows the effect of area density and its increasing effect on limiting oxygen index (LOl) valne for a number of fibre types. Different fabric weights have... 

Table 10.6 Effect of fahric constructional parameters on protection for PBI fabric ...

The type of fabric construction is also important, in that it affects the fabric s physical and mechanical properties, and its effectiveness as an electrical conductor. Whatever type of construction is used, it is important that the yarns constituting the fabric are sufficiently close together. If the fabric is too porous, the thin layers comprising the... 

Recently, scanning electron microscopy has been used in our laboratory to investigate the effects of abrasion on the morphology of fibrous cellulose copolymers (36). For example, cotton cellulose was woven into fabric form (print cloth construction and weight). Cellulose copolymer fabrics were prepared by irradiating a sample of this fabric, followed by copolymerization of the irradiated fabric with a binary mixture of acrylo-... 

The effects of type of vinyl monomer on the properties of copolymer fabrics are shown in Table VII. Two different fabric constructions, print cloth and twill, were used. After the copolymer fabrics were prepared, they were given the usual treatment with dimethyloldihydroxyethylene urea to crosslink the cellulose. The wash-wear appearance ratings, flat abrasion resistances, and, in most cases, wrinkle-recovery angles of copolymer twill fabrics were improved over fabric controls. For copolymer... 

This section described the fabrication of ITO electrodes modified with porphyrin-terminated M(tpy)2 complex wires by the stepwise coordination method, and it is demonstrated that the electronic nature of the molecular wire is critical to the photoelectron transfer from the porphyrin to ITO. These results suggest that the new facile fabrication method of molecular assemblies is effective in the construction of photoelectron transfer systems. The system could be upgraded by extending the wire length, embedding the redox potential step in the wire, increasing the photoreceptors in the wire, and/or incorporating donors and acceptors. 

Photodegradation is a topochemical reaction and thus is affected by fabric and yarn structure (16) and by the fineness and cross-sectional shape of the fibers. The faster deteriorating outer layers are believed to have a protecting effect by allowing less radiation to penetrate the interior of the construction (11,16,17). Because of the irregularity of the attack there may be some variability in the fluidity data of the bulk material (11,17). Desai (17) took the thickness of the material into account and measured the DP of the exposed and the unexposed side separately and found considerable differences in the data. 

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. 

Theoretical values of the effective thermal conductivity of polyester fabrics (6J (estimated by an expression developed for fibers placed in parallel with each other surrounded by a known amount of air and vice versa) agreed well with line heat source measurements of the thermal conductivity of fabrics varying in thickness, construction, and fiber content (7.). These results also indicate that the thermal conductivity of fabrics in directions parallel to the surface is greater than that perpendicular to the surface, especially for filament yarn the thermal conductivity of woven fabrics in directions parallel to the warp yarns, which were arranged more closely, was greater than in directions parallel to the filling yarns (7.) ... 

Howorth (1958,1964) concluded that three fundamental cloth properties determine the handle, viz. stiffness, softness and bulkiness (thickness per unit weight). It appears that the effect of the yam and fabric construction on these properties is at least as great as the effect of the differences resulting from the nature of the polymer. 

---