Tension textiles

In the days of central steam engines in factories, ropes were part of the way in which power was transmitted to machines, but that application became obsolescent when individual electric motors replaced steam engines. It is now only in common uses of tension textiles, such as hoists and tying up goods for dispatch, that ropes and other cordage are found. 

There is also an opportunity to use fibre ropes as tension textiles in buildings. An example is a bus station in Cambridge, UK (Fig. 13.25), erected in 1991. The structure was designed with four masts, each with a pair of forestays and back stays to support the 7-metre cantilevered roof. The stays are made of Parafil ropes with a Kevlar core their function is primarily to resist snow loading, but they are permanently stressed to... 

Most of the chapters in this volume relate to specific functions from ballistic protection to transportation. In contrast to this, ropes and cordage are found in a wide variety of human activities from mooring oil rigs to tying up a parcel. Ropes and cords have an amazing diversity of uses as one-dimensional tension textiles. Inevitably, not all have been mentioned. Rescue ropes for many situations, sewing up wounds, ski tow ropes. 

Fig. 89.1 Port Augusta to Lake Eyre Pipeline Corridor. A slightly different course might prove better if only the South Basin is to be filled at the Lake Eyre terminal south of the proposed Goyder Channel Tension Textile Dam. (Source Feieidoun Ghassemi Ian White, 2006, Fig. 7.5, p. 146)...

An important aspect of the mechanical properties of fibers concerns their response to time dependent deformations. Fibers are frequently subjected to conditions of loading and unloading at various frequencies and strains, and it is important to know their response to these dynamic conditions. In this connection the fatigue properties of textile fibers are of particular importance, and have been studied extensively in cycHc tension (23). The results have been interpreted in terms of molecular processes. The mechanical and other properties of fibers have been reviewed extensively (20,24—27). 

Spandex Fibers. Spandex fibers are suppHed for processing into fabrics in four basic forms as outlined in Table 3. Bare yams are suppHed by the manufacturer on tubes or beams and can be processed on conventional textile equipment with the aid of special feed and tension devices. In covered yams, the spandex fibers are covered with one or two layers of an inelastic filament or staple yam the hard yam provides strength and rigidity at full extension, which faciUtates knitting and weaving. 

The low surface tension of highly fluorinated organic compounds is commercially important for their appHcation in surfactants, antisoiling textile treatments, lubricants, and specialty wetting agents. 

Grease Retention, Wrinkle Resistance, and Durable Press. On bending or creasing of a textile material, the external portion of each filament in the yam is placed under tension, and the internal portion is placed in compression. Thus, the wrinMe-recovery properties must be governed in part by the inherent, tensional elastic deformation and recovery properties of the fibers. In addition to the inherent fiber properties, the yam and fabric geometry must be considered. 

An older method of cellulose fiber modification is mercerization [22,33-36], which has been widely used on cotton textiles. Mercerization is an alkali treatment of cellulose fibers. It depends on the type and concentration of the alkalic solution, its temperature, time of treatment, tension of the material, and the additives used [33,36]. At present there is a tendency to use mercerization for natural fibers as well. Optimal conditions of mercerization ensure the improvement of the tensile properties [33-35,37] and absorption characteristics [33-35], which are important in the composing process. 

By applying a sufficient high cord tension this can be avoided. However, cord tension might cause some elongation. The duration of application of high cord tension has to be as short as possible in order to avoid creep. The complete upstream and downstream of the calender is mainly dedicated to maintain the preset cord tension. In order to keep the cord tension as low as possible the tension can be set in 3-5 steps. One (or two) in the textile upstream, one in the calender area, and... 

A surfactant was defined in Chapter 8 as an agent, soluble or dispersible in a liquid, which reduces the surface tension of the liquid [1]. It is helpful to visualise surfactant molecules as being composed of opposing solubility tendencies. Thus, those effective in aqueous media typically contain an oil-soluble hydrocarbon-based chain (the hydrophobe) and a smaller water-solubilising moiety which may or may not confer ionic character (the hydrophile). The limitations of space do not permit a comprehensive detailed treatment of the chemistry of surfactants. The emphasis is therefore on a broad-brush discussion of the principal types of surfactant encountered in textile preparation and coloration processes. Comprehensive accounts of the chemistry and properties of surfactants are available [2-13]. A useful and lucid account of the chemistry and technology of surfactant manufacturing processes is given by Davidsohn and Milwidsky [ 14] ... 

Table 10.48 Surface tension of a range of liquids and surface energies of a range of textile fibres [502]...

Liquid Surface tension (mN/m) at 20 °C Textile fibre Surface energy (mN/m) at 20 °C... 

Mercerization A process for modifying cotton textiles by treatment with alkali. The alkali is cold, conentrated aqueous sodium hydroxide it is subsequently removed by washing with acetic acid. The process is generally conducted while the textile is held under tension. The product has improved lustre and is easier to dye. Invented by J. Mercer in 1844. 

Industrially, silicone surfactants are used in a variety of processes including foam, textile, concrete and thermoplastic production, and applications include use as foam stabilisers, defoamers, emulsifiers, dispersants, wetters, adhesives, lubricants and release agents [1]. The ability of silicone surfactants to also function in organic media creates a unique niche for their use, such as in polyurethane foam manufacture and as additives to paints and oil-based formulations, whilst the ability to lower surface tension in aqueous solutions provides useful superwetting properties. The low biological risk associated with these compounds has also led to their use in cosmetics and personal care products [2]. 

Certain Investigators, however, have expressed interest in the matter recently. The possibility that a history of asthma may increase the probability of an acute byssinotic reaction to cotton dust is suggested by a paper by Hamilton et al. ( ). The senior author of this paper had had asthma as a child. Promptly after exposure to the air in a dusty part of a cotton mill he exhibited pronounced shortness of breath with tightness in the chest and accompanying major temporary decreases in FEVi and arterial oxygen tension. The episode is described as "byssinosis". The authors remark It is unlikely that many textile workers with an initial response to cotton dust such as the one described here would remain working in dusty areas." Although the authors state that "It is not possible from the present study to conclude that a prior history of atopy confers sensitivity to cotton dust", the present writers were left with the impression that the authors suspect that such may be the case. 

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