Textile Formation

Textile formation processes offer different means of creating a product from fibres and yarn. Each process and product has its own particular advantages and individual price. In order to create a product which best fulfils the technical and economic requirements of each application in build-... 

It is reported that no visible damage to the nanotube yams is imparted by the braiding process and the 3-D braids are very fine, extremely flexible, hold sufficient load, and are well suited for the use in any other textile formation process, or directly as reinforcement for composites. The reported elastic and strength properties of carbon nanotube composites so far are rather low in comparison with conventional continuous carbon fiber composites. It is believed that the properties can be substantially improved if the processing methods and stmctures are optimized [191]. 

Sir Joseph Swan, as a result of his quest for carbon fiber for lamp filaments (2), learned how to denitrate nitrocellulose using ammonium sulfide. In 1885 he exhibited the first textiles made from this new artificial sHk, but with carbon fiber being his main theme he failed to foUow up on the textile possibihties. Meanwhile Count Hilaire de Chardoimet (3) was researching the nitrocellulose route and had perfected his first fibers and textiles in time for the Paris Exhibition in 1889. There he got the necessary financial backing for the first Chardoimet silk factory in Besancon in 1890. His process involved treating mulberry leaves with nitric and sulfuric acids to form cellulose nitrate which could be dissolved in ether and alcohol. This collodion solution could be extmded through holes in a spinneret into warm air where solvent evaporation led to the formation of soHd cellulose nitrate filaments. 

Binders. Latices are used as fiber binders by the paper and textile industries. The two principal methods of appHcation are (/) wet-end addition, wherein the ionic latex is added to a fiber slurry and then coagulated in the slurry prior to sheet formation, and (2) saturation of the latex into a formed fiber web wherein the latex is coagulated by dehydration. Latices are also used as binders for particulate matter such as mbber scrap. 

Nonwoven technologies that employ machinery and processing principles traditionally used to manufacture textile, paper, or extmded materials, when viewed collectively, form what may be termed the primary or basic nonwoven fabric manufacturing systems. These systems are or can be continuous processes. Common to each of these systems are four sequential phases fiber selection and preparation, web formation, bonding, and finishing. 

Textile fibers can be air-formed ditectiy into end use configuration by including a shaped condensing surface or, as in the production of pillows, an air-permeable collection package. Aerodynamic web formation is a suitable means for processing brittie fibers such as glasses and ceramics, and stiff fibers such as metaUics and wood. 

As a general rule, however, textile fibers do not wet out readily, are difficult to disperse, and tend to tangle with one another. Consequendy, large amounts of water are necessary to keep the fibers suspended. Further, if the slurry is not handled propedy, the fibers tangle and cause poor sheet formation. Two approaches to resolving these difficulties are increasing slurry—dilution ratio and controlling fiber orientation. 

Monobasic aluminum acetate (eg, aluminum subacetate), aluminum formoacetate, normal aluminum formate, and basic aluminum formate have found widespread use as mordants in dyeing, in the formulation of waterproofing compositions for textiles, and for dermatological treatment. 

Most commercial aluminum formate is monobasic aluminum diformate because of the difficulties involved in triformate preparation. The main appHcation is in textile waterproofing. Aluminum formate reacts with casein to form a water-soluble complex, which can emulsify paraffin and certain other waxes. Fabrics immersed in these emulsions are rendered water repellent (26—28). 

After the fabric formation process, textiles are generally subjected to either dyeiag or printing and to a variety of mechanical and chemical finishing operations. The specific nature of the dyeiag and finishing operations depends on the fiber type and on the iatended use of the fabric. 

The presence of ammonia during hydrogenation suppresses formation of secondary amines and inhibits hydrogenation of double bonds in unsaturated nitriles. Eatty amines are used as corrosion inhibitors, flotation agents, quaternary salts for sanitizing agents and textile fabric softeners, and surface-active agents. 

Branched-chain acids have a wide variety of industrial uses as paint driers (7), vinyl stabilizers (8), and cosmetic products (9). Cobalt and manganese salts of 2-ethyIhexanoic acid and neodecanoic acid are used as driers for paint, varnishes, and enamels litbium, magnesium, calcium, and aluminum salts of 2-ethyIhexanoic acid are used in the formation of greases and lubricants (see Driers and metallic soaps). Derivatives of isostearic acid have been used as pour point depressants in two-cycle engine oils, as textile lubricants, and in cosmetic formulations. Further industrial appHcations can be found (10). 

Porous Media Packed beds of granular solids are one type of the general class referred to as porous media, which include geological formations such as petroleum reservoirs and aquifers, manufactured materials such as sintered metals and porous catalysts, burning coal or char particles, and textile fabrics, to name a few. Pressure drop for incompressible flow across a porous medium has the same quahtative behavior as that given by Leva s correlation in the preceding. At low Reynolds numbers, viscous forces dominate and pressure drop is proportional to fluid viscosity and superficial velocity, and at high Reynolds numbers, pressure drop is proportional to fluid density and to the square of superficial velocity. 

The use of aromatic brominated compounds as flame retardants has been a potential source of environmental contamination. Incomplete incineration of these compounds and wastes (plastics, textiles, oils etc...) containing brominated flame retardants caused formation of brominated/chlorinated dibenzodioxines (PBDDs/ PCDDs) and dibenzofurans (PCDFs/PBDFs) (refs. 1 - 4). 

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