Dyeing process surface

Batcheller et al. also discuss the influence of the dyeing process on the composition of the fibre s surface. They note that high alkalinity/acidity and extended processing time result in loss of surface lipid. Nevertheless, the dyeing process has limited influence on the ageing process due to light exposure. 

Differences in geometry and polarity of the dye molecules can lead to wide variations in these finishing or dye-specific properties and can have a marked effect on the absorption characteristics of all dyes, irrespective of whether singlecomponent or combination dyeing processes are used. For instance, uneven dyeing may occur when an unequal distribution of particle size results in insufficient dispersion stability and hence crystal growth and precipitation at the substrate surface. 

There are both process aids and cleaning application uses of surfactants in the textiles field. Surfactants are used to help produce and process fibres into cloth which, once produced, needs to be cleaned prior to the dyeing steps. Surfactants also find use as auxiliaries to the dyeing process to help lay down consistent levels of dyes on fibre surfaces. 

The main conceptual advance made in the last few years is the acceptance that electron-transfer process at dye-sensitised systems under barrierless conditions can be purely electronic. A measurement of the nonradiative decay channel due to electron transfer under these conditions gives a direct determination of the electronic coupling. Subsequent to the initial work pointing this out, there have been a number of determinations of extremely fast electron-transfer times at dye-sensitised surfaces. For dye-derivatised TiOi electron-transfer times from 10 fs to 100 fs have been reported by a number of groups (Rehm et al, 1996 Tachibana et al, 1996 Hannappel et al,... 

A number of publications review sulfonation and sulfation primarily from the chemical standpoint regardless of product use. Other treatises discuss the process as applied to the manufacture of important products such as dyes and surface-active agents. ... 

The dyeing process comprises mordanting of the fabric and the actual dyeing procedure. Thus, wool or cotton are first steeped in potassium alum (KA1(S04)2 X 12 H2O) and then treated with steam. Thereby, finely dispersed aluminium hydroxide is precipitated onto the surface of the fibres. For the dyeing step, the alum-mordanted wool or cotton is boiled with a fine suspension of alizarin for a longer period. [58]... 

Wetting is often one of the first steps for the effect of a surfactant. A special case is the penetration of fluids into porous material such as a bundle of fibres in the dyeing process or the stone matrix in enhanced oil recovery. One of the steps of lubrication is wetting of the surfaces by lubricant liquids. Because often further conditions have to be considered, the use of phosphorus-containing surfactants can be favourable. 

Polar, Uncharged Surfaces. Polar, uncharged surfaces include many of the synthetic polymeric materials such as polyesters, polyamides, and polyacrylates, as well as many natural materials such as cotton and silk. As a result of their surface makeup, the mechanism and extent of adsorption onto such materials is of great potential technological importance, particularly in terms of dyeing processes, waterproofing, and detergency. The mechanism of adsorption onto these surfaces can be much more complex than that of the nonpolar case discussed above, since such factors as orientation will be determined by a balance of several forces. 

Dye removal from fabric is the major culprit in color degradation. This tends to be an issue on cottons more so than synthetic fabrics. In synthetics, the color is typically spun into the fiber during synthesis. With cottons, the dye is applied to the surface of the finished cloth. Detergents are designed to removal materials from the fabric surface, and dyes are no exception. The degree of dye removal depends on a number of factors, such as the chemical composition of the dye, the dyeing process, additional fabric finishes and dye fixatives, and the type of detergent used. 

Almost every leather is dyed, mostly with synthetic organic colors. The majority of the dyes used are anionic azo dyes which bind to the cationic surfaces of the leather. For completion of the dyeing process, formic, acetic or lactic acid is added. Afterwards, basic dyes can be applied which give the leather a brilliant... 

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